Physio II Lecture 1B Flashcards
The nervous system is divided into three parts. Name them
CNS, PNS, ANS
The CNS consists of _____
Structures arising directly from the neural tube. Includes: Brain and spinal cord
The PNS consists of ______
cranial nerves and spinal nerve
The ANS consists of_______
sympathetic and parasympathetic
Define CNS
the CNS consists of unpaired, bilaterally symmetrical structures extending along the longitudinal axis of the midsagittal plane of the body
What is a brain?
Sorts through and properly routes incoming sensory info. Initiates controls and coordintes most muscular activity except simple reflexes
Site of origin of 12 cranial nerve pairs
What 4 pairs of cranial nerves carry parasympathetic fibers?
III, VII, IX, X
What are the general functional categories of the brain
sensory
motor
cognitive
Define spinal cord
It is the first CNS structure encountered by most incoming sensory info except sensory fibers in cranial nerves. It is the last relay station for most motor information except ANS motor fibers. It is the site of coordination of most reflex arcs
Define peripheral nervous system
It is made up of transmission pathways carrying info between the CNS an external/internal environment. Has afferent pathways and efferent pathways
What carries info to the CNS
afferent (sensory) pathways
What carries information FROM CNS
efferent (motor) pathways
How many cranial nerves are included in the PNS?
12
How many spinal nerves are included in the PNS?
31 of the PNS
PNS has sensory receptors in _____
the skin and wall of the gut tube as well as in tendons and skeletal muscles
PNS motor end plates are between ______
motor neurons and skeletal muscle fibers
ANS may be considered a subdivion of _________
the PNS
ANS is entirely _________
motor
ANS innervates ______
smooth muscle and glands (viscera)
ANS sympthetic system is also called the ______ and ________
fight or flight
also called thoracolumbar
ANS prasympathetic is called _____ and _______
feed and breed
also called craniosacral
What is the cell body of a neuron?
It is part of a neruon that encloses the nucleus and other organelles necessary to maintain and repair the neuron
Has a trophic unit and perikaryon
What are dendrites of a neuron?
Branches off the cell body that carry information to the cell body: Receptive unit
Characteristics: -usually several to many dendrietes per neuron
-relatively short, compared to the axon
-often branched
**have receptors for neurotransmitters
**conduct local potentials
What is the axon of a neuron?
The conductive unitthe neuron that carries info to another neuron or muscle cell
What are axon characteristics?
Usually relatively long
Single (one per neuron)
Conducts action potentials (nerve impulse)
Releases neurotransmitters
What are telodendria?
- Short branched processes at axon ends
- They give off endings called terminal boutons
axons may have what type of branches?
collateral
what is the cell membrane of the axon called?
axolemma
what is the cytoplams of the axon called?
axoplasm
what does the axon contain?
mitochondria, neurofilaments, and neurotubules
axon is covered by a __________
neurolemma
neurolemma is made up of _________ and is often________. And the ______ is formed by ___ ____
The neurolemma is made up of Schwann cells and is often myelinated. And the myelin is formed by Schwann cells
What is the ONLY part of the neuron that can be mylinated? Is this part always myelinated?
The Axon
Not all axons are myelinated, even though they are covered by schwann cells
What is aggregation of dendrites and nerve cell bodies in CNS called?
Nucelus
What is aggregation of dendrites and nerve cell bodies in PNS called?
ganglion
What are bundle of fibers (axons) in the PNS called?
Nerve
What are bundle of fibers (axons) in the CNS called?
Tract
What is the tract in the CNS that crosses from one side to the other called?
commissure
What are areas of myelinated axons called?
white matter
What are areas of unmylenated axons, cell bodies, and dendrites called?
gray matter
What are two spinal nerve branches (rami)?
dorsal primary rami and ventral primary ramus