Chapter 4 Hormonal Control Flashcards
What are androgens ?
-Testosterone and its derivatives
-most common ergogenic aid used by female athletes
What are ergogenic effects ? (associated with steroid use)
Enhanced physical performance,stamina and recovery
What does the endocrine system refer to ?
Endocrine glands and their hormones
What do hormones regulate ?
- Metabolism, fluid / electrolytes, and calorie intake
What is the communication system of endocrine system ?
Endocrine system = Chemical communication
How does endocrine communication differ from nervous system ?
Slower responding and longer lasting
How does endocrine maintain homeostasis ?
-Through hormones
-Chemicals that control and regulate cell/organ activity
-Secreted in blood
-Act on target cells (has specific hormone receptors)
Is the endocrine system anatomically connected ?
No it is not.
An endocrine gland can only secrete one hormone.
False
What is the function of the endocrine system (expanded) ?
-Constantly monitors internal environment
-Coordinates integration of physiological systems during rest and exercise
-Maintains homeostasis during exercise
(controls substrate metabolism, regulates fluid/electrolyte balance)
How are hormones categorized as ?
Steroid and nonsteroid
What are steroid hormones derived from?
Cholesterol
What does lipid soluble mean ?
Diffuses through membranes
What are the major glands and the steroid they secrete ?
– Testes (testosterone)
– Ovaries (estrogen, progesterone)
– Adrenal cortex (cortisol, aldosterone)
– Placenta (estrogen, progesterone)
What are nonsteroid hormones made out of ?
-Protein/peptide hormones (most nonsteroid)
-Amino acid derived hormones
What are the important non steroids and their glands ?
Protein/Peptide
-From pancreas, hypothalamus, pituitary gland
(Insulin, glucagon, GHRH, GH, etc.)
*Most non steroid hormones
Amino Acid derived hormones
-Thyroid (T3, T4)
- Adrenal medulla
(epinephrine + norepinephrine = Catecholamine)
Can nonsteroid hormones cross membranes like steroid hormones ?
No they are not lipid soluble
How does it limit effects to specific targets?
By using hormone-specific receptors
What happens if you do not have the receptor?
No receptor = no hormone effect
What is Hormone bound to receptor called ?
hormone–
receptor complex
Where are receptor locations of steroids (lipid soluble) ?
receptors in cytoplasm or nucleus of target cell
(intracellular receptor)
Where are receptor locations of nonsteroids (nonlipid soluble) ?
receptors on membrane of target cell (cell membrane
receptor)
What happens when hormone receptor complex enters nucleus ?
– Binds to DNA and activates certain genes
– In response, mRNA synthesized within nucleus
– mRNA enters cytoplasm, promotes protein synthesis
What may the proteins be that the hormone receptor complex synthesizes ?
– enzymes
– structural proteins
– Regulatory protein that alters enzyme function
What happens when nonsteroid receptors land on cell membrane?
trigger release
of intracellular second messengers
What do the second messengers do ?
– Carry out hormone effects
– Intensify strength of hormone signal
What could the instensifying strength of hormones signals do ?
- Activation of cellular enzymes
- Change in membrane permeability
- Promotion of protein synthesis
- Change in cellular metabolism
What are common secondary messengers ?
– Cyclic adenosine monophosphate (cAMP)
– Cyclic guanine monophosphate (cGMP)
What does hypothalamus do in regard to the endocrine system ?
Stimulates release of hormones from
anterior pituitary gland
How does the hypothalamus stimulate release of hormones ?
By molecules known as releasing hormones or factors
How does the hypothalamus encourage release from posterior pituitary gland ?
Provided ADH
– Antidiuretic hormone (ADH)
What does Adrenocorticotropic hormone (ACTH) do ?
Stimulates cortisol release from adrenal glands
What does Luteinizing hormone (LH) do ?
Stimulates production of testosterone and estrogen
What does Thyroid-stimulating hormone (TSH) do ?
Controls thyroid hormone release from thyroid gland
What Major endocrine glands are responsible for
metabolic regulation ?
– Anterior pituitary gland
– Thyroid gland
– Adrenal gland
– Pancreas
What do the Major endocrine glands are responsible for
metabolic regulation do ?
Hormones released by these
glands affect metabolism of carbohydrate and fat
during exercise
What does the Anterior Pituitary Gland do ?
