Animal Coordination, control and homeostasis
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- Created on: 29-05-19 17:14
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- Section 7 - Animal coordination, control and homeostasis
- Hormones
- Hormones are chemical messengers sent in the blood
- Produced in endocrine glands, making up endocrine system
- Pituatary gland - produces many hormones that regulate body conditions
- Thyroid gland - produces thyroxine, which regulates rate of metabolism, heart rate and temperature
- Adrenal glands - Produce adrenaline for a "fight or flight" response
- Ovaries - produce oestrogen involved in menstrual cycle
- Testes - produces testosterone, which controls puberty and sperm production in males
- The Pancreas - Produces insulin to regulate the blood glucose level
- Produced in endocrine glands, making up endocrine system
- Neurones: VERY FAST action, SHORT TIME, PRECISE AREA
- Hormones: SLOWER action, LONG TIME, GENERAL way
- Hormones are chemical messengers sent in the blood
- Adrenaline and Thyroxine
- Adrenaline prepares you for "fight or flight"
- When the brain detects a stressful situation, nervous impulses are sent to the adrenal glands, getting the body ready for action
- Activates processes that increase the supply of oxygen and glucose to the cells
- Thyroxine regulates metabolism
- Negative feedback system
- Body detects when the level of a system has gone above or below the normal level, it triggers a response to bring it back to normal again
- Used to keep the amount of thyroxine in the blood at the right level
- Negative feedback system
- Adrenaline prepares you for "fight or flight"
- The Menstrual Cycle
- Monthly sequence of events where the egg is released and uterus is prepared in case of fertilisation
- Stage 1 - Day one, the lining of the uterus breaks down and is released
- Stage 2 - From day 4-14, the lining is repaired until it becomes a spongy layer full of blood vessels for an egg to be implanted there
- Stage 3 - Egg released at day 14
- Stage 4 - Lining maintained until day 28 when the cycle repeats
- Controlled by 4 hormones: FSH (follicile stimulating hormone), Oestrogen, LH (Luteinising hormone), Progesterone
- Controlling Fertility
- Hormones can be used to treat infertility
- Clomifene therapy
- Clomifene drug causes more FSH and LH to be released and women to ovulate more regularly, improving pregnancy chances if the couple have intercouse during this period
- IVF
- Eggs are collected from the woman's ovaries and fertilised in a lab using the man's sperm. They are grown into embryos, and once they are tiny balls of cells 1 or 2 are transferred to the woman's uterus to improve the chance of pregnancy
- Clomifene therapy
- Contraceptives are used to prevent pregnancy
- Oestrogen can be used to prevent the release of an egg
- Progesterone can be used to reduce fertility by stimulating the production of thick cervical mucus, preventing the egg and sperm from meeting
- Barrier methods such as condoms or diaphragms
- Hormonal methods are more effective if used correctly, and couples don't have to worry about them before intercourse
- Hormonal methods have unpleasant side effects and don't prevent STIs
- Hormones can be used to treat infertility
- Homeostasis - control of blood glucose
- Maintaining a constant internal environment
- Blood glucose regulation
- the amount of glucose in your blood can't be too low or high
- Thermoregulation
- reducing and increasing body temperature based on warmth of environment
- Negative feedback systems keep conditions in the body steady
- Osmoregulation
- Keeping a balance in the water gained and the water peed, sweated and breathed out
- Blood glucose regulation
- Insulin and Glucagon control blood glucose concentration
- If blood glucose is too high, insulin is added
- If blood glucose is too low, Glucagon is added
- Maintaining a constant internal environment
- Diabetes
- Type 1 diabetes is caused by lack of insulin
- Pancreas produces little or no insulin
- Type 1 Diabetic people are treated with insulin therapy
- Insulin injected into subcutaneous tissue at mealtimes
- Also need to think about limiting simple carbohydrates and taking regular excercise
- Type 2 diabetes is caused by resistance to insulin
- Correlation between type 2 diabetes and obesity. People are classified as obese if they have a BMI of over 30.
- If waist-to-hip ratio is too big people are at higher risk due to increased fat around abdomen
- Type 2 diabetes can be controlled by eating a healthy diet and regular excercise
- Type 1 diabetes is caused by lack of insulin
- Hormones
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