CENTRAL NERVOUS SYSTEM BRAIN CU BOULDER ANATOMY

2026 exam 3

Functional MRI (fMRI) of brain used to study brain function

measures change in blood flow to regions of brain → use of oxygen by cells

Wernicke’s area:

region of brain that recognizes spoken word

brain weighs

3-3.5 lbs with 100 billion interneurons

Brain protected by:

•Skull

•Coverings called meninges

•Dura mater

•Arachnoid mater

•Pia mater

Dura mater

outer layer

2 layers of dense irregular CT

Blood sinus (dural sinus) contained between layers

Layers fused where there is no sinus

Arachnoid mater

middle layer

•Reticular CT

•Spider web like extensions connect  it w/ pia mater

Pia mater

inner layer

•Loose areolar CT

•Clings to brain surface

•Very vascular

Subdural space

space between dura mater & arachnoid mater that contains thin film of fluid

Subarachnoid space

space between arachnoid mater & pia mater that contains Cerebrospinal Fluid

CSF

is a blood filtrate produced w/in the brain that circulates w/in and around the brain

Functions of Cerebrospinal Fluid:

Nourishes brain tissue and removes waste products

Cushion brain → brain floats within a thin layer of CSF

•Approx ½ cup present at any given time

CHOROID PLEXUS

capillary network within ventricles that produces CSF

ARACHNOID VILLI

structures where CSF is reabsorbed back into blood after circulation

Ventricles

connected, fluid containing spaces within the brain

•Lined by ependymal cells

•Filled w/ CSF

top to bottom ventricles of the brain

Lateral ventricles (2)

Third ventricle (1)

Cerebral aqueduct (1)

Fourth ventricle (1)

(Central canal)

Hydrocephaly

CSF is overproduced and/or not removed properly causing an increase in head size (swelling) in infants

Meningitis

Inflammation of meninges, typically caused by infection
The infection can spread to the nervous tissue of brain causing swelling and cell death

viral meningitis

most common but often resolves within a few weeks

bacterial meningitis

most dangerous, but can be treated with antibiotics

Capillaries of brain

specialized continuous capillaries

•Tightly packed endothelial cells lacking in intercellular clefts

•Many more tight junctions

•Restricts what can enter brain tissue

The white matter of the brain gets its look from the fatty, insulatory cells it contains.  Which cells are these?   A.  Neurons   B.  Schwann cells   C.  Oligodendrocytes   D.  Satellite cells   E.  Ependymal cells

C

White matter

Composed of myelinated axons

Form fiber tracts

Gray matter

Composed of:

•Dendrites

•Cell bodies

•Glial cells (supporting cells)

•Unmyelinated axons

the spine possesses no

outer grey matter

the brain develops into 5 distinct regions

1. TELENCEPHALOn

• cerebral hemisphere - cortex

  *white matter

  *basal nuclei

2. DIENCEPHALON

• Thalamus

  Hypothalamus

  Epithalamus

3. MESENCEPHALON

• midbrain

4. METENCEPHALON

• pons

• cerebellum

5. MYELENCEPHALON

• medulla oblongata

BRAINSTEM

formed of midbrain, pons, and medulla oblongata

CEREBRUM

•83% of total brain mass

•Two hemispheres (right & left)

•Complex neural networks

Gray matter

•Cerebral cortex

•Basal nuclei (ganglia)

Cortex

higher order brain functions

Cognition

  -thinking

  -reasoning

  -remembering/memory

*Personality

*Interpretation of sensory impulses

*Initiation of voluntary movements

*Communication

Fiber tracts

bands of myelinated axons (white matter)

3 types of fiber tracts

1. Projection fibers → allows comn between cortex and rest of nervous system

• decussation → fibers cross over left ti right or vice versa

2. Commissural fibers

• allows communication between cerebral hemispheres

3. Association fibers → allows for communication between different parts within the same hemisphere

Corpus callosum

is largest commissural fiber tract

Lobes of cerebrum made up of cerebral cortex

1.Frontal lobe

2.Parietal lobe

3.Occipital lobe

4.Temporal lobe

5.Insula

Cortex contains 3 primary types of processing areas:

1.Sensory areas → Interpret sensory information coming into brain

2.Motor areas → dictate motor responses

3.Association areas → receive and integrate info from multiple areas; store memories; assist with coordinated responses

Frontal lobe:

