Nervous System Deck Flashcards
nervous system
the communication network for the body; the most highly organized system
the main function of the nervous system
to coordinate all of the body’s activities
when changes occur inside or outside the body
the nervous system allows it to recognize them and respond as needed
the basic element of the nervous system
the neuron
neuron/nerve cell
job is to transmit a message from one cell to the next
in order for a neuron to perform its job
contains special fibers that extend from the cytoplasm of the cell body
dendrites
conduct impulses toward the cell
a nerve cell
may have several dendrites
axons
conduct impulses away from the cell
each nerve cell
has only one axon
many axons
covered by a fatty tissue called the myelin sheath
myelin sheath
protects the axons and speeds up the impulse as it travels
impulse
refers to a force that produces sudden activity in nerve cells and is transmitted in a wave along nerve fibers
the axon of one neuron
lies close to many dendrites of other neurons
synapse
the space between a dendrite and an axon
neurotransmitters
special chemicals that help impulses “jump” the synapse to pass the message from cell to cell
neurons
form bundles called nerves
the impulses
can follow many different routes throughout the body
types of neurons
afferent, efferent, associative
afferent neurons/sensory neurons
carry messages from all parts of the body to the brain and spinal cord
efferent neurons/motor neurons
carry messages from the brain and spinal cord to the muscles and glands
associative neurons/interneurons
carry messages from afferent neurons to efferent neurons
the two main divisions of the nervous system
central nervous system and peripheral nervous system
central nervous system
consists of the brain, spinal cord, optic (eye) nerves
peripheral nervous system
consists of nerves that reach all parts of the body
autonomic nervous system
the special division of the peripheral nervous system which controls the involuntary activities of the vital organs
spinal cord
controls many reflex actions; acts as a pathway for messages to and from the brain and the nerves that go to the muscles and glands
involuntary
refers to actions that are not controlled by a person’s conscious thought/will
brain
interprets, organizes, and stores information
job of the brain
to control and direct body functions
the main sections of the brain
the cerebrum, diencephalon, cerebellum, brain stem
cerebrum
the largest and highest section of the brain; separated into four lobes; concerned with reasoning, the senses, speech, voluntary body movement
the four lobes of the cerebrum
frontal, parietal, temporal, occipital
diencephalon
includes two parts: the thalamus and the hypothalamus
thalamus
directs sensory impulses to the cerebrum
hypothalamus
controls the autonomic nervous system, body temperature, appetite, water balance, sleep, blood vessel constriction and dilation
the hypothalamus is a role-player in
emotions (ex.: anger, fear, pleasure, pain, affection)
cerebellum
responsible for coordination of muscle movements, balance and posture, muscle tone
brain stem
includes three parts
parts of the brain stem
the midbrain, the pons, the medulla oblongata
midbrain
conducts impulses between the brain parts and for certain eye and auditory reflexes
pons
directs messages to other parts of the brain and for chewing, saliva production; helps with respiration
medulla oblongata
connects with the spinal cord; regulates heartbeat, respiration, swallowing, blood pressure
spinal cord location
starts at the base of the brain stem and extends to the area around the first lumbar vertebrae in the lower back
encasement of the spinal cord
the vertebral column
spinal column/vertebral column
consists of 26 bones called vertebrae
spinal cord
controls many reflex actions; acts as a pathway for messages to and from the brain and the nerves that go to the muscles and glands
optic nerve location
in the back of the eye
optic nerve
responsible for transferring visual information from the retina to the vision centers of the brain via electrical impulses
the second of several pairs of cranial nerves
the optic nerve
the make-up of the optic nerve
made up of nerve cells; consists of over one million nerve fibers
the protector of the brain
the skull
the protectors of the spinal cord
the surrounding vertebrae
meninges
three layers of tough membranes that cover and protect the brain and spinal cord
the three meninges layers
- the dura mater - the outer layer
- arachnoid membrane - the middle layer
