Post on 14-Dec-2015
The Central The Central Nervous System Nervous System
PART 5PART 5SPINAL CORD
CNSCNS
Meninges of the Spinal Meninges of the Spinal Cord – same as the brainCord – same as the brain
Dura Mater Dura Mater (HARD MOTHER) (HARD MOTHER) - outer layer, strong white - outer layer, strong white fibrous tissue.fibrous tissue.
Arachnoid membrane Arachnoid membrane (SPIDER WEB) - middle layer, (SPIDER WEB) - middle layer, cobweb like layer.cobweb like layer.
Pia Mater Pia Mater (SOFT MOTHER)-(SOFT MOTHER)-inner layer, adheres to the inner layer, adheres to the brain, translucent. brain, translucent.
The Spinal CordThe Spinal Cord Located within the vertebral column Located within the vertebral column
along with the meninges, CSF, adipose along with the meninges, CSF, adipose tissue and blood vesselstissue and blood vessels
The Spinal CordThe Spinal Cord
-Spinal Cord continues from the medulla oblongata and tapers off at L2 vertebrae (belly button)
-After L2, spinal cord continues as the strands of nerves called the filum terminate and cauda equina.
The Spinal Cord: The Spinal Cord: AnatomyAnatomy
1. Shaped like H, where reflexes are processed
2. Surrounds gray matter, contains tracts to and from the brain.
3. Filled with CSF
Quick CheckQuick Check1.1. Name 4 things found in the vertebral Name 4 things found in the vertebral
column.column.
2.2. At what vertebrae does the spinal cord At what vertebrae does the spinal cord taper off.taper off.
3.3. What are the group of nerves called What are the group of nerves called that come off of the spinal cord after it that come off of the spinal cord after it tapers off?tapers off?
4.4. The center of the spinal cord is made The center of the spinal cord is made of gray matter and shaped like a what?of gray matter and shaped like a what?
The Spinal Cord: The Spinal Cord: AnatomyAnatomy
Ascending Ascending TractsTracts Conduct Conduct
sensory sensory impulses impulses up to up to the brainthe brain
Descending Descending tractstracts Conduct Conduct motor motor
impulsesimpulses down down from the brainfrom the brain
The Spinal Nerve: The Spinal Nerve: AnatomyAnatomy Dorsal nerve rootDorsal nerve root
Carry Carry sensory info sensory info to the spinal cord, (to the spinal cord, (afferent afferent pathwayspathways))
Cell bodies form the dorsal root ganglion before Cell bodies form the dorsal root ganglion before entering the spinal cord.entering the spinal cord.
ThickerThicker Ventral nerve rootVentral nerve root
Carries Carries motor infomotor infoout of spinal cord,out of spinal cord,((efferent pathwaysefferent pathways))
-usually thinner-usually thinner Spinal NerveSpinal Nerve
Dorsal and Ventral root Dorsal and Ventral root Join together to form this Join together to form this Single nerveSingle nerve
The Spinal CordThe Spinal Cord
2. Sensory (Afferent)
1. Sensory Cell Bodies
4. Motor Response (Efferent)
3. Interneuron (Tract)
Spinal Cord InjuriesSpinal Cord InjuriesParalysisHerniated Disk
Quick CheckQuick Check
5.5. What information does the dorsal What information does the dorsal root of the spinal nerve carry?root of the spinal nerve carry?
6.6. What information does the ventral What information does the ventral root of the spinal nerve carry?root of the spinal nerve carry?
7.7. Which root pathway has a ganglion Which root pathway has a ganglion or group of cell bodies?or group of cell bodies?
Reflex—CNS reflexesReflex—CNS reflexes Reflex is a predictable response to a stimulus.Reflex is a predictable response to a stimulus.
It may or may not be conscious.It may or may not be conscious.
Sensory receptor
Sensory neuron
Effector(muscle or gland)
Motor neuron
Interneuron(association) neuron
Reflex ArcReflex Arc
Types of ReflexesTypes of Reflexes
11. . CranialCranial – reflex center located in brain – reflex center located in brain
Ex: corneal reflex - eye blinkEx: corneal reflex - eye blink
2. 2. SomaticSomatic – spinal reflex involving skeletal muscles
Ex: patellar reflex – knee jerk
3. 3. Autonomic – spinal reflex involving – spinal reflex involving smooth or cardiac musclessmooth or cardiac muscles
Ex: heart rate, breathing rate, Ex: heart rate, breathing rate, glands glands
Peripheral Peripheral Nervous System Nervous System
PART 6PART 6Cranial and spinal nerves
PNS
Somatic NS
Autonomic NS
Parasymathetic NSSympathetic NS
“Fight or flight” “Rest and repair”
Voluntary control
Normal stimulation
of involuntary action
Prevents
over-stimulation
of involuntary action
Norepinephrine EpinephrineAcetylcholine
NervesNerves
CranialCranial - come directly off of brain. - come directly off of brain. 12 pairs of nerves that mostly serve the head 12 pairs of nerves that mostly serve the head
and neckand neck
Numbered in order, front to backNumbered in order, front to back
Most are mixed nerves, but three are Most are mixed nerves, but three are sensory onlysensory only
Spinal Spinal – come directly off of spinal – come directly off of spinal cordcord
Slide 7.59Slide 7.59Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 7.21
Cranial NervesCranial Nerves
Spinal Nerve StructureSpinal Nerve Structure
Sympathetic Nervous Sympathetic Nervous SystemSystem
NeurotransmittersNeurotransmitters
Norepinephrine-stimulates normal functioning Norepinephrine-stimulates normal functioning of the smooth and cardiac musclesof the smooth and cardiac muscles
Epinephrine-causes “fight or flight response”Epinephrine-causes “fight or flight response” Increased heart rate and strength of Increased heart rate and strength of
contractioncontraction Dilation of blood vessels in musclesDilation of blood vessels in muscles Constriction of blood vessels in digestive Constriction of blood vessels in digestive
systemsystem Dilated airways and increased respiration Dilated airways and increased respiration
raterate Increased conversion of glycogen to glucoseIncreased conversion of glycogen to glucose
Parasympathetic Nervous Parasympathetic Nervous SystemSystem
NeurotransmitterNeurotransmitter Acetylcholine- reverses the effects of Acetylcholine- reverses the effects of
norepinephrine to maintain norepinephrine to maintain homeostasishomeostasis Slows the heart rateSlows the heart rate Increase rate of peristalsis Increase rate of peristalsis Stimulates digestive and salivary glandsStimulates digestive and salivary glands
Reflex Arc—PNS reflexesReflex Arc—PNS reflexes Reflex can be either muscular or Reflex can be either muscular or
glandular.glandular. It is a predictable response to a particular It is a predictable response to a particular
stimulus.stimulus.Sensory receptor
Sensory neuron
Affector(muscle or gland)
Motor neuron
Interneuron(association) neuron
Reflex ArcReflex Arc
Types of ReflexesTypes of Reflexes
1. 1. StretchStretch – responds to increase load – responds to increase load
Ex: knee reflex (patellar Ex: knee reflex (patellar tendon)tendon)
2. 2. CutaneousCutaneous – responds to touch – responds to touch
Ex: skinEx: skin
3. 3. CranialCranial – involves cranial nerves – involves cranial nerves directly from brain.directly from brain.
Ex: eye blinkEx: eye blink