Anatomy Test 2 Flashcards

Questions and Answers

Which criterion is used to functionally classify neurons?

The direction in which the nerve impulse travels relative to the central nervous system.

During depolarization, which gradient(s) move(s) Na+ into the cell?

Both the electrical and chemical gradients.

The membranes of neurons at rest are very permeable to _ but only slightly permeable to _.

K+; Na+

In which direction is each ion pumped by the Na+-K+ pump?

Na+ is pumped out of the cell and K+ is pumped into the cell. Signup and view all the answers

The concentrations of which two ions are highest outside the cell?

Na+ and Cl- Signup and view all the answers

Why are some forms of MS characterized by periods of remission and exacerbation?

The axons are not damaged; sodium channels appear spontaneously in demyelinated fibers. Signup and view all the answers

Which of the following are bundles of neurofilaments important in maintaining the shape and integrity of neurons?

Neurofibrils Signup and view all the answers

Which of the following is NOT a functional classification of neurons?

Multipolar Signup and view all the answers

Which type of glial cell monitors the health of neurons and can transform into macrophages?

Microglia Signup and view all the answers

Why does injection of a local anesthetic into a finger cause a loss of sensation of touch?

Action potentials are not initiated because propagation requires voltage-gated Na+ channels. Signup and view all the answers

The period after an initial stimulus when a neuron is not sensitive to another stimulus is the?

Absolute refractory period Signup and view all the answers

Which best characterizes depolarization?

Small consecutive steps of Na+ penetration into the axon along its length. Signup and view all the answers

Which statement best describes exocytosis?

Membrane organelles fuse with the membrane and release contents out of the cell. Signup and view all the answers

What conditions will increase the diffusion of neurotransmitters?

An increase in the amount of neurotransmitter exocytosed by the presynaptic axon. Signup and view all the answers

Which best represents synaptic transmission?

Presynaptic axon to synapse to dendrite or postsynaptic cell body. Signup and view all the answers

The small space between the sending neuron and the receiving neuron is the?

Synaptic cleft Signup and view all the answers

A molecule that carries information across a synaptic cleft is a?

Neurotransmitter Signup and view all the answers

What happens when calcium ions enter the synaptic terminal?

They cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane. Signup and view all the answers

What occurs when neurotransmitter molecules bind to receptors in the receiving neuron?

Ion channels in the plasma membrane of the receiving neuron open. Signup and view all the answers

If a signal from a sending neuron makes the receiving neuron more negative inside, what occurs?

The receiving neuron is less likely to generate an action potential. Signup and view all the answers

Which is an excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle?

Acetylcholine Signup and view all the answers

Which of the following is not a chemical class of neurotransmitters?

Nucleic acid Signup and view all the answers

Which neurotransmitter inhibits pain and is mimicked by morphine?

Endorphin Signup and view all the answers

Which neuron circuit pattern is involved in the control of rhythmic activities such as breathing?

Reverberating circuit Signup and view all the answers

Nerve cell adhesion molecules (N-CAMs) ________.

Are crucial for the development of neural connections. Signup and view all the answers

Study Notes

Neuron Classification and Function

Neurons are functionally classified based on the direction of the nerve impulse relative to the central nervous system.
Neurotransmitter release and receptor binding influence neuronal activity, affecting whether an action potential is generated.

Action Potentials and Ion Movement

During depolarization, sodium ions (Na+) move into the cell driven by both electrical and chemical gradients.
Resting neuron membranes are highly permeable to potassium ions (K+) but only slightly to sodium ions (Na+).
The Na+-K+ pump actively transports Na+ out of the cell and K+ into the cell to offset ion leakage.
The absolute refractory period refers to the time after an initial stimulus during which the neuron cannot respond to another stimulus.

Molecular Mechanisms in Neural Activity

Local anesthetics block voltage-gated Na+ channels, inhibiting action potential generation despite activation of mechanically gated ion channels.
Exocytosis involves membrane organelles fusing with the membrane, releasing contents out of the cell.

Synaptic Transmission

The synaptic cleft is the small gap between the sending and receiving neurons where neurotransmission occurs.
Calcium ions entering the synaptic terminal trigger vesicles containing neurotransmitters to fuse with the sending neuron's plasma membrane.

Neurotransmitters and Their Effects

Acetylcholine acts as an excitatory neurotransmitter for skeletal muscle.
Endorphins are neurotransmitters that inhibit pain, mimicking the effects of substances like morphine and heroin.
Intensity of neuronal signaling can be influenced by the quantity of neurotransmitter released at synapses.

Neuronal Structure and Support

Neurofibrils are important bundles of neurofilaments that help maintain the shape and integrity of neurons.
Microglia are glial cells that support neurons' health and can act as macrophages during injury.

Neuronal Circuit Patterns

Reverberating circuits are associated with controlling rhythmic activities, such as breathing.

Neural Development

Nerve cell adhesion molecules (N-CAMs) play a critical role in developing neural connections.

Ion Concentrations

Sodium (Na+) and chloride (Cl-) ions have the highest concentrations outside the cell, influencing membrane potential and action potential generation.

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Description

Review key concepts in neural anatomy with these flashcards. This quiz covers the classification of neurons, depolarization processes, and membrane permeability. Ideal for students preparing for their anatomy exams.