Biology Paper 2 (Combined Higher)

?
  • Created by: rosiel05
  • Created on: 27-02-22 13:38

Homeostasis and Response

The Endocrine system:

Consists of the pituitary gland, thryoid gland, adrenal glands, pancreas, ovaries and testes.

Pituitary gland secretes growth hormones (targets whole body), LH and FSH (targets reproductive organs). These effect growth, release of an egg or testosterone, matures an egg or stimulates sperm production.

Thyroid glands secrete thyroxine which target the kidneys and liver. This effects the rate of metabolism, heart rate and temperature.

Adrenal glands secretes secrete adrenaline which targets vital organs like the brain. This effects the 'fight or flight' response.

The pancreas secretes both insulin and glucagon which both target the liver. Insulin lowers the blood glucose levels whilst glucogon increases the blood glucose levels.

The ovaries secrete oestrogen which targets the uterus. This effects in the menstrual cycle.

The testes secrete testosterone which targets the reproductive organs in a male. This effects the sperm production. 

Controlling blood glucose:

The pancreas detects the change in blood glucose levels. When there is a rise in blood glucose the pancreas secretes insulin into the bloodstream. The insulin travels through to the liver which absorbs the glucose and converts it into glycogen for storage. The blood glucose level returns to normal. However, if there is a fall in blood glucose levels then the pancreas will secrete glucagon into the blood stream. The glucagon travels to the liver which converts the gylcogen to glucose and releases it in to the blood. The blood glucose levels then return to normal. This is an example of negative feedback because it is an automatic system which switches on when there is too much or too little glucose in the blood.

Diabetes:

Diabetes is a condition that affects a persons ability to control their blood glucose levels.

In Type 1 diabetes, the pancrease can no longer make insulin needed. It can be treated by injecting insulin into the body.

In Type 2 diabetes, the liver is unable to recognise the insulin in the blood. It can be treated with a controlled diet and exercise.

Infertility:

Some women don't have enough levels of FSH to stimulate the maturation of their eggs. This means that they're infertile. Some modern reproductive technology that can help these women to give birth are:

- Fertility drugs (these contain a mixture of FSH and LH and are prescribed by a doctor) which boost levels of FSH and LH to cause an egg to be released in the ovaries.

- In Vitro Fertilisation (IVF) where FSH and LH are given to stimulate the growth of lots of eggs. Eggs are collected before being fertilised in a dish in a laboratory, using sperm from the father. These fertilised eggs grow into embryos and are implanted into the woman's uterus.

The advantage of fertility treatments is that they offer fresh hope to couples who can't conceive naturally. However, they also have disadvantages like how expensive they are, it can put lots of emotional and physical stress on the parents and it can also

Comments

No comments have yet been made