Chapter 13 - Neural Tissue Flashcards
What are the two communication systems?
Nervous system and endocrine system.
What does the nervous system do?
Coordinate all body systems and electrochemical signaling.
What does the endocrine system use for signaling?
Hormones.
What is the general make-up of the nervous system?
CT, BVs, neurons, and neuroglia.
What are the 2 divisions of the nervous system?
Central nervous system (CNS) and peripheral nervous system (PNS).
What comprises the CNS?
Brain and spinal cord.
What comprises the PNS?
Cranial and spinal nerves.
CNS characteristics?
Brain and spinal cord, covered by meninges, starts as a hollow tube, bathed in cerebro spinal fluid, and integration center.
PNS charcteristics?
Consists of cranial and spinal nerves that contain both sensory and motor fibers, connects CNS to muscles, glands & all sensory receptors, and brings info to and from the CNS.
What are the two types of PNS?
Afferent division (sensory) and efferent division (motor).
What are the two divisions of the efferent division?
Somatic division (conscious) and autonomic division (unconscious).
General functions of nervous system?
Receptor: detect stimuli, sensory: afferent PNS, integrative: CNS, motor: efferent PNS, and effector: muscle/gland.
What are the types of nervous tissue?
Neurons and neuroglial cells.
Neuron characteristics?
Structural & functional units, excitable, and amitotic.
Neuroglial cell characteristics?
Accessory cells and act like connective tissue.
What are the three major structures of neurons?
Soma (cell body), dendrites, and axon.
Is the soma mononucleated or multinucleated?
Mononucleated.
What does the soma consist of?
Nissl bodies, axon hillock, perikaryon, and neurofibrils.
Nissl bodies characteristics?
Ribosome clusters; give gray color.
Axon hillock characteristics?
Connects soma to axon.
Perikaryon characteristics?
Region around the nucleus.
Neurofibrils characteristics?
Cytoskeleton that extend into dendrites/axons; gives shape.
Dendrite characteristics?
Respond to neurotransmitters, short, branched, unmyelinated, specialized for contact with other neurons, and conducts impulses toward the cell body.
Axon characteristics?
Only 1/cell, conducts nerve impulses away from soma, can give off collaterals, wrapped in myelin sheath, end in synaptic terminals, produce neurotransmitters.
The axon may contact what?
Another neuron, muscle fibers, and glands.
Another name for axonal transport?
Axoplasmic flow.
What does axonal transport do?
Move cellular materials (not signals) through the axon.
What are the 2 types of axonal transport?
Anterograde and retrograde.
What is anterograde axonal transport?
Away from soma; neurotransmitters, organelles, and nutrients.
What is retrograde axonal transport?
Toward soma; degraded materials to be recycled & extracellular substances
What is the axoplasma?
Cytoplasm of an axon.
What does the axoplasma consist of?
Few organelles and cytoskeletal proteins.
What do cytoskeletal proteins do?
Form cytoskeleton, maintain shape, and generate axonal transport.
What is axolemma?
Plasma membrane of an axon.
What does the axolemma consist of?
Collaterals, telodendria, and synaptic terminal.
What are collaterals?
Side branches.
What are telodendria?
Terminal extensions.
What are synaptic terminals?
Where the neuron contacts the postsynaptic cell.
How are neurons classified?
Based on the number and morphology of dendrites.
What are the types of neurons?
Anaxonic, bipolar, unipolar, and multipolar.
What are anaxonic neurons?
Small neurons and axons cannot be distinguished from dendrites (CNS, especially interneurons that coordinate special senses.)
What are bipolar neurons?
Several small dendrites converge onto one, dendrite and axon separated by soma, and unmyelinated (sensory neurons of special sensory organs).
What are unipolar neurons?
Several small dendrites converge onto one large one, dendrite and axon continuous, and usually myelinated (majority of sensory neurons in PNS).
What is another name for unipolar neurons
Pseudo-unipolar.
What are multipolar neurons?
Many dendrites extend from soma, long axon, myelinated (majority of motor neurons in PNS and spinal interneurons in CNS).
What are the functions of afferent neurons?
Sensory