Endocrine System Flashcards
(25 cards)
What is the endocrine system made up of and what does it do?
Made up of endocrine glands and their hormones
Main func is to secrete hormones into bloodstream
What is a hormone?
A chemical messenger which targets a specific group of cells in order to cause that group of cells to do some activity or stop doing an activity
-each hormone acts on a diff kind of tissue called its target tissue
Examples of exocrine glands?
-Liver - bile is released into the gallbladder then through a duct into the small intestine
-Pancreas - releases pancreatic juice into the small intestine via a duct
Write out classes of hormones
Unbound hormone in hormones that are bound to proteins?
-The free unbound hormone appears to be the biologically active form of the hormone
Where do some carrier proteins come from?
Some carrier proteins are derived from the extracellular domain of the hormones cell surface receptor
Write out binding protein examples
Functions of hormones?
-Differentiation of reproductive and CNS in fetus
-Stimulation of growth and development
-Coordination of the male and female reproductive system
-Maintenance of internal environment
-Adaptation to emergency demands of the body
How are hormones regulated?
Feedback mechanisms
-Pos feedback
-Neg feedback (most)- another hormone or conc of a metabolic molecule
Features of Negative feedback and give an example?
-Acts as thermostat in home - as temp cools, thermostat detects the chnage and triggers heat to turn on and warm house and once temp is reached, heat turn off
-e.g body sugar increases after a meal so pancreas secretes insulin which tells the bodys cells to take in glucose. Once blood sugar levels reach normal, pancreas stops making insulin
-often used to maintain homeostasis
Feature of positive feedback and give an example?
-Control events that can be out of control and do not require continuous adjustment
-rarely used to maintain homeostasis
-E.g found in child birth - oxytocin stimulates and enhances labor contractions, as laber continues, more oxytocin is produced which intesifies contractions until baby is outside birth canal, oxytocin production stops and labor contractions stop
Homeostasis regulation?
-Often maintained by 2 hormones who have antagonistic effects
-each hormone does the opposite of the other
-if bp drops too low, pituitary releases ADH which causes kidneys to reabsorb water, if bp increases too much, heart will release ANH which causes the kidneys to reabsorb less water
Examples of human endocrine glands?
Pituitary, thyroid, parathyroid, adrenal, pancreas (islets of langerhans), testes and ovaries
Parathyroid gland?
-Func is to control metabolism of calcium - necessary for normal nerve and muscle function, blood clotting, healthy bone and teeth
-Located in back of thyroid gland (in neck)
-Hormone released is parathyroid hormone
-Under secretion results in nerve disorders, brittle bones and clotting problems
What is the Islet of Langerhans?
-Located on pancreas
-Hormones secreted are insulin and glucagon
-Insulin stimulates glucose uptake by cells
-Glucagon promotes conversion of glycogen (animal based carbs) to glucose
Where are the adrenal glands and what do they do?
-Located at the top of each kidney
-Releases hormones cortisone and adrenaline
-Cortisone func is to regulate the carb, protein and fat metabolism - promotes conversion of fats and proteins to glucose
-Adrenaline functions to raise blood sugar levels and increases heartbeat and breathing rates
Undersecretion of adrenaline?
Inability to deal with stress
Where is the pituitry gland found?
Round organ about the size of a pea, located behind the bridge of the nose and at the base of the brain
-master gland
What does the pituitary gland regulate?
-Growth
-Blood pressure
-Regulation of pregnancy
-Breast milk production
-sex organ func
-thyroid gland func
-metabolism
-water regulation in body via kidneys
-temp regulation
What is the pituitary gland composed of?
Complex structure of secretory cells, bv and nervous tissue lying in a bony cavity at the base of the skull
-anterior and posterior pituitary
What controls the pituitary gland?
Hypothalamus
-connected via pituitary stalk
Look at hypothalamus - pituitary - axis and table
Release of cortisol pathway?
In high stress
Hypothalamus releases Corticotropin-releasing factor (CRF) which acts on anterior pituitary to produce Adrenorticotropic hormone (ACTH) which acts on the adrenal cortex to produce glucocorticoids (especially cortisol)
What has a positive effect on cortisol production?
-Stress
-Hypoxia
-Hypoglycemia
-Hyperthermia
-Exercise
-Cortisol insufficiency
