Ex Phys Chapter 4 Hormonal Control During Exercise

hormones

any chemical that controls and regulate the acitivty of certain cells or organs

hormones are transported to specific ____ _____ - cells that possess specific hormones receptors

target cells

steroid hormones

hormones that have chemical structure similar to cholesterol. Soluble in lipids which causes them to easily diffuse through cell membranes

what hormones are considered steroidal hormones

testosterone, estrogen, progesteron, cortisol and aldosterone

non-steroid hormones

not lipid soluble hormones so they cannon easily cross cell membranes. can be divided into two groups: protein/peptide hormones and amino acid-derived hormones

(non-steroid) Peptide C protein hormones

derived from chains of amino acids. water soluble, cannot pass through cell membrane so they bind to surface temporarily.

(non-steroid) amino acid-derived hormones (amines)

derived from modified single amino acids. Can be water soluble (like epinephrine) or lipid-soluble (like thyroid hormones).

examples of peptide C protein hormones

insulin, growth hormone, oxytocin, ADH, FSH, TSH

examples of amino acid-derived hormones

epinephrine, norepinephrine, thyroid hormones, dopamine, serotonin, melatonin

downregulation

Decrease in receptor number in response to high concentration of hormone

upregulation

increase in receptor number in response to low concentration of hormone

plasma concentration can be a ___ indicator of hormones activity

poor

direct gene activation

when a steroidal hormone binds to a specific receptor which then enters the nucleus, binds to part of the cell's DNA and activates a certain gene which activates mRNA which promotes protein synthesis

a non-steroid hormone molecule binds to a membrane receptor that triggers a series of reactions that lead to the formation of an intracellular ____ ____

second messenger

what are the functions of a second messenger

-carry out hormone effects

-intensify strength of hormone signal

prostaglandins

the "third class" of hormones that are derived from arachidonic acid and at as a local hormone (autocrine)

what are the major endocrine glands responsible for metabolic regulation

-anterior pituitary gland

-thyroid gland

-adrenal gland

-pancreas

the anterior pituitary releases hormones in response to the ______

hypothalamus

Growth hormone

a potent anabolic agent that promotes muscle growth and hypertrophy by facilitating amino acid transport into the cells

how does growth hormone impact metabolism?

by stimulating the liver to break down glycogen and by increasing the synthesis of lipolytic enzymes which directly stimulates fat metabolism... glucose sparing

what are the 2 hormones the thyroid gland releases?

triiodothyronin (T3) and thyroxine (T4)

T3 and T4 functions

-increase metabolic rates of all tissues

-increase protein synthesis

-increase size and number of most cells

-promote rapid cellular uptake of glucose

how is TSH impacted by exercise

once exercise begins, the anterior pituitary releases TSH which travels to the thyroid and stimulates T3 and T4 to be released

(in reference to thyroid)... during prolonged submaximal exercise _____. concentration increases sharply then remains relatively constant, while ______ concentrations tend to decrease over time

thyroxine, triiodothyronine

what are the hormones the adrenal medulla produce?

epinephrine and norepinephrine (catecholamines)

what are the 2 parts of the adrenal gland?

cortex and medulla

what is the percentage of epinephrine and norepinephrine release from the adrenal medulla

epinephrine: 80%

norepinephrine: 20%

what does the adrenal cortex release in response to exercise?

corticosteroids including Glucocorticoids, Mineralocorticoids and Gonadocorticoids

what is the major glucocorticoid released by the adrenal cortex in response to exercise

cortisol

what is cortisols function

-stimulates gluconeogenesis

-increase FFA mobilization, protein catabolism

-stimulates protein catabolism

incretin

a hormone produced by the intestine which increases insulin synthesis and release from the pancreas

insulin ____ Incretin levels?

decrease

how does insulin respond to hyperglycemia

by facilitating glucose transport into the cells and promoting glycogenesis and inhibiting gluconeogenesis

what are the 2 main hromones produced by the pancreas?

