Neurons and Neuroglia

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Which of the following accurately describes the function of myelin in neurons?

Generating electrical signals within the neuron.
Boosting the amplitude of the action potential at Nodes of Ranvier.
Increasing the speed of action potential transmission. (correct)
Receiving incoming signals from other neurons.

What is the primary role of glial cells in the nervous system?

Providing structural and functional support to neurons. (correct)
Directly controlling muscle contractions and glandular secretions.
Generating action potentials in response to stimuli.
Transmitting electrical signals between different brain regions.

How do Nodes of Ranvier contribute to the transmission of electrical signals along an axon?

By boosting the amplitude of the action potential. (correct)
By producing myelin to speed up signal transmission.
By insulating the axon to prevent signal loss.
By generating the initial action potential.

What does it mean for neurons to be classified as 'excitable cells'?

They can generate and transmit electrical signals. (D) Signup and view all the answers

Which of the following components of a neuron is primarily responsible for receiving incoming signals from other neurons?

Dendrites (B) Signup and view all the answers

What is the primary function of the blood-brain barrier?

To prevent unwanted substances from entering the brain from the bloodstream. (B) Signup and view all the answers

Which of the following is NOT a primary role of cerebrospinal fluid (CSF)?

Filtering blood to remove pathogens. (A) Signup and view all the answers

Cerebrospinal fluid (CSF) is produced by the:

Choroid plexus in the ventricles. (B) Signup and view all the answers

What is the role of arachnoid granulations in the circulation of cerebrospinal fluid (CSF)?

To return CSF to the venous circulation. (A) Signup and view all the answers

Where does cerebrospinal fluid (CSF) go after circulating through the subarachnoid space?

It enters the central canal of the spinal cord or circulates to the arachnoid granulations. (B) Signup and view all the answers

The rate of CSF production is normally equal to the rate of CSF absorption and independent of:

blood or intracerebroventricular pressure (B) Signup and view all the answers

Where do CSF and interstitial fluid interact in the perivascular space?

Alongside blood vessels that course throughout the brain (A) Signup and view all the answers

What is the significance of the retrograde influx of CSF into the brain parenchyma?

Facilitates interaction between CSF and interstitial fluid for nutrient/waste exchange. (D) Signup and view all the answers

Astrocytes facilitate the removal of inflammatory waste proteins from the brain by:

Transporting fluid through the perivascular space to remove the waste. (C) Signup and view all the answers

Which of the following describes the correct flow of cerebrospinal fluid (CSF) from production to absorption?

Choroid plexuses → ventricles → subarachnoid space → arachnoid granulations. (A) Signup and view all the answers

What would be the most likely implication of finding elevated levels of protein in a patient's CSF during a medical evaluation?

Indication of a compromised blood-brain barrier or other health condition. (A) Signup and view all the answers

Why is it important that the levels of glutamate in CSF are tightly controlled?

Glutamate is a key excitatory neurotransmitter in the CNS, and its concentration affects neuronal signalling. (B) Signup and view all the answers

Which of the following is the primary role of the blood-brain barrier (BBB)?

To regulate molecular passage into the brain and protect it from harmful substances. (D) Signup and view all the answers

What is the main function of the neurovascular unit in the brain?

To ensure proper brain function through the coordinated activity of various cell types. (C) Signup and view all the answers

If a toxin were to enter the bloodstream, which component would primarily be responsible for preventing its entry into the brain tissue?

The blood-brain barrier. (D) Signup and view all the answers

Which component of the neurovascular unit is primarily responsible for regulating blood flow by contracting or relaxing around blood vessels?

Pericytes (C) Signup and view all the answers

How do the meningeal lymphatic vessels contribute to maintaining a healthy brain environment?

By draining inflammatory waste products from the subarachnoid space. (D) Signup and view all the answers

What is the main function of astrocyte foot processes in relation to the blood-brain barrier?

To enhance the barrier by supporting tight junction integrity. (D) Signup and view all the answers

How do astrocytes contribute to the function of neurons within the CNS?

