How does a microprocessor-controlled prosthetic knee work?

Sensors measure the knee's angle and the forces on it many times a second. A microprocessor adjusts the resistance of the joint to suit walking, stairs or slopes.

How does a myoelectric prosthetic arm work?

Electrodes on the skin of the remaining limb detect electrical signals from muscle contractions. Motors in the prosthetic hand open and close in response.

Why is the socket fit of a prosthetic limb so important?

The socket joins the prosthesis to the body and carries its load. A poor fit causes pain, skin damage and poor control.

CCEA A-Level Life and Health Sciences 0008

Experimental Techniques

Topic overview Standard solutions, titrations and qualitative tests Rates of reaction and organic preparations Physics measurements: oscillations, resistivity, lenses and critical angle Biological tests, colorimetry, chromatography and osmosis

Human Body Systems

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Material ScienceDouble Award

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Medicine, Drugs and Clinical TrialsDouble Award

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Genetics, Stem Cell Research and CloningA2 option

Topic overview DNA structure and the evidence for the double helix RNA, genes and the triplet code Genotype, phenotype and monohybrid inheritance Dihybrid crosses, epistasis and the chi-squared test DNA replication and the Meselson–Stahl experiment Meiosis and genetic variation Insulin, factor VIII and chymosin from genetically modified microbes Recombinant DNA technology and gene cloning Genetic engineering, food supply and ethics Gene therapy and cystic fibrosis Genetic disease, screening and counselling Genetic fingerprinting and gel electrophoresis Stem cells, therapeutic cloning and their ethics

MicrobiologyDouble Award

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Oral Health and DentistryDouble Award

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Analytical Chemistry TechniquesDouble Award

Topic overview Volumetric analysis in industry and healthcare Applied titrations of vinegar, indigestion tablets and bleach Redox titration of iron tablets and evaluating titrations Principles of colorimetry Colorimetric analysis of copper ore, aspirin and iron Thin-layer chromatography and its uses Visualising chromatograms and identifying painkillers and pigments Calorimetry and combustion Molar enthalpy and bond energy calculations Qualitative tests for cations and gases

Enabling TechnologyDouble Award

Topic overview ECG and EEG machines in patient monitoring Ultrasound and IVF equipment in fertility treatment Prosthetic limbs, hearing aids and cochlear implants Workflow and equipment in a medical laboratory Ongoing monitoring of a long-term condition Health data collection, databases and data protection

Enabling Technology

Prosthetic limbs, hearing aids and cochlear implants

3 things to know
A2 10

Overview

Early and modern artificial limbs, carbon fibre, microprocessor knees and myoelectric arms, socket fit and 3D printing, how hearing aids work, digital aids and cochlear implants.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

What is a prosthesis?

Key term

What were early artificial limbs made from, and what were their drawbacks?

Key term

Why is carbon fibre used in modern prosthetic limbs?

Questions from this subtopic

Each one with the model answer underneath.

1
What is a prosthesis?
Model answer
A prosthesis is an artificial device that replaces a missing body part. Artificial limbs and hearing aids restore function lost through injury, illness or a condition present from birth.
2
What were early artificial limbs made from, and what were their drawbacks?
Model answer
Early artificial limbs were made of wood, leather and metal. Early limbs were heavy, uncomfortable and allowed only simple movements.
3
Why is carbon fibre used in modern prosthetic limbs?
Model answer
Carbon fibre is very strong and light. Carbon fibre blades also store and return energy like a spring, helping the wearer walk and run.
4
How does a microprocessor-controlled prosthetic knee work?
Model answer
Sensors measure the knee's angle and the forces on it many times a second. A microprocessor adjusts the resistance of the joint to suit walking, stairs or slopes.
5
How does a myoelectric prosthetic arm work?
Model answer
Electrodes on the skin of the remaining limb detect electrical signals from muscle contractions. Motors in the prosthetic hand open and close in response.
6
Why is the socket fit of a prosthetic limb so important?
Model answer
The socket joins the prosthesis to the body and carries its load. A poor fit causes pain, skin damage and poor control.

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