CH 14 Brain and Cranial Nerves

Flashcards covering the anatomy and physiology of the brain and cranial nerves, including major regions, meninges, CSF circulation, brain waves, and the 12 cranial nerves.

Cerebrum

The largest region of the brain, divided into left and right hemispheres and covered by the cerebral cortex; responsible for conscious thoughts, sensations, intellect, memory, and complex movements.

Cerebellum

The second largest brain region that adjusts ongoing movements by comparing arriving sensations with previously experienced sensations to allow for repetitive movement patterns.

Thalamus

Part of the diencephalon that acts as a relay and processing center for sensory information, often referred to as the 'air-traffic controller'.

Hypothalamus

A region of the diencephalon involved with emotions, autonomic function, and hormone production; it serves as the link between the nervous and endocrine systems.

Midbrain

Part of the brainstem that processes visual and auditory information and controls reflexes triggered by these stimuli.

Pons

A brainstem structure involved with somatic and visceral motor control.

Medulla oblongata

The inferior portion of the brainstem that relays sensory information to the thalamus and regulates autonomic functions such as HR, BP, and digestion.

Ventricles

Chambers within the brain formed from the neural tube, including the lateral, third, and fourth ventricles, lined by ependymal cells.

Interventricular foramen

The opening through which the third ventricle communicates with each lateral ventricle.

Cerebral aqueduct

The structure that connects the third ventricle to the fourth ventricle.

Falx cerebri

A dural fold that projects between the cerebral hemispheres and contains the superior and inferior sagittal sinuses.

Tentorium cerebelli

A dural fold that separates the cerebral hemispheres from the cerebellum and contains the transverse sinus.

Arachnoid mater

A spider-web-like membrane providing a smooth surface over the brain, separated from the pia mater by the subarachnoid space.

Pia mater

The innermost meningeal layer that sticks closely to the brain surface, anchored by astrocytes, and contains cerebral blood vessels.

Choroid plexus

An area within each ventricle where ependymal cells produce and secrete cerebrospinal fluid (CSF).

Arachnoid villi

Fingerlike extensions of the arachnoid membrane that penetrate the dura mater to reabsorb CSF; in adults, these form large arachnoid granulations.

Hydrocephalus

A condition caused by problems with CSF reabsorption in infancy, resulting in expanded skulls in babies and potential brain damage in adults.

Blood brain barrier (BBB)

A barrier formed by capillary endothelial cells and supported by astrocytes that restricts the movement of substances into the brain; only lipid-soluble compounds like $O_2$, $CO_2$, and glucose can diffuse across.

Superior colliculi

Sensory nuclei in the midbrain tectum that receive visual inputs and control reflex movements of the eyes, head, and neck in response to visual stimuli.

Inferior colliculi

Sensory nuclei in the midbrain tectum that receive auditory input and control reflex movements in response to loud noises.

Substantia nigra

Midbrain neurons that release dopamine; their loss of activity is a characteristic of Parkinson’s disease.

Purkinjie cells

Highly branched cerebellar cells with extensive dendrites that can receive up to $200{,}000$ synapses, processing motor command information.

Pineal gland

An endocrine structure in the epithalamus that secretes melatonin to regulate day-night cycles.

Limbic system

A functional grouping of brain regions that establishes emotional states, facilitates memory storage, and links conscious functions with unconscious ones.

Hippocamus

A region of the limbic system important for learning and the storage and retrieval of new long-term memories.

Amygdaloid body

A part of the limbic system that regulates HR, controls the 'fight/flight' response, and links emotions with specific memories.

Basal nuclei

Internal brain structures involved with subconscious control of skeletal muscle tone and coordination of learned movement patterns like walking.

Corpus callosum

A bundle of white matter axons that interconnects the two cerebral hemispheres.

Wernicke’s area

A specialized integrative center associated with language comprehension and personality integration.

Broca’s area

A specialized integrative center associated with speech production that regulates breathing and vocalization patterns.

Prefrontal cortex

The anterior part of the frontal lobe responsible for abstract intellectual functions like predicting consequences; it is not fully developed until the early $20\text{s}$.

Alpha waves

EEG waves seen in healthy, awake adults resting with eyes closed; they disappear during sleep or concentration.

Beta waves

High-frequency EEG waves occurring when a person is concentrating on a task, under stress, or in a state of psychological tension.

Theta waves

EEG waves most often observed in children and frustrated adults; may indicate the presence of a brain disorder like a tumor.

Delta waves

Large amplitude, low frequency EEG waves normally seen during deep sleep; in awake adults, they may indicate vascular blockages or brain damage.

Olfactory Nerves (I)

The only cranial nerves directly attached to the cerebrum, responsible for the sense of smell.

Optic Nerves (II)

Sensory cranial nerves responsible for vision that originate in the retina and meet at the optic chiasm.

Trigeminal Nerves (V)

The largest cranial nerves, carrying both sensory and motor information for the face and mastication muscles.

Vagus Nerves (X)

Mixed cranial nerves widely distributed in the thorax and abdomen; damage is commonly associated with difficulty swallowing.

Bell’s palsy

A condition characterized by facial muscle paralysis and loss of taste, caused by viral inflammation of the Facial Nerves (VII).

Tic douloureux

A painful condition affecting the maxillary and mandibular areas, triggered by contact with the lip, tongue, or gums, associated with the Trigeminal Nerves (V).