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Chapter 1: An Introduction to the Structure and Function of the Body



Anatomy- study of the structure of the body
Physiology- study of the function of the body

Structural Levels of Organization:
  • Atoms-(chemical level)
  • Molecule-(chemical level)
  • Cell-smallest living unit
  • Tissue-organization of many cells that act together to perform a common structure
  • Organ-group of several different kinds of tissues arranged so they can act as a unit to perform a special function
  • Systems-most complex unit, organization of varying kinds of organs arranged so that they can together to perform complex fuctions for the body
  • Organism- "the body as a whole"
- Examples: respiratory, skeletal, musclular, nervous, endocrine, cardiovascular, urinary systems

Anatomical Position:
  • The body is erect with arms at the sides and plams turned forward. Feet are turned forward and set slightly apart.
  • Supine-laying face upward
  • Prone- laying face down

Anatomical Directions:
  • Superior-"towards the head", "above", "upper"
  • Inferior-"towards the feet", "below", "lower"
  • Anterior-"front", AKA ventral
  • Posterior-"back", AKA dorsal
  • Medial-"toward the midline of the body"
  • Lateral-"Towards the side of the body or away rom the midline"
  • Proximal-" towards the nearest trunk or nearest to the point of origin"
  • Distal-"away from or farthest from the trunk or point of origin"
  • Superficial-"nearest to the surface"
  • Deep- "farther away from the body surface"



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Planes or Body Sections


To study the individual organs, as well as the body as a whole, it is helpful to divide the body into smaller segments. To do this uniformly, the body has been indentified into planes with special names.

  • The Sagittal Plane is a dividing line down the vertical length of the body running from front to back. This plane divides the body into left and right segments. When dividing the body into equal halves, this plane is referred to as the midsagittal plane.

  • The Frontal (Coronal) Plane is a dividing line that runs lengthwise from side to side. This plane divides the body into front and back regions, referred to as anterior and posterior portions.

  • The Transverse Plane is a horizonal plane that divides the body across into upper and lower sections.


APBodyPlanes.jpg

Body Cavities

The human body as a whole is made up of open spacies, called cavities, that contain well-ordered arrangements of the internal organs.
The two major body cavities are called the ventral and dorsal body cavities.

The Ventral Body Cavity:

  • The upper part of the ventral cavity inclues the thoracic cavity, which is commonly referred to as the chest cavity.
  • The midportion of the ventral cavity is a subdivision of the thoracic cavity called the mediastinum.
  • Other subdivisions of the ventral cavity are called the right and left plueral cavities.
  • The lower portion of the ventral cavity includes and abdominal cavity and a pelvic cavity. These two combined form one cavity, called the abdominopelvic cavity, because no physical partition divides them.

-- An actual physical partition divides the thoracic cavity from the abdominal cavity. This partition is a muscular sheet called the diaphragm, and it is the most important muscle used for breathing.


The Dorsal Body Cavity:

  • The dorsal body cavity contains the cranial cavity, including the skull and brain, as well as the spinal cavity, where the spinal cord is located.


APBodyCavities.png


To make it easier to locate the organs featured in the ventral cavity, anatomists have divided the large abdominopelvic cavity into four quadrants. These quadrants are divided by the midsagittal and transverse planes. These sections are commonly referred to as right upper, left upper, right lower, and left lower. This is a very simply way to identify portions of the abdominopelvic cavity, yet they are somewhat vague in locating specific organs. To divide the abdominopelvic cavity more precisely, it has also been subdivided into nine regions.

(AZ, unfinished)


Brittany

Body Regions

Axial Region- head, neck, torso, or trunk
Appendicular Region - upper and lower extremities


body_regions.jpg

The Balance of Body Functions :

Homeostasis - relative consistancy of the internal environment
Survival depends on the body maintaining relative constant conditions within the body
  • 1. The body uses negative feedback loops and, less often, positive feedback loops to maintain or restore homeostasis
  • 2. Feedback loops involve a sensor, a control center, and an effector

Feedback Loop - the basic type of control system in the body. A highly complex and integrated communication control network, classified as negative or positive.

  • Negative Feedback Loop - Homeostatic control system in which information feeding back to the control center causes the level of a variable to be changed in the direction opposite to that of the initial stimulus. ( Oppose, or negate, a change in a controlled environment. )
  • Positive Feedback Loop - Homeostatic control system in which information feeding back to the control center causes the level of a variable to be pushed farther in the direction of the original deviation, causing an amplification of the original stimulus. ( stimulatory. temporarily amplify or reinforce the change that is occuring. )

Developmental Processes - Changes and functions occuring during the early years
Aging Processes - Changes and functions occuring after young adulthood.

Chapter 3: Cells and Tissues

Section 1: Cells

pgs. 42-47


Size and Shape of the Cell:

  • Human cells all vary in size
  • All cells are microscopic and can only be seen through a microscope
  • Cells all differ in shape

Composition:

  • Cells contain a substance called cytoplasm. Cytoplasm is a substance that exists onlyin cells. It can also be referred to as "living matter"
  • Organelles are specialized structures within the cytoplasm
  • The cell interior is surrounded by a plasma membrane

Parts of the Cell:


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  • Plasma membrane-Surrounds the entire cell forming an outer boundary. It is composed of a thin, two layered membrane of phospholipids which contain protein. A diagram of plasma membrane can be found in your book on page 42, diagram 3-1.
  • Cytoplasm-Internal cell fluid and numerous organelles, these organelles consist of:
    • Ribosomes:
      • Made of two subunits of mostly ribosomal RNA
      • They may attach to rough ER or lie free in cytoplasm
      • They manufacture enzymes and other protein compounds
      • Synthesize proteins, also known as a cells "protein factory"
    • Endoplasmic reticulum (ER):
      • A network of connecting sacs and canals
      • They carry substances through fluid cytoplasm
      • There are two types, rough and smooth
      • Rough ER:
        • Collects, folds, and transports proteins
      • Smooth ER:
        • synthesizes chemicals to make new membranes
    • Golgi apparatus:
      • Group of flattened sacs near the nucleus
      • Golgi apparatus collects chemicals into vesicles that move from the smooth ER outward to the plasma membrane
      • "Packaging center"
    • Mitochondria:
      • It is composed of inner and outer membranous sacs
      • It is involved with energy-releasing chemical reactions
      • "Power Plants"of the cells
      • They contain one DNA molecule
      • Enzymes found in mitochondrial walls use oxygen to break down glucose and other nutrients to release energy, a process called aerobic or cellular respiration
    • Lysosomes:
      • "Bubble" of enzymes encased by membrane
      • Cell's "digestive system"
      • Protective function, they eat microbes
      • Formerly thought to be responsible for apoptosis
    • Centrioles:
      • Pair of hollow cylinders, each made up of tiny tubules that lie at right angles to each other near the nucleus
      • Function in cell reproduction
    • Microvilli:
      • Small fingerlike extensions of the plasma membrane
      • Increase absorbtion surface area of the cell
    • Cilia:
      • Fine hairlike extensions found on free or exposed surfaces of some cells
      • Some are found in groups and capable of moving in unison in a wavelike fashion
      • Single nonmoving cilia in some cells serve sensory functions
    • Flagella:
      • Single projections extending from cell surfaces
      • Much larger than cilia
      • "Tails" of sperm cells only example of flagella in humans

  • Nucleus:
    • Controls cell because if contains DNA, the genetic code:
      • Instructions for making proteins which in turn determine cell structure and function
    • Component structures include nuclear envelope, nucleoplasm, nucleolus, and chromatin granules

Relationship of cell Structure and Function:

  • Every human cell has a designated function. Some functions can include helping maintain the cell and some regulate the life process of the body itself.
  • Specialized functions of a cell differ depending on number and type of organelles.





