11. Musculoskeletal System

Question 1

Know epimysium vs perimysium vs endomysium

Answer 1

Connects to tendon vs lining surrounding fascicle vs lining of muscle cell/myofiber

Question 2

Know sarcolemma vs sarcoplasm vs myofibril

Answer 2

cell membrane of myofiber vs cytoplasm of myofiber for smaller cell component of myofiber

Question 3

Know z line vs M line vs H zone vs A band vs I band vs sarcomere

Answer 3

squiggly thing vs midline vs just entire myosin aka thick filaments vs actin + myosin aka both thick and thin filaments vs just actin aka thin filaments vs region that covers z line to z line. Sarcomeres attached end to end make up myofibrils

Question 4

Know myosin, actin, tropomyosin and troponin mechanism for muscle contraction

Answer 4

Begins at neuromuscular junction: motor neurons release acetylcholine to bind to receptors on sarcolemma —> depolarization spreads to T tubules releasing Ca2+ —> high [Ca2+] in sarcoplasm –> troponin changes conformation –> tropomyosin changes conformation –> myosin can hop on actin’s next rung

Question 5

Axial vs appendicular skeleton

Answer 5

Basic body framework: skull, vertebral column, ribs, hyoid (bone that helps with swallowing), rib cage, ossicles vs bones for limbs, pectoral girdle (clavicle and scapula) and pelvis

Question 6

Perks of endoskeleton

Answer 6

support movement/provides framework, protects vital organs, stores calcium, hematopoiesis

Question 7

Flat bones vs long bones

Answer 7

ex: skull, ribs, pelvis; protects organs and hematopoiesis vs ex: femur, humerus; framework, movement, hematopoiesis in epiphysis. Both have inner spongy cancellous bones and and outer compact hard bones

Question 8

Diaphysis vs epiphysis vs metaphysis vs epiphyseal/growth plate

Answer 8

long part vs short part vs in between part vs plate within epiphysis for linear bone growth

Question 9

Where does hematopoiesis occur?

Answer 9

in bone marrow

Question 10

Red bone marrow vs yellow bone marrow

Answer 10

hematopoiesis (that’s why it’s red b/c it makes RBCs), found in flat bones and epiphysis of long bones vs fat storage and adipocytes, found at diaphysis of long bones

Question 11

Name and consistency of inner most bone vs outer most bone

Answer 11

spongy bone aka cancellous bone aka trabecular bone vs periosteum

Question 12

What surrounds spongy bone?

Answer 12

compact bone made up osteons aka Haversian systems

Question 13

What makes up Haversian system?

Answer 13

Haversian/central canal in center of layers, it contains blood vessels and nerves; lamellae = concentric layers surrounding central canal; canaliculi = tiny channels in b/w lamellae; lacunae = empty spaces occupied by osteocytes

Question 14

How do osteocytes/bone cells in lacunae communicate and transport nutrients?

Answer 14

via gap junctions

Question 15

What are Volkmann’s canals?

Answer 15

Perpendicular to Haversian canals, they carry their own set of blood vessels

Question 16

What makes up the bone matrix?

Answer 16

organic osteoid made up of proteins osteocalcin and osteopontin to give tensile strength and Type I collagen, and inorganic hydroxyapatite made up of calcium phosphate crystals to give rigid strength

Question 17

Osteoprogenitor cells vs osteoblasts vs osteocytes vs osteoclasts

Answer 17

precursor to osteoblasts, contain growth factors to let them mature to osteoblasts vs synthesize collagen, osteocalcin and osteopontin to build bone, alkaline phosphatase synthesize hydroxyapatite vs bone cells that occupy lacunae and maintain bone vs in charge of bone resorption/breakdown, tartrate resistant acid phosphatase, occupy Howship’s lacunae, derived from monocytes

Question 18

Tendons vs ligaments

Answer 18

Connects muscle to bone vs connects bone to bone

Question 19

What is cartilage and describe 3 types of cartilage? What about articular cartilage?

