hormones Flashcards
what system uses hormones
the endocrine system
what is an endocrine gland
a group of cells which are specialised to secrete chemicals (hormones)
what is the pituitary gland and where is it
produces growth hormone which controls growth of bones and muscles, also produces anti-diuretic hormone which increases reabsorption of water in kidneys gonadotrophins which control development of testes and ovaries
what does the thyroid gland do
produces thyroxine which controls rate of metabolism and rate that glucose is used up in respiration and promotes growth
what does the adrenal gland do
produces adrenaline which increases heart and breathing rate and increases blood sugar level,
what do the Testis do
produces testosterone which controls sperm production and secondary sexual characteristics
what does the pineal gland do
produces melatonin which affects reproductive development and daily cycles
what does the thymus do
produces thymosin which promotes production and maturation of white blood cells
what does the pancreas do
produces insulin which converts excess glucose into glycogen in the liver and glucagon which converts glycogen back to glucose in the liver
what does the ovary do
produces oestrogen which controls ovulation and secondary sexual characteristics, and progesterone and oestrogen which controls ovulation and secondary sexual characteristics, and progesterone which prepares the uterus lining for receiving an embryo
what two parts are the adrenal glands made up of
the adrenal cortex and the adrenal medulla
what hormones does the adrenal cortex produce
cortisol, aldosterone and androgens
what hormones does the adrenal medulla produce
adrenaline and noradrenaline
what are the three important digestive enzymes produced by the pancreas
amylases, proteases and lipases
what two hormones does the pancreas produce
insulin and glucagon
what hormone do the alpha cells in the islets of Langerhans produce and secrete
glucagon
what hormone do the beta cells in the islets of Langerhans produce and secrete
insulin
what is glycogenolysis
glycogen stored in the liver and muscle cells is broken down into glucose which is released into the bloodstream increasing blood glucose concentration
what is gluconeogenesis
the production of glucose from non-carbohydrate sources
how can blood glucose be decreased
exercise and glycogenesis
what is glycogenesis
the production of glycogen, when blood glucose concentration is too high, excess glucose taken in through the diet is converted into glycogen which is stored in the liver
what detects if the blood glucose concentration is too high
the b cells in the islets of Langerhans in the pancreas
what does insulin do to body cells when the blood glucose concentration is too high
binds to the glycoprotein receptors on cells and causes the tertiary structure of the glucose transport protein channels to change causing the channels to open more and allow more glucose in
how does insulin decrease the blood glucose concentration
increasing rate of glucose absorption in cells (particularly skeletal), increasing respiratory rate in cells, increases rate of glycogenesis, increasing the rate of glucose to fat conversion, inhibiting release of glucagon from a cells in the islets of Langerhans
why does insulin have to be constantly secreted to maintain its effect
it is broken down by enzymes in the liver cells
what cells in the body have glucagon receptors
liver and fat cells
how does glucagon raise the blood glucose concentration
glycogenolysis, reducing the amount of glucose absorbed by the liver cells, increasing gluconeogenesis
how does insulin secretion from a b cell work
glucose enters the cell by a glucose transporter and is metabolised inside the mitochondria resulting in the production of ATP, which binds to potassium channels and makes them close therefore depolarisation occurs and calcium channels open which allows calcium in which causes secretory vesicles to releases the insulin they contain by exocytosis
what causes type 1 diabetes
B cells in islets of Langerhans are unable to produce insulin
what causes type 2 diabetes
can arise from glycoprotein receptors being lost or being less responsive to insulin, or from insufficient insulin production in the pancreas.
what are the physical responses to the flight of fight
increased heart rate, dilate pupils, constricted arterioles, increased blood glucose levels, smooth muscle of airways relax, non-essential systems shut down, difficulty focusing on small tasks
