Respiration In Humans Flashcards
How are the lungs adapted for efficient gas exchange?
- The numerous alveoli in the lungs provide a large surface area—>increases surface area to volume ratio
- The wall of an alveolus is only one cell thick—> this provides a short diffusion distance for gases—> faster rate of diffusion
- A thin film of moisture covers the surface of the alveolus —> allows oxygen to dissolve in it
- The walls of the alveoli are richly supplied with blood capillaries—> the flow of blood maintains a steep concentration for efficient rate of diffusion.
How is CO2 removed from the lungs?
- Tissue cells produce a large amount of CO2 as a result of aerobic respiration.
- As blood passes through these tissues via blood capillaries. The tissue cells have a higher concentration of CO2 compared with the blood capillaries. The CO2 diffuses into the blood capillaries and enters the RBCs.
- The CO2 then reacts with H2O in RBCs to form carbonic acid—>catalyzed by the enzyme carbonic anhydrase which is present in the RBCs
- The carbonic acid is then converted into hydrogencarbonate ions which diffuse out of the RBCs into the blood plasma.—>most of the CO2 is carried as hydrogencarbonate , a small amount of CO2 is carried and dissolved in RBCs
- In the lungs, hydrogencarbonate ions diffuse back into the RBCs where they are converted into carbonic acid, then carbon dioxide.
- The CO2 then diffuses out of the blood capillaries and into the alveoli, where it is expelled when you breathe out.
What happens during inspiration?
RICE:
- The diaphragm muscle contracts and diaphragm flattens.
- Relax Internal intercostal muscles while the External intercostal muscles Contract.
- Ribs move upwards and outwards.
- Volume of thoracic cavity increases—> lungs expand—> lessee air pressure than atm—> forces atmospheric air into the lungs
What happens during exhalation?
ERIC:
- Diaphragm muscle relaxes and arches upwards
- External intercostal muscles Relax while Internal intercostal muscles Contract
- Ribs move downwards and inwards
- Volume of thoracic cavity decreases—>lungs are compressed—>air pressure increases as the thoracic cavity decreases—> air pressure in the lungs is higher than atm—> forces air out of the lungs.
Effects of nicotine in health
Properties of the chemical:
- Addictive drug that causes the release of adrenaline
- Makes blood clot easily
Effects on the body:
- Increases heartbeat—>increased blood pressure
- Increases risk of blood clots in the arteries—>increases risk of coronary heart disease
Effects of CO
Properties of chemical:
- Binds with haemoglobin to form carboxyhaemoglobin
- Increases the rate of fatty deposits on the inner arterial wall—>increases risk of coronary heart disease
Effects on the body:
- Reduces ability of blood to carry oxygen
- Narrows the lumen of arteries and leads to increase in blood pressure
Effects of Tar
Properties of chemical:
- Causes uncontrolled cell division
- Paralyses cilia lining the air passages
Effects on the body:
- Increases risk of cancer in lungs
- Dust particles trapped in the mucus lining the air passages cannot be removed—> increases risks of chronic bronchitis and emphysema
Effects of irritants
Properties of chemical:
1. Paralyse cilia lining the air passages
Effects on the body:
1. Dust particles trapped in the mucus lining the air passages cannot be removed—>increases risk of chronic bronchitis and emphysema.
What is Chronic bronchitis?
caused by paralysis of cilia
- The epithelium lining of air passages becomes inflamed
- Mucus and dust particles cannot be removed since the cilia on the epithelium are paralyzed—> blocks air passages—> makes breathing difficult—> persistent coughing to clear air passages
Emphysema
caused by persistent and violent coughing
- The partition walls between the alveoli break down due to persistent and violent coughing.
- This results in a decreased surface area for gaseous exchange.
Lung cancer
caused by tar
Cancer is the uncontrolled division of cells that produces outgrowths or lumps of tissues.
Anaerobic respiration equation
Glucose—>lactic acid+ small amount of energy
Definition: breakdown of food substances in the absence of oxygen, releasing small amount of energy with lactic acid as its waste product.
Aerobic respiration equation
Symbol:
C6H12O6 + 6O2 —-> 6CO2 + 6H2O + large amount of energy
Words:
Glucose + oxygen —> carbon dioxide + water + large amount of energy
Definition: breakdown of food substances in the presence of oxygen with the release of a large amount of energy. CO2 and H2O are released as waste products
