Week 3 Lecture

Question 1

what are the 4 basic properties of muscle?

Answer 1

1. Excitability
2. Contractility
3. Extensibility
4. Elasticity

Question 2

what are the 3 main muscle types?

Answer 2

skeletal muscle
cardiac muscle
smooth muscle

Question 3

what are the characteristics of cardiac muscle?

Answer 3

• striated involuntary
• short cells w one central nucleus
• incapable of contracting

Question 4

what are the characteristics of smooth muscle?

Answer 4

• non striated involuntary
• short cells w one nucleus
• can divide and regenerate

Question 5

what are the characteristics of skeletal muscle?

Answer 5

• striated voluntary muscle
• long cells that are multinucleate
• incapable of cell reproduction

Question 6

what are 5 main functions of skeletal muscles?

Answer 6

produce skeletal movement
maintain posture and body position
support soft tissue
regulate entering and exiting of material
maintain body temp

Question 7

what are the three layers of connective muscle tissue?

Answer 7

Epimysium
perimysium
endomysium

Question 8

what is a myofibril?

Answer 8

a highly organized bundle of contractile protein

Question 9

what is the sarcomere?

Answer 9

smallest functional unit of skeletal muscle

Question 10

what is the difference between actin and myosin?

Answer 10

actin - thin protein filament
myosin - thick protein filament

Question 11

M-line

Answer 11

centre of A-band where myosin filaments are held together

Question 12

Z-disc

Answer 12

centre of I-band where actin filaments are held together

Question 13

I-band

Answer 13

made of only actin filaments (light region)

Question 14

A-band

Answer 14

myosin filaments with overlapping actin filaments at edges (dark region)

Question 15

H-zone

Answer 15

made of only myosin filaments, centre of A-band

Question 16

name every region of the sarcomere

Answer 16

I-band
a-band
m-line
h-zone
z-line

Question 17

Skeletal muscles consist of…

Answer 17

Muscle Fascicles

Question 18

muscle Fascicles consist of…

Answer 18

muscle fibers

Question 19

muscle fibers consist of…

Answer 19

myofibrils

Question 20

myofibrils consist of…

Answer 20

sarcomeres

Question 21

sarcomeres consist of…

Answer 21

myofilaments

Question 22

myofilaments are made of…

Answer 22

actin and myosin!

Question 23

what are the 2 steps of muscle fiber contraction

Answer 23

1. Excitation phase
2. contraction phase

Question 24

what happens during the excitation phase? (5 steps)

Answer 24

1. an impulse travels down the axon of a nerve
2. ach is released from the end of the axon into the neuromuscular synapse
3. results in an action potential, and causes the s.r. to release its stored calcium ions
4. calcium binds to troponin (uncovering the binding sites of actin)
5. begins the contraction of the muscle

Question 25

what happens during the contraction phase?

Answer 25

1. contraction cycle begins
2. active-site exposure
3. cross-bridge formation
4. myosin head pivoting (power stroke)
5. cross bridge detachtment
6. myosin reactivation

Question 26

what is the triad on a muscle fiber made up of?

Answer 26

the sarcoplasmic reticulum and the T-tubules

Question 27

ex. of a parallel muscle

Answer 27

biceps brachii

Question 28

ex of parallel muscle w bands

Answer 28

rectus abdominus

Question 29

wrapping muscle

Answer 29

supinator

Question 30

convergent muscle

Answer 30

pectoralis

Question 31

unipennate muscle

Answer 31

extensor digitorum

Question 32

bipennate muscle

Answer 32

rectus femoris

Question 33

multipennate muscle

Answer 33

deltoid

Question 34

circular muscle (lips)

Answer 34

orbicularis oris

Question 35

what are the factors influencing the motion and power of muscles?

Answer 35

of muscle fibers

shape:
number:
size: (of muscle fibers)
orientation relative to tendon

Question 36

first class lever

Answer 36

neck (resistance, fulcrum, AF)

Question 37

Second class lever

Answer 37

plantar flexion (fulcrum, resistance, AF)

Question 38

third class lever

Answer 38

elbow flexion (fulcrum, AF, resistance)

Question 39

ex of a pulley in the body

Answer 39

lateral malleolus or patella
changing direction of force