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74 Cards in this Set
- Front
- Back
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DEPOLARIZATION
ABSOLUTE REFRACTORY PERIOD -70 signal -55 threshold +30 Action potential |
1. Recives end plate potential
2. Sarcolomma becomes permeable to sodium 3. Voltage gated channels open 4. Sodium diffuses rapidly into cell 5. Resting potential decreased (Inside becomes more positive)= DEPOLARIZATION 6. If stimulus reaches threshold action potential occurs |
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Action potential travels over the entire sarcolomma
Second step in Action Potential |
1. Positive charge resulting from open sodium channels
2. Membrane potential in that region decreases 3. Depolarization occurs in that region too |
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REPOLARIZATION
Electrical conditions restored +30 RELATIVE REFRACTORY PERIOD Third step in Action potential |
1. Depolarization wave passes
2. Sodium channels close 3. Potassium channels open 4. Potassium diffuses from cell 5. Internal negativity is restored |
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Refractory Period
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Cell cannot be stimulated again until repolarization is complete.Keeps us from unwanted repeated movements
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Resting Membrane Potential
-70 |
Called end plate potential
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-55
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Threshold
Strong enough signal Below -55 no action |
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Longitudinal Fissure
Transverse Fissure |
Separates the cerebral hemispheres
Seperates the cerebral hemishperes from the cerebellum |
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ATP Sodium/ Potassium Pump
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Restores ionic conditions of the resting state
3 sodiums pumped out 2 potassiums pumped out |
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ACh
Acetylcholine |
Causes ion channels to open
def: Neurotransmitter fx: Opens ion channels and initatating depolarization 1. Diffuses into synaptic cleft 2. Attaches to sarcolomma receptors 3. Open ion channels 4. Initiates depolarization |
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First step excitation-contraction coupling
Transmission/ transportation of action potential 1 |
1.Action potential propagates along sarcolomma
2. Goes down T-tubules |
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After action potential travels through the T tubule
Second step excitation- contratraction coupling 2 |
1. Action potential in T tubule activates voltage sensitive receptors and triggers Calcium release from the terminal cisternae of SR into cytosol
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Calcium binds to this
Third step excitation-contraction coupling 3 |
1.Calcium binds to troponin
2. Troponin changes shape 3. Removes the blocking action of tropomyosin 4. Actin active sites exposed |
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Myosin heads do this
Fourth step excitation-contraction coupling 4 |
Contraction
1. Myosin heads attach to actin 2. Myosin heads detach 3. Pull actin filaments toward the center of sarcomer 4. Release of ATP hydrolysis(Powers the stroke/cycling process) |
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Calcium pump does this
Fifth step excitation-contraction coupling 5 |
1. Action potential ends
2. Calcium removed ATP calcium pump 3. Calcium put back into the SR (Sarcoplasmic Reticulum)to be stored |
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Low levels of calcium that are needed to bind troponin make this occur
Sixth step excitation-contraction coupling 6 |
1. Tropomyosin blockage restored
2. Myosin blocked from binding on sites of actin 3. Contraction ends(crossbridge activity) 4. Muscle fiber relaxes |
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Tropomyosin
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Does this to myosin
Block myosin binding sites on actin so that the myosin heads cannot bind to actin. |
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Troponin
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Calcium binds to this
Calcium binds to troponin, which changes shape and removes the blockin action of tropomyosin. |
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Hyperpolarization
Keeps nerve impulses from probability (reaching threshold) Below -70 |
Membrane potential increases
Becomes more negative inside than in resting potential -70mV to -75mV Nerve impulses need to be stronger to reach threshold in hyperpolarization. |
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Central Nervous System
Interprets sensory input and dictates motor responses based on past experiences |
Composed of:
brain and spinal cord fx: integrating and command center of the nervous system |
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Brain Development
Starts in a 3 week embryo |
Surface ectoderm develops into
Nerual plate Neural folds Neural groove Neural crest Neural tube |
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Cerebrum
Lateral ventricles |
Formed from: Telencephalon
Make up: Cerebral Hemispheres which are: Cortex White matter basal nuclei |
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Diencephalon
Third ventricle |
Formed from: Diencephalon
Make up: Thalaumus Hypothalamus Epithalimus Retina |
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Brain Stem 1
Cerebral aqueduct |
Formed from: Mesencephalon
Midbrain |
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Brain Stem 2
Fourth ventricle |
Formed from: Mesencephalon
Pons |
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Brain Stem 3
Fourth ventricle |
Formed from: Mesencephalon
Medulla oblongata |
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Cerebral Cortex
CONSCIOUS MIND |
Part of the cerebral hemisphere
1.Enables us to be aware of ourselves and our sensations 2.Communicate 3.Remember 4.Understand 5.Initiate Voluntary Movements Composed of: gray matter, neuron cell bodies, dindrites, associated glia, blood vessels -NO fiber tracts |
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Diencephalon
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Formed from: Diencephalon
Make up: Thalaumus Hypothalamus Epithalimus Retina |
Third ventricle
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Primary Motor Cortex
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loc: posterior part of frontal lobes
Allows conscious control of precise, skilled, voluntary movement |
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Premotor Cortex
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Contorls learned, repititous, or patterned motor skills.
