The Nervous System Review

Comprehensive practice flashcards covering nervous system anatomy, neurophysiology, sensory systems, and neurological disorders based on the review lecture notes.

What are the three primary functions of the nervous system?

Sensory input (monitoring stimuli), integration (processing and interpreting sensory information), and motor output (activating effector organs to cause a response).

What are the two anatomical structures that compose the Central Nervous System (CNS)?

The brain and the spinal cord.

What are the two major cell types found in nervous tissue?

Neurons (nerve cells that transmit electrical signals) and neuroglia (supporting cells that protect, insulate, and support neurons).

Which four types of neuroglia are located in the Central Nervous System (CNS)?

Astrocytes, microglia, ependymal cells, and oligodendrocytes.

Which two types of neuroglia are found in the Peripheral Nervous System (PNS)?

Schwann cells and satellite cells.

What is the function of the myelin sheath and which cells produce it?

It provides a fatty, insulating covering around axons that increases the speed of nerve impulse transmission; it is produced by oligodendrocytes in the CNS and Schwann cells in the PNS.

What is a Node of Ranvier?

A gap or indentation in the myelin sheath along the length of an axon.

What are the major structural parts of a neuron?

Cell body, nucleus, dendrites, axon, myelin sheath, and axon terminals.

What is the functional difference between dendrites and an axon?

Dendrites conduct incoming electrical impulses toward the cell body, whereas the axon conducts impulses away from the cell body toward the axon terminals.

What is a synapse?

The junction across which a nerve impulse is transmitted from the axon terminal of one neuron to another neuron or an effector cell.

What are the three functional types of neurons?

Sensory neurons (carry impulses from sensory receptors to the CNS), interneurons (connect sensory and motor pathways within the CNS), and motor neurons (carry impulses from the CNS to effectors).

What is the difference between irritability and conductivity in nerve tissue?

Irritability is the capacity of a neuron to respond to a stimulus and convert it into a nerve impulse; conductivity is the ability to transmit that impulse to other neurons, muscles, or glands.

What is resting potential in a neuron?

The polarized electrical state of a neuron's plasma membrane when it is not conducting an impulse, characterized by a net positive charge outside and a net negative charge inside.

What occurs during depolarization and repolarization of a neuron?

Depolarization occurs when inward ion flow reverses the membrane polarity; repolarization restores the original resting electrical condition of the membrane.

What is the 'all-or-none response' of an action potential?

The principle that if a stimulus reaches the required threshold, an action potential will fire and propagate at full strength along the entire axon; if the threshold is not reached, no action potential fires at all.

Why is a nerve impulse considered an electrochemical event?

It is electrical because it relies on the movement of charged ions across the membrane to generate an action potential, and chemical because neurotransmitters carry the signal across the synapse between cells.

What are the five essential elements of a reflex arc?

Receptor, sensory neuron, integration center, motor neuron, and effector.

What structural difference distinguishes grey matter from white matter in the CNS?

White matter consists predominantly of dense collections of myelinated fiber tracts, whereas grey matter consists of unmyelinated fibers, cell bodies, and dendrites.

What are the four primary lobes of the cerebral cortex?

Frontal lobe, parietal lobe, occipital lobe, and temporal lobe.

What are the three connective tissue wrappings in peripheral nerves, from deep to superficial?

Endoneurium (surrounds individual axons), perineurium (surrounds fascicles/bundles of axons), and epineurium (surrounds the entire nerve).

What are the five sensory receptor types listed in the nervous system review?

Nocioreceptor, thermoreceptor, mechanoreceptor, photoreceptor, and chemoreceptor.

What stimuli do nocioreceptors, thermoreceptors, and mechanoreceptors detect?

Nocioreceptors detect pain or tissue damage, thermoreceptors detect temperature changes, and mechanoreceptors detect physical deformation caused by touch, pressure, vibration, or stretch.

What is the blind spot of the eye?

The area on the retina corresponding to the optic disc where the optic nerve leaves the eyeball, containing no photoreceptor cells.

What is a Snellen chart used to measure?

Visual acuity, evaluated by reading standardized lines of letters at a designated distance.

What are papillae and what structures do they house?

Small peg-like projections located on the surface of the tongue that contain taste buds.

What are the five basic taste sensations detected by gustatory chemoreceptors?

Sweet, sour, salty, bitter, and umami.

What is a cochlear implant?

A surgically implanted electronic device that converts sound into electrical signals to directly stimulate the auditory nerve, bypassing damaged parts of the ear.

What are the two divisions of the Autonomic Nervous System (ANS) and their primary roles?

The sympathetic division (triggers the 'fight or flight' response during emergencies or exercise) and the parasympathetic division (promotes maintenance activities and conserves energy, supporting homeostasis).

What is a concussion in relation to traumatic brain injury (TBI)?

A form of traumatic brain injury caused by a jolt, blow, or impact to the head that temporarily impairs normal brain function.

What is meningitis?

An inflammation of the meninges, the protective connective tissue membranes surrounding the brain and spinal cord.

What is Multiple Sclerosis (MS)?

An autoimmune disorder of the central nervous system in which the body's immune system attacks and destroys the myelin sheaths around nerve fibers.

What is Alzheimer's disease?

A progressive neurodegenerative disorder of the brain resulting in memory loss, cognitive decline, and changes in behavior and personality.

What is Parkinson's disease?

A progressive movement disorder of the central nervous system associated with the degeneration of dopamine-releasing neurons, causing tremors, rigidity, and impaired coordination.

What is a stroke and what is paralysis?

A stroke is an interruption of blood supply to part of the brain causing brain tissue death; paralysis is the loss of motor function and muscle control, commonly resulting from strokes or nerve and spinal cord injuries.