Chapter 5 System 5 Nervous System Flashcards
Nerve fibers
Projections from the body of the nerve cell that carry nervous impulses
Dendrites
Connect with other neurons to receive information
Axon
Conducts impulses away from the cell body
Synapse
The junction where nerve signals jump from one nerve to another
Neurotransmitter
Is a chemical that sends a nerve signal across a synapse
Sensory neuron
Carries impulses from sense organs to the brain
Motor neuron
Carries nerve impulses from the brain to the effectors
Interneuron
Carries impulses from one neuron to another
Myelin sheath
Covers the axons of most nerves.
Made of fatty Schwann cells.
Insulates the nerve and aids in the conduction of the nerve impulse.
Neurons have the ability to react to certain stimuli (____) and to transmit an impulse generated by that stimulus over a distance or to another neuron (____).
Irritability
Conduct ability
Functionally, what are the three types of neurons?
Sensory / afferent neurons
Motor / efferent neurons
Interneurons / internuncial neurons
Sensory / afferent neurons
Sensations of touch, cold, heat, sight, hearing, taste, or pain are carried as impulses to the brain
Motor / efferent neuron
Carry nerve impulses from the brain to the effectors (the muscles or glands they control).
Interneurons / internuncial neurons
Located in the brain and spinal cord.
Carries impulses from one neuron to another.
Transmit and direct impulses from one place in the spinal cord or brain to another
Nerves
Are bundles of fibers held together by connective tissue that originate in the brain and spinal cord and distribute branches all over the body
Afferent nerves
Carry impulses toward the spinal cord or brain
Central nervous system
Consists of the brain and spinal cord
Meninges
A special connective tissue membrane that covers the CNS incased by bone
Meningitis
Is an acute inflammation of the pia mater and arachnoid mater around the brain and spinal cord
The three layers to meninges
Dura mater -outer -tough mother
Arachnoid mater -middle -spider layer
Pia mater - innermost -delicate mother
The primary function of the nervous system is to…
Collect a multitude of sensory information;
Process, interpret, and integrate that information;
Initiate appropriate responses throughout the body
The nervous system is composed of…
the brain, spinal cord, and peripheral nerves
Cerebrospinal fluid
Flows through and around the brain and spinal cord to nourish and protect them.
Main function is to protect the CNS by acting as a shock absorber for the delicate tissue
A clear fluid derived from the blood and secreted into the inner cavities or ventricles of the brain
The brain
The principal nerve center
Body’s largest and most complex nerve tissue
Containing in excess of 10 billion neurons and innumerable nerve fibers
Located in and protected by the cranium
Controls sensations, muscles, glandular activity, power to think and feel emotion
The brain includes… (4)
- Cerebrum
- Cerebellum
- Diencephalon
- Brain stem
Cerebrum
Largest portion, making up the front and top of the brain
Mental activity; speech, sensations, communication, memory, reasoning, will, emotions
Divided by a central fissure into left and right cerebral hemispheres.
Which is connected by bundles of nerve fibers called the corpus callosum. Provides communication between left and right hemispheres
The functions of the nervous system (4)
- To rule the body by controlling all visible and invisible activities
- To control human thought and conduct
- To govern all internal and external movements of the body
- To give the power to see, hear, move, talk, feel, think, and remember
Neuron / nerve cell
Is the structural unit of the nervous system
Cerebellum
Smaller part of the brain
Located below the cerebrum and at the back of the cranium
Helps to maintain body balance, coordinates voluntary muscles, makes muscular movement smooth and graceful
Diencephalon
Includes the hypothalamus, thalamus, and pineal and pituitary glands
Located in the center of the brain
The pituitary gland is considered to be the master gland because it’s hormones control other endocrine glands
Pituitary gland
Considered to be the master gland because it’s hormones control other endocrine glands
Located at the base of the brain in the sella turcica of the sphenoid bone
Brain stem
Has three parts; midbrain, the pons, and the medulla oblongata
these contain intricate masses of nerve fibers that relay and transmit impulses from one portion of the brain to another
Midbrain; contains the main nerve pathways connecting the cerebrum with the lower nervous system
The pons; between midbrain and medulla oblongata. relays nerve impulses between cerebrum - medulla and cerebrum - cerebellum
Medulla; is an enlarged continuation of the spinal cord that extends from the foramen magnum to the pons and connects the brain to the spinal cord. Regulates movement of the heart and controls vasoconstriction of the arteries, also the depth and rate of respiration
Spinal cord
Extends downward from the brain and is housed in and protected by the vertebral column
Consists of 31 segments
Peripheral nervous system
Consists of all the nerves that connect the CNS to the rest of the body
