Ch 12Basic Medical Instruments and Techniques — Class 11 Zoology, concept-first.

Doctors have traditionally relied on a handful of simple, hand-held instruments — the thermometer, stethoscope and sphygmomanometer — to check a patient's basic health quickly and without any invasive…

The stethoscope is a medical device used to listen to internal body sounds - the beating of the heart, the movement of air in and out of the lungs, gut sounds from the stomach and intestines, and even…

The sphygmomanometer, commonly called a blood pressure meter, monitor or gauge, measures blood pressure using an inflatable rubber cuff wrapped around the upper arm, connected to a pressure-measuring…

A glucometer is a small, portable, battery-operated digital meter used to give a quick approximate reading of blood glucose (blood sugar) level.

An autoanalyser is a computer-controlled laboratory instrument built to carry out rapid, automated estimation of many biochemical parameters in a body-fluid sample - common examples include glucose, u…

Alongside instruments used inside a clinic, a growing category of wearable healthcare devices now lets people track several physiological signals continuously in everyday life.

Where the instruments in the previous section listen to or sample the body directly, imaging instruments let a clinician actually see inside a living patient without surgery.

An EEG (electroencephalogram) is a test that evaluates the brain's electrical activity. Brain cells communicate with one another through tiny electrical impulses, and an EEG tracks and records the res…

Radiography (X-ray imaging) uses X-rays - a form of electromagnetic radiation produced inside an X-ray tube - to visualise the internal structures of the body.

Ultrasound imaging uses sound waves pitched far beyond the range of human hearing. These waves are generated by the piezoelectric effect: when an electric potential is applied to certain crystals - le…

Computed tomography, originally called computed axial tomography (CAT or CT scan), takes its name from the Greek words 'tomos' (a slice) and 'graphe' (to write) - literally, a picture built from slice…

Magnetic resonance imaging (MRI), also referred to as NMRI, is a non-invasive test physicians use to diagnose medical conditions without exposing the patient to ionising radiation, unlike conventional…

Positron emission tomography (PET) is a nuclear-medicine imaging technique, and like CT it produces a computerised image, but unlike CT it images function rather than just structure.

Beyond identifying what is wrong, medicine also needs instruments that actively treat disease. Therapeutic instruments described here - the implantable pacemaker and the medical laser - work by direct…

A pacemaker is a medical device implanted to regulate the beating of the heart. It works by using electrical impulses delivered through electrodes to make the heart muscle contract in a controlled, re…

Medical lasers are devices that emit a single, coherent wavelength of electromagnetic radiation, used clinically to cut, coagulate or ablate (destroy) tissue for a range of procedures.

Alongside the instruments used to examine a patient directly, a haematology laboratory relies on a set of standard hands-on techniques for studying the cellular components of blood itself.

A haemocytometer is a thick, specially ruled glass slide used to count blood cells directly under a microscope.

Examining a peripheral dry blood smear under the microscope is an important, simple laboratory test because it lets a technician estimate the approximate number of the different cellular components of…

The differential WBC count is the laboratory method used to determine the relative proportion of each type of white blood cell present in the blood, by carefully examining a well-stained peripheral bl…

This closing Evaluation exercise draws on every instrument and technique covered in the chapter. It opens with seven single-best-answer multiple-choice questions covering the sphygmomanometer, blood s…

Sample papers and previous-year board questions for this subject.