Anatomy and Physiology I Exam Review: Joints, Nervous Tissue, Membrane Potentials, Synapses, and Brain

Comprehensive 100-card vocabulary flashcard set covering joints, nervous tissue, membrane potentials, synaptic transmission, and brain anatomy from the Anatomy and Physiology I exam review.

Temporomandibular Joint (TMJ)

The synovial articulation between the condyle of the mandible and the mandibular fossa of the temporal bone.

Articular Disc of the TMJ

A pad of fibrocartilage that divides the synovial cavity of the temporomandibular joint into superior and inferior chambers.

Lateral Ligament of the TMJ

A supporting ligament of the temporomandibular joint that prevents posterior displacement of the mandible.

Sphenomandibular Ligament

A supporting ligament located on the medial side of the temporomandibular joint.

Glenohumeral Joint

The humeroscapular joint formed by the hemispherical head of the humerus articulating with the shallow glenoid cavity of the scapula; the most freely mobile joint in the body.

Glenoid Labrum

A fibrocartilage ring that deepens the shallow glenoid cavity of the scapula.

Rotator Cuff

A supportive structure formed by the fused tendons of the supraspinatus, infraspinatus, teres minor, and subscapularis muscles, providing most of the shoulder joint's stability.

Shoulder Separation

A joint dislocation of the clavicle from the scapula at the acromioclavicular joint, typically caused by a blow to the superior shoulder that forces the acromion inferiorly.

Humeroulnar Joint

A hinge articulation of the elbow where the trochlea of the humerus joins the trochlear notch of the ulna.

Humeroradial Joint

An articulation of the elbow where the capitulum of the humerus meets the head of the radius.

Proximal Radioulnar Joint

A pivot joint in the elbow region where the radial head fits into the radial notch of the ulna, rotating like a wheel during pronation and supination.

Annular Ligament

A ligament that encircles and holds the head of the radius securely within the radial notch of the ulna at the proximal radioulnar joint.

Coxal Joint

The hip joint, formed where the hemispherical head of the femur inserts into the deep acetabulum of the coxal (hip) bone.

Round Ligament (Ligamentum Teres)

A ligament of the hip that attaches the fovea capitis on the femoral head to the acetabulum and contains an artery supplying blood to the femoral head.

Tibiofemoral Joint

The hinge joint formed between the femur and the tibia; recognized as the largest and most complex diarthrosis in the human body.

Menisci of the Knee

Medial and lateral shock-absorbing cartilages located within the knee joint cavity that are joined together by the transverse ligament.

Anterior Cruciate Ligament (ACL)

An intracapsular ligament of the knee that crosses deep within the joint and prevents hyperextension.

Posterior Cruciate Ligament (PCL)

An intracapsular ligament of the knee that prevents posterior displacement of the tibia relative to the femur.

Osteoarthritis (OA)

The most common wear-and-tear form of arthritis, marked by softening and degeneration of articular cartilage and the formation of painful bone spurs on exposed bone.

Rheumatoid Arthritis (RA)

An autoimmune attack against joint tissues in which rheumatoid-factor antibodies attack the synovial membrane, causing enzymes to degrade cartilage and the joint to ossify.

Central Nervous System (CNS)

The primary division of the nervous system consisting entirely of the brain and the spinal cord.

Peripheral Nervous System (PNS)

The division of the nervous system consisting of all nerves and ganglia situated outside of the brain and spinal cord.

Autonomic Nervous System (ANS)

The visceral motor division of the nervous system that unconsciously regulates glands, cardiac muscle, and smooth muscle.

Interneuron

A functional class of neuron located entirely within the CNS that processes signals, makes decisions, and accounts for approximately $90\%$ of all neurons.

Neurosoma

The cell body of a neuron (also called soma or perikaryon) containing the nucleus, mitochondria, lysosomes, Golgi complex, inclusions, and rough endoplasmic reticulum.

Chromatophilic Substance

Dark-staining, compartmentalized rough endoplasmic reticulum found within the cytoplasm of a neuron cell body.

Dendrite

A branched extension of the neurosoma that serves as the primary site for receiving incoming signals from other neurons.

Axon Hillock

The conical mound on one side of the neurosoma from which the axon (nerve fiber) originates.

Multipolar Neuron

A structural class of neuron possessing one axon and multiple dendrites, representing the most common type found in the CNS.

Bipolar Neuron

A structural neuron class possessing one axon and one dendrite, found in olfactory cells, retinal neurons, and sensory neurons of the ear.

Unipolar Neuron

A structural neuron class featuring a single short process leaving the soma that branches into peripheral and central axon processes.

Anaxonic Neuron

A structural neuron class that possesses multiple dendrites but no axon, found in the brain, retina, and adrenal gland.

Anterograde Transport

Axonal transport moving organelles, enzymes, and materials away from the neurosoma toward the axon terminal.

Retrograde Transport

Axonal transport moving materials, recycled vesicles, or pathogens from the axon terminal back toward the neurosoma.

Kinesin

The motor protein that utilizes ATP to drive anterograde transport along axonal microtubules.

