What is Homeostasis?
“The regulation and maintenance of the internal environment of the body.

Conditions within the body must remain within a narrow range, like your body temperature.

Homeostasis involves keeping the internal environment within set ranges. This is achieved through the interaction and coordination of the body systems, endocrine and nervous system.

What does the endocrine system do?
The endocrine system controls the hormones.

In general, a gland selects and removes materials from the blood, processes them and secretes the finished chemical product for use somewhere in the body.
- They co-ordinate the organs to cooperate.
- Is based on the production of chemical messengers called hormones. If your endocrine system doesn’t work, you could get e.g diabetes.

Adrenal gland: adrenal cortex/adrenal medula, near kidney

Ovaries: female organs: produce two hormones, oestrogen and progesterone.

Oestrogen is vital for development of the female sex organs and features like voice and skin type. Progesterone controls the changes of the uterus in the menstrual cycle.

Testes: male organs: produce testosterone, a hormone who control the development of sex organs and features such as voice, facial hair and also produce sperms.

Feedback mechanisms: the right amount of hormone must be secreted at the right time for the proper functioning of the body.

The amount and timing of release of hormones is called the feedback mechanisms.

What is the lymphatic system?
1. Return fluid to heart

2. Help large molecules enter the blood, e.g hormones/lipids

3. Immune surveillance
- It is a network of tissues and organs that help rid the body of toxins, waste and other unwanted materials.
- And it is a part of the circulatory system
- And has a collection of lymphatic veesels and lymph nodes
- It transports lymph which is clear fluid containing lymphocytes
- Lymph is white cells

What is the function of the lymphatic system?
- To return fluid that has leaked out of the capillaries back to the circulation of the blood.
- To remove bacteria and other foreign particles from the lymph in the lymph nodes.
- To produce lymphocytes which produce antibodies, then the body will remember the same virus, bacteria etc the next time and know how to destroy it.