The Nervous System Flashcards
Functions of the nervous system
To transmit info from one part of the body to another and coordinates and controls body functions
Divisions of the nervous system
Central nervous system and peripheral nervous system
Central N.S
the brain and spinal cord
Peripheral N.S
Nerves that extend to the parts of the body
Cells of the nervous systems
Neurons and glia
Types of neurons
Sensory, motor, and inter neurons
Sensory neurons
(Afferent) transmit impulses toward the spinal cord and brain
Motor neurons
(Efferent) transmit impulses toward the body
Inter neurons
Directly connect sensory and motor neurons in the spinal
The synapse
Tiny space between the axon of one neuron and the dendrites of another
Dendrites
Receive impulses (tree like)
Axon
Send impulses away (covered in myelin)
Myelin
Fatty substance covering Schwann cells (like the rubber on the wire)
Nodes of Ranvier
The stuff between the Schwann cells
Dopamine
Stuff that create neurotransmitters
Endorphin
Block the impulse
Neurotransmitters
Chemical “bridges”, flood the space (are released by pre-synaptic neuron)
Brain stem
Controls vital functions
- heartbeat
- breathing
- blood pressure
Brain stem has three parts
Medulla oblongata
Pons
Midbrain
Diencephalon
Interior center of the brain
Hypothalamus
Controls: -body temp
- sleep cycle
- appetite
- sexual arousal
Thalamus
- Relays sensory impulses to the appropriate part of the brain
- associates sensations with emotions
Cerebellum
Controls coordination of movement, balance, and equilibrium
Cerebrum
Largest upper most part of the brain
- thinking part
- perception
- emotions
- memory
Spinal cord
About 17-18 inches long
Extends from occipital bone to L1
Provides two way communication
Two ways of communication what are they
Ascending tracts conduct impulses up the cord to brain
Descending tracts conduct impulses down the cord from brain
Meninges
Tough, fluid filled membrane cover ing brain and spine made of three layers
Layers of meninges
Dura-tough outer layer (next to bone)
Arachnoid-fluid fills spaces (cobweb)
Pia-directly touching brain
Cerebrospinal fluid
Bathes the brain and spinal cord
Acts as a shock absorber
Continually produced
Spinal nerves
31 pairs
Have sensory and motor functions
Cranial nerves
12 pairs
Autonomic nervous system
Motor neurons that conduct impulses to the heart, smooth, muscles and glands of the body
2 branches of autonomic nervous system
Parasympathetic- controls involuntary muscles during normal every day conditions
Sympathetic- controls involuntary muscles during stressful or emergency conditions
