Chapter 14 Flashcards
Nervous system
- communication and control system.
- divided into structural and functional categories
How many structural organization?
Central nervous system (CNS)
Peripheral nervous system (PNS)
How many functional organization?
Sensory (afferent) division
Motor (efferent) division
Sensory Division (composed of two)
(INPUT)
somatic sensory—touch, pain, pressure, vibration, temperature, and proprioception
Visceral sensory- blood vessels to the CNS
Motor Division ( composed of two)
(OUTPUT)
somatic motor- AKA voluntary nervous system
regulates smooth muscle, cardiac muscle, and glands
autonomic motor component -regulates smooth muscle, cardiac muscle, and glands
Nerve Cells
Neurons- excitable cells that initiate and transmit nerve impulses
Glial cells- are nonexcitable cells that support and protect the neurons
Cell Body
control center
Dendrites
Dendrites are short
Dendrites conduct nerve impulses toward the cell body; receive input and then transfer it to the cell body
Axon
are larger
Most neurons have only one axon.
Where do Interneurons lie?
within the CNS
Glial Cells (GLADIATOR)
occur within CNS and PNS.
Glial cells physically protect and help nourish neurons, and provide an organized, supporting framework for all the nervous tissue.
Pg. 421
Functions of Glial Cells
Forming a structural network.
Replacing damaged neurons.
Assisting neuronal development.
What is Myelination?
process by which part of an axon is wrapped with a myelin sheath
Axon Regeneration (PNS) depends on 3 factors
- the amount of damage
- secretion of nerve growth factors
- distance between the site of the damaged axon and the effector organ
How many connective tissue wrappings does a nerve have?
3
What do PREsynaptic neurons do?
Presynaptic neurons transmit nerve impulses along their axonal membranes toward a synapse
Neurotransmitters are released only from….
plasma membrane of the presynaptic cell
What is in CNS?
brain and spinal cord
What is in PNS?
cranial nerves, spinal nerves, ganglia
What does an Axon do?
transmits a nerve impulse away from the cell body toward another cell
Interneurons are…..
multipolar
interneurons facilitate communication between…..
sensory and motor neurons
What does a neuron typically have?
a neuron has a cell body, dendrites, and axons
What does a myelin sheath do?
The myelin sheath supports, protects, and insulates an axon.
Endoneurium (connective tissue wrapping 4 nerve)
a delicate layer of loose connective tissue
Perineurium (connective tissue wrapping 4 nerve)
perineurium - a cellular and fibrous connective tissue layer that wraps groups of axons into bundles called fascicles
Epineurium (connective tissue wrapping 4 nerve)
epineurium - a superficial connective tissue covering
What does a synapse do?
transmits a nerve impulse at a specialized junction with another neuron
What do POSTsynaptic neurons do?
conduct nerve impulses through their dendritic and cell body membranes away from the synapse
Neurotransmitters binds to receptor proteins found only….
on the plasma membrane of the postsynaptic cell
What two factors influence the rate of conduction?
the axon’s diameter and the presence/ absence of a myelin sheath.
