Exam 2- Nervous, Endocrine, Cardio, Respiratory Systems Flashcards
What are the 3 main functions of the NS?
1) sensory input
2) integration
3) motor output
What does the CNS consist of?
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Brain and spinal cord
What does the PNS consist of?
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12 pairs of cranial nerves and 31 pairs of spinal nerves
What is a part of the autonomic NS?
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Sympathetic (fight/flight) and parasympathetic (rest/digest)
What are the cells of the nervous system?
-glia or neuralgia
-neurons
What is the function of neuroglia
Provide metabolic support and mechanical scaffolding of neurons
What are the 3 ways to organize the NS?
Structure, function, and direction of flow
What are the structural classifications of NS?
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CNS and PNS
What are the functional classifications of NS?
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Somatic and autonomic NS
What are the direction of flow classifications for the NS?
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Afferent and efferent
What types of neuroglia are found in the CNS?
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1) oligodendrocytes
2) astrocytes
3) microglia
4) ependymal cells
What is the fight or flight division of NS?
Sympathetic NS
What is the rest and digest division of NS?
Parasympathetic NS
What are oligodendrocytes? What is the function of oligodendrocytes?
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Type of neuroglia in CNS
Produce the myelin sheath around nerve fibers in the CNS
What are astrocytes? What are the functions?
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A type of neuroglia in CNS
-maintain BBB
-attached to brain capillaries
-biochemical support for CNS tissue regulation of blood flow and movement of substances to/from blood to nervous tissue
What are microglia? What is the function?
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A type of neuroglia in the CNS
resident macrophage cells of CNS (main form of active immune defense)
What are ependymal cells? What are the functions?
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A type of neuroglia in the CNS
-lines ventricular system of the brain and spinal cord
-produces CSF
What are the neuroglia of the PNS?
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Schwann cells and satellite cells
What are Schwann cells? What do they do?
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-neuroglia of the PNS
-also called neurolemmocytes
-produce myelin sheath around nerve fibers in the PNS
What are satellite cells? What do they do?
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-neuroglia of the PNS
-cover the surface of nerve cell bodies in the PNS
-regulate neuron environment
What are the functions of myelin sheath?
-increase speed of electrochemical impulse transmission
-insulate and protect axon or nerve fiber
What is the neurilemma?
Outer layer of neuroglia cell cytoplasm surrounding an axon
What is the node of ranvier?
-gaps in the myelin sheath between adjacent glial cells
-axon is exposed to ECF (sodium influx)
What are the 4 neuronal zones?
1) Input zone
2) summation zone
3) conduction zone
4) output zone
What is a part of the input zone?
Dendrites and cell bodies
Dendrites process/carries impulses to the soma
Cell body/soma contains the nucleus
What is a part of the summation zone of the neuron?
Axon hillock (adds EPSPs and IPSPs)
What is a part of the conduction zone of the neuron?
Axon and collateral axons
Axons process/carries impulses away from the soma
Collateral axons are the side branches of axons
What is a part of the output zone of the neuron?
Telodendria and axon terminals
Telodendria are the distal branches of the main axon
Axon terminals, also called synaptic terminals or terminal buttons are expanded tips of the telodendria
What are the two ways to classify neurons?
Structural (number of processes from the soma) and functional (direction impulse relative to CNS)
What is the structural classification of neurons?
Number of processes from the soma
What is the functional classification of neurons?
Direction impulse relative to CNS
What are the 3 types of neurons under the structural classification?
1) pseudo-unipolar (1 process that divides like a “T”)
2) bipolar (2 processes (1axon + 1 dendrite))
3) multipolar (2+ processes (1 axon+ 2+ dendrites))
What does a pseudo-unipolar neuron look like?
1 process that divides like a T
ex: DRG
Is a pseudo-unipolar neuron a sensory or motor neuron?
sensory neuron
What does a bipolar neuron look like?
2 processes (1 axon + 1 dendrite)
ex: found in the retina and olfactory mucosa
Is a bipolar neuron a sensory or motor neuron?
sensory neuron
Which structural neuron is the rarest type?
bipolar neuron
What does a multipolar neuron look like?
more than 2 processes (1 axon and 2+ dendrites)
ex: found in the nervous system
What are the functional classifications of a neuron?
-afferent (sensory)
-interneurons (association)
-efferent (motor)
Are afferent neurons sensory or motor neurons?
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sensory neurons
Are efferent neurons sensory or motor neurons?
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motor neurons
Which neurons send impulses toward the CNS?
