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Central Nervous System (CNS)
• brainbrain
• spinal cordspinal cord
Peripheral Nervous System (PNS)
• cranial nervescranial nerves
• spinal nervesspinal nerves
CNS PNS
sensory receptor
sensory input
integration
motor input
effector
cell body
dendrite
SynapseaxonMyelin sheath
bipolareye, ear, & olfactory Unipolar
Dorsal root ganglion cells
multipolarmost abundant type in CNS
Dendrite
Na+
K+
Outside cell
-70mV
Inside cell
Presynaptic neuron
Postsynaptic membrane
Ca2+
Synaptic vesicles containing neurotransmitters
• Acetylcholine- slows heart rate; PNS • Glutamate- most prevalent neurotransmitter in the brain• Aspartate- in CNS• GABA- inhibitory neurotransmitter• Glycine- inhibitory neurotransmitter• Norepinephrine- awakening from deep sleep• Epinephrine- increase heart rate• Dopamine- movement of skeletal muscles• Seratonin- sensory perception, temp regulation, mood,
sleep• Nitric oxide- may play a role in memory and learning• Enkephalin- inhibit pain impulses by suppressing release
of substance P• Substance P- enhances perception of pain
tyrosine
Coverings of the Brain-Coverings of the Brain- MeningesMeninges
skin
skull
dura mater
arachnoid layer
pia mater
cerebral cortex
Menenges:
1.Covers and protects CNS
2.Protects blood vessels and
encloses venus sinuses
3.Contains CSF
4.Forms partition within the skull
Cerebruspinal Fluid
Brain
Ventricles
CSF
Spinal Cord
Anterior View Saggital View
Rt. Ventricle Lf. Ventricle
CSF • 150 ml in adult• contains: glucose, proteins,lactic acid,
urea, cations, anions, WBC Functions:
1.Reduces wt. of brain by 97%2.Prevents head injury3.Supplies brain with nutrition4.Transports hormones along
ventricular channels
CerebrumCerebrumParietal Lobe
Frontal Lobe
Occipital Lobe
Temporal Lobe
cerebrumcorpus callosum
thalamus
cerebellum
medulla
oblongata
hypothalamus
pituitary
pons
spinal cord
Pineal gland
mid brain
CerebrumCerebrum
Involved with higher brain functions.Involved with higher brain functions. Processes sensory information.Processes sensory information. Initiates motor functions.Initiates motor functions. Integrates information.Integrates information.
Motor, Sensory & Association CortexMotor, Sensory & Association Cortex
Primary motor cortex Primary somatosensory cortex
smellhearing
vision
speech taste
reading
speech
Premotor cortex
Broca’s Area
Primary Auditory cortex
Primary visual cortex
Wernicke’s Area
Frontal association area
Fig. 49-17Fig. 49-17
Generating words
Max
Speaking words
Hearing words
Seeing words
Min
Primary Sensory Cortex
Primary Sensory Cortex
Primary Motor CortexPrimary Motor Cortex
Right-Left Specialization of Right-Left Specialization of the Cerebrumthe Cerebrum
left sideleft side• language developmentlanguage development• mathematical & learning capabilitiesmathematical & learning capabilities• sequential thought processessequential thought processes
right sideright side• visual spatial skillsvisual spatial skills• musical and artistic activitiesmusical and artistic activities• intuitive abilitiesintuitive abilities
The Limbic SystemThe Limbic SystemThe Limbic SystemThe Limbic System
ThalamusThalamus
Relay center for sensory tracts Relay center for sensory tracts from the spinal cord to the from the spinal cord to the cerebrum.cerebrum.
Contains centers for sensation Contains centers for sensation of pain, temperature, and touch.of pain, temperature, and touch.
Involved with emotions and Involved with emotions and alerting or arousal mechanisms.alerting or arousal mechanisms.
HypothalamusHypothalamus
• autonomic control center- blood pressure, autonomic control center- blood pressure, rate and force of heart contraction, center rate and force of heart contraction, center for emotional response and behaviorfor emotional response and behavior
• body temperaturebody temperature• water balance and thirstwater balance and thirst• sleep/wake cyclessleep/wake cycles• appetiteappetite• sexual arousalsexual arousal• control of endocrine functioning:control of endocrine functioning:Acts on the pituitary gland through the Acts on the pituitary gland through the
release of neurosecretions.release of neurosecretions.
Regulates:Regulates:
MidbrainMidbrain
Contains ascending and descending Contains ascending and descending tracts to the cerebrum and thalamus.tracts to the cerebrum and thalamus.
