Module 5 : Types of muscles and structure of skeletal muscle

Question 1

What are the 3 types of muscle in the body?

Answer 1

skeletal muscle
cardiac muscle
involuntary muscle( smooth muscle)

Question 2

Skeletal muscle cells are responsible for …

Answer 2

movement

Question 3

Cardiac muscle cells are known as …

What does this mean?

Answer 3

myogenic

means they can initiate their own contractions without nervous stimulation to maintain a regular heart rhythm

Question 4

State 3 locations where involuntary(smooth) muscle can be found?

Answer 4

-in the walls of hollow organs
-in walls of blood vessels
-in walls of the digestive tract

Question 5

State the fibre appearnace for skeletal , cradiac and smooth muscle

(is it striated/ non striated)

Answer 5

skeletal-striated
cardiac-specialised striated
smooth-non striated

Question 6

Say whether cardiac , skeletal and smooth muscle are under conscious or involuntary control

Answer 6

skeletal-conscious
cardiac and smooth-involuntary

Question 7

Describe the arrangements of each type of muscle and the direction of their contractions

-one sentence for each

Answer 7

skeletal-regular arrangement so muscle contracts in one direction

cardiac-cells branch and interconnect resulting in simultaneous contraction

smooth-no regular arrangement so cells can contract in different directions

Question 8

State the speed and length of contractions for each type of muscle

Answer 8

skeletal-rapid speed and short length of contraction

cardiac-intermediate speed and length of contraction

smooth-slow speed and can remain contracted for relatively long time

Question 9

Skeletal muscle is made up of bundles of …

Answer 9

muscle fibres

Question 10

The plasma membrane of muscle fibres is known as the …

Answer 10

sarcolemma

Question 11

Muscle fibres form as a result of …

What does a muscle fibre contain a lot of ?

Answer 11

many individual muscle cells fusing together

nuclei

Question 12

The shared cytoplasm in a muscle fibre is called the …

Answer 12

sarcoplasm

Question 13

The folding of sections of the sarcolemma forms what structures?

What do these structures do?

Answer 13

T - tubules

they help spread electrical impulses through out the sarcoplasm

Question 14

Why do muscle fibres contain lots of mitochondria?

Answer 14

to provide ATP which the muscles require in order to contract

Question 15

What is the name given to the specialised endoplasmic reticulum that muscle fibres contain?

What ions does it contain and why?

Answer 15

sarcoplasmic reticulum

contains calcium ions that are also required for muscle contraction

Question 16

Each muscle fibre contains many …

Answer 16

myofibrils

Question 17

Name the 2 types of protein filament that make up myofibrils

Briefly describe their structures

Answer 17

actin-the thinner filament , consists of 2 strands twisted around each other

myosin-the thicker filament , consist of long rod shaped fibres with bulbous heads that project to one side

Question 18

Name the 2 different bands within a myofibril
Describe them

Answer 18

I band-appears light as its the region where actin and myosin filaments do not overlap

A band-appears dark as it contains think myosin filaments

Question 19

What is the Z line in a myofibril?

What is the name given to the distance between 2 adjacent Z lines?

Answer 19

a line in the centre of each light ( I ) band

a sarcomere

Question 20

What is the H band ?
Which type of protein filament is present here?

Answer 20

the lighter region found in the centre of each dark ( A ) band

myosin filaments only

Question 21

What is a sarcomere ?

Answer 21

the functional unit of a myofibril
it shortens when muscles contract