Endocrine system Flashcards
describe endocrine transmission
Chemical secreted
Low concentration
By a cell or group of cells
Sent to all parts of body
Via blood stream
Hormone acts only in cells with correct membrane receptor protein (target cells)
describe hormonal action
slow to act, can hit different parts of body, wide spread, effects persist
Give examples of endocrine systems
Hypothalamus
Pituitary
Thyroid
Parathyroid
Pancreas (Islets)
Adrenal (supra-renal)
GI tract endocrine cells
Gonads (ovaries and testes)
Placenta
Pineal gland
Thymus
What are the two classifications of hormones?
Steroids
Non-steroids-
-Amino acid derivatives
-Peptides
-Glycoproteins
What are steroid hormones based on?
a cholesterol ring structure
What are examples of steroid hormones?
Cortisol
Aldosterone
Testosterone
Oestrogen
Progesterone
What measurements are used commonly in biology?
mm- millimetres- 10-3
micro meters- 10-6
nano metres- 10-9
pm- 10-12
fentometres- fm,- 10-15
What are 2 types of amino acid derivative non steroid hormones?
Amines
Adrenaline (epinephrine)
Noradrenaline (norepinephrine)
Melatonin
Iodinated amino acids
Triiodothyronine
Tetraiodothyronine (thyroxine)
What are two types of peptide non steriod hormones?
long chain
short chain
Give and example of long chain peptide non steriod hormones
(proteins)
Growth hormone
Prolactin
Parathyroid hormone
Calcitonin
Adrenocorticotropic hormone
Insulin
Glucagon
GI tract hormones (secretin, CCK, gastrin)
give and example of short chain peptide non steriod hormones
Antidiuretic hormone
Oxytocin
Melanocyte stimulating hormone
Somatostatin
Thyrotropin releasing hormone
Gonadotropin releasing hormone
Atrial natriuretic hormone
Describe pro hormones
produced in endoplasmic reticulum as peptide hormone is produced inactive (prehormone). This is packaged in the Golgi apparatus.
Describe glycoprotein non steroid hormones and give an example
Protein with attached carbohydrate groups to amino acids
Follicle stimulating hormone
Luteinizing hormone
Thyroid stimulating hormone
Chorionic gonadotrophin
What hormone like structures have a paracrine effect?
local tissues, Prostagrandins
Leucotrienes
Thromboxanes
What is a function of local tissues?
Functions include:
Blood flow regulation
Haemostasis
Mucosal protection (stomach)
Inflammation
How do most non steroid hormones act?
through second messengers
Describe second messengers?
second messenger systems within the target cell
Two common ones are cAMP and Ca++
Steroid hormones can pass through the outer cell and directly reach intracellular receptors
How are most hormone systems regulated?
negative feedback
What is another name for excess secretion and decreased secretion?
hypersecretion and hyposecretion
sensitivity of target cells is subject to……
number of receptors
More receptors = upregulation
Fewer receptors = downregulation
describe hyperfunction
Excess production & secretion
Upregulation of receptors
Failure to metabolise hormone
Describe hypofunction
Hypofunction
Decreased production & secretion
Downregulation of receptors
Receptors non functioning
What can hyper/hyposecretion result in?
endocrine disorders, these can be complicated
What is the function of the hypothalamus?
Thermoregulation
Hormone secretion
Primary hormones
Trophic hormones
Circadian rhythms
Motivation
Thirst, feeding, sexual behaviour
Emotions
describe type 1 diabetes
insulin-dependent, decreased insulin secretion, destruction of beta cells
What is type two diabetes?
insulin independent, loss of insulin receptors
Where re adrenal glands found?
on top of the kidneys (supra retnal)
What are the cortex hormones?
aldosterone, cortisol, androgens
where are the cells that produce cortisol found?
zona fasciculata
what is the action of cortisols?
metabolic effects, permissive effect- immunological and anti inflammitory
Where is aldosterone produced?
zona glomerulosa
what is an action of aldosterone?
promotes reabsorption of sodium in kidneys, increases excretion of H, K
what does excess glucocorticoid cause?
Cushing’s syndrome
poor wound healing, moon face, thin skin, bruising
can be drug induced
what does excess androgens cause?
Adreno-genital syndrome
precocious development- height will not change though.
What is the adrenal medulla?
modified sympathetic ganglion- controlled by sympatheic nerves
