CNS
Created by: its_nikkii
▪ Efferent (motor): CNS to
Nervous System muscles/glands
▪ Interneurons: Connect afferent &
• Functional Unit: Neuron (nerve cell) efferent
• Divisions:
o Central Nervous System (CNS): Properties:
Brain & Spinal Cord (connects brain ▪ Excitability, Conductibility,
& periphery) Permanent (no regeneration)
o Peripheral Nervous System (PNS):
▪ Cranial Nerves (12 pairs): To/from Neuroglia: Support & protect neurons
brain Types:
▪ Spinal Nerves (31 pairs): To/from
spinal cord ▪ Astrocytes: Blood-brain barrier
o Autonomic Nervous System (ANS): ▪ Oligodendria: Myelin in CNS
Involuntary control (e.g., breathing, ▪ Microglia: Phagocytosis
heartbeat). Part of PNS. ▪ Ependymal: Secrete
▪ Sympathetic: "Fight or flight" chemoattractants
(accelerates functions, except GIT) Brain:
▪ Parasympathetic: "Rest and digest"
(normal functioning, increases GIT) o Composition: 80% brain mass, 10%
blood, 10% CSF
Cells:
Parts:
Neurons:
1. Cerebrum: Largest, integration,
▪ Components: Cell body (gray sensory, motor. Lobes:
matter), axon, dendrites ▪ Frontal: Personality, behavior, motor
▪ Axon: Transmits impulses away (precentral gyrus), speech (Broca's
from cell body area)
▪ Dendrites: Receive impulses, ▪ Temporal: Hearing, taste, smell,
conduct towards cell body short-term memory, sensory speech
▪ Synapse: Junction between neurons (Wernicke's area)
▪ Neurotransmitter: Chemical (e.g., ▪ Parietal: Sensory integration
acetylcholine, norepinephrine) for (postcentral gyrus)
impulse transmission ▪ Occipital: Vision
▪ Myelin Sheath: Insulates nerve 2. Diencephalon: Thalamus (relay),
fibers, speeds conduction Hypothalamus (BP, thirst, appetite,
temp, pituitary control)
3. Midbrain: Sight & hearing relay
Functional Classification:
, 4. Brain Stem: Midbrain, pons, medulla Neurological Exam:
oblongata. Vital centers (respiratory,
• LOC: Orientation, speech, command
vasomotor, cardiac)
following, response to pain,
5. Cerebellum: Balance, coordination
posturing (decorticate, decerebrate)
Spinal Cord: • Glasgow Coma Scale (GCS): Eye
o Connects brain & periphery opening, verbal response, motor
o Gray matter (cell bodies) & white response (Score: 15-14 Conscious,
matter (nerve tracts) 13-11 Lethargy, 10-8 Stupor, 7
o Ascending (sensory) & Descending Coma, 3 Deep Coma)
(motor) tracts • Pupillary Reaction: Size, shape,
o Reflex Arc: Sensory receptor, equality, light response
afferent pathway, interneuron, • Motor Function: Strength, movement
efferent pathway, effector • Vital Signs: Respiratory patterns
(Cheyne-Stokes, etc.)
Supporting Structures: Skull, Spinal
• Cranial Nerve Assessment
Column, Meninges (dura, arachnoid, pia),
• Cerebellar Function: Balance,
Ventricles (CSF production), CSF
coordination (Romberg's test)
(protection, nutrients), Vascular Supply,
Blood-Brain Barrier (BBB) • Sensory Function: Touch, pain,
temperature, vibration
Peripheral Nervous System: • Reflexes: Deep tendon, superficial,
• Spinal Nerves: 31 pairs pathologic (Babinski)
(dorsal/sensory, ventral/motor roots) Vision & Hearing
• Cranial Nerves: 12 pairs (sensory,
motor, or mixed functions) Vision:
Autonomic Nervous System: • Physiological Processes: Refraction,
Accommodation,
• Involuntary control of smooth Constriction/Dilation, Convergence.
muscle, cardiac muscle, glands
• Sympathetic (adrenergic): "Fight or Refraction Errors:
flight" (norepinephrine). Dilates • Myopia (nearsighted): Biconcave
pupils (mydriasis), increases HR/BP, lens
bronchodilation, decreases GIT. • Hyperopia (farsighted): Biconvex
• Parasympathetic (cholinergic): "Rest lens
and digest" (acetylcholine). • Astigmatism: Cylindrical lens
Constricts pupils (miosis), decreases
• Presbyopia: Bifocal lens
HR/BP, bronchoconstriction,
• Glaucoma: Increased IOP (Normal:
increases GIT.
12-21 mmHg). Preventable, not
curable.
• Open-angle: Gradual vision loss.