Term
| what are the two divisons of the PNS? |
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Definition
Autonomic nervous system (ANS)
• Involuntary branch of PNS
• Innervates cardiac muscle, smooth muscle, most
exocrine glands, some endocrine glands, and adipose
tissue
– Somatic nervous system
• Subject to voluntary control
• Innervates skeletal muscle |
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Term
| give me as many differences as you can between the autonomic and somatic divisions of the PNS |
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Definition
ANS orginates in the brain or spinal cord, while SNS orginiates mostly in the spinal cord, but those supplying muscles in the head orginiate in the brain.
ANS has two neuron chains, while SNS has single neuron chains.
ANS innervates cardiac muscle, smooth muscle, exocrine and some endocrine glands, while SNS innervates only skeletal muscle
ANS effector organs are dually innervated by antagonistic brnaches of the ANS, while SNS organs are only innervated by motor neurons
ANS can use acetylcholine (parasymp) or norepinephrine (symp). SNS only uses acetylcholine
ANS can stimulate OR inhibit its effector organs, while SNS can only stimulate
ANS is involuntary, SNS is voluntary
ANS has the spinal cord, medulla, mypothalamus, and prefrontal association cortexes involved, while the SNS has the spinal cord, motor cortex, basal nuclei, cerebellum, and brain stem involved |
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Term
| how does the somatic nervous system work, in general?? |
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Definition
Axons of MNs originate in SC or BS- end on skeletal
muscle
• MN terminal releases ACh, stimulates muscle
contraction
• MNs are final common pathway
– All motor commands act through MNs to allow movement
– Controlled by multiple areas (SC, BS, sensorimotor cortex,
basal ganglia/cerebellum) |
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Term
| how does a motor neuron transmit to a muscle? |
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Definition
AP initiation/propagation from MN
down axon
• Neuromuscular junction
– Muscle fiber, terminal button (“motor
end plate”)
– Ach release
• Presynaptic vesicular
• Postsynaptic intracellular
– Endplate potentials
• nicotinic receptors (Na/K flow)
• Inflow of sodium and potassium
• AP propagated along muscle
fiber
– Ach breakdown – Ach esterase |
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Term
| how does the autonomic nervous system work, in general? |
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Definition
Autonomic nerve pathway
– Extends from CNS to an innervated organ
• Ganglion = neuronal cell bodies in the PNS
• Nuclei = neuronal cell bodies in the PNS CNS
– Two-neuron chain
• Preganglionic fiber (synapses with cell body of second neuron)
• Postganglionic fiber (innervates effector organ |
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Term
| what is the pregangliaonic neurotransmitter and receptor? what about postganglionic? |
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Definition
pre - Ach and nicotinic (ionotropic)
post - it could be any neurotransmitter, but its almost always a metabotropic response. |
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Term
| what are the two divisions of the the autonomic nervous system? |
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Definition
Symp NS (Thor, Lumb)
– Para NS (Cranial, sacral) |
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Term
| what are some differences between the sympathetic and parasympathetic nervous systems? |
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Definition
Sympathetic Nervous System Fibers originate in thoracic and lumbar regions of spinal cord. Most preganglionic fibers are short. Long postganglionic fibers. Preganglionic fibers release acetylcholine (Ach) Most postganglionic fibers release noradrenaline (norepinephrine)
Parasympathetic Nervous System Fibers originate from
cranial and sacral areas of CNS. Preganglionic fibers are
longer. Very short postganglionic fibers. Preganglionic fibers release acetylcholine (Ach). Postganglionic fibers release acetylcholine |
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Term
| what are some exceptions to the general innervations of the parasymp and symp nervous systems? |
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Definition
most arterioles and veins
receive only sympathetic
– Sweat glands only
sympathetic
– Salivary glands -both ANS
divisions, both stimulate
salivary secreti |
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Term
| what are some effects of sympathetic stimulation on various organs? (give 3 examples) |
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Definition
heart - increased rate, increased force of contraction
blood vessels - constriction
lungs - dilation of airways, inhibition of mucus secreation -
digestive tract - decreased movement, contraction of sphincters, inhibition of secretions
bladder - relaxation
eye - dilation of pupil
liver - glycogenolysis
fat cells - lipolysis |
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Term
| what are some effects of parasympathetic stimulation on various organs? (give 3 examples) |
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Definition
heart - decreased rate, decreased force of contraction
blood vessels - dilation of vessels of the penis or clitoris only
lungs - constriction of bronchioles, stimulation of mucus secretion
digestive tract - increased movement, relaxation of sphincters, stimulation of secretions
bladder - contraction (emptying)
eye - contraction of pupil
liver - none
fat cells - none |
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Term
| what is the adrenal medulla? |
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Definition
an endocrine gland on top of the kidney. Adrenal medulla is a
modified symp nervous
system
– Minimal postganglionic
fibers
– Preganglionic fiber
initiates hormonal
secretion
• 20% norepinephrine
• 80% epinephrine
(adrenaline)
• Broadcast vs.
