Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
29 Cards in this Set
- Front
- Back
|
Hormones
|
-signaling molecules that are secreted directly into the bloodstream to travel to a distant target tissue -bind to receptors and induce a change in gene expression/cellular functioning |
|
|
Peptide Hormones
|
-made up of amino acids - derived from larger precursor polypeptides that are cleaved and then transported to the Golgi to be activated and directed to the correct location in the cell via exocytosis -charged & not plasma permeable -bind to extracellular receptors -considered the first messenger: binds to receptor and triggers transmission of a second signal (second messenger) - water soluble = can travel freely in bloodstream and do not require carriers |
|
|
Examples of Secondary messengers
|
-cyclic adenosine monophosphate (cAMP) - Inositol triphosphate (IP3) - calcium |
|
|
GPCR
|
1) peptide hormone binds extracellularly (activates GProtein) 2) GProtein binds/activates an effector (andeylate cyclase) 4) GProtein dephosphorylates and returns to GPCR 5) Effector produces a secondary messenger (andeylate cyclase converts ATP to cAMP) **6) cAMP activates protein kinase A **7) kinase A phosphorylates other proteins leading to a cellular response |
|
|
Steroid hormones
|
- derived from cholesterol - produced by gonads and adrenal cortex - permeable to cell membrane - receptors are intracellular/nuclear - binding causes conformational change - receptor can bind to DNA to increase or decrease transcription of genes - slower effects but longer lived than peptides - causes alteration in the amount of mRNA and protein present in a cell - nonpolar aka not water soluble, therefore they must be carried by proteins in the bloodstream to be able to travel around the body. |
|
|
Amino Acid Derivative Hormones
|
- derived from one or two amino acids with few modifications - Ex. epinephrine & norepinephrine (Bind to GPCR), triiodothyronine & thyroxine (Bind intracellularly) |
|
|
Direct Hormones |
-secreted and then act directly on a target tissue - ex. insulin released by pancreas causes increased uptake of glucose by muscles |
|
|
Tropic Hormone
|
- required intermediary to act -doesn't cause direct changes, but stimulates the production of another hormone - originate in the brain and anterior pituitary gland. - Gonadotropin- releasing hormone (GnRH) from the hypothalamus stimulates the luteinizing hormone (LH) and FSH. LH then acts on the gonads to stimulate testosterone and estrogen. |
|
|
Hypothalamus
|
- bridge between nervous and endocrine system - located in the forebrain above pituitary gland, below thalamus - lateral, ventromedial, and anterior - plays role in: emotional experience, aggressive/sexual behavior, metabolism, temperature reg, and water balance - controls pituitary gland through paracrine release - release of hormones regulated by negative feedback |
|
|
Hypophyseal portal system
|
-blood vessel system that directly connects the hypothalamus with the anterior pituitary - hormones are released from hypothalamus to the portal, down the pituitary stalk, and bind to receptors in the anterior pituitary to release other hormones. |
|
|
Hypothalamus Hormones
|
Hypothalamus --> Anterior Pituitary -->... -GnRH --> FSH and LH -Growth hormone- releasing hormone (GHRH) --> growth hormone (GH) -Thyroid releasing hormone (TRH) --> Thyroid stimulating hormone (TSH) - Corticotropin-releasing factor (CRF) --> Adrenocorticotropic hormone (ACTH) - Prolactin - inhibiting factor (PIF) = dopamine (causes a decrease in prolactin secretion) |
|
|
Hypothalamus and the posterior pituitary
|
- neurons in hypothalamus send axons down the pituitary stalk directly into the posterior pituitary to release oxytocin (stimulates contractions & milk letdown) and antidiuretic hormone/vasopressin (increases reabsorption of water into collecting ducts of the kidneys)
|
|
|
Anterior Pituitary
|
- synthesizes and secretes... Tropic - FSH and LH from GnRH (hypothalamus) to act on gonads - CRF (hypothalamus) --> ACTH --> adrenal cortex - TRH (hypothalamus) --> TSH --> Thyroid Direct -Prolactin: stimulates mile production in mammary glands (release of dopamine decreases secretion) - Endorphins: decrease perception of pain - Growth Hormone (GH): promotes growth of bone and tissue (prevents glucose uptake and stimulates breakdown of fatty acids) |
