Nervous System Overview and Functions

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Questions and Answers

What is the main function of the sympathetic nervous system?

Restores and conserves energy

Regulates digestion and energy storage

Promotes relaxation and sleep

Prepares the body for action (correct)

Which neurotransmitter is primarily associated with postganglionic neurons of the sympathetic nervous system?

Noradrenaline (NE) (correct)

Dopamine

Acetylcholine (ACh)

Serotonin

What action is associated with the physiological response of the parasympathetic nervous system?

Rest and digest functions (correct)

Immediate energy release

Enhanced energy expenditure

Increased heart rate

Which statement about neurotransmitters is correct?

Both sympathetic and parasympathetic preganglionic neurons use the same neurotransmitter. Signup and view all the answers

Which of the following is NOT a characteristic function of the sympathetic nervous system?

Conservation of energy Signup and view all the answers

What type of control is associated with the Somatic Nervous System (SNS)?

Voluntary control of skeletal muscles Signup and view all the answers

Which neurotransmitter is primarily associated with the Autonomic Nervous System (ANS)?

Noradrenaline in sympathetic pathways Signup and view all the answers

What is the primary function of the Autonomic Nervous System (ANS)?

Regulating involuntary bodily functions Signup and view all the answers

Which of the following characteristics is NOT true for the Somatic Nervous System (SNS)?

It regulates smooth muscle activity. Signup and view all the answers

Which division of the Autonomic Nervous System is responsible for the 'fight or flight' response?

Sympathetic division Signup and view all the answers

Which target organs are controlled by the Autonomic Nervous System (ANS)?

Smooth muscles and glands Signup and view all the answers

What distinguishes the Somatic Nervous System (SNS) from the Autonomic Nervous System (ANS) in terms of control?

SNS operates consciously, ANS operates unconsciously. Signup and view all the answers

Which of the following functions is NOT controlled by the Autonomic Nervous System (ANS)?

Voluntary muscular movement Signup and view all the answers

What is the primary therapeutic use of physostigmine?

Antidote for anticholinergic toxicity Signup and view all the answers

Which of the following is NOT a side effect of muscarinic cholinergic agonists?

Tachycardia Signup and view all the answers

What is the effect of cholinergic crisis?

Severe muscle weakness and respiratory paralysis Signup and view all the answers

Which of the following medications is classified as an indirect-acting cholinergic agonist?

Rivastigmine Signup and view all the answers

What are common side effects of nicotinic cholinergic agonists?

Muscle cramps and tachycardia Signup and view all the answers

Which symptom is associated with an overdose of cholinergic agonists?

Decreased muscle strength Signup and view all the answers

What is one of the therapeutic uses of Donepezil?

Management of Alzheimer's disease Signup and view all the answers

Which of the following best describes the action of indirect-acting cholinergic agonists?

They enhance acetylcholine availability Signup and view all the answers

What neurotransmitters are primarily associated with the adrenergic system?

Noradrenaline and adrenaline Signup and view all the answers

Which type of adrenergic receptors are involved in negative feedback to reduce noradrenaline release?

Alpha 2 receptors Signup and view all the answers

What type of adrenergic agonists act directly on adrenergic receptors to stimulate them?

Direct-acting adrenergic agonists Signup and view all the answers

Which of the following best describes mixed-acting adrenergic agonists?

They directly stimulate adrenergic receptors and promote catecholamine release. Signup and view all the answers

Which of these options incorrectly describes the function of beta receptors?

Beta receptors exclusively inhibit neurotransmitter release. Signup and view all the answers

What is a common side effect of adrenergic agonists?

Tachycardia Signup and view all the answers

Which classification of adrenergic agonists is characterized by increasing the release of endogenous catecholamines?

Indirect-acting adrenergic agonists Signup and view all the answers

Which adrenergic receptor type is primarily found on presynaptic neurons?

Alpha 2 Signup and view all the answers

What is the primary therapeutic use of adrenaline?

Bronchodilation in asthma Signup and view all the answers

Which adrenergic agonist is specifically used to increase cardiac output in acute heart failure?

Dobutamine Signup and view all the answers

What are common side effects associated with salbutamol?

Tremors and palpitations Signup and view all the answers

What is the action of clonidine in the management of hypertension?

Vasodilation Signup and view all the answers

Which adrenergic agonists are used as decongestants for congested nose?

Phenylephrine and Pseudoephedrine Signup and view all the answers

What is the potential side effect of prolonged use of phenylephrine?

Rebound congestion Signup and view all the answers

Which adrenergic agonist acts by relaxing the muscle of the bladder?

Mirabegron Signup and view all the answers

Which adrenergic agonist is likely to be administered to restore cardiac rhythm during cardiac arrest?

Adrenaline Signup and view all the answers

What is a common side effect of non-selective alpha blockers?

Postural hypotension Signup and view all the answers

Which side effect is primarily associated with selective beta 1 blockers?

Fatigue Signup and view all the answers

What side effect might result from the blockade of α2 receptors by non-selective alpha blockers?

Increased release of norepinephrine Signup and view all the answers

Which of the following is a potential consequence of using non-selective beta blockers?

Hypotension Signup and view all the answers

Which side effect is considered a result of selective alpha 1 blocker activity?

Dizziness Signup and view all the answers

What is a major adverse effect of non-selective beta blockers that can affect asthmatic patients?

Bronchoconstriction Signup and view all the answers

Which of the following side effects is least likely to be caused by selective beta 1 blockers?

