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Questions and Answers
What triggers the opening of voltage-gated ion channels in the axon?
What triggers the opening of voltage-gated ion channels in the axon?
- An increase in potassium ion concentration
- A sustained resting potential
- A decrease in voltage potential
- A local reversal of the membrane potential (correct)
What happens during the refractory period of an ion channel?
What happens during the refractory period of an ion channel?
- The channel is unable to open for a short duration (correct)
- The channel closes permanently after one action potential
- The channel remains open to maintain action potential
- The channel can open immediately after closing
What is the significance of the all-or-nothing principle of action potentials?
What is the significance of the all-or-nothing principle of action potentials?
- Action potentials can vary in intensity depending on the strength of the stimulus
- Once the threshold is reached, the action potential will always reach +40mV (correct)
- Action potentials can be partially completed if the threshold is not fully reached
- All ion channels must open simultaneously for an action potential to occur
How does the action potential travel along the axon?
How does the action potential travel along the axon?
What prevents the summation of action potentials in the axon?
What prevents the summation of action potentials in the axon?
What structure carries sensory information into the spinal canal?
What structure carries sensory information into the spinal canal?
Which part of the spinal cord contains the cell bodies of motor neurons?
Which part of the spinal cord contains the cell bodies of motor neurons?
What is the purpose of interneurons in the spinal cord?
What is the purpose of interneurons in the spinal cord?
What anatomical feature of the spinal cord is considered to be deeper and wider?
What anatomical feature of the spinal cord is considered to be deeper and wider?
What is the cauda equina?
What is the cauda equina?
How many pairs of spinal nerves are attached to the spinal cord?
How many pairs of spinal nerves are attached to the spinal cord?
What defines the structure of the spinal cord?
What defines the structure of the spinal cord?
Which type of neuron makes up the dorsal root ganglion?
Which type of neuron makes up the dorsal root ganglion?
How many pairs of cervical spinal nerves are there?
How many pairs of cervical spinal nerves are there?
What are dermatomes specifically associated with?
What are dermatomes specifically associated with?
What distinguishes cranial nerves from spinal nerves?
What distinguishes cranial nerves from spinal nerves?
Which of the following cranial nerves is responsible for the sense of smell?
Which of the following cranial nerves is responsible for the sense of smell?
What component of the nervous system primarily regulates involuntary functions?
What component of the nervous system primarily regulates involuntary functions?
Which nervous system is divided into sympathetic and parasympathetic divisions?
Which nervous system is divided into sympathetic and parasympathetic divisions?
What is the primary function of myotomes?
What is the primary function of myotomes?
Which cranial nerve is responsible for controlling the heart rate and digestive tract?
Which cranial nerve is responsible for controlling the heart rate and digestive tract?
Which system is dominant during danger and stressful activities?
Which system is dominant during danger and stressful activities?
What neurotransmitter is released by the postganglionic fibers of the sympathetic nervous system?
What neurotransmitter is released by the postganglionic fibers of the sympathetic nervous system?
What type of receptors are found in the postganglionic fibers of the parasympathetic nervous system?
What type of receptors are found in the postganglionic fibers of the parasympathetic nervous system?
What is the primary change occurring during depolarisation?
What is the primary change occurring during depolarisation?
What happens to the electrical potential during re-polarisation?
What happens to the electrical potential during re-polarisation?
Which statement correctly describes the length of autonomic fibers in the sympathetic nervous system?
Which statement correctly describes the length of autonomic fibers in the sympathetic nervous system?
The action potential moves along the axon in which manner?
The action potential moves along the axon in which manner?
What is the primary function of the parasympathetic nervous system?
What is the primary function of the parasympathetic nervous system?
What triggers the opening of sodium channels during depolarisation?
What triggers the opening of sodium channels during depolarisation?
Where do preganglionic fibers of the sympathetic nervous system originate?
Where do preganglionic fibers of the sympathetic nervous system originate?
What is the resting potential of a neuron?
What is the resting potential of a neuron?
What occurs immediately after the action potential is initiated?
What occurs immediately after the action potential is initiated?
Which type of neurotransmitter is primarily released at the effector in the parasympathetic nervous system?
Which type of neurotransmitter is primarily released at the effector in the parasympathetic nervous system?
Why is it important for the action potential to propagate in one direction along the axon?