localized |
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Term
| what are alpha and beta receptors? adrenergic? |
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Definition
Alpha (α) receptors -1
- vessel constriction, contraction of smooth muscle,
2
- relaxation in the digestive tract, inhibitory?
• Beta (β) receptors
- Found in the heart, increases contractility and rate
- Found in the arterioles and airways, dilator |
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Term
| muscoritic receptors are what? |
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Definition
| a type of cholinergic receptor found on effector cell membranes, use the g-protein system (metabotropic) |
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Term
| so for parasymp and symp, what is the length of the pre-ganglionic and post ganglionic neurons? |
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Definition
| symp preganglionic fibers are short, while parasymp preganglionic fibers are longer |
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Term
| what are the different autonomic neurotransmitter receptors? |
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Definition
Mostly modulatory (effector organ)
– Localized – varicosities, broadcast – adrenal medulla
– Cholinergic receptors – bind to ACh
• Nicotinic receptors – cell bodies of autonomic ganglia
• Muscarinic receptors – found on effector cell membranes
– Adrenergic receptors – bind to norepinephrine and
epinephrine
• Alpha (α) receptors -1
- vessel constriction, contraction of smooth muscle,
2
- relaxation in the digestive tract, inhibitory?
• Beta (β) receptors
- Found in the heart, increases contractility and rate
- Found in the arterioles and airways, dilator |
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Term
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Definition
| basically a nerve has a bunch of bulbs along its axon that can secrete neurotransmitters, so it can elicit a response from a large part of an effector organ |
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Term
| how do beta 1 receptors work in the heart? |
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Definition
| they allow more calcium entry |
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Term
| how is the prefental association complex involved in the ANS? |
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Definition
emotional expression
characteristic of individual’s personality |
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Term
| how is the hypothatlamus involved in the ANS? |
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Definition
integrating autonomic, somatic, and endocrine responses
accompanying emotional and behavioral states |
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Term
| how is the medulla involved in the ANS? |
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Definition
| directly responsible for autonomic outpu |
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Term
| how is the autonomic reflexes involved in the ANS? |
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Definition
ALL autonomic reflexes, such as urination, defecation,
and erection, are integrated at spinal cord leve |
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Term
| what is the difference between visceral afferent and sensory afferent systems? |
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Definition
Visceral afferent- pathway from internal viscera
• Sensory afferent
– Somatic (body sense) sensation
» Sensation arising from body surface and
proprioception (limb/joint position, vestibular system)
– Special senses
» Vision, hearing, taste, smell |
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Term
| what are the 4 steps of a sensory response? |
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Definition
Transduction
• Transmission
• Modulation
• Perception |
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Term
| what are some Afferent nervous system receptors? |
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Definition
Types
– Photoreceptors - visible wavelengths of light
– Mechanoreceptors - mechanical energy/distortion
– Thermoreceptors - heat and cold
– Osmoreceptors – concentration of solutes in fluid
– Chemoreceptors - sensitive to specific chemicals
• smell and taste
•O2and CO2concentrations in blood
• chemical content of digestive tract
– Nociceptors - pain receptors |
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Term
| how does a stretch perception work in a muscle? |
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Definition
| spindles detect change in length and speed of change, golgi tendon organs detect change in force |
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Term
| how do receptor potentials work? |
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Definition
