Nervous System - Anatomy and Physiology LAB - Lecture Slides, Slides of Physiology

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The Central Nervous System

Central Nervous System (CNS) • CNS – composed of the brain and spinal

cord

• Cephalization
  • Elaboration of the anterior portion of the CNS– Increase in number of neurons in the head– Highest level is reached in the human brain

Primary Brain Vesicles

• The anterior end of the neural tube expands

and constricts to form the three primary brainvesicles–

Prosencephalon

• the forebrain

Mesencephalon

• the midbrain

Rhombencephalon

• hindbrain

Neural Tube and Primary Brain Vesicles

Figure 12.2a, b

Secondary Brain Vesicles

Figure 12.2c

Adult Brain Structures

• Fates of the secondary brain vesicles:
  • Telencephalon – cerebrum: cortex, white

matter, and basal nuclei

• Diencephalon – thalamus, hypothalamus, and

epithalamus

• Mesencephalon – brain stem: midbrain– Metencephalon – brain stem: pons– Myelencephalon – brain stem: medulla

oblongata

Basic Pattern of the Central

Nervous System

-^

Spinal Cord^ – Central cavity surrounded by a gray matter core– External to which is white matter composed of

myelinated fiber tracts

-^

Brain^ – Similar to spinal cord but with additional areas of

gray matter

• Cerebellum has gray matter in nuclei– Cerebrum has nuclei and additional gray matter

in the cortex

Basic Pattern of the Central Nervous System

Figure 12.

Ventricles of the Brain

Figure 12.

Cerebral Hemispheres

• Form the superior part of the brain and make

up 83% of its mass

• Contain ridges (gyri) and shallow grooves

(sulci)

• Contain deep grooves called fissures• Are separated by the longitudinal fissure• Have three basic regions: cortex, white

matter, and basal nuclei

• Parieto-occipital sulcus – separates the

parietal and occipital lobes

• Lateral sulcus – separates the parietal and

temporal lobes

• The precentral and postcentral gyri border

Major Lobes, Gyri, and Sulci of the Cerebralthe central sulcus

Hemisphere

Cerebral Cortex

• The cortex – superficial gray matter;

accounts for 40% of the mass of the brain

• It enables sensation, communication,

memory, understanding, and voluntarymovements

• Each hemisphere acts contralaterally

(controls the opposite side of the body)

• Hemispheres are not equal in function• No functional area acts alone; conscious

behavior involves the entire cortex

Functional Areas of the Cerebral

Cortex

Figure 12.8a

Functional Areas of the Cerebral

Cortex

Figure 12.8b