Muscles

Question 1

The 4 unique characteristics of muscle tissue

Answer 1

Excitability: respond to input from stimuli

Contractility: muscle fibres can contract and shorten

Elasticity: when tension is removed muscle cells return to their original length

Extensibility: muscle fibres can be stretched beyond their resting length

Question 2

Why are muscles considered organs

Answer 2

they contain all 4 tissue types

Question 3

Characteristics of Skeletal Muscle Tissue

Answer 3

striated
usually attached to bone (bar most facial muscles)
multi-nulcei
voluntary control

Question 4

functions of skeletal muscle tissue

Answer 4

for body movement
maitain posture
regulate temperature
storage and movement of materials
support

Question 5

composition of muscles

Answer 5

muscle fibres (muscle cells)
blood vessels
nerves

Question 6

organisation of muscles

Answer 6

muscle
fascicle
muscle fibre (muscle cells)
myofibrils
myofilaments (actin and myosin)

Question 7

how many layers of CT do muscles have

Answer 7

3 layers composed of collagen and elastic fibres

Question 8

what is the purpose of the CT in muscles

Answer 8

provides protection
site for blood vessels and nerve distribution
means for attachment to the skeleton

Question 9

What are the 3 CT layers

Answer 9

Endomysium
Perimysium
Epimysium

Question 10

The location and tissue type of each CT layer

Answer 10

Endomysium - surrounds and electrically insulates each muscle fibre, Areolar CT
Perimysium - surrounds the fascicles, dense irregular CT
Epimysium - surrounds the entire muscle, dense irregular CT

Question 11

what are the names for muscle-specific plasma membrane, cytoplasm and smooth ER

Answer 11

sarcolemma
sarcoplasm
sarcoplasmic reticulum (regulates Ca2+)

Question 12

name the thick and thin filaments

Answer 12

thick - Myosin
thin - Actin

Question 13

what is sliding filament theory

Answer 13

the mechanism for contraction where the myosin heads ‘walk’ along the binding sites of the Actin

Question 14

cardiac muscle fibre features

Answer 14

striated
y-shaped
one/two nuclei
joined by intercalated discs (gap junctions for communication)
autorhythmic
under involuntary control

Question 15

Smooth muscle fibre features

Answer 15

short fusiform cells (tear drop)
single central nucleus
no striations
thin filaments attached to Dense Bodies
under involuntary control

Question 16

name of the convergence of CT of muscles

Answer 16

Tendons

Question 17

What do Tendons join

Answer 17

Muscle to bone

Question 18

What do Ligaments join

Answer 18

Bone to bone

Question 19

name of the less moveable point of attachment of a muscle

Answer 19

origin (proximal end)

Question 20

name the more moveable point of attachment of a muscle

Answer 20

insertion (distal end)

Question 21

what is muscle tone

Answer 21

the constant tension in resting muscles, when motor units are randomly stimulated to avoid fatigue

Question 22

what is isometric contraction

Answer 22

when the length stays constant while tension is changing

Question 23

what is isotonic contraction

Answer 23

when the tension is constant, while length is changing

Question 24

what are the two stages of isotonic contaction

Answer 24

concentric contraction
eccentric contraction

Question 25

what is concentric contraction

Answer 25

when a muscle under tension shortens

Question 26

what is eccentric contraction

Answer 26

when a muscle under tension lenghtens

Question 27

what is the term for circular muscle fibre pattern

Answer 27

Orbicularis (ie. orbicular oris or orbicular oculi)

Question 28

what is the term for parallel muscle fibre pattern

Answer 28

Rectus (ie. Rectus abdominis)

Question 29

what is a convergent muscle pattern

Answer 29

when a muscle is widespread over a large area, and the fascicles come to a single common point. ie. pectoralis major

Question 30

what is a pennate muscle pattern

Answer 30

when muscle fibres attach obliquely (on an angle) to the tendon (for a greater force production)

Question 31

what is a unipennate muscle pattern

Answer 31

a type of pennate muscle where all the fibres attach to a single side of the tendon ie. extensor digitorum

Question 32

what is a bipennate muscle pattern

Answer 32

a type of pennate muscle where the fibres attach to two side of the tendon ie. Rectus femoris

Question 33

what is a multipennate muscle pattern

Answer 33

a type of pennate muscle where multiple rows of muscle fibres attach to a tendon whose central tendon has branched into multiple tendons. ie. Deltoid

Question 34

what is the Agonist

Answer 34

it is the focus. It produces a specific movment the Prime Mover ie. triceps brachii is the agonist of antibrachium extension

Question 35

what is the antagoinst

Answer 35

a muscle whose action apposes the agonist ie. the biceps brachii is an antagonist to the triceps brachii

Question 36

what is the synergist

Answer 36

a muscle whose action supports the agonist to perform its action