Central Nervous System: The Human Brain

Comprehensive vocabulary flashcards covering the anatomy, regions, and functional areas of the human brain as described in the Central Nervous System lecture.

Neurons in the Human Brain

The brain consists of approximately $85$ billion neurons.

Brain Mass

The human brain has a mass of about $1300\,g$, which is almost $3\,lbs$.

Brain Regions

The four main regions of the adult brain are the cerebral hemispheres, diencephalon, brain stem, and cerebellum.

Gyri

The folds on the surface of the cerebral cortex created as it rolls upon itself to fit into the cranial cavity.

Sulci

Shallow grooves found on the surface of the cerebrum.

Fissures

Deep grooves found on the surface of the cerebrum.

Longitudinal Fissure

The deep groove that separates the cerebrum into right and left halves called cerebral hemispheres.

Central Sulcus

The surface marking that separates the frontal lobe from the parietal lobe.

Transverse Cerebral Fissure

The deep groove that separates the cerebrum from the cerebellum.

Insula

An internal lobe of the brain that is buried under portions of the temporal, parietal, and frontal lobes.

Cerebral Cortex

A thin ($2-4\,mm$) superficial layer of gray matter that serves as the site of the conscious mind, including awareness and memory storage.

Pyramidal Cells

Large neurons located in the precentral gyrus that allow for conscious control of precise, skilled, skeletal muscle movements.

Premotor Cortex

An area anterior to the precentral gyrus that helps plan movements and serves as a staging area for skilled motor activities.

Broca’s Area

A motor speech area, usually present in the left hemisphere, that directs the muscles involved in speech production.

Lateralization

The specialization of cortical functions where certain tasks, such as reasoning or art awareness, occur primarily in one hemisphere.

Primary Somatosensory Cortex

Located in the postcentral gyri of the parietal lobe, it receives general sensory information from the skin and proprioceptors.

Somatosensory Association Cortex

An area posterior to the primary somatosensory cortex that integrates sensory input to determine the size, texture, and relationship of parts of objects being felt.

Primary Visual Cortex

Located on the extreme posterior tip of the occipital lobe, it receives visual information from the retinas.

Primary Auditory Cortex

Located on the superior margin of the temporal lobes, it interprets information from the inner ear as pitch, loudness, and location.

Vestibular Cortex

The part of the insula and adjacent parietal cortex responsible for conscious awareness of balance and head position.

Gustatory Cortex

An area in the insula involved in the perception of taste.

Visceral Sensory Area

An area of the insula involved in the conscious perception of sensations such as an upset stomach or full bladder.

Thalamus

The region of the diencephalon that serves as the major relay station for most sensory impulses reaching the cerebral cortex.

Epithalamus

The region of the diencephalon containing the pineal gland, which secretes melatonin to regulate the sleep-wake cycle.

Hypothalamus

A region of the diencephalon that acts as the autonomic control center, regulating blood pressure, body temperature, hunger, and water balance.

Pons

A brain stem region located between the midbrain and medulla that contains the pneumotaxic and apneustic areas for controlling respiration.

Medulla Oblongata

The part of the brain stem that blends into the spinal cord and acts as an autonomic reflex center for heart contraction, blood pressure, and respiratory rhythm.

Cerebellum

The region occupying the inferior and posterior aspects of the cranial cavity that coordinates skeletal muscle movements and maintains posture and balance.