Nervous System Part II Flashcards
sites of functional apposition where signals are transmitted from one neuron to another or from a neuron to another type of cell
SYNAPSES
Classification of site of synaptic contact:
Axodendritic synapses
Axosomatic synapses
Axoaxonic synapses
Dendrodendritic synapses
Classification of Method Of Signal Transmission:
Chemical synapse (neurotransmitter)
Electrical synapse
Method Of Signal Transmission:
Neuron-neuron; neuron-muscle
Chemical synapse (neurotransmitter)
Method Of Signal Transmission:
Delay by 0.5 ms
Chemical synapse (neurotransmitter)
Method Of Signal Transmission:
Gap junctions; nearly instantaneous transmission
Electrical synapse
Method Of Signal Transmission:
Less common
Electrical synapse
Common neurotransmitters:
Located in Myoneural junctions; all parasympathethic synapses; prenganglionic sympathetic synapses
Acetylcholine
Common neurotransmitters:
Activates skeletal muscle, autonomic nerves, brain functions
Acetylcholine
Common neurotransmitters:
Located in Postganglionic sympathetic synapses
Norepinephrine
Common neurotransmitters:
increases cardiac output
Norepinephine
Common neurotransmitters:
Located in CNS; presynaptic sensory and cortex
Glutamate
Common neurotransmitters:
Most common excitatory neurotransmitter of CNS
Glutamate and y-Aminobutyric acid
Common neurotransmitters:
Located in the CNS
y-Aminobutyric acid
Dopamine
Serotonin
Aspartate
Enkephalins
Endorphins
Common neurotransmitters:
Inhibitory and excitatory, depending on receptor
Dopamine
Common neurotransmitters:
inhibitory
glycine
Common neurotransmitters:
pain inhibitor; mood control; sleep
serotonin
Common neurotransmitters:
excitatory
aspartate
Common neurotransmitters:
analgesic; pain suppression
enkephalins and endorphins
individual axons enveloped by a myelin sheath
NERVE FIBERS
produced by oligodendrocytes (CNS) and Schwann cells(PNS)
MYELIN SHEATH
not continuous along the length of the axon but is interrupted by gaps called nodes of Ranvier.
MYELIN SHEATH
can be extracted by standard histological techniques. Methods using osmium tetroxide preserve the myelin sheath and stain it black.
MYELIN SHEATH
regions along the axon that lack myelin and represent discontinuities between adjacent Schwann cells or oligodendrocytes.
Nodes of Ranvier
Nodes of Ranvier:
axon at the nodes of Ranvier is covered by interdigitated cytoplasmic processes of adjacent Schwann cells that protect the myelin-free surface of the axon
PNS
Nodes of Ranvier
foot plate of an astrocyte.
CNS
contains mostly myelinated nerve fibers but also some unmyelinated fibers and neuroglial cells.
White matter
contains neuronal cell bodies, many unmyelinated fibers, some myelinated fibers, and neuroglial cells.
Gray matter
Spinal cord gray matter appears in the shape of an ____ in cross-sections of the spinal cord
H
is located at the periphery (cortex) of the cerebrum and cerebellum.
Brain gray matter
lies beneath the gray matter in these structures
White matter
consists of flask-shaped Purkinje cells.
Purkinje cell layer (cerebellar cortex only)
central nucleus, highly branched (arborized) dendrites, and a single myelinated axon
Purkinje cell layer
may receive several hundred thousand excitatory and inhibitory impulses to sort and integrate
Purkinje cell layer
clear fluid produced primarily by cells of the choroid plexus in the ventricles of the brain
Cerebrospinal Fluid (CSF)
circulates through the ventricles, subarachnoid space, and central canal, bathing and nourishing the brain and spinal cord; shock-absorbing cushion
Cerebrospinal Fluid (CSF)
90% water and ions; it contains little protein, occasional white blood cells, and infrequent desquamated cells.
Cerebrospinal Fluid (CSF)
continuously produced and is reabsorbed by arachnoid granulations that transport it into the superior sagittal sinus. If reabsorption is blocked, hydrocephalus may occur.
Cerebrospinal Fluid (CSF)
Are dendritic nerve endings located in the skin, fascia, muscles, joints and tendons
NERVE ENDING RECEPTORS
Respond to stimuli related to touch, pressure, temperature and pain
NERVE ENDING RECEPTORS
Nerve ending which are for light touch
Meissner’s Corpuscle
Found in dermal papilla of skin
Meissner’s Corpuscle
For deep touch
Paccinian Corpuscle
Found in skin and pancreas
Paccinian Corpuscle
