Chapter 7- Muscular system

Question 1

What is the primary and secondary functions of the muscular system

Answer 1

primary: move skeleton
secondary: heat production

Question 2

What are the two types of muscle tissue?

Answer 2

smooth muscle

cardiac muscle

Question 3

skeletal muscle tissue is made up of what kind of muscle cells?

Answer 3

myocytes

muscle fibers

Question 4

how are muscles anchored to bones?

Answer 4

tendons, which can be rope like or flat (aponeurosis)

Question 5

describe how tendons bind to bones

Answer 5

its made up of fibrous tissues and merges with the fascia that covers the muscles and with the perisoterum (fibrous connective tissue) that covers the bone.

Question 6

on average how many tendons per muscle, and what are they called?

Answer 6

2, each attaching to different bones.

the immobile attachment to the muscle is called origin, the more movable attachment is called insertion.

Question 7

what are the two general types of muscle arrangements?

Answer 7

opposing > antagonist or antagonistic muscle

cooperative > synergists or synergistic muscle

Question 8

define how muscles work in an antagonistic arrangement and how the tendons are involved in the movement (use the arm as an example)

Answer 8

tendons origin located on scapular the insertion tendon is located on the radius/ulna (forearm bone).
The biceps contract and flexes the forearm, when they relax the tricep contracts and pulls(extends) the forearm to straighten the elbow.

Question 9

what is the purpose of Range-Of-Motion exercises?

Answer 9

designed to stretch and contract the antagonist muscles of a joint to preserve as much muscle function and joint mobility as possible.

Question 10

What are synergistic muscles?

Answer 10

muscles that have the same function/work together to perform a particular function.
- can also refer to muscles that help stabilize or steady a joint to make more precise movements.

Question 11

Give an example of a synergistic muscle using the bicep example.

Answer 11

muscle is called brachialis muscle.
palm up = bicep does work
thumb up- shared work
palm down- brahialis does the work

Question 12

what is a “primary mover” in terms of muscle movement?

Answer 12

primary movement using basic anatogistic muscles. Think natural movement using biggest and strongest muscles for that movement.

Question 13

How does the brain coordinate movement?

Answer 13

nerve impulse originates from frontal lobe of cerebrum. motor areas generate electrochemical impulses that travel through muscle neurons to muscle fibres, causing them to contract.

Question 14

whats a motor unit?

Answer 14

when a single axon of a motor neuron may branch extensively, and therefore innervates +++ muscle fibres.

Question 15

what is muscle coordination and what part of the brain regulates this action?

Answer 15

the action of many muscles working together contracting and relaxing to make smooth and efficient movements. ie: walking, and dancing.
its regulated by the cerebellum

Question 16

what is muscle tone?

Answer 16

the theory that all muscles are in a slight state of contraction except when asleep

Question 17

what improves coordination?

Answer 17

good muscle tone through exercise.

Question 18

Generally what are the two types of exercises genres you can perform?

Answer 18

isotonic exercise: muscle contracts and bring about movement. will produce tone, and strength via aeorbic work.
isometric exercise: contraction without movement > will produce tone and strength by not aeorbic

Question 19

what is aerobic exercise?

Answer 19

isotonic exercise performed for 30 mins or more, and it strengthens the heart and respiratory muscles as well as muscles attached to the skeleton.

Question 20

what are the two types of isotonic contractions?

Answer 20

1. concentric contractions: shortening of the muscle as it exerts force
2. eccentric contractions: lengthening of a muscle as it still exerts force.

Question 21

Give examples of isotonic and isometric exercises.

Answer 21

picking up a pencil: isotonic
holding the pencil: isometric
pulling a door open= isotonic
holding door open= isometric

Question 22

What is the striated muscle?

Answer 22

newly discovered, and is an endocrine tissue, that excretes Irisin during exercise. This hormone affects adipose tissue and converts white adipocytes to brown adipocytes.

Question 23

What is muscle sense (proprioception)?

Answer 23

the brains ability to known where our muscles are and what they are doing without our having to look at them and be aware of them.

Question 24

within muscle cells are stretch receptors. what do they do?

Answer 24

detect changes in the length of a muscle as it stretched, they generate an impulse to the brain to let it know where the muscle is.

Question 25

What are anabolic steroids?

Answer 25

synthetic drugs similar in structure and action to the male hormone testosterone.

Question 26

What provides energy for muscles to contract?

Answer 26

#1 ATP > not stored in abundance 
#2 creatine phosphate > used to synthesize more ATP
#3 glycogen > most abundant energy source, breaks into glucose then into ATP, heat is a byproduct.

Question 27

what is myoglobin

Answer 27

protein in muscle cells that store some oxygen within the cell. They also contain iron- give muscle its dark colour.
* quickly used up during strenuous exercise.

Question 28

what is oxygen debt?

