Chapter 1F - Neuroendocrine Physiology

Question 1

What does the endocrine system do?

Answer 1

Endocrine system releases hormones that regulate physiological processes and maintain homeostasis when the body is confronted with external stimuli or environmental stressors.

Question 2

The endocrine system releases hormones that relate what?

Answer 2

The endocrine system releases hormones that regulate blood glucose levels, metabolism, tissue growth, recovery, mood and reproduction

Question 3

What are hormones? Where are they created, stored, and released?

Answer 3

Hormones are chemical messengers that are produced by endocrine glands and other specific cells, which are created, stored and released into the blood to stimulate specific physiological responses.

Question 4

What are the three different types of classification of hormones?

Answer 4

• Fat-soluble steroid hormones (cortisol and testosterone)
• Polypeptide hormones (insulin and growth hormone)
• Amine hormones (dopamine, noepinephrine and epinephrine)

Question 5

Explain fat soluble hormones.

Answer 5

Ex - Cortisol and testosterone. Passively diffuse across cell membrane and are responsible for primary and secondary sex characteristics, and are involved in metabolic control, immunity, fluid balance and inflammation

Question 6

Explain polypeptide hormones

Answer 6

Ex. - insulin and growth hormones. Made of chains of amino acids inside the nucleus of cells. because they aren’t fat soluble they serve as secondary messengers, signaling other hormones and hormonal cascades

Question 7

Explain Amine hormones?

Answer 7

Amine hormones consist of the amino acids tyrosine (ex. dopamine, norepinenphrine, and epinephrine) and trytophan (ex. serotonin) Amine hormones bind to membrane receptors and work via secondary messengers.

Question 8

What’s the difference between anabolic and catabolic hormones? This is another way hormones can be classified.

Answer 8

Anabolic hormones promote tissue building and catabolic hormones break down cellular components.

Question 9

Hormones are complicated in how they work, but one way to explain them is the lock and key principle, also what is cross reactivity and allosteric binding, explain?

Answer 9

Lock and key principle refers to a binding mechanism of hormones and enzymes where the hormones receptor site has a specific structure that allows a single hormone to bind to the site.

Cross-reactivity occurs when a hormone fits the receptor but needs to interact with other hormones to produce a response.

Allosteric binding - some receptors have this where substrates other than the specific hormone can increase or decrease the response to the primary hormone via feedback loops.

Question 10

Name three anabolic hormones (building you up) that are involved in muscle remodeling and growth.

Answer 10

Testosterone, growth hormone, and insulin-like growth factors are the primary anabolic hormones involved in muscle remodeling and growth

Question 11

Explain testosterone! Is it in both males and female. In what part of the body is in produced in males in females?

Answer 11

Testosterone - It is the primary male androgen (sex hormone) in human physiology. Boths males and females are impacted by it.

Males have much higher levels.

It increases protein synthesis, the rate of cellular metabolism, and RBC production.

It’s produced by the testes in males and the ovaries and adrenal glands in females.

Question 12

Explain growth hormone. Where is it secreted? What is it responsible for? What are some maybe lesser known / other functions of growth hormone?

Answer 12

Secreted in the anterior pituitary gland, which has a significant influence on metabolism and energy availability.

Responsible for increasing the uptake of amino acids in skeletal muscle, and for increasing protein synthesis, facilitating the growth of type I and type II muscle fibers.

Other functions - decreasing glucose utilization and glycogen synthesis, increasing the availability of glucose and amino acids, increasing collagen synthesis, and cartilage growth, and enhancing the immune cell function.

Question 13

Explain insulin like growth factors and what they do. What body parts/organs produce insulin like growth factors.

Answer 13

The majority of the growth-promoting effects of growth hormone are indirectly controlled by IGFs.

These growth promoting proteins are produced by skeletal muscle, bone, the liver, and other tissues.

Stimulates amino acid uptake from the blood to be used for cellular proteins and the uptake of sulfur needed for the cartilage matrix.

Question 14

Adrenal hormones , name two of them and what is the main function of adrenal hormones.

Answer 14

Hormones produced by the adrenal glands (which are located right above the kidney) play a critical role in the fight or flight response and are also responsive to exercise stress.

Cortisol and catechoamines are two examples of adrenal hormones and are most important for exercise training.

