Endocrine System release chemical messages called hormones into the blood to act on target cells. Hormones only to get on the cell without a specific receptor. Certain glands that secrete chemical molecules (hormones) are secreted in small concentrations and get on the target cell. Hormones are chemical messengers produced by specialized glands in the endocrine system
Functioning of Hormones
- Growth and development
- Methabolism
- Stress Response
- Reporudction
- Mood and behaviour
Cascade Mechanism
A cascade mechanism means a gland (pituitary) that releases a stimulator or secretary hormones that will release a hormone acting as a signal to go further ahead without chemical changes for the process or to release other hormones.
Examples of Glands
- Endocrine glands release hormones into the bloodstream. They influence metabolism, reproduction, growth and other functions.
Pituitary Gland
(Not a part of the brain but attached to it.)
- Tells body what to do
- Tells other glands to release hormones
- Controls → Thyroid, adrenal glands + ovaries & testes
This kind of mechanism where in one stimulating hormone is triggering the other gland to release secondary hormones and to start or initiate a chemical or metabolic process: This is called the cascade mechanism: function as secretory.
- Secrets hormones that controls the maximum growth develop of the body
- Height
- Weight
- Secondary sexual characteristics (enlargement of testes and boobs
- Production of egg or sperm
Hypothalamus
- Area of the brain that links our brain to the hormone system is connected to the pituitary gland. Some hormones released by hypothalamus control the pituitary gland.
Thyroid Gland
- Controls BMR → Basal metabolic rate
- It influences metabolism, energy levels, body temperature, and calcium levels.
Hormone → Thyroid → Regulates rate of metabolism
↳ Can build in body only when iodized salt is present
If you don’t have enough iodized salt, your thyroid gland swells up/inflates. This is called Goitre, not enough iodized salt, therefore glands inflate.
Thyroxine low → Detected by pituitary
Thyroxine by thyroid gland ← stimulate TSH ↵
Pancreas
- Serve as endocrine and exocrine
- Insulin and glucagon → Endocrine secretion
- Regulate blood glucose concentration
- Pancreatic enzyme induct like amylase, lipase, trypsin → Exocrine secretion
Exocrine & Endocrine
| Exocrine | Endocrine |
| Enzymes | Hormones |
| Simple | Complex |
| Have ducts | Ductless → Release in blood |
| Large quantities | Small quantities |
| Target is located close to gland | Target is located away from gland |
LifeLine 
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