Neuroscience Quiz: MRI and Spinal Cord Functions

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Questions and Answers

What primarily differentiates functional magnetic resonance imaging (fMRI) from traditional MRI?

fMRI is used exclusively for spinal cord analysis.

fMRI measures brain structure.

fMRI provides a static image of the brain.

fMRI detects changes associated with blood flow. (correct)

Which structure is responsible for serving as a link between the brain and the rest of the body?

Peripheral nerves

Cerebellum

Spinal cord (correct)

Cerebrum

Which components of the spinal cord carry signals from the brain to the spinal nerves?

Ascending tracts

Descending tracts (correct)

Cervical nerves

Efferent fibers

What is the primary function of afferent fibers in the spinal cord?

To transmit signals from peripheral tissues to the spinal cord. Signup and view all the answers

Which statement about nerves and neurons is accurate?

A nerve is a bundle of neuronal axons enclosed by connective tissue. Signup and view all the answers

What structure is mainly responsible for the formation of the blood-brain barrier (BBB)?

Astrocytes Signup and view all the answers

Where is the gray matter located in the spinal cord?

Interior of the spinal cord Signup and view all the answers

What is the role of cerebrospinal fluid (CSF)?

To facilitate exchange of materials and protect the brain Signup and view all the answers

Which type of neuron has a single axon and is often fused with its dendrite?

Pseudounipolar neuron Signup and view all the answers

Which area of the brain is primarily involved in language comprehension?

Wernicke's area Signup and view all the answers

Which of the following components are part of the protective structures of the central nervous system?

Meninges and cerebrospinal fluid Signup and view all the answers

What type of fluid is found in the brain's ventricles and protects the brain during sudden movements?

Cerebrospinal fluid (CSF) Signup and view all the answers

What term describes the uneven distribution of sensory and motor cortex areas depicted in the homunculus?

Cortical plasticity Signup and view all the answers

Which type of glial cell is primarily involved in the maintenance and repair of neural tissue?

Microglia Signup and view all the answers

Which division of the peripheral nervous system is responsible for voluntary actions?

Somatic nervous system Signup and view all the answers

What is the main function of the cerebellum?

Subconscious coordination of motor activity Signup and view all the answers

What is the primary role of oligodendrocytes in the nervous system?

Myelinating axons Signup and view all the answers

What is a major characteristic of the cerebral cortex?

It is highly convoluted Signup and view all the answers

What is temporal summation primarily characterized by?

A single presynaptic neuron firing multiple times in close succession Signup and view all the answers

Which process involves multiple presynaptic inputs influencing a single postsynaptic neuron?

Spatial summation Signup and view all the answers

What is the outcome of long-term potentiation (LTP)?

Strengthening of synaptic connections Signup and view all the answers

In which scenario would a decrease in neurotransmitter release likely occur?

During high frequency stimulation causing desensitization Signup and view all the answers

Which type of memory lasts the longest?

Long-term memory Signup and view all the answers

What role does the process of consolidation play in memory?

Transfers short-term memory into long-term storage Signup and view all the answers

What characterizes the divergent pathway in neuronal processing?

Single neuron connecting with multiple postsynaptic neurons Signup and view all the answers

What structural change can occur during memory formation?

Formation of new synapses Signup and view all the answers

What initiates the action potential in a neuron?

Axon hillock activation Signup and view all the answers

What is primarily affected in multiple sclerosis?

Myelin sheath integrity Signup and view all the answers

Which change occurs at an excitatory synapse?

Depolarization leading to an action potential Signup and view all the answers

What happens to Na+ ions during saltatory conduction?

They reinforce depolarization at the nodes of Ranvier. Signup and view all the answers

What type of membrane potential change occurs during an inhibitory synapse?

Small hyperpolarization Signup and view all the answers

How does cocaine affect neurotransmitter transmission?

Inhibits dopamine breakdown at the synaptic cleft. Signup and view all the answers

What is the primary function of the axon in a neuron?

Conducting action potentials to other cells Signup and view all the answers

Which type of ion channels are always open and allow potassium ions to move freely across the membrane?

Leaky channels Signup and view all the answers

What is the primary event that triggers the generation of an action potential in a neuron?

Membrane depolarization Signup and view all the answers

Which mechanism terminates synaptic transmission?

Endocytosis of neurotransmitter receptors Signup and view all the answers

What is a key characteristic of graded potentials?

Their amplitude diminishes with distance. Signup and view all the answers

Which ion primarily causes the depolarization phase of an action potential?

Na^+ Signup and view all the answers

During which phase of an action potential does potassium ion efflux primarily occur?

Repolarization Signup and view all the answers

What distinct feature does a synapse have?

Specific neurotransmitter release Signup and view all the answers

What is the state called when a neuron cannot generate another action potential immediately after one has occurred?

Absolute refractory period Signup and view all the answers

What characterizes a graded potential compared to an action potential?

It is dependent on the strength of the trigger. Signup and view all the answers

Which of the following neurotoxins blocks voltage-gated sodium channels?

Tetrodotoxin (TTX) Signup and view all the answers

Which structure in the neuron contributes to the formation of synapses?

Dendritic spine Signup and view all the answers

What is the primary role of myelin in neurons?

Insulate axons and speed up conduction Signup and view all the answers

During the hyperpolarization phase of an action potential, which ion channel closes slowly?

K^+ channel Signup and view all the answers

What effect does tetrodotoxin (TTX) have on neuronal function?

Prevents generation of action potentials Signup and view all the answers

What change occurs in the membrane potential during depolarization?

