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What are hormones?
Chemical messengers released in 1 tissue and transported by blood to target cells in other tissues
What are the 3 groups of hormones?
- Amino Acid Derivatives
- Peptide Hormones
- Lipid Derivatives
Amino Acid Derivatives are what?
Hormones that are structurally similar to amino acids ie epi, norepi, thyroid hormone & melatonin
Peptide hormones are?
- Consist of chains of Amino Acids
- Includes hormones secreted by hypothalmus, pituitary gland, heart, kidneys, thymus, digestive tract & pancreas
The 23 classes Lipid derivative hormones are?
- Steroid hormones
Steroid hormones are?
- Lipid derivative hormones that are derived fr cholesterol.
- Released by adrenal glands & reproductive organs
- Insoluable in H2O & bound to specific transport proteins
Eicosanoids are what and do what?
- Lipid derived hormones derived fr 20 carbon fatty acid arachidonic acid Coordinate local cellular activities & affect enzymatic processes in extracellular fluid
Name some similarities between the Nervous and Endocrine systems.
- Both rely on chemicals that bind to receptors on target cells
- Sharing of chemical receptors ie Epi & Norepi
- Regulation by negative feedback ctrl mechanisms
- Coordinate & regulate activities of other cells, tissues, organs & sys & maintain homeostasis
Hormone receptors are?
Receptors on a cell membrane or inside a cell that interact w/ given hormone
What is a G Protein?
- Links a 1st messenger to a 2nd messenger
- An enzyme complex that is coupled to a membrane receptor
- Its activated when a hormone binds to t receptor @ membrane surface
What is a first messenger & what does it trigger?
- Hormones binding to cell membrane receptors that do not have direct effects on the target cell.
- First messengers trigger Second messengers
What is a second messenger?
Molecules that reley signals fr receptors on cell surface to target molecules inside the cell
What is cyclic-AMP?
A hormone receptor complex is. . . . .
Freely circulating hormones are inactivated in three ways. They are?
- They diffuse out of bloodstream & bind to receptors on target cells
- They are absorbed & broken down by certain liver or kidney cells
- They are broken down by enzymes in plasma or interstitial fluid
What 2 hormones stay in circulation longer than most & why?
Steroid and thyroid hormones b/c almost all become attached to special transport proteins.
WHat provides the highest level of endocrine ctrl and why?
The hypothalmus b/c it acts as a link between the endocrine and nervous sys.
What are the 3 ways the hypothalmus regulates activities of the nervous & endocrine systems
- By secreting regulatory hormones
- By synthasizing ADH & oxytocin
- By ctrling endocrine cells of the adrenal medullae
What are regulatory hormones?
Hormones that ctrl activity of endocrine cells in the anterior pituitary gland
What are the 2 classes of regulatory hormones & what do they do?
- Releasing Hormones (RH)- stimulate production of 1 or more hormones in anterior pituitary gland
- Inhibiting Hormones (IH)- Prevent synthesis & secretion of pituitary hormones
The hypothalmus acts as an endocrine organ by secreting ____ & ____.
ADH & oxytocin
What are the 9 pituitary hormones?
- Thyroid stimulating hormone (TSH)
- Adrenocorticotropic hormone (ACTH)
- Follicle stimulating hormone (FSH)
- Luteinizing Hormone (LH)
- Prolactin (PRL)
- Growth Hormone (GH)
- Melancyte-Stimulating hormone (MSH)
What do portal systems do?
- Ensures that blood entering portal vessels reaches target cells b/f returning to general circulation
- They are named after their destinations
Thyroid stimulating hormone (TSH) targets the ____ & is released in response to ?
- Thyroid Gland
- Thyrotropin-releasing hormone(TRH) fr the hypothalmus
Adrenocorticoid Hormone (ACTH) stimulates the release of ____ hormones by the ____ ____.
- Steroid hormones
- Adrenal Cortex
ACTH release occurs under the stimulation of ____ -____ hormone fr the ____.
