B11 - Hormonal Condition Flashcards
Endocrine system
made up of glands that secrete hormones into the blood stream.
Pituitary gland
the master gland and is found in the brain. It secretes hormones of which some act on other glands and stimulate them to release hormones to bring about specific changes.
Process of hormonal control
Hormones => target organ => receptors on membranes pick up hormone molecules => cell response.
Pancreas
monitors and controls blood glucose concentration by releasing hormones in negative feedback loops
Glucose
the sugar used in respiration (soluble)
Glycogen
a storage carbohydrate found in the liver and muscles (insoluble)
Glucagon
a hormone that stimulates the liver to break down glycogen to glucose
What happens if blood glucose levels are high?
If blood glucose levels are high, the pancreas releases insulin which results in glucose taken in by cells and glucose converted to glycogen in liver. The blood glucose level fall returning to normal level of blood glucose.
What happens if the blood glucose levels are too low?
If the blood glucose levels are too low, the pancreas releases glucagon which results in glycogen being broken down to glucose in the liver and the amino acids/ fats are broken down. The blood glucose level rises returning to the normal level of blood glucose.
Insulin
a hormone created by the pancreas after glucose levels rise.
Type 1 diabetes characteristics
Kidneys excrete glucose in urine, glucose cannot reach cells leading to fatigue, fat and protein broken down as fuel leading to weight loss. This is genetic and developed at a young age.
Type 2 diabetes characteristics
linked to obesity and lack of exercise, genetic tendency
Treating Type 1 diabetes
replacement insulin injection before meals, controlling carbohydrate levels, regular meals, controlled exercise. Cured by: pancreas transplants (difficult, risky, immunosuppressants needed) or transplanting pancreatic stem cells.
Treating type 2 diabetes
balanced diet, losing weight, exercise, drugs – help insulin work more effectively, help pancreas secrete more insulin, reduce the amount of glucose absorbed.
Negative feedback
a system which works to maintain a steady state.
Thyroxine
a hormone produced by your thyroid gland, controls basal metabolic rate and it plays an important role in growth and development.
Basal metabolic rate
how quickly substances are broken down and built up, how much oxygen your tissues use and how the brain of a growing child develops
Thyroxine stimulating hormones (TSK)
hormone produced by the pituitary gland, stimulating thyroxine productions, involved in the negative feedback loop.
Adrenaline
hormone produced in adrenal glands in fight-or-flight solutions, not involved in such a clear-cut negative feedback system.
Causes of adrenaline production
increased heart rate and breathing rate, glycogen to glucose for respiration, dilated pupils (eye) to let more light in the eye, increased mental awareness and blood from digestive systems (to limbs).
Oestrogen
main female reproductive hormone produced by the ovaries. Triggers secondary characteristics: growth spurt, hair growth, breast development, female pattern of fat, menstruation.
Testosterone
main male reproductive hormone produces by testes. Triggers secondary characteristics: growth spurt, hair growth, larynx bigger, voice break, testes grow and become active. Also stimulates the production of sperm.
Stages of menstrual cycle
- FSH from the pituitary gland stimulates egg maturation and the ovary to produce oestrogen
- Oestrogen then stimulates growth of the lining, stimulates the release of LH from the pituitary and inhibits FSH
- After 14 days, LH stimulates ovulation – once ovulation is over LH levels fall again
- Progesterone is then secreted by the empty egg follicle in the ovary, which maintains lining and inhibits FSH and LH
- After 14 days, if the egg isn’t fertilised, the egg and lining are shed (menstruation)
Artificial control of fertility: mixed pill
contains low doses of oestrogen with some progesterone – this inhibits the release of FSH and therefore the maturation of the eggs, it prevents the lining from developing and creates a thick cervix mucus to prevent sperm from entering. However, side effects include: raised blood pressure, thrombosis, and breast cancer.
Artificial control of fertility: implant/injection
slowly release progesterone. Implant can last up to 3 years and is 99.95% effective. But it must be administered by a doctor, and an injection only lasts about 12 weeks.
Artificial control of fertility: Patch
contains low doses of oestrogen with some progesterone, but it must be replaced every 7 days.
Artificial control of fertility: Diaphragm/cramp
thin rubber cap over cervix. But, must be fitted by a doctor and if positioned poorly sperm may fertilise egg.
Artificial control of fertility: Intrauterine Device (IUD)
very effective structures inserted into uterus, lasting for 3-5 years and preventing early embryo implanting. May contain progesterone, but, must be inserted by a doctor and may cause period problems or infection.
Tropisms
the response of plant roots and shoots
Phototropism
the response of a plant to light, Auxin gathers on the the unlit side of the shoot making it bend towards the light
Gravitropism
the response of a plant to gravity in a shoot, auxin gathers on the lower side making it grow away from gravity
Auxin
a plant hormone controlling response to light and gravity through unequal distribution
Gibberelin
plant hormone initiating seed germination by triggering breakdown of food stores and stimulating stem growth.
Etherne
gaseous plant hormone controlling cell division and ripening of fruits
Uses of auxins
rooting powders, weed killers, plant cloning
Uses of gibberelins
speeding up germination fro barley seeds => malt, promoting flowering, increasing fruit size
Use of ethene
transporting unripe fruit