Personality; cognition; impulse control; voluntary motor control

Primary motor cortex

•Concious control of skeletal muscles

•Damage → loss of voluntary muscle control

Premotor cortex

•Association area

•Coordination of repetitive learned motor skills

•Damage → loss of skill, but can still perform

Prefrontal cortex →

most complicated cortical region; association area

Prefrontal cortex processes emotions and

social interactions = PERSONALITY

in the prefrontal cortex working memory for object-recall tasks =

COGNITION

in the prefrontal cortex solving complex, multitask problems equals

intelligence

damage to the prefrontal cortex means…

mental & personality disorders

Phineas Gage (1823-1860)

personality switched before and after accident that gave him essentially a lobotomy in 1848, became rude and crude

No apparent damage to:  intelligence, memory, speech, movement

PARIETAL LOBE

Input and interpretation of sensory information coming from somatic senses (touch, temp., pain, pressure, etc)

Primary somatosensory cortex

Receives input from somatic sensory receptors of body

part of parietal lobe

Somatosensory association area

Interpret sensory information based on prior experiences

Part of parietal lobe

Damage to parietal lobe may lead to

Unable to identify an object by touch (can still ID by sight which is processed by different region of brain)

TEMPORAL LOBE

Receives and interprets sound sensory information coming from the inner ear; and smell coming from nasal cavity

Primary auditory cortex

Receives sensory information from inner ear

Part of temporal lobe

Auditory association area

Recognition of past sounds

•Wernicke’s area → recognition of spoken words

Part of temporal lobe

Primary olfactory cortex

Input from smell receptors

Association area allows for recognition of smells

Part of Temporal Lobe

Occipital lobe

•Receives and interprets stimuli coming from retina of eye

Primary visual cortex

Receives information coming from receptors in retina of eye

Part of Occipital Lobe

Visual association area

Memories of images; analysis of color, form, movement

Part of Occipital Lobe

Insula

Gustatory cortex

Taste:  receives and interprets sensory information coming from taste buds of tongue

Limbic System:

Structures found within cerebrum  & diencephalon;Emotional brain

Key structures found deep to cortex of temporal lobe (also part of limbdic system)

•Amygdalaà memory of fears; regulates anger; proper response to social cues

Linked to anxiety, autism, and depression

The diencephalon consists of which structures of the brain?  

A. Thalamus  

B.  Hypothalamus  

C.  Epithalamus  

D.  Thalamus & epithalamus  

E.  Thalamus, hypothalamus, & epithalamus

E.

Nuclei w/in hypothalamus regulate:

Hunger/thirst → monitors concentration of salts & nutrients in blood

Body temp → initiates sweating/shivering in response to blood temp changes

Controls smooth muscle, cardiac muscle, glands

•Blood pressure

•Digestion

•respiration

Limbic system control center

Hypothalamus regulates the release of hormones from pituitary gland

  ENDOCRINE

MIDBRAIN

contains nuclei within corpora quadrigemina

The corpora quadrigemina and cerebral aqueduct makeup the midbrain

Corpora quadrigemina of midbrain is made up of

Superior colliculi

Visual reflexes à ability to follow movements

Inferior colliculi

Auditory reflexes à ability to react to sound

Superior colliculi

Visual reflexes à ability to follow movements

Inferior colliculi

Auditory reflexes à ability to react to sound

Pons

•  Respiration regulates speed of inhalation/exhalation

•“bridge” between cerebrum & cerebellum

Arbor vitae

White matter

Carries info

Cerebellar Cortex

Gray matter

Processes info

The cerebellum smooths & coordinates muscle movements using:

1.Current movements

Proprioceptors in skeletal muscles send information on where body parts are

2.Planned movements

Information from cerebral cortex on planned movements

3.Equilibrium

Information from inner ear on if you are standing up, laying down, etc

Basic life support functions medulla oblongata

•Controls heart rate & force of contractions

•Regulates blood pressure

•Breathing rate

Relay station for sensory info entering brain

STROKE: 

Interruption of blood flow to a region of the brain resulting in neuronal cell death (blood clot or aneurysm)

Anton Raderscheidt 1892-1970

•German artist

•Suffered stroke to right parietal & occipital cortex

•Result:

–Left sided neglect  VISUAL

–Loss of spatial skills (relations of objects in space)

•Art therapy documents brain healing

PLASTICITYà ability to reorganize neural pathways