Medicine Flashcards
Explain infectious diseases
- Infectious diseases develop when pathogens such as bacteria and viruses invade the body. They are a leading cause of death, particularly in developing countries.
- Some bacterial infections are beneficial, helping to break down food in our guts during digestion. But harmful bacteria can cause diseases by a variety of mechanisms, including sticking to healthy cells and gumming up their surfaces, and producing toxic chemicals.
- Fungi can cause diseases such as athlete’s foot, while other pathogens include single-celled parasites such as Plasmodium that can cause malaria.
- Many multicellular parasites also cause disease, including tapeworms that can grow several yards long in intestines.
- Some rare infectious diseases are caused by prions, proteins that have folded into the wrong shape and convert other proteins to the faulty state.
Prion diseases destroy the brain, and include bovine spongiform encephalopathy (BSE or “mad cow disease”) in cattle, which can be passed on to people through the food chain as Creutzfeldt–Jakob disease (CJD).
What is Cardiovascular disease
- Cardiovascular disease is a spectrum of disorders that affect the heart and blood vessels, including heart attacks and stroke. It is the leading cause of death in developed nations.
- Heart attacks occur when a blood clot suddenly blocks an artery in heart muscle. It can cut off most or all of the blood supply to the heart, so heart cells that don’t receive enough oxygen-rich blood begin to die.
This is often fatal unless a patient receives prompt treatment to restore blood flow.
- Strokes occur when the blood supply to part of the brain is cut off and brain cells begin to die, leading to brain damage and possibly death.
- Most strokes are ischemic ones, in which a blood clot blocks the blood supply. In hemorrhagic strokes, brain damage occurs when a weakened blood vessel bursts.
- The best way to prevent cardiovascular disease is to avoid eating a lot of fatty food, which can make fatty plaques build up in the arteries. High blood pressure and cholesterol, smoking, and lack of exercise are also risk factors.
Explain Cancer
- Cancers are diseases that develop when cells in the body divide uncontrollably to form lumps called tumors.
- There are more than two hundred types of cancer, and it is the second most common cause of death in developed countries after cardiovascular disease.
- Tumors can be “benign” lumps that are harmless, but cancer is a term for “malignant” tumors with the ability to spread to other parts of the body, either by invading surrounding tissues or by migrating to other organs through the blood or lymphatic system.
- “Metastasis” occurs when cancer cells reach a new area and continue dividing to create new tumors.
- Treatments include surgery to remove malignant tumors and radiotherapy, which destroys them using radiation.
In chemotherapy, patients take drugs that target rapidly dividing cells, although this has unpleasant side effects because it also harms healthy cells that normally divide rapidly, including hair follicles.
Sometimes, chemicals naturally produced by the body’s immune system can shrink tumors with fewer side effects.
What are Drugs
- In general, a drug is any chemical that alters normal body function. Usually, it refers to a chemical designed to treat, cure, or prevent disease, or enhance physical or mental health.
- Drugs fall into a vast number of classes, including antibiotics that kill bacteria without harming body cells and antiviral drugs that sabotage virus replication strategies.
- The world’s best-selling drug, Lipitor, lowers cholesterol levels, while other top-selling drugs treat asthma and cardiovascular disease.
Analgesics are drugs that relieve pain.
- Injuries make nerve endings send signals to the brain that trigger pain sensations, and analgesics interfere with these signals in the nervous system anywhere from the injury site to the brain itself.
- Many painkillers come from naturally occurring chemicals. Aspirin uses a chemical in willow bark, for instance, while opiates work in a similar way to opium, derived from poppies.
- Sometimes, people use recreational drugs such as opioids or hallucinogens for their perceived beneficial effects on mood or perception, but many of these are highly addictive.
Explain IVF
A method of assisted conception, IN-VITRO FERTILISATION brings sperm and egg together outside the body. If embryos successfully develop, usually one to three of them are implanted into the woman’s uterus
- In vitro fertilization, or IVF, is a technique that allows some infertile women to become pregnant. Doctors might recommend it if a woman has damage to her fallopian tubes or if her partner has a low sperm count.
- During the IVF process, the woman usually takes drugs to boost the numbers of mature eggs in her ovaries. Then doctors remove the eggs, usually by guiding a needle into the ovaries monitored by an ultrasound scanner. The eggs are mixed with sperm and cultured in the lab.
- If embryos successfully develop, usually one to three of them are implanted into the woman’s uterus. More embryos means a higher chance of a successful pregnancy, but many countries have guidelines or laws that restrict the number of embryos used because of the risks of multiple pregnancies, which often lead to premature birth.
- Typically, only about a quarter to a third of women become pregnant after one IVF attempt, although the chance of success is highly dependent on the woman’s age.
Explain Kidney dialysis
- Kidney dialysis is a treatment for people who have poor kidney function, usually as a knock-on effect of diabetes or uncontrolled high blood pressure, or due to inflammation.
- Dialysis carries out key kidney functions by filtering blood to remove waste, salt, and excess water.
