Autonomic Nervous System 2

What kind of innervation is in vascular smooth muscle?

sympathetic maintains blood pressure

there are un-innervated M receptors in endothelium (when stim cause vasodilation)

What receptor distribution is found in the skin and reservoir veins? What does it cause?

alpha 1

innervated by epi and norepi leading to vasoconstriction

What receptor distribution is found in the skeletal muscle? What does it cause?

alpha 1 - innervated by norepi causing vasoconstriction, high levels epi causes vasoconstriction

beta 2 - low level epi causes vasodilation

What receptor distribution is found in the visceral and renal vasculature? What does it cause?

alpha 1 - norepi and high levels epi of epi or dopamine cause vasoconstriction

beta 2 - low levels epi cause vasodilation

dopamine receptors - low levels dopamine cause vasodilation

What components contribute to stroke volume?

preload - how much blood goes into heart

afterload - pressure heart has to push against

contractility - how hard heart pumping

What contributes to cardiac output?

stroke volume and heart rate

What contributes to mean arterial pressure?

cardiac output and peripheral vascular resistance

How does parasympathetic innervation impact the cardiovascular system?

decreased heart rate due to node innervation

decreased cardiac output

How does sympathetic innervation impact the cardiovascular system?

B1 receptors increase contractility and heart rate increases SV and CO

alpha 1 receptors increase peripheral vascular resistance, B2 decreases resistance (generally increases MAP)

Explain what happens at points A and B

A - HR increases due to B1 receptors

B - vasoconstriction and overall increases pressure

When feeling pulse can you feel an increase in MAP?

not necessarily

when feeling pulse only feeling pulse pressure (difference between systolic and diastolic pressure) MAP can increase while difference between two pressures remain the same

What affects does norepi have on the cardiovascular system?

a1 - increases peripheral vascular resistance

B1 - increases contractilty, HR thus increases SV, CO

increases MAP

Where are baroreceptors found? What do they do?

aortic arch in carotid artery

sense changes in pressure and send impulses to vasomotor complex in medulla

What is the baroreceptor reflex (increased pressure)?

sends impulses to vasomotor complex to decrease sympathetic impuls to arterioles

increases parasympathetic impulses to heart and decreases HR/CO

works in reverse for decreases pressure

How does parasympathetic innervation impact the respiratory system?

Vagus nerve innervates M receptors

bronchoconstriction and mucus secretion

How does sympathetic innervation impact the respiratory system?

B2 receptors stimulates bronchodilation

How does parasympathetic innervation impact the GI system?

facial nerve - stimulates salivary glands

vagus - innervates esophagus, stomach, pancreas, livier, small intestine to relax sphincters, stim GI motility and gastric acid secretion

lumbosacral intumescence - innervates large intestine stimulates GI motility

How does sympathetic innervation impact the GI system?

reduced salivary gland secretion

reduced motility/gastric acid secretion and increased sphincter contraction

increased glycogenolysis and gluconeogenesis

decreased digestive enzyme from acinar cells and increased insulin from islet cells

increased lipolysis

How does pyridostigmine bromide cause intussusception?

blocks AChesterase so ACh concentration goes up and stimulates N_M and N_N receptors to increase intestinal motility

goes to intestine first so has highest concentrations in gut and interacts with ACH junction locally to cause intussusception

How does parasympathetic innervation impact the genitourinary system?

erection

relaxes trigone and induces urinary bladder fundus (stimulates urination)

How does sympathetic innervation impact the genitourinary system?

ejaculation

uterine contraction

increases renin secretion (increases blood pressure)

contracts trigone and relaxes fundus to prevent urination

How does parasympathetic innervation impact the eyes?

increased tear formation by lacrimal/meibomian glands/goblet cells/and 3rd eyelid glands

CN3 - contracts ciliary muscles so lens rounder and accommodate near sight, circular muscles contract causing miosis

open anterior chamber angle to increase aqueous humor outflow and decrease intraocular pressure

How does sympathetic innervation impact the eyes?

alpha receptors - contract radial muscles leading to mydriasis (dilation)

beta - increases aqueous humor production and increases intraocular pressure (closes outflow channel), relaxes ciliary muscle so lens flattens and accommodates distant sight

How does sympathetic innervation impact the spleen?

alpha mediated contraction (PCV increases)

beta2 mediated relaxation

How does sympathetic innervation impact the sweat gland secretion?

cholinergic most species

B2 mediated in horses

How does sympathetic innervation impact the piloerector muscles?

alpha mediated contraction (raises hair)