Question

what will happen when you loose a lot of blood (hemorrhage)

1. signal to NTS increase

2. veins smooth muscle contraction goes up

3. vasodilation

4. increased stimulation of SA node

5. nothing

Answer 1

Ans:- b) veins smooth muscle contraction goes up. Is true

Because when there is haemmorage then mean arterial pressure decrease so to compensate for that smooth muscles of vein are contracted by sympathetic system.

1) Signal to nucleus tractus sollitorius decreases.

When there is increase mean arterial pressure then signal to NTS is increased . Which generally inhibit sympathetic nervous system and stimulate parasympathetic nervous system .

But in case of haemmorage this signal is decreaeased leading to opposite effect.

Concept:- NTS Is connected to BARORECEPTORS of carotid sinus and arotic sinus . And help to maintain constant blood pressure.

The carotid sinus baroreceptors are innervated by the sinus nerve of Hering, which is a branch of the glossopharyngeal nerve (IX cranial nerve). The glossopharyngeal nerve synapses in the nucleus tractus solitarius (NTS) located in the medulla of the brainstem. The aortic arch baroreceptors are innervated by the aortic nerve, which then combines with the vagus nerve (cranial nerve X) traveling to the NTS. The NTS modulates the activity of sympathetic and parasympathetic (vagal) neurons in the medulla, which in turn regulate the autonomic control of the heart and blood vessels.