|
|
Bone Growth
|
- By GH - originates in epiphyseal plates - excess of GH = gigantism - Deficit of GH = dwarfism |
|
|
Posterior Pituitary
|
- contains nerve terminals of neurons from the hypothalamus -Receives and stores... -ADH (vasopressin): secreted in response to low blood volume or increased blood osmolarity - Oxytocin: secreted during child birth for contraction of the uterus or by suckling to promote milk ejection. Can be involved in bonding behavior. *Positive Feedback Loop* |
|
|
Thyroid
|
- sets basal metabolic rate and calcium homeostasis - located on the front surface of the trachea - controlled by TSH from ant. pit. - Releases... triiogothyonine (T3) and thyroxine (T4): produced by tyrosine in the follicular cells (resets metabolic rate by controlling energy production and utilizing glucose and fatty acids) Calcitonin: produced by C-cells: decreases plasma calcium levels by increasing Calcium excretion in the kidneys, decreased calcium absorption from the gut, and increased store of calcium in the bone. -Stimulated by high levels of calcium in the blood |
|
|
Parathyroid
|
- 4 small structures that sit on the side of the thyroid - Produces Parathyroid Hormone (PTH): raises blood calcium levels, and affects phosphorus homeostasis by resorbing phosphate from the bone and reducing reabsorption of phosphate in the kidney -Activates Vitamin D: calcitrol: to absorb calcium and phosphate in the gut |
|
|
Adrenal Cortex
|
- located on top of the kidneys - secretes corticosteroids (3 S's) |
|
|
Types of Corticosteroids
|
Glucocorticoids: Cortisol & Cortisone: regulate glucose levels, can decrease inflammation and immunologic responses - CRRF (hypoth.) --> ACTH (ant. pit.) --> glucocorticoids (Adrenal Cortex) Mineralocorticoids: Aldosterone: salt and water homeostasis (increases sodium reabsorption in the distal convoluted tubule and collecting duct of the nephron) - decreased BP --> kidney secretes renin --> angiotensinogen (inactive)--> angiotensinogen I--> Angiotensin converting enzyme ACE (in lungs) --> Angiotensin II --> adrenal cortex --> aldosterone Cortical Sex Hormones: Androgens & Estrogens: Play roles in physiological aspects |
|
|
Adrenal Medulla
|
- inside adrenal cortex - produces epinephrine and norepinephrine (catecholamine) to secrete directly into the circulatory system |
|
|
Pancreas
|
- produces digestive enzymes - endocrine and exocrine functions - contains islets of Langerhans that has alpha (glucagon), beta (insulin), and delta cells (somatostatin). |
|
|
Glucagon
|
- secreted by alpha cells in the pancreas due to fasting. - low glucose levels --> glucagon --> degration of protein/fat --> glycogen --> glucose & new glucose production via gluconeogenesis - inhibited by high glucose levels |
|
|
Insulin
|
- secreted by beta cells in the pancreas when blood glucose is high - induces muscle and liver cells to take up glucose and store it as glycogen for later use - stimulates anabolic processes like fat and protein synthesis -Excess = hypoglycemia - Underproduction = hyperglycemia = diabetes mellitus |
|
|
Types of Diabetes Mellitus
|
1: caused by autoimmune destruction of beta cells in the pancreas, requires regular insulin injections 2: result of receptor-level resistance to the effects of insulin |
|
|
Somatostatin
|
-Secreted by delta cells in the pancreas - inhibitor of glucagon and insulin - stimulated by high blood glucose and amino acid concentrations - can also be produced by hypothalamus to decrease GH |
|
|
Gonads
|
-Testes: secrete testosterone in response to stimulation by gonadotropins (LH and FSH) -Ovaries: secrete estrogen and progesterone in response to gonadotropins |
|
|
Pineal Gland
|
- located deep within the brian - Secretes melatonin which is involved in circadian rhythms. - receives projections from the retina to respond to decreasing light by secreting melatonin |
|
|
Kidneys
|
- water balance - produces erythropoietin: stimulates bone marrow to increase production of erythrocytes (RBC's) - secreted in response to low O2 levels in the blood |
|
|
Heart
|
-Releases trial natriuretic peptide (ANP) to regulate salt and water balance. -stimulates by stretched cells in the atria from excess blood volume |