Planning of movement |
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Broca's area:
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Present in only one hemisphere(left)
Motor speech area: directs the muscles involved in speech production |
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Frontal eye field
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Gives us the ability to move the eyes.
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Somatosensory:
Somasensory Association Cortex |
Stimulus goes in
Integration(forming the comprehensive) |
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Prefrontal cortex:
Wernicke's Area: Left brain: Right brain: |
Personality (frontal labotomy)
Words you don't know language, math, logic Spacial skills, emotion, artistic skills |
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What is cerebral White Matter
MUST HAVE LINKS IN ORDER TO COMMUNICATE |
loc: deep to the cortical gray matter
contains: basal nuclei fx: responsible for communication between cerebral areas and 1. cerbral cortes 2. lower CNS centers 3. the rest of the brain |
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Basal Nuclei
sometimes called basal ganglia |
loc: deep within the cerebral white matter
contains: Caudate Putamen Globus pallidus corpus striatum fx: 1. Influence muscle movements directed by the primary motor cortex 2. Inhibit antagonistic or unnecessary movements Disorders: To much or too little movement Hunington's chorea and Parkinson's disease |
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Gyri plural
Gyrus singular |
Loc: top of cerebral hemishphere, top of cortex
def: elevated ridges of tissue (twisters) |
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Sulci plural
Sulci singular |
Loc: cerebral hemisphere
def: shallow grooves in brain several sulci divide each hemisphere into five lobes Divide the cerebral hemispheres into lobes |
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Central Sulcus
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Loc: frontal plane
fx: seperates the frontal lobe from the parietal lobe Divide frontal and parietal lobes |
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Parieto- Occipital Sulcus
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Loc: on the medial surface of the hemisphere
fx: seperates occipital lobe from parietal lobe Divide occipital and parietal lobes |
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Lateral Sulcus
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Loc:outlines the temporal lobe
fx: separates the parietal and temporal lobes contains: insula Deep sulcus divides parietal and temporal lobes |
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PNS
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Peripheral Nervous System
Paired spinal and cranial nerves fx: carries messages to and from the brain and spinal cord MESSENGER |
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Thalamus
DEEP WELL HIDDEN PROTECTED RECEIVES FIBER FROM THE CEREBRAL CORTEX |
COMMUNICATION CENTER
IT IS THE CENTER POINT Receives input and funnels it to the cerebral cortex. fx: key role in 1. mediating sensation 2. motor activities 3. corticol arousal 4. learning 5. memory |
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Hypothalamus
Connects to pituitary gland Stalk of hypolthalamus is called the infundibulum |
CONTROL CENTER (VISCERAL)
fx: main visceral control center in the body 1.maintains water balance 2.regulates thirst 3.eating behavior 4.gastrointestinal activity 5.body temperature 6.activity of the pituitary gland(secretion of hormones) and produce hormones ADH, Oxytocin 7. Sleep-Wake cycles(daylight,darkness clues) |
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Epithalamus
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SLEEP HORMONES AND MOOD
Pineal Gland Secretes melatonin |
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Anatomy of Cerebellum
Looks like a tree(arbor vitae) HAS RIDGES |
2 hemishpheres
3 lobes Anterior Posterior Floccunondul marked by convolutions seperated by vermis connected to brain stem by superior, middle, inferior peduncles |
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Fx of Cerebellum
Takes information tells us the best way to move PROTRUDES UNDER OCCIPITAL LOBES OF CEREBRAL HEMISPHERES |
COORDINATION OF MOVEMENT