Afferent signaling (separate organ or afferent ending)
• Stimulus alters permeability = graded receptor potential
(positive ion flow – Na+)
• Magnitude of receptor potential = stimulus intensity
• AP propagated along afferent neuron to CNS |
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Term
| what is receptor adaptation? |
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Definition
| receptors may adapt slowly or rapidly to sustained stimulation. |
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Term
| with regards to receptor adaptation, what is a tonic receptor vs a phasic receptor |
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Definition
Tonic receptors – slow adaptation– muscle/joint receptors
– Phasic receptors – rapid adaptation – tactile cutaneous |
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Term
| what are the orders of chains of neurons interconnected for sensory processing? |
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Definition
First-order - Afferent with peripheral receptor (detects stimulus)(goes to second order)
– Second-order- SC or medulla (goes to 3rd order)
– Third-order – located in thalamus (goes to cortex) |
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Term
| what are the two pathways of somatosensory nerve receptions?? |
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Definition
Anterior spinothalamic tracts (pain, temp, gross touch)
– Dorsal columns (light touch, proprioception) |
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Term
| what is a 1st order neuron, and what are the types? |
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Definition
1st order neurons determine pathways (mostly), very in PNS
with fiber size and extent of myelination
these all decrease in size (and therefore speed of transmission) from type I - IV
–A– very fast (muscle stretch/spindle, tension/Golgi tendon organ
–A– most non-noxious cutaneous, joint, muscle length/spindle
–A– mildly noxious cutaneous, joint, muscle (pretty myelinated)
– C (IV) – small, unmyelinated, slow, prolonged noxious input (all areas) |
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Term
| A-gamma and B fibers, what are they? |
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Definition
| a-gammas are efferent, and B's are also efferent |
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Term
| what is largely responsible for type c fiber dull pain? |
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Definition
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Term
| what are the dorsal column pathways? |
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Definition
| they do light touch and proprioception |
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Term
| what is the 2nd order tract where you get decussation (crossing over) to the other side of the brain. |
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Definition
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Term
| what is the spinaothalamic pathway? |
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Definition
| gross touch, pain and temp. the crossing over (decussation) happens between the 1st and 2nd order neurons. |
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Term
| make cards for the STIMULUS PROPERTY - MECHANISM OF CODING slide |
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Definition
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Term
| what is acuity/localization? |
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Definition
Refers to discriminative ability
• Influenced by receptive field
size and lateral inhibition.
interneurons cause lateral inhibition. happens with fine touch and fine vision. |
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Term
| what are the three categories of pain receptors? |
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Definition
Three categories
– Mechanical nociceptors
– Thermal nociceptors
– Polymodal nociceptors |
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Term
| what is the difference between fast pain and slow pain? |
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Definition
Fast Pain Occurs on stimulation of mechanical and thermal nociceptors. Carried by small, myelinated Adelta fibers. Produces sharp, prickling sensation. Easily localized. Occurs first.
Slow pain - Occurs on stimulation of polymodal nociceptors. Carried by small, unmyelinated
C fibers. Produces dull, aching, burning sensation. Poorly localized. Occurs second, persists for longer time, more unpleasant |
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Term
| can pain pathways can be "learned" or have long term potentiation. |
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Definition
| yes! they can be hypersensitized or a non pain stimulus can be crossed over with the pain pathway |
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