Chapter 12, 13, 14 Central Nervous System

How does the neural tube develop?

• Begins as neural plate (ectoderm)

• Folds to form neural groove

• Edges fuse → neural tube

• Becomes brain (rostral end) and spinal cord (caudal end)

What is gray matter?

Neuron cell bodies, dendrites, unmyelinated axons

What is white matter?

Myelinated axons (tracts)

Distribution in brain?

• Gray = outer cortex

• White = deeper

Distribution in spinal cord?

• Gray = inner (butterfly shape)

• White = outer

What are the four ventricles?

• Two lateral ventricles

• Third ventricle

• Fourth ventricle

What connects them?

• Interventricular foramina

• Cerebral aqueduct

Function of ventricles?

Contain and circulate CSF

Lobes of cerebrum?

Frontal, Parietal, Temporal, Occipital,

Major fissures?

• Longitudinal fissure

• Transverse fissure

• Lateral sulcus

• Central sulcus

What are sulci and gyri?

• Sulci = grooves

• Gyri = ridges

Cerebral cortex?

Outer gray matter layer; conscious thought

Cerebral medulla?

Internal white matter

Three major basal nuclei areas?

• Caudate nucleus

• Putamen

• Globus pallidus

Function of Basal Nuclei

Regulate voluntary motor control

Primary Motor Area (Location)

Precentral gyrus (frontal lobe)

Primary Motor Area (Function)

Controls voluntary skeletal muscle movement

Primary Motor Area (Interaction with frontal lobe?)

Premotor & motor association areas plan movements

Broca’s area?

Motor speech production (frontal lobe)

Wernicke’s area?

Language comprehension (temporal lobe)

Difference with Broca’s and Wernicke’s

• Broca’s damage → can’t speak properly

• Wernicke’s damage → speech makes no sense

Primary sensory areas?

Receive sensory input (touch, vision, hearing)

Association areas?

Interpret and integrate sensory info

How do they interact?

Sensory → association → response

What is lateralization?

Certain functions localized to one hemisphere

Cerebral dominance?

Usually left hemisphere dominant for language

Three types of tracts? (Cerebral White Matter Tracts)

• Association (same hemisphere)

• Commissural (between hemispheres)

• Projection (connect cerebrum to lower CNS)

What is a sensory homunculus?

Body map in postcentral gyrus (sensory cortex)

What is a motor homunculus?

Body map in precentral gyrus (motor cortex)

Why are some body parts larger?

More cortical tissue = greater control/sensitivity (hands, lips)

Diencephalon

Parts?

• Thalamus

• Hypothalamus

• Epithalamus

Thalamus function?

Sensory relay station

Hypothalamus function?

Homeostasis, hormones, temperature

Epithalamus function?

Includes pineal gland (melatonin)

Brainstem

Parts?

• Midbrain

• Pons

• Medulla oblongata

Function of brainstem

Vital reflexes (breathing, heart rate)

Cerebellum

Regions?

• Hemispheres

• Vermis

• Folia

• Arbor vitae

Function of the Cerebellum

Coordination, balance, motor learning, some cognition

Limbic System

Parts?

• Hippocampus

• Amygdala

• Cingulate gyrus

Function of Limbic System

Emotion, memory

Olfactory impact?

Smell strongly linked to memory & emotion

Reticular Formation

Location?

Brainstem

Function of Reticular Formation

Consciousness & alertness

RAS (Reticular Activating System)?

Maintains wakefulness

Working memory?

Very short, active processing

Short-term memory?

Seconds to minutes

Long-term memory?

• Declarative (facts/events)

• Procedural (skills)

Two types of sleep?

• Non-REM

• REM

Regulation of sleep?

Hypothalamus & brainstem

Importance of sleep

Memory consolidation, repair

Three meninges?

• Dura mater

• Arachnoid mater

• Pia mater

Spaces?

• Epidural

• Subdural

• Subarachnoid (contains CSF)

Where is CSF made?

Choroid plexus

circulation of CSF

Ventricles → subarachnoid space → blood via arachnoid granulations

Function of CSF

Cushioning, nutrient delivery, waste removal

Blood-Brain Barrier

Function?

Protects brain from harmful substances

Spinal Cord

Gross structure?

Cervical & lumbar enlargements, conus medullaris

Spinal Cord

Microscopic structure?

• Gray horns

• White columns

Posterior horn?

Sensory

Anterior horn?

Motor

Lateral horn?

Autonomic

Ascending pathways?

Carry sensory info to brain

Descending pathways?

Carry motor commands from brain