SUBCONSCIOUSLY Processes Interprets impulses from: 1.motor cortex 2.sensory pathways 3.coordinates motor activity this means smooth, well timed movements 4. Cognition |
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Anatomy of Midbrain
Connects 3rd & 4th Ventricles |
Cranial Nerves III and IV
Between diencephalon and pons Surrounds the aqueduct Contains: 1.Corpura Quadrigemina(visual/auditory reflex centers) 2.Red nucleus (subcortical motor centers) 3.Substantia nigra High content of melanin pigment precursor to dopamine 4.periaqueductal grey matter (involved in pain supression) Controls two cranial nerves III and IV |
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Fx of Midbrain
Startle Reflex |
Superior colliculi- Visual reflex centers: coordinate head and eye movements when we visually follow a moving object
inferior colliculi: auditory relay from the hearing receptors of the ear to sensory cortex. Startle reflex occurs here |
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Pons
Anterior wall of 4th Ventricle |
CONDUCTION AREA
REGULATION OF RESPIRATION AND CRANIAL NERVES V-VI-VII Between midbrain and medulla oblongata Complete pathway between higher brain centers and spinal cord |
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Anatomy of Medulla Oblongata
4th Ventricle |
Most inferior part of brain stem.
Central canal of the spinal cord continues upward into the medulla. Desussation of the pyramids: Crossover causes voluntary movements of muscles on opposite side. Hypoglossal nerves Glossopharyngeal nerves Vagus nerves Vestibular nuclear complex: Maintain equilibrium Cochlear nuclei(auditory relay) |
Pyramids
Olives |
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Fx: Medulla Oblongata
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AUTONOMIC REFLEX CENTER
Cardiovascular center: Adjusts the force and rate of heart contraction to meet body needs Vasomotor Center: Changes blood vessel diameter Respiratory Centers: Control rate and depth of breathing/ Maintain respiratory rhythm Various other centers: Vomiting, hiccuping, swallowin, coughing, sneezing |
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Peripheral Nervous System
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loc: Outside the CNS
consists of: 1.Nerves(bundles of axons)that go from the brain and spinal cord 2 Spinal nerves: carry impulses to and from the spinal cord 3. Cranial nerves: carry impulses to and from the brain |
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PNS Sensory Afferent Division
Afferent: Carrying toward Keeps the CNS informed of events happening in and outside of the body |
consists of:
nerve fibers: convey impulses to the CNS sensory receptors:-convey impulses from the skin, muscles, joints called SOMATIC AFFERENT FIBERS transmit impulses from visceral organs VISCERAL AFFERENT FIBERS |
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PNS Motor Efferent Division
Efferent: Carrying away |
Carries impulses from CNS to effector organs (muscles/glands)
This impulse activate muscles to contract and glands to secret |
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Somatic Nervous System:
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Impulse from CNS to Voluntary nervous system (Skeletal muscles)
fx: control our skeletal muscles |
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Autonomic Nervous System: (ANS)
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Visceral motor nerve fibers that regulate the activity of involuntary nervous system (smooth musxles, cardiac muscles, glands)
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Parasympathetic
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Conserves energy
Promotes housekeeping functions during rest |
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Symathetic
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Mobilizes body systems during activity
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Supporting Cells
Anatomy of |
Neurologia: Also called glia cells(nerve glue)
Distinguished by:small cell size and darker staining nuclei Most have branching processes and a cell body fx: cells provide a supportive scaffolding for neurons. |
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Astrocyes (Star Cells)
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Most abundant of all glial cells.
