PNS 1
What are at least three bodily functions that the Autonomic Nervous System oversees?
Involuntary responses: heart rate, breathing, blood vessel diameter, digestion, waste elimination, pupil dilation and constriction
What are the two types of cholinergic receptors? What is the effect on each type when ACh binds to them?
Nicotinic and Muscarinic; nicotinic receptors are excitatory, muscarinic receptors are excitatory or inhibitory
What is multiple sclerosis and how does it affect nerve signal transmission?
Autoimmune disorder where immune system attacks/degrades myelin, which slows down transmission speed of APs
At rest, where are the concentrations of K+, Na+, and Cl- highest (inside or outside the cell)?
K+: high inside
Na+: high outside
Cl-: high outside
How are graded potentials different from action potentials?
Graded potentials are short lived and local changes in membrane potential that dissipate over time and space. They summate at the axon hillock and can cause an AP
Action potentials are irreversible, all or nothing, traveling waves of electrical excitation down the axon
What are the names of the “fight or flight” and “rest and digest” systems? What specific functions do they control?
Sympathetic Nervous System: heart rate, blood pressure, skeletal muscle perfusion
Parasympathetic Nervous System: digestion, waste elimination, sexual arousal
Which system does methamphetamine stimulate? What symptoms does meth use cause?
SNS: Bruxism and hyposalivation
What are the 3 structural and 3 functional classifications of neurons?
Structural: Multipolar, Bipolar, Unipolar
Functional: Sensory (afferent), Motor (efferent), Interneurons
How many Na+ and K+ does the NA+/K+ pump move? Does each ion move in or out of the cell? What does this maintain inside the cell?
3 Na+ out, 2 K+ in
Resting membrane potential: -70mV
During each phase of an action potential (depolarization, repolarization, hyperpolarization) what ion channels are open? What direction are ions moving?
Depolarization: Na+ voltage gated channels open, Na+ rushes into cell (K+ votlage gated channels starting to open)
Repolarization: K+ voltage gated channels open, K+ rushes out of the cell (Na+ votlage gated channels are inactive, Na+ stops moving into the cell)
Hyperpolarization: K+ voltage gated channels are slowly closing, so a little extra K+ leaves the cell
What system innervates the adrenal medulla? What does it produce?
SNS; adrenaline (Epi and NE)
Give an example of an organ in the body that is not dually innervated. What part of the autonomic nervous system controls it? How is it's activity level regulated?
Blood vessels are only innervated by the SNS for vasoconstriction and vasodilation. The level of constriction/dilation is controlled by the frequency of action potentials the SNS sends
Define temporal and spatial summation
Temporal: graded potentials summated that were sent around the same time from the same presynaptic neuron
Spatial: graded potentials summated that were sent by different presynaptic neurons
Describe excitatory and inhibitory postsynaptic potentials. How do they differ?
Excitatory: depolarize cell with positive ions, around 30 EPSPs can cause an AP
Inhibitory: hyperpolarize cell with negative ions, brings membrane potential further from threshold
What would happen to membrane potential if K+ channels were unable to fully close during hyperpolarization? How would this affect following APs?
K+ would continue to leave the cell and membrane potential would become more negative, another action potential couldn't fire
Under normal conditions, what is the result of norepinephrine binding to a B1 adrenergic receptor? What is the result if a beta blocker binds to the receptor instead? What about a beta agonist?
NE: Increase heart contraction and heart rate
Beta blocker (antagonist): decrease heart rate
Agonist: increase heart rate
What is the effector of the somatic motor division? What are some effectors of the visceral motor division?
Somatic: skeletal muscle
Visceral: "Viscera", internal organs like the heart and lungs, smooth muscle, and glands
Name all 6 glial cells of the nervous system
What are their functions and are they in the CNS or PNS?
CNS: Ependymal cells (produce CSF), Microglia (macrophages), Astrocytes (regulate environment around neurons), Oligodendrocytes (form myelin sheaths)
PNS: Satellite cells (regulate environment around neurons), Schwann cells (form myelin sheaths)
What is a refractory period? When does each kind of refractory period occur during an action potential?
The part of an action potential when another action potential can't be fired
Absolute: Depolarization and repolarization. Absolutely no more action potentials can be fired
Relative: Hyperpolarization. Another action potential can fire if the stimulus is great enough
What is the difference between continuous and saltatory conduction of action potentials?
Continuous conduction: AP travels entire length of axon
Saltatory conduction: AP jumps from nodes of ranvier
Draw the sympathetic and parasympathetic pathways. Include preganglionic and postganglionic neurons with appropriate axon lengths, the neurotransmitters released by each neuron, and the receptor types they bind to
SNS: short pregang and long postgang axon, pre releases ACh and binds to nicotinic receptors, post releases adrenaline (binds to adrenergic receptors) or ACh (binds to muscarinic receptors)
PSNS: long pregang and short postgang axon, pre releases ACh and binds to nicotinic receptors, post releases ACh and binds to muscarinic receptors
What are the three pre-synaptic pathways that leave the thoracolumbar division? What are their target organs?
Spinal nerve pathway: innervates muscles and body wall
Sympathetic nerve pathway: innervates head and thoracic cavity
Splanchnic nerve pathway: liver, spleen, adrenal glands, stomach, intestines, kidneys urinary bladder, reproductive organs (abdominal cavity)
Draw a neuron and label the following: soma, dendrites, axon hillock, axon, axon terminals, myelin sheath, nodes of ranvier
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Draw an action potential and label the following: depolarization, repolarization, hyperpolarization, resting membrane potential, threshold
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What are two factors that influence the speed of an action potential?
Myelin, axon diameter
(Wide myelinated axons will transmit an action potential faster than thin unmyelinated axons)