Nerves, Ch 11 Flashcards
What are the two primary functional divisions/organization of the nervous system? How do they differ? Peripheral nervous system
The PNS sensory division detects stimuli and transmit information from receptors to the CNS.
The PNS motor division initiates and transmit information from the CNS to effectors.
What are the two anatomical divisions/structural organization of the nervous system?
The central nervous system consists of the brain and spinal cord. The peripheral nervous system consists of the spinal nerves and their branches/ganglia.
What three functions does the nervous system have?
Sensory, integrative, and motor.
Function of the NS that involves gathering information about the internal and external environment of the body.
Sensory functions
Afferent PNS
Functions of the NS that analyze and interpret the incoming sensory information and determine and appropriate response.
Integrative functions
Performed entirely by the CNS, mostly the brain
Functions of the NS that are the actions performed in response to integration.
Motor functions
Efferent division of the PNS
How many pairs of cranial and spinal nerves?
12 cranial
31 spinal
Division of the PNS that consists of neurons that carry general sensory signals from muscles, bones, joints, and the skin, as well as special sensory signals. 5 senses
Somatic sensory division
Consciously perceived
Division of the PNS that carries signals from viscera such as the heart, lungs, stomach, etc.
Visceral sensory division
Not consciously perceived
Division of the PNS that consists of neurons that transmit signals to skeletal muscles.
Somatic motor division Voluntary
Division of the PNS that consists of neurons that carry signals primarily to thoracic and abdominal viscera. Regulates secretion from certain glands, contraction of smooth/cardiac muscles. Homeostasis.
Visceral motor division
Autonomic nervous system
Involuntary
Neurons have these five features?
Excitability, conductivity, secretion, extreme longevity, amitotic
Meaning that at a certain point in a cell’s development, they lose their centrioles and after that lack ability to undergo mitosis.
Amitotic
The excitable cell type responsible for sending and receiving signals in the form of action potentials. Consist of three parts.
Neurons
Cell body, axon, dendrites
Neurons control center, enclosed by a plasma membrane with cytoplasm surrounding a nucleus with prominent nucleolus. Free and bound ribosomes. no centrioles.
Cell body of the neuron
Soma
Provide structural support for that extends out into the dendrites and axon of the neuron as well.
Neurofibrils
Receive input from other neurons, which they transmit in the form of electrical impulses to the cell body. The cell may have one or many.
Dendrites
These are termed either chromatophilic or Nissl bodies due to their dark color under a microscope.
Clusters of free and bound ribosomes in the cell body.
Cytoplasm within cell body
Perikaryon
Process emanating from the cell body that makes contact with other neurons, muscle cells, or glands. Generates and conducts action potentials. Nerve fiber.
Axon
Branches extending at right angles from the axon. Both the axon and these split at the ends to produce multiple fine telodendria (axon terminals).
Axon collaterals
Telodendria terminate in these, which communicate with a target cell. Each axon generally splits into 1000 or more of these.
Axon terminals
Synaptic knobs
The plasma membrane and cytoplasm of the neuron.
Axolemma
Axoplasm
Type of transport that relies on motor proteins in the axoplasm that consume Atp and move substances along the microtubules in what two ways?
Fast axonal/bidirectional transport
Retrograde (toward the cell body)
Anterograde (away from the cell body)
Neurons that have a single axon and typically multiple highly branched dendrites. Over 99% of neurons in the body. Widest variability in terms of shape and size. What division?
Multipolar neurons
Motor (efferent) neurons, interneurons
Neurons that have only two processes: one axon and one dendrite. Located in special sense organs in the PNS, such as the retina. What division?
Bipolar neurons
Sensory (afferent) neurons
Neurons that begin developmentally as bipolar, but their two processes fuse to give rise to a single axon which splits into the peripheral and central axons. Sensory neurons in the PNS, touch, pressure, etc. What does each axon do? What division?
Pseudo unipolar axons
Peripheral axon brings information from sensory receptors to the cell body
Central axon travels to the spinal cord away from the cell body.
Sensory (afferent neurons)
Association neurons. Relay messages within the CNS, primarily between sensory and motor neurons. Location of most information processing. Vast majority of neurons are these. Multipolar.
Interneurons
Clusters of cell bodies of neurons, most of which are in the CNS where they are called what? Within the PNS they are called what?
Nuclei in the CNS, tracts
Ganglia in the PNS, nerves
Nonexcitable cells that maintain the environment between neurons, protecting them, assisting in their functioning. Retain their ability to divide and fill in gaps when neurons die.
Neuroglia
10 times more abundant in the CNS than neurons, make up half the mass of the brain.
Four types of glial cells in the CNS?
Astrocytes
Oligodendrocytes
Microglia
Ependymal
Two types of microglia in the PNS?
Schwann cells
Satellite cells
Macroscopic cable-like bundle of parallel axons
Nerve
Layer of dense irregular connective tissue that wraps bundles of axons, fascicles and support the blood vessels.
Perineurium