Principles of Anatomy & Physiology – Chapter 14: The Brain and Cranial Nerves

Vocabulary flashcards covering key structures, functions, and clinical concepts from Chapter 14 of Tortora & Derrickson’s Principles of Anatomy and Physiology, including brain organization, protective features, functional regions, neural development, and cranial nerves.

Neural Tube

Embryonic structure that forms from ectoderm and gives rise to the brain and spinal cord.

Cranial Bones

Part of the skull that provides rigid protection for the brain.

Cranial Meninges

Three connective-tissue membranes (dura mater, arachnoid mater, pia mater) that surround and protect the brain.

Dura Mater

Outer, toughest meningeal layer; in the cranium it has periosteal and meningeal layers.

Falx Cerebri

Dural extension that separates the two cerebral hemispheres.

Tentorium Cerebelli

Dural extension that separates cerebrum from cerebellum.

Blood–Brain Barrier (BBB)

Selective barrier formed by tight junctions in brain capillaries that limits passage of substances from blood to brain tissue.

Cerebrospinal Fluid (CSF)

Clear fluid that cushions the CNS, transports nutrients, and removes wastes.

Choroid Plexus

Network of capillaries in brain ventricles that produces CSF.

Ventricles

CSF-filled cavities within the brain: two lateral, third, and fourth.

Medulla Oblongata

Inferior brainstem region controlling heart rate, breathing, and reflexes like coughing and vomiting.

Pyramids (Medulla)

Anterior bulges of the medulla containing corticospinal motor tracts.

Pons

Brainstem region superior to medulla that relays signals between cerebrum and cerebellum; houses respiratory centers.

Midbrain

Brainstem segment between pons and diencephalon; contains cerebral peduncles and corpora quadrigemina.

Corpora Quadrigemina

Collective term for superior and inferior colliculi, mediating visual and auditory reflexes.

Substantia Nigra

Dark midbrain nucleus whose dopamine neurons help control movement; degeneration linked to Parkinson’s disease.

Red Nucleus

Midbrain structure involved in motor coordination.

Reticular Formation

Network of gray and white matter in brainstem that maintains consciousness and regulates muscle tone.

Cerebellum

Posteroinferior brain region coordinating skeletal-muscle activity and maintaining posture and balance.

Vermis

Central constricted area connecting the two cerebellar hemispheres.

Diencephalon

Brain region consisting of thalamus, hypothalamus, and epithalamus.

Thalamus

Paired mass of gray matter that relays all sensory input (except smell) to the cerebral cortex.

Hypothalamus

Major autonomic and endocrine regulator controlling homeostasis, hunger, thirst, and body temperature.

Epithalamus

Diencephalic roof containing pineal gland and habenular nuclei.

Pineal Gland

Epithalamic endocrine gland that secretes melatonin to regulate circadian rhythms.

Circumventricular Organs (CVOs)

Diencephalic structures lacking BBB that monitor blood chemistry and coordinate endocrine & neural functions.

Cerebrum

Largest brain part; site of higher mental functions; organized into lobes and cortex.

Cerebral Cortex

Outer gray matter layer of cerebrum with gyri, sulci, and fissures.

Corpus Callosum

Major commissural tract connecting right and left cerebral hemispheres.

Gyrus (plural Gyri)

Elevated ridge of cerebral cortex.

Sulcus (plural Sulci)

Shallow groove between gyri on the cortex.

Longitudinal Fissure

Deep groove separating the two cerebral hemispheres.

Frontal Lobe

Cerebral lobe involved in voluntary motor functions, reasoning, and personality.

Parietal Lobe

Lobe that processes somatic sensory information.

Temporal Lobe

Lobe housing auditory, olfactory, and memory functions.

Occipital Lobe

Posterior lobe devoted to vision.

Insula

Deep cerebral lobe involved in gustatory and visceral functions.

Basal Nuclei (Corpus Striatum)

Subcortical gray matter masses that initiate and modulate movements and muscle tone.

Limbic System

Emotional brain involved in memory, motivation, and olfaction.

Primary Somatosensory Cortex

Post-central gyrus region that perceives touch, pressure, pain, and temperature.

Primary Motor Cortex

Pre-central gyrus area that executes voluntary movements.

Association Areas

Cortical regions integrating sensory and motor information, supporting learning, memory, and personality.

Hemispheric Lateralization

Functional specialization between left and right cerebral hemispheres.

Electroencephalogram (EEG)

Recording of brain’s electrical activity via scalp electrodes.

Alpha Waves

EEG rhythm seen in awake, relaxed adults with eyes closed.

Beta Waves

EEG rhythm during active thinking and sensory input.

Theta Waves

EEG rhythm during emotional stress in adults and normal in children.

Delta Waves

Slow EEG rhythm in deep sleep of adults and wakefulness of infants.

Cranial Nerve I – Olfactory

Special sensory nerve for smell.

Cranial Nerve II – Optic

Special sensory nerve for vision.

Cranial Nerve III – Oculomotor

Motor nerve controlling most eye movements, eyelid elevation, pupil constriction, and lens accommodation.

Cranial Nerve IV – Trochlear

Motor nerve that moves the eyeball via superior oblique muscle.

Cranial Nerve V – Trigeminal

Mixed nerve providing facial sensation and chewing movements.

Cranial Nerve VI – Abducens

Motor nerve that abducts the eyeball via lateral rectus muscle.

Cranial Nerve VII – Facial

Mixed nerve controlling facial expression, taste (anterior 2/3 tongue), and salivation/tear secretion.

Cranial Nerve VIII – Vestibulocochlear

Special sensory nerve for hearing and equilibrium.

Cranial Nerve IX – Glossopharyngeal

Mixed nerve for taste (posterior 1/3 tongue), swallowing, and salivation; monitors blood gases and pressure.

Cranial Nerve X – Vagus

Mixed nerve supplying thoracic & abdominal organs; regulates heart rate, GI motility, and vocalization.

Cranial Nerve XI – Accessory

Motor nerve controlling sternocleidomastoid and trapezius muscles.

Cranial Nerve XII – Hypoglossal

Motor nerve for tongue movements in speech and swallowing.

Mnemonic for Cranial Nerves

"Oh Oh Oh To Touch And Feel Very Green Vegetables Ah!" – Olfactory to Hypoglossal.

Stroke (Cerebrovascular Accident)

Loss of brain function due to interrupted blood flow; ischemic (85%) or hemorrhagic (15%).

Transient Ischemic Attack (TIA)

Temporary neurological dysfunction from brief cerebral ischemia, usually resolving within minutes.

Alzheimer’s Disease

Progressive dementia marked by neuronal loss, beta-amyloid plaques, and neurofibrillary tangles.

Brain Tumor

Abnormal proliferation of brain tissue; symptoms vary by size, site, and growth rate.

Attention-Deficit Hyperactivity Disorder (ADHD)

Neurodevelopmental disorder featuring inattention, hyperactivity, and impulsiveness.

Neural Plate

Thickened ectodermal region that folds to form the neural tube during week 3 of development.

Prosencephalon

Embryonic forebrain that later forms telencephalon and diencephalon.

Mesencephalon

Embryonic midbrain; remains midbrain in adult.

Rhombencephalon

Embryonic hindbrain that divides into metencephalon and myelencephalon.

Aging and Nervous System

Characterized by neuron loss, slower impulse conduction, reduced reflexes, and sensory decline.