Lecture 2 The Autonomic Nervous System James B. Parker Ph.D. Physiology 1 Lecture Outline 2 Lecture Outline 2

Lecture 2 Lecture 2 The Autonomic Nervous The Autonomic Nervous

SystemSystemJames B. Parker Ph.D.James B. Parker Ph.D.

Physiology 1Physiology 1

Lecture Outline 2Lecture Outline 2

The Autonomic Nervous The Autonomic Nervous SystemSystem

OBJECTIVES:OBJECTIVES: 1. The student should be able to define the 1. The student should be able to define the

organization and function of the autonomic organization and function of the autonomic nervous system (ANS).nervous system (ANS).

2. The student should be able to define the 2. The student should be able to define the effects of the ANS.effects of the ANS.

3. The student should be able to list the 3. The student should be able to list the receptors and neurotransmitters of the ANS.receptors and neurotransmitters of the ANS.

4. The student should be able to list the 4. The student should be able to list the sympathetic stress response.sympathetic stress response.

ANS OrganizationANS Organization

The ANS affects visceral function and The ANS affects visceral function and chiropractic affects the ANS, therefore, chiropractic affects the ANS, therefore, chiropractic affects visceral functionchiropractic affects visceral function

How then is the ANS organized?How then is the ANS organized? A. HypothalamusA. Hypothalamus B. Brain StemB. Brain Stem C. Spinal CordC. Spinal Cord D. Visceral ReflexesD. Visceral Reflexes



E. Sympathetic Nervous SystemE. Sympathetic Nervous System– 1. Paravertebral sympathetic chains of 1. Paravertebral sympathetic chains of

gangliaganglia– 2. Prevertebral ganglia2. Prevertebral ganglia

a. Celiaca. Celiac b. Hypogastricb. Hypogastric

– 3. T-1 to L-23. T-1 to L-2


F. Parasympathetic Nervous SystemF. Parasympathetic Nervous System - Craniosacral Division- Craniosacral Division G. Tissues Regulated - Involuntary OrgansG. Tissues Regulated - Involuntary Organs

– 1. Visceral (Hollow) Organs1. Visceral (Hollow) Organs– 2. Exocrine Glands2. Exocrine Glands– 3. Endocrine glands3. Endocrine glands– 4. Blood Vessels4. Blood Vessels– 5. Heart5. Heart


H. Cell TypesH. Cell Types– 1. Smooth Muscle1. Smooth Muscle– 2. Cardiac Muscle2. Cardiac Muscle– 3. Gland Cells3. Gland Cells

I. FunctionsI. Functions– 1. Homeostatic conditions in the body1. Homeostatic conditions in the body– 2. Coordinating body response to stress2. Coordinating body response to stress– 3. Assist endocrine system reproduction3. Assist endocrine system reproduction

Sympathetic Nervous Sympathetic Nervous SystemSystem

A. Thoracolumbar DivisionA. Thoracolumbar Division B. Preganglionic Neuron - generally B. Preganglionic Neuron - generally

short axon in spinal columnshort axon in spinal column– 1. Cell body in intermediolateral 1. Cell body in intermediolateral

hornhorn– 2. Fibers pass through anterior 2. Fibers pass through anterior

hornhorn


– 3. Synapse3. Synapse a. In immediate ganglia (near a. In immediate ganglia (near spinal cord)spinal cord)

b. Pass upward or downward b. Pass upward or downward to another gangliato another ganglia

c. On organc. On organ


–4. 3 major central ganglia4. 3 major central ganglia a. Celiac ganglia (solar a. Celiac ganglia (solar plexus)plexus)

b. Superior mesenteric b. Superior mesenteric gangliaganglia

c. Inferior mesenteric c. Inferior mesenteric gangliaganglia


C. Postganglionic NeuronC. Postganglionic Neuron–1. Originate in the 1. Originate in the sympathetic chain ganglia or sympathetic chain ganglia or in one of the prevertebral in one of the prevertebral gangliaganglia


– 2. Destinations2. Destinations a. Skeletal Nerves (about 8% are a. Skeletal Nerves (about 8% are sympathetic)sympathetic)–1. Blood vessels (some are 1. Blood vessels (some are cholinergic)cholinergic)

–2. Sweat glands (cholinergic)2. Sweat glands (cholinergic)–3. Piloerector muscles of the 3. Piloerector muscles of the hairs (cholinergic)hairs (cholinergic)


b.b. Segmental distribution of sympathetic Segmental distribution of sympathetic nerves – T1 and T2 head and neck, T3-nerves – T1 and T2 head and neck, T3-T6 thorax, T7-T11 abdomen, T12-L2 legsT6 thorax, T7-T11 abdomen, T12-L2 legs

c.c. c. Adrenal medullae c. Adrenal medullae – 1. Medullar secretes epinephrine and 1. Medullar secretes epinephrine and

norepinephrine into the blood streamnorepinephrine into the blood stream– 2. Fight or flight response2. Fight or flight response

a. Capable of firing all at once in a a. Capable of firing all at once in a coordinated fashioncoordinated fashion

b. Generalized sympathetic b. Generalized sympathetic responseresponse


D. FunctionsD. Functions– 1. Emergency responses1. Emergency responses– 2. Utilization of resources 2. Utilization of resources

(Redistribution)(Redistribution)

