central nervous system (cns) brainbrain spinal cordspinal cord peripheral nervous system (pns)...

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 syndrome

Down’s syndrome

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

Parkinson’s Disease

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 ----.