Test 6 Endo Hormones Slides 1-46 Flashcards
What are the Mediator Molecules used by the Nervous System and by the Endocrine System?
- Nervous: Neurotransmitters
- Endocrine: Hormones
What are the Sites of Action for the Nervous System and Endocrine System?
- Nervous: Synapse, Close to site of release
- Endocrine: Far from site
What are the Type of Target Cells for the Nervous System and Endocrine System?
- Nervous: Muscle cells, gland cells, neurons
- Endocrine: Cells throughout the body
What are the times of Onset of Action for the Nervous system and Endocrine system?
Nervous: milliseconds
Endocrine: Sec- hrs- days
What is the duration of action for the nervous system and endocrine system?
Nervous: Brief milsec-sec
Endocrine: sec-days
What mediator molecules serve as both Neurotransmitter and a hormone?
Norepinephrine
Epinephrine
Oxytocin
Name the Endocrine Glands, Organs, and Tissues?
Hypothalamus Pituitary Gland Pineal Gland Thyroid Gland Parathyroid Gland Thymus Adrenal Gland Pancreas Testes Ovaries -Skin, Heart, Kidneys, Stomach, Small Intestine, Placenta, Adipose Tissue
What are the characteristics of Hormone Receptors?
- They are Cellular Proteins
- Synthesized and broken down (2K-100K)
- Located: cell surface and/or inside the cell
What is Receptor Down-Regulation?
- Occurs when too much hormone present
- Reduce receptors to decrease sensitivity
What is Receptor Up-Regulation?
- Occurs When too little hormone present
- Increase receptors to increase sensitivity
What chemical class of hormone is unable to travel unbound in blood and must be attached to transport protein, passes through cell membrane and finds receptors inside the cell?
Lipid-soluble (lipophilic)Hormones
What chemical class of hormone travels unbound in blood, unable to pass through cell membrane, and attaches to receptros outside the cell?
Water-soluble (hydrophilic) Hormones
What types of hormones are lipophilic?
- Steroid Hormones
- Thyroid Hormones (T3/T4)
- Nitric Oxide
What types of hormones are hydrophilic?
- Amine Hormones
- Peptide/Protein Hormones
- Eicosanoid Hormones
What water-soluble hormones are derived from arachidonic acid (20-C fatty acid) (Prostaglandins, Leukotrienes), and are mostly local hormones but can be circulating?
Eicosanoid Hormones
What is Permissive Effect?
Action of one hormone on target cell requires a recent or simultaneous exposure to a second hormone
What hormone interaction is concentration based; cannot exert its full effect w/out the presence of another hormone? (Alone=weak=not full effect)
Permissive Effect
Second hormone has permissive effect on first hormone
What is Antagonistic Effect?
One hormone opposes the action(s) of another hormone
What is Synergistic Effect?
Effect of two or more hormones acting together is greater than the effect of each hormone acting alone
What hormone interaction has full effect but limited, however effect is greater when combined with synergistic hormone(s) than if it were alone?
Synergistic Effect
A circulating hormone is one that…?
Is passed from secretory cells to the interstitial fluid into the blood stream
-Majority of hormones are circulating
A local hormone is one that…?
Acts on neighboring cells or the same cell without entering the blood stream
What are Paracrines?
Hormones that act on neighboring cells
What are Autocrines?
Hormones that act on same cell
What lipid-soluble hormones are derived from cholesterol and contain a four-ring structure?
Steroid Hormones
Name the site of Secretion for the following Lipid-Soluble Hormones, Aldosterone, Cortisol, Androgens, Calcitriol, Testosterone, Estrogen, Progesterone?
- Aldosterone: Adrenal Cortex
- Cortisol: Adrenal Cortex
- Androgens: Adrenal Cortex
- Calcitriol: Kidneys
- Testosterone: Testes
- Estrogen: Ovaries
- Progesterone: Ovaries
What enhances the lipid solubility of T3 and T4 Thyroid Hormones?
Iodination of tyrosine
Tyrosine is lipid-soluble and attachment of iodine during synthesis increases this
What effects does Nitric Oxide have as a hormone?
- Regulate hormone release in hypothalamopituitary axis (multiple action)
- Inhibit Prolactin Secretion
What effects does Nitric Oxide have as a neurotransmitter and where is it released from?
Vasodilation (Major Role)
Released: Brain, Spinal Cord, Adrenal Glands, and Most Nerves
The Amine Hormones, which are water-soluble hormones, are synthesized how?
