Nervous System and Special Senses Study Guide

Vocabulary flashcards covering Chapters 12, 13, and 14 for Nervous System and Special Senses exam review.

Communication

Function of the nervous system that sends messages between the nervous system and other cells/systems.

Control

Function of the nervous system that regulates body functions and helps maintain homeostasis.

Integration

Function of the nervous system that combines information so the body can function as one unit.

Central Nervous System (CNS)

Structural division consisting of the brain and spinal cord; processes information and coordinates responses.

Peripheral Nervous System (PNS)

Structural division consisting of all nervous tissue outside the brain and spinal cord (including cranial nerves and spinal nerves); carries information to and from the CNS.

Somatic Nervous System (SNS)

Functional division with a sensory component that receives information from skin, muscles, joints, and senses, and a motor component that controls skeletal muscles.

Autonomic Nervous System (ANS)

Functional division that controls involuntary functions; includes sympathetic and parasympathetic divisions.

Sympathetic division

Division of the autonomic nervous system that generally prepares the body for activity/stress.

Parasympathetic division

Division of the autonomic nervous system that generally promotes rest and normal maintenance.

Cell body

Largest part of a neuron that contains the nucleus, organelles, and Nissl bodies.

Dendrites

Threadlike extensions from the neuron cell body that carry nerve impulses toward the cell body.

Axon

Usually one long threadlike process that carries nerve impulses away from the cell body.

Unipolar neuron

Neuron with one process originating from the cell body; usually sensory neurons.

Bipolar neuron

Neuron with one dendrite and one axon; found in areas such as the eye and inner ear.

Multipolar neuron

Neuron with several dendrites and one axon; most common type in the brain and spinal cord.

Afferent (sensory) neurons

Neurons that carry nerve impulses toward the CNS (Arrives at CNS); started when receptors detect stimuli.

Efferent (motor) neurons

Neurons that carry nerve impulses away from the CNS (Exits CNS) to muscles or glands.

Astrocytes

CNS glial cells that help form the blood-brain barrier and support/protect neurons.

Microglia

CNS glial cells responsible for immune defense that remove microorganisms and cellular debris.

Ependymal cells

CNS glial cells that line fluid-filled spaces and help circulate fluid with cilia.

Oligodendrocytes

CNS glial cells that form myelin sheaths around axons in the CNS.

Schwann cells

PNS glial cells that form myelin sheath and neurilemma around axons in the PNS and support neuron cell bodies.

Resting membrane potential

Polarized resting state where the outside of the membrane is more positive than the inside, maintained by the $\text{Na}^+/\text{K}^+$ pump moving $3\text{Na}^+$ out and $2\text{K}^+$ in.

Depolarization

Phase of an action potential triggered when threshold is reached, opening $\text{Na}^+$ voltage-gated channels so large amounts of $\text{Na}^+$ enter the neuron, making the inside more positive.

Repolarization

Phase of an action potential where $\text{Na}^+$ voltage-gated channels close and $\text{K}^+$ voltage-gated channels open, allowing $\text{K}^+$ to move out of the neuron and making the inside negative again.

Absolute refractory period

Period during which another action potential cannot occur.

Relative refractory period

Period during which another action potential can occur, but requires a stronger stimulus.

Cerebrum

Largest part of the brain; responsible for conscious thought, sensory interpretation, memory, language, and voluntary movement.

Diencephalon

Brain division containing the thalamus, hypothalamus, and pineal body; relays sensory information, regulates homeostasis, and connects nervous and endocrine systems.

Cerebellum

Brain region that coordinates smooth, precise movements, balance, and posture.

Brainstem

Structure connecting the brain to the spinal cord; contains pathways for sensory/motor information and controls important reflexes and vital functions.

Frontal lobe

Cerebral lobe controlling voluntary movement; contains Broca's area for motor speech.

Parietal lobe

Cerebral lobe that processes somatic sensory information (touch/sensation) from skin and skeletal muscles.

Temporal lobe

Cerebral lobe responsible for hearing and smell; contains Wernicke's area for understanding language.

Occipital lobe

Cerebral lobe responsible for vision.

Insula

Cerebral lobe responsible for taste interpretation and memory.

Medulla oblongata

Part of the brainstem containing vital reflex centers that control heart rate, blood pressure, breathing, swallowing, and vomiting.

Pons

Brainstem structure that acts as a bridge for information and helps regulate breathing and movement.

Midbrain

Brainstem structure that carries ascending and descending information and contains reflex centers for vision and hearing.

Reticular Formation

Network of gray and white matter in the brainstem involved in reflexes, alertness, and consciousness.

Thalamus

Major relay station for sensory information going to the cerebral cortex; helps with awareness, emotions, alertness, and some reflexes.

Hypothalamus

Diencephalon structure that regulates body temperature, water balance, metabolism, thirst, appetite, pain, and pleasure; controls the pituitary gland.

Pineal Body

Structure in the diencephalon that produces melatonin and helps regulate the body's biological clock/sleep patterns.

Broca's Area

Region in the frontal lobe that controls the motor aspects of speech.

Wernicke's Area

Region in the temporal lobe responsible for understanding language.

Non-vital reflex centers

Centers found throughout the medulla, pons, and midbrain controlling reflexes not essential for basic survival, such as vomiting, coughing, hiccups, swallowing, and sneezing.

