Skeletal muscle cell structure

Question 1

True or False: A skeletal muscle is an organ

Answer 1

True

Question 2

What cells are responsible for muscle contractions?

Answer 2

skeletal myocytes

Question 3

What are the three types of muscles? Are they voluntary or involuntary?

Answer 3

1. Skeletal (voluntary)
2. Cardiac (involuntary)
3. Smooth muscle (involuntary)

Question 4

Is this correct:
Myocyte = Muscle Cell = Muscle Fibre

Answer 4

Yes

Question 5

What does the smooth er do in skeletal muscles?

Answer 5

Is serves as a calcium storage centre.

Question 6

What does the cytoskeleton do in skeletal muscles?

Answer 6

It enables the muscle cell to contract.

Question 7

What does a myofibril consist of?

Answer 7

Actin, Myosin, M line, Z line which all make up a sarcomere.

Question 8

True or False: Actin is the thick filament and Myosin is the thin filament

Answer 8

False: Myosin is the thick filament and Actin is the thin filament.

Question 9

True or False: Actin moves towards the M line of a sarcomere during contraction

Answer 9

True

Question 10

True or False: During contraction, the muscle gets shorter but it grows in diameter

Answer 10

True

Question 11

True or False: Most of the myofibrils contract synchronously in a healthy muscle cell

Answer 11

False: ALL myofibrils contract synchronously in a healthy muscle cell

Question 12

What factors implement how much force you can generate?

Answer 12

The number of myofibrils and/or the size of the myofibrils (greater # or size = more force generated)

Question 13

What does the endomysium surround?

Answer 13

It surrounds each individual muscle cell / myocyte / muscle fibre

Question 14

What type of tissue is the endomysium?

Answer 14

Loose connective tissue

Question 15

What does the perimysium surround?

Answer 15

It surrounds each individual muscle fascicle.

Question 16

What type of tissue is the perimusium?

Answer 16

Dense irregular connective tissue

Question 17

What does the epimysium surround?

Answer 17

It surrounds the entire skeletal muscle.

Question 18

What type of tissue is the epimysium?

Answer 18

Dense regular connective tissue

Question 19

True or False: The epimysium can be dense irregular connective tissue

Answer 19

True

Question 20

What else can be found in the a skeletal muscle?

Answer 20

Mitochondria, blood vessels, motor neurons, nucleus’

Question 21

What is the cell membrane of a muscle cell called?

Answer 21

sarcolemma

Question 22

What does a sarcomere do and where are they found?

Answer 22

Sarcomeres allow contraction in the muscle cell. They are found as repeating segments on a myofibril.

Question 23

What is the role of a neuromuscular junction?

Answer 23

It directly receives a signal from a neuron.

Question 24

What does a myofibril consist of?

Answer 24

Sarcomeres (Actin and Myosin)

Question 25

Role of nucleus?

Answer 25

Contains information that allows for the cell to produce more actin and myosin.

Question 26

What is the sarcoplasmic reticulum and what does it do?

Answer 26

It is the smooth er for muscle cells and it's role is to act as a calcium storage centre.

Question 27

What does myosin require in order to move actin towards the M line of a sarcomere?

Answer 27

ATP from the mitochondria

Question 28

list the microscopic to macroscopic order of a skeletal muscle with the tissues surrounding the structure.

Answer 28

1. Myofibril - contains sarcomeres 2. Muscle Fibre / Cell - surrounded by the endomysium made of loose connective tissue 3. Muscle Fascicle - surrounded by the perimysium made of dense irregular connective tissue. 4. Skeletal muscle - surrounded by the epimysium made of dense regular / irregular connective tissue depending on the muscle.

Question 29

List some functions of skeletal muscles:

Answer 29

All possible answers: - Movement - Posture - Breathing - Heat production - Control passage of certain substances (sphincters) - Mechanical protection of internal organs - Potassium storage K+ - Calcium storage Ca2+

Question 30

How are muscles attached to bones?

Answer 30

By tendons