lungs + measuring the process- exchange and transport

Question 1

adaptions of root hair cells which increase the rate of water absorption

Answer 1

• the cells on plant roots grow long ‘hairs’ which stick out into the soil
• each branch root covered in millions of these
• gives root larger SA which helps increase the rate of absorption of water by osmosis and mineral ions

Question 2

adaptations of alveoli for max diffusion of gases

Answer 2

• each alveolus made of a single layer of flat, thin cells called the alveolar epithelium
• helps decrease the distance of diffusion=increase rate
• good blood supply, each alveolus surrounded by large capillary network=gives it own blood supply
• ventilated lungs bring o2 rich air in

Question 3

order of the ‘bronc’ family

Answer 3

• trachea splits into 2 bronchi- 1 bronchus leading to each lung
• each bronchus branches off into smaller tubes called bronchioles
• bronchioles end in small air sacs =alveoli

Question 4

function of goblet cells

Answer 4

• secrete mucus

- mucus traps microorganisms and dust particles in the inhaled air, stopping them from reaching alveoli

Question 5

where are goblet cells found

Answer 5

-line airways (trachea, bronchi, larger bronchiole)

Question 6

function of cilia

Answer 6

-beat the mucus upward and away from alveoli towards the throat, where its swallowed = prevents lung infections

Question 7

where cilia found in gaseous exchange system

Answer 7

-trachea, all broncs bar smallest brochiole

Question 8

function of elastic fibres in gaseous exchange system

Answer 8

-in every part, aid the process of breathing out as the are stretched during inspiration and recoil during expiration which helps push the air out

Question 9

purpose of smooth muscle in walls of trachea, bronchi and bronchioles

Answer 9

• allows their diameter to be controlled
• during exercise the smooth muscle relaxes, making the tube wider= less resistance to airflow as it can move in and out of lungs easily

Question 10

function of rings of cartilage on walls of trachea and bronchi

Answer 10

-provide support, stops the trachea and bronchi collapsing when you breathe in and the pressure drops

Question 11

steps of inspiration/inhalation

Answer 11

• external intercostal and diaphragm muscles contract
• causes ribcage to move upwrads and out and diaphragm flattens, increasing volume of the thorax
• as vol of thorax increases, lung pressure decreases=causes air to flow into lungs

Question 12

steps of expiration/exhalation

Answer 12

• external intercostal and diaphragm muscles relax
• ribcage moves downwards and inwards and diaphragm becomes curved again
• thorax vol decreases, causing lung pressure to increase = air is forced out of the lungs

Question 13

tidal volume

Answer 13

-vol of air in each breath, usually around 0.4dm^3

Question 14

vital capacity

Answer 14

-max vol of air that can be breathed in or out

Question 15

breathing rate

Answer 15

-how many breaths are taken, usually in a minute

Question 16

oxygen consumption/uptake

Answer 16

-rate at which organism uses up oxygen

Question 17

spirometer

Answer 17

-machine that can give readings of tidal vol, vital capacity, breathing rate and oxygen uptake

Question 18

reasons why multicellular organisms need exchange surfaces

Answer 18

diffusion across outer membrane is too slow because;

• some cells deep within the body, large distance from outside environment
• small SA to vol ratio
• higher metabolic rates than single celled organisms=take up o2 and glucose faster

Question 19

features of nasal cavity

Answer 19

• large sa with good blood supply, warms the air to body temperature
• hairy lining, secretes mucus to trap dust and bacteria, protecting lung tissue from infection
• moist surfaces, increase the humidity of the incoming air, reducing evaporation from the exchange surfaces

Question 20

role of the lung surfactant on the surface of alveoli

Answer 20

• keeps the alveoli inflated
• reduces surface tension at the air–water interface in the alveoli, thereby preventing collapse of these structures at end-expiration
• O2 dissolves in surfactant before the blood

Question 21

inspiratory reserve volume

Answer 21

-the max vol of air you can breathe in over and above a normal inhalation

Question 22

expiratory reserve volume

Answer 22

-extra amount of air you can force out of your lungs over and above the normal tidal volume of air you breathe out

Question 23

residual vol

Answer 23

vol of air left in lungs when fully exhaled

Question 24

total lung capacity

Answer 24

sum of vital capacity and residual vol