Endocrine Responses to Resistance Exercise Flashcards
What is GAS?
- Alarm
- Resistance
- Exhaustion
What are hormones?
Hormones are the chemical messengers that we synthesize, store, and release to the blood from our endocrine glands and other specific cells.
Name the main sites of hormone secretion (10):
Hypothalamus Pituitary gland Thyroid gland Parathyroid gland Heart Liver Adrenal glands Pancreas Kidneys Testes/Ovaries
What are the two main types of hormones? Explain each:
Anabolic hormones are the hormones used to build tissues. The main ones are insulin, insulin-like growth factors, testosterone, and growth hormone.
Catabolic hormones are the hormones that degrade cell proteins. Examples of this are cortisol and progesterone.
Explain how hormones interact with receptors
Signals can only be used by the cells that contain receptors for that specific hormone. This makes sure that only target cells are affected by the hormones released in the body. Many of the body’s hormones are unable to cross cell membranes, so the signal is relayed in the cell via secondary messengers.
We call the principle of hormones going to specific cell receptors a Lockand-key theory. The receptor is the lock, and the key is the hormone. When hormones are unable to connect to a receptor, it is called downregulation.
What are the 3 main hormone categories? List only
Steroids
Polypeptides
Amine
What are steroid hormones?
These hormones come from the adrenal cortex and the gonads.
They are fat soluble hormones and they diffuse through cell membranes passively.
After the steroids diffuse through the membrane, they bind with the receptor and make a hormone-receptor complex. This activates the receptor. The hormone receptor complex moves to the nucleus where it interacts with the DNA in order to synthesize certain proteins.
What are polypeptide hormones?
These hormones are made of amino acid chains.
They are unable to cross cell membranes, as they are not fat soluble. Because of this, when they bind to receptors on the cell membrane, they cause the secondary reactions in the cell to cascade and eventually achieve its goal.
What are amine hormones?
These hormones are made up of the amino acid tyrosine or tryptophan.
They act like the polypeptides in the sense that they bind to the wall and cause secondary reactions within the cell.
Name the 3 main anabolic hormones (list only):
Testosterone
Growth Hormone (GH)
Insulin-like Growth Factors (IGFs)
Tell me about testosterone…
The main androgen hormone that interacts with skeletal muscle tissues. It causes growth hormone responses that lead to the synthesis of proteins, increases in size and strength, and increases in the potential for force production and muscle mass.
Men have 15 to 20 times more testosterone than women do. Exercising large muscle groups leads to acute increases in serum testosterone in men.
Tell me about growth hormone…
This hormone mainly interacts with bone, immune cells, skeletal muscle, fat cells, and liver tissue.
It is regulated by neuroendocrine feedback and mediated by the secondary hormones. If used pharmaceutically its effects are not known and very unpredictable.
Tell me about IGFs…
They are known for their role in protein anabolism. Exercise increases IGF blood levels acutely.
Tell me about cortisol…
Cortisol is a catabolic hormone. It is used to convert amino acids into carbohydrates, increase levels of enzymes that break down proteins, and to inhibit protein synthesis.
When we do resistance exercise, there are typical responses we have to cortisol levels.
They include:
- an increase in cortisol following sessions
- a reduction in the negative effects of the increases in cortisol
- increases in serum values when doing high volume, large muscle group, short rest period exercise.
There are big differences seen in the psychological role of cortisol in acute and chronic responses.
Tell me about catecholamines…
Catecholamines (the most common are epinephrine, norepinephrine, and dopamine) have certain roles.
They increase the force production, metabolic enzyme activity, muscle contraction rate, blood pressure, availability of energy, and blood flow. Catecholamines also augment secretion rates of other hormones.
There are some typical training adaptations of catecholamines. Heavy resistance training may increase athlete’s ability to put out more epinephrine with max exercise.
Training protocols need to be varied for adrenal glands to recover and for them to prevent cortisol’s secondary responses. These secondary responses may have negative effects on the immune systems and the protein structures.
