Physiology

Endocrine:

Hormone:
A hormone is a chemical substance that is secreted into the body fluids by one cell or a group of cells and has a physiological control effect on other cells of body.

Classification of Hormone:
I) according to the chemical nature:

1. Protein or peptides:

• ant. pituitary hormones
• post. pituiary hormones.
• pancreatic: insulin , glucagon
• parathyroid hormone

2. Steroids:
Adrenocortical hormone
Sex hormones
3. Derivatives of amino acid tyrosin:
Thyroid hormone
Adrenal medullary hormones (Epinephrine and norepinephrine)
II) according to the site of action:

1. General :
2.Local:
3.Tropoical:

Hormone Receptors

1. Cell membrane receptors: for protein and peptide hormones
2 Cytoplasmic receptors: for steroids

3. Nuclear receptors: for thyroid

FUNCTION OF ATP :

Virtually all forms of life use ATP, a nearly universal molecule of energy transfer. The energy released during catabolic reactions is stored in ATP molecules. In addition, the energy trapped in anabolic reactions (such as photosynthesis) is trapped in ATP molecules.

The function of ATP is to store energy within a cell. This way, energy within the body is not wasted, and can be stored for later use.( Biological Rechargable Battery)

ATP is referred to as currency because it can be “spent” in order to make chemical reactions occur. The more energy required for a chemical reaction, the more ATP molecules must be spent.

ATP serves as the major energy source within the cell to drive a number of biological processes such as  muscle contraction, and the synthesis of proteins. Extracellularly, ATP has been found to act as a neurotransmitter .

ATP receptors are widespread through the body. On its own it is known to have effects in the arteries, intestines, lungs, and bladder. It is also often released in tandem with other neurotransmitters, perhaps to add chemical stability.

Maintain energy dependant cell transport.