Ch 13 pt 1 – Central Nervous System

Central Nervous System (CNS)

Consists of the brain and spinal cord; responsible for integration and control of the body.

Brain Regions

Four major regions: cerebral hemispheres, diencephalon, brain stem, and cerebellum.

Cephalization

Increased development of the anterior portion of the CNS, especially the brain.

Ventricles

Fluid-filled cavities in the brain continuous with the central canal of the spinal cord.

Lateral Ventricles

Paired C-shaped chambers located deep in each cerebral hemisphere.

Third Ventricle

Located in the diencephalon; connected to lateral ventricles by interventricular foramina.

Fourth Ventricle

Lies in the hindbrain between pons and cerebellum; connected to third ventricle via cerebral aqueduct.

Cerebral Hemispheres

The largest part of the brain, forming the superior part; composed of gray and white matter.

Gyri

Ridges or elevated areas on the brain’s surface.

Sulci

Shallow grooves between gyri.

Fissures

Deep grooves separating major brain regions.

Longitudinal Fissure

Separates the right and left cerebral hemispheres.

Transverse Cerebral Fissure

Separates the cerebral hemispheres from the cerebellum.

Lobes of the Cerebrum

Frontal, parietal, temporal, occipital, and insula.

Central Sulcus

Separates the frontal lobe from the parietal lobe.

Precentral Gyrus

Located anterior to the central sulcus; contains the primary motor cortex.

Postcentral Gyrus

Located posterior to the central sulcus; contains the primary somatosensory cortex.

Lateral Sulcus

Separates temporal lobe from parietal and frontal lobes.

Parieto-Occipital Sulcus

Separates the parietal lobe from the occipital lobe.

Cerebral Cortex

Outer layer of gray matter; site of conscious mind functions such as awareness, memory, and communication.

Gray Matter

Neuron cell bodies, dendrites, and unmyelinated axons; found in cortex and nuclei.

White Matter

Myelinated axons; connects different regions of the CNS.

Functional Areas of the Cerebral Cortex

Motor, sensory, and association areas.

Contralateral Control

Each hemisphere controls the opposite side of the body.

Cerebral Dominance

One hemisphere (usually the left) is dominant for language, math, and logic.

Primary Motor Cortex

Located in precentral gyrus; controls voluntary movement of skeletal muscles.

Premotor Cortex

Plans movements; coordinates learned or patterned motor skills.

Broca’s Area

Controls muscles used in speech production; usually in the left hemisphere.

Frontal Eye Field

Controls voluntary movement of the eyes.

Primary Somatosensory Cortex

Receives sensory input from skin and proprioceptors; located in postcentral gyrus.

Somatosensory Association Cortex

Integrates sensory inputs to produce understanding of an object (size, texture, shape).

Primary Visual Cortex

Receives visual information from the retina.

Visual Association Area

Interprets visual stimuli based on past experiences.

Primary Auditory Cortex

Receives auditory information from inner ear.

Auditory Association Area

Stores memories of sound and interprets them (e.g., speech, music).

Olfactory Cortex

Receives sensory input from smell receptors in nasal cavity.

Gustatory Cortex

Receives taste information; located in the insula.

Visceral Sensory Area

Perception of visceral sensations (upset stomach, full bladder, etc.).

Vestibular (Equilibrium) Cortex

Responsible for awareness of balance and head position.

Multimodal Association Areas

Integrate sensory information with memories and emotions to guide responses.

Anterior Association Area (Prefrontal Cortex)

Involved in intellect, cognition, recall, personality, and judgment.

Posterior Association Area

Recognizes patterns and faces; involved in spatial awareness and understanding language.

Limbic Association Area

Provides emotional impact that helps establish memories.