3. ANS lecture Flashcards
What happens to the heart during sympathetic stimulation?
B1 and B2 receptors on the ventricles are activated and result in increased contraction of the heart muscle via increased cAMP production which will increase the amount of calcium that is present for the heart to contract
What happens to the arteries during sympathetic stimulation?
some arteries have both alpha and beta receptors so that the brain can decide what needs to be turned on and receive blood and others just have alpha receptors, which will decrease the amount of blood to those areas
What are the arteries that have both alpha and beta receptors?
Coronary skeletal muscle Pulmonary Abdominal viscera Renal arteries
What happens to the veins if the sympathetic system is stimulated?
Alpha 1 and 2 receptors are activated which causes constriction of the muscle, increasing the venous pressure and blood return to the heart
B2 receptors are also activated to prevent back pressure of the blood flow and keep everything moving as it should be
What is the effect of the sympathetic stimulus on the respiratory system?
B2 receptors allow for the airways to relax and make breathing easier
alpha 1 receptors are activated to decrease secretions which will also make breathing easier
If this decrease in secretions is too hardcore and irritating for the system, then there will be B2 receptors that can help to increase the secretions if needed to keep everything moist
What happens to the eyes during sympathetic stimulation
Radial muscles of the iris are contracted and the ciliary muscles of the lens are relaxed
Describe the effect that the radial muscles of the iris have on the eye
Can constrict and dilate the pupils to let more light in (alpa adrenergic)
In the event of a sympathetic stimulus, there will be an increased amount of light coming into the eye so that you can see the predator, this will result in dilation
Describe the ciliary muscles of the lens during sympathetic stimulation
The B2 receptors are activated which causes relaxation of the muscle, which allows the lens to be flattened which will allow vision at farther distances
Describe what happens in the stomach and the intestines during sympathetic stimulation
There are alpha 2 receptors that will decrease secretion of the stomach; you are not going to digest a lot
Why do you get dry mouth as a result of being nervous?
The alpha 1 receptors cause a thick secretion and the B receptors cause an increase in amylase which also thickens secretions, which will decrease the amount of saliva that is in the mouth
Describe what the various cells of the pancreas do during sympathetic stimulation?
a1 cells: decrease GI enzymes
a2 cells: decrease insulin and glucagon
B2 cells: increase insulin and glucagon
How do the receptors in the bladder work in sympathetic stimulation in order to make sure that you do not pee?
The B2 receptors relax the detrusor muscle, which will not let you know you have to pee
The alpha 1 receptors cause the sphincters to contract, and do not let anything out
Describe the skin during sympathetic stimulation
Alpha 1 receptors on pili erector muscles contract
sweat glands have alpha one receptors that result in light sweating
What are the overall clinical sx of sympathetic stimulation
Increased heart rate and contractility due to an increase B1 and B2 receptors
Ease of breathing due to decreased secretions and the B2 receptors relaxing the airway
decreased GI stuff; no digesting
Eyes will be dilated and the lens will be flattened to increase the visual field
Glucose will be broken down in the liver
What happens in the liver in the event of sympathetic stimulation?
Alpha 1 and B2 cells are going to increase the amount of glucose
