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mcat bio textbook > ch. 11 > Flashcards

ch. 11 Flashcards

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1
Q

name the three muscle tissues we have and what NS does it follow

A
  1. skeletal: somatic NS (voluntary)
  2. cardiac: only in heart ANS) (involuntary)
  3. smooth muscle: lines our organs on the inside (ANS) (involuntary)
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2
Q

skeletal muscles are attached how on the bone? they are connected by what structure? define

A

skeletal muscles are attached at two ends and are connected by tendons: strong connective tissue made up of collagen

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3
Q

how can skeletal muscles move a joint (four ways)

A

they can move by flexing (small angle) or extending (big angle). by either abducting (moving away from body) or adducting (moving toward the body)

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4
Q

what is the origin

A

the point where the bone is attached to the muscle closest to the body

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5
Q

what is the muscle insertion

A

the point where the bone is attached to the muscle farthest to the body

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6
Q

muscle movement occurs when

A

one muscle contracts and one muscle relaxes

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7
Q

what is an antagonistic muscle pair

A

muscles that move in opposite directions, tricep relaxes and bicep contracts

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8
Q

what is a synergistic muscle

A

muscles that move in same direction

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9
Q

what is a fascicle?

A

a connective tissue that holds contractile muscle together to allow flexibility in the muscle

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10
Q

what is a myofiber?

A

myofiber is a bundle of single skeletal muscle cells

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11
Q

what is the nucleus activity of skeletal muscle cell? how are they innervated?

A

they have multiple nuclei that came from fusion of cells from development and theyre innervated by one nerve

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12
Q

what are myofibrils

A

which is a specialized organelle that causes striated look and generates contractile force

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13
Q

what is the sequence of muscle cell anatomy from smallest to biggest

A

smallest: myofibrils to myofibers to fasicle : biggest

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14
Q

what are the proteins that generate contraction in myofibrils? what are their respective thickness? what is a overlapping of these proteins?

A

actin are thin filaments while myosin are thick filaments and the overlapping is called a sarcomere

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15
Q

each sarcomeres are bound by what lines? parts of overlapping is called what?

A

sarcomere is bound by 2 z lines where actin binds to this but myosin is not. the overlapping of actin and myosin filaments are called A band

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16
Q

parts with no actin are called? parts with no myosin are called?

A

no actin: is called H zone and no myosin: is called I zone

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17
Q

what occurs in the sarcomeres when contraction occurs? what powers this?

A

thin and think filaments slide across each other bringing the z lines closer together. this is powered by atp by enzyme myosin

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18
Q

actin and myosin are bound by what when contraction occurs?

A

cross bridge

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19
Q

what are the steps of contractile cycle

A
  1. myosin head binds to myosin binding site on actin called a cross bridge formation, atp is bound here
  2. the power stroke occurs when myosin head moves and pulls the actin chain toward the center and ADP is released
  3. to release actin from myosin head, a new ATP needs to be present.
  4. ATP hydrolysis occurs and myosin head is cocked back to start again
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20
Q

what is rigor mortus?

A

when a power stroke occurs but theres no more ATP to cause the release of the myosin head from actin

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21
Q

what is the troponin-tropomyosin complex? what stimulates it?

A

a complex that has tropomyosin a protein that blocks all the myosin binding sites on actin. and troponin is another protein that when bound to tropomyosin causes it to expose all the myosin binding sites. It is stimulated by increased levels of Ca2+

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22
Q

what is the neuromuscular joint? what is the NT used here?

A

NMJ is the synapse between the axon terminus and the myofiber and NT used is ACH

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23
Q

AP in muscle opens what channels? what is depol of the muscle clalled?

A

it opens calcium channels and the depol is called end plate potential and any small amount of ACH could cause a mini EEP

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24
Q

what structure helps AP’s get into cells?
what is the sarcoplasmic reticulum?

A

transverse tubules.
SR has special smooth ER that holds Ca2+ for AP

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25
Q

the smallest contraction is called? NS can increase force of contraction by?

A

the smallest contraction is a twitch. NS can increase force by 1. motor unit recruitment and 2. frequency summation

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26
Q

motor unit recruitment

A

a motor unit is a group of myofibers. NS can innervate many motor units to active them to increase force on contraction.

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27
Q

frequency summation

A

adding fast contractions since it doesnt allow calcium levels to go down and cause more contraction force

28
Q

what are the muscle fiber types?

