Muscle Anatomy and Physiology

Question 1

What are the three types of muscles?

Answer 1

Skeletal, cardiac and smooth

Question 2

Define STRIATED MUSCLE TISSUE

Answer 2

Striated muscle tissue features repeating functional units called sarcomeres which are seen as a series of visible bands along the muscle fibres. Movement of these fibres is voluntary, aside from the heart. These muscle tissues fatigue rapidly.

Question 3

Define SMOOTH MUSCLE TISSUE

Answer 3

Smooth muscle tissue is found within the walls of hollow organs and are non-striated. Movement of these muscles is involuntary and they fatigue slowly.

Question 4

Define a TENDON

Answer 4

A tendon is a flexible but inelastic cord of strong fibrous collagen tissue attaching a muscle to a bone. Most tendons have white collagen which is inelastic.

Question 5

What is the role of a tendon?

Answer 5

• to connect muscle to bone

Question 6

What is the structure of a tendon?

Answer 6

It is made of a number of structures that all fit inside one another, which demonstrate how the tendon is able to retain its strength.
Tendon is made up of fascicle, fibril, subfibril, microfibril.

Question 7

Define the CRIMP

Answer 7

The crimp appears in tendons when collagen fibrils are parallel to each other and closely packed. They show a wave like appears and allow the tendon to have some flexibility. The bigger the crimp is, the more elastic the tendon is.

Question 8

Define a LIGAMENT

Answer 8

A ligament is a short band of tough, flexible fibrous connective tissue which connects two bones or cartilages or holds together a joint.

Question 9

What is the sarcoplasmic reticulum?

Answer 9

The sarcoplasmic reticulum is a network of tubules that extend through muscle cells. It regulates calcium concentration in the cytoplasm of striated muscle cells.

Question 10

Describe smooth muscle

Answer 10

It is regulated by to autonomic nervous system and influenced by hormone secretion. Non striated cylindrical cells with a nucleus.

Question 11

Describe cardiac muscle

Answer 11

This appears in the heart only and is striated.

Question 12

Describe skeletal muscle

Answer 12

Used voluntarily. Has many nuclei and is striated.

Question 13

What are the 4 muscle shapes?

Answer 13

Pennate, circular, parallel and convergent

Question 14

Describe a pennate muscle

Answer 14

Fibre groups radiate from one point. Fascicles are around 1 central tendon. They are strong but inflexible

Question 15

Describe a circular muscle

Answer 15

Sphincters, usually a junction. Their role is to open and close to let things in or out.

Question 16

Describe a parallel muscle

Answer 16

The fibres are parallel to the long axis. Their force is lower, so they are not the strongest, but they allow extension, meaning they can stretch.

Question 17

Describe a convergent muscle

Answer 17

One where the origin is wider than the insertion.

Question 18

What is the hierarchy of skeletal muscle?

Answer 18

Skeletal muscles have a hierarchical structure - the organ is comprised of fascicles which are composed of fibres. Fibres are composed of myofibrils. Myofibrils are made up of repeating units called sarcomeres. Sarcomeres are the functional unit of the muscle cell. Actin and myosin are found here.

Question 19

What are myofilaments?

Answer 19

The sarcomere is made of the myofilaments actin and myosin. Actin is the thin filament and myosin is thick filament. They both work together to allow muscle physiology and movement.

Question 20

Define a NERVE CELL

Answer 20

A nerve cell is a neurone, and its job is to make messages travel by sending electrical messages that travel across cell membranes.

Question 21

What is the synaptic system?

Answer 21

1. Electric message is sent along the neurone
2. It meets the gap (the synapse) and jumps across
3. It notifies the next nerve cell to move the message along

Question 22

What does the CNS control?

Answer 22

The brain (forebrain, midbrain and hindbrain) and the spinal cord.

Question 23

What does the PNS control?

Answer 23

The somatic (voluntary) and autonomic (involuntary) nervous systems as well as the sympathetic and parasympathetic nervous systems.

Question 24

What is the function of muscles?

Answer 24

• to produce movement
• to maintain postures and positions
• to keep joints stable
• to control cavity pressure (drawing in/expelling air)
• to maintain body temp. (shivering)
• controls exits and entrances to the body
• energy storage

Question 25

Define a SARCOMERE

Answer 25

A sarcomere is the functional unit of the muscle cell.

Question 26

What are the regions of the sarcomere?

Answer 26

• A band, in the middle
• I band is near the edges and is only ever actin
• H band is in the middle of A and is only ever myosin
• Z lines identify the start and the end of the sarcomere
  Actin is secured to the Z line by alpha atin and myosin is secured to the Z line by titin.

Question 27

What is sliding filament theory?

Answer 27

Actin and myosin do not shorten and instead they slide past one another to shorten the sarcomere. As a result, the whole muscle contracts. I band shortens, H band shortens, A band stays the same.

Question 28

What are the properties of muscle?

Answer 28

Contractibility, excitability, extensibility, elasticity

Question 29

Define INNERVATION

Answer 29

Innervation is the process of supplying nerves to something.