Central Nervous System and Spinal Cord (in-depth)

What structures make up the CNS?

brain and spinal cord

What are the meninges?

protective membranes surrounding the brain

Order of meninges (superficial → deep)

dura mater → arachnoid mater → pia mater

Which meningeal layer is tough and outermost?

dura mater

Which meningeal layer does NOT follow sulcus?

arachnoid mater

Which meningeal layer clings to the brain folds?

pia mater

Epidural space contains what?

fat and veins

Where is the epidural space located?

outside the dura mater

What is the subdural space?

a potential space between dura and arachnoid

Which space contains CSF and blood vessels

subarachnoid space

Which spaces ONYL contains CSF?

subarachnoid space

Brain Hierarchy (largest → smallest)

cerebrum → diencephalon → brainstem → cerebellum

Three main parts of the cerebrum?

cerebral cortex, white matter, basal nuclei

What is the cerebral cortex made of?

gray matter

What is white matter?

internal wiring of the brain

Function of the basal nuclei

motor control and movement regulation

Corpus callosum?

white matter tract connecting the two hemispheres

Precentral gyrus function

primary motor cortex p

Postcentral gyrus function

primary somatosensory cortex

What does contralateral mean?

each hemisphere controls the opposite side of the body

Frontal lobe function

motor control, personality, judgement

Parietal lobe function

sensory processing

Temporal lobe function

hearing and language

Occipital lobe function

vision

Insula function

visceral sensory processing

What is somatotopy?

body mapping on the sensory cortex

Which body parts have the largest cortical representation

hands and face

Thalamus function

sensory relay to the cerebral cortex

Hypothalamus function

homeostasis control center

Hypothalamus controls what?

temperature, hunger, thirst, hormones, autonomic system, sleep

Brainstem components

midbrain, pons, medulla oblongata

Midbrain function

visual and auditory reflexes; dopamine production

Pons function

breathing regulation and relay to cerebellum

Medulla oblongata function

heart rate, breathing, blood pressure, reflexes

Why is the medulla oblongata vital?

it controls life-sustaining functions

Cerebellum function

balance, posture, smooth coordinated movement, timing

Limbic system function

emotion and memory processing H

Hippocampus function

memory function

Amygdala function

fear and aggression

Reticular formation function

wakefulness, attention, muscle tone

What is RAS?

reticular activating system

Damage to RAS causes what?

coma

Dorsal column function

fine touch, vibration, proprioception

Spinothalamic tract function

pain and temperature

Spinocerebellar tract function

subconscious proprioception and coordination feedback

Where does the spinal cord end?

L1/L2 vertebral level

Cauda equina?

bundle of spinal nerves below the cord

Conus medullaris?

tapered end of the spinal cord

Gray matter location

central H-shaped region

White matter location

outer region of the spinal cord

Dorsal horn function

sensory

Ventral horn function

motor

Lateral horn function

autonomic (T1-L2)

Pyramidal tract function?

precise voluntary movement

Indirect motor pathways function

posture, balance, reflex movement

Broca’s area function

motor speech production

Damage to Broca’s area causes

broken, nonfluent speech

Wernicke’s area funciton

language comprehension

Damage to Wernicke’s area causes

fluent but meaningless speech

Short-term memory capacity

7-8 chunks

Long-term memory characteristics

unlimited storage; requires consolidation

Declarative memory

facts and information

Procedural memory

skills and actions

Retrograde amnesia

loss of old memories

Anterograde amnesia

inability to form new memories

Levels of consciousness (least → most severe)

alert → drowsy → stupor → coma

Syncope definition

temporary fainting due to decreased blood flow

REM sleep characteristics

dreaming, brain active, body paralyzed

Suprachiasmatic nucleus function

biological clock control

Orexin function

promotes wakefulness

Alpha waves

relaxed, calm state

Theta waves

light sleep; common in children

Delta waves

deep sleep

Beta waves

awake; brain is working

Narcolepsy

sudden sleep attacks

Cataplexy

sudden loss of muscle tone

Insomnia

chronic inability to sleep

Falx cerebri

separates hemispheres

Falx cerebelli

cerebellum division

Tentorium cerebellum

“tent over cerebellum”

First-order neurons?

from receptor → spinal cord

Second-order neurons?

spinal cord → thalamus/cerebellum

Third-order neurons?

thalamus → cortex

Upper motor neurons?

brain → spinal cord

Lower motor neurons

spina cord → muscle