Hormonal Communication Flashcards
what is the endocrine system made up of
endocrine glands which secrete chemicals called hormones which are released directly into the bloodstream
compare nervous and endocrine system
endocrine is long lasting
slower and involves chemicals over electrical impulses
what are hormones
they are chemical messengers which are secreted directly into the blood stream
steroid hormones
lipid soluble
pass through cell membrane and bind to steroid receptor forming hormone receptor complex
non steroid hormones
secreted directly
hormonal vs nervous system
hormonal has communcation by hromones
nervous has communication by nerve impulses
h trabsmission by blood system
n transmission by neurones
h response is widespread and slow
n is fast
h is long lasting
what is the adrenal gland made up of
the adrenal cortex
adrenal medulla
what is the adrenal cortex
The adrenal cortex: this produces hormones such as cortisol and aldosterone (outer region)
Adrenal cortex: The production of hormones by the adrenal cortex is controlled by hormones released by the pituitary gland in the brain. There are 3 main types of hormones produced by the adrenal cortex ( glucocorticoids, mineralocorticoids, Androgens)
what is the adrenal medulla
The adrenal Medulla : produces hormones such as adrenaline, it is the inner region of glands.
Adrenal Medulla : Hormones are released when the sympathetic nervous system is stimulated, occurs when the body is stressed. ( adrenaline and noradrenaline)
what is the main role of the pancreas
to control blood glucose levels and to produce and secrete hormones
hpw does the pancreas act as an exocrine gland and endocrine gland
produces enzymes and releases via duct into duodenum
endocrine gland, it produces hormones and releases into the blood
exocrine gland
Exocrine Gland : This contains an exocrine glandular tissue which is responsible for producing digestive enzymes and the pancreatic juice.
endocrine gland
Endocrine glands: Pancreas produces insulin and glucagon, these control blood glucose concentration. They contain islets of langerhans which are responsible for producing insulin and glucagon and secreting these hormones directly into the bloodstream.
islets of langerhans
it is lightly stained and is large it is an endocrine tissue which produces and secretes hormones
it contains alpha cells which produce and secrete glucagon
beta cells which produce and secrete insulin
acini
darker, small berry like, exocrine, produce and secrete digestive enzymes
alpha cells
p and s glucagon
beta cells
p and s insulin
what are the main factors of blood glucose concentration increasing?
- diet
- glycogenolysis ( this is when glycogen is broken down into glucose and released into the bloodstream)
- gluconeogenesis ( this is the production of glucose from non carbohydrate sources which is released into the bloodstream)
decreasing blood glucose concentration
- respiration
- glycogenesis (production of glycogen)
where is insulin produced
beta cells of the islets of langerhans in the pancreas
bgc levels is high
beta cells respond by secreting insulin directly into the bloodstream
what happens when insulin binds to its glycoprotein receptor
there is a change in the tertiary structure of the glucose transport protein channels causing channels to open allowing more glucose to enter
bgc levels low
insulin increases rate of absorption of glucose
increases respiratory rate
increases release og glucagon
how is insulin broken down
by enzymes in the cells of the liver
bgc returns to normal
b cells detect
reduce secretion of insulin
what is glucagon
it is produced by alpha cells of the islets of langerhans in the pancreas
what cells have glucagon receptors
liver and fat cells
how does glucagon raise blood glucose concentration
- glycogenolysis, liver breaks down glycogen store into glucose and releases into bloodstream
- reducing glucose absorbed
- increasing gluconeogenesis
negative feedback system of insulin and glucagon
booklet
control of insulin secretion mechanism
- Normal bgc levels, K channels in the plasma membrane of beta cells are open allowing potassium ions to diffuse out of the cell. There is a normal resting potential - BGC rises, glucose enters cells by a glucose transporter
- Glucose is metabolised in the mitochondria and ATP production occurs
ATP binds to the potassium channels causing them to close - Potassium ions no longer able to diffuse out of the cell, potential difference reduces and depolarization occurs
- Depolarization causes the voltage gated calcium channels to open
- Calcium ions enter cells and cause the secretory vesicles containing insulin to release via exocytosis
what is diabetes
it is when the pancreas does not produce insulin or cannot effectively respond to insulin
this means they have high blood glucose conc
type 1 diabetes
Unable to produce insulin (beta cells in the islets of langerhans do not produce any insulin)
Cause is unknown, cannot be prevented or cured
Evidence suggests that it arises as a result of an autoimmune response where the body’s own immune system attacks beta cells
It normally begins at childhood
Controlled by regular injections of insulin, it is insulin dependent, if they inject too much insulin their boody may experience hypoglycaemia
They have to continuously check their blood glucose concentration
type 2 diabetes
Patients with type 2 cannot use insulin or control their blood sugar levels
Their beta cells do not produce enough insulin or do not react insulin
This is because the glycoprotein insulin receptor on the cell membrane does not work.
Cells lose response to insulin so do not take up glucose and leave it in the bloodstream
It is typically due to excess body weight, physically inactivity, overeating of carbohydrate
Control their intake of diet and exercising
Drugs can be used which stimulate insulin production and slow down the rate at which the body absorbs glucose from the intestine.
‘fight or flight’ response
booklet
function of adrenaline
to trigger liver cells to undergo glycogenolysis allowing respiration to increase allowing muscle contraction
why can adrenaline not pass through the cell membrane
it is hydrophillic so it binds with receptors on surface of liver cells
second messenger model
Adrenaline binds to receptor, ADENYL CYCLASE is activated
ADENYL CYCLASE triggers the conversion of ATP into cAMP
Increase in cAMP level activates protein kinase which activate enzymes
what controls heart rate
autonomic nervous system, in particular the medulla oblongata in the brain
how does the medulla oblongata work
2 centres linked to san
one centre increases heart rate by sending impulses through the sympathetic nervous system
one centre decreases the heart rate by sending impulses through the parasympathetic nervous system
what are the 2 types of receptors which provide info affecting heart rate
baroreceptors
chemoreceptors
baroreceptors
detect changes in blood pressure
aorta, vena cava, cartoid arteries
chemoreceptors
chemical receptors which detect the changes in particular chemicals in the blood eg co2 located in cartpid arteries medulla and aorta