Movements of Substances Through Cell Membranes

Membranes must permit certain substances to enter the cell and allow others to leave. These transport processes are classified under two general headings:


  • Passive transport processes
  • Active transport processes


  • The primary passive transportprocesses that moves substances through the cell membranes include the following:

      • Diffusion
      • Osmosis
      • Dialysis
      • Filtration







c8x16types-transport.jpg

Scientists describe the movement of substances in passive systems as going "down a concentration gradient." This means that substances in passive systems move from a region of high concentration to a region of low concentration until they reach equal proportions on both sides of the membrane.
      • Diffusion- Process by which substances scatter themselves evenly through an available space. This system does not require additional energy to establish this distribution of substances.
      • Osmosis and Dialysis - diffusion occures across a selectively permeable membrane. It permits certain substancesbut not others across the permeable membrane. Osmosis is the diffusion of water but not solutes. Dialysis is diffusion of solutes (substance disolved into another substance).
      • Filtration - The movement of water and solutes through a membrane as a result of a pushing force that is greater on one side of the membrane than on the other side. The force is call hydrostatic pressure, which is simply the force or weight of a fluid pushing against some surface. Ex. Blood pressure, blood pushes against vessel walls.

Active transport is the uphill movement of a substance through a living cell membrane. Uphill means "up a concentration gradient." That is from a lower to a higher concentration. The energy required for this movement is obtained from ATP (adenosine triphophate).

    • Ion pump
      • An ion pump is protein complex in cell membrane.
      • Ion pumps use energy from ATP to move substances across cell membranes against their concentration gradients.
      • some ion pumps work with other carriers so that glucose or amino acids aretransported along with ions.

    • Phagocytosis and Pinocytosis
      • Both are active transport mechanisms because they require cell energy.
      • Phagocytosis is a protective mechanism often used to destroy bacteria.
      • Pinocytosis is used to incorporate fluids or dissolved substances into cell.

Cell Transport and Diseases
Several very severe diseases result from damage to the cell transport processes. Two examples are Cystic fibrosis (CF) and Cholera.

    • Cystic fibrosis is an inherited condition in which chloride ion (CI-) pumps in the plasma membrane are missing. Because the chloride ion transport is altered, the cells that rely heavily on chloride transporters may die and their remains then thicken the secretions of many exocrine glands. When abnormally thick mucus goes into the lungs it impairs normal breathing and frequently leads to recurring lung infections. Because of the difficulty with breathing and digestion and other problems caused by the disease the body does not develope normally. Digestion is compromised by thick pancreatic secretions and thereby prevent important disgestive juices from flowing into the intestins.






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    • Cholera is a bacterial infection that causes cells ining the intestines to leak chloride ions. Water follows chloride ions out of the cells by osmosis, causing severe diarrhea and the resulting loss of water by the body. Death can occur in a few hours if treatment is not received.




Belinda-- pg. 73-74 "tissues"

Tissues:

  1. Epithelial tissue
  • Covers body and lines body cavities
  • Cells packed closely together with little matrix
  • Classified by shape(squamous, cubodial, and transversal) and arrangement (simple or stratified) of cells
  1. Connective Tissue
  • Most abundant tissue in the body
  • Types:
    • Areolar connective tissue
    • Adipose, fat tissue
    • Fibrous connective tissue
    • Bone
    • Cartilage
    • Blood
    • Hematopoietic tissue
  1. Muscle Tissue
  • Skeletal muscle tissue
  • Cardiac muscle tissue
  • Smooth muscle tissue
  1. Nervous Tissue
  • Function: rapid communication between body structures and control of body functions.
  • Glia- supportive and connecting cells


Chapter 6: The Integumentary System and Body Membranes

"Classification of Body Membranes"
  • Classification of body membranes:
    • Epithelial membranes-composed of epithelial tissue and an underlying layer of connective tissue
    • Connective tissue membranes- composed exclusively of various types of connective tissue
  • Epithelial membranes:
    • Cutaneous membrane- the skin
    • Serous membranes- simple squamous epithelium on a connective tissue basement membrane
      • parietal- line walls of body cavities
      • visceral- cover organs found in body cavities
      • examples:
        • pleura- parietal and visceral layers line walls of thoracic cavity and cover the lungs
        • peritoneum- parietal and visceral layers line walls of abdominal cavity and cover the organs in that cavity
      • diseases
        • pleurisy- inflammation of the serous membranes that line the chest cavity and cover the lungs
        • peritonitis- imflammation of the serous membranes in the abdominal cavity that line the walls and cover the abdominal organ
      • Mucous membranes:
        • line body surfaces that open directly to the exterior
        • produces mucus, a thick secretion that keeps the membranes soft and moist
  • Connective tissue membranes:
    • do not contain epithelial components
    • produce a lubricant called synovial fluid
    • examples are the synovial membranes in the lining of the bursal sacs


membranes.jpg


Structure of the Skin
‍Skin--- sheet-like organ that covers the entire body and acts as a barrier, also known as the Cutaneous Membrane
‍---The skin is made up of two layers: Epidermis and Dermis
  • Epidermis- the outermost layer composed of a thin layer of stratified squamous epithelium
  • Dermis- deeper of the two layers, thicker than epidermis and is mainly made up of connective tissue
---The Epidermis and Dermis are supported by a thick layer of loose connective tissue and fat called Subcutaneous tissue or the Hypodermis
  • Insulates the body
  • Serves as a stored source of energy and can be used as a food source is needed
  • Acts as a shock-absorbing pad
  • Protects underlying tissues from injury

--Epidermis
  • Arranged in distinct layers of tightly packed epithelial cells
  1. Stratum germinativum -- inner most layer, cells undergo mitosis and reproduce themselves, new cells move towards the surface of the skin. New skin “specializes”it’s self to provide protection for the body. This process allows the skin to repair its self and maintains an effective barrier against infection and injury.
      • Keratin- protein substance that makes skin waterproof and provides protection to abrasions.
      • Also called the pigment layer it is responsible for the production of melanin. Melanin gives skin it’s color. The pigment-producing cells are called melanocytes.


  1. Stratum corneum – Tough outermost layer of the skin, cells filled with keratin are constantly pushed towards the surface, dead cells are constantly “flaking” off and replaced by new cells.