It secretes hormones in response to hypothalamic
hormone factors
What hormones does the Anterior Pituitary Gland do ?
– Includes both releasing factors and inhibiting factors.
– Exercise increases secretion of all anterior pituitary hormones.
What is one of the most important hormone secreted by the anterior pituitary gland ?
Growth Hormone
What are the effects of Growth Hormone ?
– Potent anabolic hormone
– Builds tissues, organs (Amino acid uptake and
protein synthesis)
– Long bone growth
– Promotes muscle growth (hypertrophy)
– Stimulates fat metabolism (spares plasma glucose)
What does GH released during aerobic and resistance
exercise result in ?
– proportional to exercise intensity
– remain elevated after exercise
What does the thyroid secrete ?
Secretes triiodothyronine (T3)
and thyroxine (T4)
What happens when T3 and T4 increases ?
– metabolic rate of all tissues (influences RMR-resting metabolic rate)
– protein synthesis
– number and size of mitochondria - increase aerobic metabolism = Increase ATP
– glucose uptake by cells
– rate of glycolysis & gluconeogenesis
– FFA mobilization
Where are the adrenal glands?
Above each kidney
What are the 2 parts of the adrenal glands ?
The adrenal cortex and adrenal medulla
When stimulated by sympathetic nervous system what does the adrenal medulla release ?
catecholamines
What do catecholamines do ?
– Causes “fight-or-flight” response
– Epinephrine 80%, norepinephrine 20% - increase Exercise = increase sympathetic nervous system= increase
epinephrine and norepinephrine
What does catecholamines release increase in body functions ?
– Heart rate, contractile force, blood pressure
– Glycogenolysis
– Lipolysis
– Blood flow to skeletal muscle
What is the important hormone of adrenal cortex ?
cortisol (hydrocortisone)
What does cortisol (hydrocortisone) do on release ?
– increase gluconeogenesis for fuel
– increase FFA mobilization
– protein catabolism for repair, enzyme production, gluconeogenesis
– Acts as an anti-inflammatory, depresses anti-immune reactions.
What are the 2 major hormones of pancreas ?
Insulin and Glucagon
What does the pancreas do during hyperglycemia (e.g., after a meal) ?
the pancreas releases insulin
What is the main function of insulin ?
lowers [blood glucose]
– counters hyperglycemia
– increases glucose transport into cells (especially muscle)
– increases glycogenesis (making glycogen)
– inhibits gluconeogenesis (stops making glucose)
What does the pancreas do during hypoglycemia ?
the pancreas releases glucagon
What is the main function of glucagon ?
increase [blood glucose]
– counters hypoglycemia
– increases glycogenolysis (liver glycogen to glucose)
– gluconeogenesis
What happens to carbohydrate metabolism regulation during exercise ?
During exercise…
* ↑Glycogenolysis (glycogen=glucose)
* ↑Gluconeogenesis (FFA, protein=glucose)
What hormones regulate metabolism ?
-Growth hormone (anterior pituitary)
-T3/T4 (Thyroid)
-catecholamines (adrenal medulla)
-Cortisol (Adrenal cortex)
-Insulin (Pancreas)
-Glucagon (Pancreas)
What do the hormones that regulate metabolism specifically do
-GH = Stimulates fat metabolism (spares plasma glucose)
What does adequate plasma glucose require a balance of during exercise?
– Glucose release by liver
– Glucose uptake by muscles
What hormones help circulate glucose during exercise ?
– Glucagon
– Epinephrine }INCREASE glycogenolysis
– Norepinephrine
– Glucagon/Cortisol=protein catabolism=
INCREASE in gluconeogenesis
What happens to regulation of carbohydrate metabolism as exercise intensity increases ?
– catecholamine release INCREASES
– glycogenolysis rate INCREASES (liver, muscles)
– muscle glycogen is used before liver glycogen
What happens to regulation of carbohydrate metabolism as exercise duration increases ?
– more liver glycogen is used;
– INCREASE in muscle glucose uptake= INCREASE in liver glucose release
– as glycogen stores DECREASE glucagon levels INCREASE
Insulin: enables glucose uptake in muscle
True
What happens during exercise when insulin concentrations DECREASE ?
Due to INCREASE in insulin sensitivity during exercise more glucose uptake into cells with less insulin.
