UNIT 3

What structures make up the central nervous system (CNS)?

Brain and spinal cord

What is a dermatome?

An area of the body/skin corresponding to a particular spinal nerve segment

What does afferent mean?

Carries sensory information toward the CNS

What does efferent mean?

Carries motor information away from the CNS

Which spinal root carries sensory information?

Dorsal root

Which spinal root carries motor information?

Ventral root

What is the basic direction of sensory information through the spinal cord?

Sensory neuron → dorsal root → spinal cord

What is the basic direction of motor information through the spinal cord?

Spinal cord → ventral root → motor neuron

What are the meninges?

Protective coverings of the brain and spinal cord

What are the three meninges from outermost to innermost?

Dura mater → arachnoid membrane → pia mater

What does dura mater mean?

Tough mother

What does arachnoid membrane refer to?

The spiderweb-like middle meningeal layer

What does pia mater mean?

Tender mother

What is a hematoma?

A collection of blood outside a blood vessel

What is a subdural hematoma?

A collection of blood between the dura and arachnoid membrane

What is the subarachnoid space?

Space between the arachnoid membrane and pia mater

What fills the subarachnoid space?

Cerebrospinal fluid (CSF)

What is the Circle of Willis?

A collection of interconnected arteries supplying the brain

Why is the Circle of Willis important?

It provides redundancy in circulation that helps protect against loss of blood flow

Which cerebral artery has the highest rate of stroke?

Middle cerebral artery (MCA)

Why is the MCA especially vulnerable to blockage?

It has extensive branching and twisting

Why can an MCA stroke be especially damaging?

The MCA supplies a large amount of cerebral cortex

What are sulci?

Grooves in the cerebral cortex

What are gyri?

Ridges/folds of the cerebral cortex

What is a fissure?

A deep groove separating major regions of the brain

What fissure separates the two cerebral hemispheres?

Longitudinal fissure

What is the central sulcus?

A major groove separating frontal and parietal cortical regions

What are ventricles?

Four connected cavities in the brain filled with CSF

What produces CSF?

Choroid plexus

What type of cells are specialized in the choroid plexus?

Ependymal cells

What is the flow of CSF through the ventricles?

Lateral ventricles → third ventricle → cerebral aqueduct → fourth ventricle

Where can CSF flow after the fourth ventricle?

Into the central canal of the spinal cord or the subarachnoid space

What are major functions of CSF?

Bathes and cushions the CNS

What is gray matter primarily associated with?

Neuron cell bodies and local processing

What is white matter primarily associated with?

Axons connecting different neural regions

What are short white matter connections?

Connections between adjacent areas within a lobe

What are medium white matter connections?

Connections between different lobes within a hemisphere

What tract connects Broca's and Wernicke's areas?

Arcuate fasciculus

What are long white matter connections?

Connections between the cerebral hemispheres

What is the major white matter tract connecting the two hemispheres?

Corpus callosum

What is a commissure?

A bundle of fibers connecting the two hemispheres

What are the major components of the forebrain emphasized in this lesson?

Cerebral cortex, basal ganglia, hippocampus, amygdala, thalamus, hypothalamus

What are the four major lobes of the cerebral cortex?

Frontal, Parietal, Temporal, Occipital

What is the frontal lobe broadly associated with?

Motor and executive functions

What is the parietal lobe broadly associated with?

Somatosensory/tactile processing

What is the temporal lobe broadly associated with?

Auditory and other sensory processing

What is the occipital lobe primarily associated with?

Vision

What is the insula?

A region of cortex hidden deep within the lateral sulcus

What is primary sensory cortex?

Cortex that directly processes incoming sensory information

What are association cortices?

Cortical regions that integrate and interpret information beyond primary sensory or motor processing

Compared with other animals shown

what is especially expanded in humans?

What is the primary somatosensory cortex responsible for?

Processing somatic sensory information such as touch

Where is the primary somatosensory cortex located?

Postcentral gyrus

What is the primary motor cortex responsible for?

Control of voluntary movement

What is the primary visual cortex responsible for?

Initial cortical processing of visual information

What is the primary auditory cortex responsible for?

Initial cortical processing of auditory information

What is the primary gustatory cortex responsible for?

Taste processing

What is the olfactory cortex responsible for?

Smell processing

What are Brodmann areas based on?

Differences in cytoarchitecture such as cell size

Which Brodmann areas are the primary somatosensory cortex?

Areas 3

Which Brodmann area is the primary motor cortex?

Area 4

Which Brodmann area is the primary visual cortex?

Area 17

Which Brodmann area is the primary olfactory/piriform cortex?

Area 27

Which Brodmann areas are the auditory cortex?

Areas 41 and 42

Which Brodmann area is the primary gustatory cortex?

Area 43

Which Brodmann areas make up Broca's area?

Areas 44 and 45

What is the basal ganglia?

A higher-order movement center of the brain

What structures shown are major components of the basal ganglia?

Caudate nucleus

What is the overall role of the limbic system?

Memory and emotion processing

What major structures of the limbic system were emphasized?

Hippocampus, amygdala, cingulate cortex, hypothalamus.

What is the hippocampus strongly associated with?

Memory

Why is the hippocampus called the hippocampus?

The name comes from the Greek word for seahorse

What is the amygdala broadly associated with?

Emotion processing

What are the two major structures of the diencephalon emphasized in this lesson?

Thalamus and hypothalamus

About how many subnuclei does the hypothalamus have?

22

What is a major role of the hypothalamus?

Maintaining homeostasis (hormonal balance)

How does the hypothalamus help control the endocrine system?

It interacts with the pituitary gland to regulate hormones

Which is larger: the thalamus or hypothalamus?

Thalamus

About how many subnuclei does the thalamus have?

20+

Where does the thalamus project?

Directly to areas throughout the cortex

What is the thalamus's major sensory role?

Receives and gates sensory information before it reaches the cortex

Which sensory system is the exception to thalamic sensory gating?

Olfaction

What major divisions were emphasized around the brainstem?

Midbrain and hindbrain

What are the three major components of the midbrain?

Tectum, tegmentum, cerebral peduncles.

What important dopamine-producing structure is located in the midbrain?

Substantia nigra

What canal passes through the midbrain?

Cerebral aqueduct

What structures make up the hindbrain?

Pons

What major functions are associated with the hindbrain?

Balance and coordination, sleep and arousal, breathing, heart rate, and other vital autonomic functions.

What are folia?

Folds of the cerebellum similar to cortical gyri

What is the arbor vitae?

Branching white matter of the cerebellum

What structure connects the two cerebellar hemispheres?

Vermis

What is a major function of the cerebellum?

Coordination of complex movements

What role does the cerebellum play in learning?

Guides motor learning

Rostral

Towards the nose

Caudal

Towards the tail

Anterior

Towards the front

Posterior

Towards the back

Dorsal

Towards the back

Ventral

Towards the belly

Superior

Above