Endocrine System Flashcards
what is the purpose of the endocrine system?
supports the normal homeostatic function of the human body and helps it respond to external stimuli
why is it important for strength and conditioning professionals to have an understanding of the endocrine system?
increases insight into how an exercise prescription can enable hormones to mediate optimal adaptations to resistance training
what is the only natural stimulus for increases in lean tissue mass?
resistance training
changes in hormonal concentrations following exercise effect what?
tissue adaptations
what are hormones?
chemical messengers that are synthesized, stored, and released into the blood by endocrine glands
Endocrine glands
body structures specialized for secretion
neuroendocrinology
the study of the interactions between the nervous system and the endocrine system
what are 3 mechanisms of hormone secretion?
1) secretion into the blood
2) Autocrine secretion
3) paracrine secretion
what is autocrine secretion?
cell releases the hormone inside the cell itself- hormone does no leave the cell it was produced in
what is paracrine secretion?
cell releases hormone to adjacent cells-circulation not needed to put hormone in contact with target cell
name an unusual characteristic of skeletal muscle
it has multinucleated cells
why is multinucleate cells significant in muscle cells?
different parts of the cell are regulated by different nuclei (domains). this allows for differential regulation of protein metabolism along the length of a muscle fiber
what body systems are involved in remodeling muscles?
endocrine, nervous, and immune
what is the most prominent resistance training adaptation in the muscle?
increase in the amount of a muscle’s contractile proteins: actin and myosin
2 important steps in muscle growth:
increase in protein synthesis and decrease in protein degradation
what muscle fiber type depends more on decrease in protein degradation for growth?
type I
what muscle type depends more on increased protein synthesis?
type II
anabolic hormones
hormones that promote tissue building and block the negative effects of catabolic hormones
catabolic hormones
hormones that promote the degrading of tissue (protein to support glucose synthesis)
what is a T/C Ration?
ration of testosterone to cortisol
with relation to the T/C ration, what will happen with more stressful training sessions?
the ratio will decrease
what may happen to the T/C ration if an athlete multiple high stress training sessions without sufficient recovery?
this ration may be chronically low- chronically high levels of cortisol
what effect does testosterone have on motor neurons?
1) Increase MU recruitment and force production
2) increase size of nerve cell body
how does testosterone enter the cell?
diffuse across cell membrane and bind to androgen receptors
what hormone initiates genes to increase protein synthesis and satellite cell fusion?
testosterone
testosterone in the blood
most is bound to proteins- 2% is free
what hormones does the medulla of the adrenal glands secrete?
Epinephrine & Norepinephrine
what hormones does the cortex of the adrenal glands secrete?
corticosteroids: glucocorticoids and cortisol
name the 3 lobes of the pituitary gland
1) anterior
2) intermediate
3) posterior
Non-steroid hormones interact with cell by…
lock & key: certain hormones bind to specific receptors causing either a direct effect or initiating a secondary cell messenger
where is growth hormone secreted from?
anterior pituitary gland
name 6 metabolic actions growth hormone induces
1) increase in triglyceride breakdown
2) glucose output by liver
3) decrease in muscle glucose uptake
4) increase in blood fatty acids
5) increase in fat metabolism
6) increase in blood glucose
what are 2 relevant effects of growth hormone stimulation?
protein synthesis and lengthening/thickening of bones
lipid based hormones are ___________, which means _____________
hydrophobic; they are lipid soluble and can diffuse across cell membrane
protein based hormones are ____________, which means ___________
hydrophillic; they need receptors to interact with the cell
name the 2 classes of hormones
peptide and steroid
what are the 2 main hormones secreted by the pancreas
Insulin and Glucagon
Men have _______ times more testosterone than women
10-20
are the functions of testosterone largely catabolic or anabolic? explain
anabolic. Testosterone is responsible for stimulating growth and development
where is cortisol produced?
adrenal gland
what are the functions of cortisol? (anabolic or catabolic)
catabolic
what does cortisol stimulate?
conversion of proteins to carbohydrates
describe the effects of cortisol with regards to resistance training
effects are the opposite of resistance training goals. (ex: protein conversion), therefore chronically high levels of cortisol are detrimental. (acute effects are fine- help in tissue reformation)
What hormones are involved with “flight or fight” response?
epinephrine and norepinephrine
what are the 2 types of glands?
exocrine: secrete to ducts
endocrine: secrete into the bloodstream