Answer 28

when the muscle fibres run out of stored up oxygen. When this happens the cell respiratory process becomes anaerobic and glucose is converted to lactic acid which contributes to muscle fatigue and pain (cramps)

Question 29

Describe a muscle fibre

Answer 29

has its own motor nerve ending called neuromuscular junction
axon terminal is the enlarged tip of the motor neuron and it contains the sac of the neurotransmitter acetylcholine.
membrane of muscle fibre is sarcolemma, contains the receptor sites for acetylcholine and an inactivator called cholinesterase. The synapse is the small space between axon terminal and sarcolemma.
in the fibre theres contracting unites called sarcomeres, arranged in cylinders call myofibrils.
surrounding sarcomeres are sarcoplasmic reticules (Ca+ reserve)

Question 30

What are the proteins involved in muscle fibre movements?

Answer 30

myosin, actin (contractual fibres)
titin (anchor protein)
troposin and tropomyosin (inhibitor proteins)

Question 31

Describe the axon terminal of the neuromuscular junction

Answer 31

end of a motor neuron; contains vesicles of acetylcholine and are opened by arrive of nerve impulse

Question 32

Describe the sarcolemma of the neuromuscular junction

Answer 32

cell membrane of the muscle fibre

It has receptors for acetylcholine

Question 33

Describe the synaptic cleft of the neuromuscular junction

Answer 33

space between the axon terminal and the sarcolemma

Question 34

Describe the acetylcholine receptors of the neuromuscular junction

Answer 34

origins of the sarcolemma that are channels for Na+ ions, are opened by Acetylcholine

Question 35

Describe the acetylcholine (Ach) of the neuromuscular junction

Answer 35

neurotransmitter released by the axon terminal; diffuses across the synaptic cleft bonds to the ACh receptors and brings about depolarization of the sarcolemma with an influx of Na+ ions

Question 36

Describe cholinesterase-receptors of the neuromuscular junction

Answer 36

the enzyme that inactivates acetylcholine; prevents continued depolarization and contraction.

Question 37

Describe the polarization of a muscle fibre

Answer 37

relaxed muscle = polarized sarcolemma.
polarization = Na+ outside cell and K+ inside the cell. [] maintained from sodium and potassium pumps.
depolarization caused by ^ of acetylcholine from neuron impulse. ACh receptors make cells permutable to Na+ ions. Ions rush into the cell and the fibre becomes depolarized, the electric pulse generates active potential then passes along muscle fibre, via T tubles.
repolarization completes the action potential and K+ ions are outflown from cell.

Question 38

what is the term given to nerve impulses that arrive in a continuous stream and produce a sustained contraction?

Answer 38

tetanus

- muscle fibres remain contracted and are capable of effective movements.

Question 39

when nerves don’t receive impulses they become paralyzed. What happens to the paralyzed muscles?

Answer 39

they eventually become atrophic (become small d/t lack of use)

Question 40

what happens to muscles as they age?

Answer 40

die and are replaced with fibrous tissue and fat.

loss of muscle fibres contributes to loss of propricepton which leads to unsteadiness

Question 41

what helps prevent atrophy of muscles?

Answer 41

exercise, by maintaining muscle function.

Question 42

what is neurotoxin

Answer 42

a chemical that disrupts the normal functioning of the nervous system.

Question 43

what is Tetanus? (disease)

Answer 43

the inability of muscles to relax. the toxin is produced by the tetanus bacteria and affects nervous system in a way that muscles fibres get to many signals and spasms.

Question 44

what is Botulism?

Answer 44

type of food poisoning - without typical characteristics,

froma bacteria and inhibits the release of ACh. Muscles become paralyzed.

Question 45

what is muscle dystrophy?

Answer 45

a group of genetic disease in which muscle tissue is replaced by fibrous connective tissue or by fat.
- neither tissue can contract and therefore muscle function is loss.

Question 46

Whats the most common form of muscle dystrophy?

Answer 46

Duchenne’s muscular dystrophy
skeletal muscle and cardiac muscles are affected.
Age 2-5, Sex linked X train. this affects the production of protein Dystrophin - needed for stability of sarcolemma and ion movement.

Question 47

What is Myasthenia gravis?

Answer 47

autoimmune disorder characterized by extreme muscle fatigue.
autoantibodies destroy the acetylcholine receptors on the sarcolemma.

Question 48

What is the action Flexion

Answer 48

decrease the angle of a joint

Question 49

What is the action extension

Answer 49

increase the angle of a joint

Question 50

What is the action adduction

Answer 50

move closer to the midline

Question 51

What is the action abduction

Answer 51

to move away from the midline

Question 52

What is the action pronation

Answer 52

to turn the palm down

Question 53

What is the action suprination

Answer 53

to turn the palm up

Question 54

What is the action dorsiflexion

Answer 54

to elevate the foot

Question 55

What is the action plantar flexion

Answer 55

to lower the foot

Question 56

What is the action inversion

Answer 56

to move the sole of the foot medially at the ankle

Question 57

What is the action eversion

Answer 57

to move the sole of the foot laterally at the ankle

Question 58

What is the action rotation

Answer 58

to move a bone around its longitudinal axis

Question 59

intramuscular injections are used when repod absorption is needed. Where and why is this done?

Answer 59

muscle has a good blood suply, safest spot is considered the gluteus medius muscle. Alternative sites: vastus lateralis (thigh), deltoid muscle (shoulder)