POWERPOINT ® LECTURE SLIDE PRESENTATION by ZARA OAKES, MS, The University of Texas at Austin Additional text by J Padilla exclusively for Physiology 31.

POWERPOINT® LECTURE SLIDE PRESENTATIONby ZARA OAKES, MS, The University of Texas at AustinAdditional text by J Padilla exclusively for Physiology 31 at ECC

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

HUMAN PHYSIOLOGYAN INTEGRATED APPROACH FOURTH EDITION

DEE UNGLAUB SILVERTHORN

UNIT 2UNIT 2

PART A

11 Efferent Division: Autonomic and Somatic Motor Control


About this Chapter

Autonomic division Antagonistic controls

Somatic motor division CNS control of skeletal muscles through

neuromuscular junctions

****** Review the overall organization of the NS


Autonomic Division: Homeostasis

Antagonistic branches Parasympathetic

“Rest and digest”

Restore body function

Sympathetic

“Fight or flight”

Energetic action


Autonomic Division: Homeostasis

Figure 11-1

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 11-2

Autonomic Pathways

Coordination of homeostatic responses Autonomic

Endocrine

Behavioral


Autonomic Control Centers

Hypothalamus Water balance,

temperature, and hunger

Pons Respiration,

cardiac, and urinary

Medulla Respiration

Figure 11-3


Two Efferent Neurons in Series

Autonomic pathways

Figure 11-4


Two Efferent Neurons in Series

CNS- tracts coming from brain to spinal cord

Preganglionic neuron- exits spinal cord and goes to ganglion

Ganglion- sympathetic chain ganglion runs along vertebral colum

Postganglionic neuron- runs down spinal nerve

Target tissue- can be muscle or gland


Sympathetic versus Parasympathetic

Figure 11-7

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 11-5

Antagonistic Control

Autonomic sympathetic and parasympathetic pathways

Notice the mention of antagonistic responses & receptors involved

Notice the mention of antagonistic responses & receptors involved


Sympathetic vs Parasympathetic


III. Nerves- these are bundles of axons (nerve fibers) that are myelinated or unmyelinated. Each axon is surrounded by an endoneurium, groups of nerves are bundles into nerve fascicles surrounded by perineurium and the whole nerve is surrounded by epineurium. *Know the difference between neuron, nerve fiber, and nerve.

Nerves are found in the PNSNerves are found in the PNS



Spinal cord exit

Neurotransmitters

Receptors




Autonomic Targets

Smooth muscle

Cardiac muscle

Exocrine glands

Endocrine glands

Lymphoid tissue

Adipose tissue


Autonomic Neuron Structure Neuroeffector junction -

synapse between a postganglionic autonomic neuron and target cell

Postganglionic axon - exits spinal cord to target cell Varicosities - instead of axon

terminals, there are multiple branches and varicosities along the axon over the surface of the target cell


Synapses in Autonomic Neurons

Neurotransmitter released to ECF

No synaptic cleft

Impact Large area

Slow acting

Long duration


Review of Efferent Pathways

Summary of the efferent pathways of the peripheral nervous system

Figure 11-11

ACh

Somatic motorpathway

Parasympatheticpathway

GanglionNicotinicreceptor

Nicotinicreceptor

CNSCNS

AUTONOMIC PATHWAYS

ACh

CNSCNS

Adrenal medulla

Adrenal cortex

E

Sympatheticpathways

GangliaAch = acetylcholineE = epinephrineNE = norepinephrine

1 receptor

2

receptor

Blood vessel

E

Autonomic effectors:•Smooth and cardiac muscles•Some endocrine and exocrine glands

•Some adipose tissue

KEY

receptor

Skeletalmuscle

ACh

Muscarinicreceptor

Nicotinic receptorACh

NE

Adrenal sympathetic pathway



Figure 11-11 (1 of 5)


CNS

Ach = acetylcholineE = epinephrineNE = norepinephrine

KEY

Skeletalmuscle




Figure 11-11 (2 of 5)

