HOSA Vet - Chapters 3 & 4 1/2

  1. Musculoskeletal System Functions

    1. Functions

      1. structure

      2. leverage

      3. protection

      4. mineral reserves

      5. blood cell production

  2. Bone Structure

    1. Parts of a bone

      1. Cortical bone - outer layer of dense, compact bone

      2. Spongy/cancellous bone - found within long bones but not flat ones, made of tiny spicules to maximize strength, spongy arrangement keeps bones light

      3. Medullary Cavity - hollow center of the bone

      4. Bone Marrow - lies within the medullary cavity, produces blood cells

      5. Periosteum - outer layer of connective tissue, blends bones into other muscle and bones

      6. Bones are made of 30% organic material, 70% inorganic

        1. Made mostly of calcium and phosphorous (inorganic)

        2. Made of collagen fibers, polysaccharides, and cells (organic)

    2. Three Types of Bone Cells

      1. Osteoblasts

        1. lay down collagen matrix

        2. important for healing fractures

      2. Osteocytes

        1. responsible for maintaining the bone matrix

        2. they are mature osteoblasts

      3. Osteoclasts

        1. large cells that release minerals from the bone

    3. Osteoporosis

      1. when bones lose their normal density

      2. decrease in bone mass

  3. Joint Types and Movements

    1. Fibrous Joints

      1. little movement is allowed

      2. connected by dense connective tissue

      3. ex: skull (suture)

    2. Cartilage Joints

      1. bones are connected via cartilage

      2. ex: growth plate of young animals that will be replaced with bone

    3. Synovial Joints

      1. true, moveable joints

      2. lined with a membrane that produces synovial fluid; which provides lubrication and nutrients to the cartilage

      3. ligament - connects bone to bone

      4. tendon - connects muscle to bone

        1. can increase stability of a joint

    4. Meniscus

      1. hard cartilage pad 

      2. acts as a cushion between the bone ends

    5. Movement of Joints

      1. flexion - angle of bones gets smaller

      2. extension - angle of bones gets larger

      3. hinge joint - movement in one axis (elbow)

      4. pivot joint - rotation around a point

      5. ellipsoid joint - allows both hinge and rotation motions (wrist)

      6. ball and socket joint - allows movement in any direction 

  4. Axial and Appendicular Skeletons

    1. Axial Skeleton

      1. skull

        1. “cranium”

        2. protects fragile brain

      2. vertebrae

      3. ribs

      4. sternum

    2. Vertebrae

      1. Cervical vertebrae

        1. vertebrae that make up the neck

      2. Thoracic vertebrae

        1. one set of ribs for every thoracic vertebrae

        2. middle section 

        3. crucial for forming the ribs and protecting lungs

      3. Lumbar vertebrae

        1. located in the lower back

        2. flexes and extends so that the animal can run and walk

        3. supports organs

      4. Sacral vertebrae

        1. support the pelvis

        2. only 3 vertebra 

      5. Caudal vertebrae

        1. form the tail

    3. Appendicular Skeleton (forelimbs and hind limbs)

      1. Scapula

        1.  lies flat against the ribcage

        2. connects with muscles = makes it very flexible

          1. useful in cats (falling from tall heights)

      2. Forelimb (thoracic limbs)

        1. humerus - upper part of the forelimb

        2. humerus joins at the elbow with the radius and ulna

      3. Carpal bones

        1. carpus = human wrist

        2. drastic differences in carpal bones between species

          1. cats and dogs have four very long metacarpal bones and one very small, horses only have one large metacarpal bone (cannon bone)

        3. carpal → metacarpals → phalanges

      4. Toes

        1. number of toes = number of metacarpal bones

        2. the last phalanx is covered by the nail

      5. Pelvic limb

        1. forms a bony connection w/ the spine

        2. ilium, ischium, pubis

      6. Hind Limb

        1. femur = humerus of the back leg

        2. tibia = radius of the back leg, main weight bearing bone on the back leg

        3. fibula = ulna of the back leg

        4. CCL = cranial cruciate ligament - when tissue between the femur and tibia deteriorates, vets will slide the tibia and if it slides enough that’s how they know it’s CCL

      7. Tarsal Bones

        1. t = toes = tarsal

        2. arranged the same as carpal bones

        3. hock joint = carpus (ankle)

  5. Bone Growth and Remodeling

    1. Growth plates are responsible for bone elongation

    2. Ossification 

      1. when cartilage is replaced with bone (includes minerals, structure, blood supply, cells)

      2. happens as the growth plate of a young mammal advances

      3. injury may happen if a premature closure of the growth plate ensues in a young animal

    3. Radiographs (x-rays)

      1. tissues will appear on the radiograph

  6. Relation of Bones, Muscles, and Movement

    1. Together, bones and muscles provide the ability to move

    2. Tendon - muscle to bone

    3. Ligament - bone to bone

    4. Muscles are arranged in groups to achieve a single function

      1. this is called the agonist muscle

      2. antagonist muscle = opposite movement


Chapter 4 - The Circulatory System

  1. Blood Components and Functions

    1. Plasma

      1. transparent fluid that is part of blood

      2. mainly water (91-94%)

      3. combination of nutrients, electrolytes, hormones, metabolic wastes

      4. also made of proteins:

albumin

  1. maintains water in the bloodstream

globulins

  1. produce antibodies to protect against diseases

  2. high globulin levels = animal has likely been exposed to the disease

fibrinogen 

  1. aids in clotting blood

  2. when a blood vessel in damaged, it converts to fibrin which forms fibrous threads and attaches to the damaged vessel

  1. Red Blood Cells (erythrocytes)

    1. carry oxygen

    2. mature rbcs don’t have nucleus’

    3. biconcave shape - allows for efficient exchange of oxygen 

    4. produced in the bone marrow (erythropoiesis)

    5. constantly being replaced

    6. erythropoietin is the hormone produced by the kidney when it detects low oxygen levels, indicating for more rbcs to be made

    7. contains hemoglobin (can carry total of 4 oxygen molecules

    8. red because it contains iron

    9. hemoglobin carries 97% of the oxygen

  2. Carbon Monoxide

    1. very toxic because it prevents hemoglobin from delivering oxygen to the tissues