Hormonal communication Flashcards
Endocrine System
Consists of hormones transported by blood.
Slower than the nervous system and longer lasting with a broader area of response.
Examples
Endocrine glands
- Thyroid
- Thymus
- Adrenal
- Pituitary
- Pancreas
- Ovaries
- Testes
Features
Endocrine gland
- Ductless
- Contains cells that secrete hormones straight into the blood
Features
Exocrine gland
- Has a duct
- Not directly secreted into the blood
e.g. pancreas, salivary glands, sweat glands
Type of hormone
Protein + peptide hormones
- Not soluble in the membrane so CANNOT enter the cell.
- Protein based
e.g. insulin, glucagon, adrenaline
Steroid hormones
- Lipid based
- Can pass through the membrane
- Acts upon the DNA
e.g. sex hormones (oestrogen, testosterone)
How do hormones respond to signals?
- (non-steroid) Binds to complementary receptors on cell membrane
- Allows hormones to travel w/o affecting other cells
First messenger
- Protein based hormone that transmits a signal around the body EXTRACELLULARLY
Second messenger
- Intracellular signalling molecule
- Its release is triggered by 1st messenger
- Stimulates change in cell activity
1st +2nd messenger action
- 1st messenger binds to receptor (associated w/ G protein) on target cell membrane
- G protein activates adenyl cyclase which converts ATP to cAMP
- cAMP activates enzymes in cell causing a response
Adrenal glands
Endocrine glands located on kidneys
Medulla
ADRENAL GLAND
Centre of the gland
produces peptide hormones
Adrenaline
Cortex
ADRENAL GLAND
Surrounds the medulla
produces steroid hormones
What are some functions of the adrenal medulla?
- Secretes adrenaline to prepare the body for activity in response to pain/shock
Glycogenesis
The conversion of glucose to glycogen
Glycogenolysis
The conversion of glycogen to glucose
Gluconeogenesis
The conversion of amino acids/fats to glucose
