Category Zoology

What is pneumonia?

Pneumonia is an infection in one or both lungs. Bacteria, viruses, and fungi cause it.

The infection causes inflammation in the air sacs in your lungs, which are called alveoli. The alveoli fill with fluid or pus, making it difficult to breathe.

Bacteria, viruses, or fungi can cause pneumonia.

Common causes include:

  • Flu viruses
  • Cold viruses
  • RSV virus (the top cause of pneumonia in babies age 1 or younger)
  • Bacteria called Streptococcus pneumoniae and Mycoplasma pneumoniae

Some people who are in the hospital get “ventilator-associated pneumonia” if they got the infection while using a ventilator, a machine that helps you breathe.

If you get pneumonia while you’re in a hospital and aren’t on a ventilator, that’s called “hospital-acquired” pneumonia. But most people get “community-acquired pneumonia,” which means they didn’t get it in a hospital.

 

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What causes asthma?

What we do know is that asthma is a chronic inflammatory disease of the airways. The causes can vary from person to person. Still, one thing is consistent: When airways come into contact with a trigger, they become inflamed, narrow, and fill with mucus.

Allergies with asthma is a common problem. Eighty percent of people with asthma have allergies to things in the air, like tree, grass, and weed pollens, mold, animal dander, dust mites, and cockroach droppings. In one study, children with high levels of cockroach poop in their homes were four times more likely to have childhood asthma than children with low levels. An allergy to dust mites is another common asthma trigger.

For about 80% of people with asthma, a heavy workout can cause airways to narrow. Exercise is often the main asthma trigger. If you have exercise-induced asthma, you will feel chest tightness, cough, and have trouble breathing within the first 5 to 15 minutes of an aerobic workout. For most people these symptoms go away in the next 30 to 60 minutes of exercise. But up to 50% of people with exercise-induced asthma may have another attack 6 to 10 hours later. A slow warm up may help prevent this.

 

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What can emphysema contribute to?

Emphysema is a type of COPD (chronic obstructive pulmonary disease). COPD is a group of lung diseases that make it hard to breathe and get worse over time. The other main type of COPD is chronic bronchitis. Most people with COPD have both emphysema and chronic bronchitis, but how severe each type is can be different from person to person.

Emphysema affects the air sacs in your lungs. Normally, these sacs are elastic or stretchy. When you breathe in, each air sac fills up with air, like a small balloon. When you breathe out, the air sacs deflate, and the air goes out.

In emphysema, the walls between many of the air sacs in the lungs are damaged. This causes the air sacs to lose their shape and become floppy. The damage also can destroy the walls of the air sacs, leading to fewer and larger air sacs instead of many tiny ones. This makes it harder for your lungs to move oxygen in and carbon dioxide out of your body.

The cause of emphysema is usually long-term exposure to irritants that damage your lungs and the airways. In the United States, cigarette smoke is the main cause. Pipe, cigar, and other types of tobacco smoke can also cause emphysema, especially if you inhale them.

Exposure to other inhaled irritants can contribute to emphysema. These include secondhand smoke, air pollution, and chemical fumes or dusts from the environment or workplace.

Rarely, a genetic condition called alpha-1 antitrypsin deficiency can play a role in causing emphysema.

 

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Why does our respiratory system produce sputum (mucus)?

Mucus is secreted from two distinct areas within the lung tissue. In the surface epithelium, which is part of the tissue lining of the airways, there are mucus-producing cells called goblet cells. The connective tissue layer beneath the mucosal epithelium contains seromucous glands which also produce mucus.

The respiratory tract produce about two litres of mucus a day from these glands (Martini, 2003), and this is composed of water, carbohydrates, proteins and lipids. The high water content helps to humidify the passing inspired air. Mucus contains glycoproteins (or mucins) as well as proteins derived from plasma, and products of cell death such as DNA.

Mucus is sticky and this helps to trap dust particles, bacteria and other inhaled debris. Mucus also contains natural antibiotics, which help to destroy bacteria – the epithelial cells secrete a substance called defensis. Mucus also contains lysozyme, which is an antibacterial enzyme. 

 

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Where does the foetus begin to grow?

Once a sperm cell and an egg cell join, the fertilized egg begins to grow inside the woman’s uterus. During pregnancy the female body becomes a complete support system for the unborn baby.

It takes almost nine months for the fertilized egg to become a fully formed baby. Throughout this time, the uterus provides protection and warmth. As the baby develops, the uterus stretches until it is larger than any other organ in the body. The growing foetus shows in the pregnant woman’s “bump” at the front of her abdomen.

Your baby will change a lot throughout a typical pregnancy. This time is divided into three stages, called trimesters. Each trimester is a set of about three months. Your healthcare provider will probably talk to you about your baby’s development in terms of weeks. So, if you are three months pregnancy, you are about 12 weeks.

 

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What happens when sperm meets egg?

Each sperm cell has a head made up of genetic material and a tail that enables speedy swimming. Up to 300 million sperm can be released at one time, and they compete to be first to fertilize the female egg.

Inside a woman’s fallopian tube, her egg is surrounded by perm, but only one will gain entry to the egg. As the winning sperm pushes through the outer case of the egg, a chemical reaction shuts out all the other sperm. The successful sperm then fuses with the nucleus of the egg, and fertilization is complete. An embryo is formed, which will eventually develop into a baby.

The term “gestational age” basically means how far along into a pregnancy you are. Gestational age is counted by starting with the first day of your last menstrual period (called LMP).

Gestational age can be kind of confusing, since it measures pregnancy from your last period — about 3-4 weeks BEFORE you’re actually pregnant. Common knowledge about pregnancy says it lasts 9 months, and it’s true that you’re usually pregnant for about 9 months. But the way pregnancy is measured makes it a little longer. A typical full-term pregnancy ranges from 38-42 weeks LMP — around 10 months.

 

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