Why is it important for the action potential to propagate in one direction along the axon?
What role does sodium ions ($Na^+$) play during the action potential?
What role does sodium ions ($Na^+$) play during the action potential?
What is the result of the voltage-gated sodium channels opening?
What is the result of the voltage-gated sodium channels opening?
What primarily gives gray matter its pinkish-gray color?
What primarily gives gray matter its pinkish-gray color?
Which structures are primarily involved in afferent input in the gray matter?
Which structures are primarily involved in afferent input in the gray matter?
What type of nerve fibers are predominantly found in the white matter?
What type of nerve fibers are predominantly found in the white matter?
What are the bundles of fibers within each funiculus of the white matter called?
What are the bundles of fibers within each funiculus of the white matter called?
Which type of tract carries impulses from the brain down the spinal cord?
Which type of tract carries impulses from the brain down the spinal cord?
What is the function of lateral horns in the gray matter?
What is the function of lateral horns in the gray matter?
What term describes the mixed spinal nerve that carries various signals between the spinal cord and the body?
What term describes the mixed spinal nerve that carries various signals between the spinal cord and the body?
In the gray matter, which of the following structures functions in cross reflexes?
In the gray matter, which of the following structures functions in cross reflexes?
Flashcards
What is gray matter?
What is gray matter?
The gray matter of the spinal cord contains nerve cell bodies, dendrites, unmyelinated axon terminals, and neuroglia. It is pinkish-gray due to its rich network of blood vessels.
What is the shape of the gray matter in the spinal cord?
What is the shape of the gray matter in the spinal cord?
The gray matter forms an H shape in the spinal cord, composed of three columns of neurons, each with a specific function: posterior, anterior, and lateral horns.
What is the function of the posterior horns?
What is the function of the posterior horns?
The posterior horns, located dorsally, function in receiving sensory input (afferent) from the body.
What is the function of the anterior horns?
What is the function of the anterior horns?
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What is the function of the lateral horns?
What is the function of the lateral horns?
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What is white matter composed of?
What is white matter composed of?
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How is the white matter organized?
How is the white matter organized?
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What is the function of the tracts in white matter?
What is the function of the tracts in white matter?
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What is the spinal cord?
What is the spinal cord?
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What is the structure of the spinal cord?
What is the structure of the spinal cord?
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How is the spinal cord connected to the body?
How is the spinal cord connected to the body?
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What is the function of the dorsal nerve root?
What is the function of the dorsal nerve root?
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What is the dorsal root ganglion?
What is the dorsal root ganglion?
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What is the function of the ventral nerve root?
What is the function of the ventral nerve root?
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What are interneurons?
What are interneurons?
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What is the cauda equina?
What is the cauda equina?
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Refractory Period
Refractory Period
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Threshold
Threshold
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Transmission of Impulse
Transmission of Impulse
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Resting Potential
Resting Potential
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Action Potential
Action Potential
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Sympathetic Nervous System
Sympathetic Nervous System
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Parasympathetic Nervous System
Parasympathetic Nervous System
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Neuron
Neuron
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Synaptic Transmission
Synaptic Transmission
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Neurotransmitter
Neurotransmitter
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Synapse
Synapse
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Depolarization
Depolarization
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Repolarization
Repolarization
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Threshold of excitation (TH)
Threshold of excitation (TH)
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Sodium influx
Sodium influx
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Propagation of action potential
Propagation of action potential
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One-dimensional (1D) transmission
One-dimensional (1D) transmission
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What are spinal nerves?
What are spinal nerves?
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How are spinal nerves named?
How are spinal nerves named?
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What are dermatomes?
What are dermatomes?
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What are myotomes?
What are myotomes?
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What are cranial nerves?
What are cranial nerves?
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How are cranial nerves numbered and named?
How are cranial nerves numbered and named?
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What is the autonomic nervous system?
What is the autonomic nervous system?
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What are the sympathetic and parasympathetic divisions?
What are the sympathetic and parasympathetic divisions?
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Study Notes
Organization of the Nervous System (Function) - Part 3
- The nervous system is organized into a structural classification of neurons and neuroglia.
- Neuroglia: Includes astrocytes, ependymal cells, microglial cells, oligodendrocytes, and Schwann cells.
- The brain: Has protective coverings including the cerebrum, cerebellum, brainstem, and diencephalon.