Bronchoconstriction Signup and view all the answers

Which adrenergic antagonist is most likely to cause postural hypotension?

Non-selective alpha blocker Signup and view all the answers

Study Notes

Nervous System Objectives

Students should be able to describe the structure of neurons and the function of their components.
Students should be able to list the divisions of the nervous system and describe the characteristics of each.
Students should be able to list the functions of the nervous system.
Students should be able to differentiate between types of neurotransmitters and their functions.
Students should be able to explain how an action potential is generated and propagated.
Students should be able to explain the processes involved in synaptic transmission.
Students should be able to differentiate voluntary neural pathways versus reflex arcs.
Students should be able to explain the structure of neurons, including dendrites, cell bodies, and axons, and the function of glial cells.
Students should be able to categorize neurons as multipolar, bipolar, or unipolar, based on their structure.

Overview of Nervous System

The nervous system is a network of neurons that generate, modulate, and transmit information throughout the human body.

Cells of the Nervous System (Neuron vs Glial Cells)

The nervous system comprises neurons and glial cells.
Neurons generate and transmit nerve impulses.
Glial cells support, nourish, and protect neurons.
Neurons are categorized as multipolar, bipolar, or unipolar based on their structure.

Divisions of the Nervous System

The nervous system is divided into the central nervous system (CNS) and the peripheral nervous system (PNS).
The CNS includes the brain and spinal cord.
The PNS includes cranial nerves, spinal nerves, sensory neurons, and motor neurons.
Sensory neurons transmit information from sensory organs to the CNS.
Motor neurons transmit signals from the CNS to effectors (muscles and glands).
The somatic nervous system controls voluntary movements.
The autonomic nervous system controls involuntary actions.
The sympathetic division is associated with "fight-or-flight."
The parasympathetic division is associated with "rest-and-digest."

CNS vs PNS

The CNS and PNS work together.
The CNS processes information and generates responses.
The PNS relays information between the CNS and the rest of the body.

Somatic vs Autonomic

The somatic nervous system is involved in voluntary actions.
The autonomic nervous system controls involuntary actions.
The sympathetic and parasympathetic divisions have opposing effects.

Neurotransmitters

Neurotransmitters are chemical messengers that transmit signals across synapses.
Excitatory neurotransmitters cause the neuron to fire.
Inhibitory neurotransmitters prevent the neuron from firing.
Neurotransmitters include adrenaline, noradrenaline, dopamine, serotonin, GABA, acetylcholine, glutamate, and endorphins.

How Are Neurotransmitters Removed from Synapse?

Neurotransmitters are removed through diffusion, reuptake (by proteins), and enzymatic degradation.

What Can Go Wrong?

Issues with neurotransmitter production/release, receptor function, and reuptake can disrupt nervous system function.

CNS Stimulants

Central nervous system stimulants include caffeine, nicotine, cocaine, methylphenidate, amphetamines, methamphetamine, modafinil, and phentermine.
Psychomotor stimulants cause increased alertness, attention, energy, and activity.
Hallucinogens distort perception.

Hallucinogens

Marijuana is extracted from cannabis plants.

Cholinergic System

The cholinergic system uses acetylcholine (ACh) as a neurotransmitter.
ACh is crucial in parasympathetic functions and some CNS activities.

Cholinergic Receptors

Two main types of cholinergic receptors are muscarinic and nicotinic.
Muscarinic receptors are generally associated with parasympathetic actions.
Nicotinic receptors are typically found at synapses and neuromuscular junctions.
Different subtypes of muscarinic (M1-M5) and nicotinic receptors (Nn, Nm) are expressed in various parts of the body.

Cholinergic Agonists

Direct-acting agonists bind directly to cholinergic receptors.
Indirect-acting agonists inhibit the enzyme that breaks down ACh.

Cholinergic Antagonists (Antimuscarinics)

Antagonists block ACh actions at the receptor sites.
They cause effects that oppose parasympathetic activity (e.g. increased heart rate, decreased GI motility, etc.).
Examples include atropine, ipratropium, oxybutynin, and tolterodine.

Cholinergic Antagonists (Nicotinic antagonists)

Antagonists block nicotinic receptors.
Examples include rocuronium, which is used for muscle relaxation during surgery and mechanical ventilation.

Neuronal Pathways

Voluntary pathways involve conscious decision-making.
Reflex arcs are automatic responses to stimuli, bypassing the brain.
Both involve neurons (sensory, interneurons, motor) and effector organs.

Action Potential

Action potentials are rapid changes in membrane potentials along neurons.
The resting potential (-70mV) exists due to differing ion concentrations inside and outside the cell.
Depolarization involves opening of voltage-gated sodium channels, increasing membrane potential.
Repolarization reverses the change in voltage due to opening of potassium channels and allows sodium channels to close.
A stimulus triggers an action potential if it surpasses the threshold.
Action potentials are propagated along the axon via sequential depolarizations, ensuring their transmission throughout the body.

Synapses

Synapses are the junctions between neurons or between neurons and effectors.
Most synapses are chemical, transmitting signals via neurotransmitters.
Electrical synapses transmit signals directly via ion flow through gap junctions.

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Description

This quiz covers the fundamental concepts of the nervous system, including the structure and function of neurons, divisions of the nervous system, and the characteristics of neurotransmitters. Students will also explore action potentials, synaptic transmission, and the differences between neural pathways and reflex arcs. Test your knowledge on the essential functions and structures crucial to the nervous system.