Muscle Systems Flashcards Preview

Bio 2320 > Muscle Systems > Flashcards

Flashcards in Muscle Systems Deck (33):
1

Skeletal muscles are ....?

multinucleate, striated, and covered by endomysium

2

Muscle fascicles are ...?

bundles of muscle fibers which are covered by perimysium

3

The muscle trunk is ...?

a bundle of fascicles and is covered by epimysium and fascia

4

The connective tissue of muscles is ...?

bound firmly to the connective tissue of the tendon.
-which connects to the periosteum and the bone matrix

5

A muscle fiber is ...?

a single cell consisting of sarcolemma, sarcoplasm, several nuclei, and myofibrils

6

Myofibrils are ...?

bundles of thick and thin filaments which are covered by sarcoplasmic reticulum

7

What are organized into sarcomeres?

Thick and thin filaments

8

Thin filaments are composed of ...?

actin, tropomyosin, and troponin

9

Thick filaments are composed of ...?

myosin

10

Events of a Muscle Contraction
1st Action

The action potential in the motor neuron reaches the axon termini, which release acetylcholine [ACh].

11

Events of a Muscle Contraction
2nd Action

ACh diffuses across the cleft of the neuromuscular junction, inducing an action potential, which spreads over the sarcolemma and down the T tubules.

12

Events of a Muscle Contraction
3rd Action

The action potential reaches the sarcoplasmic reticulum, causing the SR to release Ca++.

13

Events of a Muscle Contraction
4th Action

Ca++ binds to troponin, troponin-tropomyosin moves, exposing myosin-binding sites on actin.

14

Events of a Muscle Contraction
5th Action

Myosin head attaches to actin [=crossbridge formation]; myosin head changes shape, thick and thin filaments slide past each other.

15

Events of a Muscle Contraction
6th Action

Z-discs are drawn toward each other; sarcomeres shorten; muscle fiber shortens; muscle shortens.

16

Events of a Muscle Contraction
7th Action

Myosin head binds fresh ATP and releases from actin.

17

Events of a Muscle Contraction
8`th Action

As long as ATP and Ca++ are present, the cycle continues.

18

The less moveable part of the muscle

origin

19

The more moveable part of the muslce

insertion

20

What do synergists do?

function together to produce movement

21

What do antagonists do?

oppose or reverse the action of another muscle

22

What do prime movers do?

responsible for movement

23

Head moving muscles cause ...?

flexion, extension, rotation, abduction, and adduction of the head

24

Facial muscles originate on...
insert on...
and cause movement of the...

skull bones or fascia
skin
facial skin, lips, and eyelids

25

What opens the jaw
What closes the jaw

gravity
3 muscles

26

Most respiratory movement is caused by ?

the diaphragm

27

Other than the diaphragm, what muscles aid in respiration?

muscles attached to the ribs

28

Abdominal wall muscles do what?

hold and protect abdominal organs and cause abduction, rotation, and flexion of the vertebral column.

29

Muscles which attach the humerus to the scapula or the trunk cause ...?

flexion, extension, abduction, adduction, rotation, or circumduction of the arm.

30

Anterior pelvic muscles cause ...?

flexion of the thigh.

31

Muscles of the buttocks ...?

extend, abduct, and rotate the thigh.

32

The thigh can be divided into 3 compartments:
medial, anterior, posterior
What do they do?

medial compartment muscles adduct the thigh
anterior compartment muscles flex the thigh
posterior compartment muscles extend the thigh.

33

The leg muscles can be divided into 3 compartments
medial, anterior, posterior
What do they do?

anterior compartment muscles dorsiflex, invert, or evert the foot
lateral compartment muscles plantar flex and evert the foot
posterior compartment flex the leg, plantar flex and evert the foot, and flex the toes.