Nervous Tissue

Questão	Responda
These cells conduct electrical impulses.	Neurons (nerve cells)
What is the special relationship between glial cells and neurons?	There can't be one without the other. Support cells for neurons aid in nerve cell function.
What type of cells support, nurture, and protect neurons?	Glial cells
What are 3 types of neurons?	bipolar, multipolar, and pseudounipolar
These neurons have a single axon and a single dendrite. They are located in sense organs.	Bipolar neurons
What type of neurons have single axon and multiple dendrites?	multipolar neurons
The most common type of neurons.	Multipolar neurons
These neurons have a single process that extends from cell body and branches into an axon and dendrite. They first develop in the embryo as bipolar cells whose axon and dendrite later fuse into a single process.	pseudounipolar neurons
These neurons are located in spinal and cranial ganglia.	pseudounipolar neurons
These neurons are coined as the "workhorse" neuron. They aid in moving muscles at the neuromuscular junction.	multipolar neurons
What are the two divisions of the nervous system?	anatomical divisions & functional divisions
What are the two primary neurons of the functional division of the nervous system?	afferent neurons & efferent neurons
What are the two anatomical divisions of the nervous system?	CNS & PNS
What two body parts make up the CNS?	brain and spinal cord
The PNS consists primarily of _____ ______ and _____.	peripheral nerves ganglia
Efferent neurons involve what types of networks?	somatic (voluntary) & autonomic (involuntary)
_____ receive stimuli from sensory cells, axons, or other neurons. They convert these signals into small electrical impulses which are transmitted to soma.	Dendrites
______ often have arborized terminals which permit a neuron to receive very large number of stimuli.	Dendrites
What are two other names for neuronal cell bodies?	soma, perikaryon
This portion of the soma lacks rough ER and ribosomes. It also contains microtubules and neurofilaments.	axon hillock
These move organelles within a cell, projecting direct axonal flow.	microtubules
Part of cytoskeleton, ____ are intermediate filaments of the soma.	neurofilaments
This portion of the soma is large with dispersed chromatin and a large nucleolus.	Nucleus
Describe the stain of an axon.	lack of staining because no Golgi or RER, indicating proteins (darkly stained); traveling down axon hillock cannot be seen also
_____ conduct impulses away from the soma to the axon terminals. May also branch.	Axons
While dendrites taper, ____ retain a constant diameter along their course. The diameter is proportional with the size of a cell body, but length is highly variable.	axons
The name for neuronal cytoplasm, which is devoid of RER.	axoplasm
The term for the axonal plasma membrane.	axolemma
This structure of a neuron terminates in axon terminals from which impulses are passed to another neuron or other type of cell (muscle or gland).	Axon
An individual axon enveloped by a myelin sheath.	nerve fiber
How are myelin sheaths produced?	Oligodendrocytes in the CNS Schwann cells in the PNS
Where are oligodendrocytic myelin sheaths found?	CNS
Where are myelin sheaths produced by Schwann cells found?	PNS
How are lipoprotein sheaths formed?	by several layers of plasma membrane of a Schwann cell wrapping around an axon
Segments covered by one Schwann cell are separated by _____ ___ _____.	Nodes of Ranvier
How do lipids stain?	Not well, so you must identify a lack of staining. Use a special stain that adds dark circles around the layers of Schwann cells being wrapped by lipoproteins.
Describe the thickness proportion between axons and myelin sheaths.	The thicker the axon, the thicker the myelin sheaths
Which is faster impulse: a myelinated axon or unmyelinated axon?	myelinated axon
How are unmyelinated axons insulated?	by astrocyte processes
Where are unmyelinated axons located in the PNS?	embedded in Schwann-cell cytoplasm
The most common demyelinating disease.	Multiple Sclerosis
What is this disease? - Unknown etiology; immune/viral factors suspected - Multiple areas of demyelination in brain and spinal cord; progressive - Weakness of lower extremities, visual problems, sensory disturbances -CNS system	Multiple Sclerosis
Which myelin disorder is found in the CNS? PNS?	CNS = Multiple Sclerosis PNS = Guillain-Barré Syndrome
What is this disease? - PNS system - Acute inflammatory demyelinating disease involving peripheral nerves - Often preceded by viral infection, immunization, or allergic reactions - autoimmune etiology - Ascending muscle weakness and paralysis (moving from lower extremity upward) - Most patients recover but respiratory failure may lead to death	Guillain-Barré Syndrome
This connective tissue is fibrous, dense tissue that forms the external coat of nerves.	Epineurium
This layer of modified dense connective tissue surrounds each bundle (fascicle) of nerve fibers. Its inner surface consists of flattened epithelioid cells joined by tight junctions (barrier function).	perineurium
This thin layer of loose connective tissue surrounds individual nerve fibers.	endoneurium
This matter contains mainly myelinated but also some unmyelinated nerve fibers.	white matter
What is the function of pyramidal neurons in the brain?	They give spatial recognition.
What is the function of purkinje fibers/cells in the brain?	proper movement in coordinated way; pain reception and awareness
What are two important specialized receptors in the brain?	Meissner's corpuscles & Pacinian corpuscles
Name this specialized receptor. - Encapsulated receptors in dermis (skin) - fingertips - CT capsule enveloping nerve terminal and its Schwann cell - Fine touch	Meissner's corpuscles
Name this specialized receptor. - Encapsulated receptor in dermis, joints, and mesenteries - Multilayered capsule of fibroblasts, collagen, and fluid, surrounding a nerve terminal - Pressure, touch, vibration	Pacinian corpuscles

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	Criado por Kristina Redd mais de 7 anos atrás