Nervous System and Homeostasis Quiz

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Questions and Answers

What is the primary role of the nervous system in maintaining homeostasis?

To reduce metabolic activity

To store sensory information

To regulate all bodily functions rapidly (correct)

To increase body temperature

Which structure is NOT part of the central nervous system?

Motor neurons (correct)

Brain

Spinal cord

Interneurons

What is the primary function of sensory neurons?

To conduct nerve impulses

To control voluntary movements

To gather information from sensory organs (correct)

To send information to and from the brain

Which of the following best describes glial cells?

Support metabolic activities Signup and view all the answers

What role do interneurons play in the nervous system?

Process and relay information within the CNS Signup and view all the answers

In the context of a reflex arc, which component processes the information received from sensory neurons?

Interneurons Signup and view all the answers

Which of the following correctly describes the somatic division of motor neurons?

Regulates voluntary muscle movement Signup and view all the answers

Which part of the neural pathway is involved when dodging a wayward tennis ball?

Interneuron processes information Signup and view all the answers

What is the primary function of dendrites in a neuron?

To receive information from other neurons Signup and view all the answers

What role does the myelin sheath play in neuron function?

It allows for faster transmission of nerve impulses Signup and view all the answers

What is the resting membrane potential typically measured at in a neuron?

-70mV Signup and view all the answers

Which factor significantly contributes to the establishment of the resting membrane potential?

The varying concentrations of ions across the membrane Signup and view all the answers

During depolarization, what change occurs in the neuron's membrane potential?

The inside becomes more positive due to sodium ion influx Signup and view all the answers

What does the 'all-or-none' response refer to in neural activity?

Action potentials either occur fully or not at all Signup and view all the answers

What happens during the repolarization phase of an action potential?

The membrane potential becomes more negative again Signup and view all the answers

Which of the following accurately describes the process of impulse propagation along a neuron?

Action potentials rapidly travel along the axon Signup and view all the answers

What happens immediately after sodium gates open during depolarization?

Sodium ions flow into the cell. Signup and view all the answers

What occurs during the refractory period?

The neuron cannot respond to another stimulus. Signup and view all the answers

How do neurotransmitters influence the postsynaptic neuron?

By binding to receptors and modifying ion channel activity. Signup and view all the answers

What distinguishes excitatory neurotransmitters from inhibitory neurotransmitters?

Excitatory neurotransmitters depolarize the postsynaptic neuron. Signup and view all the answers

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

To break down acetylcholine after its release. Signup and view all the answers

What initiates the release of neurotransmitters from the presynaptic neuron?

Opening of calcium gates. Signup and view all the answers

What type of action do cholinesterase inhibitors have in relation to acetylcholine?

They reduce the breakdown of acetylcholine. Signup and view all the answers

What is the effect of inhibitory neurotransmitters on the postsynaptic membrane?

They hyperpolarize the postsynaptic neuron. Signup and view all the answers

Study Notes

Homeostasis Definition

Homeostasis is a state of dynamic equilibrium within the body.

Nervous System's Role in Homeostasis

The nervous system rapidly regulates bodily functions to maintain homeostasis.

Nervous System Structures & Functions

Central Nervous System (CNS):
- Brain (processes information like thoughts, emotions, actions)
- Spinal cord (conducts information from the brain and controls reflexes).
Peripheral Nervous System (PNS):
- Sensory neurons (afferent): transmit information from sensory organs to the CNS.
- Motor neurons (efferent): transmit information from the CNS to muscles and glands.
  - Somatic division (voluntary movements).
  - Autonomic division (involuntary movements).

Neuron and Glial Cell Comparison

Neurons: Basic building blocks of the nervous system, conduct nerve impulses.
Glial cells: Support neurons structurally and metabolically, do not conduct impulses.

Neuron Types & Functions

Sensory neurons: Gather information from sensory organs and transmit it to the CNS.
Interneurons: Located in the CNS, collect and process information, then send it to the PNS.
Motor neurons: Transmit information from the CNS to muscles and glands.

Neural Pathway for Dodging a Ball

Sensory receptors in the eyes detect the tennis ball.
Sensory neurons send this information to the CNS.
Interneurons quickly process the information in the CNS.
Motor neurons transmit signals to the muscles responsible for dodging the ball.
Muscles move the body.
Withdrawal reflex: Similar but automatic (involuntary) response to a painful stimulus (e.g., a hot object).

Neuron Structure and Function

Neurons are composed of basic structures (draw a picture to label these structures if you have one).

Myelinated Neuron Structure

The myelin sheath is a fatty protective layer around the axon ( composed of schwann cells, has gaps called nodes of ranvier.

Resting Membrane Potential

The resting membrane potential is the voltage difference across a neuron's membrane when it's not stimulated (measured at -70mV).
This potential is maintained by different ion concentrations inside and outside the neuron, sodium-potassium pumps (3 Na+ out, 2 K+ in), and leakiness of potassium channels.

Depolarization and Action Potential

Depolarization is the process of the neuron's membrane becoming more positive. Action Potential is a rapid change in membrane potential. This occurs with the opening and closing of sodium and potassium ion channels.

"All-or-None" Response

The action potential either occurs completely or not at all once triggered.

Repolarization

Repolarization is the restoration of the neuron's resting membrane potential. Sodium channels close and potassium channels open, allowing potassium ions to flow out of the cell. The sodium-potassium pumps restore ion balance. This is critical to allow for further impulses.

Impulse Propagation

An impulse is propagated along the length of a neuron. Resting potential reaches a threshold, sodium gates open, depolarization happens causing sodium gates to close, potassium gates open repolarization occurs, and then refractory period.

Synaptic Transmission

Transmission occurs from the presynaptic neuron to the postynaptic neuron. Neurotransmitters are released into the synaptic cleft to bind to post synaptic receptors to create an action potential.
Calcium gates open, neurotransmitters are released into the synaptic cleft. Neurotransmitters bind to receptor sites. Electrical signal is generated in postsynaptic neuron.

Neurotransmitters

Neurotransmitters are chemical messengers that transmit signals between neurons (and from neurons to other cells).

Neurotransmitter Effects

Neurotransmitters can be excitatory, increasing the likelihood of an action potential, or inhibitory, decreasing the likelihood. Different neurotransmitters can have different effects, depending on the specific receptors they bind to.

Acetylcholine and Cholinesterase

Acetylcholine (ACh): A neurotransmitter involved in muscle contraction and other functions.
Cholinesterase: Enzyme that breaks down ACh to prevent prolonged signals.

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Description

Test your knowledge on the role of the nervous system in maintaining homeostasis. This quiz covers key concepts such as the structures and functions of the central and peripheral nervous systems, as well as neuron comparisons. Dive into the essential aspects of how our body regulates its internal environment.