Spinal Cord
- An elongated cylinder, extending from the brainstem through the foramen magnum of the skull.
- Interior gray matter surrounded by white matter.
- Contains 31 pairs of spinal nerves attached by dorsal and ventral nerve roots.
- Lies within the spinal cavity, extending from the foramen magnum to the first lumbar vertebra.
- Oval-shaped, tapering slightly from the top (cervical region) to the bottom (lumbar region).
- Two bulges, one in the cervical region and one in the lumbar region.
- Anterior median fissure and posterior median sulcus, two deep grooves, the anterior fissure is deeper and wider.
Spinal Cord - Nerve Roots
- Fibers of dorsal nerve root carry sensory information into the spinal canal.
- Dorsal root ganglion contains cell bodies of unipolar sensory neurons.
- Fibers of ventral nerve root carry motor information out of the spinal cord.
- Cell bodies of multipolar motor neurons are located in the gray matter of the spinal cord.
Spinal Cord - Cauda Equina
- A collection of spinal nerves extending from the conus medullaris (in the inferior end of the spinal cord).
- Resembling a horse's tail, hence the name.
- Descends through the lower third of the spinal canal.
Gray Matter
- Consists of nerve cell bodies, dendrites, axon terminals (unmyelinated), and neuroglia.
- Pinkish-gray, due to a rich network of blood vessels.
- Forms an "H" shape, composed of three columns of neurons: posterior, anterior, and lateral horns.
- Projections of gray matter towards the outer surface are called horns.
Gray Matter (Function)
- Two dorsal horns function in afferent (sensory) input.
- Two ventral horns function in efferent (motor) somatic output.
- Two lateral horns function in both somatic and autonomic output.
- Gray commissure connects the two halves of the gray matter, associated with cross reflexes.
- Filters information and integrates spinal reflexes.
White Matter
- Composed mostly of myelinated nerve fibers, giving it a whitish color.
- Divided into three pairs of columns (funiculi), anterior, posterior, and lateral, and a commissure area.
- Bundles of fibers within funiculi called fasciculi.
- Ascending tracts carry sensory impulses up the spinal cord to the brain.
- Descending tracts carry motor impulses from the brain down the spinal cord.
Learning Outcome 4
- Defines spinal nerve, dermatome, and myotome.
- Compares somatic motor and autonomic function.
- Compares sympathetic and parasympathetic function.
- Compares the difference in the effects of the autonomic nervous system.
- Describes membrane potentials and impulse transmission.
Cranial Nerves
- 12 pairs of nerves connected to the brain.
- Carry sensory and motor signals.
- Identified by Roman numerals (I-XII).
- Originate and terminate within the brainstem (cranial nerve nuclei).
Somatic vs. Autonomic Nervous Systems
- Somatic: Controls voluntary muscle functions, with one neuron (motor neuron) between CNS and the skeletal muscle. Receives input from sense organs, output to skeletal muscles (muscle contractions). Uses only acetylcholine as neurotransmitter.
- Autonomic: Controls involuntary functions. Two-neuron chain (preganglionic and postganglionic) between CNS and target organ, innervates cardiac, smooth muscle, exocrine, and endocrine glands. Uses acetylcholine or norepinephrine as neurotransmitters.
Sympathetic vs. Parasympathetic Nervous Systems
- SNS (Sympathetic): Active in times of stress, danger, or exertion. Increases blood pressure, heart rate.
- PSNS (Parasympathetic): Active during rest or relaxation. Decreases heart rate, stimulates digestion.
Membrane Potentials
- Resting potential: The negative charge inside the nerve cell when not conducting an impulse.
- Depolarization: Change from negative to positive potential as action potential. Positive ions (sodium) flow in, changing the electrical charge to positive.
- Repolarization: The change back to negative potential as positive sodium ions flow out.
- Threshold: Trigger for the start of an action potential. The stimulus must exceed to trigger an action potential.
- Explains the formation of resting and action potentials.
- Describes mechanisms of impulse transmission and spreading along the axon.
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Description
This quiz explores essential concepts in neuroscience, focusing on ion channels and the anatomy of the spinal cord. It covers topics like action potentials, the refractory period, sensory information pathways, and neuron types. Test your knowledge on the critical structures and functions of the nervous system.
