Nervous system Flashcards
what is the nervous system function
the nervous system controls, directs and coordinates body functions.
The main function of the nervous system is communication including:
a. Coordinating and controlling all the body’s activities
b. Serving as a memory bank for future reference
c. Interpreting messages from the five senses.
what are the two main divisions of the nervous system
-there is the central nervous system which consists of the brain and the spinal cord
-the peripheral nervous system involves the nerves throughout the body. —– the automonic nervous system controls involuntary body functions
what are the structures of the nervous system
brain - A large soft mass of nerve tissue divided into 2 halves, contained within the
skull
spinal cord - The spinal cord is really an extension of the brain. It is made up of nerve
tissue and extends down to just above the small of the back.
nerves - Nerves are made up of nerve cells which are specialized to conduct electric impulses. Many nerve cells are found in boundless and are held
together by connective tissue. These bundles resemble telephone cables.
Nerve tissues are very delicate and so are carefully protected by fluid,
membranes and bone
what are the two types of nerves
Sensory Nerves: go from organs to brain
Motor Nerves: go from brain and spinal cord to the muscles
what is myelin sheath
A covering on some nerve
fibers which:
Protects
Insulates
Speeds up impulses
what two cells is nerve tissues made up of
Neuroglia cells
nourish, protect, insulate neurons
Neurons
the nerve cells that transmit information
what are the three parts of a neuron
Dendrites
Have receptors that receive impulses from other
cells (e.g. heat, pain, cold)
Cell body
receives impulses from dendrites
contains nucleus
Axon
Carries info from cell body to axon
travels to axon terminals where
neurotransmitters are stored
What are neurotransmitters?
transmitters cross synapse to next dendrite
What is a synapse?
what are the 3 main parts of the brain
- Cerebrum
- Cerebellum
- Brain stem
what is the cerebrum
Largest part of brain
Center of “thought and intelligence”
Left & right hemispheres control
opposite sides of the body
what is the cerebellum
Coordinates body movements
balance, muscle tone, coordination of
motor movements, learning complex
motor skills through repetition
what is the brain stem
connects cerebrum to
spinal cord
Pons
relays info between medulla and
cerebrum
Medulla (or medulla oblongata)
Lowest part of the brain stem
Controls many automatic activities:
heart rate, breathing, blood
vessel size (contract/dilate),
what are the meninges
layers covering brain
and spinal cord:
Dura mater – outer layer next to
skull
Arachnoid – middle layer
Pia mater – inner layer containing
blood vessels
what are the two parts of the autonomic nervous system
- Sympathetic
in general, speeds up
body functions
“fight or flight” - Parasympathetic
Responsible for our
“normal” condition
after “fight or flight”
events
changes to the nervous system with aging
- Nerve cells shrink; blood flow to
brain reduced
May cause shorter or different memory
Slower responses
Dizziness - Change in sleep patterns
- Decreased sensitivity to pressure,
heat, cold, touch - Decreased sensitivity to pain, but an
older person with greater chronic
health problems may have more pain
overall
what is paralysis
Defined as: loss of movement – severity varies
Types: Paraplegia (waist down), Quadriplegia (neck down-
arms, legs, upper body and breathing (respiratory) muscles may
be affected; Hemiplegia (one side (left or right) and can be
seen with strokes)
Caused by:
- Spinal cord injuries
- Stroke
- Other causes…