Vital reflex centers

Centers located in the medulla oblongata necessary for survival, including respiratory centers, cardiac control centers, and the vasomotor center.

Gray matter

Nervous tissue in the center of the spinal cord (butterfly/H shape) containing mostly neuron cell bodies and unmyelinated fibers; involved in processing and reflexes.

White matter

Nervous tissue surrounding gray matter in the spinal cord consisting mostly of myelinated axons; carries nerve impulses from one area to another.

Nuclei

Regions or clusters of gray matter located within the Central Nervous System (CNS).

Ganglia

Collections or clusters of gray matter (neuron cell bodies) located within the Peripheral Nervous System (PNS).

Tracts

Bundles of myelinated axons (white matter) located within the Central Nervous System (CNS).

Nerves

Bundles of myelinated axons (white matter) located within the Peripheral Nervous System (PNS).

Dorsal root

Also called the posterior root; carries sensory/afferent information into the spinal cord and contains sensory neuron cell bodies in the dorsal root ganglion.

Ventral root

Also called the anterior root; carries motor/efferent information away from the spinal cord to muscles and glands.

Dura mater

Tough outer layer of the meninges that provides strong protection for the CNS.

Arachnoid mater

Spiderweb-like middle layer of the meninges; lies above the subarachnoid space which contains cerebrospinal fluid (CSF).

Pia mater

Thin, delicate inner layer of the meninges that closely covers the brain and spinal cord and surrounds blood vessels.

Cerebrospinal fluid (CSF)

Clear fluid produced by the choroid plexus inside the brain's ventricles that protects the CNS, provides nutrients, and maintains stable conditions.

Endoneurium

Connective tissue layer that wraps around each individual nerve fiber.

Perineurium

Connective tissue layer that wraps around a group of nerve fibers called a fascicle.

Epineurium

Connective tissue layer that wraps around the entire nerve.

Cranial Nerve I (Olfactory nerve)

Sensory cranial nerve responsible for smell.

Cranial Nerve II (Optic nerve)

Sensory cranial nerve responsible for vision.

Cranial Nerve III (Oculomotor nerve)

Motor cranial nerve controlling eye movement, pupil size, and lens accommodation.

Cranial Nerve IV (Trochlear nerve)

Motor cranial nerve controlling eye movement.

Cranial Nerve V (Trigeminal nerve)

Mixed cranial nerve responsible for facial sensation and chewing.

Cranial Nerve VI (Abducens nerve)

Motor cranial nerve controlling lateral eye movement.

Cranial Nerve VII (Facial nerve)

Mixed cranial nerve responsible for taste and facial expressions.

Cranial Nerve VIII (Vestibulocochlear nerve)

Sensory cranial nerve responsible for hearing and equilibrium/balance.

Cranial Nerve IX (Glossopharyngeal nerve)

Mixed cranial nerve responsible for taste, tongue sensation, swallowing, and saliva.

Cranial Nerve X (Vagus nerve)

Mixed cranial nerve responsible for sensation and control of many organs; affects heart rate and digestion.

Cranial Nerve XI (Accessory nerve)

Motor cranial nerve controlling head and shoulder movement.

Cranial Nerve XII (Hypoglossal nerve)

Motor cranial nerve controlling tongue movement.

Chemoreceptors

Sensory receptors that detect chemicals, such as smell and taste.

Nociceptors

Sensory receptors that detect pain and tissue damage.

Mechanoreceptors

Sensory receptors that detect pressure, vibration, sound, and body position.

Thermoreceptors

Sensory receptors that detect temperature changes.

Osmoreceptors

Sensory receptors that detect changes in solute concentration.

Olfaction

Sense of smell; receptors in nasal epithelium detect dissolved chemicals and transmit signals via cranial nerve I.

Gustation

Sense of taste; taste receptors in taste buds detect five tastes (sweet, sour, salty, bitter, umami) and transmit signals via cranial nerves VII, IX, and X.

Auricle (pinna)

External ear structure that collects sound.

Auditory canal

External ear canal that carries sound toward the eardrum.

Tympanic membrane

Structure of the external ear (eardrum) that vibrates when hit by sound waves.

Ossicles

The three small bones of the middle ear (malleus, incus, stapes) that transfer and amplify sound.

Eustachian tube

Middle ear structure that helps equalize pressure on both sides of the eardrum.

Cochlea

Inner ear structure responsible for hearing.

Vestibule

Inner ear structure responsible for stationary equilibrium and head position.

Semicircular canals

Inner ear structures responsible for dynamic equilibrium and head rotation.

Organ of Corti

Structure within the cochlea containing hair cells that are stimulated by fluid movement to create nerve impulses for hearing.

Fibrous tunic

Outer layer of the eye consisting of the sclera and cornea.

Vascular tunic

Middle layer of the eye consisting of the choroid, ciliary body, and iris.

Nervous tunic

Inner layer of the eye consisting of the retina, rods, and cones.

Accommodation

The eye's process of altering lens shape and pupil size to focus images on the retina.

Dorsal column

Major ascending sensory tract carrying information regarding fine touch and proprioception/body position.

Spinothalamic tract

Major ascending sensory tract carrying information regarding pain and temperature.

Reflex arc

Pathway of a reflex consisting of a receptor, an afferent neuron, a control center/interneuron, an efferent neuron, and an effector.