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MCAT Bio > Muscular and Skeletal System (Chp 11) > Flashcards

Muscular and Skeletal System (Chp 11) Flashcards

1
Q

skeletal muscle

A

Function: voluntary muscle - contracts in response to conscious intent
Location: on the bone
Appearance: striated

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2
Q

cardiac muscle

A

found only in wall of the heart

striated

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3
Q

smooth muscle

A

found in walls of all hollow organs (GI tract, urinary system, uterus, etc) - no conscious control bc they are only innervated by autonomic nervous system

involuntary
unstriated
uninucleate

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4
Q

(3) muscle types

A

skeletal
cardiac
smooth

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5
Q

tendons

A

attach muscles to bones

strong connective tissue formed primarily of collagen

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6
Q

Ways skeletal muscle moves (4)

A
  1. flexing - decreasing angle of joint
  2. extending - increasing angle of joint
  3. abducting - moving away from body’s midline
  4. adducting - moving toward body’s midline
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7
Q

origin vs insertion (muscle)

A 
origin = point where muscle attaches to bone 
insertion = point where muscle attaches to bone more distant from the center of the body
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8
Q

antagonistic

A

muscles that are responsible for movement in opposite directions

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9
Q

synergistic

A

muscles that move a joint in the same direction

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10
Q

fascicles

A

bundles of connective tissues that holds contractile tissue together (bundles of myofibers)

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11
Q

myofiber

A

muscle cell

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12
Q

myofibrils

A

small units within myofiber (strings of sacromere)

>gives striated appearance

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13
Q

proteins in myofibril that generate contraction

A

actin (thin filaments) and myosin (thick filaments)

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14
Q

steps of contractile cycle

A
  1. cross bridge formation - myosin head binds to myosin binding site on actin (ADP and P bound)
  2. power stroke - myosin head moves to low E conformation and pulls actin chain toward center of sarcomere (ADP released)
  3. new ATP binds for release of actin by the myosin head
  4. ATY hydrolysis occurs and myosin head is cocked (high E conformation)
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15
Q

neuromuscular junction

A

synapse between an axon terminus (synaptic knob) and a myofiber

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16
Q

acetylcholinesterase

A

hydrolyzes ACh to choline and acetyl unit

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17
Q

(2) ways to increase force of contraction (via nervous system)

A
  1. motor unit recruitment

2. frequency summation -

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18
Q

Muscle fiber types

A
  1. Slow twitch fibers

2. fast twitch fibers

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19
Q

Type 1 Slow twitch fibers

A

aka red slow twitch or red oxidative fibers because of high myoglobin content and have better blood supply than fast twitch fibers > allow to maintain contraction for extended periods without fatigue

  • slow contraction
  • low force generated
  • high mitochondria
  • v dense capillaries
  • high fatigue resistance

(these are the fibers that allow marathoners to run for hours)

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20
Q

Type 2 Fast twitch fibers

A

two subcategories

  1. Type II A - fast twitch oxidative fibers - somewhat resistant to fatigue
    - intermediate contraction
    - medium force generated
    - some mitochondria
    - medium capillaries
    - medium fatigue resistance (30 mins)
  2. Type II B - white fast twitch fibers - due to lack of mitochondira these contract very quickly with great force BUT fatigue very quickly (1 minute)
    - very fast contraction
    - high force generated
    - very few mitochondria
    - v few capillaries
    - low fatigue resistance (1 min)
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21
Q

hematopoiesis

A

synthesis of formed elements of the blood (red blood cells, white blood cells. platelets)

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22
Q

vertebrate endoskeleton components

A

axial - skull, vertebral column, rib cage

appendicular - all other bones

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23
Q

bone is an example of _____

A

connective tissue

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24
Q

types of connective tissue

A

loose - packing tissues (areolar tissue and adipose tissue)

dense - contain large amounts of fiber (tendons, ligaments, cartilage, and bone)

