B11 Hormonal Coordination
- Created by: Lucy Hart
- Created on: 29-02-20 19:40
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- B11 Hormonal Coordination
- B11.1 Principles of Hormonal Control
- endocrine system is composed of glands that secrete chemicals (hormones) directly into bloodstream
- pituitary - master gland, secretes variety of hormones into blood in response to changes in body conditions
- thyroid - controls metabolic rate
- pancreas - controls glucose in blood (insulin)
- adrenal - fight or flight (adrenaline)
- ovaries + testes - secondary sexual characteristics
- effects are slower + long lasting compared to nervous system
- endocrine system is composed of glands that secrete chemicals (hormones) directly into bloodstream
- B11.4 Role of Negative Feedback
- maintain a steady state so response causes the opposite
- thyroxine
- thryoxine in blood falls, detected by sensors, TSH increases stimulating production of TSH
- controlled by negative feedback whereas adrenaline isn't
- B11.6 Hormones + Mentrual Cycle
- lasts 28 days, day 14 ovulation, 14 days after lining shed
- 1. FSH (pitutiary) causes eggs to mature + stimulates oestrogen
- 2. oestrogen (ovaries) causes the lining of the uterus to develop, inhibits FSH + stimulates LH
- 3. LH (pituitary) - stimulates ovulation
- 4. progesterone - maintains the lining of the uterus, inhibiting FSH + LH
- 3. LH (pituitary) - stimulates ovulation
- 2. oestrogen (ovaries) causes the lining of the uterus to develop, inhibits FSH + stimulates LH
- B11.7 Contraception
- hormone based
- patch, injections, implant
- mixed pill
- progesterone + oestrogen
- inhibit production of FSH so no eggs mature + stop lining developing
- single pill
- progesterone
- less side effects
- chemical
- spermicides
- barrier
- condom
- diaphragm
- intrauterine devices
- small structures inserted in uterus
- surgical methods
- vasectomy - sperm ducts cut + tied
- hormone based
- B11.8 Infertility Treatments
- don't produce enough FSH
- IVF
- 1. mother given FSH to stimulate eggs followed by LH to bring eggs to ovulation
- 2. collect eggs + fertilise with sperm in lab
- 3. warm in environment for embryos to develop
- 4. inserted back into uterus
- 3. warm in environment for embryos to develop
- 2. collect eggs + fertilise with sperm in lab
- 1. mother given FSH to stimulate eggs followed by LH to bring eggs to ovulation
- DisAds - expensive, not always successful, health risks, multiple pregnancy
- B11.9 Plant Hormones + Responses
- responses of plants - tropisms
- phototropism - response to light
- auxin moves to dark side causing uneven growth resulting in shoot leaning towards light
- gravitropism - response to gravity
- shoots grow on side with most auxin making it bend + grow away from gravity
- roots grow more on the side with least auxin making it bend + grow down towards the force of gravity
- phototropism - response to light
- responses of plants - tropisms
- B11.10 Using Plant Hormones
- gibberellins - speeding up germination
- ethene - speeding up ripening
- auxin - weed killers
- 11.6 Human Reproduction
- female hormone
- oestrogen - rising levels at puberty (8-14) trigger development of secondary characteristic
- testosterone
- testes - trigger secondary charateristic (9-15)
- female hormone
- B11.2 Control of Blood Glucose Levels
- pancreas monitors + controls blood glucose concentration
- 1. blood glucose rises after meal
- 2. pancreas releases insulin which moves glucose to cells
- 3. glucose converted into insoluble carbohydrate + stored in liver (glycogen)
- 4. blood glucose falls
- 5. glucagon makes liver break down glycogen releasing into blood
- 4. blood glucose falls
- 3. glucose converted into insoluble carbohydrate + stored in liver (glycogen)
- 2. pancreas releases insulin which moves glucose to cells
- B11.3 Treating Diabetes
- type 1
- pancreas doesn't secrete enough insulin
- treatment - need replacement insulin (injections) before meals
- cures - transplant (not enough donors), transplanting pancreatic cells (limited success)
- pancreas doesn't secrete enough insulin
- type 2
- stop body responding to own insulin
- linked to obesity, lack of exercise
- treatment - exercise, balanced diet
- type 1
- B11.1 Principles of Hormonal Control
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