Endocrine System Flashcards
Thyroid Stimulating Hormone (TSH)
- targets thyroid gland
- stimulates the release of Thyroxin
- thyroid won’t stop producing FSH until thyroxin is released
- when hypothalamus reduces its level of TSH, causes a decrease in thyroxine production/release (negative feedback loop)
Prolactin
- targets mammary glands
- stimulates milk production (lacrosse geneis)
- stimulates development of mammary tissue
- increased prolactin levels during pregnancy suppress the production of LH which stops ovulation
- no disorders associated with
Posterior Pituitary
-backside of pituitary gland
Stores : oxytocin and antidouretic hormone (ADH)
They’re created by the hypothalamus and stored in the posterior pituitary
Non- steroid Hormones
Adrenaline, thyroxin, calcitonin, thymosin, prolactin, oxytocin, melatonin, insulin, glucagon, ACTH, LH, FHS, ADH, TSH, PTH, HGH
Steroid hormones
- fat soluble, able to pass through cell membranes
- cortisol, progesterone, testosterone, aldosterone, estrogen
Target organs
Organ that contains receptors for a particular hormone
Hormones
Chemicals that circulate throughout the blood and exert some measure of control over almost every organ and tissue in the body
Exocrine (gland)
Produce chemicals which travel directly to target organ through channels or ducts
Example: sweat glands, tear glands, salivary glands, mammary glands and they secrete substances such as sweat, saliva, tears, milk or digestive enzymes
Endocrine (gland)
Glands that don’t have ducts, hormones travel through the bloodstream for transport to target cells (organs)
Hypothalamus
Controls the endocrine hormone system (also the autonomic nervous system)
Non-steroid hormones (how they work)
- water based, unable to enter cells because they are not soluble in the membrane
- first messagers (hormone) binds to a receptor on the surface of the target cell, causing ATP to be changed into Cyclic AMP (cAMP)
- Cyclic AMP causes chemical reactions to occur within the cell
Tropic hormones
Hormones that regulate the hormone production of many other glands
Example: Thyroid Stimulating hormone (TSH) and ACTH
Antagonist hormones
Hormones that work against each other or have opposite effects on the body
Example: insulin and glucagon, parathyroid hormone and calcitonin
Hypersecretion
TOO MUCH
Over secretion of a hormone within the body
Adrenocorticotropic hormone (ACTH)
- targets adrenal cortex
- causes the adrenal cortex to produce cortisol and aldosterone
Negative feedback loop
Works to reverse or decrease changes in the body
Example: hypothalamus- pituitary feedback mechanism
*know and understand diagrams in notes
Hyposecretion
TOO LITTLE
Under secretion of a hormone within the body
Follicle Stimulating hormone (FSH)
Targets ovaries & testes
- causes maturation of a follicle within an ovary (females produce FSH in short burst)
-starts developmental of sperm (makes are always producing FSH)
Lutenizing hormone (LH)
Targets ovaries & testes
Females
- causes follicle to release an egg
- forms a corpus luteum (one day)
Males
-stimulates production of testosterone in males (without LH testosterone can’t be produced)
Positive feedback mechanism
Serves to increase the effect of an action
Example: oxytocin feedback loop
*know & understand diagrams in notes
Pituitary gland
Master gland
- located at the base of the Brain
- connected to hypothalamus
Signals from nervous system to hypothalamus to control over pituitary
- posterior pituitary
- anterior pituitary
Anterior pituitary
Located towards front of head, largest portion of pituitary gland
Produces 6 hormones
- human growth hormone (HGH)
- adrenocorticotropic hormone (ACTH)
- prolactin (PRL)
- thyroid Stimulating hormone (TSH)
- follicle Stimulating hormone (FSH)
- lutenizing hormone (LH)
Human growth hormone (HGH)
Targets long bones/tissues
- regulates growth/development of body tissues
- increases intestinal absorption of Ca, increasing cell division and growth in bones and cartilage
- stimulates protein synthesis and lipid (fat) metabolism (converts fats to sugars so they can be used)
Pituitary dwarfism
TOO LITTLE HGH
- insufficient production of HGH during childhood
- abnormally short bones
- can be treated with injections of HGH, but there are side effects
- normal torso and head
- small limps
Oxytocin during childbirth
- stimulates contractions of smooth muscles in the uterus
- when the baby’s hear pushes on the pressure receptors in the uterus, impulses are sent to the hypothalamus (positive feedback loop)
- causes oxytocin to be released from the posterior pituitary
- oxytocin stimulates uterine muscles to contract, contractions cause pressure receptors to release more oxytocin
Oxytocin
Targets : uterine muscles & mammary glands
- causes muscles to contract to help expel baby
- causes mammary glands to contract to release milk
Antidiurtic hormone (ADH)
Targets blood, arteries and collecting ducts of kidneys
- regulates sodium levels in blood
- causes damaged blood vessels to constrict to reduce blood loss
- causes kidneys to retain water
