Nervous System Flashcards
(28 cards)
What is the nervous system fundamentally?
control system
What are the three functions of the nervous system and what do they mean?
Sensation: constant monitoring of internal and external environment by receptors that respond to appropriate stimuli. Ex: heat, light
Integration: interpretation and processing of sensory info and resulting decision to act or not. ex: move to talk to someone or not
action: activation or inhibition of effectors (muscles or glands) ex: actually moving
What is the CNS?
Central Nervous System
-brain and spinal cord
-where integration occurs (cognition) (made aware and decisions are made)
What is PNS?
Peripheral nervous system
- 12 cranial nerves and 31 spinal nerves (have both motor and sensory axons) that transmit electrical impulses (axn potentials) from:
receptors —-> CNS AND CNS —> effectors
What is the common split for dividing PNS?
- sensory: nerve cells (sensory neurons) transmit electrical impulses (axn potentials) from receptors–> CNS = afferent APs (periphery —> CNS)
-performs sensation function - motor: motor neurons transmit APs from CNS —> effectors = efferent APs.
-performs action function
What is the typical division of the PNS?
Somatic: involving parts we have conscious control of (skeletal muscle = somatic motor system) AND conscious sensation from (receptors in skin for touch, temp, pain = somatic sensory system)
autonomic (visceral) nervous system: involved with parts we DO NOT have conscious control of (smooth & cardiac muscle, glands = visceral motor) or receive conscious sensation from (cardiovascular & digestive = visceral sensory)
How is the autonomic (visceral) nervous system divided?
Sympathetic nervous system: “fight or flight” —redirects blood flow skeletal muscles and away from digestive tract. T1-L2
parasympathetic nervous system: “rest and digest” – redirects flow to digestive tract and away from skeletal muscles (mostly head and neck–salivary glands controlled) (predominant)
enteric division: digestive system and heart –> when things need to move
what is reciprocal inhibition?
excitation of one side of autonomic NS causes inhibition of other side (ex: excite sympathetic and inhibit parasympathetic)
what are neurons?
cells of nervous system that send and receive electrical impulses (APs) that allow for rapid control of bodies organ system
What is the long process of a neuron that transmits AP?
axon
What are the multiple short processes in neurons that allow the neuron to receive AP from other neurons?
dendrites
What are the two types of neurons found in the PNS? Identity which is what from images.
Motor: carry APs from CNS–> effector. Cell body in CNS but axon leaves and becomes PNS. With sufficient input produce AP that moves along axon and excites effector. Perform action aspect.
Sensory: carry APs from receptors–> CNS. Single long process that is specialized into a receptor at one end where AP is initiated by a stimulus. Will travel along process (axon/dendrite) until it reaches synaptic endings (in CNS). These sensory neurons perform sensation function of NS.
1= motor
2= sensory
What are schwann cells?
support cells that produce myelin sheath that insulate the axon and allows AP to travel faster. Allow axon to be more physically robust.
What are the nodes of Ranvier?
small spaces on the axon between schwann cells.
PNS only has what two types of cells?
motor and sensory
The CNS has what specific type of cell?
interneuron
-perform integration
-some simple some complex
what are nerves?
bundles of axons in the PNS.
what are nerve tracts?
bundles of axons in CNS
What is ther intervertebral foramina?
where spinal nerves exit the vertebral canal between vertebrae
What is the dorsal root ganglion?
lump on dorsal root that is formed by cell bodies of all sensory neurons at spinal level.
what is ganglion?
term for group of neuron cell bodies in PNS.
what is a nucleus?
group of neuron cell bodies in CNS
What type of axons does the ventral root contain?
motor axons
what type of axons does the dorsal root contain?
sensory axons