By exchanging nutrients and waste products between blood vessels and neurons. (B) Signup and view all the answers

Which characteristic of molecules allows them to passively cross the blood-brain barrier?

Lipid-soluble properties (A) Signup and view all the answers

What is the primary role of microglia within the neurovascular unit?

Providing immune surveillance and defense (A) Signup and view all the answers

If a drug is developed that is water-soluble and relatively large, what modification would likely be necessary for it to effectively target the brain?

Any of the above. (D) Signup and view all the answers

Although neurons are critical to the CNS, glial cells are more numerous. What is the ratio of glial cells to neurons in the CNS?

3:1 (D) Signup and view all the answers

Which of the following best describes the primary function of the neuronal cell body?

Synthesizing proteins and managing genetic information (C) Signup and view all the answers

Which of the following scenarios would most likely lead to hyperpolarization of a neuron's membrane?

Influx of chloride ions ($Cl^−$) into the cell. (A) Signup and view all the answers

What is the primary role of action potentials in neuronal communication?

To transmit electrical signals over long distances along the axon. (A) Signup and view all the answers

What distinguishes chemical synapses from electrical synapses?

Chemical synapses allow for inhibitory signals, while electrical synapses are primarily excitatory. (C) Signup and view all the answers

A scientist is studying a neuron and observes that its membrane potential is consistently measured at -90 mV. What is the most likely explanation for this observation?

The neuron is hyperpolarized relative to its resting state. (A) Signup and view all the answers

If a drug blocks voltage-gated sodium channels in a neuron, what effect would this have on action potentials?

It would prevent the depolarization phase of the action potential. (A) Signup and view all the answers

A researcher discovers a new neurotransmitter that causes the opening of potassium channels in the postsynaptic membrane. What effect would be mediated by the new neurotransmitter?

Hyperpolarization of the postsynaptic membrane. (D) Signup and view all the answers

How does the 'all-or-nothing' principle apply to action potentials?

An action potential is only triggered if the stimulus reaches a certain threshold. (A) Signup and view all the answers

Why do cerebellar Purkinje cells have such a high number of synaptic connections?

To integrate a large amount of information for precise motor control. (C) Signup and view all the answers

What primarily determines the diversity in signaling between neurons?

The specific neurotransmitter present and the receptors on the adjacent cell. (A) Signup and view all the answers

A drug that selectively blocks G protein-coupled receptors would primarily affect which aspect of neuronal signaling?

Activating intracellular signaling pathways via enzyme systems. (B) Signup and view all the answers

How does the activation of an ion channel-coupled receptor typically affect the neuronal membrane?

It allows specific ions to pass through, potentially causing depolarization or hyperpolarization. (B) Signup and view all the answers

Which of the following is a distinguishing characteristic of neuropeptides compared to other neurotransmitters?

They work more slowly and have longer-lasting effects. (C) Signup and view all the answers

What is the primary reason for the human brain's high metabolic rate?

The extensive network of neurons and neuronal connections. (D) Signup and view all the answers

If a neurotransmitter can bind to both ion channel-coupled receptors and G protein-coupled receptors, what is the most likely result?

The neuron will undergo rapid changes in membrane potential and activate intracellular signaling pathways. (D) Signup and view all the answers

How does the composition of receptor subunits affect ion channel-coupled receptors?

It influences to which ions the channel is permeable. (A) Signup and view all the answers

Knowing that the human brain consumes approximately 15% of the body's cardiac output, which of the following is the most likely consequence of a significant reduction in blood flow to the brain?

Impairment of neuronal signaling and potential neuronal damage. (B) Signup and view all the answers

Cerebrospinal Fluid (CSF)

Fluid that cushions the brain and spinal cord, exchanges nutrients/waste, and maintains a stable chemical environment for neuronal signaling.

Blood-Brain Barrier

A collective term for four sites that prevent unwanted substances in the bloodstream entering the brain.