Reflex center for eye muscles.Reflex center for eye muscles. Also involved with processing visual Also involved with processing visual
and auditory information (connects and auditory information (connects head movements with visual and head movements with visual and auditory stimuli).auditory stimuli).
PonsPons
Connects the two halves of the Connects the two halves of the cerebellum.cerebellum.
Regulates breathing.Regulates breathing.
Medulla Medulla OblongataOblongata
• Composed of nerve tracts to and from the brain (these tracts cross over left to right and right to left)
• May be regarded as an extension of the spinal cord
• Almost all of the cranial nerves arise from this region
Medulla OblongataMedulla Oblongata
Contains control centers for Contains control centers for many subconscious activitiesmany subconscious activities• Respiratory rateRespiratory rate• Heart rateHeart rate• Arteriole constrictionArteriole constriction• SwallowingSwallowing• HiccuppingHiccupping• CoughingCoughing• SneezingSneezing
CerebelluCerebellumm
Controls and coordinates muscular activity.
Important in equilibrium, posture and movement.
Traumatic Brain Injuries
• Concussion• Contusion• Subdural or subarachnoid
hemorrhage• Contrecoup injury• Punch Drunk Syndrome
Cerebrovascular Accidents (CVAs)
• Ischemia• Thrombus• Embolism• Arteriosclerosis• Stroke
Stroke
Degenerative brain diseases
• Alzheimer’s• Down’s • Parkinson’s• Huntington’s Chorea• MS• Epilepsy• Schizophrenia
Normal Alzheimer’s
Severely enlarged ventricles
Hippocampus Entorhinal cortex
Extreme shrinkage of cortexCerebral
cortex
Normal Alzheimer’s
Extreme shrinkage of hippocampus
Alzheimer’sNormal
Down’s syndromeEffects transmission of neurons between the locus coeruleus and hippocampus
Problems in using spatial and contextual to form new memories: a function of the hippocampus
Scientists may have cure for Down’shttp://www.sciencedaily.com/releases/2013/07/130717132330.htm
PET ScansF-Dopa deficiency
Parkinson’s Disease
Parkinson’s Disease
Substantia nigra
Huntington’s Disease
Mutated Huntingtin protein toxicity
MS
Epilepsy
Schizophrenia
Too much dopamine and glutamate
The Spinal Cord
The Spinal CordThe Spinal Cord
ventral root
pia mater
dura mater
arachnoid
grey matter
dorsal root
white matter
spinal nerves
Nerve Pathways into the Spinal Cord
Nerve Pathways into the Spinal Cord sensory
pathway
motor pathway
Functional Divisions of the Functional Divisions of the Peripheral Nervous SystemPeripheral Nervous System
Afferent DivisionAfferent Division• Sensory (advances) neuron – Sensory (advances) neuron –
goes toward CNSgoes toward CNSEfferent DivisionEfferent Division
• Motor (exits) neuron- leaves CNSMotor (exits) neuron- leaves CNS• Somatic Nervous SystemSomatic Nervous System• Autonomic Nervous SystemAutonomic Nervous System
Peripheral Nervous System
cranial nerves- 12 pr
spinal nerves- 31 pr
Cranial NervesCranial Nerves
Spinal Reflex Arc
Spinal Reflex Arc
patellar ligament
stretch receptor
motor neuron
sensory neuron
motor neuron
interneuron
The Autonomic Nervous The Autonomic Nervous SystemSystem
Parasympathetic and Sympathetic Nervous System:
• A subdivision of the PNS• Not under conscious control• Work antagonistically• Controlled by medulla oblongata and
hypothalamus• Peripheral nervous system that
supplies stimulation via motor nerves to smooth and cardiac muscle and to glands
Sympathetic DivisionSympathetic Division neurotransmitter is norepinephrine, fight or flight
E = exercise, excitement, emergency, and embarrassment
Parasympathetic DivisionParasympathetic Division neurotransmitter is acetylcholine
D = digestion, deification, diuresis (urinating)
INQUIRY
1. What voltage is the threshold potential?
2. Describe depolarization, repolarization and hyperpolarization.
3. What layer of tissue adheres most tightly to the brain?
4. CFS stands for-------.5. What does it do?6. What does the thalamus do?7. Where is dark matter located in the
spinal cord?8. What disease is characterized by
myelin sheath degeneration?9. A thrombus that moves to a new site is
called ----.