Nervous Tissue Flashcards
1
Q
CNS
A
- central nervous system
- brain and spinal cord
- receives sensory input from periphery
- interprets info and sends output to periphery (motor response, secretion)
2
Q
PNS
A
- peripheral nervous system
- everything outside CNS: cranial nerves, spinal nerves, ganglia, enteric plexuses in small intestine, sensory receptors in skin, etc.
- separated into somatic and autonomic NS
3
Q
somatic NS
A
- conscious control
- contains afferents (sensory neurons) and efferents (motor neurons)
4
Q
autonomic NS
A
- unconscious control
- separated into sympathetic and parasympathetic NS
5
Q
components of neurons
A
- soma & nissl bodies
- dendrites
- axon
- myelin (nodes of Ranvier)
- synaptic end bulbs
6
Q
properties of neurons
A
- neurons don’t generally divide
2. electrically excitable –> turns electrical signal into chemical signal
7
Q
What do neurons synapse on?
A
- other neurons
- glands (release secretions)
- muscle (contract)
8
Q
multipolar neuron
A
- cell body has numerous dendrites coming off it
- majority of neurons in brain and spinal cord
9
Q
bipolar neuron
A
- single dendrite coming off cell body one way and axon coming off on other side
- found in special sensory organs
10
Q
pseudo-unipolar neuron
A
- one process coming off cell body, then branches into peripheral (dendrites) and central (axon) processes
- was bipolar during development
- found in peripheral NS –> primary neurons of sensations
11
Q
bundle of axons CNS vs. PNS
A
- CNS: tract
- PNS: nerve
12
Q
types of neuron axonal transport
A
- anterograde
- retrograde
- fast vs. slow
13
Q
anterograde transport
A
- uses kinesin to transport material from cell body (- end) to end of axon (+ end)
14
Q
retrograde transport
A
- uses dynein to transport material from end of axon (+ end) to cell body (- end)
- items brought back are recycled/degraded
15
Q
fast vs. slow transport
A
- smaller items (NT) –> fast
- bulkier items (cytoskeletal elements) –> slow
16
Q
axon
A
- signal leaves cell body and travels down this
- sends nerve impulse
- splits up into axon terminals with synaptic end bulbs
- insulated by myelin
17
Q
myelin
A
- speeds up conduction
- present in nodes (nodes of Ranvier)
- some neurons do not have myelin
18
Q
mechanism of chemical synapses
A
- synaptic bulb contains lots of mitochondria –> very energy dependent process
- vesicles containing NT migrate to synaptic bulb and fuse with PM
- release NT into synaptic cleft
- NT interacts with receptors on post-synaptic cell (located in junctional folds of muscle cells) –> excites or inhibits
19
Q
synaptic end bulbs
A
- pre-synaptic terminal
- contains lots of vesicles packaged with neurotransmitters
- released into synaptic cleft to transmit chemical signal
20
Q
astrocytes
A
- lots of projections in all directions
- intermediate filaments made up of Glial Fibrillary Acidic Protein (GFAP)
- attached to both neurons and blood vessels –> contributes to blood brain barrier (provides protection to neurons)
- metabolically support neurons
- release neurotrophic factors to keep neurons healthy
- can divide, not electrically excitable
- brought out by GFAP stain
21
Q
oligodendrocytes
A
- myelinate axons in CNS
- can extend processes to multiple neurons
22
Q
microglial cells
A
- gobble foreign invaders (immune function)
- can turn into macrophages
- brought out by silver stain
23
Q
ependymal cells
A
- responsible for lining cavities with fluid filled spaces
- helps maintain and produce cerebrospinal fluid (CSF)
24
Q
ventricles (brain)
A
- fluid filled cavities filled with CSF
- areas lined with ependymal cells
- have ciliary processes that extend into fluid
25
Schwann cells
- myelinates similarly to oligodendrocytes
- some repairing of axon possible
- create scaffolding to keep region of where axon was
26
satellite cells
- similar to astrocytes
- surround pseudo-unipolar cells
- provide protection and metabolic support
27
myelination in CNS vs. PNS
CNS: oligodendrocytes can myelinate multiple segments of a single axon or multiple axons at once
PNS: Schwann cells can only myelinate one segment
28
nodes of Ranvier
- myelin not continuous --> in segments
- much faster way of transmitting signal
- MS affects oligodendrocytes in CNS
- Guillain-Barre affects Schwann cells in PNS
- stained by Osmic Acid stain
29
white matter
- myelinated and unmyelinated axons
- lipid protein of myelin looks white
- inner portions of brain
- outer portions of spinal cord
30
gray matter
- primarily neuronal cell bodies, dendrites, unmyelinated axons, and neuroglia
- outer portions of brain
- posterior and lateral horn of spinal cord
31
organizational hierarchy (CT layers) of peripheral nerve
- endoneurium: CT layer around individual nerve fibers (axons)
- perineurium: CT layer around bundles of nerve fibers (fascicles)
- epineurium: CT layer around bundles of fascicles of nerve fibers (nerves)
32
ganglion
- collection of cell bodies
i. e. dorsal root ganglia --> collection of pseudo-unipolar cell bodies of somatic NS
- surrounded by satellite cells that help support cell bodies
33
organization of meninges
- central CT
- around brain and spinal cord
- pia mater (innermost layer)
- arachnoid mater (middle layer)
- dura mater (outermost layer)
34
Pia mater
- follows grooves and contours of brain
- major blood vessels also filled with CSF
- subarachnoid hemorrhage would be above Pia mater in subarachnoid space
35
sympathetic NS
- "fight or flight"
36
parasympathetic NS
- "rest and digest"
