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 Synapse axon Myelin sheath

bipolar eye, ear, & olfactory Unipolar Dorsal root ganglion cells multipolar most abundant type in CNS Dendrite

Na + K+K+ Outside cell -70mV Inside cell

Presynaptic neuron Postsynaptic membrane Ca 2+ 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- Meninges 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 injury 3.Supplies brain with nutrition 4.Transports hormones along ventricular channels

Cerebrum Parietal Lobe Frontal Lobe Occipital Lobe Temporal Lobe

cerebrum corpus callosum thalamus cerebellum medulla oblongata hypothalamus pituitary pons spinal cord Pineal gland mid brain

Cerebrum b Involved with higher brain functions. b Processes sensory information. b Initiates motor functions. b Integrates information.

Motor, Sensory & Association Cortex Primary motor cortex Primary somatosensory cortex smell hearing vision speech taste reading speech Premotor cortex Broca’s Area Primary Auditory cortex Primary visual cortex Wernicke’s Area Frontal association area

Fig Generating words Max Speaking words Hearing words Seeing words Min

Primary Sensory Cortex

Primary Motor Cortex

Right-Left Specialization of the Cerebrum left side language developmentlanguage development mathematical & learning capabilitiesmathematical & learning capabilities sequential thought processessequential thought processes right side visual spatial skillsvisual spatial skills musical and artistic activitiesmusical and artistic activities intuitive abilitiesintuitive abilities

The Limbic System

Thalamus b Relay center for sensory tracts from the spinal cord to the cerebrum. b Contains centers for sensation of pain, temperature, and touch. b Involved with emotions and alerting or arousal mechanisms.

Hypothalamus autonomic control center- blood pressure, rate and force of heart contraction, center for emotional response and behaviorautonomic control center- blood pressure, rate and force of heart contraction, center for 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 release of neurosecretions. Regulates:

Midbrain b Contains ascending and descending tracts to the cerebrum and thalamus. b Reflex center for eye muscles. b Also involved with processing visual and auditory information (connects head movements with visual and auditory stimuli).

Pons b Connects the two halves of the cerebellum. b Regulates breathing.

Medulla Oblongata 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 Oblongata Contains control centers for many subconscious activities Respiratory rate Respiratory rate Heart rate Heart rate Arteriole constriction Arteriole constriction Swallowing Swallowing Hiccupping Hiccupping Coughing Coughing Sneezing Sneezing

Cerebellum b b Controls and coordinates muscular activity. b b 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

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 cortex Cerebral cortex Normal Alzheimer’s Extreme shrinkage of hippocampus

Alzheimer’s Normal

Down’s syndrome

Effects 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’s

Parkinson’s Disease

PET Scans F-Dopa deficiency Parkinson’s Disease

Substantia nigra

Huntington’s Disease Mutated Huntingtin protein toxicity

MS

Epilepsy

Schizophrenia Too much dopamine and glutamate

The Spinal Cord

ventral root pia mater dura mater arachnoid grey matter dorsal root white matter spinal nerves

Nerve Pathways into the Spinal Cord sensory pathway motor pathway

Functional Divisions of the Peripheral Nervous System Afferent Division Sensory (advances) neuron – goes toward CNSSensory (advances) neuron – goes toward CNS Efferent 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 Nerves

Spinal Reflex Arc patellar ligament stretch receptor motor neuron sensory neuron motor neuron interneuron

The Autonomic Nervous System 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 Division Sympathetic Division neurotransmitter is norepinephrine, fight or flight E = exercise, excitement, emergency, and embarrassment Parasympathetic Division Parasympathetic 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 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 ----.