Question

What division of the nervous system is very active in people involved in stressful situations? What reactions does the body have to stress because of this branch of the nervous system? Briefly discuss how the endocrine system works with the nervous system in stress?

Answer 1

Hypothalamus directs the body's stress response.The nervous system sends input about the stress condition to the hypothalamus, which engages both the nercous system and endocrine system to cope up with the environment.The hypothalamus can provide signal to the spinal cord via sympathetic activity and directly to the adrenal gland through the pituitary gland to secrete epinephrine.There are 2 types of response:

1.Sympathetic nervous system is a branch of autonomous nervous system that comes into action during the stress conditions-' Fight & flight response'.This makes the body adapted to the stress situations by coordinating with the endocrine system.

• Increased heart rate in order to pump more oxygen and nutrient to the tissues
• Increased respiration rate to accomodate more oxygen into the blood and further to the tissues and more carbon dioxide is formed as the waste product of the cellular respiration in the muscle tissues.
• Change in blood pressure
• Redirection of blood flow to the skeletal muscles.
• sweating
• Increased peripheral vasoconstriction. The blood vessels of the extremities are congested in order to provide more oxygen and nutrients to the core areas like heart and brain.

2.Endocrine system cotribute to the hormonal activity of the stress situation by releasing two important catecholamine hormones -Epinephrine and norepinephrine(produced from the adrenal gland medulla).These hormones act as major communicators in the sympathetic response.The hypothalamus sends the signal to the adrenal medulla through ANS to produce epinephrine.(AUTONOMOUS NERVOUS SYSTEM)

The hypothalamus secretes the corticotropic releasing hormone to pituitary, which in turn secrete ACTH to the adrenal cortex.Cortex of the adrenal gland produces another type of stress hormones called glucocorticoids manily cortisol as a response to the corticotropic hormone from pituitary (ENDOCRINE SYSTEM).The cortisol plays a major role by redistributing the glucose to the tissues and suppressing the immune system.

• Mobilization of energy
• Enhance the sympathetic response
• mobilize carbohydrates
• provides more glucose by breaking down the fat.
• Converting glycogen into glucose
• supply blood with lot of glucose.
• Release of amino acids by the skeletal muscle to repair the damaged tissue.
• suppression of immune response
• vasoconstriction of blood vessels in the digestive system.

Mineralocorticoids:

• retention of sodium and water by kidneys
• Increase blood volume and blood pressure.

Glucocorticoid:

• Fats and proteins are converted into glucose to make more energy
• Increases blood glucose level and suppresses immune system

Epinephrine/Norepinephrine:

1. Glycogen breakdown to glucose
2. Increased blood pressure
3. increased breathing rate
4. Increased metabolic rate
5. change in blood flow pattern
6. decrease digestive and kidney activities.