Answer 19

Avascular connective tissue secreted by chondrocytes. Hyaline - in larynx and trachea, reduce friction and absorb shock; elastic - in outer ear and epiglottis, shape and support; fibrous - intervertebral discs, pubic symphysis (where 2 pelvic bones meet in middle), rigidity and absorb shock. Articular cartilage - made up of hyaline cartilage that line the surfaces of bone in joints to prevent bones from making contact w/ e/o

Question 20

What are chondrocytes?

Answer 20

Secrete fibrous materials like collagen and elastin that give cartilage its strength and flexibility (collagen = fibrous protein found in cartilage); derived from fibroblasts

Question 21

What’s a joint and name 3 types?

Answer 21

where bone meets bone. Synarthroses - stiff/immoveable, skull; amphiarthroses - slightly stiff and a little moveable, intervertebral discs; diarthroses/synovial joints - contain synovium/synovial membrane that secrete synovial fluid (to lubricate joint movement) in joint/articulate cavity, the synovial capsule that surrounds the entire joint, ball and socket (moveable all around like shoulders and hips), hinge (moves in one plane like elbows and knees)

Question 22

What happens in high osteoblast activity vs high osteoclast activity?

Answer 22

Ca2+ and PO43- move from blood to bone vs Ca2+ and PO43- move from bone to blood

Question 23

What does parathyroid hormone (PTH), calcitonin, and calcitriol (vit D) do? What about intestinal/renal absorption of Ca?

Answer 23

high PTH and calcitriol –> high osteoclast activity –> high intestinal/renal absorption of Ca; high calcitonin –> high osteoblast activity –> low intestinal/renal absorption of Ca

Question 24

Tetany vs tonus vs twitch vs tremor vs frequency summation

Answer 24

continuous full contraction vs continuous partial contraction vs spasm vs involuntary quivering vs addition of multiple simple twitches before fully relaxing

Question 25

What does sarcomere look like in muscle contraction?

Answer 25

A band stays same (ie. Actin and myosin don’t change in length during muscle contraction); H, I, Z and M distances are smaller

Question 26

Sarcoplasmic reticulum aka SR

Answer 26

a modified ER with lots of Ca2+ ions. Covers myofibrils. Contains transverse tubule aka T tubule that triggers release of Ca ions from SR

Question 27

Know different names of muscle cell

Answer 27

Myocyte aka myofiber. Muscles cells contain myofibrils which consist of sarcomeres

Question 28

Differences between skeletal, smooth and cardiac muscles

Answer 28

Know which ones are voluntary, nucleated, spindle-shaped, striated, branched. Smooth and cardiac have myogenic activity (can contract without neural input) and are controlled by autonomic nervous system. Skeletal muscle has red slow twitch (Type I) fibers doing oxidative phosphorylation and white fast twitch (Type IIb) fibers doing anaerobic metabolism (like glycolysis). Cardiac muscle has intercalated discs containing gap junctions

Question 29

Where can muscle get energy to stall O2 debt and fatigue?

Answer 29

Creatine phosphate and myoglobin

Question 30

Endochondral ossification vs intramembranous ossification

Answer 30

Hardening of cartilage transformed into bone like most long bones vs undifferentiated embryonic connective tissue (mesenchymal tissue) transformed into bone like the skull

Question 31

Antagonistic vs synergistic muscles

Answer 31

Muscles working in opposite directions for same function: one muscle contracts while other muscle relaxes (like biceps, triceps, elbow) vs working together to do same function

Question 32

Flexor vs extensor vs abductor vs adductor muscles. Medial vs lateral rotation

Answer 32

Dec angle across a joint like biceps vs inc angle across a joint like triceps vs moving a body part away from midline like deltoid vs moving a body part towards midline like pecs. Rotates axis of limb toward midline vs rotates axis of limb away from midline