Autonomic Nervous System

Main function of ANS

Homeostasis

>Maintenance of optimal internal environment

by regulating the activity of viscera, vasculature, and glands.

-Circulation, respiration, digestion, metabolism,

secretions, body temperature

Autonomic functions are _______ and exerted by ________

-unconscious

-exerted by hormones

Internal organs may function of ANS may function ________ of CNS input

Independently

3 different components of ANS

-afferent pathways

-efferent pathways

-central processing

2 diff nervous systems under efferent pathways

-sympathetic nervous system

-parasympathetic nervous system

Types of receptors

-mechanoreceptors

-chemoreceptors

-nociceptors

-thermoreceptors

Mechanoreceptors detect what 2 things

Pressure and stretch

Mechanoreceptors detect pressure of what structures

aorta, carotid arteries, lungs etc.

Mechanoreceptors detect stretch in what structures? What does this mean?

-bladders, and intestines etc.

-Let body know if u need to use restroom

In order to regulate, the ANS requires what to receive different info regarding the body?

Receptors

Chemoreceptors responds to what?

Chemical concentration

Examples of what chemoreceptors detect?

-Carotid and aortic arteries (O2)

-medulla (H+ and CO2)

How do chemoreceptors work? Ex?

-sense oxygen level in the arteries to let brain know whether you need to increase breathing or not to increase oxygen levels (carotid and aortic arteries)

-ex: if CO2 levels in medulla is too high, then receptor will send info to brain to let it know that you need to breathe more frequently

Nociceptors detect what? What structures do they detect this in?

-responds to stimuli of threatened to damaged tissues; responsible for pain information delivery

-Viscera and arteries (ischemia, irritating chemicals)

Nociceptors are also found in?

Hypothalamus

Thermoreceptors are found in what 2 structures? What specifically do they detect in these structures?

-Hypothalamus (body temperature)

-Skin (external temperature)

Afferent pathways carry autonomic info from ______ and enters the _______

From receptors and enters the CNS

What are the 2 different pathways an afferent pathway can send autonomic info?

-the autonomic info goes into the CNS (particularly brain stem area) through cranial nerves.

-autonomic info will be sent in CNS, particularly the spinal cord through the sensory dorsal root. Then info will be further sent to brain stem, hypothalamus and thalamus, etc...

What are the 3 different cranial nerves that convey afferent info?

-cranial nerve VII (facial)

-cranial nerve IX (glossopharangeal)

-cranial nerve X (vagus)

Cranial nerves VII conveys afferent info to and from?

Cranial nerve VII conveys info from tongue and soft palate

Cranial nerve IX will carry afferent info to and from?

Cranial IX which send info from tongue and pharynx

Cranial nerve X will carry afferent info to and from

Cranial X send info from larynx to viscera.

Explain an example of how afferent convey info using the CNS pathway

we have mechanoreceptors and chemoreceptors in aorta; info regarding BP and blood chemical concentration (like oxygen level) will be sent to medulla. Medulla will use info to adjust and control HR and breathing. Info will then be further sent to hypothalamus and thalamus and motivation and emotion area system in the brain, then it will allow those system to modulate the HR and breathing as well.

Central processing is responsible for what 2 things

Autonomic regulation and modulation

What does regulation mean? What 2 structures are control centers for regulation? What do they exactly do?

-regulation=control

-pons and medulla

-control vital functions like HR, respiration, vasoconstric, vasodil

What does modulation mean? What do modulation structures do?

-modulate or change vital function activities

-boss of the pons and medulla (overrides them)

-get a lot of info from a lot of diff places so they can integrate all the signals sent to the brain and make comments to pons and medulla

What is an example of a modulation structure? (Who is the master controller of homeostasis?)

Hypothalamus

What is an example of how a modulation structure work?

medulla and pons get info from mechanoreceptors and mechanoreceptors say that ur current BP and oxygen levels are very good, so u don't need to change HR or breathing frequency. However, emotion system like amygdala also receives info saying that ur ex is showing up in front of you unexpectedly and you become very anxious suddenly, so then ur emotion system will send command to medulla and pons saying that u need to increase HR and breathing so ur brain can have more blood flow and oxygen so u can react better and behave better in front of ex.

Structures for regulation of central regulation and what they do

-Medulla: heart rate, respiration, vasoconstriction, vasodilation

-Pons: respiration

Structures for modulation for central regulation

-Hypothalamus (master controller of homeostasis)

-Thalamus

-Emotion/Motivation System

After info is processed in the in the CNS, the final command needs to be sent out for action, what pathway ones this become? What's the order or pathways?

-Efferent

-afferent>central processing (CNS)>efferent

ANS efferent pathway uses what method?

2 neuron pathway

2 neurons in efferent pathway have synapse located where?

