Question

1. What are the two classic divisions of the endocrine system?

2. What are some non-classical examples of organs with hormone function?

3. Based on their chemical composition, there are several types of hormones. List the different types and give examples of each.

4. What are pheromones?

Answer 1

Answer 1

Endocrine system can be classified on the basis of:-

I) Location

2) Number

3) Secretion

On the basis of Location:-

Cranial endocrine glands:

These endocrine glands are located in the head region.

e.g., Pituitary gland, Pineal gland, Hypothalamus.

(b) Pharyngeal endocrine glands:

These glands are found in pharyngeal or neck region.

e.g. Thyroid gland, Parathyroid gland.

(c) Abdominal endocrine glands:

These glands are located in the abdominal region.

e.g. Pancreas, Adrenal, Testis, Ovary.

On the basis of Number:-

Unilateral endocrine glands:

These endocrine glands are single in num­ber.

e.g. Pituitary, Pineal gland, Pancreas.

(b) Bilateral endocrine glands:

These endocrine glands are paired in con­dition.

e.g. Thyroid, Adrenal, Parathyroid gland

On the basis of Secretion:-

a) Telecrine glands:

Hormones are re­leased by specialised endocrine cells into the extracellular space and then carried by blood to the dis­tant target cells

e.g. Thyroid gland, Adrenal gland, Pituitary gland etc.

b) Paracrine glands:

Hormones diffuse locally through the interstitial fluid from the secretory cells to the adja­cent target cells.

Answer 2:-

Harmone                       Organ

Leptin                    Adipose Tissue (Fat)

Erythropoietin.            Kidney

Renin.                         Kidney

Calcitriol.                     Skin

Angiotensin.                 Liver

Answer 3:-

i. Amino acid derivatives

Examples:- epinephrine, norepinephrine, dopamine, the thyroid hormones, and melatonin.

ii. Peptide hormones

Examples:- antidiuretic hormone (ADH), oxytocin, Growth Harmone, TSH etc.

iii. Lipid derivatives are of two types

1. Steroid Harmone - testosterone, progesterone

2. Eicosanoids:-leukotrienes and prostaglandins.

Answer 4 :-

PHERMONES:-

pheromone are chemically hormones produced by animals which influence the behavior of another animal of the same species.

They are ectoharmones and acts externally.

Phermones are used for communication in insects. In mammals they are helpful in controlling emotional behaviour.