Cellular Physiology of Muscle Fiber

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Questions and Answers

What initiates the wave-like motion that produces an action potential in muscle fibers?

Binding of calcium to troponin

Release of calcium from the sarcoplasmic reticulum

Elevation of intracellular calcium concentration

Influx and efflux of ions across muscle fibers (correct)

What is the characteristic shape of a normal Motor Unit Action Potential (MUAP)?

Monophasic with a single peak

Triphasic with larger first and second peaks (correct)

Quadriphasic with alternating peaks

Biphasic with equal peaks

How does the distance from the surface electrodes affect the EMG signal?

It reverses the waveform direction

It has no effect on the EMG signal

It causes attenuation of the signal (correct)

It increases the intensity of the signal

Which intracellular event leads to muscle fiber contraction?

Actin-myosin cross-bridging Signup and view all the answers

What happens to the action potential as it propagates along muscle fibers?

It becomes superimposed in surface EMG Signup and view all the answers

What does the innervation zone (IZ) represent in muscle physiology?

The location where action potentials are initiated Signup and view all the answers

What is the source of thermal noise in EEG measurements?

Random thermal motion of charge carriers Signup and view all the answers

What role does calcium play in the contraction of muscle fibers?

It binds to troponin to facilitate cross-bridging Signup and view all the answers

What effect does electrode position have on MUAP measurements?

It can reverse the direction of the waveform Signup and view all the answers

Which type of noise is characterized by a frequency spectrum that decreases with increasing frequency?

Flicker noise Signup and view all the answers

At what frequency does power line interference typically occur?

50/60 Hz Signup and view all the answers

In the context of EEG applications, which monitoring technique is considered non-invasive?

Brain edema monitoring Signup and view all the answers

What is a distinguishing characteristic of EEG readings in normal people compared to those with brain edema?

Normal EEG around 5 Hz, brain edema around 10 Hz Signup and view all the answers

What deep learning framework is utilized for detecting Parkinson's disease via EEG signals?

Feature extraction combined with LSTM networks Signup and view all the answers

What can saturate the amplifier in EEG systems?

Electrode offset voltage Signup and view all the answers

Which of the following is NOT a type of interference affecting EEG measurements?

Nerve signal interference Signup and view all the answers

What is the primary function of the heart's ventricles?

To pump blood into the circulatory system Signup and view all the answers

Which phase of the heart cycle is characterized by the filling of the heart with blood?

Diastole Signup and view all the answers

What is the role of the specialized conduction system within the heart?

To initiate and coordinate electrical events Signup and view all the answers

Which components are typically part of an ECG acquisition system?

Electrodes, amplifiers, and filters Signup and view all the answers

In terms of the heart's anatomy, which chambers act as storage for blood?

Atria Signup and view all the answers

What electrical activity is crucial for the rhythmic contraction of the heart's atria and ventricles?

Conduction of action potentials Signup and view all the answers

What is the role of amplifiers in an ECG system?

To enhance the electrical signals from the heart Signup and view all the answers

Which component of the ECG system is responsible for capturing the electrical signals from the heart?

Electrodes Signup and view all the answers

What type of muscle pairs are typically used to control one degree of freedom in myoelectric prostheses?

One agonist and one antagonist muscle Signup and view all the answers

Which technique is used to identify different intended movements in pattern recognition-based prosthesis control?

Pattern classification Signup and view all the answers

Which of the following is NOT an emerging neural-machine interface technique for neuroprosthesis control?

Cognitive behavioral therapy (CBT) Signup and view all the answers

What is one of the primary differences between muscle stimulators and myoelectric sensors?

Incorporation of stimulating analog circuits Signup and view all the answers

Why are larger electrodes used in muscle stimulators?

To prevent burns and dissipate electricity/heat Signup and view all the answers

What type of electrodes are often used when muscle stimulators utilize surface electrodes?

TENS electrodes Signup and view all the answers

What component is essential to implement movement commands in pattern recognition-based control systems?

A prosthesis controller Signup and view all the answers

What is one characteristic of EMG patterns used for controlling prostheses?

They can change based on user intent. Signup and view all the answers

What does temporal resolution refer to in the context of image acquisition?

