The Central Nervous System – Lecture Review

A comprehensive set of question-and-answer flashcards covering key anatomical structures, physiological functions, and clinical concepts discussed in the CNS lecture notes.

What two structures make up the Central Nervous System (CNS)?

The brain and the spinal cord.

Ignore

Ignore.

What clinical criterion is accepted as evidence of human demise?

Cessation of brain activity.

In neuroanatomy, what direction does the term “rostral” indicate?

Toward the forehead or newer structural development of the cerebrum.

What does the term “cephalad” describe?

An ascending change in position from the spinal cord toward the brain.

What does the term “caudal” indicate?

A descending change in position from the brain toward the spinal cord.

Name the three major portions of the brain.

Cerebrum, cerebellum, and brainstem.

Approximately what percentage of total brain volume does the cerebrum occupy?

About 83% of brain volume.

Which brain region contains roughly 50% of all CNS neurons?

The cerebellum.

List the three main parts of the brainstem.

Midbrain, pons, and medulla oblongata.

What deep groove separates the two cerebral hemispheres?

The longitudinal fissure.

What are the elevated folds on the cerebral surface called?

Gyri (singular gyrus).

What are the shallow grooves between gyri called?

Sulci (singular sulcus).

What large bundle of nerve fibers connects the two cerebral hemispheres?

The corpus callosum.

In which cranial fossa does the cerebellum sit?

The posterior cranial fossa.

What are the ridge-like folds of the cerebellar cortex called?

Folia.

Which four brain structures comprise the diencephalon?

Thalamus, hypothalamus, epithalamus (including pineal gland and habenula).

Define gray matter in the CNS.

Aggregations of neuron cell bodies, dendrites, and synapses with little myelin.

What term is used for surface layers of gray matter on the cerebrum and cerebellum?

Cortex (cerebral cortex or cerebellar cortex).

What is a nucleus in CNS terminology?

A small, deep mass of gray matter within the brain or brainstem.

What is white matter composed of?

Bundles of myelinated axons (nerve fibers).

Name three examples of white-matter tracts.

Fasciculi, funiculi, decussations (e.g., corpus callosum).

List the three meningeal layers from superficial to deep.

Dura mater, arachnoid mater, pia mater.

What meningeal space contains cerebrospinal fluid?

The subarachnoid space.

What structures return CSF to the venous blood in the superior sagittal sinus?

Arachnoid villi (granulations).

How many ventricles does the brain have?

Four: two lateral ventricles, the third ventricle, and the fourth ventricle.

Which glial cells line the ventricles and secrete cerebrospinal fluid?

Ependymal cells.

Approximately how much CSF does the brain produce and absorb daily?

About 500 mL per day.

Trace the normal CSF flow from lateral ventricles to the spinal cord.

Lateral ventricles → interventricular foramina → third ventricle → cerebral aqueduct → fourth ventricle → central canal (and subarachnoid space via apertures).

Give three primary functions of CSF.

Buoyancy, protection (shock absorption/thermal stability), and chemical stability (waste removal).

What percentage of the body’s blood supply does the brain receive?

About 15% of total blood volume.

What are the two structural components of the blood-brain barrier?

Tight junctions between capillary endothelial cells and astrocytic perivascular feet.

Name the three vital autonomic centers located in the medulla oblongata.

Cardiac center, vasomotor center, and respiratory centers.

Which cranial nerves emerge from the medulla oblongata?

Cranial nerves IX (Glossopharyngeal), X (Vagus), XI (Accessory), XII (Hypoglossal).

Which brainstem structure contains nuclei that regulate sleep, respiration, and posture?

The pons (reticular formation within the pons).

What sensory reflex functions are associated with the superior colliculi?

Visual attention and tracking of moving objects.

What is the main function of the inferior colliculi?

Relay of auditory information from the inner ear to other brain regions, especially the thalamus.

Degeneration of which midbrain nucleus is linked to Parkinson disease?

The substantia nigra.

What branching white-matter pattern is visible inside the cerebellum?

The arbor vitae.

Which peduncles carry most cerebellar output?

The superior cerebellar peduncles (connected to the midbrain).

List three non-motor functions of the cerebellum.

Timekeeping/prediction, spatial perception/texture comparison, and pitch discrimination in hearing.

Name the three major regions of the diencephalon.

Thalamus, hypothalamus, and epithalamus.

Why is the thalamus called the “gateway to the cerebral cortex”?

Because nearly all sensory input to the cerebrum synapses in thalamic nuclei before reaching the cortex.

Give four key homeostatic roles of the hypothalamus.

Hormone secretion (pituitary control), autonomic regulation, thermoregulation, and regulation of hunger/thirst.

Which cerebral lobe is the primary visual center?

The occipital lobe.

Which lobe houses areas for hearing, smell, and memory?

The temporal lobe.

What type of white-matter tract connects the two cerebral hemispheres?

Commissural tracts (e.g., the corpus callosum).

What is the typical thickness of the cerebral cortex?

About 2–3 millimeters.

Name the three major components of the basal nuclei.

Caudate nucleus, putamen, and globus pallidus.

Where do the basal nuclei receive dopaminergic input from?

The substantia nigra of the midbrain.

What color does fresh gray matter appear and why?

Dull whitish-tan because it contains little myelin.

What is the function of arachnoid villi?

They reabsorb CSF into the dural venous sinuses, particularly the superior sagittal sinus.