Chapter 6 Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

muscle movement

A

voluntary - conscious control over movements.

involuntary - generally beyond our conscious control.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 types of movement

A
  1. excitable - contract in response to chemical and/or electrical signals from other organ systems
  2. contract (shorten) - all muscles have only one basic mechanism of action
  3. relax - returning to their orginal length.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

3 types of muscles

A
  1. skeletal - attach to skeleton and give us strength and mobility
  2. cardiac - pump blood throughout the body
  3. smooth muscle - walls of uterus propel the child through the birth canal.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

skeletal muscle

A

interact with the skeleton and cause bones to move (or prevent them from moving) relative to each other.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

synergistic muscles

A

work together to create the same movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

antagonistic muscles

A

muscles that oppose each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

origin

A

joins to a bone that remains relatively stationary.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

insertion

A

other end of the muscles, attaches to another bone across a joint.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

muscle

A

group of individual muscle cells, all with the same origin and insertion and all with the same function.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

fascicles

A

a muscle appears to be arranged in bundles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

fascia

A

enclosed in a sheath of a type of fibrous connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

muscle fibers

A

fascicle contains anywhere from a few dozen to thousands of individual muscle cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

myofibrils

A

nuclei are located just under the cell membrane because nearly the entire interior of the cell is packed with long cylindrical structures arranged in parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

sarcomere

A

segment of a myofibril from one Z-line to the next. consists of myosin and actin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

myosin

A

thick filaments composed of a protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

actin

A

interspersed at regular intervals within filaments of a different protein

17
Q

4 keys makes a skeletal muscle cell contract and relax

A
  1. a skeletal muscle cell must be activated by a nerve. It does not contract on its own.
  2. Nerve activation increases the concentration of calcium in the vicinity of the contractile proteins.
  3. The presence of calcium permits contraction. the absence of calcium prevents contraction
  4. When muscle cell is no longer stimulated by a nerve, contraction ends
18
Q

Motor neurons

A

skeletal muscle cells are stimulated to contract by certain nerve cells. releases acetylcholine at the neuromuscular junction

19
Q

neurotransmitter

A

chemical released by nerve cells that has either an excitatory or inhibitory effect on another excitable cell

20
Q

neuromuscular junction

A

junction between a motor neurons and skeletal muscle cells

21
Q

sarcoplasmic reticulum

A

T tubules are in close contact with a series of membrane-bound chambers. store ionic calcium

22
Q

sliding filament mechanism

A

muscles contract when sarcomeres shorten and sarcomeres shorten when the thick and thin filaments slide past each other

23
Q

calcium

A

release of calcium from the sarcoplasmic reticulum triggers contraction. Calcium allows cross-bridges to form between myosin and actin, which leads to contraction by a sliding filament mechanism.

24
Q

ATP

A

Energy from the breakdown of ATP is required for contraction and for calcium transport. ATP is produced from metabolism of creatine phosphate and glycogen stores within the muscle, and from glucose and fatty acids obtained from the blood.

25
Q

2 types of contraction

A
  1. Isotonic - occur whenever a muscle shortens while maintaining a constant force.
  2. isometric - force is generated, muscle tension increases and muscle may even shorten a little as tendons are stretched slightly but bones and objects do not move
26
Q

Motor unit

A

smallest functional unit of muscle contraction because when the motor neuroncles is activated all the muscle cells in that motor unit are activated together.

27
Q

muscle tension

A

mechanical force that muscles generate when they contract

28
Q

3 factors of tension

A
  1. number of muscle cells in each motor unit
  2. number of motor units active at any one time
  3. frequency of stimulation of individual motor units
29
Q

all-or-none principle

A

muscle cells are completely under the control of their motor neuron.

30
Q

recruitment

A

increasing tone or force by activating more motor units

31
Q

stimulus-twitch has 3 stages

A
  1. Latent period - time between stimulation and the start of contraction
  2. contraction - time during which the muscle actually shortens
  3. relaxation - muscle returns to its original length
32
Q

summation

A

increasing muscle force by increasing the rate of stimulation of motor units

33
Q

slow-twitch fibers

A

rely on aerobic metabolism and are most useful for endurance

34
Q

fast-twitch

A

capable of short bursts of high-internsity work and are most useful where strength is required.

35
Q

cardiac and smooth muscle

A

involuntary and can contract without signals from the nerves. but they are also capable of responding to nerves

36
Q

cardiac

A

contracts and relaxes rhythmically. has thick and thin filaments arranged in sarcomeres. found only in heart, pumping blood, spontaneous (pacemaker cells) modifiable by nerves.

37
Q

smooth

A

sustain a contraction indefinitely. fillaments in smooth are arranged in bundles that crisscross the cell. found in walls of blood vessels and walls of organs of the digestive respiratory urinary and reproductive tracts; control of blood vessel diameter

38
Q

Muscular dystrophy

A

abnormal growth, a single defective gene results in the lack of a particular muscle cell protein.