Endocrine disorders Flashcards
Define hormones?
chemicals that travel through the blood stream until they reach their target organ and exert an affect.
Define Autocrine?
relating to a hormone that has an effect on the original cell that produced
Define Endocrine?
relating to a hormone that is transported in the blood stream to the target audience.
Define Exocrine
relating to a hormone that is released through a duct or ducts
what is the difference between endocrine and exocrine glands?
Endocrine glands secretes its products i.e hormones directly in to the blood stream. Exocrine glands secretes its products i.e enzymes into ducts that lead to target tissues. for example the salivery gland secretes saliva into the collecting duct which leads to the mouth.
Define paracrine?
relating to a hormone that has an effect on local cells
explain negative feed back.
Negative feed back is where increased levels of hormone are detected by a gland and result in decreased levels of homone production by that glands. the secretion of many hormones is controlled this way.
Explain positive feed back.
postive feed back is when increased levels of a hormone are detected by a gland and result in even more hormone being being produced by the gland
What are the four groups hormones can be grouped in to according to the type of molecules present?
*Protiens - i.e growth hormone, insulin
*peptides (short chains of amino acids) - thyroid - stimulating hormone (TSH) oxytocin
*amines (compounds containing basic nitrogen atom)
steroids - cortisol, progestion
What part of the brain controls the endocrine system?
Hypothalamus. it controls releasing hormones which in turn control the pituitary gland.
How does the pituitary gland respond to the hormones secreted by the hypothalamus?
It responds by producing stimulating hormones which are sent out to individual organs.
what does the pituitary gland comprises of? and which part produces what hormones?
Adenohypophysis (antererior pitutary gland)
- adrenocorticotrophic hormone (ACTH) - targets adrenal gland cortex and stimulates release of corticosteroids ad mineralocorticoids.
- follicle-stimulating hormone (FSH) - stimulates males to produce spermatogensis and females it targets the overies to produce growth follicles which contain ova
- Growth hormone (GH)/somatotropin - act on tissue in the body stimulating growth by increasing uptake of amino acids and protein production.
- luteinzing hormone (LH) - has many function but basically stimulates the release of testosterone and causes ovulation
- prolactin - targets mammary glands to stimulate milk development in pregnancy
- thyroid-stimulating hormone (TSH) targets the thyroid and stimulates the release of thyroxine.
Neurohypophysis (posterior pituitary gland):
- antidiuretic hormone (ADH)/vasopressin - is released in respose to increased plasma osmotic pressure and causes an increase in the resorption of water thus increasing plasma volume and decreasing urine output.
- oxytocin - causes contraction during parturition and act on the mammory gland lining resulting milk let down
How is melatonin produced and what is it responsible for ?
It is produced by the pineal gland in respoinse to daylight length. it is responsible for functions of the body related to photoperiods such as reproduction, behavior and coat changes.
what does calcitonin control?
blood calcium levels
What hormones does the thyroid produce and what do they do?
thyroxine, triiodothyronine. they act on most cells in the body controll metabolic rate essential for normal growth have effects on skin, skeleton, cardiovascular system, neurological systems and reproductive function
what hormone does the parathyroid glands produce and what does it do?
parathyroid hormone:
- control blood calcium in a similar way to calcitonin i.e increasing releasing calcium from the bones and increasing absorption form the intestine and accelartes vitamin D activation and decrease urinating calcium
- also decreases blood phosphate concentrations by increasing phosphate deposition in bone.
what does the endocrine section of the pancreas consist of and what cells produce which hormones
islets of langerhans - a group of specalised cells that make and secrete hormones.
- Alpha cells- produce glucagon - it is stimulated when low BG volume and acts on the liver to breack down stored glucose and to increase production
- beta cells produce insulin - stimulated when high blood glucose and causes uptake of glucose into cytoplasm of cells. it also help with the production of glycogen, triglycerides and proteins
- delta cells produce somatosatin - regulates glucagon and insulin
How do hormones prolactin and thyroxine help birds?
they help control the cycles of feathers molting and regrowing.
what hormone do reptiles produce rather than oxytocin during egg production?
vasotocin
what gland is responsible for the production of melatonin in reptiles? and what does melatonin do for them?
parietal eye (in reptiles such as iguana) and pineal gland and it controls seasonal variartions in reproduction and activity.
