Nervous System IV Somatic Sensory Reflexes Neural Integration

Nervous System: IV Somatic Sensory Reflexes Neural Integration ANS

Nervous System Design n Sensory Receptors in PNS q q n CNS q q q n Somatic: Tactile, Nocireceptors, Proprioceptors, Baroreceptors Special: Photoreceptors, Mechanoreceptors, Chemoreceptors Spinal Cord Brainstem Cerebellum Thalamus Cerebral Cortex Motor Effectors q q Somatic Motor Autonomic Motor

Sensory Overview

CN: Special and Somatic Sensory

Somatic Sensory: Skin

Somatic Sensory: Proprioception

Dermatomes

Stretch Receptors

Golgi Tendon Organ

Intrafusal Fibers

Somatic Reflex Arc

Motor Response Neuromuscular Junction

Motor End Plate

Patellar Reflex: Monosynaptic

Polysynaptic Reflexes

Somatic Reflex Tests

Spinal Cord and Spinal Nerves

PNS CNS for somatic sensory

Spinal Cord Gray and White Matter

Spinal Cord Histology Areas

Spinal Tract Names

Organization of Spinal Cord Segment

Spinal Tract Locations

Ascending Tracts: Specific n Dorsal Column – Medial Lemniscus q q q Localized touch Gradations of touch Vibratory sensations Proprioception Pressure sensations n Fasciculus Cunneatus q q q n Upper Limbs Upper Trunk Neck Fasciculus Gracilis q q Lower limbs Inferior trunk

Ascending Tracts

Dorsal White Columns

Ascending Tracts: Nonspecific n Anterolateral System q q q Pain Temperature Crude touch Crude pressure Tickle / Itch Sexual sensations n Spinothalamic tract q Lateral n n q Pain Temperature Anterior n n Crude Touch Crude Pressure

Spinothalamic Tracts

Localization of information: Spinal Nerve Input to Spinothalamic tract

Spinocerebellar Pathways n Posterior Cerebellar q q q n Trunk, lower limb proprioceptors Tendon stretch Ascend on same side to inferior cerebellar peduncle Anterior Cerebellar q q q Trunk, lower limb proprioceptors Tendon stretch Ascend and cross twice to anterior cerebellar peduncle

Spinocerebellar Tracts

Somatosensory Reflexes

Descending Motor Tracts n Direct / Pyramidal q q Skeletal voluntary motor Corticobulbar n q CN motor Corticospinal n Indirect / Extrapyramidal q q q n q q Muscle tone to extensors Posture and balance Rubrospinal n Cross in spinal cord Coordinate reflexes to visual and auditory stimulus Vestibulospinal n Cross in medulla Anterior Tectospinal n Lateral q n n Muscle tone to flexors Reticulospinal (A, M, L) n n n Visceral motor tone Visceral motor functions Visceral reflexes

Descending Motor Tract Locations

Ventral White Matter Ventral White Axons leaving Gray Matter

Descending Motor Tract Functions

Corticospinal Tract Location

Corticospinal General Descending Pathway

Descending Somatic Pathway

Extra Pyramidal Tracts

Motor Tracts Compared

Basal Nuclei n Adjust movement q q n Rhythmic Cycles q q n Preparation Coordinate Subconscious control Alter motor commands Communication q In n n q Caudate Putamen Out n n Globus Pallidus Thalamus

