Exam 2

Question 1

What is hormone-receptor interaction?

Answer 1

Hormones interact with specific receptors on target cells, leading to a biological response. This interaction is crucial for the hormone’s effects and is often compared to a lock and key mechanism.

Question 2

What factors influence hormone concentration in the blood?

Answer 2

Factors include the rate of hormone secretion, rate of metabolism or excretion, quantity of transport proteins, and changes in plasma volume.

Question 3

How do steroid hormones function?

Answer 3

Steroid hormones enter cells, bind to intracellular receptors, and directly influence gene expression by interacting with DNA, leading to protein synthesis.

Question 4

What is the second messenger hypothesis?

Answer 4

Non-steroid hormones bind to surface receptors, activating a second messenger inside the cell (e.g., cAMP), which then triggers the cellular response.

Question 5

What is an amplifying cascade?

Answer 5

Hormone binding triggers a chain of events inside the cell, where each step amplifies the initial signal, leading to a large cellular response from a small hormonal stimulus.

Question 6

What is the G-protein/adenylate cyclase/cAMP system?

Answer 6

This system involves hormone binding to a receptor, activating G-proteins, which then activate adenylate cyclase. Adenylate cyclase converts ATP to cAMP, which acts as a second messenger to activate protein kinase A.

Question 7

What is the calcium and calmodulin second messenger system?

Answer 7

This system allows calcium ions to bind to calmodulin, which activates various intracellular processes, particularly during muscle contraction.

Question 8

What are hypothalamus-releasing factors?

Answer 8

These factors control hormone secretion from the anterior pituitary gland by releasing hormones into the bloodstream, which then act on the pituitary.

Question 9

How does the hypothalamus control the posterior pituitary?

Answer 9

The hypothalamus directly controls the secretion of hormones (like oxytocin and vasopressin) from the posterior pituitary via nerve signals.

Question 10

What are the sites, stimuli, and actions of key hormones?

Answer 10

Epinephrine & norepinephrine increase heart rate and blood glucose; glucagon increases glucose release from the liver; insulin promotes glucose uptake; cortisol mobilizes energy stores; aldosterone regulates blood pressure; thyroxine controls metabolic rate; growth hormone promotes growth; estrogen & testosterone regulate reproductive function.

Question 11

What is the role of testosterone and growth hormone in muscle growth?

Answer 11

Both promote muscle growth; however, excessive use of anabolic steroids (testosterone) can have severe side effects, including heart issues and hormonal imbalances.

Question 12

How do catecholamines affect glycogen mobilization?

Answer 12

Plasma catecholamines (epinephrine, norepinephrine) activate the cAMP system to mobilize glycogen, while intracellular calcium-calmodulin influences glycogenolysis during muscle contraction.

Question 13

What are the mechanisms of blood glucose homeostasis?

Answer 13

They include mobilization of liver glycogen, mobilization of free fatty acids from adipose tissue, gluconeogenesis in the liver, and blocking glucose entry into cells.

Question 14

What changes occur in hormones during exercise?

Answer 14

Insulin decreases while glucagon, cortisol, growth hormone, epinephrine, and norepinephrine increase, helping maintain blood glucose levels.

Question 15

What are fast-acting vs. slow-acting hormones?

Answer 15

Fast-acting hormones (e.g., epinephrine, norepinephrine, insulin, glucagon) rapidly adjust glucose levels, while slow-acting hormones (e.g., cortisol, growth hormone) help sustain energy balance over longer periods.

Question 16

How do hormone levels affect free fatty acid mobilization?

Answer 16

Decreased insulin and increased catecholamines enhance the mobilization of free fatty acids from adipose tissue for energy.

Question 17

What is the organization of the nervous system?

Answer 17

The nervous system is divided into the central nervous system (CNS: brain and spinal cord) and peripheral nervous system (PNS: sensory and motor neurons).

Question 18

What is the structure and function of a nerve?