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afferent (sensory) neurons
Which neurons are usually pseudo-unipolar?
afferent (sensory) neurons
Which neurons have the cell bodies located in the ganglia outside of the CNS?
afferent (sensory) neurons
Which neurons are known as the association neurons?
interneurons
Which neurons connect the sensory and motor neurons?
interneurons
Which neurons are usually multipolar and located inside of the CNS reflex arc?
interneurons
Which neurons are motor neurons and send impulses away from the CNS?
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efferent neurons
Which neurons are usually multipolar and the cell bodies are located inside the CNS?
efferent neurons
define upper motor neuron (UMN)
neuron that starts in the motor cortex of the brain and terminates within the medulla or within the spinal cord
define lower motor neuron (LMN)
nerve cell that goes from the spinal cord to a muscle
What is an electromotive force?
difference in potential that tends to give rise to an electric current
it exists by virtues of separation of opposite charges
What are membrane potentials?
a cell membrane potential is the electromotive force that exits across the plasma membrane
What are the 3 types of membrane potentials?
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-resting membrane potential
-local (graded) potential
-action potential
What is a resting membrane potential?
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electromotive force that exists across the plasma membrane when a cell is at rest
What is a local/graded potential?
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a slight shift away from resting membrane potential in a specific/local region of the cell membrane
Note: there are 2 types: EPSP and IPSP
What are the 2 types of local/graded potentials?
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1) EPSP (excitatory post synaptic potential, the inside of the cell membrane comes closer to threshold potential (less negative or more positive))
2) IPSP (inhibitory post synaptic potential, inside of the cell membrane moves further from the threshold potential (more negative))
What is a threshold potential?
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summation of graded/local potentials that reaches a certain critical magnitude at the axon hillock to generate an action potential
What is an action potential?
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change in electrical potential associated with the passage of an impulse along the cell membrane (at this point, axonal depolarization is self-generating and non-decremental)
What are the 5 phases of an action potential?
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1) resting phase (all Na+ and K+ voltage gated channels are closed)
2) depolarization phase (threshold potential reached, Na+ voltage gated channels open)
3) repolarization phase (Na+ voltage gated channels close, and K+ voltage gated channels open)
4) Hyperpolarization phase (brief delay of K+ voltage gated channels close)
5) return to rest (all Na+ and K+ channels are closed, Na+/K+ pump restores resting membrane potential)
What is a synapse?
a junction/minute gap across which a nerve impulse passes from an axon terminal to a neuron, muscle cell, or gland cell
What are the 2 classifications of synapses?
structural and functional classes
What are the structural classifications of synapses?
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-neuronal (between neurons)
-neuromuscular (between neuron and muscle)
-neuroglandular (between neuron and gland)
What are the 2 functional classes of synapses?
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electrical and chemical
What are the 3 components of all synapses?
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-presynaptic neuron (axon terminal/synaptic knob)
-synapse (synaptic cleft)
-postsynaptic cell (plasma membrane)
What are the 3 major events of chemical/neurotransmitters synaptic transmission?
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1) presynaptic event
2) synaptic event
3) post synaptic event
What are the presynaptic events of chemical/neurotransmitter synaptic transmission?
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-AP arrives at the axon terminal of the presynaptic neuron
-calcium voltage gated channels open in axon terminal plasma membrane and calcium enters
-cytoskeleton contracts to release neurotransmitter vesicles into synapse
What are the synaptic events of the chemical/neurotransmitter synaptic transmission?
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neurotransmitter diffuses across interstitial fluid of the synaptic cleft
What are the postsynaptic events of the chemical/neurotransmitter synaptic transmission?
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-neurotransmitter binds to protein receptors on postsynaptic plasma membrane
-open or close chemical ligand gated ion channels
-EPSP or IPSP created on postsynaptic plasma membrane
Neurotransmitter is a substance that is released from the axon terminal of a _____________ neuron upon excitation, and that travels across the synaptic cleft to change membrane potential (either excite or inhibit) of the target cell (nerve, muscle, organ, or other tissue)
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presynaptic
What are some examples of small molecule neurotransmitters?
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-ACh
-dopamine
-Epi
-NE
-serotonin
-GABA and glycine
-glutamate
Where is ACh found?
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in the motor and parasympathetic pathway (at the synapse with the target organ)
What is the function of dopamine?
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motor and cognitive motivation
What is the function of Epi?
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attention
Where is NE found?
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in the sympathetic pathway (at the synapse with the target organ)
What is the function of serotonin?
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arousal, emotions, mood, and sexual urges
What is the difference between GABA and glycine in terms of location?