-Decarboxylating (removing CO2 and/or modifying AA)
Maintains Amine group (NH3)
What is the site of secretion for the following Amine water-soluble hormones, Epinephrine, Norepinephrine, Dopamine, Melatonin, Histamine, Serotonin?
- Epi: Adrenal Medulla
- NorEpi: Adrenal Medulla
- Dopamine: Adrenal Medulla
- Melatonin: Pineal Gland
- Histamine: Mast Cells/Platelets
- Serotonin: Platelets
Hypothalamus is the site of secretion for which water soluble Peptide/Protein Hormones?
- Growth Hormone Releasing Hormone (GHRH)
- Growth Hormone Inhibiting Hormone (GHIH) (Somatostatin)
- Prolactin Releasing Hormone (PRH)
- Prolactin Inhibiting Hormone (PIH)
- Corticotropin Releasing Hormone (CRH)
- Thyroid Releasing Hormone (TRH)
- Gonadotropin Releasing Hormone (GnRH)
Posterior Pituitary is the site of secretion for which water soluble Peptide/Protein Hormones?
Oxytocin Antidiuretic Hormone (ADH)
Anterior Pituitary is the site of secretion for which water soluble Peptide/Protein Hormones?
- Human Growth Hormone (HGH)
- Adrenocorticotropin Hormone (ACTH)
- Prolactin
- Luteinizing Hormone (LH)
- Follicle Stimulating Hormone (FSH)
- Thyroid Stimulating Hormone (TSH)
- Melanocyte Stimulating Hormone (MSH)
Pancreas is the site of secretion for which water soluble Peptide/Protein Hormones?
- Insulin
- Glucagon
- Somatostain (Growth Hormone Inhibiting Hormone, GHIH)
- Pancreatic Polypeptide
Parathyroid Glands are the site of secretion for which water soluble Peptide/Protein Hormones?
Parathyroid Hormone
Thyroid Gland (sp. parafollicular cells) is the site of secretion for which water soluble Peptide/Protein Hormones?
Calcitonin
Stomach and Small Intestine are the site of secretion for which water soluble Peptide/Protein Hormones?
- Gastrin
- Secretin
- Cholecystokinin
- Glucose-dependent Insulinotropic Peptide (GIP)
Kidneys are the site of secretion for which water soluble Peptide/Protein Hormones?
Erythropoietin
Adipose Tissue is the site of secretion for which water soluble Peptide/Protein Hormones?
Leptin
The Eicosanoid water-soluble hormones are derived from what and mostly have what effect?
Derived: Arachidonic acid (20-C fatty acid)
Effect: Mostly local but can be circulating
What are the Eicosanoid water-soluble hormones?
Prostaglandins
Leukotrienes
Lipid-soluble hormones typically require what so they can be transported through the body?
Transport Proteins (Synthesized in Liver)
Which type of hormone is able to be transported in the blood in an unbound (free) form?
Water-Soluble
The Amine water-soluble hormones, Epinephrine, Norepinephrine, and Dopamine are synthesized by modifying/decarboxylating what AA?
Tyrosine
The Amine water-soluble hormone Melatonin is synthesized by modifying/decarboxylating what AA?
Tryptophan
The Amine water-soluble hormone Histamine is synthesized by modifying/decarboxylating what AA?
Histidine
The Amine water-soluble hormone Serotonin is synthesized by modifying/decarboxylating what AA?
Tryptophan
What are the steps in the Mechanism of Action for a Lipid-Soluble Hormone?
1) Diffuses from blood to interstitial fluid to lipid bilayer (most cases)
2) Binds and activates receptors in cytosol or nucleus, altering gene expression
3) Transcription leads to new mRNA which leaves the nucleus and enters the cytosol
4) New mRNA directs synthesis of new proteins (often an enzyme)
5) New protein alters Cell’s Activity (Response to hormone)
What is significant about Water-Soluble Hormones interaction with the plasma membrane of a cell?
- Cannot diffuse across the membrane.
- Bind to transmembrane receptors on cell surface
When a hormone binds to a cell-surface receptor and initiates intracellular activity, the hormone is a?
First Messenger
The signal received from the cells surface via a first messenger triggers an action that produces cellular response via what?
Second Messenger
The Second Messengers are considered to be what, since they mediate a hormone’s action?
Intracellular Mediators
What makes a hormone’s action adequate even when plasma concentrations are low?
Effect of a single hormone molecule is amplified via a cascade effect inside the cell in which each step amplifies the initial effect
What is the difference between Synergistic Effect and permissive Effect?
Synergistic: Two or more hormones produce same effects in a target cell and their effect are amplified when combined.
Permissive: Hormone cannot exert its full effects without the presence of another hormone.
