Muscles

Question 1

what are the 3 main types of muscles

Answer 1

skeletal
cardiac
smooth

Question 2

is skeletal involuntary or voluntary

Answer 2

voluntary

Question 3

is cardiac involuntary or voluntary

Answer 3

involuntary

Question 4

is smooth involuntary or voluntary

Answer 4

voluntary

Question 5

explain type 1fibre

Answer 5

type 1 fibre is slow twitch
it contracts slower and becomes less fatigue slower
high capacity for aerobic respiration

Question 6

explain type 11a fibres

Answer 6

these fibres are fast-oxidative
fast contracting
less reliant on oxygen

Question 7

explain type 11x fibres

Answer 7

these fibres fast-glycolytic
used for anaerobic activities
depend on anaerobic respiration

Question 8

explain anatomy of skeletal structure

Answer 8

the skeletal muscles contain 1000s of individual muscle fibres combined into bundles known as fascicle. each fascicle is held together with connective tissues known as perimysium. each fascicle contains 10-100 muscle fibres. it depends on each muscle. all fascicle are kept in place by a muscle sheath known as epimysium. this protects muscles from friction with other muscles and bones. each individual fibre is surrounded by a connective tissue which acts as an insulator. this is known as endomysium

Question 9

explain sensory neuron

Answer 9

carries information from the skin to the central nervous system

Question 10

explain motor neuron

Answer 10

carries information from the cns to the muscles

Question 11

explain the neuromuscular process of muscle contraction

Answer 11

Muscle contraction occurs when the cns sends a nerve impulse to the muscle
a motor neurone receives this signal, which is contained in a muscle fibre. it then converts the signal into a muscle contraction. where this all occurs is known as the synapses
when the impulse is received, motor neurone releases acetylocholine. this transmits the signal into a muscle fibre resulting in a contraction.
the release of acetylochloine occurs at neurotransmitter

Question 12

What is sliding filament theory?

Answer 12

Sliding filament theory explains how muscles contract.
-Muscles made of thin muscle fibres- myofibrils-containing myosin and actin filaments in series
-During contraction myosin filaments attach to
actin filaments- form chemical bonds called crossbridges
-This basic unit is a sarcomere
-Myosin molecules act like a ratchet, while actin molecules form passive filaments transmitting the force generated by the myosin to the ends of the muscle tissue- myosin progresses along an actin filament, constantly binding, ratcheting and then letting go- this allows muscles to contract
-When the muscle does not need to contract, thin strands of a further protein (tropomyosin) are wrapped around the
actin filaments to stop the myosin from binding
-As a muscle undergoes contraction:
▸molecules called troponin attach to tropomyosin
▸calcium ions are introduced into the muscle cell and bind with troponin
▸calcium binding changes the shape of troponin, causing tropomyosin to move, exposing actin
▸myosin is now free to bind with actin and the muscle contracts

Question 13

What are muscles made of?

Answer 13

Thin muscle fibres known as microfibrils each containing myosin and actin filaments in series (one after the other).

Question 14

What happens to myosin filaments during contraction?

Answer 14

During contraction myosin filaments attach to actin filaments forming chemical bonds called crossbridges. This basic unit of a muscle cell is known as a sarcomere.

Question 15

What do sarcomeres do?

Answer 15

Give skeletal muscle tissue its striped or striated appearance.

Question 16

What are the different areas that sarcomeres divided into?

Answer 16

-H zone- the centre of the A band of each sarcomere. Here there are only thick filaments, no thin filaments.
-Z line- The area at each end of separate sarcomeres where the actin filaments are attached.
-A band- the active area where contraction takes place between the actin filaments and the myosin filaments. It is the relatively dark area of the sarcomere and contains the thick filaments.
-I band- the region between adjacent A bands, in which there are only thin filaments and no thick filaments. Each I band extends across two adjacent sarcomeres.

Question 17

Name the 3 types of contractions

Answer 17

Concentric
Eccentric
Isometric

Question 18

Explain concentric

Answer 18

Make any movements. Muscle will shorten as muscle fibre contracts. In bicep curl bicep shorten

Question 19

what are the 3 muscle fibres

Answer 19

type 11a
type 11x
type 1

Question 20

What are Troponin and tropomyosin?

Answer 20

-Proteins that form part of the thin or actin filament
-Tropomyosin is a rod-shaped protein that spirals about the actin core to stiffen it- Troponin binds to the tropomyosin and helps it bind to the actin

Question 21

What does Sarcoplasmic reticulum do?

Answer 21

Regulates the calcium ion concentration in the muscle cells

Question 22

agonist

Answer 22

The muscle that shortens to move a joint.This is the muscle principally
responsible for the movement taking place

Question 23

antagonist

Answer 23

The muscle that relaxes in opposition to the agonist

Question 24

Synergists

Answer 24

muscles that enable the agonists to operate more effectively.

Question 25

Fixator

Answer 25

muscles stop any unwanted movement by fixing or stabilising the joint or
joints involved.

Question 26

what is all or nothing law

Answer 26

For a muscle to contract it must receive a nerve impulse.all the motor neuron (nerve
Muscle fibres within the motor unit have to contract . It can not only be half of the muscle fibres cell.