In peripheral ganglion

What is a ganglion

Nerve cell cluster or group of nerve cell bodies

What are the 2 neurons of the two-neuron pathway called and how do they work?

first neuron b4 the ganglion is called preganglionic neuron and sends info from CNS to autonomic ganglion. Then after autonomic ganglion is called postganglionic neuron; and that sends info from autonomic ganglion to target cell.

How do you know when two neuron pathways is considered sympathetic and parasympathetic?

Location and function of the neuron pathway

How do the 2 neurons in the two-neuron pathway communicate with each other?

Through neurotransmitters

All of the preganglionic neurons in the ANS release what regardless if its the sympathetic/parasympathetic system?

ACH

If both the parasympathetic/sympathetic system preganglionic neurons release the same neurotransmitter, how do they differ?

in parasympathetic, post ganglionic release ACH as well but most of the preganglionic neurons in the sympathetic system release norepinephrine/epinephrine.

Thoracolumbar outflow is part of what system?

Sympathetic

Cell bodies of the preganglionic neuron of the thoracolumbar outlflow is located where

Lateral horn of the spinal cord

Why is it called the thoracolumbar outflow?

sympathetic fibers come off the spinal cord at the 12 thoracic levels (T1-T12) and the first two lumbar levels (L1 & L2)

Where does the pre and postganglionic neurons connect in the sympathetic nervous system

Ganglion area

Explain how pre and postganglionic neuron pathway works in sympathetic nervous system

info got sent out from CNS to ganglion through the first preganglionic neuron and then got further sent out from the ganglion to the target cell/organs by the postganglionic neurons.

What is the most important Ian function of the sympathetic nervous system?

maintain optimal blood supply in organs.

Generally speaking, if sympathetic activity increases, then vasoconstriction does what

Increase

Wha is the purpose of vasoconstriction?

allow body to distribute/concentrate blood to certain places that need a lot of blood and decreases blood flow to other areas that may not be that important at the moment so that blood supply of organs will be optimal.

Sympathetic effect of eye

Diameter of pupil will increase bc u need more light into ur eyes to see better

Sympathetic effect on heart

-heart contraction rate and force will increase

-bc muscle needs a lot of blood to function well, so heart will contract more and pump more blood out to muscle

Sympathetic effect on blood vessel of skin

-decrease

-bc blood vessel will constrict to make sure u dont lose heat during fighting or running away. (Decrease heat escaping from skin)

Sympathetic effect on blood vessel of skeletal muscle

-increase

-bc blood vessel will constrict allows blood to stay in the muscles and BP will increase

Sympathetic effect on blood vessel of hear

-increase

-Heart is going to dilate more since it will allow more blood available for the heart to pump it out to the whole body

Sympathetic effect on lungs

-increase in diameter of bronchi and blood vessels

-more oxygen for cells

Sympathetic effect on sweat glands

Production of sweat increases

Sympathetic effect on saliva

-thick secretion will increase

Purpose of thin and thick saliva

-thick: mucus; purpose is for protection of oral cavity

-thin: watery/fluid part; main purpose is for digestion

Norepinephrine/epinephrine of sympathetic nervous system goes to what structures

-Heart

-blood vessels

-bronchi

ACH of parasympathetic nervous system goes to what structures

-glands

-smooth muscles

-heart

-bronchioles

Sympathetic effect on lacrimal gland

-decrease

-vasomotor of blood vessels in contract

Sympathetic effect on adrenal medulla

-increase

-secretion from epinephrine and norepinephrine will increase bc these are fight/flight hormones

-cause increase in HR, muscle strength, BP

Sympathetic effect on GI tract

-decrease

-peristalsis and secretions will decrease bc don't need to digest

Sympathetic effect on liver

-increase

-glucose release will increase; more glucose in blood = more energy in cells

Sympathetic effect on pancreas

-decrease

-secretions will decrease bc pancreatic hormones are for digestion

Sympathetic effect on bowel and bladder

-decrease in emptying

Sympathetic effect on external genitalia

Erection of penis and clit will decrease

Parasympathetic effect on eye

-decrease: diameter of pupil

-increase: curvature of lens to to help u with near vision

Parasympathetic effect on heart

-decrease

-heart contraction rate will decrease

Parasympathetic effect on lungs

-decrease: diameter or bronchi

-increase: secretions of lungs bc resting oxygen needs are not high

Parasympathetic effect on saliva

-increase

-watery saliva will increase for digestion

Parasympathetic effect on lacrimal glands

-increase

-production of tears will increase to moisturize eyes

Parasympathetic effect of sweat glands

Decrease

Parasympathetic effect on GI tract

-increase

-peristalsis and secretions will increase to help with digestion

Parasympathetic effect on adrenal medulla

Secretion of norepinephrine and epinephrine will decrease

Parasympathetic effect on liver

-increase

-glycogen synthesis will increase to help store energy

Parasympathetic effect on pancreas

-increase

-secretions will increase for digestion

Parasympathetic effect on bowel and bladder

-increase

-emptying will increase for digestion

Parasympathetic effect on genitals

Increase