B1.2.2 - Control in the Human Body
- Created by: Hannahahmed2000
- Created on: 19-04-16 16:01
View mindmap
- B1.2.2 - Control in the Human Body
- Controlling Internal Conditions
- Internal conditions that are controlled include:
- Water leaves the body via the lungs when we breathe out.
- Ions and water are lost via the skin when we sweat, to cool us down.
- The excess ions and water are lost via the kidneys in the urine
- -Temperature, to maintain the temp at which enzymes work best
- -Blood sugar levels, to provide cells with a constant supply of energy
- Internal conditions that are controlled include:
- Hormones
- Many processes within the body are coordinated by chemical substances called hormones
- They regulate functions of many organs and cells.
- 1. Hormones are secreted by a gland into the blood
- .2. Hormones are transported around the body in thebloodstream to their target organs
- 3. Hormones cause a response from a target organ
- The Menstrual Cycle
- Hormones secreted by the pituitary gland and the ovaries control the thickness of the uterus lining and the release of an egg.
- Follicle-stimulating hormone (FSH)
- Causes eggs in ovaries to mature
- Stimulates ovaries to produce oestrogen
- Secreted by the pituitary gland
- Lutenising Hormone (LH)
- Secreted by the pituitary gland
- Inhibits production of oestrogen
- Causes ovulation
- Oestrogen
- Inhibits production of FSH so no more eggs mature that month.
- Causes uterus lining to thicken in first half of cycles
- High levels stimulate production of LH
- Secreted by the ovaries
- Progesterone
- Maintains thick uterus lining if egg is fertilised
- High levels stop the cycle
- Secreted by the ovaries
- Follicle-stimulating hormone (FSH)
- Hormones secreted by the pituitary gland and the ovaries control the thickness of the uterus lining and the release of an egg.
- Controlling Fertility
- Oral contraceptives
- Oestrogen and progesterone to inhibit FSH -> no eggs mature -> no eggs are released
- Early contraceptives contained large amounts of oestrogen caused significant side effects
- Modern pills contain a much lower dose of oestrogen or are progesterone only, which lead to fewer side effects
- Fertility drugs
- For women whose levels of FSH are too low to stimulate egg maturation
- Fertility drugs contain FSH and LH
- IVF
- 2. Eggs collected from ovaries and fertilised by sperm from the father
- 3. Fertilised eggs develop into embryos
- 4. When embryos are tiny balls of cells, one or two are inserted into the uterus
- 1. Mother given fertility drugs to stimulate maturation of several eggs
- Oral contraceptives
- Controlling Internal Conditions
Comments
No comments have yet been made