Skeletal Muscular System

Question 1

5 Functions of Skeletal Muscles

Answer 1

1 produce skeletal mvmt

2 maintain posture + body position

3 support soft tissue + visceral organs

4 regulate entry + exit of material thru orifices

5 maintain body temp thru contraction and use of energy

Question 2

Tissues of Skeletal Muscle

Answer 2

EPIMYSIUM dense irregular connective tissue (seperates muscle fr surrounding tissues/organs + connected to deep fascia)

PERIMYSIUM connective tissue fibers w collagen, elastic fibers, + numerous blood vessels +nerve supply (divides muscle into internal compartments w fascicles)

ENDOMYSIUM reticular fibers w myosatellite cells scatered bw endomysium + muscle fibers[surrounds each skeletal fiber (cell) + supportsthe capillaries for each fiber]

Question 3

Fascicle

Answer 3

Bundles of muscle cells surrounded by a Perymysium membrane and Endomytrium plasma

Question 4

APONEUROSES

Answer 4

tendons that form thick, flattened sheets

Question 5

at the end of the muscle, collargen fibers of epimysium, perimysium, and endomysium come together to form a _______.

Answer 5

TENDON

collagen fibers of tendons are continuous w periosteum and matrix of bone to which it attaches + makes extremely strong bond

Question 6

Nerves + Blood Vessels of Skeletal Muscles

Answer 6

enters epimysium, branches out through perimysium + attached to individual muscle fibers in endomysium

provides control over contraction

Question 7

NEUROMUSCULAR JUNCTION

NMJ

Answer 7

site where chem communicatin bw a neuron and skeletal muscle fiber occurs

NMJ is made up of axon terminal of neuron, regiin of plasma membrane called Motor End Plate, narrow space bw called synaptic cleft, and membrane of muscle fiber

Question 8

SARCOLEMMA

Answer 8

plasma membrane of skeletal muscle

Question 9

SARCOPLASM

Answer 9

cytoplasm w/in sarcolemma

Question 10

Unique Qualities of SKELETAL MUSCLE FIBERS

Answer 10

• larger than other cells (100 um and 30 cm-16in)
• multinucleate (can contain hundreds in the sarcolemma)
• Transverse Tubules (T Tubules) that extend on sarcoplasm and conduct electrical impulses to stimulate contractions

Question 11

3 Types of Muscles

Answer 11

Skeletal muscle - only type of muscle w voluntary control
Smooth muscle
Cardiac muscle

Question 12

Attachment sites of Skeletal Muscles

Answer 12

skins, eyes, bone

Question 13

Types of Muscle Contractions

Answer 13

1  Reflexive 
2 Tonic
3 Phasic
3a  Isometric
3b  Isotonic

Question 14

Reflexive Contractions

Answer 14

controlled by Autonomic Nervous System but can be temporarily override consciously

ex) diaphragm is controlled bt ANS but if you think about ur breathing, you can control the contraction.

Question 15

Tonic Constraction

Answer 15

Remain in a state of contraction for long periods of time. Mostly for posture and stability maintenance

ex) muscles of lower back hold us up and are resistant to fatigue

Question 16

Phasic - Isometric Contraction

Answer 16

generates force while maintaining a constant length

ex) holding up a heavy box w arms - constant generating of contraction to keep it stabilized and up

Question 17

Phasic - Isotonic Contraction

Answer 17

Concentric - muscle overcomes opposing force and shortens

Eccentric - force of a muscle is less than weight and lengthening occurs

Question 18

9 Types of Movements

Answer 18

Flexion
Extension
Rotation
Elevation
Depression
Pronation
Supination
Abduction
Adduction

Question 19

Flexion

Answer 19

action that decreases the angle bw 2 bones

ex) flexing the elbow shortens the angle bw humerus and forearms

Question 20

Extension

Answer 20

increases the angle bw 2 bones

ex)

Question 21

Rotation

Answer 21

spinning mvmt around axis

ex) turning head around axis of vertebral column

Question 22

Elevation

Answer 22

upwards mvmt on vertical plane

ex) mvmt of mandible up to bite

Question 23

Depression

Answer 23

mvmt of structure downwards

Question 24

Pronation

Answer 24

rotational mvmt of joints (usually on hand or forearm so that palm faces posteriorly)

Question 25

Supination

Answer 25

returns pronated hand to anatomical position

Question 26

Abduction

Answer 26

moving a structure away fr midline

ex) raising arm away fr sides

Question 27

Adduction

Answer 27

moving a structure towards the midline