--Other key terms:
  • Cyanosis—a condition that occurs when blood oxygen level decreases or if actual blood flow reduces dramatically and turns the skin a bluish gray color
  • Vitiligo—a condition characterized by patchy looking areas of light skin resulting from acquired loss of epidermal melanocytes.
  • Albanism—hereditary condition characterized by a partial or total lack of melanin pigment in the skin and eyes.
  • Areolae—area around nipple, 70-75% of pregnant women develop blotchy areas of brown pigment over forehead, cheeks, nose, upper lip, or chin.
  • Freckle—common variant of normal skin pigmentation characterized by a small light brown or red spot, freckles are small flat macules.
  • Blister—may occur due to burns, friction burns, or exposure to irritants.
  • Dermal-epidermal junction—junction that exists between the dermis and epidermis

--Dermis
  • Deeper than epidermis and much thicker than epidermis
  • Composed largely of connective tissue
  • Unlike epidermis cells are scattered apart with many fibers in between (collagen, elastic fibers).
  • Upper region of dermis is characterized by parallel rows of peglike projections called Dermal papillae which helps to bind the skin layers together. thumbprints.
  • The connective tissue also contains a network of nerves and nerve endings to process sensory information.
  • Developmental malformation of dermal blood vessels can result in birthmarks
    • Strawberry hemangioma—collection of dilated vessels that may appear like a bruise at birth but then grows rapidly into a red nodule. Most shrink, fade, or disappear completely.
    • Port-wine stain—permanent and will not go away
    • “Stork-bite”—occurs due to dilation of dermal capillaries at the nape of the neck during development resulting in a birth mark.

  • The deeper area of dermis is filled with interlacing collagen fibers, which gives toughness, and some elastic fibers, which allows the skin to stretch.
    • In pregnant women skin on the stomach may stretch beyond the skin’s ability cause “stretch marks” called striae



skin.jpg

Appendages of the Skin

  • Hair:
    • Soft hair of fetus and newborn is called lanugo
    • Hair growth requires epidermal tubelike structure called the hair follicle
    • Hair growth begins from hair papilla
    • Hair root lies hidden in follicle; visible part of hair is called the shaft
    • Alopecia- hair loss
    • Arrector pilli- specialized smooth muscle that produces "goose pimples" and causes hair to stand up straight
  • Receptors:
    • Specialized nerve endings make it possible for skin to act as a sense organ
    • Tactile (Meissner) corpuscle is capable of detecting light touch
    • Lamellar (Pacini) corpuscle is capable of detecting pressure
  • Skin glands:

  • Sweat Gland

  • Sudoriferous and sebaceous

    • Sweat, or sudoriferous glands

      • Eccrine sweat glands:

        • Most numerous, important, and wide-spread of the sweat glands

        • Produce perspiration or sweat, which flows out through pores on skin surface

        • Function throughout life and assist in body head regulation

      • Apocrine Sweat Glands:

        • Found primarily in axilla and around genitalia

        • Secrete a thicker, milky secretion quite different from eccrine perspiration

        • Breakdown of secretion by skin bacteria produces odor

      • Sebaceous Glands:

        • Secrete oil, or sebum, for hair and skin

        • Level of secretion increases during adolescence

        • Amount of secretion regulated by sex hormones

        • Sebum in sebaceous gland ducts may darken to form a blackhead

        • Acne vulgaris-inflamation of sebaceous gland duct



sn7_sweat_glands.jpg





Amber--pg 157 "C"

C. Functions of the Skin

Protection -- First Line of Defense
  1. Against infection by microbes
  2. Against ultraviolet rays from sun
  3. Against harmful chemicals
  4. Against cuts and tears
  5. Bruising can cause discoloration of skin as blood release from damaged vessels breaks down
  6. Skin grafts may be needed to replace skin destroyed by disease or trauma

Temperature Regulation
  1. Skin can release almost 3000 calories of body heat per day
  2. Mechanisms of temperature regulation -- (1) Regulation of sweat secretion, (2) Regulation of flow of blood close to the body surface.

Sense organ activity
  1. Receptors serve as receivers for the body, keeping it informed of changes in its environment.
  2. Skin can detect sensations of light, touch, pressure, pain, heat, and color.
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Aneesah--pg. 157 "disorders of the skin-- A"

Disorders of the Skin

Any disorder of the skin can be called a dermatosis, which simply means "skin condition". Many dermatoses involve infalmmation of the skin, or dermatitis. A lesion is any measurable variation from the normal structure of a tissue. Lesions are not necessarily signs of kisease; they may be benign variations that do not constitute a disorder. Freckles are considered lesions but are not a sign of a disease. Side angle observations with a penlight is a method used to determine the category of a lesion:

    • elevated - casts shadows outside their edges

    • flat- do not cast shadows
    • depressed - cast shadows inside their edges

Lesions are distinguished by abnormal density of tissue or abnormal coloration. Overgrowth or deficient growth of skin cells, calcification, and edema can cause changes in skin density. discoloration can result from overproduction or underproduction of skin pigmen ts such as the increase in melanin seen in a mole. A decrease in blood flow or oxygen content can give the skin a bluish cast (cyanosis). An increase in blood flow or oxygen content can give a red or darker hue to the skin. Discoloration of the affected area is associated with most skin lesions. Some of the most common lesions are from scrapes and cuts. As a result of out skin repairing itself the replaced fibrous tissue is denser than the original tissue. Sometimes producing a scar while also providing extra stregnth in case of further injury.

Skin Repair: First, clotting of blood stops blood loss. Then cells of stratum germinativum produce more epithelial cells to rebuild the epidermis as the clot dissolves. At the same time fiber-producing cells of the dermis replace torn collagen fibers.


















































BURNS:

Treatment and recovery or survival, depend on total area involved and severity and depth of the burn.

Classification of burns:

burn-classification.jpg

First-degree burns ( partial thickness burn )

  • Only surface area of epidermis involved

  • Causes minor discomfort and some reddening of the skin

  • Although the surface layers of the epidermis may peel in 1-3 days, no blistering occurs, and actual tissue destruction is minimal

First-Degree-Burn.jpg

Second-degree burns ( partial thickness burn )

  • Involves the deep epidermal layers and always causes injury to the upper layers of the dermis

  • Deep second-degree burns damage sweat glands, hair follicles, and sebaceous glands, complete destruction to the dermis does not occur

  • Blisters, severe pain, generalized swelling, and fluid loss characterize this type of burn

  • Scarring is common

Second-Degree-Burn.jpg

Third-degree burns ( full thickness burn )

  • Characterized by complete destruction of the epidermis and dermis

  • Tissue death extends below the primary skin layers into the subcutaneous tissue

third_degree_burn.jpg

Fourth-degree burns ( full thickness burn)

  • Extends below the subcutaneous tissue to reach the muscle or bone

  • Such injuries may occur as a result of high-coltage electrical burns or by exposure to very intense heat overtime

  • Treatment may require extensive skin grafting, and even amputation of limbs

4th_degree_burn_.jpg

One distinction between partial thickness burns and full thickness burns is that full thickness lesions are insensitive tp pain immediately after injury because of the destruction of nerve endings; however, intense pain occurs soon there after. Circulatory shock, fluid imbalances, respiratory injury, and infections are common complications to serious burns.