insulin and glucagon

glycogenolysis

breakdown of glycogen to glucose

Gluconeogenesis

formation of glucose from noncarbohydrate sources (FFA, protein)

what hormones increase circulating glucose

glucagon, epinephrine, norepinephrine, cortisol

how is cortisol utilized for glucose sparing during exercise?

by increasing protein catabolism, freeing amino acids which can be used for gluconeogenesis

how do catecholamines help spare glucose during exercise?

by increasing glycogenolysis

As exercise intensity increases, catecholamine release __, glycogenolysis rate __

increases, increases

as duration increases, ___ liver glycogen is used, ___ muscle glucose uptake, ___ liver glucose release. glycogen stores ___ and glucagon levels ____

more, increase, increase, decrease, increase

why does insulin levels decrease during exercise?

because exercise may enhance insulins binding receptors on the muscle fiber thereby reducing the need for high concentration for plasma insulin

why is FFA mobilization important during exercsie?

because when glycogen is depleted after endurance training, the body needs another source of glucose

lypolysis of triglycerides yields....

FFAs + glycerol

lipolysis is stimulated by

catecholamines, cortisol and GH

what cytokines/myokines do skeletal muscle fibers release

myostatin, interleukin, BDNF, Irisin, & Lactate

myostatin function

inhibits skeletal muscle growth

interleukins function

mediate inflammation, regulates metabolism and other cellular function

BDNF (brain derived neurotrophic factor) function

help improve neuroplasticity, grow the areas of the brain that are essential for learning and memory

irisin function

turns white fat into brown fat

what is the conversion of white fat to brown fat good?

because brown fat is more metabolically active which helps us increase our metabolic rate, keeps us cool

lactate function

can act as a signaling molecule. increases angiogensis growth and metabolism

angiogensis

formation of new blood vessels

glycogensis

formation of glycogen from glucose

what 2 hormones are released by the posterior pituitary and which one is important during exercise?

ADH and oxytocin, ADH

during exercise, plasma volume ____ which causes: a(n) ___ in hydrostatic pressure, ___ in plasma water content, ___ in heart strain, and ____ in BP

decreases, increase, decrease, increase, decrease

what hormones are responsible for correcting fluid imbalances

posterior pituitary gland, adrenal cortex, and kidneys

ADHs function

when blood osmolality increases it is released by the posterior pituitary and travels to the kidneys and promotes water retention in order to dilute the plasma

what major mineralocorticoid is released by the adrenal cortex in response to a decrease in blood plasma

aldosterone

mineralocorticoid

steroid hormone secreted by the adrenal cortex to regulate mineral salts and water balance in the body

what is the function of aldosterone

when plasma osmolality is high / low BP , aldosterone increases the number of sodium/potassium pumps and sodium pumps which helps reabsorb sodium which in turn brings in more water

difference between aldosterone and ADH

aldosterone is a mineralocorticoid which has an effect on minerals whereas ADH has an effect on water

explain the pathway of RAAS

1. prolonged exercise = low blood volume / hypohydration

2. kidneys sense dehydration from afferent tubules and release renin

3. renin is released into the blood and converts angiotensinogen into angiotensin 1 (Ang 1)

4. Ang 1 is going to contnue to circulate until i reaches the lungs where ACE converts it into Ang 2

5. Ang 2 stimultes the adrenal cortex to release aldosterone and vasoconstrict the blood vessels

6. Aldosterone acts on the kidneys to reabsorb sodium (and water)

what is the brains appetite control center?

hypothalamus

beta-cells

secrete insulin

cholecystoknin (CCK)

stimulated when the stomach is full

Glucagon-like peptide (GLP-1)

released in small intestine, decrease appetite

peptide YY (PYY)

released in small intestine, decrease appetite

ghrelin

increase appetite

the hormone leptin is primarily secreted by ____ ____ and acts on receptors in the hypothalamus to ____ hunger

fat cells, decrease

acute, vigorous exercise ____ PYY and GLP-1 and ____ ghrelin

increases, decreases

exercise training does not affect ghrelin accept in energy deficit (T/F)

true

the relation between testosterone concentration and hypertrophy is large (T/F)

false

GH and Testosterone are ____ during resistance trainig

elevated