Chp.2 - Basic Exercise Science - Muscular&Endocrine

Question 1

Describe the structure of the SKELETAL MUSCLE.

Answer 1

• muscle fibers in muscle fibers.
• the WHOLE muscle is wrapped by the fascia and the EPIMYSIUM
• bundle of muscle fibers(fascicle) inside the muscle is wrapped by the PERIMYSIUM
• fascicles individual muscle fibers are wrapped by ENDOMYSIUM.
• -> epi, peri, endo

Question 2

What are tendons?

Answer 2

• CONNECTIVE TISSUE that attaches MUSCLE to BONE, and provides ANCHOR for muscles to produce FORCE.

Question 3

Explain what MUSCLE FIBERS are.

Answer 3

• muscle fibers are cells that have structures called MYOFIBRILS that provide the contractile component.
  The myofibrils are made up of SARCOMERES.

Question 4

What is a sarcomere?

Answer 4

• functional UNIT of the muscle (e.g. neuron is to NS); produces muscle CONTRACTION and consists of REPEATING sections of ACTIN(thin) and MYOSIN(thick filaments)

Question 5

Explain the NEURAL ACTIVATION of muscles.

Answer 5

• skeletal muscles won’t contract unless stimulated to do so by MOTOR NEURONS. At the neuromuscular junction, neurotransmitters are released and link with receptor sites on the muscle fiber.

Question 6

Explain the different MUSCLE FIBER TYPES.

Answer 6

• slow twitch: smaller, more resistant to fatigue, more mitochondria, for long term contractions “red fibers”
• fast twitch: larger, tires out more easily, quick to produce maximal tension e.g. sprint
• ALL muscles have a COMBINATION of SLOW and FAST twitch fibers.

Question 7

Talk about the primary ENDOCRINE GLANDS (4)

Answer 7

• pituitary and hypothalamus (located in brain; “master glands”)
• adrenal and thyroid

Question 8

Talk about the relationship between exercise and INSULIN and GLUCAGON.

Answer 8

• (note: insulin and glucagon regulated blood glucose levels and are produced by pancreas)
• note: glucose is stored as glycogen in the liver and muscle
• insulin levels drop during physical activity and glucagon secretion increase in order to maintain steady supply of blood glucose.

Question 9

Talk about the relationship between exercise and the adrenal, pituitary, reproductive and thyroid hormones.

Answer 9

• epinephrine & norepinephrine: increases heart rate, blood glucose levels, opens airways…
• (adrenal)cortisol: muscle breakdown, stress
• raised level of testosterone: +growth and repair of tissue
• estrogen: fat deposition around hips, buttocks, thighs
• (pit.)growth hormone: increases fat burning, strengthens immune
• thyroid hormones: metabolism, body temp, protein synthesis…

Question 10

What does the endocrine system consist of?

Answer 10

• the endocrine system consists of GLANDS, HORMONES and RECEPTOR CELLS.

Question 11

What is muscle connective tissue important?

Answer 11

• plays a VITAL role in movement, TRANSMIT the FORCE from muscle CONTRACTION to bones, helps form the TENDON.

Question 12

What is a motor unit?

Answer 12

• 1 motor neuron + muscle fibers it connects

Question 13

What is the neurotransmitter used by the neuromuscular system?

Answer 13

• aceltylcholine (ACh)

Question 14

Types of muscles (as movers)? (4)

Answer 14

• agonist muscles - prime movers
• synergist muscles - assist prime movers
• stabilizer muscles
• antagonist muscles - perform opposite action of prime mover.

Question 15

What is the primary energy source during vigorous exercise?

Answer 15

• carbohydrates (spec. glucose)