Dynein

The motor protein that utilizes ATP to drive retrograde transport along axonal microtubules toward the neurosoma.

Oligodendrocyte

A central nervous system glial cell whose processes wrap around portions of multiple nearby axons to form myelin sheaths.

Ependymal Cell

A central nervous system glial cell lining the brain ventricles and spinal cord central canal that produces, secretes, and circulates cerebrospinal fluid.

Microglia

Small, phagocytic macrophages in the CNS that engulf cellular debris, waste products, and pathogens.

Astrocyte

The most abundant glial cell in the CNS; it contacts capillaries with perivascular feet to help form the blood-brain barrier, regulates blood flow, provides lactate, and forms scar tissue.

Schwann Cell (Neurolemmocyte)

A peripheral nervous system glial cell that wraps repeatedly around a segment of a single axon to form myelin and assists in damaged nerve fiber regeneration.

Neurilemma

The thick outermost coil of the Schwann cell surrounding a PNS axon, containing the nucleus and most of the cytoplasm.

Nodes of Ranvier

The unmyelinated gaps along an axon located between adjacent internodal segments of myelin sheath.

Trigger Zone

The physiological region consisting of the axon hillock and initial segment where voltage-gated ion channels are concentrated and action potentials are initiated.

Resting Membrane Potential (RMP)

The electrical charge difference across the plasma membrane of an unstimulated cell, typically around $-70\,\text{mV}$ in a resting neuron.

Chemically Gated Channel

A transmembrane ion channel that opens or closes when a specific chemical ligand (such as a neurotransmitter) binds to its receptor.

Voltage-Gated Channel

An ion channel that opens or closes in response to shifts in the electrical membrane potential across the plasma membrane.

Mechanically Gated Channel

An ion channel that opens in response to physical deformation of the membrane, such as touch, pressure, or vibration.

Sodium-Potassium ($\text{Na}^+/\text{K}^+$) Pump

An active transport carrier protein that expends ATP to transport $3\,\text{Na}^+$ out of the cell for every $2\,\text{K}^+$ moved in, contributing about $-3\,\text{mV}$ to RMP.

Local Potential

A localized, temporary fluctuation in membrane potential that is graded in magnitude, decremental with distance, and reversible.

Depolarization

A shift in membrane potential toward a less negative or positive voltage, typically caused by the inward diffusion of $\text{Na}^+$ ions.

Hyperpolarization

A shift in membrane potential making the intracellular side more negative than normal resting membrane potential.

Threshold

The minimum membrane potential (approximately $-55\,\text{mV}$) required at the trigger zone to open voltage-gated channels and initiate an action potential.

Action Potential (AP)

A rapid, nondecremental, all-or-none voltage reversal along a membrane driven by the sequential opening and closing of voltage-gated ion channels.

Absolute Refractory Period

The period during an action potential when voltage-gated $\text{Na}^+$ channels are inactivated, preventing any subsequent action potential from firing regardless of stimulus strength.

Relative Refractory Period

The phase during membrane hyperpolarization when voltage-gated $\text{K}^+$ channels remain open, requiring a stronger-than-normal stimulus to reach threshold.

Continuous Conduction

The uninterrupted mode of signal transmission along unmyelinated axons where action potentials are regenerated continuously along the entire length of the fiber.

Saltatory Conduction

The rapid mode of nerve impulse conduction along myelinated axons in which electrical current spreads passively beneath myelin and action potentials jump from node to node.

Type A Fiber

A large-diameter, myelinated nerve fiber that conducts signals at speeds up to approximately $120\,\text{m/s}$, carrying somatic sensory and skeletal motor information.

Type C Fiber

A small-diameter, unmyelinated nerve fiber that conducts slowly at approximately $1\,\text{m/s}$, carrying autonomic motor commands to involuntary effectors.

Electrical Synapse

A synapse where adjacent cell membranes are linked directly by gap junctions (connexons), enabling fast, delay-free ion flow but preventing complex information integration.

Chemical Synapse

A synapse where communication occurs across a $20\,\text{nm}$ synaptic cleft through the regulated release, diffusion, and receptor binding of neurotransmitter molecules.

Synaptic Delay

The brief time interval (approximately $0.2\text{--}0.5\,\text{ms}$) required for neurotransmitter release, diffusion across the cleft, and binding to postsynaptic receptors.

Synaptic Fatigue

The temporary exhaustion of synaptic transmission occurring under intense stimulation when neurotransmitter stores are depleted faster than they can be resynthesized.

Acetylcholine (ACh)

A neurotransmitter formed from acetic acid and choline that binds ligand-gated $\text{Na}^+$ channels at excitatory cholinergic synapses.

Monoamines

A family of neurotransmitters synthesized from amino acids, including serotonin from tryptophan, and catecholamines (epinephrine, norepinephrine, dopamine) from tyrosine.

Acetylcholinesterase (AChE)

An enzyme located in the synaptic cleft that terminates transmission by hydrolyzing acetylcholine into acetate and choline.

