Hormonal Communication Flashcards
What is an endocrine gland?
A group of cells which are specialised to secrete chemicals (hormones) directly into the blood
What are the main endocrine glands in the body?
-Pituitary gland
-Thyroid gland
-Adrenal gland
-Pineal gland
-Thymus
-Pancreas
-Testis
-Ovary
Which gland secretes melatonin
Pineal
Which gland secretes insulin and glucagon
pancreas
Which gland produces growth hormones, anti-diuretic hormone and gonadotrophins?
Pituitary
Which gland produces thymosin?
Thymus
Which gland produces thyroxine?
Thyroid
What is the definition of hormone?
chemical messenger which is directly secreted into the blood to reach their target cells
What are the two types of hormones?
steroid and non-steroid
where would a steroid hormones receptor be?
in the cytoplasm or nucleus as it lipid soluble so can diffuse through membranes
Where would a receptor be found for a non-steroid hormone?
cell surface membrane
What are the advantages of hormonal rather than neuronal?
longer and widespread effect and effect could be permanent
What are the advantages of neuronal rather than hormonal?
faster, localised, specific and effect is temporary
where are the adrenal glands found?
on top of each kidney
what 2 parts make up an adrenal gland?
adrenal cortex and adrenal medulla
what hormones are produced by adrenal cortex?
essential hormones to life
cortisol- regulates metabolism
corticosterone-regulate immune response
aldosterone-controls blood pressure
what hormones are produced by adrenal medulla?
non-essential hormones stimulated by sympathetic nervous system
adrenaline
noradrenaline
What is able to act as an exocrine gland and endocrine gland?
Pancreas
What does an exocrine gland do?
produces enzymes and releases them via a duct
What enzymes does the pancreas release
amylase, lipase, proteases into the duodenum
What hormones does the pancreas produce?
insulin and glucagon
what tissue produces insulin and glucagon?
Both are produced in islets of Langerhans
insulin secreted by beta cells
glucagon secreted by alpha cells
What 3 factors increases blood glucose?
diet
glycogenolysis- breaking down glycogen
gluconeogenesis- making glucose from glycerol
What 2 factors decreases blood glucose?
respiration
glycogenesis- production glycogen
Which cells don’t have insulin receptors?
red blood cells
Which cells detect rise in blood glucose levels and secrete insulin?
beta cells
What 5 ways does insulin lower blood glucose concentration?
-Increases rate absorption of glucose by cells by when insulin binds to it’s glycoprotein receptor it changes the tertiary structure causing the glucose transport protein channels to open more.
-increases the respiratory rate of cells
-increases the rate of glycogenesis
-increases rate glucose to fat conversion
-inhibits the release of glucagon
What is insulin production an example of?
Negative feedback
Which cells in the body have glucagon receptors?
liver and fat cells
How does glucagon raise blood sugar concentrations
glycogenolysis
reduce the amount of glucose absorbed by the liver
increasing gluconeogenesis
What is the system of blood sugar concentration said to be
self regulating
7 steps insulin secretion
- normal conc k+ channels are open and K+ can diffuse out of the cell -70mV
- when glucose conc rises glucose enters the cell via a glucose transporter
- glucose is metabolised inside the mitrochondria producing ATP
- ATP binds to K+ channels causing them to close
- K+ can no longer diffuse out so depolarisation occurs -30mV
- Depolarisation causes voltage-gated Ca2+ channels to open
- Ca2+ enters the cell and causes secretory vesicles to release insulin via exocytosis
What type of diabetes is it when you cannot use insulin?
type 2 either b cells so not produce enough or body cells so do not respond
What type of diabetes is it when you cannot produce insulin?
type 1
What causes type 2?
obesity and lack of exercise
What is the treatment for type 1?
insulin injections
What is the treatment for type 2?
control weight and glucose intake, increases exercise, insulin injections
What can medically produced insulin be produced by?
GM bacteria
What could be the advantages of stem cell treatment for diabetes type 1 and what could be the concerns?
+ve
no concern over donor availability
reduced likelihood of rejection due to embryonic stem cells not being rejected
no longer required to inject themselves
-ve
scientists ability to control growth of stem cells is limited therefore is it a major concern it might induce tumours
Which part of the brain activates the fight or flight response?
Hypothalamus
What does the sympathetic nervous system activate in fight and flight response?
adrenal medulla (release adrenaline or noradrenaline) , smooth muscle and glands
What does the adrenal-cortical system do?
causes the pituitary gland to secrete hormone ACTH
What are 7 physical responses to fight or flight?
heart rate increases
pupils dilate
arterioles in skin constrict
blood glucose levels increase
smooth muscle of airway relaxes
non essential systems shut down e.g digestion
brain focused on threat
Why can’t adrenaline pass through cell membranes?
Polar/Hydrophilic
What is adrenalines main function?
Trigger liver cells to undergo glycogenolysis so glucose is released into the blood stream
(noradrenaline causes the other responses)
What happens when adrenaline binds to a receptor on the surface of a liver cell membrane?
Binds to receptor causing it to change shape
Which activates adenyl cyclase
Adenyl cyclase converts ATP to cAMP
cAMP activates protein kinases which phosphorylate and activates other enzymes converting glycogen to glucose
What nervous system controls heart rate?
autonomic
What node in the heart is the medulla linked to by motor neurones?
SAN
Which part of the nervous system increases heart rate?
sympathetic and is transmitted by the accelerator nerve
Which part of the nervous system decreases heart rate?
parasympathetic and are transmitted by the vagus nerve
Which two types of receptors provide info that affects the heart rate?
baroreceptors and chemoreceptors
Where would you find baroreceptors which affect heart rate?
aorta, vena cava and carotid arteries
Where would you find chemoreceptors which affect heart rate?
aorta, carotid artery and the medulla
what happens if the chemoreceptors detect a decrease in PH?
Increases frequency of impulses to SAN
SAN increases the heart rate
Increases blood flow and therefore is able to remove CO2 quicker
What happens if blood pressure is too high?
medulla sends impulses along the parasympathetic neurones to the SAN to decreases heart rate.
