Musculoskeletal & Nervous System Quiz MNB.14

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Questions and Answers

What process converts electrical energy into a chemical signal during neurotransmission?

Chemical synapse dynamics (correct)

Synaptic transmission

Depolarization

Receptor activation

How many different chemicals are known to act as neurotransmitters?

40 (correct)

In a monosynaptic reflex, how many synapses are involved?

Two

Three

Multiple

One (correct)

What type of neuron is most likely to release both small-molecule neurotransmitters and neuropeptides?

Multipolar neurons (C) Signup and view all the answers

What is the main function of postsynaptic receptors in the nervous system?

Bind neurotransmitters and initiate a response (C) Signup and view all the answers

What type of reflex is being described when motor neurons excite antagonistic muscles?

Polysynaptic reflex (C) Signup and view all the answers

In a polysynaptic reflex, which structure is directly responsible for the response in antagonistic muscles?

Motor neuron (C) Signup and view all the answers

Which statement about antagonistic muscles in a polysynaptic reflex is accurate?

One muscle group contracts while the other relaxes. (C) Signup and view all the answers

What role do interneurons play in polysynaptic reflexes?

Connect sensory and motor neurons (B) Signup and view all the answers

Which of the following can be influenced by a polysynaptic reflex?

Both involuntary and voluntary movements (C) Signup and view all the answers

What transmitter is released at the post-ganglionic neuron terminal in the sympathetic nervous system?

Adrenaline (B) Signup and view all the answers

Which cranial nerve is primarily responsible for carrying craniosacral outflow in the parasympathetic nervous system?

Vagus nerve (X) (A) Signup and view all the answers

What primarily constitutes the grey matter in the nervous system?

Somata and dendrites of motor and connector neurons (D) Signup and view all the answers

What is one of the main effects of the sympathetic nervous system?

Bronchial relaxation (C) Signup and view all the answers

What is a characteristic of reflex actions?

They have a predictable and automatic response to stimuli (D) Signup and view all the answers

What role do interneurons play in the reflex arc?

They relay stimulus from sensory neurons to motor neurons (D) Signup and view all the answers

What type of neurons originate from the sacral spinal nerves in the parasympathetic nervous system?

Long preganglionic neurons (D) Signup and view all the answers

Which enzyme is responsible for breaking down acetylcholine in the synaptic transmission process?

Acetylcholinesterase (B) Signup and view all the answers

How is a monosynaptic reflex defined?

Contains only one sensory neuron and one motor neuron (A) Signup and view all the answers

Which statement accurately describes the flow of impulses in the reflex arc?

Afferent nerve fibers carry impulses toward the spinal cord (D) Signup and view all the answers

How do the sympathetic and parasympathetic nervous systems generally interact with each other?

They are antagonistic towards each other. (A) Signup and view all the answers

Where does the impulse continue after the dorsal root ganglion in the reflex arc?

Into the grey matter of the spinal cord (A) Signup and view all the answers

What happens to the degradation products of acetylcholine after it is broken down?

They are taken into the pre-synapse for rebuilding into acetylcholine. (D) Signup and view all the answers

Which of the following is a factor that can determine whether a reflex arc is monosynaptic or polysynaptic?

Presence of interneurons in the circuit (C) Signup and view all the answers

What structure protects the spinal cord within the vertebral canal?

Neural arches of the vertebrae (C) Signup and view all the answers

What happens when the motor neurons stimulate the effector organs during a reflex action?

A desired reflex reaction is produced (D) Signup and view all the answers

Which neurotransmitter is primarily associated with excitatory effects in the parasympathetic nervous system?

Acetylcholine (C) Signup and view all the answers

What type of neuron runs from the spinal cord to the ganglion in the autonomic nervous system?

Pre-ganglionic neuron (D) Signup and view all the answers

What is the primary function of Noradrenaline in the nervous system?

Excitatory neurotransmission (C) Signup and view all the answers

Which receptor type is associated with GABA?

GABAA and GABAB receptors (A) Signup and view all the answers

Which of the following is NOT a division of the peripheral nervous system?

Central nervous system (B) Signup and view all the answers

In the sympathetic nervous system, what type of chain ganglia is primarily utilized?

Paravertebral ganglia (A) Signup and view all the answers

Which part of the spinal cord is generally associated with the sympathetic nervous system?

Thoracolumbar region (A) Signup and view all the answers

Which system is responsible for involuntary control of body functions?

Autonomic nervous system (C) Signup and view all the answers

Which type of neuron is involved in transmitting signals towards the central nervous system?

Afferent neuron (B) Signup and view all the answers

What effect does dopamine primarily have in the nervous system?

Regulates mood and motivation (B), Inhibitory (C) Signup and view all the answers

What indicates the pathway of a monosynaptic reflex?

Sensory neuron activates a motor neuron directly. (A) Signup and view all the answers

In the context of reflexes, what role do inhibitory interneurons play?

They inhibit the activity of motor neurons. (D) Signup and view all the answers

What triggers the tendon reflex mechanism?

Excess muscle contraction. (A) Signup and view all the answers

Which of the following statements about the spinal cord's role in reflexes is correct?

The spinal cord integrates sensory and motor neural activity. (B) Signup and view all the answers

What is the primary purpose of the feedback mechanism in muscle reflexes?

Causing muscle relaxation during excessive tension. (A) Signup and view all the answers

What occurs during the tendon reflex?

Muscle tension leads to inhibition of the motor neuron. (D) Signup and view all the answers

How do sensory receptors contribute to muscle reflexes?

