Nervous System Anatomy, Physiology, and Disorders

Comprehensive practice flashcards detailing neuron anatomy, cellular transmission, brain and spinal cord structures, autonomic nervous system pathways, and clinical nervous system disorders.

Neuron

The basic structural unit of the nervous system that coordinates body activities and enables the body to respond and adapt to internal and external changes.

Soma

The cell body and control center of the neuron containing the nucleus.

Nucleus

The structure that controls the neuron.

Dendrites

Nerve fibers that act as receivers, carrying impulses (action potentials) toward the cell body.

Axon

A nerve fiber that moves signals and sends messages by carrying impulses (action potentials) away from the cell body.

Myelin Sheath

A protective lipid coating wrapped around much of the axon that insulates and maintains the axon while increasing impulse transmission speed up to $\sim 268\,\text{mph}$.

Terminal Buttons

Structures located at the axon terminal that transmit signals across the synapse to other neurons.

Synapse

The space between the axon of one neuron and the dendrites of another neuron.

Synaptic Cleft

The microscopic fluid-filled space between the presynaptic membrane and the postsynaptic membrane through which neurotransmitters travel.

Neurotransmitters

Special chemicals located at the end of each axon that are required for nerve impulses to pass from one neuron to another.

Excitatory Neurotransmitters

Neurotransmitters that help a neuron propagate a nerve impulse.

Inhibitory Neurotransmitters

Neurotransmitters that reduce the likelihood of a neuron propagating a nerve impulse.

Acetylcholine

A neurotransmitter that is necessary for muscle contraction.

Dopamine

A neurotransmitter that modulates mood and plays a significant role in positive reinforcement and dependency.

Glutamate

A neurotransmitter associated with learning and memory.

Epinephrine

A neurotransmitter regulating attention and mental focus; elevated levels correlate with sleep problems, anxiety, and ADHD, while decreased levels correlate with fatigue and inability to focus.

Serotonin

A neurotransmitter that helps to regulate sleep and mood.

Sensory Nerves

Nerves that carry messages from all parts of the body to the brain and spinal cord.

Motor Nerves

Nerves that carry messages from the brain and spinal cord to muscles and glands.

Associative Nerves

Nerves that carry both sensory and motor messages.

Central Nervous System (CNS)

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

Peripheral Nervous System (PNS)

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

Autonomic Nervous System

The division of the nervous system that controls involuntary body functions.

Sympathetic Nervous System

The autonomic division that prepares the body for fight or flight by increasing heart rate, respirations, and blood pressure while decreasing digestive activity.

Parasympathetic Nervous System

The autonomic division that restores homeostasis by decreasing heart rate, respirations, and blood pressure while increasing digestive activity.

Homeostasis

The balanced internal state maintained by the sympathetic and parasympathetic systems working together to control involuntary functions at proper rates.

Cerebrum

The highest and largest section of the brain; separated into lobes, it governs reasoning, thought, memory, speech, sensation, sight, smell, hearing, and voluntary movements.

Frontal Lobe

The cerebral lobe responsible for memory formation, emotions, personality, decision-making, and logic.

Broca's Area

A functional area in the left frontal lobe that controls facial neurons, speech production, and language comprehension.

Broca's Aphasia

A speech impairment condition where comprehension remains intact, but the motor ability to speak or articulate words is significantly decreased.

Parietal Lobe

The cerebral lobe responsible for sensory integration, spatial awareness, and perception.

Temporal Lobe

The cerebral lobe responsible for hearing, language organization/comprehension, and memory retrieval and formation.

Wernicke's Area

A functional area situated in the left temporal lobe that controls language comprehension.

Wernicke's Aphasia

A disorder in which language comprehension is inhibited; spoken words and sentences are not understood, and sentence production may become nonsensical.

Occipital Lobe

The cerebral lobe dedicated to the processing, integration, and interpretation of visual stimuli.

Cerebellum

Brain structure positioned below the back of the cerebrum; coordinates muscle activity, balance, posture, and muscle tone.

Corpus Callosum

A broad band of nerve fibers connecting the cerebral hemispheres that allows communication between both sides of the brain.

Pons

A section of the brainstem that conducts messages to other parts of the brain and oversees reflex actions such as chewing, tasting, and saliva production.

Medulla Oblongata

The lowest section of the brainstem connecting with the spinal cord; regulates heartbeat, respiration, swallowing, coughing, and blood pressure.

Hypothalamus

Brain structure that regulates the autonomic nervous system, temperature, appetite, sleep, water balance, blood vessel dilation/constriction, and emotional responses like fear, anger, and pleasure.

Spinal Cord

Nerve pathway extending downward from the medulla oblongata to the $1\text{st}$ or $2\text{nd}$ lumbar vertebrae; carries sensory and motor impulses and mediates reflex actions.

Meninges

A three-layered set of protective membranes covering and shielding the brain and spinal cord.

Dura Mater

The thick, tough outer membrane layer of the meninges.

Arachnoid Membrane

The delicate, weblike middle membrane layer of the meninges.

Pia Mater

The innermost meningeal layer closely attached to the brain and spinal cord, containing blood vessels that supply nutrients to nerve tissue.

Ventricles

Interconnected hollow spaces within the brain that connect with the subarachnoid space and produce cerebrospinal fluid.

Cerebrospinal Fluid (CSF)

Fluid produced inside the ventricles that acts as a shock absorber, distributes nutrients, and removes metabolic wastes from the central nervous system.

Epilepsy

A brain disorder marked by abnormal electrical impulses in neurons; produces convulsions, hypersalivation, and loss of consciousness; treated with anticonvulsant medications.

Hydrocephalus

An excessive buildup of CSF in brain ventricles leading to increased pressure and brain damage; presents with an enlarged head and bulging eyes; treated with a surgical shunt into the abdominal cavity.

Meningitis

Inflammation of the meninges and/or spinal cord caused by bacteria, viruses, fungi, or toxins; characterized by high fever, severe headache, and neck stiffness.

Multiple Sclerosis

A chronic, progressive condition caused by degeneration of the myelin sheath in the CNS; typically occurs between ages $20$ and $40$, causing weakness, tremors, visual disturbances, and incontinence.

Neuralgia

Nerve pain caused by inflammation, pressure, toxins, or systemic disease; managed by eliminating the underlying cause.

Parkinson's Disease

A chronic, progressive degeneration of brain cells occurring typically in individuals aged $> 50$ years; symptoms include tremors, muscular rigidity, shuffling gait, drooling, and loss of facial expression.

Hemiplegia

Paralysis affecting only one side of the body, commonly caused by a tumor, injury, or cerebrovascular accident.

Paraplegia

Paralysis involving the lower extremities or lower portion of the body resulting from a spinal cord injury.

Quadriplegia

Paralysis of the arms, legs, and entire body below the site of a spinal cord injury.

Shingles

Acute inflammation of nerve cells caused by the herpes virus along thoracic nerve pathways; manifests as painful fluid-filled vesicles, itching, and fever lasting $1$ to $4$ weeks.

Cerebral Palsy

A motor impairment disorder caused by brain damage or oxygen deprivation to the brain; symptoms include exaggerated reflexes, tense muscles, contractures, and speech impairment.

Cerebrovascular Accident (CVA)

Brain tissue destruction caused by lack of oxygen due to impaired blood flow from a hemorrhage or thrombus; critical interventions during the first $3$ hours can minimize lasting damage.

Encephalitis

Inflammation of brain tissue caused by a virus, bacterium, or chemical agent; the viral variety is frequently transmitted via mosquito bites, such as St. Louis Encephalitis.