Ch. 11 Nerve Tissue Flashcards
1
Q
- efferent of motor nerves
- afferent or sensory
A
- away from CNS to salivary glands, ms, etc
- to CNS (receive from nose, eyes)
2
Q
- somatic nervous sys
- autonomic nervous sys
A
- provides sensory and motor innerve to all parts except viscera, smooth ms, glands
- provides efferent invol motor innerv to smooth ms, heart, and glands. also provides afferent sensory innerv fr viscera (pain and autonomic reflex)
3
Q
Supporting cells
A
- in cns: neuroglia
- in pns: schwann cells and satellite cells
4
Q
- sensory neurons
1. somatic afferent fibers
2. visceral afferent fibers - motor neurons
- interneurons
A
- convey pain, temp, touch, and pressure from body surface
- transmit impulses of pain and other sensations from mucous membranes, glands and blood vessels
- convey impulse from cns to effector cells
- form communicating and integrating network bet sensory and motor neurons
5
Q
- multipolar
- bipolar
- unipolar
A
- one axon and 2 or more dendrites (motor neurons/ interneurons)
- one axon and one dendrite (retina of eye)
- have one process, the axon (sensory neurons)
6
Q
Cell body or perikaryon
A
- like a protein-producing cell
- have much rER as a NISSL body stacks and free ribosomes
- also has mitochondria, Golgi, lysosomes, microtubules, neurofilaments, transport vesicles, inclusions
- neurons do not dived, but subcellular components turn over regularly
7
Q
- axodendritic
- axosomatic
- axoaxonic
A
- axons and dentrites
- axons and cell body
- axons and axons
*Boutons en passant, an axon makes several button-like contacts w/ the receptor portion of the neuron
8
Q
synaptic transmission
A
- presynaptic membrane depolarization induces…
- brief opening of calcium channels
- calcium influx promotes exocytosis of synaptic vesicles with…
- release of neurotransmitter
- neurotransmitter reacts w/ receptors and…
- causing Na channels to open in that membrane, allowing Na to enter the neuron, causing others to open, generating a nerve impulse. - promotes postsynaptic membrane depolarization
9
Q
-excitatory synapse
A
- release of acetylcholine, glutamine and serotonin. opening Cation channels for Na influx leading to action potention and generate impulse.
- release of GABA or glycine, opening anion channels for CL influx. causing action potential to become more difficult.
10
Q
Acetylcholine (Ach)
A
- serves neurotransmitter bet axons and effectors or striated muscle in the ANS
- are called Cholinergic neurons or receptors
- 2 classes:
1. muscarinic Ach receptor
2. Nicotinic Ach Receptor
11
Q
Catecholamines
A
- Norepinephrine (NE), Epinephrine (EPI), Dopamine (DA)
- Adrenergic neurons
- EPI secreted by CNS and adrenal medulla during Fight-or-flight
12
Q
Serotonin, GABA, Glutamate, Aspartate and Glycine
A
-other neurotransmitters
- High-affinity reuptake: removal of neurotransmitter following its release into the synaptic cleft
- needed to limit the duration of stimulation or inhibition of postsyn membrane
13
Q
-myelin sheath
A
- is a thin layer of Schwann cell cytoplasm called the sheath of Schwann or neurilemma
- contains the nucleus and most of organelles of Schwann cells
14
Q
internodal segment
A
-the myelin between 2 sequential nodes of Ranvier
15
Q
satellite cell
A
- analogous to schwann but doesn’t make myelin
- small cuboidal cells that surrounds the neuronal cell body of ganglia
- help est and maintain a controlled micro-environment around the neuronal body in the ganglion
- electrical insulation
- pathway for metabolic exchange
16
Q
Neuroglia:
- oligodendrocytes
- astrocytes
- microglia
- ependymal cells
A
- small cells forming and maintaining myelin in the CNS. aligned in rows between axons, fewer processes
- provide physical and metabolic support for the neurons of the CNS
- protoplasmic: gray
- fibrous: white - inconspicuous cells w/ small, dark, elongated nuclei that possess phagocytotic properties
- column-shaped cells line brain ventricles and canal of spinal cord, containing cilia and microvilli to absorb cerebrospinal fluid.
- the modified ependymal cells and associated capillaries are called choroid plexus.
17
Q
Saltatory or Discontinuous Conduction
A
- nerve impulse jumping from node to node
- conduction is faster on axons of greater diameter and myelinated
18
Q
origin of nerve tiss
- CNS
- PNS
A
- from neuroectodermal cells of neural tube
- from neural crest
19
Q
Connective tiss components of peripheral nerve
- endoneurium
- perineurium
- epineurium
A
- loose conn tiss surrounding each individ nerve fiber
- specialized conn tiss surrounding each nerve fascicle
- dense, irregular conn tiss that surrounds a peripheral nerve and fills the spaces between nerve fascicles.
20
Q
31 segments of spinal nerves
A
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
21
Q
- white matter
2. gray matter
A
- peripheral substance contains myelinated and unmyelinated axons
- surrounding central canal. containing neuronal cell bodies and dendrites. synapses only occur here.
*cell bodies of efferent neurons are on ventral horn of gray matter
22
Q
Classification of receptors
- extereceptors
- enteroreceptors
- propioceptors
A
- from external environ (temp, touch, smell, sound or vision)
- from within the body (degree of filing of stretch of bladder)
- from within the body, providing sensation of body position and muscle tone and movement
23
Q
Classifications of autonomic nervous system
A
- sympathetic
- parasympathetic
- enteric division
1 and 2 supply the same organs but are antagonistic
24
Q
Organization of CNS
- gray matter
- white matter
A
- is the site of synapses, forming an outer covering or cortex. nuclei seen in the deep portions of cerebrum and cerebellum.
- many of the axons going to, or coming from a specific location are grouped into bundles called TRACTS
25
Q
- Neuropil
- Brain stem
- Nuclei
A
- the meshwork of axonal, dendritic and glial processes associated with the gray matter
- is not clearly separated into regions of gray and white matter
- appear as islands surrounded by more or less distinct tracts of white matter
26
Q
conn tiss of CNS
A
- dura mater-outermost, thick sheet of dense conn tiss., continuous w/ periosteum of skull.
- arachnoid-delicate sheet
- contains trabeculae of loose conn. tiss fibers containing elongated fibroblast - pia mater-delicate. rests on brain surface and spinal cord, continuous w/ perivascular conn tiss sheath of blood vessels of brain and spinal cord
*all covered by thin, squamous epithelial layer
27
Q
Wallerian/Antegrade degeneration
A
- degeneration of axon distal to a site of injury
- in PNS, in a few days
- in CNS, several weeks
28
Q
Chromatolysis
A
- loss of Nissl substance from the cell body
- the changes in cell body are proportional to the amt of axoplasm lost by the injury
29
Q
- scar formation
- regeneration
A
- in PNS, connective tiss and Schwann cells form scar tiss and the gap bet the ends of a severed or crushed nerve
- Schwann cells divide and develop cellular bands that bridge a newly formed scar. the bridges serve as guides for regenerating axons to grow across the scar
- if the axonal sprouts do not rest contact w/ the bridge of Schwann cells, the sprouts grow in a disorganized manner, and the muscle remains atrophic