Rule of Nines :

One of the most fequently used methons of determining the extent of a burn injury. With this technique the body is divided into 11 ares of 9% each. with the area around the genitals representing the additional 1% of the body surface area. In the adult 9% of the skin covers the head and each upper extremity, including front and back surfaces. Twice as much, or 18%, of the total skin area covers the front and back of the trunk and each lower extremity, including front and back surfaces.
rule_of_nines_2.jpg



Skin Infections:

1. Impetigo- highly contagious staphylococcal or streptococcal infection. Starts with erythema (reddish discoloration) and develops into yellowish crusts.
2. Tinea- fungal infection of the skin. Example: ring worm, athlete's foot, and jock itch. Occasionally, fissures (cracks) occur.
3. Warts- caused by papillomavirus, type of benign neoplasm of the skin
4. Boils- AKA furuncles. A group of untreated boils fuse into even larger pus filled lesions called carbuncles.
5. Scabies- contagious skin condition caused by the itch mite.


Vascular and Inflammatory Skin Disorders


1. Decubitus ulcers- pressure or bed sores
2. Hives or urticaria- common condition characterized by raised red lesions called wheals.
3. Scleroderma- autoimmune disease that affects blood vessles and connective tissues of the skin
4. Psoriasis- chronic, common and often life long skin disease. Characterized by silvery white, scalelike plaques that remain fixed on the skin for months.
5. Eczema- most common inflammation. Characterized by inflammation that is often accompanied by papules, vesicles, and crusts.


E. Skin Cancer
  • Three common types
    • Suqamous cell carcinoma- most common type, characterizzed by hard, raised tumorsexternal image cc0804.08.rink.fig1.jpg
    • Basal call carcinoma- characterized by papules with a central crater; rarely spreadsexternal image img_0850.jpg
    • Melanoma- malignancy in a nevus (mole); the most serious type of skin cancerexternal image Melanoma_Asymmetry.jpg
  • The most important causative factor in common skin cancer is exposure to sunlight
    • Kaposi sarcoma, characterized by purple lesions, is associated with AIDS and other immune deficiencies
  • external image kaposissarcoma.jpg


Chapter 7: The Skeletal System
AZ, pg 200

Functions of the Skeletal System
  • Provides internal framework that supports the body.

  • Protects internal organs and helps fight disease by producing white blood cells.

  • Makes movement possible by working in concert with muscle contraction and relaxation.

  • Stores calcium, a vital resource.

  • Forms blood cells -- the process called hematopoiesis.







Types of Bones:

  • Four major types of bones:
    • Long:
      • example: femur or thighbone
    • Short:
      • example: carpal or wristbone
    • Flat::
      • example: parietal bone or skull
    • Irregular:
      • example: sphenoid bone from skull







bonestructure.jpg
bonestructure.jpg

  • Structure of long bones:
    • Diaphysis- shaft or hallow tube of hard compact bone
    • Medullary cavity- hollow space inside the diaphysis that contains yellow marrow
    • Epiphyses- ends of the bone made of spongy bone that contains red bone marrow
    • Articular cartilage- thin layer that covers each epiphysis; provides as a cushion
    • Periosteum- strong, fibrous membrane covering bone everywhere except at joint surfaces
    • Endosteum- thin membrane that lines medullary cavity
  • Structure of flat bones:
    • Thin layer of compact bone surrounding cancellous (spongy) bone are surrounded by bony trabeculae












longbonestructure.jpg
longbonestructure.jpg



Bone Formation and Growth

  • Bone Formation and Growth
  • Early bone development (before birth) consists of cartilage and fibrous structures
  • Cartilage models gradually replaced by calcified bone matrix - process called endochondral ossification
  • Osteoblasts form new bone, and osteoclasts resorb bone
  • Divisions of the Skeleton
    • Axial skeleton (80 bones)
    • skull
    • spine or vertebral column
    • thorax
    • Appendicular skeleton
  • upper extremities, including shoulder (pectoral) girdle
  • lower extremities, including hip (pelvic) girdle

bone_growth.jpg


brittany "differences between a man's and a woman's skeleton"

Size – Male skeleton generally larger

Shape of pelvis – male pelvis deep and narrow, female pelvis broad and shallow

Size of pelvis inlet – female pelvic inlet generally wider, normally large enough for baby’s head to pass through it

Pubic angle – angle between pubic bones of female generally wider


A man’s skeleton and woman’s skeleton differ in several ways. The female pelvis is made so that the body of a baby can pass through it during birth. Although the individual male hipbones (coxal bones) are generally larger than the individual female hipbones, together the male hipbones for a narrower structure then do the female hipbones. A man’s pelvis is shaped something like a funnel, but a woman’s pelvis has a broader, shallower shape, more like a basin. (incidentally, the word pelvis means “basin.” ) Another difference is that the pelvic inlet and pelvic outlet are both normally much wider in the female then in the male. The pubic angle at the front of the female pelvis where the two bones join is usually wider then it is in the male.


male_and_female_pelvis.jpg

Aneesha "joints"
Every bone in the body, except one, connects to at least one other bone. The exception is the hyoid bone which anchors the tongue. Joints hold our bones together securely and at the same time make it possible for movement to occure between the bones.

  • Joint Types:

    • Synarthroses
      • No movement - Joints that have fibrous connective tissue growing between the articulating (joining) bones holding them close together. Synarthroses do not allow any significant movement between the joined bones. The joints between cranial bones are synarthroses, commonly called sutures.
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    • Amphiarthroses
      • Slight movement - Joints in which cartilage connects the articulating bones. The symphysis pubis, the joint between the two pubic bones and the joints between the vertebrae are amphiarthrosis. In the vertebrae, these joints make it possible to flex the trunk forward or sideways and even to circumduct and rotate it. The central core of these intervertebral disks consists of a pulpy, elastic substance that loses some of its resiliency with age. Damage to a disk caused by the pressure of sudden exertion or injury may push its wall into the spinal cord. This conditions is known in laymans terms as a slipped disk. Medical professionals refer to it as a herniated disk.
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    • Diarthroses
      • Freely moving joints - The vast majority of our joints are diarthroses. These joints allow movement in many directions and sometimes in only one or two directions. Each diarthroses has a joint capsule, a joint cavity, and a layer of cartilage over the ends of the joined bones. The joint capsule is made of the body's strongest and toughest material, fibrous connective tissue and it lined with a smooth, slippery synovial membrane. The joiint capsule is attached to the periosteum (peri means "around" and osteon means "bone").
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Ligaments are cords or bands made of the same strong fibrous connective tissue as the joing capsule. Ligaments grow out of the periosteum and lash the two bones together even more firmly.