Decreased negativity Signup and view all the answers

Which ion movement is responsible for the repolarization phase of the action potential?

K^+ efflux Signup and view all the answers

In which type of conduction does the action potential jump from node to node?

Saltatory conduction Signup and view all the answers

Study Notes

Human Physiology BIOL3205 - Nervous System I - Structure

The nervous system comprises three components: central, peripheral, and enteric.
The central nervous system (CNS) consists of the brain and spinal cord.
The peripheral nervous system (PNS) encompasses both afferent and efferent divisions.
The somatic nervous system controls voluntary actions.
The autonomic nervous system regulates involuntary actions, which are further divided into sympathetic and parasympathetic systems.
The enteric nervous system manages digestion and is part of the autonomic system.

Nervous System Structure I - Cells

Glial cells account for 90% of brain volume, supporting neurons structurally and metabolically.
Astrocytes, star-shaped cells, maintain the spatial relationships within the CNS.
Astrocytes create the blood-brain barrier (BBB), transferring nutrients from the blood to neurons and clearing toxic byproducts.
Oligodendrocytes produce the myelin sheath, crucial for nerve impulse transmission.
Microglia are inactive cells that remove foreign invaders or tissue debris, playing roles in neurodegenerative diseases.
Ependymal cells form the lining of the ventricles and create cerebrospinal fluid (CSF).

Nervous System Structure I - Gray and White Matter

Grey matter contains densely packed cell bodies (non-myelinated).
White matter comprises myelinated axons.
The brain's superior region contains grey matter, while the interior has white matter.
The spinal cord has superior white matter and interior grey matter.
Impulse transmission speed varies based on myelination.

Nervous System Structure I - Protection

The CNS is protected by the cranium (skull) and vertebral column.
Protective membranes called meninges (dura mater, arachnoid mater, pia mater) surround the brain and spinal cord.
Cerebrospinal fluid (CSF) cushions the CNS and maintains a consistent environment.
The blood-brain barrier (BBB) selectively regulates the substances entering the brain.

Nervous System Structure I - Brain

The brain begins as a hollow tube during embryonic development, retaining this structure throughout formation.
The brain contains four interconnected ventricles (two lateral ventricles, third ventricle, and fourth ventricle).
The fourth ventricle extends into the spinal cord as a central canal, containing cerebrospinal fluid.

Nervous System Structure I - Cerebral Spinal Fluid (CSF)

CSF volume is approximately 150 ml.
CSF has a similar density to the brain, enabling it to float or suspend brain tissues.
CSF is manufactured by choroid plexuses, specialized structures in the brain's ventricles.
CSF flows through the ventricles and into the spinal cord's central canal.
CSF is reabsorbed into the subarachnoid space.
CSF safeguards the brain from impact damage.

Nervous System Structure I - Brain Injury

Coup injuries occur when the brain strikes the skull on the same side of impact.
Contrecoup injuries occur when the brain strikes the opposite side of the skull from impact.
Shaken baby syndrome can cause neurological damage.

Nervous System Structure I - Cerebral Spinal Fluid Composition

Cerebrospinal fluid (CSF) contains substances like Na+, K+, Ca2+, Cl-, HCO3−, PCO2, differing from blood composition.
Lower K+ levels exist in CSF in comparison to blood.
CSF contains smaller amounts of protein.
CSF facilitates ion transport, crucial for neural impulses.

Nervous System Structure I - Brain Organization

Brainstem is responsible for vegetative functions.
Cerebellum manages subconscious coordination of motor activity.
Forebrain components include the diencephalon (hypothalamus for homeostasis, thalamus for sensory processing) and the cerebrum (basal nuclei for coordinating movement and cerebral cortex for decision-making).

Nervous System Structure I - Functional Areas of the Cortex

Divided into distinctive areas like frontal lobe, parietal lobe, occipital lobe, and temporal lobe.
Subdivided further by specific functions, such as primary motor cortex, somatosensory cortex.

Nervous System Structure I - Homunculus

Depicts the location and relative amount of cortical area dedicated to sensory input and motor output.
Distribution within the brain is uneven.
Sensitivity and movement precision are unevenly distributed.
The homunculus varies among individuals, adaptable (plasticity).

Nervous System Structure I - Neuron vs. Nerve

Nerves are bundles of peripheral neuronal axons encased by connective tissue.
Nerves have a similar pathway.
Nerves do not contain complete neurons.
Fibers within a nerve don't influence each other.
Nerves in the CNS are called tracts, lacking the same structure as peripheral nerves.

Nervous System Structure I - Renewal of Neurons

Most neurons are generated during embryonic development and remain throughout life.
Ependymal cells are neural stem cells.
New neurons are produced in the hippocampus.
Neurogenesis occurs in the hippocampus, new neurons actively formed, die and are replaced, part of the neurogenesis process.

Nervous System Structure I - Lecture Summary

The aim of the lecture series is to elucidate the structure and functions of the central and peripheral nervous systems, encompassing the cellular mechanisms, protective mechanisms (like the blood-brain barrier), and functions of brain regions. This includes neuron vs. nerve, regeneration, and methods for identifying active brain regions in terms of correlation and fMRI or MRI.

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Description

Test your knowledge on the differences between functional magnetic resonance imaging (fMRI) and traditional MRI, as well as the roles of various structures in the spinal cord. This quiz covers key concepts related to neural communication and the anatomy of the nervous system. Challenge yourself and enhance your understanding of neuroscience!