B11(Hormonal Coordination) Flashcards
What is the endocrine system
-Glands that secrete chemicals called hormones directly into the blood stream
-the blood carries the hormone to a target organ where it produces an effect
Compared to the nervous system …
The effects of hormones are often slower but longer lasting
The pituitary gland is …
-The master the gland
-secretes several hormones into the blood in response to body conditions
Key endocrine glands are …
-the pituitary gland
-thyroid gland
-pancreas
-adrenal glands
-ovaries and testes
What does the pituitary gland do
-controls growth in children
-stimulates the thyroid gland to make thyroxine to control the rate of metabolism
-in women, stimulates the ovaries to produce and release eggs and make the female sex hormone oestrogen
-in men, stimulates the testes to make sperm and the male sex hormone testosterone
What does the thyroid gland do
Controls the metabolic rate of the body
What do the pancreas do
Controls the levels of glucose in the blood
What do the adrenal glands do
-Prepares the body for stressful situations
-“flight or fight response”
What do the ovaries do
Controls the development of the female secondary sexual characteristics and is involved in the menstrual cycle
What do the testes do
Controls the development of the male secondary sexual characteristics and is involved in the production of sperm
Your blood Glucose concentration is …
Monitored and controlled by your pancreas
The pancreas produces …
The hormone insulin, which allows glucose from the blood into the cells and to be stored as glycogen in the liver and muscles
The pancreas also produces…
Glucagon which allows glycogen to be converted back into glucose and release into the blood
How does The pancreas control glucose levels
What happens when the blood glucose levels are too high
-the pancreas secretes insulin
-insulin binds to the insulin receptors on cells
-the glucose channels are open and glucose leaves the blood and enters the cell
-the glucose is used by the mitochondria for respiration, this decreases blood glucose levels
What happens when the blood glucose levels are too low
-pancreas secretes glucagon
-stored glucose in the body is converted into glycogen as it is insoluble
-glucagon converts glycogen back into glucose
-causing glucose to be released in the blood
-which causes blood glucose levels to stabilise
How is type 1 diabetes caused
-if your pancreas does not make enough or any insulin
-your blood glucose concentration is not controlled
How is type 2 diabetes caused
-the pancreas still makes insulin but your body cells stop responding properly to the insulin you make
-type 2 diabetes is linked to obesity and lack of exercise
How is type 1 diabetes treated
-regular blood glucose tests
-injecting insulin to replace the hormone
How is type 2 diabetes treated
-a carbohydrate controlled diet
-taking more exercise
-losing weight
-taking drugs that help:
insulin work better on the body cells
Help your pancreas make more insulin
Reduce the amount of glucose you absorb from your gut
What is a negative feedback system
A system that maintains a steady state
Thyroxine is controlled by a negative feedback loop which is …
-if thyroxine levels rise, TSH levels fall, so thyroxine levels return to normal
-if thyroxine levels fall, TsH levels rise, so thyroxine levels return to normal
Adrenaline is produced…
In the adrenal glands
What does adrenaline cause
-Increased heart and breathing rate
-Stored glycogen in the liver to be converted to glucose for respiration
-The pupils dilate to let more light in
-Your mental awareness increases
-Blood to be diverted away from your digestive system to be the muscles of the limbs
The main female reproductive system hormone is ..
oestrogen produced by the ovaries
The main male reproductive hormone is …
testosterone produced by the testes
What does FSH do in the menstrual cycle
-secreted by the pituitary gland
-makes the egg follicles mature in the ovaries
-stimulates the ovaries to produce oestrogen
What does oestrogen do in the menstrual cycle
-secreted by the ovaries
-stimulates the lining of the uterus to grow again after menstruation
-high levels of oestrogen inhibit FSH and stimulate the release of LH
What does LH do in the menstrual cycle
-secreted from the pituitary gland
-stimulates the release of a mature egg from the ovary
-once ovulation has taken place, LH levels fall again
What does progesterone do in the menstrual cycle
-secreted by the empty egg follicle in the ovary after ovulation
-if the egg is fertilised it helps maintain a pregnancy
-inhibits FSH and LH
-maintains the lining of the uterus in the 2nd half of the cycle
What are the contraceptive methods
-oral contraceptives
-hormonal injections
-implants and patches
-condoms
-diaphragms
-spermicidal agents
-abstinence
-surgical sterilisation
FSH and LH can be used as..
A fertility drug to stimulate ovulation in women with low FSH levels
IVF uses ..
-FSH and LH to stimulate maturation of eggs that are collected, fertilised, allowed to start development and replace the uterus
Phototropism is …
-The response of a plant to light
Gravitropism is …
The response of a plant to gravity
Hydrotropism is …
The response of a plant to water
What are Auxins
-stimulates growth and cell division in shoots
-inhibits growth and cell division in roots
If lit evenly auxins are..
-evenly distributed in the shoot and the plant grows straight
If lit from one side auxins…
-gathers on the dark side so this side grows more and the shoot bends towards the light
How do auxins respond in phototropism
-Auxins move to the shaded region
-Auxins cause cell elongation
-shoot now bends towards light
-because cells in shaded region elongate quicker then non-shaded region
-so bends towards light
How do auxins respond in gravitropism
-If a shoot or root is placed on its side, auxins will accumulate along the lower side as a result of gravity; so the uppermost side has a lower auxin concentration
-In the roots, the lower side grows slower than the upper side (as auxin inhibits cell elongation and growth in the roots), so the root grows downwards
What are gibberellins
plant hormones that initiate seed germination
What does Ethene gas do in plants
-it is a plant hormone that controls cell division and ripens fruit
Auxins are used as …
Weed killers, rooting powders and in tissue culture
Ethene is used …
To control fruit ripening
Gibberellins can be used to …
-increase fruit size
-end seed dormancy
-promote flowering in the malting process
-increase the yield of sugar cane
How are the water levels controlled in the body If the water content of the blood is too high
the pituitary gland releases less ADH which leads to less water being reabsorbed in the tubules of the kidney (the tubules become less permeable to water)
How are water levels controlled in the body If the water content of the blood is too low
the pituitary gland releases more ADH which leads to more water being reabsorbed in the tubules of the kidney (the tubules become more permeable to water)