A layer of articular cartilage over the joint ends absorbs jolts. It also provides a smooth surface that enables the bones of a joint to move with little friction. The synovial membrane secretes a lubricating fluid (synovial fluid) that allows easier movement with less friction.

Types of Diarthrotic Joints

  • Ball and socket * a ball shaped head of one bone fits into a concave socket of another bone. Shoulder and hip joints are ball and socket joints Of all the joints in out bodies these permit the widest rang of movements.
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  • Hinge * hinge joints allow movement in only two directions, flexion (bending a joint) and extension (straightening it out). Elbows, knee and fingers are hinge joints.
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  • Pivot * a small projection of one bone pivots in an arch of another bone. The projection of the axis (the second vertebra in the neck), pivots in a arch of the atlas (the first vertebra in the neck). This rotatesthe head, which rest on the atlas.
external image images?q=tbn:ANd9GcTcmvCFZM-MNpCyZFKmXMhXeBqCJn7tYpR5o7wb6C_OoXOg7kju
  • Saddle joint * Only one pair of saddle joints exists in the body-between the metacarpal bone of each thumb and a carpal bone of the wrist (the carpal bone is called trapezium). We can flex, extend, abduct, adduct, and circumduct our thrmbs. We can also move our thumbs to touch the tip of any one of our fingers. this movement is called opposing the thumb to the fingers. Without the saddle joints, we couold not do simple acts such as picking up a pin or graping a pencil between thumb and forefinger.
external image images?q=tbn:ANd9GcR96mNfIay0OfB5PPyxGCrgBks_GFBIV0cBdKXTRiU5ohsVD-CCtQ
  • Gliding point * These joints are the least movable diarthrotic joints. Their flat articulating surfaces allow limited gliding movements, such as that the superior and inferior articulating processes between successive vertebrae.
external image images?q=tbn:ANd9GcT0pylbLVCqThX2ve8R7Tw26I8TLaGi-S9MAo_prp9YmOh3-a3f4A
  • Condyloid * Condyloid joints are those in which a condyle (an oval projection) fits into an elliptical socket. Example: The fit of the distal end of the radius into depressions in the carpal bones.
external image images?q=tbn:ANd9GcTOP5czbg6FvnpWMhPvkV1Yf90pI9ktF0j7Thm9UZoc6cs1tpN3Pw











Rebecca "skeletal disorde"--a, b, c, d

Skeletal Disorders


Tumors of Bone and Cartilage

  • Osteosarcoma- the most common and devastating malignant neoplasm of bone, very aggressive and destructive type of cancer. Most often occurs in the femur, tibia, and humerous. Treatment involves removal of tumors.
  • Chondrosarcoma- cancer of the skeletal hyaline cartilage tissue. The most common site of tumors involves the medullary cavity of the humerous, femur, ribs, and pelvic bones.

Metabolic Bone Diseases

  • Osteoporosis- Disorder in which bones lose minerals and become less dense. One of the most common and serious bones diseases. Occurs most often in elderly white women. Characterized by excessive loss of calcified bone matrix. Make bones brittle and very easy to fracture. Compression fractures in the vertebral column results in shortened stature called "dowager's hump."
  • Rickets and Osteomalacia- rickets in young children and osteomalacia in adults are metabolic skeletal diseases. Both diseases are characterized by demineralization from bone related to a Vitamin D deficiency. Vitamin D is important in Calcium absorption. Lack of minerals cause bowing of the legs and other skeletal developmental problems.
  • Paget Disease- AKA osteitis deformans. Characterized by localized, intermittent, and uncontrolled episodes of "frenzied" osteoclasts and osteoblasts. The faulty remodeling process results in deformed, unstable, and easily fractured bones.
  • Osteogenesis imperfecta- AKA brittle bone disease. The bones are brittle due to the lack of production of the organic matrix of bone, which suppresses the bone's ability to withstand twisting and compression forces without breaking.

Bone Infection

  • Osteomyelitis- general name for bacterial infections of bone and marrow tissue. Staphylococcusis the most common pathogen. Can occur after surgical procedure or open fracture.
  • Bones are also susceptible to viruses, fungi, and other pathogens.
Rickets
Rickets

Rickets

Paget disease
Paget disease

Paget Disease


Joint Disorders

Noninflammatory Joint Disorders
  • Does Not Involve inflammation of the synovial membrane and does not produce systemic (whole body) symptoms
  • Osteoarthritis- AKA degenerative joint disease. It is the most common noninflammatory disorder of movable joints. Characterized by abnormal formation of new bon (“bone spurs”) and degeneration of articular cartilage. Symptoms include localized tenderness, morning stiffness, and pain with movement.
    • Boucard nodes- common sign of osteoarthritis, nodes on proximal interphalangeal joints,
    • Heberden Nodes- common sign of osteoarthritis, nodes on the distal interphalangeal joints.
Inflammatory Joint Diseases (Arthritis)
  • Arthritis- General name for many different inflammatory joint diseases
    • Rheumatoid arthritis-type of autoimmune disease. Involves chronic inflammation of connective tissues. Begins in Synovial membranes and spreads to cartilage. Ulnar deviationis a common characteristic deformity of the hands. Because it is a systemic disorder fever, anemia, weight loss, and profound fatigue are common.
      • Juvenile rheumatoid arthritis- more sever than adult version. Destroys growth of cartilage and growth of bones stops.
    • Gouty arthritis (Gout)- Metabolic condition characterized by an increase of uric acid and nitrogen waste in blood. Excess uric acid deposits as sodium urate crystals in joints.
    • Infectious arthritis- a variety of pathogens can infect the synovial membrane. Lyme Disease, caused by spriochete bacterium carried by deer ticks, is characterized by inflammation in the knees or other joints and a varirty of systemic signs. Ehrilichiosis is caused by Ehrilichia bacteria, has many of the symptoms of Lyme disease but is must more prevalent.


Chapter 8: The Muscluar System


Introduction:
  • Muscular tissue enables the body and its parts to move
    • Movement caused by ability of muscle cells (fibers) to shorten or contract
    • Muscle cells shorten by converting chemical energy (obtained from food) into mechanical energy, which causes movement
    • Three types of muscle tissues exist in the body

    Muscle Tissue:

    • Skeletal Muscle: striated or voluntary muscle
      • 40% to 50% of body weight
        • "red meat" attached to bone
      • Microscopic reveals crosswise stripes, or striations
      • Contractions can be voluntarily controlled
    • Cardiac Muscle: composes bulk of heart
      • Cardiac muscle cells branch frequently
      • Characterized by unique dark bands called Intercalated disks
      • Interconnected nature of cardiac muscle cells allows heart to contract efficiently as a unit
    • Smooth Muscle: nonstriated involuntary or visceral muscle
      • Lacks cross stripes, or striations, when seen under a microscope; appears smooth
      • Found in walls of hollow visceral structures such as digestive tract, blood vessels, and ureters
      • Contractions not under voluntary control; movement caused by contraction is involuntary



  • moremuscletissue.jpg
    moremuscletissue.jpg




aneesha

Structure of Skeletal Muscle


Major structures

  1. Each skeletal muscle is an organ composed mainly of skeletal muscle cells and connective tissue.
  2. Most skeletal muscles extend from one bone across a joint to another bone
  3. Parts of a skeletal muscle:
  • Origin - attachment to the bone that remains relatively stationary or fixed when movement at the joint occurs
  • Insertion - point of attachment to the bone that moves when a muscle contracts
  • Body - main part of the muscle
external image images?q=tbn:ANd9GcTwy2c_crZeeQJFL0T9Y1uMjUDW0VGXNwcsiLOtMvzfhSPkJs29zQ
  1. Tendons - attach muscles to the bone (strong cords of fibrous connective tissue; some tendons are enclosed in synovial fluid; tubes are called tendon sheaths).
  2. Bursae - small synovial-lined sacs containing a small amount of synovial fluid; located between some tendons and underlying bones.

