HES 111 midterm I Flashcards
What is the endocrine system?
A series of organs throughout the body that secrete horomones in response to stimulus
Name some bodily functions the endocrine sytsem is involved in?
metabolism, reg of gene expression, growth, reproduction
What are the two categories of endocrine organs and what are some examples in each
Endocrine: ant pit, thyroid, parathyroid, thymus, adrenal corte, pancreas, ovaries/testes
Neuroendocrine: hypothalamus, pineal gland, post pit, adrenal medulla
What are the 4 neuroendocrine organs?
Hypothalamus, adrenal medulla, post pit and pineal gland
what must a horomone bind to to exert action?
Its receptor
What is the difference between a hormone and neurotransmitter?
Hormone travel in bloodstream and secreted by endocrine gland. - long distance
Neurotransmitter - travel across synaptic cleft, secreted by neuron - short
BOTH: bind to a rececptor on a cell
What is a neurohormone?
a hormone secreted into blood by neuroendocrine cells (neurons)
What are the 2 main classes of hormones? Examples?
- amino acid based
- amines: epinephrine, norep (deriv of tyrosine), depamine, thyroid
- Peptide: insulin, GH - Lipid based
- Steroids: etrogen, testosterone, cortisol
How do the 2 classes of hormones behave differently
how they travel in blood, how target. cells recognize/receive, half life
Are amino acid based hyrdophobic or phyllic and where does it bind?
Hydrophyllic, binds on plasma membrane of target cell
Are steroid hormones hydrophobic or phyllic, where do they bind?
Hydrophobic — pass thru plasma membrane and bind in the cytosol in the nucleus of target cells
Both steroid and peptide horomones trigger a ________ response. Steroid horomone usually involve modification of…
INTRAcellular response, gene expression
How are hormones eliminated?
- Taken up by target cell
- Broken down (metabolized by liver) —- eliminated via kidneys
what does rate of hormone elimination depend on?
structure, and wether its bound to a carrier protein
what is hormone half life?
time taken for hormone concentration to reduce by half in the blood
Are hydrophobic/phyllic horomones bound to carrier proteins? How does this effect half life?
Hydrophobic (steroids) are bound to carrier proteins (albumin) so they have longer half lives (min–hrs)
What are 3 ways that hormone secretion is regualted
Other horomones, other molecules (eg ca), glucose (glucose uptake by pancreatic cell triggers insulin secretion, neurotransmitters (symp neurons trigger epinephrine, norepinephrin)
Where do the horomones produced in the hypothalamus go? What is directed in the hypothalamus?
to the post. pit, directs horomones from ant pit
What 2 horomones does hypothal produce for secretion by___
post pit: anti-diuretic horomone (ADH) – to kidneys – water reabsorption back into blood
Oxytocin – uterus and mammary gland: uterine contraction and milk release
What type of horomones (made by hypothalamus) trigger release from the ant pit?
TROPIC - a hormone that triggers release of another horomone
What are 5 tropic horomones released by hypothalamus?
thyroid releasing hormone, corticotropin releasing hormone, prolactin releasing hormone, gonado-tropin releasing horomone, GH releasing hormone
what does prolactin releasing horomone lead to?
prolactin releasing hormone — prolactin — mammary gland –milk production
what is the path of thyroid releasing hormone?
thyroid releasing hormone — thyroid stim hormone – thyroid gland ( thyroid stim and secretion)
Path of corticotropin releasing hormone?
triggers adrenocorticotropic horomone then to adrenal cortext which secretes cortisol and aldosterone
Path of gonadotropin releasing horomone
lutenizing horomone and follicle stim horomone — to the female and male gonads —
IN FEMALE: Synth and secretion of estrogen, progesteron, follicle maturation, ovulation
IN MALE: synth, prep and seretion of testosterone
Path of growth horomone releasing hormone
Growth hormone secretion — liver, adipose tissue, muscle tissue, boen and cartillage, — involved in metabolic processes that release energy for fuel rpod incr blood glucose and promote growth.
What is the main function of the growth hormone?
Regulate growth of target tissues
short term effects are… What is the goal of short term effects?
Metabolic – fat breakdown, new glucose in liver, inhibit gluc uptake in skel muscle
GOAL: Make glucose + fatty acids available for use for fuel and growth
What is the long term effect of GH?
Tropic effect - Trigger release of Insulin-like growth factor (IGF)
Where are thyroid and parathyroid glands located
Thyroid - ant neck, superficial to trachea
Parathyroid - post surface of thyroid
what are the 3 tiers of horomone control form the hypothalamus?
1: hyporthal releases hormones
2: ant pit releases hormones
3: target organs release hormones
4: effects: hormone levels increase - effects on other cells(return to normal range)
What are the the 3 hormones secreted by thyroid: 2 main functions
T3(triiodothyronine) + T4 (thyroxine) + calcitonin
- Reg metabolism - set basal metabolic rate
- Reg body temp - thru metablism
What does the parathyroid gland secrete? It is secreted in response to_____ so it therefore _____
Parathyroid horomone - secreted in reponse to LOW BLOOD CA so therefore INCREASES blood calcium
3 ways PTH increases blood ca
1) Stimulates osteoclasts – incr ca release
2) increase absorbtion of ca by small intestinee
3) increase reabsorption in kidneys
What does IGF do? Where does it come from? Goal?
