Quick Revision

Question 1

What are the three types of muscle?

Answer 1

Cardiac muscle, smooth muscle and skeletal muscle

Question 2

What is the difference between the three types of muscle?

Answer 2

Neither cardiac nor smooth muscles are under conscious control, so we remain largely unaware of their contractions. However skeletal muscles make up the bulk of body muscle and act under voluntary control.

Question 3

Muscles are made up of millions of tiny muscle fibres, called _________.

Answer 3

Myofibrils.

Question 4

What are myofibrils?

Answer 4

Tiny muscle fibres that make up individual muscles.

Question 5

Why would a muscle was made up of individual cells joined end to end be inefficient?

Answer 5

Because the junction between adjacent cells would be a point of wellness and reduce the o weakly strength of the muscle.

Question 6

How is a muscle adopted, instead of having all its individual cells joined end to end?

Answer 6

The separate cells become fused together into muscle fibres.

Question 7

What is a sarcoplasm?

Answer 7

A muscle cell’s cytoplasm

Question 8

What are transverse (t) tubules?

Answer 8

Where the sarcolemma fold inwards across the ms or fibre and stick into the sarcoplasm.

Question 9

What is the sarcloemma?

Answer 9

The cell membrane of muscle fibres.

Question 10

What do T tubules do?

Answer 10

They help to spread electrical impulses throughout the sarcoplasm so they research all parts of the muscle fibre.

Question 11

The sarcoplasm contains a sarcoplasmic reticulum. What is this for?

Answer 11

This stores and releases calcium ions that are needed for contraction.

Question 12

Muscles that work together to move an incompressible bond are called antagonistic pairs.

The contracting muscle is called the ________.
Whilst the relaxing muscle is called the _________.

Answer 12

Contracting - agonist

Relaxing - antagonist

Question 13

Myofibrils contain…

Answer 13

• thin myofilaments: made of actin

- thick myofilaments: made of myosin

Question 14

What would a myofibrils look like under a microscope?

Answer 14

A pattern of alternating dark and light bands.

Question 15

In myofibrils, there are alternating dark and light bands. Outline the light bands.

Answer 15

lIght bands contain the thIn actin filaments only - the I-bands.

Question 16

In myofibrils, there are alternating dark and light bands. Outline the dark bands.

Answer 16

dArk bands contain the thick myosin filaments, and some overlapping thin actin filaments - A-bands.

Question 17

What is a Z-line?

Answer 17

The end of each sarcomere

Question 18

What is an M-line.

Answer 18

The muddle of each sarcomere.

Question 19

What is the H-zone?

Answer 19

Around the M-line is the H-zone. This contains only myosin filaments.

Question 20

How is muscle contraction explained?

Answer 20

By the sliding filament theory.

Question 21

Outline the sliding filament theory.

Answer 21

Myosin and actin filaments slide over one another to make the sarcomeres contract.
This simultaneous contraction means that the myofibrils and muscle fibres contract.
Sarcomeres return to their original length as the muscle relaxes.

Question 22

What is the primary response?

Answer 22

The production of antibodies, and memory cells produced by T and B cells.

Question 23

What is the secondary response?

Answer 23

Clonal selection occurs faster. Memory B cells are activated and divide into plasma cells that produce the appropriate r