Anatomy and Physiology of the Brain and Nervous System

Comprehensive flashcards covering cerebrospinal fluid flow, the blood-brain barrier, brain divisions, diencephalon structures, cerebral lobes, cerebral tracts, and the limbic system.

Formation and Flow of Cerebrospinal Fluid (CSF)

The pathway wherein CSF is secreted by the choroid plexuses in the lateral, third, and fourth ventricles, circulates into the central canal and subarachnoid space around the brain and spinal cord, and is reabsorbed into the venous bloodstream through arachnoid villi into the dural sinuses.

Choroid Plexus

A vascular structure located in each ventricle of the brain that secretes cerebrospinal fluid (CSF), with its pulsations aiding in fluid circulation.

Arachnoid Villi

Projections of the arachnoid mater into the dural sinuses through which cerebrospinal fluid is reabsorbed into the venous bloodstream.

Blood-Brain Barrier

A semi-permeable protective membrane formed by tightly joined endothelial cells, a thick basement membrane, and astrocyte feet that restricts harmful substances from passing from the bloodstream into brain tissue fluid.

Enteric Nervous System

A vast network of neurons lining the intestinal tract that functions as a second nervous system and communicates directly with the central nervous system.

Gut-Brain Axis

The bidirectional communication pathway between the enteric nervous system and the central nervous system that incorporates crosstalk from the endocrine and immune systems.

Brainstem

The lowest division of the brain consisting of the midbrain, pons, and medulla oblongata.

Midbrain

The section of the brainstem containing tracts that relay sensory and motor impulses, centers for auditory and visual reflexes, and neuron clusters integral to muscle control.

Pons

The division of the brainstem that conveys signals to and from different brain regions and gives rise to cranial nerves V, VI, VII, and VIII.

Medulla Oblongata

The lowermost part of the brainstem connecting the brain to the spinal cord; houses vital cardiac, vasomotor, and respiratory centers, reflex centers for coughing, sneezing, swallowing, and vomiting, and cranial nerves IX, X, XI, and XII.

Cardiac Center

A vital regulatory center located in the medulla oblongata that regulates heart rate.

Vasomotor Center

A vital regulatory center located in the medulla oblongata that regulates blood pressure by controlling blood vessel diameter.

Cerebellum

The brain structure located behind the brainstem that contains more neurons than the rest of the brain combined, linked to the cerebral cortex by approximately $40\text{ million}$ neurons, and responsible for balance, posture, coordination, and evaluating sensory input.

Diencephalon

A deep brain region residing atop the brainstem, with its chief structures being the thalamus and hypothalamus.

Thalamus

A diencephalic structure shaped like two side-by-side eggs that acts as a sensory gateway and filter for nearly all sensory impulses traveling to the cerebral cortex.

Hypothalamus

A tiny diencephalic region that controls the autonomic nervous system, hunger, thirst, temperature regulation, the pituitary gland, and diverse emotional responses.

Reticular Activating System (RAS)

A component of the reticular formation responsible for maintaining wakefulness and alertness by filtering out insignificant sensory input and dispatching impulses to the cerebral cortex.

Cerebrum

The largest, most obvious division of the brain responsible for thought, memory, emotion, judgment, and voluntary movement.

Lobes of the Cerebrum

The five distinct regions of the cerebrum demarcated by sulci: frontal lobe, parietal lobe, temporal lobe, occipital lobe, and insula.

Frontal Lobe

The cerebral lobe bounded posteriorly by the central sulcus that governs voluntary movements, memory, emotion, social judgment, decision making, reasoning, aggression, and personality aspects.

Parietal Lobe

The cerebral lobe bounded anteriorly by the central sulcus that receives and interprets bodily sensations such as touch, temperature, pressure, pain, and proprioception.

Proprioception

The awareness of one's body and body parts in space and in relation to each other.

Temporal Lobe

The cerebral lobe separated from the parietal lobe by the lateral sulcus that governs hearing, smell, learning, memory, emotional behavior, and visual recognition.

Occipital Lobe

The posterior cerebral lobe concerned with analyzing and interpreting visual information.

Insula

A deep cerebral lobe hidden behind the lateral sulcus that plays a role in pain perception, basic emotions, addiction, motor control, self-awareness, and cognitive functioning.

Tracts

Bundles of myelinated nerve fibers composing the white matter of the cerebrum that convey impulses between regions of the brain and spinal cord.

Corpus Callosum

A large bridge of white matter tracts enabling direct communication between the right and left cerebral hemispheres.

Cerebral Cortex

The thin surface layer of gray matter covering the cerebrum, constituting approximately $40\%$ of total brain mass.

Basal Nuclei

Masses of gray matter situated deep within the cerebral white matter that play an essential role in movement control.

Limbic System

A complex set of structures encircling the corpus callosum and thalamus known as the emotional brain, acting as the primary seat of emotion and learning.

Hippocampus

A key limbic structure charged with converting short-term memories into long-term memories, critical for learning.

Amygdala

Two almond-shaped neural masses positioned on either side of the thalamus involved in processing emotions such as anger, jealousy, and fear, as well as storing and recalling past emotional memories.