Central Nervous System Practice Flashcards

Vocabulary flashcards covering the basic organization, structures, cranial nerves, functions, and cellular components of the Central Nervous System.

Central Nervous System (CNS)

Consists of the brain and spinal cord; it controls most functions of the body and mind.

Enteric Nervous System (ENS)

Located in the digestive tract and responsible for autonomous functions; can operate independently of the brain and spinal cord.

Cranium

The skeleton of the head that protects the brain and supports facial structures; includes eight bones of the neurocranium such as the Occipital, Temporal, Parietal, Sphenoid, Ethmoid, and Frontal bones.

Olfactory Nerve I

Cranial nerve responsible for the sense of smell; damage causes an impaired sense of smell.

Optic Nerve II

Cranial nerve that provides vision; damage causes blindness in the visual field.

Oculomotor Nerve III

Controls eye movement (Superior, inferior, medial rectus, and inferior oblique muscles), pupil constriction, focusing, and eye-opening.

Trochlear Nerve IV

Cranial nerve specifically for eye movement involving the superior oblique muscle.

Trigeminal Nerve V

Provides sensations from the face (nasal cavity, forehead, eyelids, lips, teeth, tongue) and motor function for chewing.

Abducens Nerve VI

Cranial nerve that provides lateral eye movement through the lateral rectus muscle.

Facial Nerve VII

Controls facial expressions, salivary and lacrimal glands, and taste on the anterior $2/3$’s of the tongue.

Vestibulocochlear Nerve VIII

Special sensory nerve providing hearing (cochlear branch) and balance (vestibular branch).

Glossopharyngeal Nerve IX

Involved in swallowing, salivation, gagging, and taste on the posterior $1/3$ of the tongue.

Vagus Nerve X

Sensory and motor nerve for thoracic and abdominal viscera, airway relaxation, and heart rate; damage causes hoarseness or loss of voice.

Accessory Nerve XI

Controls swallowing and movement of the head, neck, and shoulders via the trapezius and sternocleidomastoid muscles.

Hypoglossal Nerve XII

Responsible for tongue movements used in speech, food manipulation, and swallowing.

Trigeminal neuralgia

A disorder characterized by recurring episodes of intense stabbing pain in the trigeminal nerve area near the mouth or nose.

Bell’s palsy

A disorder of the facial nerve causing paralysis of facial muscles on one side, typically with full recovery within $3\text{--}5$ weeks.

Cerebrum

The largest part of the brain (75\text{%} by volume), divided by the longitudinal fissure into two hemispheres linked by the corpus callosum.

Cerebral Cortex (Gray Matter)

The outer layer of the cerebrum, approximately $2\text{--}4mm$ thick, composed mostly of neuron cell bodies.

Frontal Lobe

Brain region responsible for volition, voluntary movement, speech initiation, planning, emotions, learning, and social behavior.

Parietal Lobe

Lobe involved in processing somatosensory inputs from the body and stereognosis (recognizing objects by touch).

Temporal Lobe

Contains the primary auditory area for hearing and Wernicke’s area for comprehension of spoken languages.

Occipital Lobe

The centre of vision, concerned with perception, interpretation, and recognition of visual impulses.

Cerebellum

Coordinates postural reflexes to maintain balance and refines learned routines for skilled movements.

Hippocampus

Limbic system structure in the medial temporal lobe essential for consolidating short-term memory into long-term memory.

Basal Ganglia

A collection of nuclei (caudate, putamen, globus pallidus, etc.) that regulate movement and cognitive functions.

Limbic System

Neuronal circuitry (including the amygdala and hypothalamus) associated with emotions, survival instincts, and motivational drives.

Midbrain (Mesencephalon)

Part of the brainstem containing superior and inferior colliculi for visual and auditory reflexes.

Pons

Acts as a bridge in the brainstem; contains apneustic and pneumotaxic respiratory control centers.

Medulla Oblongata

Contains vital centers for cardiovascular control and respiratory rhythmicity; connects the brain to the spinal cord.

Thalamus

A paired structure in the diencephalon that serves as a processing center for sensory information.

Hypothalamus

Diencephalon structure regulating emotion, sleep, heart rate, temperature, hunger, and sex drive.

Conus medullaris

The tapered inferior end that marks the official clinical end of the spinal cord proper.

Cauda equina

A collection of nerve roots projecting inferiorly from the conus medullaris, resembling a horse's tail.

Spinal Meninges

Protective membranes (Dura mater, Arachnoid mater, and Pia mater) that encircle the spinal cord.

Reflex

A rapid, automatic, and involuntary reaction of effectors to a stimulus.

Circle of Willis

A vascular structure on the inferior surface of the brain where branches of the internal carotid and vertebral arteries link.

Neuroglia (Glial cells)

Support cells that make up half the CNS volume; they outnumber neurons by $50\times$ and protect the nervous system.

Astrocytes

CNS glia that create a supportive framework, form the 'blood-brain barrier,' and regulate interstitial fluid.

Oligodendrocytes

Glial cells that form the myelin sheath around axons in the Central Nervous System.

Microglia

Cells referred to as 'brain macrophages' that phagocytize cellular waste and pathogens.

Schwann cells

PNS neuroglia that envelope nerve fibers to produce myelin sheaths and assist in fiber regeneration.

Myelin

A whitish, fatty segmented sheath around long axons that electrically insulates fibers and increases impulse speed.

Dendrites

Neuron parts specialized to receive signals from neighboring neurons and carry them back to the cell body.

Action Potential

An electrical current sent down the axon; it follows an 'all or none process' to facilitate neuronal communication.

Synapse

A junction or structure that permits a neuron to pass electrical or chemical signals to another cell or effector.

Neurotransmitters

Chemical substances stored in axon terminals (e.g., Dopamine, Serotonin) that transmit signals across the synaptic cleft.

Afferent Nerves

Sensory nerves that transmit signals from receptors in the sense organs or skin to the CNS.

Efferent Nerves

Motor nerves that transmit signals from the CNS to the muscles and glands.

Somatic Nervous System

Part of the PNS that regulates body activities under conscious (voluntary) control, such as skeletal muscle movement.

Sympathetic Division

The 'fight, flight, or fright' division of the ANS that mobilizes body systems during activity.

Parasympathetic Division

The 'rest and digest' division of the ANS that conserves energy and promotes routine housekeeping functions.