Numerous radiating process. 1. Guiding the migration of young neorons 2.Control chemical environment by "Mopping up leaked potassium ions, recapturing/ recycling released neurotransmitters. |
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Microglia (Ovid cells)
Important becaus cells of the immune system are not able to acces the CNS |
Thorny processes
fx: Monitor health of neurons If finds invading microorganisms or dead neurons microglia transform into a macrophage and phagocytizes the debris. |
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Ependymal cells: Wrapping garment
Shape from squamos to columnar some are ciliated Protective Barrier |
fx: line the central cavities of the brain and the spinal cord.
Makes a permeable barrier between cerbrospinal fluid and tissue fluid Cilia helps to circulate the cerebrospinal fluid that cushions the brain and spinal cord |
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Oligondendrocytes
Wrap CNS nerve fibers/ Myelin Sheaths |
Not many processes
Wrap processes tightly around fibers, producing insulating coverings called Myelin Sheaths |
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Satellite Cells
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loc: surround neuron bodies in the PNS (ganglia)
fx: unknown |
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Schwann cells (neurolemmocytes)
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Surround and form myelin sheaths aroung the larger nerve fibers in the PNS
Vital to regeneration of damaged Peripheral nerve fibers |
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Neurons
structural units of the nervous system |
Highly specialized cells that conduct messages in the form of nerve impulses from one part of the body to another.
1. Extreme longevity (lifetime) 2. Amitotic- Do not divide they cannot be replaced 3. High metabolic rate - Always need oxygen and glucose -die within couple minutes w/out oxygen all have cell body and one or more processes. |
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Dendrites
fx: Main RECEPTIVE or INPUT region of neuron Electrical signals graded potentials- don't reach threshold Processes in CNS called Tracts Processes in PNS called Nerves |
Short, tapring, branching extensions.(Twiglike)Cluster close to the cell body
Has a large surface area RECEIVE SIGNALS FROM OTHER NEURONS |
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Axon
fx: CONDUCTING REGION generates nerve impulses and transmits them away form the cell body of neuron fx: secrete neurotransmittors NO NISSL BODIES OR GOLGI BODIES Some of these are very long. Lumbar region of spine to foot (3) meters long |
Every neuron has a single axon.
Axon arises from CONE shaped Axon Hillock- then becomes skinny. ANY LONG NEURON CALLED A NERVE FIBER Axons have OCCASIONAL branches along their length called AXON COLLATERALS AT THE END OF THE AXON |
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Myelin Sheath
Myelin sheath is surrounded and formed by Schwann cells in the LARGER neurons in the PNS |
White, fatty(protein, lipid) segmented.
1.Protects and electrically insulates fibers 2. Increases transmission of nerve impulses |
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Schwann cells
ONE INTERNODE= Nucleus and most of the cytoplasm end up as a bulge just external to the myelin sheath |
NEURILIMMA= Sheath of Schwann. Surround and form myelin sheaths around the larger nerve fibers in the PNS
Tightly coiled wrapped membranes. Schwann cells do NOT touch |
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Nodes of Ranier (Neurofibril Nodes)
CURRENT(action potential) CAN ONLY PASS THROUGH THE MEMBRANE OF A MYELINATED SHEATH HERE!!! |
def: Gaps between Schwann cells along an axon.
Occur at regular intervals along the myelinated axon- the current jumps from node to node. Widely spaced in the CNS |
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Multipolar Neuron Type
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Many processes all dendrites 1 single axon
Receptive region Chemicaly gated ion channels Interneurons and Motor neurons |
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Bipolar Neuron Type
Sensory neurons |
Two processes
one process on dendrite one on axon Conducting region(generates/transmits) action potential Voltage gated Sodium and Potassium channels Rare. special sensory organs (olfactory mucosa, eye, ear) |
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Unipolar(psuedopolar)
Sensory neurons Send to afferent pathways to the CNS for interpretation |
One process from the cell body forms central and peripheal processes which together comprise an axon
Seretory region (release neurotransmittors) PNS Common in dorsal root ganglia, sensory ganglia of cranial nerves |
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