Microscopic structure and function
  1. Contractile cells, or muscle fibers-grouped into bundles and intricately arranged.
  2. Fibers contain thick myofilaments (containing the protein myosin) and thin myofilaments (composed of actin).
  3. Basic functional (contractile) unit called sarcomere:

  • Sarcomeres are separated from each other by dark bands called Z lines.
  • sliding filament model explains mechanism of contraction.
      • Thick and thin myofilaments slide past eaxh other as a muscle contracts
      • Contraction requires calcium and energy rich ATP molecules





























Functions of Skeletal Muscles

  • Movement
    • Muscles produce movement by pulling on bones as a muscle contracts
      • the insertion bone is pulled closer to the origin bone
      • movement occurs at the joint between the origin and the insertion
    • Groups of muscles usually contract to produce a single movement
      • Prime mover- muscle whose contraction is mainly responsible for producing a given movement
      • Synergist- muscle whose contractions help the prime mover produce a given movement
      • Antagonist- muscle whose actions oppose the action of a prime mover in any given movement


  • Posture
    • a type of muscle contraction, called tonic contraction, enables us to maintain body position
      • in a tonic contraction, only a few of a muscles fibers shorten at a time
      • tonic contractions produce no movement of body parts
      • tonic contractions maintain muscle tone called posture
    • Good posture (optimum body positioning) favors best body functioning
    • Skeletal muscle tone maintains posture by counteracting the force of gravity
  • C Heat production
  • Survival depends on the body's ability to maintain a constant body temperature
    • Fever- elevated body temperature- often a sign of illness
    • hypothermia- body temperature below normal
  • Contraction of muscle fibers produces most of the body heat required to maintain normal body temperature
  • Fatigue
    • Reduced strength of muscle contraction
    • Caused by repeated muscle stimulation without adequate periods of rest
    • repeated muscular contraction depletes cellular ATP stores and outstrips the ability of blood supply to replenish oxygen and provide nutrients
    • Contraction in the absence of adequate oxygen produces lactic acid, which contributes to muscle burning
    • Oxygen debt- term used to describe the metabolic effort required to burn excess lactic acid that may accumulate during prolonged periods of exercise
      • Labored breathing after strenuous exercise is required to "pay the debt"
      • This increased metabolism helps restore energy and oxygen reserves to pre-exercise levels


breathing2.jpg


Amber, Motor Unit & Muscle Stimulus

Motor Unit
Before a skeletal muscle can contract and pull on a bone to move it, the muscle must first be stimulated by nerve impulses. These muscle cells are stimulated by a nerve fiber called a motor neuron. The point of contact between the nerve ending and the muscle fiber is called a neuromuscular junction. Signal chemicals are released by the motor neuron in response to a nervous impulse. These chemicals then generate events within the muscle cell that result in contraction or shortening of the muscle cell. A single motor neuron, with the muscle cells it innervates, is called a motor unit.


Muscle Stimulus
In a laboratory setting, a single muscle fiber can be isolated and subjected to stimuli of varying intensities so that it can be studied. Such experiments show that a muscle fiber does not contract until an applied stimulus reaches a certain level of intensity. The minimal level of stimulation required to cause a fiber to contract is called the threshold stimulus.
When a muscle fiber is subjected to a threshold stimulus, it contracts completely. Because of this, muscle cells are said to respond “all or none.” However, a muscle is composed of many muscle cells that are controlled by different motor units and that have different threshold stimulus levels. Although each fiber in a muscle such as the biceps brachii responds in an all or none mode when subjected to a threshold stimulus, the muscle as a whole does not. This fact has tremendous importance in everyday life. It allows you to pick up a bottle of soda or a 30lb. child because different motor units can be activated for different loads. Once activated, however, each fiber always responds all or none.


Motor Unit ;
  1. Stimulation of a muscle by a nerve impulse is required before a muscle can shorten and produce movement.
  2. A motor neuron is the nerve cell that transmits an impulse to a muscle, causing contraction.
  3. A neuromuscular junction is the point of contact between a nerve ending and the muscle fiber it innervates.
  4. A motor unit is the combination of a motor neuron and the muscle cell or cells it innervates.

Muscle Stimulus ;
  1. A muscle will contract only if an applied stimulus reaches a certain minimal level of intensity—called the threshold stimulus.
  2. Once stimulated by a threshold stimulus, a muscle fiber will contract completely, a response called all or none.
  3. Different muscle fibers in a muscle are controlled by different motor units having different threshold-stimulus levels.
i. Although individual muscle fibers always respond in an all or none mode to a threshold stimulus, the muscle as a whole does not.
ii. Different motor units responding to different threshold stimuli permit a muscle as a whole to execute contractions of graded force.

Skeletal Muscle Groups :

external image head_neck_muscle.jpg
1.Muscles of the Head and Neck
  • Frontal Muscle - raise eyebrow
  • Orbicularis oris - kissing muscle
  • Zygomaticus - elevates cornor of lips(smiling muscle)
  • Mastication - closing mouth and chewing movement
    • Masseter - elevates mandible
    • Temporal - closes jaw
2. Muscles and move the upper extremeties ;
  • Pectoralis Major
  • Latissimus Dorsi
  • Deltoid
  • Biceps Brachii
  • Triceps Brachii

3. Muscles of the Trunk ;
  • External Oblique - outer most
  • Internal Oblique - middle layer
  • Tranversus external image human-body-muscle-diagram.jpg
    abdominis - inner most layer
  • Rectus Abdominis
  • Intercostal Muscles - between ribs
  • Diaphragm - Sperates Thoratic and Abdominal cavities

4. Muscles that move the Lower extremeties
  • Iliopsoas - flexor
  • Gluteus Maximus - extensor
  • Adductor Muscles - adductor
  • Hamstring muscles - flexor
    • Sememembranosus
    • Semitendinasus
    • Biceps Femoris
  • Quadriceps Femorous - extensor
  • Tibialis Anterior - dorsiflex
  • Gastrocnemius - plantar flexion
  • Peroneus group - 3 mucles - plantar flexio


Movements produces by Skeletal muscle ;