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GABA is found in the brain, where as glycine is found within spinal column (both are small neurotransmitters)
What is the function of GABA and glycine?
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inhibit CNS (brain for GABA, spinal cord for glycine)
Which neurotransmitter excites the CNS?
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glutamate
What are the 2 large molecule neurotransmitters?
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endorphins and enkephalins
What is an endorphin? How are enkephalins related?
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endorphins= hormone secreted within the brain and nervous system that binds to the body’s opiate receptors, causing an analgesic/pain relieving effect
enkephalin= peptide, not hormone, but has the same pain relieving effect
What is an axon?
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neuron fiber
What word describes a bundle of nerve fibers?
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fascicle
What words describes a bundle of fascicles in PNS?
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nerve
What surrounds a nerve fiber?
endometrium
What surrounds a fasiscle?
perineurium
What surrounds nerves?
epineurium
What nerves consist of both efferent and afferent neurons?
mixed neurons
What are the 3 types of nerves?
1) afferent (sensory, impulses toward CNS)
2) efferent (motor, impulses from CNS)
3) mixed nerves (both efferent and afferent)
What are fissures?
deep grooves
What are notches?
indentations
What are sulci?
shallow grooves
What are gyri?
elevations, folds, convolutions
precentral gyrus = ___________ cortex
motor
postcentral gyrus = ________________ cortex
somatosensory
What are the 5 structural lobes of the brain?
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1) frontal
2) parietal
3) temporal
4) occipital
5) insular
Brain lobes are named after the cranial bones they connect with, besides the….
insular lobe
What is the prosencephalon?
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forebrain
What are the 2 parts of the prosencephalon (forebrain)?
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1) telencephalon (cerebral hemispheres, right and left)
2) diencephalon (inner brain)
What are the 3 parts of the diencephalon (inner brain)?
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1) epithalamus (pineal gland makes melatonin)
2) thalamus (gateway to the cerebral cortex, “switchboard”)
3) hypothalamus (pituitary gland)
What are the 2 parts of the brainstem?
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1) mesencephalon (midbrain is in charge of visual, auditory, and motor)
2) rhombencephalon (hindbrain)
What are the functions of the mesencephalon (midbrain)?
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visual, auditory, and motor
What are the 2 parts of the rhombencephalon (hindbrain)?
1) metencephalon (after brain)
2) myelencephalon (spinal brain/ medulla oblongata)
What are the 2 parts of the metencephalon?
1) pons
2) cerebellum
Who produces neurotransmitters?
pons
Who is in charge of coordination and balance?
cerebellum
What is the function of the myelencephalon/medulla oblongata?
its the cardio and respiratory center
What are meninges?
layers of connective tissue which surrounds and protects the CNS
What are the 2 layers of the dura matter?
1) periosteal (endosteal) layer
2) meningeal layer (subdural space is below here)
What space is below the arachnoid mater? Is it a true space or potential space?
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subarachnoid space, its a true space containing most CSF
Which meningeal layer is in direct contact with the brain and spinal cord?
pia mater
What are the bran cavities of the ventral system of the brain?
-lateral right and left
-3rd ventricle
4th ventricle
The ventricular system of the brain is filled with CSF originating from the ____________________, capillaries in ventricles
chorioid plexus
Where does CSF leave through to enter the subarachnoid space?
4th ventricle
CSF is returned to….
dural venous sinuses
What are dural venous sinuses?
endothelium lined venous channels between the endosteal and meningeal layers of the dura mater
CSF is returned here
What is the circle of willis and where is it found?
pentagon shaped circle of arterial vessels on the ventral aspect of the brain in the area encircling the optic chiasm and pituitary gland
Who are the primary suppliers of oxygenated blood to the brain and contribute to the cerebral arterial circle/ circle of willis?
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internal carotid a. and vertebral aa.
The R and L vertebral arteries unite to form the ___________ artery, which is the terminal branch of the cerebral arterial circle/circle of willis
basilar
What is the epidural space?
space between the bony vertebrae and dura mater, filled w/ fat and has a network of veins
What does the central canal contain and how long is it?
contains CSF, runs the length of the spinal cord through the gray commissure
How many spinal cord segments are there?
31
8C, 12T, 5L, 5S, 1Cc
What is the cauda equinae?
spinal nerves emerging from inferior end of the spinal cord superior to conus medullaris and extending through to inferior end of spinal canal (L5-Cc1)
What is the conus medullaris and where is it found?
cone shaped terminus of the spinal cord at the level of L1 or L2 vertebrae (S1-Cc1)