Structural & Functional Organization of Nervous Tissue Flashcards
how many pairs of cranial nerves are there
12
where do cranial nerves emerge from
the base of the brain
how many pairs of spinal nerves are there
31 pairs
spinal nerves emerge form where
spinal cord
what are specialized cell that monitor the chain of the internal and external environment
Such as photoreceptors in the retina of the eye
Sensory receptors
what are Small masses of nervous tissue consisting of neuronal cell bodies that are located outside the brain and spinal cord
Ganglia
what are Extensive network of nerves that are located in the walls of the gastrointestinal tract that help regulate the digestive system.
Enteric Plexus
what are the three basic functions of the nervous system
Sensory function = afferent
Integrative function
Motor function = efferent
out of the 3 basic function of the Nervous system which one Detect internal and external stimuli and carry information into brain and spinal cord via cranial and spinal nerves
Sensory function (afferent)
out of the 3 basic function of the Nervous system which one deals with Perception and Analyzes and storing information to help lead to appropriate responses
Integrative function
out of the 3 basic function of the Nervous system which one is described as the integration occurs the brain may elicit motor response to muscles or glands (effectors) via cranial and spinal nerves.
Motor function
Nervous tissue consists of two cells
Neurons
Neuroglia
out of the two Nervous tissue which one Provide most of the unique functions of the nervous system
Neurons
out of the two Nervous tissue which one provides Function to provide support, nourishment, and protection
Neuroglia
what are the parts of the neuron
dendrites
cell body
axon
axon terminals
Parts of the Neuron:
what part contains the Nucleus, cytoplasm with typical organelles
Cell body
Parts of the Neuron:
what part is highly branched structures that carry impulses to the cell body
Dendrites
Parts of the Neuron:
what part Conducts away from cell body toward another neuron, muscle or gland and Emerges at cone-shaped axon hillock
Axon
Parts of the Neuron:
what part Contain synaptic vesicles that can release neurotransmitters
Axon terminals:
what are Structural Classes of Neurons
Multipolar
Bipolar
Unipolar
what are Structural Classes of Neurons Has several or many dendrites and one axon and is Most common type in brain and spinal cord
Multipolar
what are Structural Classes of Neurons Has one dendrite and one axon
Bipolar
what are Structural Classes of Neurons has fused dendrite and axon and Sensory neurons of spinal nerves
Unipolar
what are the Functional Classes of Neurons
Sensory = afferent
Motor = efferent
Interneurons = association neurons
what Functional Class of Neurons Convey impulses into CNS (brain or spinal cord)
Sensory = afferent
what Functional Class of Neurons Convey impulses from brain or spinal cord out through the PNS to
effectors (muscles or glands)
Motor (efferent)
what Functional Class of Neurons Located within the CNS and Transmit impulses between neurons, such as between sensory and motor neurons
Interneurons (association neurons)
what are the characteristics Neuroglia
Support, nourish, and protect neurons
Critical for homeostasis of interstitial fluid around neurons
Cells smaller but much more numerous than neurons
Make up about half the volume of the CNS
what are the Functions of Neuroglia
Do NOT generate or conduct nerve impulses
In case of injury or disease, neuroglia can multiply to fill in space formerly occupied by neurons
what are the type of Neuroglia
Astrocytes
Oligodendrocytes
Microglia
Ependymal
Schwann
Satellite cells
Astrocytes form what
blood brain barrier (CNS)
Oligodendrocytes produce what
myelin in CNS (CNS)
Microglia protects what
CNS cells from disease (CNS)
Ependymal cells form what
CSF in ventricles (CNS)
Schwann cells produce what
myelin around PNS neurons (PNS)
Satellite cells support what
neurons in PNS ganglia (PNS)
Most axon are surrounded by a what and for what purpose
myelin sheath
Insulates the axon and speeds up the nerve impulse
Myelin increases a what stages of birth
birth to maturity
Gaps in myelin along the axon are called
Nodes of Ranvier
What diseases destroy myelin sheaths
Multiple Sclerosis and Tay-Sachs
a cluster of neuron cell bodies are divided into what two subcategories
Ganglion
Nucleus
Cluster of cell bodies in PNS are referred to what
Ganglion
Cluster of cell bodies in CNS
Nucleus
Bundle of axons in PNS are called
Nerves
Bundle of axons in CNS are called
tract
white matter is Primarily
myelinated axons
what makes up grey matter
Cell bodies, dendrites, unmyelinated axons, axon
terminals, neuroglia
in the spinal cord what type of mater is identified by the “H” or “butterfly” shape
what type of matter surrounds the “H” or “butterfly” shape
grey matter
white matter
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Axons and dendrites in the PNS can be repaired if what
cell body is intact
and Schwann cells functional.