During endurance exercise how is fat metabolism regulated ?
- FFA mobilization and fat metabolism: critical to endurance exercise
– Glycogen depleted, fat energy substrates needed
– In response, fat breakdown (lipolysis) accelerated
What do Triglycerides equal ?
FFA and glycerol
– Fat stored as triglycerides in adipose tissue
– Broken down into FFAs, transported to muscle
– Rate of triglyceride breakdown into FFAs: possible determinant of rate of cellular fat metabolism
How is lipolysis stimulated ?
– (decreased) insulin,
– epinephrine,
– norepinephrine,
– cortisol
– GH
*They stimulate lipolysis via lipase.
GH:____ FFA Mobilization & ____ Cellular Glucose uptake.
Increases, Decreases
T3,T4:____ glucose catabolism and fat metabolism
Increases
What are the effects Hormonal Regulation of Fluid and Electrolytes during exercise ?
– Water shifts from plasma volume to
interstitial and intracellular spaces
– Sweating increases during exercise
What happens to plasma volume during exercise ?
- DECREASE of plasma volume during exercise
– Prolonged running can decrease PV
by 5 – 10%
What are the effects of plasma volume decreasing during exercise ?
- Blood pressure DECREASES
-Heart Strain INCREASES
*This impedes exercise performance
What glands are involved in monitoring fluid levels and electrolyte balance ?
– Posterior pituitary gland (ADH)
– Adrenal cortex (Aldosterone)
– Kidneys (not only a target organ; also a gland) (EPO)
What does the posterior pituitary gland secrete ?
antidiuretic hormone
(also called ADH or vasopressin), oxytocin
*Produced in hypothalamus ut stored there
Where does the ADH increase water reabsorption ?
Kidneys
What is the point of the ADH?
Minimizes water loss and severe dehydration
What does the adrenal cortex secrete besides cortisol ?
Aldosterone
How does Aldosterone contribute to Hormonal Regulation of Fluid and
Electrolytes ?
Increases sodium (Na+) retention by kidneys which leads to water retention via osmosis
What does EPO (erythropoietin) do ?
– Released in response to low blood O2 in kidneys.
– Stimulates red blood cell production.
– Is critical for adapting to training, altitude.
How are the kidneys involved in Hormonal Regulation of Fluid
and Electrolytes ?
– release erythropoietin (EPO) that targets bone
marrow to stimulate red blood cell (RBC) production
– are target tissue for ADH & aldosterone
– Can stimulate: renin-angiotensin-aldosterone mechanism
What is the goal of the Renin-Angiotensin-Aldosterone Mechanism ?
To release aldosterone which: increases Na+ retention by kidneys which increases water retention via osmosis
What triggers the Renin-Angiotensin-Aldosterone Mechanism ?
- Kidneys sense decrease in blood volume and decrease in BP
*It then releases enzyme called renin into circulation
What happens in the RAA mechanism after renin is releases into circulation ?
- In circulation renin converts angiotensinogen molecule into angiotensin I
- In the lungs, angiotensin-converting enzyme (ACE): converts angiotensin I into angiotensin II
- Angiotensin II reaches adrenal cortex and stimulates aldosterone
How is the GI tract involved in Hormonal Regulation of Calorie Intake?
releases hormones that affect
hunger signals
What hormones regulators are released in GI tract for calorie intake ?
– Cholecystokinin (CCK)
– Glucagon-like peptide 1 (GLP-1)
– Peptide YY (PYY)
– Ghrelin
Cholecystokinin (CCK)
Is stimulated when stomach
is full; decreases appetite.
Glucagon-like peptide 1 (GLP-1) & Peptide YY (PYY)
Is released in
small intestine; decreases appetite
Ghrelin
Increases appetite
Adipose is an endocrine organ what does it release ?
Leptin is released from adipose stores and reduces hunger
If obese people have higher leptin why do they not have decreased hunger ?
They are resistant
What happens to Hormonal Regulation
of Calorie Intake during acute exercise ?
Moderate to vigorous aerobic exercise leads to DECREASE in ghrelin temporarily reduces hunger
What happens to Hormonal Regulation
of Calorie Intake during chronic exercise ?
- Does not change ghrelin response in people who do not lose weight during exercise training
- Ghrelin increases in those who do lose weight
