Nervous System and Brain Anatomy Flashcards

Flashcards covering basic nervous system anatomy, cranial nerve functions, brain lobes, meninges, diencephalon, limbic system, and brainstem controls from Lecture Chapters 12 and 13.

Endoneurium

An areolar connective tissue layer wrapping around a myelinated axon that helps provide electrical insulation.

Perineurium

A dense irregular connective tissue layer wrapping around a fascicle, which contains blood vessels.

Fascicle

A group or bundle of myelinated axons wrapped in endoneurium.

Epineurium

A dense irregular connective tissue layer wrapping around several fascicles to form a nerve.

Sensory Nerves

Nerves that contain sensory neurons transmitting functional sensory signals to the Central Nervous System (CNS).

Motor Nerves

Nerves that contain motor neurons transmitting motor output signals away from the Central Nervous System (CNS).

Mixed Nerves

Nerves containing both sensory and motor neurons; most named nerves belong to this category.

Cranial Nerve I (Olfactory)

A cranial nerve responsible purely for sensory olfactory (smell) function.

Cranial Nerve II (Optic)

A cranial nerve responsible purely for sensory visual function.

Cranial Nerve III (Oculomotor)

A cranial nerve providing somatic motor control to four extrinsic eye muscles and levator palpebrae superioris, as well as parasympathetic control to constrict pupils and round the lens.

Cranial Nerve IV (Trochlear)

A cranial nerve providing somatic motor innervation exclusively to the superior oblique eye muscle.

Cranial Nerve V (Trigeminal)

A cranial nerve providing general sensory input from the face, oral cavity, teeth, and anterior two-thirds of tongue, and motor control to muscles of mastication.

Cranial Nerve VI (Abducens)

A cranial nerve providing somatic motor control exclusively to the lateral rectus eye muscle.

Cranial Nerve VII (Facial)

A cranial nerve providing taste sensory from the anterior two-thirds of the tongue, somatic motor control to muscles of facial expression, and parasympathetic control to lacrimal and salivary glands.

Cranial Nerve VIII (Vestibulocochlear)

A cranial nerve dedicated to sensory hearing via its cochlear branch and equilibrium via its vestibular branch.

Cranial Nerve IX (Glossopharyngeal)

A cranial nerve responsible for taste and general sensory input from the posterior one-third of the tongue, motor to the stylopharyngeus muscle, and parasympathetic secretion from the parotid salivary gland.

Cranial Nerve X (Vagus)

A cranial nerve providing visceral sensory info from thoracic and abdominal organs and parasympathetic motor control that slows heart rate, constricts bronchioles, and increases digestive secretions.

Cranial Nerve XI (Accessory)

A cranial nerve providing somatic motor control to the trapezius and sternocleidomastoid muscles.

Cranial Nerve XII (Hypoglossal)

A cranial nerve supplying somatic motor innervations to intrinsic and extrinsic tongue muscles.

M2 Muscarinic Receptor

Receptor on the heart through which Vagus nerve stimulation causes IPSPs, slowing heart rate from the SA node baseline of $100\,\text{bpm}$ down to $60\text{--}80\,\text{bpm}$.

Gastroparesis

A condition characterized by impaired stomach motility, which can be caused by impairment of the vagus nerve.

Oligodendrocytes

Glial cells responsible for forming myelin sheaths around axons within the Central Nervous System.

CNS Tracts

Bundles of myelinated axons in the white matter of the CNS that lack connective tissue coverings.

Excitability

A neuron characteristic defined as responsiveness to a stimulus by changing membrane potential.

Conductivity

The ability of a neuron to propagate an electrical signal sequentially along voltage-gated channels.

Receptive Segment

The region of a neuron comprising dendrites and cell body where neurotransmitter binding triggers excitatory or inhibitory postsynaptic potentials.

Initial Segment

The axon hillock region where signal summation occurs to determine if threshold is reached.

Conductive Segment

The length of the axon responsible for propagating an action potential.

Transmissive Segment

The synaptic knobs of a neuron responsible for neurotransmitter release.

Pia Mater

The delicate, innermost cranial meningeal layer composed of areolar connective tissue that tightly adheres to every brain contour.

Arachnoid Mater

The middle cranial meningeal layer consisting of a web-like network of collagen and elastic fibers that houses the CSF-containing subarachnoid space.

Dura Mater

The tough, outermost cranial meningeal layer composed of dense irregular connective tissue divided into periosteal and meningeal layers.

Subdural Hematoma

A medical condition caused by bleeding into the potential subdural space between the dura mater and arachnoid mater.

Gyrus

An elevated fold of brain tissue created as the cerebral tissue folds on itself.

Sulcus

A shallow depression located between individual gyri folds.

Fissure

A deep groove on the surface of the brain, such as the longitudinal or transverse fissure.

Corpus Callosum

A large tract of white matter connecting the left and right cerebral hemispheres to allow interhemispheric communication.

Frontal Lobe

Cerebral lobe containing the precentral gyrus; controls voluntary motor functions, concentration, verbal communication, decision making, planning, and personality.

Parietal Lobe

Cerebral lobe containing the postcentral gyrus; responsible for processing incoming somatosensory information.

Temporal Lobe

Cerebral lobe dedicated primarily to processing hearing and smell.

Occipital Lobe

Cerebral lobe dedicated to processing visual information.

Insula

Deep cerebral lobe involved in memory and the interpretation of taste.

Precentral Gyrus

Gyrus located in the frontal lobe housing the primary motor cortex, which controls voluntary skeletal muscle movement.

Postcentral Gyrus

Gyrus located in the parietal lobe housing the primary somatosensory cortex, which receives sensory input from skin and joints.

Thalamus

Diencephalon structure serving as the principal relay center for incoming sensory information.

Hypothalamus

Diencephalon structure governing homeostasis, ANS control, endocrine regulation, body temperature, food and water intake, emotional behavior, and circadian rhythms.

Epithalamus

Diencephalon region containing the pineal gland, which secretes melatonin to regulate circadian rhythms.

Hippocampus

Limbic system structure essential for long-term memory formation and short-term memory processing.

Amygdaloid Body

Limbic system structure involved in processing emotional memory, particularly fear and anxiety.

Fornix

A tract of white matter (myelinated axons) connecting the hippocampus to other regions of the brain.

Reticular Activating System (RAS)

Brain region processing visual, auditory, and touch stimuli to activate consciousness, functioning as the body's alarm clock.

Superior Colliculi

Paired structures on the tectal plate of the midbrain responsible for processing visual reflexes.

Inferior Colliculi

Paired structures on the tectal plate of the midbrain responsible for processing auditory reflexes.

Pontine Respiratory Center

Autonomic center located within the pons that helps control breathing rate.

Medulla Oblongata

Inferior brainstem structure containing the medullary respiratory center, cardiac center, and vasomotor center.