Gonadotropins regulate activities male & female sex organs. These are stimulated by ____-____ hormone from the ____.
What does follicle stimulating hormone (FSH) do?
- Females-promotes follicle & egg development & stimulates secretion of estrogens
- Males-supports sperm production in the testes
What does Luteinizing Hormone(LH) do?
- Females-Induces ovulation & secretion of estrogens & progestins
- Males-Stimulates interstitial cells of testes to produce androgens ie testosterone
Prolactin (PRL) works w/ other hormones to stimulate ____ ____ developement.
Growth Hormone (GH) aka ___ ___ hormone or ____ does what
- Human growth or somatropin
- Stimulates cell growth & replication by accelerating the rate of protein synthesis
Somatomedins or Insulin like growth factors (IGFs) are
Peptide hormones that bind t receptor sites on a variety of cell membranes
What regulates the production of GH?
- Growth Releasing Hormone (GH-RH) fr hypothalmus
- Growth Inhibiting Hormone (GH-IH) fr hypothalmus
Melanocyte Stimulating Hormone (MSH) stimulates ____to produce ____ but is not normally secreted by ____ human adults.
The post pituitary gland contains ____ fr 2 different grps of neurons located within the ____.
What triggers a response fr antidiuretic hormone (ADH)?
- rise in concentration of electrolytes in blood
- fall in blood vol or pressure
What is the primary function of ADH?
Decrease the amt of H2O lost in urine
How does ADH help increase BP?
By acting as a vasoconstrictor
What does oxytocin do for women?
Stimulates contractions in the wall of the uterus during labor & delivery & in contractile cells assoc w/ mammary glands
How many parathyroid glands are there & where are they located
- Posterior surface of the thyroid gland
The ____ ____ of the parathyroid produce parathyroid hormone (PTH) in response to what?
- Chief Cells
- Lower than normal concentrations of calcium ions
____ ____ & ____ of the thyroid gland maintain Ca ion levels within narrow limits
Chief Cells & C Cells
PTH also stimulates the kidneys to form & secrete ____, which promotes & secretes the absorption of Ca 2+ & PO4 3-byt the digestive tract
An ____ ____ lies along the superior border of each kidney & can be subdivided into the superficial ____ ____ & inner ____ ____.
- Adrenal Gland
- Adrenal Cortex
- Adrenal Medulla
What does the adrenal cortex produce & what are they called?
Produces > 2 doz steroid hormones called corticosteroids
What is one corticosteroid we use?
What are 3 regions of the adrenal cortex & what does each produce?
- Outer zone produces mineralocorticoids
- Middle zone produces glucocorticoids
- Inner zone produces androgens
What is Aldosterone & what does it do?
- Principal mineralocorticoid
- Stimulates conservation of Na+ & elimination of K- by targeting cells that regulate ionic composition of excreted fluids
What causes Aldosterone secretion?
- Drop in Blood Na content, blood vol or BP or a rise in blood K levels
- In response to angiotensin II
What are three most important glucocorticoids?
What are androgens & where are they produced?
- Sex hormones in Males
- Produced by the testes
The adrenal medulla has a ____ ____ coloration partly b/c of the many ____ ____ within it
- reddish brown
- blood vessels
The adrenal medulla contains 2 populations of secretory cells. One produces ____ & the other ____.
- Epi or adrenaline
- Norepi or noradrenaline
Where are receptors for epi & norepi found (4 places)
- Skeletal muscle fibers
- Liver Cells
- Cardiac Muscle fibers
The endocrine cells of the pancreas produce ____ & ____.
glucagon and insulin
Cells of the endocrine pancreas form clusters known as ____ ____ or ____ of ____.
- Pancreatic Islets
- Islets of Langerhans
Pancreatic Islets produce several cells types but 2 most important are ____ ____ that produce ____ & ____ ____ that produce ____
- Alpha Cells that produce glucagon
- Beta Cells that produce insulin
Normal Blood glucose or BG level is _____
Insulin lowers blood glucose by ?
