Integration of Signals

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Questions and Answers

What initiates the opening of voltage-gated Ca2+ channels in the axon terminal?

The arrival of an action potential (correct)

A decrease in membrane potential

The binding of neurotransmitters

Calcium ion levels in the synaptic cleft

What process is triggered by the entry of Ca2+ into the axon terminal?

Reuptake of neurotransmitters

Exocytosis of synaptic vesicles (correct)

Inhibition of action potentials

Opening of sodium channels

Which role does the synaptic cleft play during neurotransmitter release?

It facilitates the binding of neurotransmitters to receptors (correct)

It generates action potentials

It produces new synaptic vesicles

It stores calcium ions

What happens to the neurotransmitter molecules after exocytosis?

They are degraded by enzymes Signup and view all the answers

Which best describes the role of calcium ions during neurotransmitter release?

Calcium ions trigger exocytosis of vesicles Signup and view all the answers

Which mechanism terminates the action potential along an axon?

Opening of potassium channels Signup and view all the answers

How does depolarization affect the postsynaptic cell?

It activates voltage-gated sodium channels Signup and view all the answers

What role does the docking protein play in synaptic transmission?

It anchors vesicles at the membrane Signup and view all the answers

What initiates the release of neurotransmitters from synaptic vesicles?

Entry of calcium ions into the presynaptic terminal Signup and view all the answers

Which of the following steps occurs first during synaptic transmission?

Action potential depolarizes the axon terminal Signup and view all the answers

What is the primary function of neurotransmitters at a chemical synapse?

To bind to receptors on postsynaptic neurons Signup and view all the answers

What happens after neurotransmitters bind to receptors on the postsynaptic cell?

A response is initiated in the postsynaptic cell Signup and view all the answers

Which event occurs first during the transmission at a chemical synapse?

Influx of calcium ions into the presynaptic neuron Signup and view all the answers

Which event directly follows calcium influx in the presynaptic terminal?

Neurotransmitter release into the synaptic cleft Signup and view all the answers

What is the role of the synaptic cleft in neurotransmission?

To facilitate the diffusion of neurotransmitters Signup and view all the answers

What role do docking proteins play in synaptic transmission?

They assist in the fusion of synaptic vesicles with the membrane Signup and view all the answers

How does an action potential lead to neurotransmitter release?

By depolarizing the axon terminal and opening calcium channels Signup and view all the answers

What type of synapse uses neurotransmitters to communicate between neurons?

Chemical synapse Signup and view all the answers

What is the primary cause of the depolarization of the axon terminal during an action potential?

Opening of voltage-gated sodium channels Signup and view all the answers

Which statement best describes the synaptic cleft?

It allows for the rapid diffusion of neurotransmitters Signup and view all the answers

What happens when calcium ions enter the presynaptic neuron?

They trigger synaptic vesicle fusion with the presynaptic membrane Signup and view all the answers

How does the entry of calcium ions (Ca2+) affect synaptic transmission?

It triggers the release of neurotransmitters from synaptic vesicles Signup and view all the answers

What type of electrical signal typically leads to the release of neurotransmitters at a synapse?

Action potential Signup and view all the answers

What is the effect of an excitatory neurotransmitter on a postsynaptic neuron?

It increases the likelihood of an action potential Signup and view all the answers

Study Notes

Lecture 4: Integration of Signals

This lecture covers the integration of signals in the nervous system
Chemical synapses are points of interaction in the nervous system, transmitting electrical signals between cells
Chemical synapses use neurotransmitters (NTs) released from presynaptic neurons to bind to receptors on postsynaptic neurons
Two types of synapses exist
Presynaptic neurons send signals toward a synapse
Postsynaptic neurons transmit signals away from a synapse
The nervous system uses summation of graded potentials to trigger action potentials
Types of summation are temporal and spatial
Temporal summation is when a presynaptic neuron fires repeatedly at high rates
Spatial summation is when multiple presynaptic neurons fire at the same time, creating a larger change in membrane potential
Graded potentials can be excitatory or inhibitory, affecting the likelihood of reaching threshold for an action potential at the axon hillock
Spinal reflexes are simple behaviors produced by the central nervous system pathways entirely in the spinal cord
A reflex arc involves five components: receptor, sensory neuron, integration center, motor neuron, and effector
Examples given for a reflex action are the patellar tendon reflex (also known as the knee-jerk reflex)
Extension is the straightening of a joint, while flexion is bending the joint
Homeostasis is the maintenance of a relatively constant internal environment in the body
Homeostasis is a dynamic process involving mechanisms to regulate body temperature, volume, and composition
Negative feedback is a common control system in the body, responding to deviations from set points by initiating changes in the opposite direction
Excitatory postsynaptic potentials (EPSPs) increase the likelihood of an action potential
Inhibitory postsynaptic potentials (IPSPs) decrease the likelihood of an action potential
Homeostatic control reflex systems maintain body temperature when there are changes in room temperature

Types of neurons

Three types of neurons are present in the nervous system
Sensory neurons carry signals from sensory receptors to the central nervous system
Motor neurons carry signals to effector cells to determine an appropriate effector response
Interneurons play a role integrating information within the central nervous system and connecting to motor neurons. They process signals such as emotions, learning, and memory

Neuronal circuits

Divergence
Information from a single neuron to multiple neurons. A mechanism for spreading signals to multiple neurons in the CNS
Convergence
Several neurons synapse with a single postsynaptic neuron. A mechanism for providing input to a single neuron from multiple sources

Chemical Messengers

Neurotransmitters bind to receptors on postsynaptic neurons to trigger a response.
Autocrine substances affect the same cell that makes them
Paracrine substances affect cells near the source
Hormones travel through the blood to distant target cells in the body

Termination of neurotransmitter Effects

Neurotransmitters are removed from the synaptic cleft
Enzymes inactivate neurotransmitters
Neurotransmitters are reabsorbed into presynaptic terminals or transported into glial cells

Basic Concepts in Biomedical Sciences I

Chapter 2, Homeostasis, pages 8-13 are suggested reading for further study

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Description

This quiz explores the integration of signals within the nervous system, focusing on chemical synapses and neurotransmitter functions. It examines the concepts of graded potentials, action potentials, and the types of summation. Test your knowledge on the dynamics between presynaptic and postsynaptic neurons, as well as the role of spinal reflexes.

Integration of Signals - Lecture 4

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