Neuroscience: Nervous System Functions, Neurons, and Brain Structures

Information reception

Nervous system receives information from internal and external environments.

Information processing

Nervous system processes information and determines a response.

Command output

Nervous system issues commands to cells to carry out responses.

Neuronal excitability

Neurons respond to stimuli.

Neuronal conductivity

Neurons produce and carry electrical signals.

Neuronal secretion

Neurons release neurotransmitters when signals reach nerve fiber endings.

Sensory signaling

Sensory neurons conduct signals from receptors to the CNS.

Motor signaling

Motor neurons conduct signals from the CNS to effectors.

Interneuron processing

Interneurons process information within the CNS.

Myelination

Support cells form myelin around certain nerve fibers.

CNS myelination

Oligodendrocytes form myelin in the CNS.

PNS myelination

Schwann cells form myelin in the PNS.

Signal conduction in myelinated fibers

Myelin changes how quickly and efficiently signals travel.

Synaptic transmission

Presynaptic neuron releases neurotransmitter across synaptic cleft to affect postsynaptic neuron.

Neurotransmitter release

Synaptic vesicles release chemical messengers at the axon terminal.

Axodendritic signaling

Signal passes from axon to dendrite.

Axosomatic signaling

Signal passes from axon to cell body.

Axoaxonic signaling

Signal passes from axon to axon.

Diverging circuit process

One input spreads to multiple outputs.

Converging circuit process

Multiple inputs combine into one output.

Reverberating circuit process

Signal cycles repeatedly through a circuit.

Parallel after-discharge process

Signal travels through parallel pathways and produces a delayed/prolonged output.

Spinal cord conduction

Spinal cord carries information up and down the body.

Spinal neural integration

Multiple neurons integrate information into circuits to evaluate responses.

Locomotion regulation

Spinal circuits regulate repeated movement patterns.

Reflex process

A stimulus triggers an involuntary programmed response.

Autonomic reflex process

Reflex affects internal organs.

Somatic reflex process

Reflex affects skeletal muscles.

Patellar reflex process

Stimulus at patellar ligament sends sensory signal to spinal cord, then motor signal activates quadriceps.

Stretch reflex

A muscle responds to stretching by contracting.

Flexor reflex

A painful stimulus causes withdrawal from the stimulus.

Crossed extension reflex

One side withdraws while the opposite side extends for support.

Tendon reflex

Reflex response protects muscles and tendons from excessive tension.

CSF production

Choroid plexus secretes cerebrospinal fluid.

CSF flow

CSF moves from lateral ventricles through the third and fourth ventricles, then into the subarachnoid space.

CSF reabsorption

CSF is reabsorbed into venous blood at arachnoid granulations.

Brain protection by CSF

CSF bathes and cushions the brain and spinal cord.

Frontal lobe processing

Supports planning, decision making, emotional control, voluntary motor control, and speech production.

Parietal lobe processing

Supports somatic sensation, sensory integration, spatial perception, language processing, and numerical awareness.

Occipital lobe processing

Supports visual awareness and visual processing.

Temporal lobe processing

Supports hearing, smell, emotion, learning, memory consolidation, and language comprehension.

Insula processing

Supports taste, pain, visceral sensation, consciousness, emotion/empathy, and cardiovascular homeostasis.

Limbic system processing

Supports emotion and memory-related functions.

Basal nuclei processing

Involved in deep brain motor-related functions.

Sensory detection

Receptors detect specific sensory information.

Free nerve ending detection

Detects pain, heat, and cold.

Tactile disc detection

Detects light touch and pressure.

Hair receptor detection

Detects light touch and movement of hairs.

Tactile corpuscle detection

Detects light touch and texture.

Bulbous corpuscle detection

Detects heavy continuous touch/pressure and joint movement.

Lamellar corpuscle detection

Detects deep pressure, stretch, tickle, and vibration.

Muscle spindle detection

Detects muscle tension for proprioception.

Tendon organ detection

Detects tendon tension for proprioception.

Receptive field processing

Smaller receptive fields allow more precise sensation; larger fields are less precise.

Referred pain process

Pain from an internal organ is perceived in another body region.

Taste detection

Taste cells detect taste stimuli through taste hairs and taste pores.

Taste signal transmission

Sensory nerve fibers carry taste information from taste buds.

Smell detection

Odor molecules interact with olfactory hairs in the olfactory mucosa.

Smell signal transmission

Olfactory information travels through olfactory nerve fascicles to the olfactory bulb and tract.

Hearing process

Ear structures transmit sound information toward the cochlear nerve.

Equilibrium process

Vestibular structures help detect body position and movement.

Rod function

Rods detect low light and support night vision.

Cone function

Cones detect color and support high-acuity day vision.

Day vision process

Cones function best in bright light and allow color/high-detail vision.

Night vision process

Rods function best in low light but provide lower acuity.

Ménière disease process

Disorder causes episodes of vertigo, nausea, tinnitus, ear pressure, and progressive hearing loss.

Ageusia process

Taste modality is lost.

Color blindness process

Lack of one cone type reduces ability to distinguish certain colors.

Paresthesia process

Abnormal sensations occur without stimulation.

Tinnitus process

Imaginary sounds are perceived without an external sound source.

Transport function

Blood transports materials through the body.

Protection function

Blood contributes to body defense.

Regulation function

Blood helps regulate body conditions.

Blood typing

Blood is classified by ABO type and Rh factor.

ABO blood type process

Blood type depends on surface molecules shown for type A, B, AB, or O.

Rh classification

Blood is classified as Rh positive or Rh negative.

Embolism process

An abnormal object travels through the bloodstream.

Embolism danger process

Embolus can block vessels and stop blood flow to vital tissues.

DIC process

Widespread clotting occurs inside unbroken vessels.

DIC damage process

Widespread clotting can lead to hemorrhage, vessel congestion, and tissue necrosis.

Hemophilia process

Deficiency of clotting factor causes abnormally slow clotting.

Infectious mononucleosis process

Epstein-Barr virus infects B lymphocytes.

Septicemia process

Bacteria enter and circulate in the bloodstream.

Sickle-cell disease process

Red blood cells become abnormally sickle-shaped.

Pulmonary circulation

Blood moves between heart and lungs.

Systemic circulation

Blood moves between heart and body tissues.

One-way blood flow

Heart valves keep blood moving forward and prevent backflow.

Right heart flow

Body blood enters right atrium, moves to right ventricle, then goes to lungs.

Lung gas exchange in circulation

Blood unloads CO₂ and loads O₂ in lungs.

Left heart flow

Oxygen-rich blood returns to left atrium, moves to left ventricle, then exits through aorta.

Complete heart blood flow

Venae cavae → right atrium → right ventricle → pulmonary trunk → lungs → pulmonary veins → left atrium → left ventricle → aorta.

SA node firing

Pacemaker initiates heartbeat excitation.

Atrial excitation

Excitation spreads through atrial myocardium.

AV node firing

AV node continues conduction after atrial excitation.

Ventricular conduction

Excitation travels down AV bundle and through subendocardial conducting network.

Ventricular contraction coordination

Conducting network distributes excitation through ventricular myocardium.

Aging heart process

Arteries stiffen, heart works harder, valves thicken/calcify, and pumping weakens.

Cardiac tamponade process

Fluid or clotted blood compresses heart and reduces filling/output.

Cardiomyopathy process

Myocardial disease causes wall changes, dilation, or failure.

Congestive heart failure process

One ventricle fails to pump as much as the other, causing blood accumulation and edema.