Respiration in Humans Flashcards
What is aerobic respiration?
Aerobic respiration is the breakdown of food substances in the presence of oxygen, with the release of carbon dioxide, water and a large amount of energy.
What is anaerobic respiration?
Anaerobic respiration is the breakdown of food substances in the absence of oxygen, releasing less energy than aerobic respiration.
How does vigorous exercise affect the way a person respires?
If there is insufficient oxygen to meet the demands of the vigorous muscular contractions, the muscles are said to incur an oxygen debt. Lactic acid concentration builds up slowly in the muscles and might cause fatigue and muscular pains. While resting, the breathing rate continues to be fast to provide sufficient oxygen to the muscle cells. Lactic acid is also gradually removed from the muscles and transported to the liver, where some of it is oxidised while the rest of it is converted into glucose.
What are the advantages of breathing through the nose?
- Dust and foreign particles are trapped by the nostril hair as well as mucus
- Air that passes through the nasal passages is warmed and moistened
- Harmful chemicals may be detected by small sensory cells in the mucous membrane
What type of cells are present in the trachea?
Gland cells - secretes mucus to trap dust particles and bacteria
Ciliated cells - have cilia that sweep dust-trapped mucus up the trachea.
How are the lungs adapted for efficient gas exchange?
- Numerous alveoli -> large surface area
- Wall of alveolus is one cell thick -> shorter diffusion distance -> faster rate of diffusion
- Thin film of moisture covers alveolus -> allows oxygen to dissolve
- Walls of alveoli richly supplied with blood capillaries -> concentration gradient
How are the oxygen and carbon dioxide concentration gradients between the alveolar air and the blood maintained?
- Continuous flow of blood through the blood capillaries
- Movement of air in and out of alveoli (breathing)
How is oxygen absorbed in the lungs?
The alveolar wall is permeable to oxygen and carbon dioxide. Since the alveolar air contains a higher concentration of oxygen than the blood, the oxygen dissolves in the moisture lining the alveolar walls. It then diffuses into the blood capillaries, and combines with haemoglobin to form oxyhaemoglobin. When the blood passes through oxygen-poor tissues, the oxyhaemoglobin releases oxygen, which will then diffuse through the walls of the blood capillaries into the cells of tissues.
How is carbon dioxide removed from the lungs?
As blood passes through tissues via blood capillaries, carbon dioxide diffuses into the blood and enters the red blood cells. It then reacts with water in the red blood cells to form carbonic acid, with carbonic anhydrase as a catalyst. Carbonic acid is then converted into hydrogencarbonate ions, which diffuse out of the red blood cells and get carried by blood plasma. In the lungs, the ions diffuse back into the red blood cells, where they are converted into carbonic acid, then into water and carbon dioxide. It then diffuses out of the blood capillaries and into the alveoli, where it is expelled.
What are the events that take place when a person inspires?
- Diaphragm muscle contracts and diaphragm flattens
- Relax Internal intercostal muscles, Contract External intercostal muscles
- Ribs move upwards and outwards
- Thoracic cavity volume increases
- Lungs expand and air pressure decreases
What are the events that take place when a person expires?
- Diaphragm muscle relaxes and diaphragm arches upwards
- External intercostal muscles Relax while Internal intercostal muscles Contract
- Ribs move downwards and inwards
- Thoracic cavity volume decreases
- Lungs compress and air pressure increases
What are the effects of nicotine on the body?
Nicotine is an addictive drug that causes the release of adrenaline and makes blood clot easily. As a result, it can increase heartbeat rate and blood pressure, as well as risk of coronary heart disease.
What are the effects of carbon monoxide on the body?
Carbon monoxide combines with haemoglobin to form carboxyhaemoglobin. It also increases the rate of fatty deposits on the inner arterial wall. As a result, it can reduce the ability of blood to carry oxygen, narrow the lumen of arteries, increase blood pressure and eventually lead to an increased risk of coronary heart disease.
What are the effects of tar on the body?
Tar can cause uncontrolled cell division and paralyse cilia lining the air passages. As a result, it can increase risk of cancer, chronic bronchitis and emphysema as dust particles trapped in mucus cannot be removed.
What are the effects of irritants (hydrogen cyanide, formaldehyde etc.)
Irritants can paralyse cilia lining the air passages. As a result, it can increase the risk of chronic bronchitis and emphysema as dust particles trapped in mucus cannot be removed.
