Gas Exchange and Smoking

Question 1

What is the structure of the human gas exchange system?

Answer 1

trachea, bronchi, bronchioles, alveolar sacs, alveoli, lungs

Question 2

What is the structure of the trachea?

Answer 2

airway leading from throat to lungs, c shaped cartilage rings, 1.8 cm, goblet cells, smooth muscle, cilia

Question 3

What is the structure of the bronchi?

Answer 3

two bronchi form bronchial tree in each lung, 1.2 cm, irregular blocks of cartilage, goblet cells, smooth muscle, cilia

Question 4

What is the structure of the terminal bronchioles?

Answer 4

bronchioles branch into terminal bronchioles, 48000, 1 mm, smooth muscle, cilia

Question 5

What is the structure of the alveoli?

Answer 5

alveolar ducts branch into alveoli, 3 x 10^9, 250 μm, site of gas exchange, elastic fibres, blood capillaries

Question 6

What is cartillage?

Answer 6

connective tissue, keeps airways open, keeps air resistance low, prevents airways from collapsing

Question 7

What is the ciliated epithelium?

Answer 7

the epithelium containing ciliated cells with cilia which continually beat to push mucus upwards

Question 8

What are goblet cells?

Answer 8

found in the ciliated epithelium of the trachea and bronchi, produce mucin droplets made of glycoproteins

Question 9

What is smooth muscle?

Answer 9

surrounds bronchioles, contracts and relaxes, controls air flow to alveoli

Question 10

What is the squamous epithelium?

Answer 10

flattened epithelial cells present in the alveoli

Question 11

What are mucous glands?

Answer 11

produce mucus, beneath epithelium

Question 12

What are elastic fibres?

Answer 12

fibres which give elasticity, present in alveolar walls, stretch during inspiration, increase surface area for diffusion during exercise, recoil during expiration, push out air forcefully

Question 13

What is the process of gas exchange between the alveoli and blood?

Answer 13

oxygen diffuses down a concentration gradient from the alveoli to the capillaries, carbon dioxide diffuses from the capillaries into the alveoli

Question 14

What is tar?

Answer 14

a carcinogen-containing compound found in cigarette smoke which settles on the linings of the airways

Question 15

What are carcinogens?

Answer 15

cancer-causing agents

Question 16

What is lung cancer?

Answer 16

carcinogens in tar react with DNA in epithelial cells to produce mutations, development of tumour, cancer spreads to lymphatic tissues, secondary tumours establish, 20-30 years to develop, located by bronchoscopy, chest X-ray, or CT scan, treated with surgery, chemotherapy, radiotherapy

Question 17

What are COPDs?

Answer 17

chronic obstructive pulmonary diseases such as asthma, chronic bronchitis, and emphysema which can be caused by air pollution or tobacco smoke

Question 18

What is nicotine?

Answer 18

the highly addictive drug in tobacco which stimulates nerve endings to release dopamine

Question 19

What are the effects of nicotine?

Answer 19

absorbed readily by blood, travels quickly to brain, stimulates nervous system to reduce diameter of arterioles, release adrenalin, heart rate and blood pressure increases, decrease in blood supply to hands and feet, increases risk of blood clotting

Question 20

What is carbon monoxide?

Answer 20

compound formed when tobacco is burned incompletely

Question 21

What are the effects of carbon monoxide?

Answer 21

diffuses across walls of alveoli and into blood in lungs, diffuses into red blood cells, forms stable compound oxyhaemoglobin, haemoglobin is not fully oxygenated, less oxygen is supplied to heart muscle, straining it, arteries may also be damaged

Question 22

What is the structure of the respiratory bronchioles?

Answer 22

terminal bronchioles form respiratory bronchioles, 300000, 0.5 mm, a few cilia

Question 23

What is the structure of the alveolar ducts?

Answer 23

respiratory bronchioles branch into alveolar ducts, 9 x 10^6, 400 μm, site of gas exchange, elastic fibres

Question 24

What is chronic bronchitis?

Answer 24

damage and obstruction of airways; tar stimulates goblet cells and mucus glands to enlarge and secrete more mucus, it also destroys and weakens cilia, mucus accumulates in bronchioles and they become obstructed, causes smoker’s cough, scar tissue, thickens smooth muscle, infections develop easily, linings become inflamed, phlegm

Question 25

What is emphysema?

Answer 25

inflammation of infected lungs causes phagocytes to release elastase to reach lining of lungs from capillaries, elastase destroys elastin, alveoli do not stretch and recoil, bronchioles collapse, alveoli burst, less surface area for gas exchange, less oxygen absorbed in blood, blood vessels in lungs become resistant to blood flow, blood pressure increase, right side of heart enlarges, wheezing and breathlessness