Nervous System and Mental Health

Central Nervous System (CNS)

includes the brain and spinal cord. The functions of the central nervous system are to receive and process information and to regulate all bodily activity.

Peripheral Nervous System (PNS)

includes the 12 pairs of cranial nerves extending from the brain and the 31 pairs of peripheral spinal nerves extending outward from the spinal cord

Nerve

one or more bundles of neurons that connect the brain and spinal cord with other parts of the body

Tract

a bundle or group of nerve fibers located within the brain or spinal cord.

Ascending Nerve tracts

carry nerve impulses toward the brain

Descending Nerve Tracts

carry nerve impulses away from the brain.

Ganglion

a nerve center made up of a cluster of nerve cell bodies outside the central nervous system

Innervation

means the supply of nerves to a specific body part.

Plexus

a network of intersecting spinal nerves

Receptors

are sites in the sensory organs (eyes, ears, skin, nose, and taste buds) that receive external stimulation

Stimulus

is anything that excites (activates) a nerve and causes an impulse

Impulse

is a wave of excitation transmitted through nerve fibers and neurons

Reflex

is an automatic, involuntary response to some change, either inside or outside the body

Neurons

he basic cells of the nervous system that allow different parts of the body to communicate with each other.

Brain Waves

In the brain, this process creates patterns of neuron electrical activity

Dendrites

the root-like processes that receive impulses and conduct them to the cell body

Process

is a structure that extends out from the cell body

Axon

a process that conducts impulses away from the nerve cell

Terminal end fibers

the branching fibers at the end of the axon that lead the nerve impulse from the axon to the synapse

Synapse

the space between two neurons or between a neuron and a receptor organ

Neurotransmitters

are chemical substances that make it possible for messages to cross from the synapse of a neuron to the target receptor

Acetylcholine

released at some synapses in the spinal cord and at neuromuscular junctions; it influences muscle action

Dopamine

released within the brain and plays a role in motivation, pleasure, and muscle movement

Endorphins

naturally occurring substances that are produced by the brain to help relieve pain

Norepinephrine

affects alertness and arousal, increasing blood pressure and heart rate, and releasing stores of glucose in response to stress

Serotonin

which is released in the brain, has roles in sleep, hunger, and pleasure recognition

Glial Cells

provide support and protection for neurons, and their four main functions are

(1) to surround neurons and hold them in place,

(2) to supply nutrients and oxygen to neurons,

(3) to insulate one neuron from another, and

(4) to destroy and remove dead neurons.

Myelin Sheath

the protective covering made up of glial cells. This white sheath forms the white matter of the brain and covers some parts of the spinal cord and the axon of most peripheral nerves

White Matter

The portion of the nerve fibers that are myelinated

Myelinated

having a myelin sheath. It is the color of this covering that makes these fibers white.

Gray Matter

The portions of the nerve fibers that are unmyelinated

Unmyelinated

lacking a myelin sheath

Central Nervous system

made up of the brain and spinal cord. These structures are protected externally by the bones of the cranium and the vertebrae of the spinal column

Meninges

the system of membranes that enclose the brain and spinal cord

Dura Matter

the thick, tough, outermost membrane of the meninges.

Dura

hard

Matter

mother

Epidural space

The inner surface of the vertebral column, which is located between the walls of the vertebral column and the dura mater of the meninges, contains fat and supportive connective tissues to cushion the dura mater.

Subdural space

both the skull and vertebral column, located between the dura mater and the arachnoid membrane

Arachnoid membrane

resembles a spider web, is the second layer of the meninges and is located between the dura mater and the pia mater

Arachnoid

having to do with spiders.

Subarachnoid Space

located below the arachnoid membrane and above the pia mater, contains cerebrospinal fluid

Pia Mater

the third layer of the meninges, is located nearest to the brain and spinal cord. It consists of delicate connective tissue that contains a rich supply of blood vessels

pia

tender or delicate

Cerebrospinal fluid/ spinal fluid

is produced by special capillaries within the four ventricles located in the middle region of the cerebrum

Cerebrum

which is the largest and uppermost part of the brain, consists of four lobes.

Controls the highest level of thought, including judgment, memory, association, and critical thinking. It also processes sensations and controls all voluntary muscle activity.

Thalamus

located below the cerebrum.

Relays sensory stimuli from the spinal cord and midbrain to the cerebral cortex. The thalamus suppresses some stimuli and magnifies others.

Hypothalamus

located below the thalamus.

Controls vital bodily functions (Table 10.3).

