Medical Technology Bionics

Differences between biocompatibility, biomaterials and biomedical devices

Syllabus Point 1: Maintaining Humans as Functional OrganismsSyllabus Point 2: Beating of the heart and continuity of blood flowValves: Allow blood to flow in one direction (forward)Atria: Upper Chamber Receives BloodVentricles: Lower Chamber Pumps blood back to lungs and bodyMajor Arteries and Veins: Carries blood around the body Vena Cava = Vein from the body Aorta = Largest artery in the body

Electrical signals and rhythmic contractions: Group of special cells found in the RA are connected to the atrio ventricular node which initiates electrical signals to the heart to stimulate beats. Contractions of the heart are controlled electrically Metal electrodes are attached to the skin on a persons arm, legs and chest Electrodes detect the electrical activity and record it on moving paper Electrocardiogram allows doctors to evaluate heart problems.

The P-Wave is produced by the electrical signals that cause the atria to contract The QRS Wave represents the signals that bring about the contraction of the ventricles The T-Wave represents the recovery wave Lub Loud first sound due to valves between atria and ventricles closing Dub Second sound due to valves in arteries closing

Pacemaker:

Properties of materials that make them versatile for making artificial body parts:

Treatment for Heart Problems:

Syllabus Point 3: Replacement of damaged body structures

Support: Bones of our skeleton are very light yet also very strong S-Shaped structure of backbone makes it possible for us to stand upright.Protection: Bones protect the soft organs of our body from damage Skull = Brain, Ribcage = Heart, Backbone = Spinal NervesMovement: Muscles Attach to our bones to provide our bodies with movement Muscles contract and relax to help us walk, run and jumpStorage: Bones can be spongy or compact in structure and hold inside them minerals like calcium and phosphorus Calcium in the bones make them strong and hardProduction of Blood Cells: Bone marrow, the soft jelly-like tissue filling the spaces within bones, is responsible for producing red blood cells, some white and some platelets

Types of Joints:

Silicone can be used to coat the end of small bones in a joint where the cartilage has been destroyed. Silicone can withstand low forces in small joints but not large forces in large joints. (Good for fingers and toes)

UHMWPE (Ultra High Molecular Weight Polyethylene): Long chain of CH2 Resistant to abrasion, strong, doesnt deform easily and has good strength towards fatigue Suitable alternative to cartilage because it is compatible with surrounding tissues The bone like components of an artificial joint must be strong and durable but not too heavy Superalloy Mixture of suitable metals that combine to form a metal with a greater strength than one metal alone (Usually titanium alloys and Cobalt-Chromium Molybdenum) Best materials for placing the bone components of a large joint will be characterised by: High Strength Low Weight Good Compatibility with body tissue InertnessCementation of Artificial Joints: Artificial joints are either fixed in place using a cement or by a cementless system which stimulates bone tissue to grow into the implant Cemented joints rely on a fixing agent to secure the superalloy structure into place Uncemented joints may also be used in hip replacement The Cementless hip replacement is considered to last longer than a cemented one and is therefore more commonly used in younger patients.Syllabus Point 4: Life Support SystemsResuscitation: Cells without oxygen begin to die as CO2 is toxic If the heart ceases to pump, the oxygen vital to the body will not be distributed Artificial response is called resuscitation The resuscitation is called CPR (Cardio-Pulmonary Resuscitation) This procedure can temporary maintain a persons life Two techniques = Mouth to Mouth or Heart CompressionsHeart-Lung Machines: Carry out the function of a normal heart and lung in a mechanical way Pumps are used to move the blood around the body Artificial lungs remove the waste products from the blood and replace it with oxygen needed for cell health and respiration Blood flows into an oxygenator Body remains oxygenated whilst the heart or lung are stopped/removed from the body throughout the operationLife Support Systems: Mechanically sustain a persons life Ventilators have built in monitoring devices which measure the volume of Carbon Dioxide in exhaled air Ventilation machines are equipped with alarm systems. They warn the medical staff of any malfunction or emergency and are essential to a ventilated patients health

Other Life Support Systems:

Syllabus Point 5: Non-Invasive / Minimally Invasive Techniques Time taken in healing can result in expensive hospital costs, loss of body tone and fitness, serious rate of infection and general weakness. Doctors are constantly looking to avoid such invasive surgery Non-Invasive techniques do not penetrate the skin and can identify injury, disease or malfunctionMinimally Invasive Technology: To lower risk of infection and reduce trauma, traditional open surgical techniques are being replaced by minimally invasive techniques. Best known as Keyhole Surgery Endoscopes are used to view inside the body and image is shown on a TV Screen and also has scissors to take samples Disadvantages = Expensive and not all surgeries are possibleNon-Invasive Diagnostic Techniques: