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Questions and Answers
What effect do inhibitory neurotransmitters have on membrane potential?
What effect do inhibitory neurotransmitters have on membrane potential?
How do sedatives affect inhibitory postsynaptic potentials (IPSPs)?
How do sedatives affect inhibitory postsynaptic potentials (IPSPs)?
Which ions contribute to the depolarization of action potentials?
Which ions contribute to the depolarization of action potentials?
What is the relationship between frequency and stimulus strength?
What is the relationship between frequency and stimulus strength?
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What is the effect of illegal drugs like cocaine on dopamine in neuron synapses?
What is the effect of illegal drugs like cocaine on dopamine in neuron synapses?
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Which type of receptors in the human eye is primarily responsible for color vision?
Which type of receptors in the human eye is primarily responsible for color vision?
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Which sensory receptor is primarily responsible for detecting changes in temperature?
Which sensory receptor is primarily responsible for detecting changes in temperature?
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What role does vitamin A play in the function of photoreceptors?
What role does vitamin A play in the function of photoreceptors?
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What role does capsaicin play in sensory perception?
What role does capsaicin play in sensory perception?
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How does the frequency of action potentials relate to the perceived temperature?
How does the frequency of action potentials relate to the perceived temperature?
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What happens to sodium channels in the presence of light?
What happens to sodium channels in the presence of light?
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What is the function of phosphodiesterase (PDE) in the visual process?
What is the function of phosphodiesterase (PDE) in the visual process?
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Which ions are involved in the generation of inhibitory postsynaptic potentials (IPSPs)?
Which ions are involved in the generation of inhibitory postsynaptic potentials (IPSPs)?
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What initial event occurs when rhodopsin absorbs a photon?
What initial event occurs when rhodopsin absorbs a photon?
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Which component is considered a prosthetic group in the visual phototransduction process?
Which component is considered a prosthetic group in the visual phototransduction process?
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What is the primary function of the rods in the retina?
What is the primary function of the rods in the retina?
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What does the anterior pituitary store?
What does the anterior pituitary store?
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Which hormones are secreted by the thyroid gland to regulate metabolism?
Which hormones are secreted by the thyroid gland to regulate metabolism?
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What is the effect of increased levels of T3 and T4 in the body?
What is the effect of increased levels of T3 and T4 in the body?
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What role does calcitonin play in the body?
What role does calcitonin play in the body?
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How does the hypothalamus regulate the release of thyrotropin releasing hormone (TRH)?
How does the hypothalamus regulate the release of thyrotropin releasing hormone (TRH)?
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What initiates the release of thyroid stimulating hormone (TSH) from the anterior pituitary?
What initiates the release of thyroid stimulating hormone (TSH) from the anterior pituitary?
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What is the primary effect of parathyroid hormone (PTH)?
What is the primary effect of parathyroid hormone (PTH)?
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What could be a consequence of a hyperactive thyroid gland?
What could be a consequence of a hyperactive thyroid gland?
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What type of hormones can pass through cell membranes and enter all cells?
What type of hormones can pass through cell membranes and enter all cells?
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Which statement accurately describes the action of water soluble hormones?
Which statement accurately describes the action of water soluble hormones?
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What is a likely consequence when lipid soluble hormones bind to their receptors?
What is a likely consequence when lipid soluble hormones bind to their receptors?
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What is the role of the G protein in the mechanism of water soluble hormones?
What is the role of the G protein in the mechanism of water soluble hormones?
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What do all lipid soluble hormones require to exert their effects?
What do all lipid soluble hormones require to exert their effects?
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What triggers the initiation of an action potential in muscle cells?
What triggers the initiation of an action potential in muscle cells?
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Which of the following molecules serves as a second messenger in the signaling pathway activated by certain hormones?
Which of the following molecules serves as a second messenger in the signaling pathway activated by certain hormones?
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What initiates the signal transduction process for water soluble hormones?
What initiates the signal transduction process for water soluble hormones?
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What role does the sarcoplasmic reticulum play in muscle contraction?
What role does the sarcoplasmic reticulum play in muscle contraction?
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Which of the following describes the effect of Myasthenia Gravis on muscle function?
Which of the following describes the effect of Myasthenia Gravis on muscle function?
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How do lipid soluble hormones typically affect cellular functions?
How do lipid soluble hormones typically affect cellular functions?
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What is the primary effect of Lambert Eaton syndrome on neurotransmission?
What is the primary effect of Lambert Eaton syndrome on neurotransmission?
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How does tetanus affect muscle contraction?
How does tetanus affect muscle contraction?
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What is the result of calcium-induced calcium release in muscle contraction?
What is the result of calcium-induced calcium release in muscle contraction?
