Term
| 3 major categories of Hormones (and 2 minor classifications) |
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Definition
-Peptide hormones (proteins of varying size)
-Amino acid-derivitive hormones
-Steroid hormones
(biologically-active lipids and glycoproteins) |
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Term
| What are the systems of action that hormones use? |
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Definition
-Endocrine: general release and action into circulation
-Paracrine: release and action nearby tissue
-Autocrine: release and action on same tissue |
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Term
| Hormone effect on a target tissue is _____ _______ to the _______ of the hormone AND the __________ contained in the tissue/cell |
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Definition
| directly related, concentration, receptor |
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Term
| What are the hormone effects on target tissues? |
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Definition
-Modify amount of intracellular protines
--gene expression or protein synthesis
-Change rate of enzymatic activity
-Alter membrane transport
-Induce secretory activity |
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Term
| Factors influencing homrone concentration: |
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Definition
-Rate of synthesis and/or secretioin from the endocrine gland
--pulsatile manner (diurinal)
-Rate of hormone metabolism/breakdown
-quantitiy of trnasport or binding proteins
-Plasma volume |
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Term
| Factors influencing synthesis and/ or secretion |
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Definition
| -hormonal, humoral, and neural |
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Term
| 2 Types of Hormone receptors: |
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Definition
1) INTRACELLULAR RECEPTORS
-Located: cytoplasm and/or nucleus
-H class: Steroid and thyroid H's
-Alter transcriptional activity of target genes
2)CELL SURFACE RECEPTORS
-Located: cell membrane
-H class: peptide hormones and catecholamines
-Generation of 2nd messengers which alter the activity of other molecules- usually enzymes w/in the cell |
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Term
| Steroid Hormone signaling facts |
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Definition
Steroid hormones are fat soluble
-carrier proteints are needed to transport steroid hormones in the blood
-steroid hormones are membrane permeable b/c they are fat soluble
--diffuse into cell and bind to intracellular receptors |
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Term
| Peptide hormone signaling facts |
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Definition
Peptide hormones are water soluble
-transported freely into blood
-sometimes bound to other proteins
Peptide hormones cannont enter cell b/c the membrane is made of lipids
-They bind to extracellular membrane receptor
-utilizes 2nd messenger system for inducing action |
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Term
| 3 major mechanistic categories |
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Definition
-substrate utilization
-tissue growth and repair
-fluid regulation |
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Term
| 3 major mechanistic categories |
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Definition
-substrate utilization
-tissue growth and repair
-fluid regulation |
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Term
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Definition
-at rest: fat is predominate fuel
-w/ exercise: increasting utilization of CHO as fuel
-Glucose sources: blood, glycogen (muscle & liver)
(glycogenolysis, gluconeogenesis --> glycolysis/TCA cycle/ ETC)
Lipid Sources: adipose tissue, IM triglycerides
(lipolysis --> FFA --> Beta-oxidation/TCA cycle/ETC |
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Term
| What hormones are responsible for eliciting substrate utilization responses to exercise? |
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Definition
| -insuline and Glucagon, cortisol, epinephrine, and GH |
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Term
| General effects of insulin and glucagon |
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Definition
INSULIN
-secreted by Beta cells of the pancreas
-in response to high plasma glucose concentrations
-responsible for the uptake and storage of glucose and ffa
-anabolic
GLUCAGON
-secreated by the Alpha cells of the pancreas
-in response to low plasma glucose concentrations
-responsible for the mobilization and availability of glucose and ffa
-catabolic |
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Term
| Insulin and Glucagon's mechanisms of action |
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Definition
INSULIN
-peptide hormone released from B cells
-binds to insulin receptor
--cell membrane receptor
--activates MULTIPLE 2nd messengers b/c insulin does more than just glucose uptake
GLUCAGON
-peptide hormone thats released from alpha cells
-binds to glucagon receptor
-cell membrane receptor (cyclic AMP)
-activates multiple 2nd messenger systems |
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Term
| What are the specific mechanisms of Insulin? |
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Definition
-Insulin primarily does UPTAKE and STORAGE and is stimulated by increase blood glucose
-Adipose tissue:
->stimulates FFA uptake
->Stimulates glucose uptake
->stimulates triglycerides synthesis (requires 3-C from glucose)
-Muscle & Liver
->stimulates glucose uptake
->stimulates glycogen synthesis via glycogen synthase. |
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Term
| Specific mechanisms of Glucagon |
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Definition
-Glucagon is primarily responsible for mobilization and is stimulated by decreased blood glucose.
-it renews glucose from nonglycolytic sources
-Adipose:
->stimulates lipolysis which is the release of triglycerides and glycerol
-Liver
->stimulates glycogenolysis (via glycogen phosphorylase)
->stimulates gluconeogenesis from AA and glycerol |
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Term
| What is Glucagon's specific mechanism in Muscle? |
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Definition
| -Glucagon doesn't work in muscle b/c there is no receptor for it. Skeletal M is not glucagon's target tissue. The muscle is greedy and won't release its glucose stores. |
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Term
| Explain the changes in glucose availability during exercise |
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Definition
-Blood glucose is maintained despite increased glucose uptake
-At higher intensity exercise, more glucose is needed. This is achieved via heptatic glucose production where glucose is released from liver
-this production of glucose causes an incresat in blood glucose concentrations.
-liver chills out on glucose synthesis causing uptake to exceed production. Body switches to utilizing lipids causing a drop in VO2
-exercise also stims epinephrine which stimulates liver to breakdown glycogen and release glucose.
-**epi inhibits the pancrease from releasing insulin during exercise because the body is fighting its natural response.
-Insulin stores glucose so by inhibiting it the body preserves glucose for exercising muscle. |
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Term
| Brief summary of glucose availability during exercise |
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Definition
-Blood glucose concentrations are maintained at lower intensities of exercise
-as exercise intensity increase, so does glucose uptake and utilization
-but blood glucose does not decrease, it increases via hepatic glucose production
-Epinephrine stimulates glycogenolysis and gluconeogenesis in the liver
-->epinephrine release from adrenal medulla via SNS stimulation (amino acid derivative hormone)
-Epinephrine inhibits the release of Insulin
--> insulin can't stimulate glucose uptake into other tissues
-->this preserves glucose for increasing muscle uptakte
increase Epi:
-Adipose tissue: TG-> FFA-> increase plasma FFA
-Liver:
Glycogen->glucose->maintains blood glucose |
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Term
| How does muscle uptake glucose with out insulin (as is the case with increase epinephrine concentration)? |
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Definition
-insulin independent mechanism!
-Exercise stimulates CaMK and AMPK
-CaMK and AMPK are active during high intensity exercise adn by pass insulin by inducing GLUT-4 uptake of glucose themselves.
-This form of glucose uptake is higher than insulin
-this is why exercise is the cure for diabetes. |
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Term
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Definition
"the stress hormone"
-main purpose is mobilization of substrate
-Muscle: promotes the breakdown of protein to AA
-Adipose: stimulates lipolysis and release of FFA
-Liver: stimulates gluconeogenesis from AA and glycerol
-Blocks glucose uptake into the tissues and preserves glucose for the brain and RBCs. |
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Term
| How is cortisol secretion controlled? |
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Definition
Cortisol is a steroid hormone that is controlled via a negative feedback system.
-it is synthesized in the adrenal cortex in response to stress
-The hypothalamus releases corticotropic-releaseing hormone (CRH) which stimulates the anterior pituitary gland to release Adrenocorticotropic hormone(ACTH) which stimulates the adrenal cortex to release cortisol |
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Term
| What are the metabolic effects of Growth Hormone? |
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Definition
catabolic in metabolism.
-Liver: stims gluconeogenesis
-adipose: breaks down TG into FFA and glycerol
-tissues: blocks glucose entry causing increase FFA oxidation |
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Term
| What are the metabolic pathologies associated with high levels of GH? |
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Definition
-Increased risk for cardiovascular disease
-->mobilization of FFA
-Increased incidence of sudden cardiac death
-->high FFA, low glucose causes cardiac arrhythemias
-Increased incidence of Type 2 diabetes
--> high glucose & inhibiiton of glucose uptake
-Abnormal lipid metabolism
->chronic FFA mobilization (tissues become desensitized to FFA) |
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Term
| Hormones responsible for tissue growth and repair |
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Definition
Androgens
-testosterone
-dihydrotestosterone
-androstenedione
Growth Hormone
-Insulin-like growth factors (IGFs) |
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Term
| Really cool facts about androgens |
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Definition
Androgens are steroid hormones
-cholesterol derivatives
-testosterone is most abundant in males
Produced in the testes
-secreted into the blood
-immediately bound to albumin or sex hormone-binding protein
-half-life: 30 min to several hours
Responsible for male features |
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Term
| What are testosterone effects on growth? |
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Definition
Testosterone increases muscle prtein synthesis
-activation of satellite cells => hypertrophy
-enhances neuromuscular junction size and activity
-->all of which contribute to increased force production
testosterone is converted to estrogen
-contributes to long bone growth
-mineralization of bones (stronger bones) |
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Term
| Describe Testosterone's response to exercise |
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Definition
A single bout of resistance exercise stimulates T production
-returns to baseline w/in hrs
-intensity-dependent (resistant)
-duration-dependent (aerobic)
Resistant training results in hight increaes in T product to single bout
Endurance trained athletes have lower testing T levels- 30-40% |
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Term
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Definition
GH is a peptide hormone
-binds to cell surface and activates 2nd messenger
-secreted from the pituitary gland
-in response to GH releasing hormone (GHRH) from the hypothalamus
GH causes growth in almost all tissues
Increases linear growth pattern
Gh Stimulates the deposition of protein
-cartilage and bone
->increases osteogenic cell division
->deposition of new bone
-->epiphyseal growth (growth plates on long bones)
-->mineralization of bone
GH stimulates the liver (and other tissues) to produce insulin-like growth factors (IGF)
-most growth effects are carried out by IGFs |
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Term
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Definition
GH secretion decreases about 50% after adolescence and drops to ~25% in the elderly