Question 15

Explain Cortisol. Is it anabolic or catabolic? What is its principle role? How does it impact glucose? What can cause chronically high levels of cortisol and what will that potentially result in?

Answer 15

A glucocorticoid secreted by the adrenal cortex, is a catabolic hormone in skeletal muscle.

Principle role is to ensure that energy is available.

Primary signaling hormone for carb metabolism and is associated with the storage of glycogen in muscle tissue.

Also increases production of glucose in the liver and glycogen production in skeletal muscle.

Overtraining can cause chronically high levels of cortisol, which can result in loss of strength and lean muscle mass.

Question 16

Explain Catecholamines? Name three of them, and what are they secreted by?

Answer 16

Epinephrine, noepinephrine and dopamine are secreted by the adrenal medulla.

In muscle epinephrine and norepinephrine increase muscle blood flow due to vasodilation, elevate blood pressure, increase the rate of muscle contraction, increase energy availability, enhance metabolic enzyme activity, and increase testosterone secretion rates.

Question 17

For Acute anabolic hormone response, what happens for up to 30 minutes after anaerobic resistance training?

Hormone levels are elevated most with resistance exercises that utilize small or large muscle groups? high or low intensity? and short or long rest intervals?

What happens to concentration of catechloamines?

Answer 17

For up to 30 minutes after anaerobic resistance training, testosterone, growth hormone and cortisol concentrations are elevated. Changes occur rapidly and are stabilized as body responds to homeostatic challenges associated with acute and long-term exercise training.

Large muscle groups being involved raise hormone levels the most, mod-high volume exercise and short rest breaks do the same.

Catechloamine ( epinephrine, norepinephrine, and dopamine) concentrations are associated with the regulation of force production, energy availability, and the rate of muscle contraction, and increased concentrations of testosterone and other hormones.

Question 18

Explain the chronic changes in acute hormone responses with training/exercise? Is the body able to adopt to better handle anaerobic training over time?

Answer 18

Changes in endocrine function correspond to the increased exercise stress that the body is capable of handling.

Any chronic adaptations in hormonal response patterns to acute anaerobic exercise may enhance the athlete’s ability to handle and maintain higher-resistance exercise intensities for longer time periods.

Question 19

Chronic changes in resting hormone concentrations after anaerobic exercise?

Is there a change that happens in resting hormone concentration after training for multiple months?

Elevated levels of hormones after training impact.

Answer 19

Chronic changes in resting hormone concentrations after anaerobic exercise have not consistently been found with growth hormone, testosterone, or insulin like growth factors.

Resting state hormone concentrations likely reflect factors such as muscle tissue response to intensity or volume changes in the resistance training program.

Elevated levels of hormones after resistance training are great enough to influence muscle tissue remodeling.

Question 20

Steroids and their impact on hormones at rest? Down-regulation?

Answer 20

Chronically high levels of anabolic steroids can be detrimental, causing down regulation

Down-regulation - (decreased number of receptors on target cell surface) of hormone receptors.

Athletes using such performance enhancers try to combat this by cycling the drugs.

Question 21

Hormone response to resistance training?

Answer 21

Hormone receptor changes have been shown to occur in response to resistance training.

Androgen (testosterone) receptors seem to be upregulated within 48-72hrs after training.

Changes in receptors mediate adaptations stimulated by hormonal responses.

Question 22

How can we increase serum testosterone with exercise, what exercises, reps, rest periods?

Answer 22

Perform exercises such as squats, bench press, dead lift and cleans which target large muscles.

Heavy loads that are 85-95% of one rep max

Performing multiple exercises or multiple sets to acheive moderate to high volume.

Short rest breaks of 30-60sec

Question 23

How can we increase growth hormone via training methods.

Answer 23

Perform 3 sets of each exercise at high intensity with short rest breaks (under 1 min)

Consume carbs and protein before and after resistance training sessions.

Question 24

How can we achieve optimal adrenal hormone response with training.

Answer 24

Perform high-voume resistance exercises that utilize large muscles combined with short rest periods. This causes adrenergic stress.

Note: Adequate rest and a varied training protocol should be utilized to avoid this stress leading to nonfunctional overreaching or overtraining.

Question 25

Hormonal responses to aerobic exercise?

Answer 25

High intensity aerobic training enhances the secretion of hormones in response to max aerobic exercise. Response likely improves the athlete’s ability to handle and maintain high aerobic exercise intensities over a long period of time.