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Flashcards in Musculoskeletal Deck (76):
1

t-tubules of skeletal muscle are extensions of what?

the sarcolemma

2

an 'a' band within a skeletal muscle fiber contains what?

actin and myosin filaments

3

what role does calcium play in muscle contraction?

it binds to troponin allowing exposure of the actin binding sites

4

compared to skeletal muscle cells, cardiac muscle cells are?

autonomic

5

what are the characteristics of muscle?

excitability, contractibility, extensibility, and elasticity

6

what are the primary functions of muscle?

provide motion, maintain posture, and generate heat

7

what are the types of muscle?

skeletal, cardiac and smooth

8

multiple nuclei and long fiber like shape; very long and very thin

skeletal muscle - voluntary, ambulation of skeleton

9

one nuclei, tapered ends and spindle shaped

smooth muscle - involuntary, based on needs of the body

10

one nuclei with a branching network of cells and intercalated disks connecting cells

cardiac muscle - involuntary

11

well-defined group of cells surrounded by fibrous connective sheath

epimysium

12

attach to bones by fibrous tissue bands

tendons

13

attach to bones or muscles by broad sheets of fibrous tissue

aponeuroses

14

the most prominent aponeuroses that runs lengthwise between the muscles on an animal's ventral midline

linea alba

15

more stable site, does not move when muscle contracts

origin of muscle attachement

16

site that undergoes the most movement when a muscle contracts

insertion site of muscle attachement

17

why are origin/insertion sites important?

to determine if either is the cause of an immobile of painful joint, and they are used as a guide in surgery, cutting, retraction or used in closure or can be affected by the procedure

18

types of skeletal muscle actions

- agonist
- antagonist
- synergist
- fixator

19

directly produces a desired movement

agonist aka prime mover

20

directly opposes the action of the agonist

antagonist

21

contracts at the same time as agonist to assist its action

synergist

22

stabilizes joint to allow other movements

fixator

23

hold components of muscle fibers together, contain blood vessels and nerves, and are continuous with tendons or aponeuroses

connective tissue layers

24

order of muscle structure

outside in:
- epimysium
- perimysium
- endomysium
- fascicles
- muscle fiber
- myofibril

25

fibrous outside layer composed of tough collagen fibers that enclose everything else

epimysium

26

composed of reticular fibers and thick collagen fibers; separates groups of fascicles

perimysium

27

composed of fine, reticular fibers; separates individual fascicles within their groups

endomysium

28

groups of muscle fibers

fascicles

29

composed of myofibrils; multinucleate

muscle fibers

30

form interior muscle fibers; made up of many protein filaments; many sacromeres lined up end to end equals one

myofibrils

31

muscle cell membrane

sarcolemma

32

a storage organelle for calcium ions

sarcoplasmic reticulum

33

the basic contracting unit of skeletal muscle

sarcomere

34

what are the two primary protein filaments responsible for contraction?

thick, dark myosin and thin, light actin

35

a disc on each end of a sarcomere; discs can be shared among sarcomeres

z line/disc

36

light colored bands of a sarcomere made up of thin actin filaments

i bands

37

where the thick myosin filaments and thin actin filaments overlap

a bands

38

the light colored area located in the middle of the a band, made up of only myosin filaments with no overlapping actin

h bands

39

where the terminal portion of a motor neuron axon meets a muscle cell membrane, separated by a synaptic cleft

neuromuscular junction

40

what neurotransmitter is contained in the synaptic vesicles at the end of nerve fibers?

acetylcholine

41

one nerve fiber and all the muscle fibers it innervates

motor unit

42

if its a small, delicate movement of muscles

its a few muscle fibers per motor unit

43

if its a large, powerful movement of muscles

its a huge number of muscle fibers per motor unit

44

shortening of all sarcomeres in a muscle fiber

muscle contraction

45

when stimulated, individual muscle fibers contract completely or not at all

all or nothing principle

46

a single muscle fiber contraction; contractions out of sync with each other

twitch contraction

47

ATP provides energy to allow sliding of actin and myosin filaments, ATP converts to ADP and back to ATP, catabolism of glucose and oxygen help produce ATP and CP

chemistry of muscle contraction

48

creatinine phosphate; helps convert ADP back to ATP

CP

49

when ATP has one phosphate group split off

ADP - adenosine diphosphate

50

glucose stored in muscle

glycogen

51

oxygen stored in muscle attached to large protein molecules; red in color and can release oxygen to resupply the muscle fiber when needed

myoglobin

52

spasmodic muscle contractions that increase heat production

shivering

53

mechanisms to eliminate excess heat

panting or sweating

54

a system of communication that fasten cardiac muscle cells together

intercalated disks

55

cardiac muscle contractions

rapid and wavelike; contract with no external stimulation

56

part of the cardiac conduction system; located in the wall of the right atrium; generates impulse to start each heartbeat

sinoatrial node aka SA node

57

nerve supply to cardiac muscle

does not need to initiate contractions

58

sympathetic nervous system to cardiac muscle

stimulates heart in fight or flight response when an animal feels threatened

59

parasympathetic nervous system to cardiac muscle

inhibits cardiac function, making the heart beat slower when it is at rest

60

smooth muscle main forms

- visceral
- multi-unit

61

visceral smooth muscle

large sheets of cells in walls of some hollow organs like the bladder or gi tract; contracts in large waves and without external stimulation

62

multi-unit smooth muscle

small, discrete groups of cells found where small delicate contractions are needed like iris, blood vessels, lungs; contraction requires impulses from autonomic nervous system

63

actin and myosin filaments arranged as small contractile units that crisscross the cell

smooth muscle anatomy

64

sympathetic nervous system to smooth muscle

decreases activity to move blood to heart and skeletal muscles and away from urinary and gi tract for intense physical activity

65

parasympathetic nervous system to smooth muscle

increases activity when animal is relaxed and resting to help supply nutrients

66

atp use in the muscle cell is required to what?

- energize the power stroke of the myosin cross bridge
- disconnect the myosin cross bridge from the binding site on acting after the power stroke
- provide energy to the calcium ion pump to restore calcium in the cisternae of the sarcoplasmic reticulum

67

composed of adenine nucleotide with two additional phosphate groups attached by a high energy bond

atp

68

a considerable release of energy from atp, occurs when a terminal high-energy bond is broken by a hydrolytic enzyme produces adp and phosphate

atp hydrolysis

69

occurs via hydrolysis of creatine phosphate (cp)

atp synthesis

70

what is used for energy by a muscle cell and also used in the production of atp?

glucose

71

what are the end products when glucose is broken down by glycolysis?

- 2 atp and 2 molecules nadh that produce 4 atp molecules
- 2 pyruvic acid molecules

72

pyruvic acid, with the help of electrons carrying enzyme nadh, convert pyruvic acid to lactic acid by adding a phosphate molecule to glucose

anaerobic metabolism

73

oxygen for this process is available directly from the blood or from myoglobin

aerobic metabolism

74

enlarged areas of the sarcoplasmic reticulum surrounding the transverse tubules.; regions within the muscle cell store calcium in turn increase the capacity of the sarcoplasmic reticulum to release calcium

terminal cisternae

75

deep cavity of the sarcolemma, which allow depolarization of the membrane to quickly penetrate to the interior of the cell

t-tubules

76

latent twitch, contraction, and relaxation

muscle twitch phases