GH is released into the blood and taken up by tissues rapidly (20 min is half life)
-has to be made ahead of time
IGF is released slowly and half life is 20 hrs. |
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Term
| How is GH secretion controlled? |
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Definition
Negative feedback system
-GH or IGF inhibits the release of more GHRH
Stimulation:
-protein deficiency
-hypoglycemia/lipidemia
-exercise (duration/intensity-dependent)
-excitement/trauma
-sleep: 1st 2hrs of REM |
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Term
| What are the pathologies associated with GH? |
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Definition
1) Gigantism
-over production of GH (specifically IGF)
-Abnormally high linear growth
2)Dwarfism
-under production of GH
-stunted pre-pubescent growth (short long bones)
-2 types
--i) Anchondroplasia
---->bone growth defect prevents cartilage from being transform into bone
--ii) Short stature syndrom
----->pygmies of africa
----->GH levels normal but body can't synthesize IGFs
3)Acromegaly
-Overproduction of GH after adolescence
--stimulation of growth in facial bones, hands, and feet
--usually caused by pituitary gland tumor |
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Term
| What are the primary renal functions? |
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Definition
-Regulation of body fluid volume and electrolytes (osmolarity)
-Regulation of acid-base balance (pH)
-Excretion of natural wastes and foreign chemicals
-Regulation of arterial pressure
-secretion of hormones (Epo)
-Gluconeogenesis |
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Term
| What are the functions of the kidney? |
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Definition
kidneys filter ~ 180 L of plasma per day
Entire plasma volume is filtered 60x per day
-REtention of water and electrolytes
-excretion of waste.
-Tight control of plasma volume that helps maintain fluid balence. |
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Term
| Describe the structure of the kidneys |
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Definition
-Renal artery supplies blood to the kidney.
-Blood enters the kidney medulla.
-Functional unit of hte kidney is hte Nephron.
-Nephron is the site of filtration, reabsorption, excretion |
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Term
| Describe the nephron structure: |
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Definition
Nephron is composed of:
-Bowman's capsule which houses the glomerulus (site of filtration)
-Proximal tubule (colects the filtrate, primary site of reabsorption)
-Loop of Henle (site of reabsorption)
-Distal tubule
-Collecting duct (collects urine); drains to bladder |
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Term
| Renal blood flow during exercise |
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Definition
RBF decreases w/ higher intensity exercise
-Rest: 1300 ml/min; ~20% of cardiac output
-Max Ex: ~750 mL/min; 3-5% of cardiac output
-->sympathetic stimulation- vasoconstriction of arterioles |
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Term
| Describe the regulation of the flow of fluids |
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Definition
HYDROSTATIC PRESSURE
-The amount of pressure exerted by a fluid
-->plasma & interstitial fluid (extracellular) and intracellular
-Hydrostatic pressure is proportional to: volume of fluid, and area in which it's contained
OSMOLARITY
-The relationship b/t water and solutes in a solution
-concentration of solute per unit of fluid (moles of solute/liter of plasma)
OSMOTIC PRESSURE
-the pressure required to prevet the osmotic flow of fluid |
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Term
| Antidiuretic Hormone (ADH) |
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Definition
-Peptide hormoen
-target tissue is kidney
-funciton is reabsorption of water, concentration of urine
-more specifically, ADH stimulates cells in teh collecting duct to become more permeable to water and water reabsorption occurs
-Feedback mechanism: decreased plasma osmolarity = decrease ADH release |
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Term
| Describe IN DETAIL the renin angiotensin system |
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Definition
-Renin is secreted from the kidney in response to low blood pressure (decreased plasma volume)
-Renin release is proportional to exercise intensity
-Action of the renin_angiotensin system is to vasoconstrict arterioles and stimulate the release of Aldoesterone (a potent hormone that promotes the reabsorption of water and Na) |
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Term
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Definition
-Steroid hormone
-Produced by adrenal cortex in response to angiotensin II and decreased Na concentration
-stimulates water and na reabsorption in the distal tubule and water in the collecting duct.
-more specifically, aldosterone promotes gene expression of Na/K ion transporters in the distal tubuel
-as more Na is reabsorbed in the distal tubule more water can be reabsorbed from the collecting duct. |
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Term
| Water and electrolyte balance is restored by the integration of _________ ________ and ______ ____ |
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Definition
-Physiological reflexes (water loss & urinary excretion)
-Behavioral modifications (water intake & thirst) |
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Term
| Adrenocorticotropic Hormone (ACTH) |
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Definition
Gland: Ant pit gland
Stimulus: TRH, stress, injur, disease
Target tissue: adrenal cortex
effect: stims secretion of corticosteroids |
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Term
| Follicle Stimulating Hormone (FSH) |
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Definition
Gland: Ant Pit gland
Stim: GnRH (hypolthalamus)
Target tissue: Gonads (ovaries and testes)
Effect: Females-growth of ovarian follicles. Males- sperm production |
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