- In hemodialysis, blood is drawn out from an artery and pumped into a dialysis unit. Inside the unit, waste products in the blood pass into a fluid called the dialysate through holes in a membrane that are too small to admit blood cells. The cleaned blood is then returned into a vein. Typically, hemodialysis treatments take place three times a week and last about three or four hours.
- In peritoneal dialysis, blood is cleaned inside the body with the lining of the abdominal cavity acting as the membrane. Dialysate is flowed into the abdomen through a permanent tube and then extracted after the fluid has absorbed waste products and excess water from arteries and veins that line the peritoneal cavity.
Explain Surgery
- Surgery is a medical procedure to manually remove or modify tissue in the body, usually to treat disease.
- Surgical operations began at least seven thousand years ago, when Stone Age people used flint tools to cut open skulls, possibly to treat head injuries or for other perceived health benefits.
- Modern surgery takes place in operating rooms with carefully sterilized surgical instruments. Patients are given local anesthetics that numb the part of the body surgeons will operate on, or general anesthetics that make them unconscious.
- Common surgical operations include caesarean sections to deliver babies through the abdomen and repairs of hernias (which usually involve part of the intestine protruding through a hole or weakness in the wall of the abdomen).
- In laparoscopic, or “keyhole,” surgery, surgeons make tiny incisions in the body and perform surgery guided by a miniature camera attached to a long surgical instrument.
Keyhole surgery is often used to remove the gall bladder. The smaller incision means less pain, scarring, and risk of infection.
Explain Blood transfusion
- Blood transfusions involve taking blood from one person—a donor—and giving it to another person.
- Patients sometimes need transfusions after losing blood due to injury, during operations, or in childbirth, or because they have a disease that stops them producing enough red blood cells.
- Usually, collected blood is mixed with an anticoagulant as it drains from a catheter in the donor’s vein into a plastic bag.
Tests determine the donor’s blood type, because it has to be compatible with the recipient’s blood type, otherwise the patient’s immune system will reject it.
Blood types have four genetic categories: A, B, AB, and O. About 40 percent of the population are “universal donors” with O-type blood, which is safe for anyone to receive.
Patients with an AB blood type are “universal recipients,” who can safely receive any type of blood.
The blood is also screened for infectious agents including HIV (human immunodeficiency virus) and then ideally separated into its three main components—red blood cells, plasma, and platelets—to make best use of it for patients’ individual needs.
Explain Laser therapy
- In laser surgery, surgeons use a laser to cut or remove tissue instead of a scalpel. They sometimes use lasers to make incisions for otherwise conventional surgery, or to vaporize unhealthy tissues that have high water content.
- Lasers are sometimes used in cosmetic surgery to destroy the outer skin on the face, to stimulate the growth of new skin that is softer and less wrinkly or scarred.
- Laser surgery is commonly used on the eye. Doctors use a laser to vaporize part of the cornea in order to change its shape and correct shortsightedness (myopia) or farsightedness (hyperopia).
- Green lasers are often used to shrink enlarged prostate glands in men, with the green light being highly absorbed by the red prostate tissue.
- Dentists are increasingly using lasers to replace dental drills for almost painlessly removing decayed parts of teeth, as well as speeding up the bleaching process to whiten teeth.
A huge benefit of laser surgery is that there’s no physical contact with a surgical instrument, reducing the risk of infection.
Gene therapy
- Gene therapy is a technique for treating diseases caused by defective genes in DNA that produce faulty proteins. So far, this treatment is still in an early experimental stage.
- In gene therapy, scientists usually alter a virus genetically to carry a section of normal human DNA. They exploit the fact that some viruses incorporate their own DNA into the human genome as part of their replication strategies.
So scientists can dupe a virus into adding a normal gene to human DNA to replace a dysfunctional one.
The genetically engineered virus targets cells such as lung or liver cells, then introduces the therapeutic human gene, which starts manufacturing the necessary proteins to restore the cells to a healthy state.
Scientists hope this technique could permanently cure a diverse range of genetic diseases, including hemophilia, a male-only disease in which the blood lacks the normal clotting factors so that even minor injuries can cause dangerous blood loss. However, so far no human gene therapy has conclusively proved to be effective, permanent and safe.
Explain Stem cell therapy
- Stem cell treatments could one day cure many previously incurable diseases, including multiple sclerosis, paralysis, and Alzheimer’s disease.
- Found in embryos and various adult tissues including bone marrow, stem cells are unique in their ability to differentiate into a wide range of specific cell types that could be used to regenerate and repair damaged tissue.
- Bone marrow transplants are effectively a stem cell treatment for leukemia.
- Adult stem cells are limited in the cell types they can generate, but stem cells from embryos can form any type of cell, including liver cells, neurons, or skin cells.
- Treatments using cells derived from human embryos, including neurons for spinal cord repair, are still in the early trial phase.
Scientists hope it will be possible in the future to take adult stem cells from a patient needing treatment and program them to return to an embryonic-like state.
These pluripotent stem cells could diversify into any tissue the patient needs, without any risk of tissue rejection by the immune system.