  • Flexion- Makes changes between two bones smaller.
  • Extension- Makes angle between two bones larger.
  • Abduction- Moving away from the midline (moving arm out to the side).
  • Adduction- Moving toward the midline (bringing arms down from elevated position).
  • Rotation- Movement around a longitudinal axis (rotation of head- shaking head no).
  • Circumduction- Moves a part so that its distal end moves in a circle (when a pitcher winds up).
  • Supination- Turning palms toward anterior.
  • Pronation- Tuening palms toward posterior.
  • Dorsiflexion- Foor elevates with toes poitns upward.
  • Plantar Flexion - Foor directed downwards, tip toes.
external image flexionextension.gifexternal image abductionadduction.gif
external image Elbow_pro-supi_rg_h.JPG external image 0199210896.dorsiflexion.1.jpg




Major Muscle Disorders

Myopathies- muscle disorder
1. Muscle Injury
  • - muscle strain, involve overstretching or tearing of muscle fibers.
  • Myalgia Sprain- injury in joint or damage to a ligament.
  • Myositis- any muscle inflammation
  • Fibromyositis- tendon inflammation with myositis
  • Cramps- painful muscle spasm
  • Contusion- muscle bruise
2. Muscular Dystrophy- group of genetic diseases characterized by atrophy of skeletal muscle tissue.
  • Duchenne muscular dystrophy (DMD)- most common form of muscular dystrophy. Muscle atrophy is masked by excessive replacement of muscle fat and fibrous tissue. DMD is characterized by mild leg muscle weakness that progresses rapidly to include shoulders
3. Myasthenia Gravis- chronic disease characterized by muscle weakness, especially in the face and throat. It is an autoimmune disease in which the immune system attacks muscle cells at the neuromuscular junction.

Chapter 9: The Nervous System

  • Organs and divisions of the Nervous System
  • Central nervous system (CNS)- brain and spinal cord

  • Automatic nervous system (ANS)
  • Cells of the nervous system
  • Neurons

      • sensory neurons: conduct impulses to the spinal cord and brain; also called afferent neurons
      • motor neurons: conduct impulses away from brain and spinal cord to muscles and glands; also called efferent neurons
      • interneurons: conduct impulses from sensory neurons to motor neurons; also called central or connecting neurons
  • Glia (neuroglia)
    • support cells, bringing the cells of nervous tissue together structurally and functionally
    • three main types of connective tissue cells of the CNS
      • astrocytes- star shaped cells that anchor small blood vessels to neurons
      • microglia- small cells that move in inflamed brain tissue carrying on phagocyosis
      • oligodendrocytes- form myelin sheaths on axons in the CNS (Schwann calls for myelin sheaths in PNS only)
  • Disorders of nervous tissue
    • multiple sclerosis- characterized by myelin loss in central nerve fibers and resulting conduction impairments
    • tumors
      • general name for nervous system tumors is neuroma
      • most neuromas are gliomas, glial tumors
      • multiple neurofibromatosis- characterized by numerous benign tumors
  • Nerves
  • Nerve- bundle of peripheral axons
    • tract- bundle of central axons
    • white matter- brain or cord tissue composed primarily of myelinated axons (tracts)
    • gray matter- brain or cord tissue composed primarily of cell bodies and unmylinated fibersaxon


  • Nerve coverings- fibrous connective tissue
    • endoneurium- surrounds individual fibers within a nerve
    • perineurium- surrounds a group (fascicle) of nerve fibers
    • epineurium- surrounds the entire nerve

nerve-11.gif


  • Reflex arcs
  • nerve impulses are conducted from receptors to effectors over neuron pathways or reflex arcs; conduction my a reflex arc results in a reflex (that is, contraction by a muscle or secretion by a gland)
  • the simplist reflex arcs are two- neuron arcs- consisting of sensory neurons synapsing in the spinal cord with motor neurons; threeneuron arcs consist of sensory neurons synapsing with the spinal cord with the interneurons that synapse with other neurons

300px-Patellar-knee-reflex.png




Aneesah: Nerve Impulses, The Synapse pg. 271

Nerve Impulses

Definition - self propagating wave of electrical distrubance that travles along the surface of a neuron membrane (sometimes called a action potentials).

Mechanism

      • At rest, the neuron's membrane is slightly positive on the outside - polarized - from a slight excess of Na+ on the outside
      • A stimulus triggers the opening of Na+ channels in ther plasma membrane of the neuron.
      • Inward movement of Na+ depolarizes the membrane by making the inside move positive than the outside at the stimulated point; this depolarizations is a nerve impulse (action potential).
      • The stimulated section of membrane immediately repolarizes, but by the time the depolarization has already triggered the next section of membrane to depolarize, thus propagating a wave of electrical disturbances (depolarizations) all the way down the membrane.
external image Figure-2.jpg

The Synapse

      • Definition - the place where impulses are transmitted from one neuron to another (postsynampit neuron
      • Synapse made of three structures: Synaptic know, synaptic cleft, and plasma membrane
      • Neurotransmitters bind to specific receptor molecules in the ;membrane of a postsynaptic neuron, opening ion channels and thereby stimulating impulse conduction by the membrane
      • Names of neurotransmitters - acetylcholine, catecholamines (norepinephrine, dopamine,and serotonin), endorphins, enkephalins, nitric oxide (NO), and other compounds.
      • Parkinson disease (PD) - characterized by abnormally low levels of dopamine in motor control areas of the brain; patients usually exhipit involuntary trembling and muscle rigidity.


Amber: Central Nervous System Section A pg. 272


Divisions of the Brain

1. Brainstem

a. Consists of, named in ascending order, the medulla oblongata, pons, and midbrain.

b. Structure--white matter with bits of gray matter scattered through it

c. Functions

(1) All three parts of brainstem are two-way conduction paths

(2) Sensory tracts in the brainstem conduct impulses to the higher parts of the brain

(3) Motor tracts conduct from the higher parts of the brain to the spinal cord

(4) Many important reflex centers lie in the brainstem

2. Cerebellum

a. Second largest part of the human brain

b. Helps control muscle contractions to produce coordinated movements so that we can maintain balance, move smoothly, and sustain normal postures.

c. Recent evidence shows the cerebellum also may have wider coordinating effects, assisting hte cerebrum and other regions of the brain.

3. Diencephalon

a. Structure and function of the hypothalamus

(1) Consists mainly of the posterior pituitary gland, pituitary stalk, and gray matter.

(2) Acts as the major center for controlling the ANS; therefore helps control the functioning of most internal organs.