Autonomic nervous system
Regulates the action of glands, smooth muscles, and the heart
Somatic nervous system
Consists of the nerves that connect the CNS to the voluntary muscles and skin
Cranial nerves
12 pairs of nerves that emerge from the brain through openings in the base of the cranium
Cervical plexus
Consists of the four upper cervical nerves that supply the skin and control the movement of the head, neck, and shoulders
Brachial plexus
Is composed of four lower cervical nerves and the first pair of thoracic nerves that control arm movements
Lumbar plexus
Is formed from the first four lumbar nerves
Sacral plexus
Is formed from the fourth and fifth lumbar nerves, and the first four sacral nerves
Sciatic nerve
Is the largest and longest nerve in the body
Olfactory nerve
Sensory nerve
Nose
Sense of smell
- Only
- Old
- Ostriches
- Tip
- Toe
- Fresh
- Acres
- Giving
- Vast
- Amounts
- Hope
Olfactory Optic Oculomotor Trochlear Trigeminal or trifacial Abducent Facial Acoustic Glossipharyngeal Vagus Accessory "spinal" Hypoglossal
Optic nerve
Sensory nerve
Retina of eye
Sense of sight
Oculomotor nerve
Motor and sensory (proprioceptive) nerve
Muscles of eye
Controls eye movements
Trochlear nerve
Motor and sensory (proprioceptive) nerve
Superior oblique muscle of the eye
Rotates eyeball downward and outward
Trigeminal or trifacial nerve
Motor and sensory nerve
Face, teeth, and tongue
Controls sensations of the face and movements of the jaw and tongue
Abducent nerve
Motor and sensory (proprioceptive) nerve
Recti muscles of the eye
Rotates eyeball outward
Facial nerve
Motor and sensory nerve
face and neck
Controls facial muscles of expression and some muscles of the neck and ear
Acoustic or auditory nerve
Sensory nerve
Ear
Sense of hearing
Glossopharyngeal nerve
Motor and sensory nerve
Tongue and pharynx
Sense of taste
Vagus or pneumogastric nerve
Motor and sensory nerve
Pharynx, larynx, heart, lungs, and digestive organs
Controls sensations and muscular movements relating to talking, heart action, breathing, and digestion
Spinal Accessory nerve
Motor nerve
Shoulder
Controls movements of neck muscles
Hypoglossal nerve
Motor nerve
Tongue and neck
Controls movements of the tongue
dermatoma
is an area of the skin supplied by nerve fibers originating from a single spinal nerve root
sensory receptors can be characterized as…(5)
mechanoreceptors thermoreceptors photoreceptors chemoreceptors nociceptors
mechanoreceptors
respond to mechanical stimulation or tissue distortion such as touch, pressure, vibration, and stretch.
In the skin;
ruffini end organs,
pacini corpuscles,
merkel disks
Proprioceptors located in the muscles, fascia, and joints. (Spindle cells and Golgi tendon organs)
thermoreceptors
Located in the skin and and in the mouth.
Two types of thermoreceptors detect heat and cold
chemoreceptors
Located in the mouth and nose
Are sensitive to certain chemical stimuli and gives us the sense of smell and taste
photoreceptors
Two types of photoreceptors
Located in the retina of the eyes, rods, and cones are sensitive to light and detect color
They give us the ability to see color and form
nocireceptors
Detect pain and are located in nearly every tissue in the body except the brain
They respond to extreme stimuli and tissue damage
Serve as a protective function by informing us that when something is wrong, it hurts
autonomic nervous system
Regulates the action of glands, smooth muscles, and the heart
Circulation of blood, activity of digestion tract, respiration, and body temperature
Involuntary
Subdivided into…
Sympathetic system excited
Parasympathetic system inhibits
sympathetic nervous system
Supplies the glands, involuntary muscles of internal organs, and walls of blood vessels with nerves and prepares the body for energy expending circumstances
Energy expending, stressful, or emergency situations
Increased respiration, dilated pupils, and increased heart rate and cardiac output
parasympathetic nervous system
Functions to conserve energy and reverse the action of the sympathetic division
Calm, in a state of relaxation
Reduced heart rate, respiration, and blood pressure, and increased digestion and elimination
neurologic pathway
Is the route that a nerve impulse travels through the nervous system
reflex
Is the simplest form of nervous activity, which includes a sensory and motor nerve
reflex arc
Is the nerve pathway of a reflex
Withdrawal reflex / flexor reflex
Occurs when a person touches something sharp or hit and immediately pulls away, thereby preventing excessive injury
Automatic, unconscious, involuntary
exteroceptors
Record conscious sensations such as heat, cold, pain, and pressure throughout the body
the areas of the body that are particularly sensitive to reflex influences are…(5)
- The skin of the back between the shoulders
- The side of the chest between the fourth and sixth ribs
- The skin at the upper and inner portion of the though
- The skin overlying the gluteal muscles
- The sole of the foot
proprioceptors
Sense where the body is and how it moves
System of sensory and motor nerve activity that provides info to the CNS about the position and rate of movement of different body parts
Located in the muscle, tendons, joints, or fascia.
