Nervous System Anatomy & Physiology

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Questions and Answers

How is the nerve stimulated?

The nerve is stimulated by chemicals

The nerve is stimulated by heat

An electrode delivers a small electrical impulse that triggers a signal to be sent along the nerve fiber to the brain or muscle causing a response like a sensation or muscle contraction (correct)

A small electrical impulse is sent along the nerve fiber, which causes the release of neurotransmitters

What signals acetylcholine release?

An action potential reaches the axon terminus, which causes the voltage-gated calcium channels to open. This allows calcium to flow into the cell, triggering the release of acetylcholine.

What is the main neurotransmitter in the nervous system?

Glutamate

What is EPSP?

Excitatory Postsynaptic Potential (EPSP) is a temporary depolarization of the neuron's membrane potential, making it more likely to fire an action potential. Signup and view all the answers

What is the difference between special and temporal summation?

SS: multiple neurons fire at the same time at different places on the postsynaptic neuron adding their signals together to reach the threshold for an action potential; TS: one neuron fires rapidly in succession causing the postsynaptic potential to build up over time to reach the threshold for an action potential (C) Signup and view all the answers

What are all the anatomical parts of a nerve and what happens at each part?

Axons: cord-like groups of fibers in the center of your nerve; Dendrites: branches that carry electrical impulses; Endoneurium: a layer of connective tissue that surrounds a group of axons (fascicles) (B) Signup and view all the answers

What is the difference between the central and peripheral nervous system?

CNS: consists of the brain and spinal cord; PNS: made up of all the nerves that branch out from the spinal cord and extend to the rest of the body (D) Signup and view all the answers

What are the different types of neurons?

Motor (control muscle movements); Sensory (carries sensory info to the brain and spinal cord); Interneurons (located between the sensory and motor neurons); Unipolar: one axon that splits into dendrites; Bipolar: one axon and one dendrite extending from the body; Multipolar: one axon and multiple dendrites extending from the body (B), Motor (control muscle movements); Sensory (carries sensory info to the brain and spinal cord); Interneurons (located between the sensory and motor neurons); Unipolar: one axon that splits into dendrites; Bipolar: one axon and one dendrite extending from the body; Multipolar: one axon and multiple dendrites extending from the body (D) Signup and view all the answers

What is the difference between the somatic and autonomic nervous systems?

SNS: controls voluntary movements (walking, reaching, etc); ANS: regulates the involuntary bodily functions (heart rate, digestion, breathing, etc) (A) Signup and view all the answers

What is the difference between the efferent and afferent divisions of the nervous system?

AD: carries sensory information from the body towards the CNS; ED: carries motor commands from the CNS to the muscles/glands (C) Signup and view all the answers

What are the different types of neuroglia and what are their functions?

Astrocytes: maintaining the extracellular environment (providing nutrients to neurons, regulating blood flow, and guiding neural developments); Oligodendrocytes (CNS): produce myelin sheaths that insulate the axons of neurons, facilitating rapid signal transmission; Microglia (CNS): acts as the immune cells of the CNS (engulfs debris, pathogens, and damaged cells through phagocytosis); Schwann cells (PNS): produce myelin sheaths around the axons of peripheral neurons; Satellite cells (PNS): surround the neuron cell bodies providing structural support and regulating the microenvironment around the neurons (B), Astrocytes: maintaining the extracellular environment (providing nutrients to neurons, regulating blood flow, and guiding neural developments); Oligodendrocytes (CNS): produce myelin sheaths that insulate the axons of neurons, facilitating rapid signal transmission; Microglia (CNS): acts as the immune cells of the CNS (engulfs debris, pathogens, and damaged cells through phagocytosis); Schwann cells (PNS): produce myelin sheaths around the axons of peripheral neurons; Satellite cells (PNS): surround the neuron cell bodies providing structural support and regulating the microenvironment around the neurons (D) Signup and view all the answers

What is the function of the sodium-potassium pump?

The sodium-potassium pump actively transports sodium ions out of the cell and potassium ions into the cell, maintaining the concentration gradients that are essential for nerve impulse transmission. Signup and view all the answers

What are the different types of channels and gates in the nerve cell?

Voltage-gated channels (sodium and potassium); Ligand-gated channels – also known as chemically gated channels (activated by chemical signals); Mechanically-gated channels (A), Voltage-gated channels (sodium and potassium); Ligand-gated channels – also known as chemically gated channels (activated by chemical signals); Mechanically-gated channels (C) Signup and view all the answers

What is the difference between repolarization, depolarization, and hyperpolarization?

RP: the return of the membrane potential to its resting state caused by efflux of potassium ions; DP: cell membrane becoming becoming less negative (more positive) due to influx of positive ions; HP: when the membrane potential becomes even more negative than the resting state due to continued potassium ion outflow (B), RP: the return of the membrane potential to its resting state caused by efflux of potassium ions; DP: cell membrane becoming becoming less negative (more positive) due to influx of positive ions; HP: when the membrane potential becomes even more negative than the resting state due to continued potassium ion outflow (D) Signup and view all the answers

What is the difference between voltage-gated and chemically gated channels?

VG: opens and closes in response to changes in the membrane potential of a cell; CG: opens and closes when a specific chemical molecule binds to it (A), VG: opens and closes in response to changes in the membrane potential of a cell; CG: opens and closes when a specific chemical molecule binds to it (D) Signup and view all the answers

What is the structural classification for neurons and which one is most abundant in the CNS (central nervous system)?