Cerebellum

located in the lower back of the cranium below the cerebrum.

Coordinates muscular activity and balance for smooth and steady movements.

Brainstem

located in the base of the brain and forms the connection between the brain and spinal cord.

Controls the functions necessary for survival (breathing, digestion, heart rate, and blood pressure) and for arousal (being awake and alert).

Cerebral

pertaining to the cerebrum or to the brain

cerebr

brain

Cerebral cortex

made up of gray matter, is the outer layer of the cerebrum and is made up of elevated folds and deep fissures

Gyri

the elevated folds of gray matter in the cerebral cortex

Sulci

the fissures of the cerebral cortex (singular, sulcus). As used here

Cerebral hemispheres

the cerebrum is divided to create two of these

Corpus Callosum

the lower midpoint where

Left cerebral hemisphere

controls the majority of functions on the right side of the body

Right cerebral hemisphere

controls most of the functions on the left side of the body.

Cerebral lobes

Each cerebral hemisphere is subdivided to create pairs

Frontal Lobe

controls skilled motor functions, memory, and behavior.

Parietal Lobe

receives and interprets nerve impulses from sensory receptors in the tongue, skin, and muscles

Occipital lobe

controls eyesight.

Temporal lobe

controls the senses of hearing and smell, and the ability to create, store, and access new information.

Thalamus

which is located below the cerebrum, produces sensations by relaying impulses to and from the cerebrum and the sense organs of the body.

Hypothalamus

is located below the thalamus

Cerebellum

the second-largest part of the brain. It is located at the back of the head below the posterior portion of the cerebrum

Brainstem

the stalk-like portion of the brain that connects the cerebral hemispheres with the spinal cord

Midbrain and Pons

provide conduction pathways to and from the higher and lower centers in the brain

Medulla Oblongata

is located at the lowest part of the brainstem, is connected to the spinal cord. It controls basic survival functions, including the muscles that make possible respiration, heart rate, and blood pressure, as well as reflexes

Spinal Cord

long, fragile, tube-like structure that begins at the end of the brainstem and continues down almost to the bottom of the spinal column

Peripheral Nervous System

consists of the 12 pairs of cranial nerves that extend from the brain, plus 31 pairs of spinal nerves that extend from the spinal cord

Peripheral

pertaining to body parts that are away from the center of the body.

Autonomic nerve fibers

carry instructions to the organs and glands from the autonomic nervous system

Sensory nerve fibers

receive external stimuli, such as how something feels, and transmit this information to the brain where it is interpreted.

Somatic nerve fibers/ motor nerve fibers

convey information that controls the body’s voluntary muscular movements

Cranial nerves

originate from the under-surface of the brain. The two nerves of a pair are identical in function and structure, and each nerve of a pair serves half of the body

Peripheral spinal nerves

are grouped together and named based on the region of the body they innervate.

Autonomic nervous system

organized into two divisions, one comprising sympathetic nerves and the other parasympathetic nerves. The autonomic nervous system controls the involuntary actions of the body such as the functioning of internal organs

Homeostasis

maintaining constant internal environment of the body

Sympathetic nerves

prepare the body for emergencies and stress by increasing the respiratory rate, heart rate, and blood flow to muscles

Flight-or-flight response

which is the body’s natural reaction to real or imaginary danger.

Parasympathetic nerves

return the body to normal after a response to stress. They also maintain normal body functions during ordinary circumstances that are not emotionally or physically stressful.

Anesthesiologist

a physician who specializes in administering anesthetic agents before and during surgery

esthesi

feeling

Anesthetist

a medical professional who specializes in administering anesthesia but is not a physician, for example, a nurse anesthetist

esthet

feeling

psychiatrist

physician who specializes in diagnosing and treating chemical dependencies, emotional problems, and mental illness

Psychologist

has a doctoral degree but is not a medical doctor and evaluates emotional problems

Social worker

is a trained therapist, usually with a master’s degree

Cephalalgia/ headache

pain in the head

Migraine headache

which may be preceded by a warning aura, is characterized by throbbing pain on one side of the head.

Warning aura

a visual disturbance perceived by the patient preceding a migraine headache or epileptic seizure

Cluster headaches

intensely painful headaches that affect one side of the head and may be associated with tearing of the eyes and nasal congestion

Encephalocele/ craniocele

a congenital herniation of brain tissue through a gap in the skull

Encephal/o

brain

-cele

hernia

Congenital

present at birth

Herniation

protrusion of a structure from its normal position

Meningocele

the congenital herniation of the meninges through a defect in the skull or spinal column