- pia mater - the innermost layer
cerebrospinal fluid
watery liquid that fills the brain’s four ventricles (hollow spaces); acts as a shock absorber
functions of the cerebrospinal fluid
- carries nutrients to some parts of the central nervous system
- helps remove metabolic products and wastes
movement of cerebrospinal fluid
flows throughout the brain and around the spinal cord for further protection
make-up of the peripheral nervous system
includes 12 pairs of cranial nerves and their branches and 31 pairs of spinal nerves and their branches
some of the cranial nerves
process input from special senses, such as sight, hearing, taste, smell
other cranial nerves
receive general sensations (ex.: touch, pressure, pain, temperature); send out impulses to control muscles
spinal nerves
carry messages to and from the spinal cord
each spinal nerve
goes directly to a certain part of the body or forms a network with other spinal nerves to reach a larger segment of the body
two divisions of the autonomic nervous system
the sympathetic and parasympathetic systems
the sympathetic and parasympathetic systems
usually work together to maintain a balanced state for the body
sympathetic system
in times of emergency, prepares the body for action with the “fight or flight” response
functions of the sympathetic system
- increases heart rate, respiration, blood pressure
2. slows the rate of digestion
parasympathetic system
after the stress is over (after the emergency), reverses the actions of the sympathetic system to counteract the effects and return the body to normal working conditions
autism/autism spectrum disorder
refers to a broad range of conditions characterized by challenges with social skills, repetitive behaviors, speech, nonverbal communication; a brain disorder
cause of autism
unknown
the nature of autism
appears to be a combination of genetic and environmental factors
the most common cause of dementia
Alzheimer’s disease
dementia
a general term for memory loss serious enough to interfere with daily life
Alzheimer’s disease
occurs when nerve cells in the brain die; a progressive neurodegenerative disease
results of Alzheimer’s disease
often results in impaired memory, thinking, behavior
in advanced stages of Alzheimer’s disease
complications from severe loss of brain function and can result in death
treatment for Alzheimer’s disease
no treatment that cures the disease or alters the disease’s process in the brain
myasthenia gravis
disease where the proper nerve pulses are not sent to the muscles
the result of myasthenia gravis
progressive muscle weakness and paralysis occur
cause of myasthenia gravis
exact cause unknown; thought that it may be related to an autoimmune process
cure for myasthenia gravis
none
treatment for myasthenia gravis
involves medication and lifestyle changes to cope with the disease
definitions/synonyms of cerebrovascular accident
- CVA
- stroke
- “brain attack”
cerebrovascular accident
occurs when there is a loss of blood flow, and in turn oxygen, to the brain
possible causes of cerebrovascular accident
a blood vessel bursting or being blocked by a blood clot
symptoms of cerebrovascular accident
vary depending on the area and the amount of brain tissue damaged
common symptoms of cerebrovascular accident
include weakness or paralysis on one side of the body, difficulty swallowing, visual or speech impairment, mental confusion, loss of consciousness
stroke
a leading cause of death in the United States
controlling risk factors of stroke
smoking, heart disease, diabetes (helps to prevent them)
treatment within the first three hours of a stroke
(ex.: using drugs to break up a clot and restore blood flow) can help to prevent brain damage
treatment for any damage
(from a stroke) involves therapy to help people recover from or adapt to the losses of mental or physical function
multiple sclerosis (MS)
disease of the central nervous system
the result of multiple sclerosis
progressive loss of muscle control
the myelin sheath in multiple sclerosis
slowly destroyed
the exact cause of multiple sclerosis
unknown; thought that it may be related to a virus or an autoimmune process
early symptoms of multiple sclerosis
include double vision, tingling and numbness, weakness, fatigue
as multiple sclerosis worsens
symptoms include tremors, speech impairment, paralysis
cure for multiple sclerosis
none
treatment for multiple sclerosis
involves medication and physical therapy to help control the symptoms and maintain functional ability as long as possible
