Hormonal communication Flashcards
What does the endocrine system use to send information about changes in the environment around the body?
Hormones
What is the endocrine system made up of?
Endocrine glands
What is an endocrine gland?
Group of cells that are specialised to secrete hormones directly into the bloodstream.
Pineal Gland
produces melatonin
Which affects reproductive development and daily cycles.
Thymus
produces thymosin
Which promotes production and maturation of white blood cells.
Pancreas
produces insulin, and glucagon
What does insulin do?
converts excess glucose into glycogen in the liver.
What does glucagon do?
converts glycogen back into glucose in the liver
Pituitary gland
produces growth hormones,
produces anti-diuretic hormones
produces gonadotrophins
Thyroid gland
produces thyroxine
which controls rate of metabolism and rate that glucose is used up in reparation.
Adrenal Gland
produce adrenaline
which increases heart rate and breathing.
testis
produces testosterone
Ovary
produces oestrogen, progesterone
When hormone are diffused out of the blood, the bind to what to stimulate a response ?
Target cells
Why is hormonal communication slower and less specific than neuronal?
Hormones are not released directly onto the their target cells.
Why is hormonal communication long-lasting and more widespread than neuronal?
hormones are not broken down as quickly as neurotransmitters.
What are the approximate size of adrenal glands?
3cm in height
5cm in length
What is the Adrenal cortex?
Outer region of the gland.
produces cortisol and aldosterone
What is the adrenal medulla?
the inner region of the gland.
produces adrenaline.
What glad controls the production of hormones by the adrenal cortex?
Pituitary Gland
What are the 3 types of hormones produced by the adrenal cortex?
Glucocorticoids
Mineralocorticoids
Androgens
What do glucocorticoids do?
Regulates metabolism, by controlling how the body coverts fats, proteins and carbohydrates in to energy.
Regulates blood pressure in response to stress.
What is a type of glucocorticoid hormone?
corticosterone.
What does corticosterone do?
Works with cortisol to regulate immune response and suppress inflammatory responses.
What is the main mineralocorticoid produced?
aldosterone
What does aldosterone do?
controls blood pressure by maintaining the balance between salt and water concs.
What are androgens?
small amounts of male and female sex hormones.
When are hormones released from the adreanl medulla?
when the sympathetic nervous system is stimulated
occurs when the body is under stress
What are the 2 hormones secreted by the adrenal medulla?
adrenaline
noradrenaline
What does adrenaline do?
increases heart rate by sending blood to the muscles quickly
Increases blood glucose levels by converting glycogen into glucose in the liver.
What does noradrenaline do?
Works with adrenaline in response to stress.
What are the 2 main functions of the pancreas in the body?
its an endocrine gland
its an exocrine gland
What is the exocrine glandular tissue that the panaceas is made from responsible for?
producing digestive enzymes, know as pancreatic juices, which are secreted into the pancreatic duct.
Amylase
breaks down stack into simple sugars.
protease
breaks down proteins into amino acids
lipases
breaks down lipids into fatty acids and glycerol
What do the islet of langerhans do?
produce insulin and glucagon, and secreting them into the bloodstream
What cells are found in the islets of langerhan?
alpha cells
beta cells
What do alpha cells produce?
glucagon
What do beta cells produce?
insulin
3 ways that blood glucose levels can be increased.
Diet
Glycogenolysis
gluconeogenesis
How can diet increase your blood glucose levels?
When you eat carbohydrates or sugary foods, they are broken down into glucose, this is then absorbed into the blood stream
What is Glycogenolysis?
Glycogen that is stored in the liver and muscles can be broken down into glucose
What is Gluconeogenesis?
the production of glucose from non-carbohydrate sources.
e.g the liver is able to make glucose from glycerol and amino acids.
What are the 2 ways that blood glucose levels can be decreased?
Respiration
Glycogenesis
What is Glycogenesis?
the production of glycogen
How can Glycogenesis decrease blood glucose levels?
excess glucose is converted into glycogen, which is stored in the liver.
How does insulin lower blood glucose levels?
5 ways
increases the rate of glucose absorption ( mainly in skeletal muscle cells)
increases respiratory rate of cells ( causing a higher uptake of glucose in the blood)
increases the rate of glycogenesis ( turns glucose into glycogen)
Increasing the rate of glucose to fat conversion.
inhibiting the release of glucagon
What cells detect the blood glucose returning back to normal?
Beta cells
When the blood glucose levels falls below a certain level the beta cells reduce their secretion of what ?
insulin
How does glucagon raise blood glucose levels?
glycogenolysis- break down of glycogen into glucose
reduces the amount of glucose absorbed by the liver cells
increases gluconeogenesis - conversion of amino acids and glycerol into glucose
How could you describe the maintenance of blood glucose levels in the blood
self regulating
Describe the mechanism by which insulin is released from the beta cells in the islets of langerhan.
- at normal blood glucose concentration, potassium channels in the beta cells open. Potassium diffuses out.
- When blood glucose conc rises, glucose enters the cell by a glucose transporter.
- glucose is metabolised, in the mitochondria= ATP
- ATP binds to the potassium channel = channels close
- as potassium ions can no longer diffuse, the PD reduces and depolarisation occurs
- depolarisation = VG calcium channels to open
- calcium ion enter = secretory vesicles to realise insulin by exocytosis
Describe type 1 diabetes
unable to produce insulin
the beta cells in the islets of Langerhan do not produce insulin
cause unknown
Describe type 2 diabetes
cannot effectively use insulin and controls there blood sugar levels
Either because beta cells cannot produce enough insulin, or their body cannot respond to it.
This is because the glycoprotein on the insulin receptor doesn’t work
What are some common symptoms of diabetes?
excessive need to wee
constant hunger
weight loss
tiredness
blurred vision
glucose present in wee
What is type 1 diabetes controlled by ?
regular insulin injections
If someone injects themselves with too much insulin, what could they experience?
hypoglycaemia
What is hypoglycaemia?
very low glucose levels
If someone doesn’t inject themselves with enough insulin why can they experience?
Hyperglycaemia
Ways to treat type 2 diabetes
diet
exercise
drugs that stimulate the production of insulin
