Chapter 10: The Nervous System: The Brain and Cranial Nerves

Cerebrum

right and left cerebral hemispheres divided by the longitudinal fissure

Diencephalon

between the cerebral hemispheres

Brain stem

midbrain, pons, and medulla oblongata

Cerebellum

below both parts of cerebrum

Meninges

• Three layers of connective tissue around the spinal cord and brain
• Protective covering

Dura mater

thickest and toughest, 2 layers thick with occasional sinus

Arachnoid

loosely attached to the dura

Pia mater

holds blood vessels

Cerebrospinal Fluid (CSF)

• Clear liquid
• Circulates in and around the brain and spinal cord
• Shock absorber
• Carries nutrients
• Lotsa glucose

cerebr/o

(brain)

Ventricles

4 spaces within the brain

Choroid Plexus

vascular network within the ventricle that forms CSF

chori/o

(membrane)

Lateral ventricles

largest in the 2 cerebral hemispheres with extensions (Horns) into the cerebrum

Cerebrum, diencephalon, brain stem, cerebellum

What are the main divisions of the brain?

Dura mater, arachnoid, pia mater

What are the names of the three layers of the meninges from the outermost to the innermost?

Choroid plexus

Where is CSF produced?

Cerebral Hemispheres

• Each hemisphere has 4 lobes named after the bones covering them
• Frontal, parietal, temporal, occipital

Cerebral Cortex

outer layer of gray matter, thin; responsible for conscious thought, abstract reasoning

Cerebral Hemispheres- Separated by the

Longitudinal Fissure

Insula

deep 5th lobe

Cerebral Cortex Structure- Gyrus (Gyri)

folds in the cortex

Sulcus (Sulci)

shallow grooves between gyri

Central Sulcus

between frontal and parietal lobes

Lateral Sulcus

separates temporal from parietal and frontal

Cerebral Cortex Structure

Made mostly of gray matter with few areas of white matter

Cerebral Cortex Structure-
Basal Nuclei (AKA Basal Ganglia)

masses of gray matter deep in the hemispheres
– Regulate body movements and facial expressions
– Secrete dopamine

Corpus Callosum

band of white matter at the bottom of the longitudinal fissure
Bridge between the right and left hemispheres

Internal Capsule

mylenated fibers that carry impulses between the cerebrum and the brain stem; vertical fibers

Cerebral Cortex Function

• Nerve impulse interpretation
• Stores information (memory)
• Thought processes, conscious deliberation and voluntary actions

Frontal lobe

primary motor area (speech Broca)

Parietal lobe – primary sensory area

estimation of distances, sizes, and shapes

Temporal lobe

auditory (Wernicke) and olfactory

Occipital lobe

sight

Communication Areas Auditory

Lie in the temporal lobe

Auditory receiving area

detects sounds from the environment