ACh




CNSCNS

AUTONOMIC PATHWAYS

Ach = acetylcholineE = epinephrineNE = norepinephrine



KEY

Skeletalmuscle

ACh

Muscarinicreceptor




Figure 11-11 (3 of 5)

ACh




Nicotinicreceptor

CNSCNS

AUTONOMIC PATHWAYS

ACh

CNS

Sympatheticpathways




KEY

receptor

Skeletalmuscle

ACh

Muscarinicreceptor


NE



Figure 11-11 (4 of 5)

ACh




Nicotinicreceptor

CNSCNS

AUTONOMIC PATHWAYS

ACh

CNS

Sympatheticpathways


1 receptorAutonomic effectors:

•Smooth and cardiac muscles•Some endocrine and exocrine glands


KEY

receptor

Skeletalmuscle

ACh

Muscarinicreceptor


NE



Figure 11-11 (5 of 5)

ACh




Nicotinicreceptor

CNSCNS

AUTONOMIC PATHWAYS

ACh

CNSCNS

Adrenal medulla

Adrenal cortex

E

Sympatheticpathways


1 receptor

2

receptor

Blood vessel

E



KEY

receptor

Skeletalmuscle

ACh

Muscarinicreceptor


NE

Adrenal sympathetic pathway




Visceral sensory neurons- Receptors in the viscera are free dendritic ends that send afferent signals caused by stretching, temperature and chemical changes, and irritation. Integration translates these signals into hunger, fullness, pain, or nausea. Visceral sensation may be hard to localize. Sometimes pain is called referred pain. A problem with an organ like the heart may send pain down the arm (not an area where the heart is located.)

A map of referred pain: these are skin or body regions that present pain when there is visceral pain. The organ and site of referred pain are innervated by the same nerve.

Referred Pain- Visceral Sensory DivisionReferred Pain- Visceral Sensory Division


Somatic Motor Division

Skeletal muscle- target effector

Body movement- main function, voluntary or a reflex

Appendages- fine and gross motor skills

Locomotion- movement of body at different speeds


Somatic Motor Division

Single neuron CNS origin

Myelinated

Terminus Branches

Neuromuscular junction

Figure 11-11 (1 of 4)


Neuromuscular Junction: Overview

Terminal boutons- insulate the site of the neuromuscular juction and secrete supportive growth factors

Synaptic cleft- space between the axon terminal and the sarcolemma Acetylcholine- neurotransmitter released involves

calcium and binds to nicotinic receptors

Motor end plate- folds on the sarcolemma of the muscle On muscle cell surface

Nicotinic receptors

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 11-12 (1 of 3)

Anatomy of the Neuromuscular Junction



Figure 11-12 (2 of 3)



Figure 11-12 (3 of 3)


Mechanism of Signal Conduction

Axon terminal (of presynaptic cell) Action potential signals acetylcholine release

Motor end plate – series of folds in the plasma membrane of the postsynaptic cell Two acetylcholine bind

Opens cation channel

Na+ influx – K+ efflux

Membrane depolarized

Stimulates fiber contraction as a result in increased intracellular calcium concentration

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 11-13a

Events at the Neuromuscular Junction

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Figure 11-13b

Events at the Neuromuscular Junction

Notice that both Na and K use the same channel unlike those of neuronsNotice that both Na and K use the same channel unlike those of neurons


Somatic and Autonomic Divisions


Summary

Autonomic division Role in homeostasis

Sympathetic and parasympathetic branches

Regulate glands, smooth and cardiac muscles

CNS control centers

Antagonistic regulation


Summary

Somatic division Efferent motor neurons control skeletal muscles

Single long myelinated neuron from CNS

Neuromuscular junction structure and mechanism

POWERPOINT ® LECTURE SLIDE PRESENTATION by ZARA OAKES, MS, The University of Texas at Austin Additional text by J Padilla exclusively for Physiology 31.

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