Flashcards in B5 - Homeostasis and Responce Deck (37):
the regulation of the conditions inside your body (and cells) to maintain a stable internal environment.
When the level of something is too high or too low
Receptor detects a stimulus - level is too high/low
The coordination centre receives and processes the information, then organises a response.
Effector produces a response, which will counteract the change and restores the optimum level - the level decreases.
The nervous system
This consists of the brain, the spinal chord. The CNS is connected to the body by sensory neurons and motor neurons.
The neurons that carry information as electrical impulses from the receptors to the CNS
The neurons that carry electrical impulses from the CNS to effectors
All your muscles and glands, which respond to nervous impulses.
The response system
Cells that detect stimuli
The connection between two neurons. The nerve signal is transferred by chemicals which diffuse across the gap. These chemicals set off a new electrical signal in the next neurone
Chemical molecules released directly into the blood. They are produced in various glands. These glands make up the endocrine system
The pituitary gland
- produces many hormones that regulate body conditions
- these hormones act on other glands, directing them to release hormones that bring about the charge
- Produce oestrogen
- Produce testosterone, which controls puberty and sperm production
- produces thyroxine, which is involved in regulating things like rate of metabolism, heart rate and temperature.
- Produces adrenaline, which is used to prepare the body for a "fight or flight" response
- Produces insulin, which is used to regulate the blood glucose level
Blood glucose level too high
- Insulin secreted by the pancreas
- Glucose moves from blood into liver and muscle cells.
- Insulin makes liver turn glucose into glycogen
Blood glucose level too low
- Glucagon secreted by the pancreas
- Glucose released into blood by liver
- Glucagon makes liver turn glycogen into glucose
Type 1 diabetes
- Where the pancreas produces little or no insulin at all.
- Insulin therapy - injections of insulin throughout the day, most likely at mealtimes
Type 2 diabetes
- Where a person becomes more resistant to their own insulin
- can be controlled by eating carbohydrate-controlled diet and getting regular exercise.
- Day 1 - the uterus lining breaks down for about 4 days
- Day 4 - Day 14 - The uterus lining builds up again into a thick spongy layer full of blood vessels, ready to receive a fertilised egg.
- Day 14 - An egg is developed and released.
- Day 14 - Day 28 - The wall is then maintained until day 28. If no fertilised egg has landed on the uterus wall by day 28, the spongy lining starts to break down and the cycle repeats
Oestrogen to reduce fertility
- If the level of oestrogen is permanently high, it stops the production of FSH. After a while egg development and production will stop.
Progesterone to reduce fertility
- Produces a thick mucus which will prevent any sperm reaching the egg
- Contains oestrogen and progesterone. 5cm x 5cm patch stuck to the skin. Lasts one week
- Inserted under the skin of the arm. Continuous amount of progesterone. Stops the ovaries releasing eggs. Lasts for 3 years
- Contains Progesterone. Lasts 2-3 months
- T-shaped device that is inserted into the uterus to kill sperm.
Plastic - release Progesterone
Copper- prevent the sperm surviving in the uterus
- shallow plastic cup
- fits over the cervix to form a barrier
- has to be used with spermacide
- A substance that disables or kills the sperm
- only 70%-80% effective
- Cutting or tying the fallopian tubes in a female or the sperm duct in a male. Very small chance that the tubes can rejoin
Hormones to increase fertility
- The hormones FSH and LH can be given to women in a fertility drug to stimulate ovulation.
- helps a lot of women to get pregnant
- doesn't always work
- Too many eggs resulting in unexpected multiple pregnancies (twins,triplets etc.)
- Collecting the women's eggs and fertilising them in a lab using the man's sperm
- ICSI - Where the sperm is directly injected into an egg
FSH and LH are given before egg collection to stimulate several eggs to mature.
- Give an infertile couple a child
- Multiple births
- success rate of IVF is low
People are against IVF
- Results in unused embryos that are eventually destroyed. Because of this people think it is unethical because each embryo is a potential life.
- The genetic testing of embryos before implantation also raises ethical issues as some people think it could lead to the selection of preferred characteristics, such as gender or eye colour
- Released by the adrenal glands (just above the kidneys)
- Gets the body ready for "fight or flight" by triggering mechanisms that increase the supply of oxygen and glucose to cells in the brain and muscles.
- Released by the thyroid gland (which is in the neck)
- Stimulates protein synthesis for growth and development
- Released in response to thyroid stimulating hormones (TSH), which is released from the pituitary gland
- A negative feedback system keeps the amount of thyroxine in the blood at the right level