Parasympathetic Nervous Parasympathetic Nervous SystemSystem

A. Cranial-sacral DivisionA. Cranial-sacral Division– 1. Cranial nerves III, VII, IX, X1. Cranial nerves III, VII, IX, X– 2. 2nd & 3rd sacral spinal 2. 2nd & 3rd sacral spinal

nerves (Sometimes 1st & 4th)nerves (Sometimes 1st & 4th) B. 75% are in the vagus nerve (X)B. 75% are in the vagus nerve (X) C. Preganglionic fibers generally C. Preganglionic fibers generally

synapse at site of organsynapse at site of organ

Parasympathetic Nervous Parasympathetic Nervous SystemSystem

D. Cholinergic-acetylcholine like D. Cholinergic-acetylcholine like actionsactions– 1. Restoration and buildup of 1. Restoration and buildup of

body reservesbody reserves– 2. Elimination of waste2. Elimination of waste– 3. Digestion and absorption of 3. Digestion and absorption of

foodfood– 4. Rest and relaxation4. Rest and relaxation

NeurotransmittersNeurotransmitters

A. Acetylcholine (Parasympathetic A. Acetylcholine (Parasympathetic nervous transmitter)nervous transmitter)– 1. Secreted by cholinergic fibers1. Secreted by cholinergic fibers– 2. All preganglionic neurons2. All preganglionic neurons– 3. All (almost) parasympathetic 3. All (almost) parasympathetic

postganglionic neurons (some postganglionic neurons (some release GABA a neural inhibitor)release GABA a neural inhibitor)

NeurotransmittersNeurotransmitters

B. Norepinephrine (Sympathetic B. Norepinephrine (Sympathetic transmitter)transmitter)– 1. Secreted by adrenergic fibers1. Secreted by adrenergic fibers– 2. All postganglionic neurons except, 2. All postganglionic neurons except,

preganglionic fibers are cholinergic preganglionic fibers are cholinergic (Ach)(Ach) a. Sweat glands (Ach)a. Sweat glands (Ach) b. Piloerector muscle (Ach)b. Piloerector muscle (Ach) c. Some blood vessels(Ach)c. Some blood vessels(Ach)

ReceptorsReceptors

A. Acetylcholine receptors (Ach is A. Acetylcholine receptors (Ach is the most prevalent the most prevalent neurotransmitter in the peripheral neurotransmitter in the peripheral nervous system)nervous system)– 1. Muscarinic Receptors1. Muscarinic Receptors

a. Activated by the fungus a. Activated by the fungus muscarinemuscarine

b. Found in the effector cells b. Found in the effector cells

ReceptorsReceptors

– 2. Nicotinic Receptors2. Nicotinic Receptors a. Found in the synapse a. Found in the synapse between the preganglionic and between the preganglionic and postganglionic neurons of both postganglionic neurons of both the sympathetic and the sympathetic and parasympathetic systems and parasympathetic systems and Skeletal muscle fibersSkeletal muscle fibers

ReceptorsReceptors

B. Adrenergic ReceptorsB. Adrenergic Receptors– 1. Alpha receptors1. Alpha receptors

a. Alpha1a. Alpha1 b. Alpha2b. Alpha2 c. Excited by Norepinephrine c. Excited by Norepinephrine & Epinephrine& Epinephrine

ReceptorsReceptors

– 2. Beta Receptors2. Beta Receptors a. Beta1a. Beta1 b. Beta2b. Beta2 c. Excited primarily by c. Excited primarily by epinephrineepinephrine

Effects of Sympathetic & Effects of Sympathetic & Parasympathetic Parasympathetic

StimulationStimulation

SYM PSYMSYM PSYM EyesEyes Pupil dilationPupil dilation Pupil Constriction Pupil Constriction GlandsGlands Increased Increased Increased nasal, Increased nasal,

Sweating Sweating salivary, and GI secretions salivary, and GI secretions GIGI decreaseddecreased Increased GI Increased GI

activityactivity– activityactivity

HeartHeart IncreasedIncreased decreased decreased activityactivity

– activityactivity

Stress Response - Stress Response - Sympathetic Nervous Sympathetic Nervous

SystemSystem

A. Fight or flight responseA. Fight or flight response B. Mass sympathetic dischargeB. Mass sympathetic discharge C. Stimulation of adrenal medulla - C. Stimulation of adrenal medulla -

(epinephrine release)(epinephrine release)– 1. Catacholamine1. Catacholamine– 2. All effects have adrenergic receptors2. All effects have adrenergic receptors– 3. From adrenal medulla chromaffin cells3. From adrenal medulla chromaffin cells– 4. Enhances mobilization of glucose and fatty 4. Enhances mobilization of glucose and fatty

acids, blood clotting and distribution, immune and acids, blood clotting and distribution, immune and tissue responses to injurytissue responses to injury

Stress Response - Stress Response - Sympathetic Nervous Sympathetic Nervous

SystemSystem

D. ResponseD. Response– 1. Increased arterial pressure1. Increased arterial pressure– 2. Increased blood flow2. Increased blood flow– 3. Shunting of blood to active sites3. Shunting of blood to active sites– 4. Increased cell metabolism4. Increased cell metabolism– 5. Increased blood glucose concentration5. Increased blood glucose concentration– 6. Increased glycolysis in liver6. Increased glycolysis in liver– 7. Increased muscle strength7. Increased muscle strength– 8. Increased mental activity8. Increased mental activity– 9. Increased rate of blood coagulation9. Increased rate of blood coagulation

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Lecture 2 The Autonomic Nervous System James B. Parker Ph.D. Physiology 1 Lecture Outline 2 Lecture Outline 2