Learn: Exam 2 - Anatomy and Physiology of domestic animals

Identify the major functions of the skeletal system

Protection

Movement

Storage of minerals

Support

Blood cell production

Why would each bone in your body be classified as an organ?

It consists of everything that an organ has. Bone consists of multiple types of tissues that work together to perform a movement.

Distinguish between axial and appendicular skeleton

Axial: bones made up of the main axis of the body ( sternum, parietal bone, mandible, zygomatic bone, atlas, ribs)

Appendicular: Makes up the limbs and appendages ( tibia, radius, femur, metatarsal, humerus, scapula, phalanges, patella).

Both: pelvis and pubis

Classify bones according to their shapes

Irregular bone: no "standard" shape (vertebrae)

Long bones: long shaft & complex shapes (femur)

Short bones: short & boxy (carpals)

Flat bones: parallel surfaces, flattened (rib)

Sesamoid bones: small "sesame seed" shaped (patella)

Identify the parts of a typical long bone, including the locations of compact and spongy bone

Compare compact and spongy bone (introduction; to be continued)

Spongy bone: looks like a sponge but built like scaffolding

Spaced filled with bone marrow

Found in the middle of bones

Porous tubular network

Compact bone: looks soild with no visble spaces

Optimized for strength and hardness

Edges of all bones and in shaft of long bones

Dense, organized in oestons.

Similarities

Made of bone tissse

Contains blood vessels, nerves, and bone marrow

Provide strength and protection

Name and describe the function of the four cell types associated with bone

Osteoblast: makes new bone (build)

convert cartilage to bone

Osteoclast: Breaks down bone (crash)

removes and remodels bone matrix

Osteoprogenitor cell: gives rise to osteoblasts

function repair

Osteocyte: mature bone cell, monitors bony matrix

maintains protein and mineral content

osteoprogenitor —> osteoblast —> osteocyte

——————

osteoclasts

Describe the general structure of compact bone, including osteons, canaliculi, etc.

Summarize the steps of endochondral ossification during early bone development

1. A complete cartilage model of the bone develops: chondrocytes enlarge and die, leaving cavities within the cartilage

2. Blood vessels grow around the outside of the cartilage and convert other cells into osteoblasts

3.Blood vessels and osteoblasts penetrate the diaphysis of the cartilage and create the primary ossification center

4.The medullary cavity is created as cartilage is replaced with bone (compact and spongy)

5. Capillaries and osteoblasts migrate into epiphyses that can create additional ossification center

Describe the two ways that bones develop in a young animal: appositional growth and bone lengthening (from course notes)

Osteoblasts break down bone in the medullary cavity.

Osteoblasts add bone to outer surfaces (circumferential lamellae)

*bone lengthening*

Discuss the role of growth hormone, IGFs, androgens, and estrogens in bone growth (course notes)

Describe calcium homeostasis and the interaction of the intestines, kidneys, and bone cells in this process for PTH

*When your calcium blood levels are too low, the parathyroid glands will release PTH into your blood to return your calcium levels to normal*

Describe calcium homeostasis and the interaction of the intestines, kidneys, and bone cells in this process for calcitonin

*When your calcium blood levels are too high, the thyroid glans will release calcitonin into your blood to return your calcium levels to normal*

Define parturient paresis and discuss the causes, symptoms and treatments

Also known as milk fevers is when cows cannot mobilize enough calcium postpartum (usually)

Causes

Low dietary calcium

Low PTH Problem with PTH receptor on bone , intestines, and kidneys

Symptoms

Loss of appetite

Muscle weakness especially in hind legs Decreased body temp Coma + death

Treatments

Iv'ing calcium carbonate Bovikalc

Describe the different types of bone fractures and how bones are repaired.

Closed/simple: Skin over fracture is unbroken

Open/compound: Projected through skin

Steps

1. Formation of a fracture hematoma

2. Formulation of an internal callus and external callus

3. Replacement of cartilage of the external callus with bone

4.Remodeling over time and completion with repair

List the functions of skeletal muscle

Produce skeletal movement

Maintain posture and body position

Support soft tissues

Guards' entrances and exits

Maintains body temp

Provide nutrient reserves

Describe the origin and organization of skeletal muscle at the tissue level

Identify the structural components of a sarcomere and differentiate between thin and thick filament structures (lines and bands)

H-band: Thick

M-Line: Thick

Sacromere: Both thick and thin

A-band: Both thick and thin

I-band: Thin

Z-line: Thin

Zone of overlap: Both thick and thin

Describe the process by which calcium is released by sarcoplasm

1. Action potential sweeps down the membrane, including t-tubules

2. T-tubules are in contact with SR membrane

3. Change in voltage from action potential opens calcium channels

4. Calcium from the SR is released into the sacroplasm.

What are 3 ways the sliding filament theory can "break down"?

1. Damage to actin or myosin filments

2. Lack of ATP

3. Lack of stimulation at the NMJ

Describe the sliding filament theory and explain the steps involved in skeletal muscle contraction

a. Calcium arrives at zone of overlap

b. Calcium binds to troponin causing the active-site on actin to be exposed

c. Myosin head binds to actin

d. Myosin head release ADP+P which causes the myosin head to pivot

e. A new ATP molecule binds to the myosin head and causes it to release from the actin

f. The myosin head is reactivated when ATP is converted to ADP+P

Describe the processes by which muscle fibers obtain the energy to power contractions.

Creatine phosphate *no oxygen*, produces 1 ATP

- ATP + Creatin

Anaerobic respiration *no oxygen, produces 2 ATP + 2 lactic acids

Muscle glycogen --> glucose --> 2 ATP + 2 pyruvic acid --> 2 lactic acid

Why is ATP necessary?

1. Cross bridge formation

2. Pumping calcium into SR

3. Na + K in and out of cells during action potential

Describe the factors that contribute to muscle fatigue

Inability of muscle to contact after prolonged activity

-Inadequate release of calcium from SR.

-Depletion of creatine phosphate

-Insufficient oxygen

-Depletion of glycogen

-The build-up of lactic acid

Explain some of the physiologic factors responsible for muscle hypertrophy, atrophy, and paralysis

Muscle hypertrophy: Increase in muscle size

Muscle atrophy: Decrease in muscle size

Paralysis: loss of muscle function