Chapter 5E - Nervous System Flashcards
Divide the nervous system by structures
- Central nervous system
– brain (and brainstem)
– spinal cord - Peripheral nervous system
– motor
– sensory
– autonomic
State the general functions of the nervous system
– Receives and interprets stimuli and information from the environment
– generate responses to stimuli and information
– stores information for future use (memory and learning)
Divide the nervous system by function
- Voluntary
- skeletal muscles (somatic) - Involuntary
– autonomic
– smooth and cardiac muscles
Divide the nervous system by direction of travel of impulses
- Afferent nerves
– conduct impulses toward the brain (like sensory nerves) - Efferent nerves
– conduct impulses away from the brain (like a motor and Autonomic)
Describe the structures of the neuron and the component parts and functions (6)
– Dendrites receive impulses from other nerves
– nerve body
– Axon is the long “arm” that carries the impulses to something (using electrolytes-depolarization)
– nerve “foot” is at the end of the axon – contains chemical mediators (neurotransmitters, works like a “key”) stored in vesicles
– synapse (or gap, cleft or junction) = the gap the chemical mediator has to cross to carry on the impulse
– receptor site (on the next surface, another nerve’s dendrites, or a muscle’s motor end plate, etc.) - receptor site works as “lock”
Describe the relatively unique characteristics of nerve tissue
- very sensitive to changes, especially to O2, glucose, and pH
- have very high metabolic rate generally, and the brain especially
– nerves cannot store oxygen or glucose (need a constant supply)
– nerves show effect of no oxygen or glucose in approximately 10 seconds
– brain cells do not require insulin to get glucose from the blood
– nerve cells do not regenerate if the die
Hemiparesis
One-sided muscular weakness
Indicates CVA or head injury
Hemiplegia
One-sided paralysis
Sign of CVA or head injury
Paraplegia
Paralysis of lower extremities
Indicates spinal injury
Quadriplegia
Paralysis of all four extremities
Indicates spinal injury
Priapism
Sustained erection in the male that indicates a spinal cord injury
Describe the autonomic nervous system and its significant parts
Sympathetic Nervous System
Common name: “fight or flight” system
Origin of nerves: thoracolumbar system
Chemical mediator: norepinephrine
Parasympathetic Nervous System
Common name: “feed and breed” system
Origin of nerves: craniocaudal system
Chemical Mediator: acetylecholine
Cranial Nerve III
Oculomotor Nerve
When stimulated, it causes the pupil to constrict - part of the parasympathetic nervous system
Cranial Nerve X
Vagus Nerve
When stimulated, causes the heart to slow down, digestion speeds up, and many other functions - it is the primary nerve of the parasympathetic nervous system
Meningitis
An inflammation of the meninges, the membranes that surround the brain and spinal cord
Can be caused by a bacteria or virus
Describe the impulse transmission along a nerve
- an “action potential” travels down the nerve axon making it permeable (the nerve is “polarized”)
- sodium floods in through the cell membrane ion gates (then it depolarizes)
- potassium is pushed out
- a neurotransmitter is released from the vesicles
- if oxygen and glucose are present, the nerve cell will make ATPs which will be used by the cell to run the sodium-potassium pump, pumping the sodium back out and the potassium back in ( then it repolarizes)
Describe neurotransmitters and their characteristics
Chemical mediators that are released by vesicles and a nerve foot with cross a synapse to stimulate a receptor site - the effect is always the same for the neurotransmitter in that receptor site, either stimulating a response, or inhibiting one
Cholinergic
Works like acetylcholine
motor nervous system, person pathetic nervous system, etc.
Adrenergic
Works like a adrenaline (epinephrine)
The catecholamines – endogenous sympathomimetics norepinephrine, epinephrine, dopamine
Serotonin
Present in platelets, mast cells, the brain, etc.
In euro transmitter in the central nervous system, and a potent vasoconstrictor
Describe the nervous system reflexive responses from chemoreceptors
Chemoreceptors – receptor sites that to take changes in their environment and signal to bring to create a change or adjustment (often homeostatic)
– central = located in brainstem (mostly response to changes in pH) [causes medulla oblongata to change the rate and depth of breathing]
– Peripheral = present in the carotid artery (carotid sinus) mostly response to changes in oxygen levels [there are others that detect osmolality, smell, ect.]