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even if cell body is intact Regeneration of CNS neurons is ______, why
limited
Inhibited by neuroglia and by lack of fetal growth-stimulator cues
Action potentials, or nerve impulses, allow for ?
communication between neurons
what is required for action potential
resting membrane potential
Ion channels
what is required for action potential
resting membrane potential
Ion channels
STIMULUS
characterize a resting membrane potential
charge difference across cell
membrane (polarization)
characterize Ion channels
Allow ions to move by diffusion from high to low concentration
Action potentials are part of a series of events that activate cell membranes where
neuron or muscle fiber
STIMULUS Triggers resting membrane to become more permeable to
Sodium (Na+)
STIMULUS Causes enough Na+ to enter cell so that cell membrane reaches threshold of ?
-55 mv
If threshold is reached what happens
an action potential arises(“all or nothing response”)
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what are the type of conduction
Continuous conduction
Saltatory conduction
which type of conduction is slower and In unmyelinated axons, currents flow across adjacent portions of the plasma membrane
Continuous conduction
which type of conduction In myelinated axons, Nodes of Ranvier allow impulses to “leap” from one node to the next
Saltatory conduction
Synapses allow neurons to communicate with
other neurons or effectors
how is Synaptic Transmission triggered
by action potential
what are the components of synapse
Presynaptic neuron = Sending neuron
Synaptic cleft = Space between neurons
Postsynaptic neuron =Receiving neuron
in a Synaptic Transmission Action potential arrives where
presynaptic neuron’s end bulb
describe what happens Action potential arrives at presynaptic neuron’s end bulb
(e) Opens voltage gated Ca2+ channels
1) Ca2+ flows into presynaptic cytosol
(f) Increased Ca2+ concentration causes exocytosis of
synaptic vesicles
(g) Neurotransmitter (NT) released into cleft
(h) NT diffuse across cleft and bind to receptors on the postsynaptic cell membrane
(i) NT acts as chemical trigger, opening ion channels which changes the voltage across the postsynaptic cell membrane
(j) Postsynaptic cell membrane may be depolarized or hyperpolarized, depending on which ions were admitted
(k) If threshold reached (-55mV) then postsynaptic AP
results and nerve impulse is triggered
(l) One-way transmission: Action potentials can only travel in one direction from dendrite to axon.
(m) NT removed from cleft via diffusion, destruction by enzymes such as Achase, or transport back into presynaptic cell (recycling)
what are the Neurotransmitters
Acetylcholine (ACh): Common in PNS
Amino acids
Modified amino acids
Neuropeptides such as endorphins
Nitric oxide (NO)
Central Nervous System consist of
Consists of the brain and spinal cord
where are the sources of thoughts, emotions, and memories
Central Nervous System
Peripheral Nervous System Includes all the nervous tissue where
outside the central nervous system Include the cranial nerves, spinal nerves, ganglia and sensory nerves
Peripheral Nervous System can be divided
Somatic nervous system (SNS)
Autonomic nervous system (ANS)
Enteric nervous system (ENS)
Somatic Nervous System Sensory neurons Convey info from
head, body wall, and limbs and from receptors for special senses (vision, hearing, taste smell) to CNS
Somatic Nervous System Motor neurons Conduct impulses from where to where
CNS to skeletal muscles
voluntary control
Autonomic nervous system Sensory neurons Convey information from receptors in the ___ to where
visceral organs (stomach and lungs)
to
CNS
Autonomic nervous system Motor neurons Conduct impulses from ____ to where
CNS
to
smooth muscles,
cardiac muscles, and glands (involuntary control)
Autonomic nervous system Motor neurons is subdivided into
Sympathetic: “fight or flight”
Parasympathetic: “rest and digest”
Enteric Nervous System “Brain of the gut” Sensory neurons Monitor _____, where
chemical changes in GI tract, stretching of
walls
Enteric Nervous System “Brain of the gut” Motor neurons Regulate what
contractions, acid secretion, endocrine cell
secretions
