Muscle Tissue & Skeletal Muscles

Question 1

Describe four functions of muscle tissue?

Answer 1

• Produce movement
• Maintain posture and stabilise joints & body positions
• Storing and moving substances in the body
  Regulates organ volumes and act as sphincters
  Moves blood, urine, air, food & fluids, sperm
• Skeletal muscle contraction produces heat

Question 2

Describe three functional characteristics of muscle tissue?

Answer 2

• Electrical excitability
• Contractility
• ## Extensibility

Question 3

Name the three types of muscle?

Answer 3

• Smooth
• Cardiac
• Skeletal

Question 4

State the location and function of the Cardiac muscle?

Answer 4

• Function: pump blood

- Location: heart

Question 5

State the location and function of smooth muscle?

Answer 5

• Function: regulates the diameter of blood vessels
  and airways propels food in GI (digestive) tract
• Location: Walls of blood vessels, GI tract, airways.

Question 6

State the location and function of Skeletal muscle?

Answer 6

• Function: to produce skeletal movement

- Location: attached to bones

Question 7

Explain what happens at the neuromuscular junction?

Answer 7

Neuromuscular junction is the site of chemical communication between a nerve fibre and a muscle cell. Upon stimulation by a nerve impulse, the terminal releases the chemical neurotransmitter acetylcholine from synaptic vesicles

Question 8

Name the specific neurotransmitter that causes skeletal muscle contraction?

Answer 8

Acetylcholine (ACh)

Question 9

Describe how skeletal muscle contraction occurs?

Answer 9

Muscle contraction occurs through the movement of contractile proteins

Question 10

Name the two contractile proteins involved in muscle contraction?

Answer 10

• Thin actin filaments

- Thick myosin filaments

Question 11

Describe the difference between skeletal muscle contraction and smooth muscle contraction?

Answer 11

Smooth muscle contraction starts more slowly & lasts longer (relaxes more slowly) than skeletal muscle

Question 12

Explain the term muscle tone and define hypertonia and hypotonia?

Answer 12

Hypotonia - When motor neurons that control skeletal muscles are damaged the muscle becomes flaccid or limp because muscle tone is lost.
Hypertonia - Increased muscle tone results from damage to the motor neurons that supply the muscle

Question 13

Describe the term atrophy and give an example of what causes it?

Answer 13

• Wasting away of muscles

- Caused by disuse of the muscle or severing of the nerve supply

Question 14

Describe the term hypertrophy and give an example of what causes it?

Answer 14

Hypertrophy is the increase in the diameter of muscle fibres
resulting from very forceful, repetitive muscular activity
- E.g. body builders have enlarged skeletal muscles
- Left ventricular hypertrophy is enlargement of the left ventricle of the heart and results from increased workload of the heart either from physical exercise or disease

Question 15

Describe the difference between a tendon and a ligament?

Answer 15

A tendon is a fibrous connective tissue which attaches muscle to bone. … A tendon serves to move the bone or structure. A ligament is a fibrous connective tissue which attaches bone to bone, and usually serves to hold structures together and keep them stable

Question 16

Describe the main age related change that occurs to muscle tissue?

Answer 16

• A slow, progressive loss of skeletal muscle mass
• Skeletal muscle is replaced by fibrous connective tissue & fat
• Decreased muscle strength (due to less muscle mass)
• Decreased smooth muscle tone (think about digestive function & blood pressure)
• Decreased muscle and postural flexibility (due to loss of extensibility of muscle tissue)
• Decreased reflexes (due to slower neuron function

Question 17

Name three muscles used for IM (intramuscular) injections?

Answer 17

• gluteus medius
• lateral quadriceps
• deltoid muscles