(3) Controls hormone secretion by anterior and posterior pituitary glands; therefore it indirectly helps control hormone secretion by most other endocrine glands

(4) Contains centers for controlling appetite, wakefulness, pleasure, etc.

b. Structure and function of the thalamus

(1) Dumbbell-shaped mass of gray matter extending into each cerebral hemisphere

(2) Relays sensory impulses to cerebral cortex sensory areas

(3) In some way produces the emotions of pleasantness or unpleasantness associated with sensations

4. Cerebrum

a. Largest part of the human brain

b. Outer layer of gray matter is the cerebral cortex; made up of lobes; composed mainly of dendrites and cell bodies of neurons

c. Interior of the cerebrum composed mainly of white matter (that is nerve fibers arranged in bundles called tracts)

d. Functions of the cerebrum--mental processes of all types, including sensations, consciousness, memory, and voluntary control of movements.

ertjgdfgdf.jpg





  • Brain Disorders:

    • Destruction of brain tissue:
      • Cerebrovascular accident (CVA): Hemorrhage from or cessation of blood flow through cerebral blood vessels; a "stroke"
      • Cerebral palsy (CP): condition in which damage to motor control areas of the brain before, during, or shortly after birth causes paralysis (usually spastic) of one or more limbs
    • Dementia: syndrome that includes progressive loss of memory, shortened attention span, personality changes, reduced intellectual capacity, and motor control deficit
      • Alzheimer disease (AD): brain disorder of the middle and late adult years characterized by dementia
      • Huntington disease (HD): inherited disorder characterized by chorea (purposeless movement) progressing to severe dementia
      • HIV: also causes AIDS can infect neurons and thus cause dementia
      • Fig1-AIDS-damage.jpg
    • Seizure disorders:
      • Seizure: sudden burst of abnormal neuron activity that results in temporary changes in brain function
      • Epilepsy: many forms, all characterized by recurring seizures
      • Electroencephalogram: graphic representation of voltage changes in the brain used to evaluate brain activity


  • Spinal Cord:
    • Columns of white matter, composed of bundles of myelinated nerve fibers, form the outer portion of the H-shaped core of the spinal cord; bundles of axons called tracts
    • Interior composed of gray matter made up mainly of neuron dendrites and cell bodies
    • Spinal cord tracts provide two-way conduction paths, ascending and descending
    • Spinal cord functions as the primary center for all spinal cord reflexes; sensory tracts conduct impulses to the brain, and motor tracts conduct impulses from the brain
  • Coverings and Fluid Spaces of the Brain and Spinal Cord:
    • Coverings:
      • Cranial bones and vertebrae
      • Cerebral and spinal meninges, the dura mater, arachnoid mater, and the pia mater
    • Fluid spaces:
      • Subarachnoid spaces of meninges
      • Central canal inside cord
      • Ventricles in brain

spinal-meninges.jpg


Brittany: Peripheral Nervous System pg. 273
Peripheral Nervous System

Cranial nerves

  • Twelve pairs – attached to the undersurface of the brain
  • Connect brain with the neck and structures in the thorax and abdomen

Cranial_nerves.jpg

Spinal Nerves

  • Thirty-one pairs – contain dendrites of sensory neurons and axons of motor neurons
  • Conduct impulses necessary for sensations and voluntary movements
  • Skin surface area supplied by a single nerve is called a dermatome.

I10-13-spinal.jpg

Peripheral nerve disorders
1. Neuritis – general term referring to nerve inflammation
  • Sciatica in inflammation of the sciatic nerve that innervates the legs
  • Neuralgia, or muscle pain, often accompanies neuritis

2. Trigeminal neuralgia – recurring episodes of stabbing pain along one or more branches of the trigeminal (fifth cranial) nerve in the head

3. Bell palsy – paralysis of facial features resulting from damage to the facial (seventh cranial) nerve

4. Herpes zoster, or shingles
  • Viral infection caused by chickenpox virus that has invaded the dorsal root ganglion ad remained dormant until stress or reduced immunity precipitate an episode of shingles
  • Usually affects a single dermatome, producing characteristic painful plaques or vesicles.


Autonomic Nervous System
  • Functional anatomy:
    • Autonomic nervous system: motor neurons that conduct impulses from the central nervous system to cardiac muscle, smooth muscle, and glandular epithelial tissue; regulates the body’s automatic, or involuntary functionswyDiagramNervousSystem.jpg
    • Autonomic neurons: preganglionic autonomic neurons conduct from spinal cord or brainstem to an autonomic ganglion; postganglionic neurons conduct from autonomic ganglia to cardiac muscle, smooth muscle, and glandular epithelial tissueI10-13-nerves2.jpg
    • Autonomic or visceral effectors: tissues to which autonomic neurons conduct impulses (that is, cardiac and smooth muscle and glandular epithelial tissue)

500166-fx3.jpg
    • Composed of two divisions:
      • Sympathetic system
      • Parasympathetic system
      • Autonomic conductions paths:
        • Consist of two-neuron relays (that is, preganglionic neurons from the central nervous system to autonomic glanglia, synapses, postganglionic neurons from ganglia to visceral effectors)
        • In contrast, somatic motor neurons conduct all the way from the CNS to somatic effectors with no intervening synapses
        • Sympathetic nervous system:
          • Dendrites and cell bodies of sympathetic preganglionic neurons are located in the gray matter of the thoracic and upper lumbar segments of the spinal cord
          • Axons leave the spinal cord in the anterior roots of spinal nerves, extend to sympathetic, or collateral, ganglia and synapse with several postganglionic neurons whose axons extend to spinal or autonomic nerves to terminate in visceral effectors
          • A chain of sympathetic ganglia is in front of and at each side of the spinal column
          • Functions of the sympathetic nervous system:
            • Serves as the emergency or stress system, controlling visceral effectors during strenuous exercise and when strong emotions (anger, fear, hate, or anxiety) are elicited
            • Group of changes induced by sympathetic control is called the fight-or-flight response

sympathetic_vs_parasympathetic.jpg

Parasympathetic Nevous System


Structure:
  • Located in the gray matter of the brainstem and the sacray segments of the spinal cord
  • AKA craniosacral system
  • Parasysmpathetic ganglia located in the head and the thoracic and abdominal cavities close to visceral effectors
  • Each parasympathetic preganglionic neurons to a single effector
Function:
  • Involved in everyday conditions
  • Tends to slow heart beat, increase peristalis, and increase secretion of digestive juices and insulin

Autonomic Neurotransmitters

  • Sympathetic preganglionic axon, parasympathetic preganglionic axon and parasympathetic postganglioic axon release acetylcholine and are called cholinergic fibers.
  • Adrengic fibers are sympathetic postganglionic neurons which release norepinephrine.


external image 09_36.jpg

Autonomic Nervous System as a whole

  • The autonomic nervous system's function is to regulate the body's automatic, involuntary functions in ways that maintain homeostasis.
  • Influenced by the limbic system's (emotional brain- hypothalamus and parts of the cerebral cortex) impulses. Emotions can cause autonomic function change.

Disorders of the Autonomic Nervous System

  • Stress Induced Diseases
    1. Heart Disease
    2. Digestive probems-colitis(colon inflammation) and gastric ulcers.
    3. Reduced resistance to disease- Prolonged stress causes a weakening of the immune system allowing increased risk of infection
  • Neuroblastoma
    • Malignant tumor of the sympathetic nervous system and causes sympathetic symptoms like increased heart rate, excessive sweating, and high blood pressure. It most often occurs in young children.