Answer 18

A nerve is composed of bundles of neurons that transmit signals, consisting of a cell body, dendrites (which receive signals), and an axon (which sends signals).

Question 19

What is the withdrawal reflex pathway?

Answer 19

It involves sensory neurons detecting pain, sending signals to the spinal cord, where interneurons activate motor neurons to withdraw the body part from danger.

Question 20

What are depolarization, action potential, and repolarization?

Answer 20

Depolarization is when the cell membrane becomes less negative; action potential is a rapid electrical signal that travels along the axon; repolarization is the return to resting state after the action potential.

Question 21

What are position receptors?

Answer 21

Proprioceptors (like muscle spindles and Golgi tendon organs) detect body position and movement, helping to control movement and maintain balance.

Question 22

What is the role of the vestibular apparatus?

Answer 22

Located in the inner ear, it helps maintain balance and equilibrium by detecting changes in head position and motion.

Question 23

What brain centers are involved in voluntary movement?

Answer 23

The motor cortex, basal ganglia, and cerebellum coordinate and initiate movement.

Question 24

What is the autonomic nervous system?

Answer 24

It controls involuntary bodily functions (e.g., heart rate, digestion) and is divided into the sympathetic (fight-or-flight) and parasympathetic (rest-and-digest) systems.

Question 25

What is the microstructure of skeletal muscle?

Answer 25

Muscle fibers contain myofibrils, composed of repeating sarcomeres (the contractile units), with key components including actin and myosin filaments.

Question 26

What are satellite cells?

Answer 26

Stem cells involved in muscle repair and growth, residing outside the muscle fiber but can donate their nuclei to aid muscle regeneration.

Question 27

What is the myonuclear domain?

Answer 27

The region of cytoplasm governed by a single nucleus within a muscle fiber, crucial for muscle growth and repair.

Question 28

What is the chain of events in muscular contraction?

Answer 28

An action potential travels down a motor neuron, calcium is released from the sarcoplasmic reticulum, calcium binds to troponin, allowing actin and myosin to interact and cause contraction.

Question 29

What is the difference between dynamic and static exercise?

Answer 29

Dynamic exercise involves movement (e.g., running), while static exercise involves sustained muscle contraction without movement (e.g., plank).

Question 30

What factors determine force production in muscles?

Answer 30

Factors include the number of motor units recruited, frequency of motor unit firing, and initial muscle length (optimal length allows for maximum force production).

Question 31

What are the human skeletal muscle fiber types?

Answer 31

Type I (slow-twitch): High endurance, low force; Type IIa (fast-twitch oxidative): Intermediate endurance and force; Type IIx (fast-twitch glycolytic): Low endurance, high force.

Question 32

How does movement velocity relate to force?

Answer 32

As velocity of contraction increases, the force exerted decreases. Optimal force production occurs at intermediate speeds.

Question 33

Released from the adrenal medulla, increase during stress or exercise, raising heart rate and blood glucose.

Answer 33

Epinephrine & norepinephrine:

Question 34

From the pancreas, stimulated by low blood sugar, increases glucose release from the liver.

Answer 34

Glucagon

Question 35

From the pancreas, stimulated by high blood glucose, promotes glucose uptake by cells.

Answer 35

Insulin

Question 36

From the adrenal cortex, stimulated by stress or exercise, mobilizes energy stores.

Answer 36

Cortisol

Question 37

From the adrenal cortex, helps regulate blood pressure by controlling sodium and water balance.

Answer 37

Aldosterone:

Question 38

From the thyroid gland, controls metabolic rate.

Answer 38

Thyroxine:

Question 39

From the anterior pituitary, promotes growth and mobilizes fat stores.

Answer 39

Growth hormone:

Question 40

From the ovaries/ testes, regulate reproductive function and influence muscle growth.

Answer 40

Estrogen & testosterone:

Question 41

Fiber type distribution influences performance in different sports (e.g., endurance vs. power sports).

Answer 41

Athletic performance: