Exam 2 (Biomechanics, Bioinstrumentation, Bioimaging) Flashcards
What is biomechanics?
-The application of principles from classical mechanisms to study the movement of living systems
-The analysis of how different body parts work together
How do you write F as a vector?
-F (with arrow thing on top)
-Picture 2D and 3D representations of vector F
Kinetics
Only deals with forces that cause motion (force, torque, power, work)
Kinematics
Deals with objects solely in terms of their position, velocity, or acceleration (time, position, displacement, velocity, acceleration)
Vector Addition
C = A + B = B + A = ↗
Vector Subtraction
C = A - B = (-1)B + A = ↘
Dot Products
-Dot product of vectors produces a scalar
-Unit times itself = 1
-Unit times another unit = 0
-Use dot as multiplication sign
-i times i, j times j, k times k (add every term together)
Cross Products
-Cross product of vectors is a vector that points along the axis of rotation, the z-axis coming out of the page
-Unit times itself = 0
-i x j = k, j x k = i, k x i = j, i x k = -j, j x i = -k, k x j = -i
-Use cross as multiplication sign
-i times i, j, k, j times i, j, k, k times i, j, k (add every term together)
Unit Vector eF
eF = (Fxi + Fyj + Fak) / (sqrt(Fx^2 + Fy^2 + Fz^2))
Static Equilibrium
-Net force = 0
-Net torque = 0
-Torque = F times r times sin (angle between F and lever arm)
Axial Stress
σ = F / A (A is cross sectional area)
Max Sheer Stress
Tmax = F45° / A45° = 0.5σ
Strain
ε =Δl / l
Elastic Modulus
E = σ / ε
What is bioinstrumentation?
-The application of electronics and measurement principles to develop devices to diagnose and treat diseases
What are the common components of a measurement system?
-Sensor
-Processor
-Receiver
Sensor
Detects the physiological parameter and converts the input parameter into a signal
Processor
Modifies the received signal and filters unwanted info ( also compared to previous signals)
Receiver
Displays, stores, or communicates signal in an interpretable way
What are the different types of sensors?
-Thermal (thermocouple, thermistor)
-Mechanical (strain gauge, piezoelectric)
-Electrical (electrode)
-Chemical (electrode)
-Optical (photodiode, photomultiplier)
Thermocouple
-2 dissimilar metals are fused to produce 2 junctions
-Records voltage difference
Thermistor
-Homogeneous composites of dissimilar metals
-Records resistance difference
Rt =
Roe^B(1/T - 1/To)
Mechanical sensors measure…
Force, pressure, and strain
Strain Gauge
-Sensor whose resistance varies with applied force
-Sensing element is piezoelectric materials
Electrodes
-Often used to detect the electric potential generated by cellular ionic currents
-Range from micro-sized probes to larger adhesive pads
Action Potential
-All cells have resting potential caused by difference in ion concentrations
-Action potential is the electric potential generated by cell membrane
EGG measures…
Electrical activity of cardiac muscle
EEG measures…
Electrical activity of the brain
Resting Potential Cycle
(1) Resting potential → (2) depolarization → (3) repolarization → (4) resting potential
Chemical sensors measure…
The presence and concentration of specific chemicals
Ion Selective Electrode (ISE)
ISE’s acquire specificity from membranes that are permeable to particular ion species
A working cell consists of…
ISE, reference electrode, and voltmeter sensors
Potentiometric Sensor
Sensors that produce a potential or voltage that is proportional to ion concentration
Amperometric Sensor
A sensor in which current is proportional to the concentration of the pieces generating the current
Optical sensors are able to detect…
Visible, infrared, and ultraviolet light
Photoides
-Light sensitive semiconductor diode
-Produces a current if it absorbs photons
-Made of semiconductor materials like Silicon
Photomultipler
-Amplifies weak light signals through a series of processes involving a photocathode, dynode, and anode
-Offer high sensitivity
Ohm’s Law
i = Δv/R or ΔV = iR
(ΔV = potential difference or voltage drop across ideal conductor)
(i = current (amp))
R = (resistance of conductor)