Three major categories of proprioceptors are;
Muscle spindle cells
Golgi tendon organs
Joint proprioceptors
muscle spindle cells
Sensory organs in muscle that detect the rate of stretch in muscles
Made up of a specialized contractile tissue called intrafusal muscle fibers
golgi tendon ograns
Are multibranched sensory nerve endings located in tendons
Measure the amount of tension produced in muscle cells as a result of the muscles stretching and contracting
Also monitor the amount of force pulling on the bone to which the tendon attaches
What are the two main types of joint proprioceptors?
Pacini’s corpuscles
Ruffini’s endings
These are mechanoreceptors located in the connective tissue or fascia surrounding the joints that sense the position and movements of the joints
Neurologic disorders
Disease of the nervous system.
Birth defects, trauma, or degenerative disease
Infection, blood clots, tumors, or hemorrhage
multiple sclerosis
Occurs in young adults and results from the breakdown of the myelin sheath
Is a degenerative nerve disease that affects the body’s ability to control the muscles
Symptoms include muscle weakness, spasticity, loss of coordination or balance, loss of bladder control
parkinson’s disease
Occurs as a result of the degeneration of certain nerve tissues that regulate body movements
Degeneration of an area of the cerebrum that produces the neurotransmitter dopamine
Massage is useful to maintain flexibility, relax muscles, and relieve anxiety and depression
amyotrophic lateral sclerosis
ALS
Aka Lou Gehrig’s disease
Progressive and eventually fatal neurological condition that causes the motor neurons of the brain and spinal cord to degenerate and die, causing weakness, spasticity, and atrophy of the voluntary muscles
Affects 2x as many men as women
Weakness or twitching of a leg, arm, or hand or slurred speech
3-5 years 50% death rate
10 years 90% death rate
Only attacks the motor neuron and does not affect the intelligence, memory, or personality, or the ability to taste, smell, and hear or the sense of touch
Massage can provide a great amount of comfort and relief
spinal cord injury
SCI
Is caused by trauma or disease to the vertebral column or to the spinal cord itself
Complete injury; when there is no motor or sensory function below the injury level
Incomplete; when not all the spinal nerve fibers are affected and there is still some function
quadriplegia or tetraplegia
Is paralysis of the arms and legs caused by a stroke or spinal cord injury
C-1 through T-1
paraplegia
Paralysis of the lower extremities; does not affect the arms or hands
T-2 through S-5
skin brushing
A light, brisk brushing using a dry vegetable bristle bath brush
Can help to reduce edema and improve the quality of the skin
cerebrovascular accident / stroke
Is caused by a blood clot or ruptured blood vessel in or around the brain that subsequently destroys nerve tissue
3rd leading cause of death in USA
hemiplegia
Is the condition of unilateral paralysis caused by a stroke
Contraindicated
epilepsy
Is a neurologic condition in which there is an abnormal electrical activity in the CNS without apparent tissue abnormalities
Indicated for someone with a history of seizure disorder
polio / poliomyelitis
Is a crippling or even deadly disease that affects the motor neurons of the medulla oblongata and spinal cord
Indicated with physician
encephalitis
Refers to several related viral diseases that cause an inflammation of the brain or the meninges
Carried by animals or birds, mosquito bite, or it can arise as a secondary infection from measles, mumps, or chickenpox
meningitis
Is an acute inflammation of the pia and arachnoid mater around the brain and spinal cord.
Is often a secondary infection from bacteria traveling from the middle ear, respiratory tract, lungs, or sinuses
Contraindicated during acute and active stages
shingles
Is an acute inflammation of a nerve trunk and the dendrites at the end of the sensory neurons by the herpes zoster virus
Contraindicated because of the risk of infection
neuritis
Inflammation of a nerve
Not a disease but a symptom of some other condition such as a herniated disk, herpes zoster, or diabetes mellitus.
Affects the nerves of the peripheral nervous system
thoracic outlet syndrome
TOS
Is caused by a compression or entrapment of the brachial nerve plexus and/or blood vessels going to or from the arm
Results in pain, paresthesia, numbness, and/or weakness in the shoulder, neck, and arm
Indicated if caused by muscle
carpal tunnel syndrome
Is the result of compression of the median nerve as it passes through the anatomical tunnel of the wrist, causing pain and weakness in the thumb and/or first three fingers
Repetitive stress injury
Neuralgia
Pain associated with neuritis
Polyneuritis
Generalized neuritis affecting several nerves
Mononeuritis
Neuritis affects a specific nerve
Pinched nerve
Can refer to any of a wide variety of conditions in which pressure on a nerve is responsible for pain, numbness, or a reduction of function
Could be a result of nerve compression or nerve entrapment
Indicated to relieve the constriction of soft tissue
