Endocrine Test 5 Physio

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What is the function of Endocrine Glands?
Secrete their products (hormones) into the bloodstream
Endocrine Hormones are surrounded by?
Rich capillary network which is where their products enter to then be put into general circulation which means endocrine hormones have far reaching effects
What is epinephrine better classified as?
Endocrine Hormone because its released from adrenal glands
How do hormones act?
Through receptors and what dictates wether it will affect a different organ or a different site is wether that organ or site has the receptor or not
Organs and sites might have different receptors for multiple hormones T/F?
TRUE
What are some actions of hormones?
-Metabolism
-Growth Production
-Reproduction
What is the structural classification of hormones?
-Amines
-Polypeptides and proteins
-Glycoproteins
-Steroids
What are amines hormones?
-Amino Acid derivatives
Examples:
-Epinephrine
-Norepinephrine
-Dopamine
All are derivatives of tyrosine
What are Polypeptides and proteins hormones?
-8 Amino acids or more
Examples:
-ADH
-Insulin
What are glycoproteins hormones?
-Protein with a carbohydrate component (Sugar)
Ex: FSH, LH
What are steroid hormones?
-Derivatives of cholesterol
Examples:
-Testosterone (Males)
-Estrogen (Females)
-Progesterone (Females)
-Cortisol
-Corticosterone
-Aldosterone
What are the two categories of hormones?
-Lipophilic Hormones (Lipid/Fat Soluble)
-Hydrophilic Hormones (Water Soluble)
Where are the receptors for a lipophilic hormone?
-Since they can diffuse through the cell membrane their receptors are found inside of the cell
Examples:
-Steroid hormones
-Thyroid Hormones
-Need Carrier proteins to transport through the blood
Where are the receptors for a hydrophilic hormone?
-Since they are water soluble and they can't diffuse through the cell membrane their receptors are found on the cells surface
-Receptors are coupled to G-proteins or second messenger systems
-No problem transporting through the blood
Example:
-Catecholamines
-Peptides
-Glycoproteins (FSH, LH)
Many hormones are produced as inactive precursors that will cleave to make active hormones T/F?
True
What is a prepro-hormone?
-Inactive precursor of a pro-hormone
-Biggest and longest
-When it cleaves off a signal peptide, it becomes a pro-hormone
What is a pro-hormone?
-Inactive precursor of insulin
-When it cleaves off a C-chain (C-peptide), it becomes insulin the active hormone
Antagonistic Effects
-Action of one opposes effects of another
Example:
-Insulin lowers blood sugar levels
-Glucagon raises blood sugar levels
Synergistic Effects
-Two or more hormones work together to evoke a larger effect
-One action is greater than additive
Example:
-2 hormones will increase heart rate on their own, together the effect is greater
Permissive Effects
-One hormones make a target cell respond better to a second hormone
-One hormone enhances responsiveness of a target organ or increases the activity of a second hormone
Example:
-Estrogen permissive to progesterone
-Exposure of uterus to estrogen causes up regulation (increase # of receptors) of progesterone receptors which causes a bigger effect than progesterone just being released alone
What is action of lipophilic hormones? (Lipid Soluble, Steroid and thyroid Hormones)
-They are transcription factors
-Activate gene transcription
What is action of hydrophilic hormones? (Water Soluble Hormones)
-They are bound to second messenger systems
What is a gene?
Portion of DNA that coats for a protein
What is transcription?
Process of making a messenger RNA which is a copy of genetic information, the instructions to make a protein that will go to the ribosomes
How do steroid hormones activate gene transcription?
-Steroid hormone causes genes to be turned on and make the proteins that they make be synthesize
-Needs a regulator protein
What does Aldosterone do?
-Steroid hormone that activates gene transcription
-Sodium reabsorption at the expense of potassium
-Retains salt and water and excretes potassium
-Causes production of sodium potassium ATPase pump
What is hormone responsive genes?
-Receptors are ligand gated activated transcription factors that turn on hormone responsive genes
-When a steroid hormone binds to its receptor it causes gene transcription to be activated which causes the formation of proteins that the receptor is turning on
What are the two hormones of the thyroid gland?
-T3 (active form) and T4 (has to be converted to T3 to be activated)
-Travel via carrier proteins
-Act just like steroid hormones
-They bind to receptors in the nucleus and activate gene transcription
-Need iodine to synthesize thyroid hormone
What are the 3 systems for water soluble hormones?
-Adenyl Cyclase System
-PLC (Phospholipase C)
-Receptor Tyrosine Kinases
Adenyl Cyclase System
-Mechanism of epinephrine, norepinephrine, and Beta adrenergic receptors
-Hormone is a ligand and binds to a G-protein coupled receptor which causes the dissociation and activation of G-Protein
-G-Protein activates enzyme adenylate cyclase to make cAMP (increases heart rate)
-cAMP activates cAMP dependent protein kinase that is a trigger for the activation of many cellular processes
PLC Phospholipase C
-Hormone binds to a G-protein receptor
-Which causes the G-protein to split and activate enzyme phospholipase C
-Enzyme cleaves a membrane lipid to make IP3
-IP3 causes a release of intracellular Calcium from the endoplasmic reticulum
Receptor Tyrosine Kinases
-Insulin receptor, GF receptor, IGF receptor work this way
-Hormone binds to a receptor with intrinsic tyrosine kinase activity
-Receptors bind and phosphorylate (add a phosphate group) to each other to become activated
-This attracts other proteins to the scene
-Proteins get phosphorylated by receptor and become active
-Proteins finally carry out the effects of the hormone
What are the hormones of the anterior pituitary?
-Growth Hormone GH
-Thyroid Stimulating Hormone TSH
-Adrenocorticotrophic Hormone ACTH
-Follicle Stimulating Hormone FSH
-Leutinizing Hormone LH
-Prolactin Hormone PRL
What are the hormones that the posterior pituitary stores?
-Anti-deuretic Hormone ADH
-Oxytocin
What is the regulation of posterior pituitary hormones?
-Produced in the hypothalamus
-Travel along axons of hypothalamohypophyseal tract to the posterior pituitary where they get stored and released
-Controlled by neuroendocrine reflexes which are nerve impulses in hypothalamus that cause release from pituitary
Where are the posterior pituitary hormones produced?
Hypothalamus
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