They detect changes in tendon tension. (B) Signup and view all the answers

Which structure is primarily involved in the reflex arc?

Motor and sensory neurons. (D) Signup and view all the answers

What is the result of activating the motor neuron in a reflex reaction?

Excitation of the primary muscle occurs. (D) Signup and view all the answers

What is the relationship between sensory neurons and motor neurons in a reflex arc?

Sensory neurons stimulate the motor neurons to produce a response. (C) Signup and view all the answers

Study Notes

Musculoskeletal System, Nervous System & Bioelectricity, MNB.14

The lecture covers the musculoskeletal system, nervous system, and bioelectricity, specifically focusing on the peripheral nervous system and reflexes.
The presenter is Professor Warren Thomas.
The date of the lecture is November 26, 2024.

Learning Outcomes

Learners will be able to describe the effects of neurotransmitters on various bodily systems.
Learners will be able to recall the peripheral nervous system.
Learners will be able to describe the structure of the spinal cord and its connection to the somatic nervous system.
Learners will be able to outline the operation of the reflex arc.
Learners will be able to differentiate between monosynaptic and polysynaptic reflexes.

Chemical Synapse

The sequence of events converts electrical energy (action potential) to a chemical signal (neurotransmitter) and back to electrical energy.
In the Autonomic Nervous System (ANS), this can involve neuron-neuron communication (at ganglia) or neuron-target tissue interaction.
Key components of chemical synapses include synaptic vesicles, neurotransmitters, receptors in the plasma membrane of the postsynaptic neuron, and the synaptic cleft.

Neurotransmitters

Approximately 40 different chemicals act as neurotransmitters.
Each neuron typically releases only one small-molecule neurotransmitter.
A neuron may also release one or more neuropeptides concurrently.
Postsynaptic neurons often have receptors for multiple neurotransmitters, which can be excitatory or inhibitory.
Examples of neurotransmitters and their abbreviations, locations, receptors, and effects are provided in a table.

Peripheral Nervous System (PNS)

The PNS is divided into the autonomic nervous system (ANS) and somatic nervous system.
The ANS further branches into sympathetic, parasympathetic, and enteric systems.
31 pairs of spinal nerves branch from the spinal cord, with specific locations and names.
The lecture provides details on the anatomy and function of the sympathetic and parasympathetic nervous systems, including how they branch through the body and their function.

Autonomic Nervous System

The Autonomic Nervous System has pre-ganglionic and post-ganglionic neurons.
Pre-ganglionic neurons run from the spinal cord to the ganglion.
Post-ganglionic neurons run from the ganglion to the target organ.

Sympathetic Nervous System

Sympathetic nervous system has a thoracolumbar outflow with short pre-ganglionic and long post-ganglionic neurons.
Neurons connect to paravertebral ganglia on both sides of the spinal column.
The primary neurotransmitter of the SNS is acetylcholine (ACh) at the synapse.
The neurotransmitter at the target tissue is adrenaline.
The effect of the sympathetic system, in a generalized way, is preparation for the "fight or flight" response.

Parasympathetic Nervous System

This system has a craniosacral outflow with long pre-ganglionic and short post-ganglionic neurons.
Ganglions lie close to or within target organs.
The primary neurotransmitter for both pre- and post-ganglionic neurons is Acetylcholine (ACh).

Spinal cord

The spinal cord functions as a transmitter of nerve impulses and a reflex center.
Anatomically, the spinal cord is protected by the vertebrae and lies within the vertebral canal.
The histology of the spinal cord distinguishes between grey matter, and white matter.
Grey matter comprises cell bodies and dendrites of motor and interneurons, along with neuroglial cells and blood vessels.
White matter contains bundles of axons and dendrites.
The spinal cord is divided into 4 regions: Cervical (neck), Thoracic (chest/upper back), Lumbar (lower back), and Sacral (base of spine).

Spinal Reflexes

Reflex actions are automatic responses to stimuli that do not require conscious thought.
Reflex actions involve sensory neurons, interneurons, and motor neurons.

Reflex Arc

Receptor cells pick up stimuli and carry it towards the spinal cord through sensory neurons and long afferent somatic nerve fibers.
The sensory neurons synapse with interneurons in the greay matter.
In the grey matte, the interneurons synapse with the efferent/motor neurons.
The efferent/motor neuron carries the signal to the effector organ.
Details on various components of the reflex arc are included along with specifics regarding monosynaptic and polysynaptic reflexes.

Monosynaptic vs Polysynaptic Reflexes

Monosynaptic reflexes involve direct connection between sensory and motor neurons.
Polysynaptic reflexes utilize interneurons, facilitating more complex responses.

Stretch Reflex

This reflex results in muscle contraction in response to stretching.
It is a monosynaptic reflex. The reflex arc starts at the receptor and then travels to the spinal cord where it will synapse with the effector muscles causing it to contract. This is involved in the patella tap in your knee.

Tendon Reflex

This reflex relaxes muscles to prevent tendon rupture from excessive tension
It is a polysynaptic reflex.

Summary

The lecture covers a comprehensive overview of the peripheral nervous system.
Neurotransmitters control various bodily systems, while the peripheral nervous system and its two branches — the autonomic and somatic nervous systems — are critical for functionality.
Reflex responses, including stretch and tendon reflexes, are essential in regulating muscle tension.

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Description

This quiz examines the key concepts related to the musculoskeletal system, nervous system, and bioelectricity with a special focus on the peripheral nervous system and reflex mechanisms. Participants will test their knowledge on neurotransmitters, spinal cord structure, and the reflex arc, including the differences between monosynaptic and polysynaptic reflexes.