(insulin like growth factor)
- affecrs cells: protein synth, division, incr glucose uptake in cells
Long term effect of GH
Goal: growth: during developmental years (GH continues to reg blood glucose and muscl growth thru adulthood)
Calcitonin is secreted by ____ and responds to ____ blood ca therefore the effect ____
Secreted by thyroid hormone, responds to high blood ca by lowering blood ca:
1) inhibits osteoclasts
What neurohormones are secreted by adrenal medulla?
epinephrine and norepinephrine
What type of horomones does the adrenal medulla secrete? what types does the adrenal cortex secrete?
adrenal medulla: neurohormones: epinephrine and norepinephrine
Adrenal Cortex: steroid hormones: aldosterone and cortisol
What does aldosterone do? Secreted by?
Regulation of fluid, elctrolyte and pH balance in blood
secrete by the adrenal cortex
what does cortisol do? secreted bY?
promote catabolic rxns in order to provide fuel for stress response
for ex: gluconeogenesis (gluc production in liver)
protein breakdown
fat breakdown
ALSO Inhibit inflammatory responses
Pancreatic islets consist of what type of cells?
alpha, beta, delta
which cell is insulin produced and secreted from? Secrete in respont to..
B (beta) cells. high blood glucose
what cell is glucagon produced and secreted from
a cells - secreted in response to low blood sugar
What are the two types of membranes surrounding the heart?
fibrous pericardium - outer conn tissue
serous pericardium - inner forms 2 layers
what are the two layers if the serous pericardium
parietal layer: fused to inner surface of fibrous pericardium
visceral layer: inner layer closest to heart wall
pericardial cavity: between 2 layers - filled w serous fluid (pericardial fluid) - lubricant decreases friction as heart beats
Which membrane is a part of the heart wall
visceral pericardium (epicardium)
What are the 3 layers of the heart wall?
epicardium - myocardium - endocardium
what layer of heart wall contains fat deposits
epicardium (visceral pericardium)
what is the main component of wall of the heart? what does it contain
myocardium - contains myocytes (cardiac muscle cells). Also specialized pacemaker cells and conn tissue
what is the innermost layer of the heart?
endocardium - faces lumen of heart chambres: simple squamous epithelium + layers of conn tissue w collagen and elastic fibres
what compartments recieve blood from veins
atria
what part of heart ejects blood into arteries
ventricles
What are the major systemic veins?
sup and inf vena cava
why are ventricles larger w thicker walls
because they are stronger pumps
wharts the major systemic artery
aorta
major vessels of pulm circuit?
r and L pulm arteries and veins
which atria is larger
the right is larger, thinner, more anterior
What are right and left ventricles seperated by?
interventricular septum
what are the valves between the atria and ventricles
Atrioventicular valves (AV valves)
Tricuspid - on right side
Bicuspid/mitral - on left side
What are the valves between ventricles and pulmonary arteries
Semilunar valves (Also tricuspid)
- Pulmonary valves - between r ventricle and pulm trunk
- aortic valve: between left ventricle and aorta
what is the purpose of valves
keep blood flowing in one direction
Blood flows in response to - —- gradients
pressure
what happens when pressure in ventricle is high (greater than aorta or atrium)
Pushes aortic valve open, if greater than atrium closes atrioventricular valves (tricuspid or biscupid(mitral)
what happens when pressure in aorta is greater than ventricle
closes aortic semilunar valve
what happens if pressure in the atrium is greater than ventricle
Opens AV valves
Describe the steps of blood flow thru the heart
1) blood in systemic capillaries delivers oxygen to body
2) systemic veins bring deoexygentaed blood back to right atrium
3) Blood passes to right ventricle thru tricuspid valve
4) then thru pulmonary valve to pulmonary veins (pulmonary trunk)
5) to pulmonary capillaries in lungs where blood becomes oxygenated
6) pulm veins returns oxygenated blood to left atrium
7) blood goes from left atrium thru bicuspid (mitral valve) to left ventricle
8) left ventricle pumps thru aortic valve to aorta
9 ) aorta delivers blood to systemic capillaries and body
what are the two types of cells in the myocardium
myocytes - majority (99%)
pacemaker cells - 1%
what is the source of force production of the heart muscle?
myocytes
what generates spontaneous, rythmic action potentials
pacemaker cells
do pacemaker cells contribute to the contractile force of the heart
no - just a signal for myocyte contraction
what joins myocytes together?
intercalated discs
what connects pacemaker cells to contractile cells?
Intercalated discs
what are intercalated discs made of?
Desmosomes: hold the cells together
Gap junctions; allow ions to pass rapidly form one call to another