Define ‘hormone’, Name The Chemical Classes Of Hormones And Identify The Major Endocrine Glands And The Hormones They Produce

Question 1

What is a hormone?

Answer 1

Hormones are chemical signals produced in endocrine glands or tissues that travel in the bloodstream to cause an effect on other tissues

Question 2

Name the classification of hormones?

Answer 2

1. Peptide / polypeptide : largest group, short chains of amino acids
   - insulin
   - glucagon
   - growth hormone
   All water soluble
2. Amino acid derivatives (amine) : synthesised from aromatic amino acids
   - adrenaline (tyrosine)
   - noradrenaline (tyrosine)
   - thyroid hormones (tyrosine)
   - melatonin ( tryptophan)
   Adrenal medulla hormones = water soluble
   Thyroid hormones = lipid soluble
3. Glycoproteins : large proteins molecules, often made of subunits and carbohydrates side chain.
   - luteinising hormone
   - follicle stimulating hormone
   - thyroid stimulating hormone
   All water soluble (as they are proteins)
4. Steroids : all derived from cholesterol, steriodgenic tissues convert cholesterol to different hormones
   - cortisol
   - aldosterone
   - testosterone
   All lipid soluble

Question 3

Name the 10 major endocrine glands

Answer 3

1. Hypothalamus
2. Pituitary gland
3. Pineal gland
4. Thyroid gland
5. Parathyroid gland
6. Thymus
7. Adrenal, gland
8. Pancreas
9. Ovary
10. Testes

Question 4

What are the 4 mechanisms of communication via hormones?

Answer 4

Autocrine : hormone signal acts back on the cell of origin

Paracrine: hormone signal carried to adjacent cells over a short distance via interstitial fluid

Endocrine: hormone signal released into blood stream and carried to distant target cells

Neurocrine: hormone originates in neurone and after transport down axon released into blood stream and carried to distant target cells.