Basal Nuclei Afferents Caudate and Putamen

Basal Nuclei Efferents Globus pallidus to Thalamus

Basal Nuclei Regulation Summary

Thalamic Nuclei: Ventrolateral Group

Thalamus: Ventral Group

Thalamus: Dorsolateral

Thalamus: Dorsomedial Group

Thalamus: Anterior Group

Thalamus: Pulvinar

Thalamus: Geniculates Medial Geniculate Lateral Geniculate

Problems

Spinal Nerve Rupture

Spinal Cord Tracts and related problems

Nervous System Organization: ANS

CNS and PNS for ANS

Somatic vs. Autonomic

Spinal Nerve Review

Pathways and Reflexes Compared for SNS and ANS

Lateral Gray Horn of Spinal Cord

ANS Divisions

Origins for Preganglionic ANS neurons

Postganglionic Neuron Pathways

Myelination vs Nonmyelination

ANS Motor

Preganglionic ANS neurons

Neuron Organization : Preganglionic Neurons, NT, and Receptors

Sympathetic NS

Lateral Gray Matter: ANS sensory and motor for Sympathetic Division

Sympathetic Chain

Sympathetic Chain Ganglia in cat

Sympathetic Chain Pathways

Thoracic Cord: Gray and White Ramus

Sympathetic Collateral Ganglia

Sympathetic Ganglion

Adrenal Medulla

Rami Communicans and Sympathetic Pathways

Ganglia Location

Parasympathetic NS

Parasympathetic Cranio-Sacral

Parasympathetic Ganglia

Parasympathetic Nerves n Cranio q q n CN III CN VII CN IX CN X Sacral q Splanchnic N.

CN X

CN X Motor pathways

CN X: Innervation

CN X: Sensory Inputs and Pathways

Synapse and Varicosities

ANS Neurotransmitters

ANS neurotransmitter receptors

Nicotinic Receptors Receptor Location Effect Nicotinic ganglionic ANS ganglions Excitatory ANS postganglionic neurons Nicotinic Neuromuscular Junction Excitatory Skeletal m.

Muscarinic Receptors Receptor Location Effect Muscarinic M 1 Sympathetic Postganglionics Muscarinic M 2 Heart, Eye, GI, UG, Respiratory Ach Inhibit NE Relaxation of vascular Sm M. Inhibitory c. AMP K+ influx Muscarinic M 3 Vascular: dilation PIP DAG, IP 3 Exocrine Gland secretion

Catecholamine Receptors: Alpha Receptors Location Effects Alpha 1 IP 3/DAG Constriction of Vascular Sm. M & Ca++ GI sphincters Pupillary dilation Alpha 2 Inhibits post ganglionic Gi inhibit c. AMP

Catecholamine Receptors: Beta Receptors Location Effects Beta 1 excitatory Heart, brain, kidney Adenyl Cyclase c. AMP Beta 2 Inhibits Vascular Adenyl Cyclase c. AMP & Respiratory Sm M Excites Islet B Beta 3 Adipose c. AMP

Parasympathetic Pathway Review

Cholenergic Neurotransmitters

ACh formation and recycling

Sympathetic Pathway Review

Adrenergic Neurotransmitters

Adrenergic Synapse

NT hydrolysis from Tyrosine

Enzymes in Catecholamine Formation

Catecholamine Breakdown n Uptake I q Reuptake of NE into presynaptic neuron n n Monoamine Oxidase (MAO) breakdown Uptake II q Reuptake of NE into non-neuronal cells n Catechol-O-Methyltransferase (COMT) breakdown q q n n Glial cells Smooth Muscle Metabolites diffuse out MAO completes breakdown

NE

MAO Blocker

Chemicals in ANS n Neurotransmitters q q q q ACh NE ATP VIP Dopamine Metenkephalin Neuropeptide-Y n Hormones q q Epinephrine Prostaglandins

Visceral Reflex Arc

ANS Referred Pain reflexes

Lateral Spinothalamic Pathway: Pain

Ascending Spinal Cord Tracts for ANS

Thalamic VPL input from Spinothalamic

Sensory Homonculus

Referred Pain

ANS Controls

ANS pathways for Hypothalamic Control

Medulla Oblongata Controls

ANS tests

Generalized ANS effects

Dual Innvervation

Dual Innervation Example

Dual Innervation: Salivary Glands

ANS drugs

Clinical ANS Applications

Questions?