Nerve Tissue Flashcards
(24 cards)
From what embryonic structures do the CNS and PNS develop?
CNS develops from the neural tube;
PNS develops from the neural crest cells
What are the 3 structural classes of neurons and where are they found?
Which one is the most common?
- Bipolar: found in retina, olfactory mucose, and inner ear (eye, nose, ear to remember)
- Multipolar: Most common
- Pseudounipolar: found in spinal ganglia and many cranial ganglia
What are the definitions of anterograde and retrograde flow?
What are the 2 proteins involved in the transport of these “flows”?
Anterograde flow: macromolecules/organellse made in cell are transported to axon terminals
Retrograde flow: Particle uptake via endocytosis;
Dynein(goes to microtubule - end (usually cell center) and
kinesin goes to microtubule + end
What are the 4 types of glial cells in the CNS and the 2 types of glial cells in the PNS?
CNS: 1.Oligodendrocytes 2.Astrocytes 3.Ependymal cells 4.Microglial cells
PNS: 1.Schwann cells 2.Satellite cells
What is the most numerous cell in the CNS?
What is their function?
Astrocytes;
They function as part of the blood-brain barrier, and form “perivascular feet” on blood vessels.
The also form scar tissue
What types of astrocytes are found in the white and gray matter of the brain?
Fibrous astrocytes are in the white matter of brain,
Protoplasmic astrocytes are in the gray matter of the brain
What are corpora amylacea?
intracytoplasmic bodies that develop in astrocytic processes with advancing age. They have not pathological significance but can be used to identify organ cells
Where are satellite cells located and what is their function?
They surround neuron cell bodies w/in ganglia;
They supply nutrients to surrounding neurons (in the PNS) and act as protective, cushioning cells.
What do oligodendrocytes do?
They produce myelin sheath and may myelinate multiple surrounding axons (IN THE CNS).
What do Schwann cells do?
They myelinate axons in the PNS.
NOTE: They can only myelinate one axon, but each axon can be myelinated by several cells
What do microglia cells do?
They are phagocytic cells (scavengers) that are important for inflammation and repair.
NOTE: They are the primary site of HIV infection of the CNS.
Where are ependymal cells found?
What is their function?
How can they be distinguished?
They line the VENTRICLES of the brain and the CENTRAL CANAL of the spinal cord;
They manufacture CSF;
They have cilia and microvilli on their apical surface
What does gray and white matter contain?
Gray: UNmyelinated axons, NEURONS, dendrites, glial cells
White: myelinated axons, glial cells, NO NEURONS
Where are gray and white matter located in the brain and spinal cord?
Brain: Gray matter forms cerebellar cortex on outside, white matter is beneath it;
Spinal cord: White matter on OUTSIDE, gray matter forms central H
What are the layers of the meninges from outer to inner?
Dura mater, subdural space, arachnoid mater, subarachnoid space (contains blood vessels), pia mater, cerebral cortex;
Astrocyte foot processes line the ____ membrane of the ____.
basement membrane of the pia mater
What is the choroid plexus?
How can you identifly this?
It is a plexus formed by folds of the pia mater where CSF is made.
Found in the 3rd and 4th ventricles, it consists of modified ependymal cells that manufacture CSF.
It is a loose connective tissue rich in capillaries covered by simple cuboidal epithelium
What is the difference b/w a nerve and nerve fiber?
A nerve is a group/bundle of nerve fibers covered by connective tissue.
Nerve fiber is an axon or a collection of axons and any surrounding sheaths (can be myelinated or unmyelinated)
Unmyelinated nerve fibers are ___ schwann cells
Embedded in clefts in cytoplasm of schwann cells
What are the 3 layers of connective tissue covering of nerves?
Endoneurium, perineurium, epineurium
A bundle of nerve fibers wrapped by the perineurium is called a ___.
How are perineurium cells joined together?
Fascicle;
Joined by tight junctions that isolate the nerve by passage of most macromolecules
What nervous system are ganglia a part of?
What are ganglia?
What are they for?
Part of PNS, they are a collection of neuronal cell bodies and their supporting structures;
They are relay stations for SENSORY input and AUTONOMIC information
What is the difference b/w dorsal root ganglia and autonomic ganglia?
Dorsal root ganglia (aka spinal ganglia) contain cell bodies of SENSORY (AFFERENT) nerves
Autonomic ganglia contain ell bodies of autonomic nerves (sympathetic and parasympathetic)
what is a meissner’s corpuscle and pacinian corpuscle?
Meisner’s corpuscle is a touch sensor in the skin;
Pacinian corpuscle is a deep pressure sensor
