Hormonal Communication - endocrine communication Flashcards
Endocrine system
A communication system using hormones as signalling molecules
Hormones
Molecules (proteins and steroids) that are released by endocrine glands directly into the blood.
Act as messengers which carry signals from endocrine glands to specific target organs or tissues
Target cells
- For non-steroid hormones
- They are cells that possess specific receptor on their plasma membrane
- Shape of the receptor is complementary to the shape of the hormone molecule.
What are the two types of hormones
- Protein and peptide hormones, derivatives of amino acids
- Steroid hormones
Examples of protein hormones
- Adrenaline
- Insulin
- Glucogen
Examples of steroid hormones
- Oestrogen
- Testosterone
How do protein hormones work?
- Not soluble in the phospholipid membrane and does not enter the cell
- Need to bind to the cell surface membrane and release a second messenger inside the cell
How do steroid hormones work?
-Pass through the membrane and enter the cell and the nucleus, to have a direct effect on the DNA
Endocrine glands
- Release hormones directly into the blood
- Ductless glands, consists of groups of cells that manufacture and release the hormone directly into the blood in capillaries running through the gland
What are the major endocrine glands in the body?
- Pituitary glands
- Thyroid gland
- Thymus
- Adrenal glands
- Pancreas
- Ovaries
- Testes
Target cells
The cells receiving endocrine signal
Target tissue
A group of target cells e.g. Epithelium of collecting ducts
What must target cells be like for non-steroid hormones?
-Target cells must possess a specific receptor on their plasma membrane that’ll the complementary shape of to the signalling hormone
Why can a hormone be carried in the blood without affecting all cells?
Because it must bind with a specific receptor to initiate changes in the cell
What are non-steroid hormones also known as?
First messengers