Increasing rate of glucose uptake & utilization
Glucagon raises blood glucose by?
Increasing rates of glycogen breakdown & glucose synthesis in liver
Parasympathetic stimulation ____ insulin release where as sympathetic stimulation ____ it
Explain Glucose Sparing Effect
When glucose concentrations fall below normal homeostatic levels, insulin secretion is suppressed as is glucose transport into target cells. Cells now shift over to other energy sources such as fatty acids.
The kidneys release the steroid hormone ____, the peptide hormone ____ & the enzyme ____
Calcitriol is secreted by the kidneys in response to what?
Presence of parathyroid hormone
Erythropoietin (EPO) is released by the kidneys in response to what?
Low O2 levels in kidney tissue
EPO stimulates ?
Production of RBCs by bone marrow therefore elevating blood vol
Renin is released by specialized kidney cells in response too ____, ____ or ____.
- Decline in BP
- Decline in Blood vol
What is the renin-angiotensin sys?
When renin enters blood stream an enzymatic chain reaction begins leading to formation of angiotensin II which stimulates production of aldosterone
Where are endocrine cells of the heart located?
Wall of the R atrium
What does atrial natriuretic peptide (ANP) do?
- Opposes effects of angiotensin II
- Promotes loss of Na ions & H2O in kidneys
- Inhibits renin release & secretion of ADH & Aldosterone
What is the result of the secretion of ANP?
Lowers blood volume & BP
The thymus produces several hormones collectively known as ____.
Thymosins play a key role in the development & maintenance or ____ ____ ____.
Normal immune defenses
Adipose tissue produces 2 peptide hormones known as ____ & ____.
Leptin participates in. . . .
negative feedback ctrl of appetite
____ reduces insulin sensitivity throughout the body. It has been proposed as what?
- The missing link between obesity & Type II diabetes mellitus
When a cell receives instructions fr 2 different hormones @ the same time what 4 outcomes are possible
- Antagonistic Effects
- Synergistic Effects
- Permissive Effects
- Integrative Effects
When a cell receives instructions fr 2 different hormones & they have atagonistic effects what happens?
The 2 hormones oppose one another ie insulin & glucagon
When a cell receives instructions fr 2 different hormones & they have a synergistic effect this means . . . .
- the 2 hormones have additive effects where the net result is > the effect each would produce alone.
- ie glucose sparing action of GH & glucocorticoids
When a cell receives instructions fr 2 different hormones & the effect is permissive this means. . . . .
One hormone must be present if the 2nd hormone is to produce its effects
When a cell receives instructions fr 2 different hormones & integrative effects occur this means. . . .
That the 2 hormones produce different but complimentary results in a given tissue or organ
What are the 6 hormones that cooperate in order to produce normal growth?
- Growth Hormone (GH)
- Thyroid Hormone
- Parathyroid Hormone (PTH)
- Reproductive Hormones
Growth Hormone does what for normal growth?
- In children GH supports muscular & skeletal development
- In Adults GH helps maintain blood glucose & mobilize lipid reserves
Undersecretion of GH can lead to ____ ____.
Oversecretion of GH can lead to ____.
- Pituitary Dwarfism
Insulin effects normal growth by . . . .
allowing the passage of glucose & amino acids across cell membranes
Parathyroid Hormone & calcitriol effect normal growth by
promoting calcium absorption for building bones
Adrenocorticotropic Hormone (ACTH) stimulates the release of
steroid hormones by the adrenal glands
FSH production in males supports
maturation of sperm by stimulating sustentacular cells
The 2 hormones released by the posterior pituitary gland are
antidiuretic hormone & oxytocin
The hormone that induces ovulation in women & promotes ovarian secretion of progesterone is
The primary function of antidiuretic hormone (ADH) is to
decrease amt of H2O lost in the kidneys
The element required for normal thyroid function is
Reduced fluid losses in the urine due t retention of sodium ions & H2O is a result of the action of
The adrenal medullae produces the hormones
Epi and Norepi