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What structural feature allows action potentials to propagate within muscle fibers effectively?
What structural feature allows action potentials to propagate within muscle fibers effectively?
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Which of the following disorders is characterized by the degeneration of motor neurons?
Which of the following disorders is characterized by the degeneration of motor neurons?
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What is the role of Botox in the context of muscle contraction?
What is the role of Botox in the context of muscle contraction?
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What distinguishes skeletal muscle contraction from smooth muscle contraction?
What distinguishes skeletal muscle contraction from smooth muscle contraction?
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What is the primary function of macrophages in the immune system?
What is the primary function of macrophages in the immune system?
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Which type of immunity is characterized by the production of antibodies by B-cells?
Which type of immunity is characterized by the production of antibodies by B-cells?
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What triggers the activation of a B-cell?
What triggers the activation of a B-cell?
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Which type of T-cell is responsible for recognizing and destroying infected cells?
Which type of T-cell is responsible for recognizing and destroying infected cells?
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What role do antibodies play in the immune response?
What role do antibodies play in the immune response?
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Which statement about immature B-cells is true?
Which statement about immature B-cells is true?
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What is the result of a B-cell's activation after antigen binding?
What is the result of a B-cell's activation after antigen binding?
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What is a unique feature of T-cells compared to B-cells?
What is a unique feature of T-cells compared to B-cells?
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Study Notes
Nervous System I
- There are approximately 100 billion neurons in the human brain.
- Neurons have a cell body (soma), dendrites, axon, axon hillock, myelin sheath, nodes of Ranvier, and synaptic end bulbs.
- Nerve tissue function involves axons as electrical conductors carrying signals from the axon hillock to presynaptic terminals.
- Potential in neurons involves signals traveling through dendrites, summing in the axon hillock, and transmitting down the axon to synapses.
- Glial cells (oligodendrocytes and Schwann cells) provide electrical insulation like the myelin sheath.
- The cell body contains the nucleus and other organelles.
- Bioelectricity in neurons is a voltage (~-70mV) generated by an ATP-consuming pump in the plasma membrane, creating an ion gradient.
- The sodium-potassium pump uses ATP to pump 3 sodium ions out and 2 potassium ions in.
- The inside of the cell is negatively charged.
- Ion gradients are crucial for nerve function; different ions have specific concentrations inside and outside the axon.
Nerve Tissue Function & Organization
- Neurons carry electrical signals, and these signals add up in the axon hillock, triggering an action potential.
- Signals transmit down the axon and across synapses to other neurons.
Potential (Bioelectricity)
- Neurons have a resting potential of -70mV (though it can range between -40mV and -70mV).
- The inside of the neuron is more negative than the outside due to unequal ion distribution.
- The sodium-potassium pump maintains these gradients.
- The resting potential is maintained by the membrane being impermeable to sodium and permeable to potassium.
- Potassium leaking out makes the inside more negative, counteracting the sodium influx.
- Equilibrium potential (EK+) describes the voltage at which the chemical and electrical forces on potassium are equal.
- The EK+ is approximately -85mV for a 30-fold gradient, and -58mV for a 10-fold gradient.
- Ion concentrations create gradients: extracellular fluid contains high sodium and chlorine, and the cytoplasm has high potassium concentrations.
Action Potential
- Action potentials begin at the axon hillock when the membrane suddenly becomes permeable to sodium ions.
- This depolarization causes further sodium channels to open, leading to a rapid increase in positive charge inside the neuron (reaching up to +50mV).
- Influx of sodium is followed by repolarization as potassium channels open slowly, allowing potassium to flow out of the neuron, restoring the negative resting potential.
- Sodium channels become inactivated, preventing the action potential from reversing direction.
- Action potentials propagate unidirectionally along the axon, jumping between nodes of Ranvier through saltatory conduction.
Propagation (Saltatory Conduction)
- Myelin sheaths insulate the axon causing faster signal transmission.
- Signals jump between nodes of Ranvier; which are rich in voltage-gated sodium channels.
Synaptic Transmission
- Chemical synapses use neurotransmitters to transmit signals across the synaptic cleft to another neuron.
- Neurotransmitters are stored in vesicles at the presynaptic terminal.
- Action potentials trigger calcium influx, leading to vesicle fusion and neurotransmitter release into the synaptic cleft.
- Neurotransmitters bind to receptors on the postsynaptic membrane (often ion channels).
- Neurotransmitters are removed from the synaptic cleft either by degradation or reuptake.
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Description
This quiz explores the fundamental aspects of the human nervous system, focusing on the structure and function of neurons and glial cells. It covers the components of nerve tissue, including the cell body, axons, and the role of ion gradients in bioelectricity. Test your knowledge on how these elements work together to enable nerve signaling.