Excitatory Postsynaptic Potential (EPSP)

A graded depolarizing local potential in the postsynaptic membrane that shifts voltage toward threshold, typically caused by $\text{Na}^+$ entry.

Inhibitory Postsynaptic Potential (IPSP)

A graded hyperpolarizing local potential in the postsynaptic membrane that moves voltage away from threshold, commonly caused by $\text{Cl}^-$ influx or $\text{K}^+$ efflux.

Temporal Summation

The combining of postsynaptic potentials occurring when a single presynaptic neuron fires in rapid succession, adding together before earlier potentials decay.

Spatial Summation

The additive effect produced when multiple separate presynaptic neurons release neurotransmitter simultaneously at different synapses across the postsynaptic cell.

Presynaptic Facilitation

A process in which an axoaxonic neuron enhances neurotransmitter release from another neuron, such as by using serotonin to keep voltage-gated $\text{Ca}^{2+}$ channels open longer.

Presynaptic Inhibition

A mechanism in which an axoaxonic neuron suppresses transmission from another neuron by releasing GABA, preventing voltage-gated $\text{Ca}^{2+}$ channels from opening.

Labeled-Line Code

A neural coding mechanism where the modality or type of sensory stimulus is determined strictly by which specific nerve fibers transmit action potentials to the CNS.

Multiple Sclerosis (MS)

An autoimmune disorder characterized by the progressive deterioration of central nervous system myelin and oligodendrocytes, replacing myelin with hardened scar tissue.

Tay-Sachs Disease

A hereditary lysosomal storage disorder marked by the abnormal accumulation of ganglioside glycolipids, which impairs nerve signal conduction.

Guillain-Barré Syndrome

An acute peripheral nervous system demyelinating autoimmune disorder, frequently triggered by a preceding viral infection.

Regeneration Tube

A structural pathway formed by the Schwann cell neurilemma, endoneurium, and basal lamina that guides a sprouting damaged PNS axon toward its target.

Corpus Callosum

A thick, prominent band of myelinated nerve fibers located at the base of the longitudinal cerebral fissure that connects the right and left cerebral hemispheres.

Longitudinal Cerebral Fissure

The prominent deep vertical groove separating the right and left cerebral hemispheres.

Gyri

Thick, rounded surface folds or ridges covering the cerebral cortex and cerebellum.

Sulci

Shallow depressions or grooves on the brain surface located between adjacent gyri.

Dura Mater

The tough, outermost cranial meninx consisting of an outer periosteal layer and an inner meningeal layer.

Falx Cerebri

A vertical fold of the cranial meningeal dura mater that projects into the longitudinal cerebral fissure between the cerebral hemispheres.

Subarachnoid Space

The anatomical space between the arachnoid mater and the pia mater that contains circulating cerebrospinal fluid and blood vessels.

Choroid Plexus

A spongy network of blood capillaries situated on the floor of each brain ventricle, lined by ependymal cells that filter blood to produce CSF.

Cerebral Aqueduct

A slender canal passing through the midbrain that connects the third ventricle to the fourth ventricle.

Cerebrospinal Fluid (CSF)

A clear, colorless filtrate filling ventricles and subarachnoid space that provides buoyancy, shock absorption, and chemical stability to the CNS.

Arachnoid Granulations

Cauliflower-like extensions of the arachnoid mater protruding into the superior sagittal sinus to reabsorb CSF into the venous bloodstream.

Blood-Brain Barrier (BBB)

A protective barrier shielding brain capillaries, composed of tight junctions between vascular endothelial cells induced by astrocyte perivascular feet.

Blood-CSF Barrier

A selective physiological barrier located at the choroid plexuses formed by tight junctions between ependymal cells.

Ischemic Stroke

A cerebrovascular accident caused by a sudden interruption of cerebral blood flow due to an arterial obstruction, such as a thrombus or lipid deposit.

Hemorrhagic Stroke

A cerebrovascular accident resulting from the rupture of a cerebral or subarachnoid blood vessel, leaking blood into brain tissue.

Medulla Oblongata

The most caudal brainstem region, derived from embryonic myelencephalon, containing autonomic centers controlling heart rate, blood pressure, respiration, and visceral reflexes.

Pons

The brainstem structure derived from embryonic metencephalon containing apneustic and pneumotaxic respiratory centers, pontine nuclei, and nuclei for cranial nerves V through VIII.

Tectum

The posterior, roof-like region of the midbrain located dorsal to the cerebral aqueduct, containing the superior and inferior colliculi.

Superior Colliculi

The upper pair of midbrain tectal nuclei responsible for visual attention, tracking moving targets, and visual reflexes.

Inferior Colliculi

The lower pair of midbrain tectal nuclei that relay auditory signals from the inner ear and mediate auditory reflexes.

Substantia Nigra

A melanin-pigmented nucleus of the midbrain that releases inhibitory motor signals to the thalamus and basal nuclei, degenerating in Parkinson's disease.

Reticular Activating System (RAS)

A specialized midbrain component of the reticular formation that regulates alertness, attentiveness, and sensory habituation by modulating cerebral cortex activity.