A
  1. Slow twitch (red slow)
  2. Type IIa (intermediate/oxidative)
  3. Type IIb
29
Q

Slow twitch/red slow characteristics

A

speed is slow. force is low. has many mitochondria. very good blood flow. and has very high fatigue resistance (hours)

30
Q

Type iia characteristics

A

speed is medium. force is medium. has some mitochondria. medium blood flow. medium fatigue resistance (30 mins)

31
Q

type iib characteristics

A

speed: very fast. force is high. mito: very few. low blood flow. and low fatigue resistance (1 min)

32
Q

what are the similarities of cardiac and skeletal muscle cells

A
  1. also has sarcomeres that causes striated look
  2. T-tubules present
  3. uses troponin-tropomyosin complex
  4. also has long and short segments
33
Q

what are the difference of cardiac and skeletal muscle cells

A
  1. cardiac cells have one nucleus and skeletal have multiple
  2. cardiac cells have gap junctions
  3. cardiac calcium source is extracellular while Skeletal source is intracellular
  4. cardiac is controlled by ANS
  5. Ap in cardiac needs sodium and calcium channels which cause longer depol
34
Q

what are the similarities of smooth muscle and skeletal muscle cells

A
  1. contraction is done by actin and myosin
  2. triggered by influx of ca2+
  3. they dont branch out
35
Q

what are the difference of smooth and skeletal muscle cells

A
  1. smooth is shorter and narrow
  2. t tubules are not present
  3. not striated
  4. smooth has one nucleus and gap junctions
  5. troponin isnt used while calmodulin is used
  6. smooth uses extra cell calcium
  7. AP varies on location of smooth muscle
  8. long contractions by ANS
  9. constant fluctuation of RMP
36
Q

what is calmodulin and myosin light chain kinase?

A

the regulation of contraction where calmodulin binds calcium and causes phosphorylation of myosin to cause contraction (MLCK),like troponin tropomyosin complex but for smooth muscle, doesnt use troponin but uses calmodulin

37
Q

vertebrates have what kind of skeleton? what does it do?

A

endoskeleton that supports body, frames movement, protects organs, and provides calcium

38
Q

the endoskeleton is divided into

A

axial: skull, vertebral column, and rib cage
appendicular: everything else

39
Q

bone is what kind of tissue? where do these cells come from

A

they are connective tissue and come from fibroblasts that make collagen and elastin

40
Q

what other cells come from fibroblasts

A

adipocytes (fat), chondrocytes (cartilage) and osteocytes (bone cells)

41
Q

connective tissue is made up of

A

extracellular material called the matrix with some cells scatter around and ground substances

42
Q

there are two types of connective tissue, define them

A

loose connective tissue: includes fat cells and packing tissue
dense connective tissue: tissues with large amount of fibers like tendons, ligaments, and bone

43
Q

what tissues hold two bones together

A

ligaments

44
Q

what are the two bone shapes? name the shaft of the bone and the ends of the bone.

A

theres flat bones (skull, ribs) and long bones (leg and arm bones). the shaft is called diaphysis and ends is called epiphysis

45
Q

bones can be what two things? define them

A

compact (dense) or spongy: always surrounded by a compact bone

46
Q

what is bone marrow? what are the two types? define them

A

bone marrow is non bony material found inside of diaphysis of compact bones and in pores of spongy bones. there red marrow that makes RBC and yellow marrow made of fat

47
Q

what is inside anatomy of spongy bone?

A

they have spikes of bone within called spicules of trabeculae

48
Q

what is inside anatomy of compact bone?

A

base unit is called osteons that has a osteon hole/canal that holds blood, nerves, and lymph. surrounding the canal is lamellae.

49
Q

what are the central space inside the osteon canels?

A

they are launae where osteocytes or mature bone cells exists.

50
Q

cartilage is made up of what cells? name the three types?

A

made up of chondrocytes. the three are hyaline, elastic, and fibrous

51
Q

hyaline cartilage

A

strong and somewhat flexible found in trachea and larynx

52
Q

elastic cartilage

A

found in outer ear and other places that need support and more flexible

53
Q

fibrous cartilage

A

very rigid and found in places where very strong support is needed

54
Q

what is the blood flow into cartilage

A

they do not have blood therefore takes longer to heal

55
Q

movable joints have what fluid in between

A

synovial fluid

56
Q

what are the three joints of ligaments

A

immovable (points where bones fused), slight moveable, and freely moveable

57
Q

most bone growth occurs by? how

A

endochondral ossification where hyaline cartilage is made and replaced by bone

58
Q

kids have what kind of plate?

A

epiphyseal plate made of hyaline cartilage in between diaphysis and epiphysis and once we become adults, this plate causes fusion of the bones called epiphyseal line

59
Q

bone doesnt elongate what occurs?

A

they are remade in remodeling

60
Q

osteoblast function

A

laydown collagen until its surrounded by bone

61
Q

osteocyte function

A

after osteoblast lay down cartilage, it turns into mature bone cell or osteocyte

62
Q

osteoclast function

A

destroys bone to start remodeling

63
Q

PTH causes what to

A

stimulates osteoclast activity where kidneys and intestines absorb ca2+
Promotes remodeling

64
Q

calcitriol causes what to bone

A

may stimulate osteoclasts but minor. kidneys reabsorb Po2- and intestines still absorb calcium

65
Q

calcitonin causes what to bone

A

inhibits osteoclast activity and kidneys decrease calcium absorption

mcat bio textbook (10 decks)

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