Muscular System Flashcards Preview

Biology > Muscular System > Flashcards

Flashcards in Muscular System Deck (69)
0

Types of Muscle

Smooth Muscle
Cardiac Muscle
Skeletal Muscle

1

Smooth Muscle

Narrow cylindrical fibers, non-striated, uninucleate; occurs in walls of internal organs; is involuntary;

2

Cardiac Muscle

Has striated, branched, generally uninucleated fibers; occurs in walls of heart; is involuntary;

3

Skeletal Muscle

Has striated, tubular, multinucleated fibers; is usually attached to skeleton; is voluntary.

4

Functions of the Muscular System

Support the body
Allow for movement of bones and other structures
Help maintain constant body temperature
Assist in movement of fluids in cardiovascular and lymphatic vessels
Protect

5

Bursa

Fluid filled sacs that provide cushioning between tendons and bones

6

Tendon

The connective tissue that connects muscle to bone

7

Origin

Attachment of a muscle to a stationary bone

8

Insertion

Attachment of a muscle on a bone that moves

9

Prime Mover

Does most of the work when moving

10

Synergist

Assists the prime mover

11

Antagonist

Works against the prime mover - purpose is to undo what was done by the prime mover

12

Muscles are named based on what seven characteristics?

Size
Shape
Location
Direction of fibers
Attachment
Number of attachments
Action

13

Do muscles pull or push?

Pull

14

T-tubule (transverse)

Portion of sarcolemma that penetrates muscle cells.

15

Sarcoplasmic Reticulum

Smooth endoplasmic reticulum that stores Ca+

16

Sarcolemma

Plasma membrane

17

Sarcoplasm

Cytoplasm

18

Sarcomere

One contracting unit of the muscle cell; made of the proteins actin and myosin

19

Actin

thin filaments

20

Myosin

Thick filaments shaped like a golf club

21

I Band

Region on a sarcomere where actin but no myosin is

22

H zone

Region where myosin is but no actin

23

A band

Length of the myosin fiber

24

How do filaments go over one another during muscle contraction?

Filaments slide over one another - do NOT crunch up!

25

First step of ATP in cellular work of motion...

ATP is split when myosin head is unattached (so becomes ADP)

26

Second step of ATP in cellular work of motion

ADP + P are bound to myosin as myosin head attaches to actin

27

Third step of ATP in cellular work of motion

Upon ADP+P release, power stroke occurs; head bends and pulls actin

28

Fourth step of ATP in cellular work of motion

Binding of fresh ATP causes myosin head to return to resting position

29

Power Stroke

Movement of myosin head to pull actin

30

Troponin

Calcium complex that modifies the position of tropomyosin

31

First step of Muscle Fiber Contraction

Nerve impulses (action potential) travels down motor neurons to a neuromuscular junction

32

Neuromuscular Junction

Where a motor neuron connects to skeletal muscle

33

Motor unit

A nerve fiber and all of the muscle fibers that it innervates

34

Second Step of Muscle Fiber Contraction

Acetylcholine (ACh) is released from the neurons and bind to the muscle fibers. (Synaptic vesicles of the neuron contain ACh, a neurotransmitter, where it binds with receptor on the sarcolemma)

35

Third Step of Muscle Fiber Contraction

Binding of ACh stimulates impulses down the T-tibules causing calcium to be released from the sarcoplasmic reticulum

36

Fourth Step of Muscle Fiber Contraction

Calcium complex (troponin) modifies tropomyosin, exposing binding site

37

Fifth Step of Muscle Fiber Contraction

Myosin head binds with actin (thanks to ADP + P)

38

Sixth Step of Muscle Fiber Contraction

ADP + P are released, resulting in a power stroke

39

Seventh Step of Muscle Fiber Contraction

Additional ATP allows for myosin head to return to resting position and calcium to be pumped back into sarcoplasmic reticulum

40

Electromyogram (EMG)

Method of detecting changes in ions associated with muscle contraction

41

Electrical voltages

Difference in charge from place to place - can be detected on surface of skin

42

Motor unit

A nerve fiber and all of the muscle fibers it stimulates - "all or none"

43

Motor Unit Recruitment

Increases the strength of contraction by increasing the number of motor units in use

44

Fatigue sets in when...

...you have recruited same motor units for a while and depleted energy (ATP)

45

Muscle twitch is...

A single motor unit contraction, caused by infrequent electrical impulses, and lasts a fraction of a second.

46

Summation

Increase in muscle contraction until maximum sustained contraction (tetanus) is reached, and lasts until fatigue (muscle relaxes despite stimulation due to depletion of energy reserves).

47

Tetanus

Maximal sustained contraction

48

Fatigue

Decrease in a muscle's ability to generate force, when the muscle relaxes despite stimulation due to depletion of energy reserves.

49

Four sources of ATP for muscle contraction...

Stored in muscle fibers
Creatine-phosphate pathway
Fermentation
Cellular Respiration

50

Creatine-phosphate pathway

Fastest way to acquire ATP but only sustains cell for seconds; builds up when a muscle is resting (anaerobic).

51

Fermentation

Fast-acting but results in lactate build-up (anaerobic)

52

Cellular Respiration

Not an immediate source of ATP, but best long term source (aerobic)

53

Myoglobin

Protein that transports oxygen directly to mitochondria of muscle cells

54

Fast Twitch Fiber Characteristics

Creatine-Phosphate pathway and fermentation for ATP
Fewer Mitochondria
Light Color
Fewer blood vessels
Little myoglobin

55

Slow Twitch Fiber Characteristics

Cellular Respiration for ATP
More mitochondria
Dark color
More blood vessels
More myoglobin

56

Fast Twitch Muscle Characteristics

Anaerobic
Explosive Power
Fatigues Easily

57

Slow Twitch Muscle Characteristics

Is Aerobic
Steady Power
Has Endurance

58

Spasms

Sudden, involuntary muscle contractions that are usually painful

59

Seizure/Convulsion

Multiple spasms of skeletal muscles

60

Cramps

Strong, painful spasms often of the leg and foot

61

Strain

Stretching or tearing of a muscle

62

Sprain

Twisting of a joint involving muscle, ligaments, and joints

63

Fibromyalgia

Chronic achy muscles; not well understood

64

Muscular Dystrophy

Group of genetic disorders in which muscles progressively degenerate and weaken

65

Myasthenia Gravis

Autoimmune disorder that attacks ACh receptors and weakens muscles of the face, neck, and extremities

66

Muscle Cancer

Cancers originating in support tissues (bone, muscle) are called sarcoma

67

Amyotrophic Lateral Sclerosis (ALS)

Lou Gehrig's Disease; genetic disorder in which motor neurons degenerate leading to loss of voluntary muscle contractions

68

Muscles contribute to homeostasis how...?

Allow for movement to let us respond to stimuli, digest food, breathe, etc.
Protect body parts
Helps to regulate body temperature