Anatomy & Physiology: The Brain and Cranial Nerves

Flashcards covering the fundamentals of brain anatomy, physiological regions, developmental vesicles, protection mechanisms, and the functions of the twelve cranial nerves based on Chapter 14 notes.

Adult human brain weight

The average weight is approximately $1.4\,kg$ ($3\,lb$).

Average brain volume

Typically $1200\,mL$, ranging from $750\,mL$ to $2100\,mL$ in functionally normal individuals.

Brainstem

The region that processes and relays information between the spinal cord and the cerebrum or cerebellum; it includes the midbrain, pons, and medulla oblongata.

Gyri

Rounded elevations on the cerebral cortex that increase surface area.

Sulci

Shallow depressions located between the gyri of the brain.

Fissures

Deep grooves found on the surface of the brain.

Cerebellum

The second-largest part of the brain responsible for coordinating ongoing body movements.

Diencephalon

Integration center consisting of the thalamus for sensory relay and the hypothalamus for autonomic functions and hormone production.

Primary brain vesicles

The three initial subdivisions of the cephalic neural tube: the prosencephalon (forebrain), mesencephalon (midbrain), and rhombencephalon (hindbrain).

Telencephalon

The secondary brain vesicle derived from the prosencephalon that eventually becomes the cerebrum.

Myelencephalon

The secondary brain vesicle that develops into the medulla oblongata.

Septum pellucidum

The medial partition that separates the two lateral ventricles.

Interventricular foramen

An opening that allows communication between each lateral ventricle and the third ventricle.

Cerebral aqueduct

A narrow canal in the midbrain that connects the third and fourth ventricles.

Cranial meninges

Three protective layers surrounding the brain: the dura mater, arachnoid mater, and pia mater.

Dural folds

Inward extensions of the inner fibrous layer of the dura mater that stabilize and support the brain, including the falx cerebri and tentorium cerebelli.

Epidural hemorrhage

A condition where blood is forced between the dura mater and the skull, creating pressure that distorts brain tissue.

Blood-brain barrier (BBB)

A system formed by capillary endothelial cells with tight junctions and astrocytes that isolates the CNS from general circulation and allows selective transport.

Cardiovascular centers

Nuclei in the medulla oblongata that adjust heart rate, cardiac contractility, and peripheral blood flow.

Respiratory rhythmicity centers

Medullary centers that set the basic pace for respiratory movements.

Pons

The brain region containing the apneustic and pneumotaxic centers involved in respiration control.

Superior colliculi

Sensory nuclei in the midbrain tectum that process visual sensations and reflexes.

Inferior colliculi

Sensory nuclei in the midbrain tectum that process auditory sensations and reflexes.

Substantia nigra

A midbrain nucleus that produces dopamine to inhibit basal nuclei activity; its degradation is linked to Parkinson’s disease.

Arbor vitae

The highly branched internal white matter of the cerebellum, also known as the "tree of life."

Ataxia

A disturbance in muscular coordination that can be caused by trauma, stroke, or temporary alcohol intoxication.

Pineal gland

Part of the epithalamus that secretes melatonin to regulate reproductive functions and day-night cycles.

Interthalamic adhesion

A projection of gray matter extending into the third ventricle that connects the left and right sides of the thalamus.

Infundibulum

A narrow stalk connecting the hypothalamus to the pituitary gland.

Hippocampus

A limbic system nucleus essential for learning and the storage of long-term memories.

Amygdaloid body

A limbic system component that acts as an interface between the limbic system, cerebrum, and sensory systems; it also regulates autonomic responses to emotions.

Basal nuclei

Deep masses of gray matter, including the caudate and lentiform nuclei, that provide subconscious adjustment of voluntary motor commands.

Wernicke’s area

An integrative center, typically in the left hemisphere, responsible for language comprehension.

Broca’s area

An integrative center, typically in the left hemisphere, responsible for speech production via the regulation of vocalization and breathing patterns.

Alpha waves

Brain waves observed in healthy, awake adults who are at rest with their eyes closed.

Beta waves

Higher-frequency brain waves seen in adults who are concentrating or experiencing mental stress.

Delta waves

Large-amplitude, low-frequency brain waves typically seen during sleep in infants or in awake adults with brain damage.

Cranial Nerve I (Olfactory)

Special sensory nerve responsible for the sense of smell.

Cranial Nerve II (Optic)

Special sensory nerve responsible for vision.

Cranial Nerve V (Trigeminal)

The largest cranial nerve; a mixed nerve responsible for sensory information from the face and motor control for mastication.

Cranial Nerve X (Vagus)

A widely distributed mixed nerve that provides visceral motor control to the digestive, respiratory, and cardiovascular systems.

Corneal reflex

A somatic reflex where contact with the corneal surface triggers the motor nucleus of the facial nerve to cause blinking.