Multipolar - most abundant; Bipolar; Unipolar (A), Multipolar - most abundant; Bipolar; Unipolar (B) Signup and view all the answers

What happens when the sodium and potassium channels open and how does it affect the cell polarity?

The opening of the sodium channels leads to a positive shift in cell polarity, whereas the opening of potassium channels leads to a negative shift (A) Signup and view all the answers

What are the main steps in the generation of an action potential?

Depolarization (sodium influx); Reaching the threshold potential; Rapid sodium channel opening; Overshoot (positive peak due to influx of sodium ions); Repolarization (potassium efflux); Hyperpolarization (membrane potential slightly dips) (B), Depolarization (sodium influx); Reaching the threshold potential; Rapid sodium channel opening; Overshoot (positive peak due to influx of sodium ions); Repolarization (potassium efflux); Hyperpolarization (membrane potential slightly dips) (D) Signup and view all the answers

What is the none-or-all principle?

A response to a stimulus will either be a full, complete response or there will be no response at all (the strength of the stimulus doesn't affect the intensity of the response if it reaches the threshold for activation (C) Signup and view all the answers

What is the threshold?

The minimum level of energy or membrane potential that must be reached to trigger a physiological or psychological response (A) Signup and view all the answers

What is the difference between absolute refractory and relative refractory?

AR: the cell is unresponsive; RR: the cells get gradually more responsive, but still require a strong stimulus to trigger a response (A) Signup and view all the answers

What are myelinated and unmyelinated neurons used for and how/when do they develop?

Myelinated neurons transmit nerve impulses quickly, while unmyelinated neurons transmit nerve impulses more slowly. Myelination is the process of wrapping axons in myelin, a fatty substance that insulates the axon, allowing electrical impulses to jump between nodes of Ranvier. This process begins during fetal development and continues into adulthood. Signup and view all the answers

How do neurons stimulate and how do they conduct information?

Neurons stimulate each other by sending electrical impulses (action potentials) along axons, which trigger the release of chemical messengers (neurotransmitters) across the synapse to reach the dendrites of the receiving neuron. Signup and view all the answers

Study Notes

Nervous System Anatomy & Physiology

Nerve stimulation occurs via electrical impulses triggering a signal along nerve fibers to the brain or muscles.
Acetylcholine release is triggered by an action potential reaching axon terminals, causing voltage-gated calcium channels to open, which in turn triggers acetylcholine release.
Glutamate is a key neurotransmitter in the nervous system.
EPSP (Excitatory Postsynaptic Potential) is a temporary depolarization of the neuron membrane potential.
IPSP (Inhibitory Postsynaptic Potential) is an electrical signal that makes a neuron less likely to fire (hyperpolarizing the membrane).
Temporal summation occurs when one neuron fires rapidly, causing the postsynaptic potential to build up over time until reaching the threshold for an action potential.
Spatial summation occurs when multiple neurons fire simultaneously at different points on a postsynaptic neuron, adding their signals together to reach a threshold.
Nerves have axons, dendrites, endoneurium, and fascicles; dendrites carry impulses, axons are the core structure, and endoneurium is around each axon group.
CNS (Central Nervous System) includes brain and spinal cord; PNS (Peripheral Nervous System) connects these to the body.
Neurons are categorized as motor, sensory, or interneurons; depending on their role in body function.
Unipolar neurons have one axon that splits into dendrites.
Bipolar neurons have one axon and one dendrite.
Multipolar neurons have one axon and multiple dendrites.
The somatic nervous system controls voluntary movements (walking, reaching, etc).
The autonomic nervous system controls involuntary functions (heart rate, digestion, breathing, etc).
Astrocytes maintain the extracellular environment, regulate blood flow, and guide neural development in the CNS.
Oligodendrocytes create myelin sheaths around axons, facilitating rapid signal transmission.
Microglia act as the immune cells of the CNS, engulfing debris and pathogens, and damaged cells.
Schwann cells produce myelin sheaths around axons in the PNS.
Satellite cells surround the neuron cell bodies in the PNS, providing support and regulating the microenvironment.
The sodium-potassium pump actively transports sodium out of the cell and potassium into the cell.
Nerve cells have voltage-gated ion channels that open and close in response to changes in membrane potential and chemically gated channels that open in response to a chemical signal.
Depolarization is where a cell membrane becomes less negative and hyperpolarization is when a cell membrane becomes more negative than resting potential.
Action potentials have distinct phases: depolarization (sodium influx), overshoot, repolarization (potassium efflux), and hyperpolarization.
Continuous propagation occurs in unmyelinated axons gradually, while saltatory propagation occurs along myelinated axons more rapidly, jumping between nodes of Ranvier.
Threshold is the minimum membrane potential required to trigger a physiological or psychological response.
Absolute refractory period is a brief time after an action potential during which a cell cannot fire another action potential; relative refractory period occurs afterwards when it takes more energy to achieve a response.
Myelin is a fatty tissue sheath surrounding some axons, allowing electrical impulses to travel quickly (saltatory propagation) and increasing speed and efficiency of transmission.

Neuron Stimulation & Communication

Neurons stimulate each other by sending electrical impulses (action potentials) along axons; neurotransmitters are released by the sending neuron to communicate across synapses to the receiving neuron.

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Description

Test your knowledge on the anatomy and physiology of the nervous system. This quiz covers nerve stimulation processes, neurotransmitter functions, and the mechanisms of excitatory and inhibitory postsynaptic potentials. Dive deep into the intricacies of neural communication and summation principles.