Title: Anatomy and Physiology by Rod R Seeley 6th edition chapter 12 power-point
1 Anatomy and Physiology, Sixth Edition
Rod R. SeeleyIdaho State University Trent D.
StephensIdaho State University Philip
TatePhoenix College
Chapter 12 Lecture Outline
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2Spinal Cord and Spinal Nerves
3Spinal Cord
- Extends from foramen magnum to second lumbar
vertebra - Segmented
- Cervical
- Thoracic
- Lumbar
- Sacral
- Gives rise to 31 pairs of spinal nerves
- Not uniform in diameter throughout length
4Meninges
- Connective tissue membranes surrounding spinal
cord and brain - Dura mater
- Arachnoid mater
- Pia mater
- Spaces
- Epidural Anesthesia injected
- Subdural Serous fluid
- Subarachnoid CSF
5Cross Section of Spinal Cord
6Cross Section of Spinal Cord
- Gray matter
- Neuron cell cell bodies, dendrites, axons
- Horns
- Posterior (dorsal)
- Anterior (ventral)
- Lateral
- Commissures
- Gray Central canal
- White
- White matter
- Myelinated axons forming nerve tracts
- Fissure and sulcus
- Three columns or funiculi
- Ventral
- Dorsal
- Lateral
7Reflex Arc
- Basic functional unit of nervous system and
simplest portion capable of receiving stimulus
and producing response - Components
- Sensory receptor
- Sensory neuron
- Interneurons
- Motor neuron
- Effector organ
8Stretch Reflex
- Muscles contract in response to a stretching
force applied to them
9Golgi Tendon Reflex
- Prevents contracting muscles from applying
excessive tension to tendons
10Withdrawal Reflex
- Function is to remove a body limb or other part
from a painful stimulus
11Withdrawal Reflex with Reciprocal Innervation
- Causes relaxation of extensors muscle when flexor
muscles contract
12Withdrawal Reflex with Crossed Extensor Reflex
- When a withdrawal reflex is initiated in one
lower limb, the crossed extensor reflex causes
extension of opposite lower limb
13Peripheral Nerves
- Consist of
- Axon bundles
- Schwann cells
- Connective tissue
- Endoneurium
- Perineurium Surrounds axon groups to form
fascicles - Epineurium
14Spinal Nerves
15Dermatomal Map
- Skin area supplied with sensory innervation by
spinal nerves
16Cervical Plexus
- C1-C4
- Phrenic nerve
- From C3-C5 cervical and brachial plexus
- Innervate diaphragm
17Brachial Plexus
- C5-T1
- Major nerves
- Axillary
- Radial
- Musculocutaneous
- Ulnar
- Median
18Axillary Nerve
19Radial Nerve
20Musculocutaneous Nerve
21Ulnar Nerve
22Median Nerve
23Lumbosacral Plexus
24Obturator Nerve
25Femoral Nerve
26Tibial Nerve
27Fibular Nerve
28PNS Disorders
- General disorders
- Anesthesia Loss of sensation
- Hyperesthesia Increased sensitivity to pain,
pressure, light - Paresthesia Tingling, prickling, burning
- Neuralgia Nerve inflammation causing stabbing
pain - Sciatica Pain radiating down back of thigh and
leg - Infections
- Herpes Skin lesions
- Shingles or herpes zoster Adult disease of
chickenpox - Poliomyelitis Infantile paralysis
- Genetic and autoimmune disorders
- Myasthenia gravis Results in fatigue and
muscular weakness due to inadequate ACh receptors