respiration 2

Question 1

what happens when you inhale and exhale

Answer 1

-diaphragm contracts and flattens, external intercostal muscle contract, rips move up and out, sternum moves up and forward, volume in thoracic cavity increases, pressure in lungs causes them to expand to fill up enlarged thorax, expansion of lungs decreases the air pressure inside which is now lower than atmospheric pressure so air rushes into lungs
-diaphragm relaxes and arches upwards, internal intercostal muscle contract, rips downwards and inwards, sternum moves to original position, volume in thoracic cavity decreases, lungs are compressed so air pressure inside them increases as volume decreases which is now lower that atmospheric pressure so air is forced out of lungs to exterior

Question 2

explain the conditioning of air

Answer 2

-before reaching lungs, air is moistened, filtered and warmed
-the air picks up moisture from the mucus in the mucous membrane and is warmed by the body temperature
-filtration of air is accomplished by trapping and removing dust particles, bacteria and foreign matter by cilia and mucus

Question 3

how is infected mucus removed

Answer 3

-cilia, hair like structures in the mucous membrane move constantly, transporting layer of mucus laden with dust particles and foreign matter towards pharynx to be sneezed or swallowed

Question 4

adaptation of alveoli

Answer 4

-there are millions of alveoli to providing a large SA for gaseous exchange
-walls of alveoli are covered in a layer of water to dissolve the gas
-walls of alveoli are one cell thick for quick and easy diffusion of gaseous and solutions
-richly supplied with capillaries for rapid transport of gases which result in a steep concentration gradient that increases the rate of diffusion

Question 5

properties and effects of nicotine

Answer 5

-stimulates the brain into making the smoker feel alert and relaxes the muscles, then dulls the brain and senses
-causes the release of adrenaline increasing heartbeat and blood pressure
-makes blood clot easily increasing the risk of heart attacks and strokes

Question 6

properties and effects of carbon monoxide

Answer 6

-competes with oxygen for haemoglobin, a slight increase can cause unconsciousness leading to death
-damages the lining of blood vessels and increases the risk of them clotting
-increase the rate at which fatty substances and deposited into the inner walls of arteries which narrows the lumen

Question 7

properties and effects of tar

Answer 7

-contains cancer causing substances, causes cilia lining the air passages to stop beating, preventing it from removing dust particles from the trachea so it enters our lungs

Question 8

how does chronic bronchitis occur and what is its effect

Answer 8

-smoking tobacco or air pollution leads to continual bronchial inflammation and irritation
-epithelium lining the airways become inflamed, excessive mucus is secreted by it
-cilia on the epithelium is paralysed so mucus and dust particles cannot be removed
-airways become blocked, difficulty breathing, developing a persistent cough to try and clear airways which could lead to lung infections

Question 9

how does emphysema occur and what is its effect

Answer 9

-tobacco smoke and air pollution together with antitrypsin deficiency lead to breakdown of elastin in connective tissue of lungs
-persistent and violent cough may lead to emphysema where destruction of alveoli walls occur
-reduction of surface area for gaseous exchange, lungs loses elasticity, inflated with air, difficulty breathing, wheezing and breathlessness