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25
primary bone shapes
1. flat (scapular, ribs, skull) - location of hematopoiesis and important for protection of organs 2. long (limbs) - important for support and movement
26
long bone anatomy
epiphysis - flared end of bone -contains spongey bone - contains red bone marrow diaphysis - main shaft of long bone -contains medullary cavity - contains yellow bone marrow (fat)
27
bone marrow
non-bony material found in shafts of long bones and in pores of spongy bones
28
red marrow
found in spongey bone within flat bones = site of hematopoiesis (activity increases in response to erythroprotein)
29
yellow marrow
found in shafts of long bone - filled with fat and is inactive
30
ingredients of bone
1. collagen | 2. hydroxyapatite - solid material consisting of calcium phosphate crystals
31
ligaments
connect bone to other bone
32
tendons
connect bone to muscle
33
joint
point where one bone meets another
34
synarthroses
immovable joints - where bones are fused together | ex: skull
35
amphiarthroses
slightly movable joints - provide movability and support | ex: vertebral joints
36
diarthroses
freely movable joints - all are supported by ligaments | ex: ball and socket
37
synovial fluid
lubricate movable joints
38
endochondral ossification
hyaline cartilage is produced and then replaced by bone
39
intramembranous ossification
synthesis of bone from an embryonic tissue called mesenchyme
40
osteoblasts
cells that make bone by laying down collagen and hydroxyapatite -synthesize bone until it is surrounded by bone > now called an osteocyte and space it resides in is called a lacuna
41
PTH (parathyroid hormone)
- stimulates osteoclast activity - effect on kidney: increases reabsorption of calcium and stimulates conversion of vitamin D into calcitriol - effect on intestines: indirectly (via calcitriol) increases intestinal calcium absorption >stimulates bone breakdown >increases blood calcium
42
Calcitriol
effect on bones: may stimulate osteoclast activity (but minor) effect on kidney: increases reabsorption of phosphorous, decreases CA effect on intestines: increases absorption of CA >stimulates bone formation >decreased blood calcium
43
calcitonin
effect on bones: inhibits osteoclast activity | effect on kidneys: decrease reabsorption of calcium
44
osteoclast
continually destroy bone by dissolving hydroxyapatite
45
actin
think filament
46
myosin
thick filament
47
muscle heirarchy
protein filaments (actin and myosin) > sarcomere (unite of contraction) > myofibril (string of sarcomeres) > muscle cell (bundle of myofibrils) > fascicle (bundle of muscle cells > while muscle
48
sarcomere regions
H: just myosin I: just actin A: overlap of myosin and actin and just myosin section H and I region decreased during muscle contraction
49
what is characteristic of power stroke in muscle contraction
release of ADP > myosin returns to low E state common mistake is that this uses ATP when it doesn't
50
in absence of ATP muscle can't ___
relax think of rigor mortitis
51
muscle excitation-contraction coupling
dependent on CA - tropomyacin - covers myocin binding site on actin - troponin - when bound to CA causes conformational change on tropomyacin that reveals myocin binding sites >myosin binds to actin > contraction
52
Muscle E sources (3)
1. creatine + ADP > creating + ATP (short and explosive) 2. glycolysis > 2 net ATP and lactic acid (3-4 minutes) 3. aerobic respiration > 30 ATP, CO2, and H20 (slow but most E)
53
hemoglobin shifts L/R when Bohr conditions present
Right increased CO2 increased T decreased pH CO2 + H2O = H2CO3 = H+ + HCO3-
54
"___"-blast
immature cell that still divides produces matrix ex: osteoblast (bone) and condroblast (cartilage)
55
"____"-cyte
mature cell that usually doesn't divide | maintains matrix
56
matrix components
fibers - collogen - strong - elastic - recoil glob (ground substance) - liquid (blood plasma) - solid (bone)
57
osteon
``` unit of compact bone cross section shows: -bone in concentric rings -central canal -osteocytes - dormant not dead >needs waste exchange> has elaborate tunnel system between each other and central canal forming caniculi ```
58
describe inspiration during ventilation
contract diaphragm > increases size of chest cavity > decreases pressure >air rushes in
59
describe relaxed expiration of ventilation
relax diaphragm > decrease chest cavity size > increase pressure > air pushed out
60
skin layers
1. epidermis - made of epithelial tissue 2. dermis - connective tissue 3. hypodermis - fat
61
epidermis
made of epithelial tissue | top layer
62
dermis
connective tissues of skin
63
hypodermis
fat layer of skin
64
thermoregulation when cold weather
no sweat shiver vasoconstriction - diverts blood to core and away from skin surface
65
thermoregulation when hot weather
activate sweat glands to cool body with evaporative cooling no shivering vasodilation - bring blood to surface
66
sarcoplasmic reticulum
storage unit for calcium
67
alveolar pnuemocytes
type 1 - walls of alveoli | type 2 - produce surfactant (soapy substance) that reduces surface tension > keeps alveoli open

MCAT Bio (6 decks)

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