The time taken to acquire and the time between images Signup and view all the answers

How is radiometric resolution typically expressed?

In bits, representing possible intensity values Signup and view all the answers

Why are wavelengths greater than 100 or 200 pm not ideal for medical applications?

They are absorbed completely by the body. Signup and view all the answers

Which statement accurately describes the measurement of absorbed radiation?

It can determine how much radiation is absorbed by each body part. Signup and view all the answers

What does an increase in bits in radiometric resolution indicate?

An increase in the number of possible intensity values. Signup and view all the answers

Which imaging method utilizes ionizing radiation?

X-Ray Signup and view all the answers

Which factor does NOT affect the image acquisition process?

The color of the object being imaged. Signup and view all the answers

In terms of colour resolution, how many values can an 8-bit pixel represent?

256 possible values Signup and view all the answers

Study Notes

Cellular Physiology of the Muscle Fiber

Muscle fiber contraction is triggered by electrical potential changes in the extracellular fluid surrounding the muscle fibers.
This change is caused by ion influx and efflux across numerous muscle fibers.
The exchange of ions occurs in a wave-like motion, producing an action potential.
The action potential triggers the release of calcium from the sarcoplasmic reticulum into the intracellular environment.
Calcium binds to troponin, leading to actin-myosin cross-bridging and muscle fiber contraction.

Motor Unit Potential (MUAP)

The MUAP is the theoretical waveform of an action potential measured using a surface electrode.
The action potential from the innervation zone (IZ) propagates bilaterally along the muscle fibers.
The waveform direction reverses depending on the electrode's location relative to the IZ.
A normal MUAP is triphasic with larger first and second-phase peaks and a smaller third-phase peak.

EMG Signal

The theoretical EMG signal represents action potentials propagated along muscle fibers.
Action potentials are attenuated based on the distance between muscle fibers and surface electrodes.
These attenuated action potentials are superimposed in surface EMG.

Electrocardiogram (ECG) Basics

The heart is a four-chambered pump for the circulatory system.
Ventricles are responsible for the heart's pumping function.
Atria store blood during ventricle pumping.
Diastole is the heart's filling/resting phase.
Systole is the heart's pumping phase.
A coordinated series of electrical activities within the heart facilitates rhythmic contraction of atria and ventricles.
These electrical activities are initiated by a synchronized series of events within the specialized conduction system of the heart.
Non-ideal factors in EEG measurements include thermal noise, flicker noise, power line interference, and electrode offset voltage.

EEG Acquisition System

The EEG acquisition system consists of electrodes, amplifiers, and filters.

EEG Application

EEG can be used for brain disease detection, such as brain edema and Parkinson's disease.

EMG Application

EMG applications include myoelectric prostheses, pattern recognition-based prosthetic control, and neuro control prosthesis.
Neuro control prosthesis techniques include targeted muscle reinnervation (TMR), brain computer interface (BCI), and peripheral nerve interface (PNI).

Muscle Simulators

Muscle simulators utilize similar principles to myoelectric sensors but with larger electrodes, a stimulating analog circuit, and higher power delivery requirements.

Temporal Resolution in Medical Imaging

Temporal resolution refers to the time taken to acquire an image or the time between images.
Image capture is not instantaneous, and the signal takes time to travel from the body to the detector.

Radiometric/Color/Contrast Resolution in Medical Imaging

This resolution represents the level of variability encoded by each pixel or voxel.
It defines the range of intensity values possible, often expressed in bits.

Image Acquisition Systems

Common image acquisition systems include X-ray, CT, PET, and microscopy.

X-rays

X-rays are electromagnetic radiation with wavelengths between 10 pm-10 nm.
They can be used to image the body because different tissues absorb different amounts of radiation.
The amount of radiation that passes through the body is detected by a detector.

Examples of X-ray Imaging

High density objects (bone) block more X-rays than lower density objects (soft tissue).
Objects of differing thicknesses absorb different amounts of X-rays.

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Description

Explore the intricate processes involved in muscle fiber contraction and the significance of motor unit action potentials. This quiz delves into the physiology behind action potentials, ion exchange, and the role of calcium in muscle dynamics. Enhance your understanding of neuromuscular physiology and related concepts.