Chapter 18 - The Endocrine System Flashcards
Endocrine: Secrets hormones into …
interstitial fluid —> blood
Exocrine: Secrets products into …
ducts that carry product into body cavity
Upregualtion
target cell receptors INCREASE, making the target cell MORE sensitive to a hormone
ex. Increased oxytocin levels during labor
Downregulation
target cell receptors DECREASE, making the target cell LESS sensitive to a hormone
ex. insulin receptors downregualte in type II diabetes
Local Hormone types
Autocrine and Paracrine
Circulating Hormone types
Neurocrine and Endocrine
Paracrine acts on…
Nearby target cells
Autocrine acts on…
Its own cell
Neurocrine
Hormone released by “neurosecretory” cell
ex. antidiuretic hormone (hypothalamus and posterior pituitary)
Endocrine
Hormone released by secretory cells
ex. adrenocorocpropin (most endocrine organs)
Lipid-Soluable hormones
Steroid hormones (Cortisol), Thyroid hormones (T3, T4), Nitric Oxide
Water-Soluable hormones
Amine hormones (epinephrine), Peptide and Protein Hormones (Anti-diuretic hormone), Eicosanoids (prostaglandin)
Hydophobic vs Hydophillic messengers …
Hydophobic are secreted by diffusion and are bound to carrier proteins in blood stream; Hydrophillic are secreted by exocytosis and are dissolved in blood stream
Lipid-Soluable hormones…
1) Hormone binds to receptor 2) hormone- receptro complex binds to DNA 3) Hormone-receptor complex acts as a transcription factor 4) up/down regualtes genes 5) change in gene expression alters cell structure and function
Water-Soluable hormones
1) Hormone (first messenger) binds to membrane bound receptor 2) Hormone binding activates second messenger inside the cell 3) Second messenger activates protein kinase 4) Protein kinases phosphorylate cellular proteins
5) Phosphorylated proteins cause reactions which produce physiological responses
Action of Hormone
Antagonistic effect (is opposed by another hormone) Permissive Effect (Requires simultaneous or recent exposure to second hormone) Synergistic effect (is greater or more extensive when acting with a second hormone)
The hypothalamus controles…
Autonomic nervous system, Hormone production, body temp, emotion/behaviour, Eating/Drinking, Circadian Rhythm and Consciousness
Anterior Pituitary secrets which hormones…
Human growth hormone
hGH is controlled by which hormones? What is its Function?
Growth hormone - releasing hormone (GHRH)
Growth hormone - inhibiting hormone (GHIH)
Human growth hormone Elicits secretion and release of insulin-like growth factors (IGF)
Insulin like growth factors (IGF) are released by…
Skeletal muscles, bone, cartilage, live, other tissues
function: growth and maintenance , glucose metabolism (negative feedback)
Thyroid- stimulating hormone (TSH) - Anterior pituitary
Releasing hormone: Thrytropin-releasing hormone (TRH)
Inhibiting hormone:
Growth hormone-inhibiting hormone (GHIH)
Function: Stimulates synthesis of thyroid hormones (T3 & T4)
Adrenocorticotropic hormone (AC) - Anterior Pituitary
released by: corticotropin-releasing hormone (CRH)
Function: Stimulates secretion of glucocorticoids and andorgens by adrenal cortex
Melanocyte-stimulating hormone (MSH) - Anterior pituitary
Released by: corticotropin-releasing hormone (CRH)
Inhibited by: Prolactin - inhibiting hormone (PIH) aka dopamine
Function: Influences brain activity, darkens skin
Antidiuretic hormone (ADH) - Posterior Pituitary
Function: Decreases urine production, Increase water retention, increase blood pressure
Synthesis and secretion of T3 and T4
- Thyroid follicular cells trap iodide ions
- Thyroid follicular cells synthesis TGB (Thyroglobulin)
- TGB released into the Lumen of the follicular cell
- Iodide is oxidized to iodine
- Iodine + TGB on tyrosine protein
- This collision forms, Colloid, stick material
- T1 and T2 are formed
- Coupling of T1 and T2 forms T3 and T4
- diffuse into blood
- Traveling in blood bound to thyroxinebinding globulin (TBG)
Calcitonin
jh
Parathyroid hormone (PTH)
lkj
Calcitriol
lkj
Synthesis of mineralocorticoid - aldosterone
lkj
Glucocorticoids
zona fasciculata
- Cortisol
- Corticosterone
- Cortisone
Androgens
Zona recticularis
- Dehydroepiandrosteorne (DHEA)
- precursor to sex hormones
Mineralcorticoid (mainly aldosterone)
Zona glomularis
Adrenal medulla makes…
Epinephrine (80%)
norepinephrine (20%)
Pineal Gland
Composed of Neurolia and pinealocytes
- secretes melatonin
- controlled by suprachiasmatic nucleus
- function: sets biological clock
stress response
- stimulus
- sympathetic
- short response (fight or flight)
- resistance reaction (CRH, GHRH, TRH are released to help body continue fighting the stressor)
- exhaustion
Fight or Flight Response
Increases sympathetic nervous system activity to…
- Effector organ (heart, blood vessels)
- Adrenal Medulla (hormone release – lasts 5-10 times longer than nueral stimulation)
Resistance reaction
Hormone release by hypothalamus - longer Lasting response
- Cortisol, Aldosterone, T3, T4, Adipocytes
Exhaustion
Depletion of resources
- muscles wasting
- immune suppression
- beta cell failure
Aging Endocrine system
Reductions
hGH -- muscles atrophy T3, T4 -- Decreased metabolic rate, increase body fat Calcitonin -- Osteoporosis Corisol, Aldosterone -- decrease Insulin release -- decreases
Aging Endocrine System (Increases)
PTH – Osteoporosis
Thyroid is regulated by ..
and releases…
TSH and blood calcium levels
and releases T3, T4 and calcitonin
Parathyroid is regulated by… and releases…
Regulated by blood calcium levels
and releases PTH, triggers kidney to release calcitriol
calcitrol vs calcitonin
Calcitrol increases blood calcium and is an active form of Vitamin D, Calcitonin decreases blood calcium levels
