Neurological System Flashcards
Dendrites
Receives electrical signals FROM other neurons
Axon
Transmits electrical signal TO other neurons
Glial cells
Supporting cells for functioning of the brain. Three types in CNS are: astrocytes, oligodendrocytes, microglia. One in PNS is: Schwann Cell
Astrocytes
Looks like “stars” surrounding the capillaries of the brain. Nutrient supplier and toxin filter, forms tight junctions with the capillaries. The filtering property is referred to as “blood-brain barrier.”
Schwann cells
Forms supporting structure for nerves (unlike astrocytes, which is for capillary). Myelinated nerves have Schwann cells that wrap around the nerve outside the myelination, and un-myelinated nerves have Schwann cells that do not wrap, but simply support the nerve fiber.
Gray and white matter in terms of myelination
gray = no myelination, white = myelination
Resting Membrane Potential
-70mV, for neurons. Na-K pump maintains this -70mV difference. Na-K pump lets three Na out two K in, so net potential is negative.
Depolarization of neuron
Neuron gets excitory stimulus, and when enough signal causes sodium gates to open (and Na rushes in to depolarize) this occurs. +30mV is reached at the end of depolarization.
Repolarization of neuron
After depolarization, potassium gates open and K gets out to polarize the electrical system. Sodium gates close at the same time.
Hyperpolarization of neuron
After repolarization, potassium gates close and a brief moment where larger than 70mV voltage difference occurs.
Refractory period
Repolarization + hyperpolarization period is referred to as this, since no stimulus can cause the system to react. This period is also necessary to stop electrical signal from traveling the opposite way.
Nodes of Ranvier
Saltatory conduction occurs due to this structure. The myelin sheath prevents normal influx of Na+ and helps propagate signal more efficiently.
Chemical Synapse, Synaptic Cleft
Electrical signal causes release of chemicals (neurotransmitters) which travel through this
Role of Ca++ in Synapse
When action potential reaches the synaptic knob, calcium gates open and let calcium in. Vesicles containing neurotransmitter merge with synaptic knob, releasing the chemicals.
Neurotransmitters
Can be inhibitory or excitatory. K+/Cl- opening will hyperpolarize and thus inhibit. K+/Na+ opening will depolarize and thus excite. Either direct or second messenger stimulation of gated channels can occur.
Ventricles of the Brain
Fluid-filled parts on the brain.
Sulcus, Gyrus
Respectively, parts of the brain that fold inward (valley), parts of the brain that fold outward (trough).
Cerebrum
Contains cortex and corpus callosum, the outer parts of the brain that we normally associate with folding.
Diencephalon
Contains thalamus, pineal body, hypothalamus
Brain stem
Contains midbrain, pons, medulla oblongata
Four lobes of cerebrum
Frontal, occipital, parietal, temporal
Superior frontal gyrus
Located in frontal lobe, located nearest to center and cuts frontal lobe in half vertically. Left and right brain both has superior frontal gyrus.
Central sulcus
Separates the frontal lobe from parietal lobe, cuts entire brain in half horizontally.
Inferior temporal gyrus
Bottom left/right gyrus in brain in temporal lobe
Superior temporal gyrus
This gyrus borders frontal lobe from temporal robe
Hippocampus
Spatial navigation, consolidation of short term memory to long term memory. Located near the midbrain, one on both sides of the brain
Sylvian fissure
Fissure between temporal and frontal brain
Precentral and Postcentraul Gyrus
Motor and sensory information processed (respectively), located near the central sulcus of the frontal brain. Called sensorimotor strip.
Parieto-occipital fissure
Fissure between parietal and occipital lobes
Calcarine fissure
Fissure in the occipital lobe responsible for visual information processing
Cerebellum
Posture, coordination, timing/precision of movements
Brainstem
Respiration, heart function, gastrointestinal motor. Conducts electricity from spinal cord to cerebral cortex. Includes pons, medulla oblongata, and midbrain.
Medulla oblongata
Involuntary functions of the heart, respiratory, and gastrointestinal
Pons
Contain clusters of neurons (is a nuclei) that deal with sleep, respiration, swallowing, bladder control, eye movement, facial sensation, etc. Relays information between cerebellum and cerebral cortex.
Basal ganglia
Located right below the cerebrum, curved shape. Habits, obsessive-compulsive behaviors, addiction, emotional response. Includes globus pallidus, putamen, caudate.
Globus pallidus
Regulates voluntary movements, looks like a disk. Surrounds the thalamus.
Putamen
Regulates voluntary movements, looks like a fruit on a branch (hence the name, from greek origins)
Caudate nucleus
Regulates voluntary movements, looks like a ring
Thalamus
Regulates consciousness, sleep, alertness. Surrounds the mid-brain, two parts on left and right.
Commissural, association, and projection fibers of the white matter
Respectively, axon fibers that connect one cerebral hemisphere to the other, connect one cerebral hemisphere to itself or the basal ganglia, and connect cerebrum and basal ganglia to the spinal cord.
Optic chiasm
Part of the optic nerves that cross each other. Located below cerebrum, in front of midbrain. Can be seen as fibers behind eyes that cross like an X.
Cerebrospinal fluid
Provides buoyancy to brain to prevent blocking of blood vessels, cushions cortex from damage, protects cortical neurons from toxins through cleansing of this
CSF Flow
Generated in choroid plexus of lateral ventricle (the ventricle most near the center of the brain), into 3rd ventricle (below the lateral ventricle), then into 4th ventricle located way below 3rd ventricle. Flows through the rest of the brain below skull and below superior sagittal sinus, in subarachnoid space. Absorbed over time into venous blood of superior sagittal sinus.
Aqueduct of Sylvius
Connects 3rd and 4th ventricle, shows as small opening at the center of the brain in MRI scans.
Brain coverings
From outside to inside, skull, dura mater, arachnoid, pia mater. Arachnoid is filled with spider-like projections.
Spinal cord composition
White matter for communication with the brain, gray matter for reflex arc. Dorsal (back) and ventral (front) roots connect to spinal cord, conveys sensory and motor information, respectively (like how precentral gyrus is in front and controls motor, and how postcentral gyrus controls sensory).
Infundibulum
Stalk that connects to pituitary gland
Three types of three-neuron reflex arcs
Ipsilateral (motor and sensory from same side of the body), contraleteral (sensory ennervates motor on the other side of the body), intersegmental (sensory ennervates motor on different columns of spine)
Locations of major autonomic pathways
Sympathetic: influences the body with nerves from the thoracic (upper five spines) and lumbar levels (bottom spines) of the spinal cord. Usually accompanied by ganglia parallel to the spine. Parasympathetic: influences the body with nerves from the brain stem (vagus nerves) and nerves from the sacral (“tail bone”) regions.
Cranial X nerve
Another name for vagus nerve, which is primarily motor/sensory nerve for autonomic parasympathetic system.
