exchange surfaces

Question 1

describe what happens as you breathe in

Answer 1

air enters trachea
trachea splits into 2 bronchi, one bronchus to each lung
each bronchus branches off into smaller tubes called bronchioles
the bronchioles end in small air sacs called alveoli where gases are exchanged

Question 2

what do the goblet cells do?

Answer 2

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

Question 3

what do the cilia do?

Answer 3

beat the mucus, this moves the mucus upward away from alveoli towards through where its swallowed, this prevents lung infection

Question 4

what do the elastic fibres do?

Answer 4

help the process of breathing out

Question 5

what do the smooth muscle do?

Answer 5

allows their diameter to be controlled, during exercise the smooth muscle relaxes, tubes widen, less resistance to airflow

Question 6

what do the rings of cartilage do?

Answer 6

provide support and is flexible to stop the trachea and bronchi collapsing when u breathe in and the pressure drops

Question 7

which part of the lung has a large c shaped pieces of cartilage, smooth muscle, elastic fibres , goblet cells and ciliated epithelium

Answer 7

trachea

Question 8

which part of the lung has a smaller pieces of cartilage, smooth muscle, elastic fibres , goblet cells and ciliated epithelium

Answer 8

bronchi

Question 9

which part of the lung has no cartilage, smooth muscle, elastic fibres , goblet cells and ciliated epithelium

Answer 9

larger bronchiole

Question 10

which part of the lung has no cartilage, smooth muscle, elastic fibres and ciliated epithelium

Answer 10

smaller bronchiole

Question 11

which part of the lung has no cartilage, elastic fibres no ciliated epithelium

Answer 11

smallest bronchiole

Question 12

which part of the lung has no cartilage, elastic fibres and no ciliated epithelium

Answer 12

alveoli

Question 13

explain the process of inspiration

Answer 13

the external intercostal and diaphragm muscles contract

this causes the ribcage to move upwards and outwards, and the diaphragm to flatten, increasing the volume of the thorax

as the volume of the thorax increases, the lung pressure decreases

this causes air to flow into the lungs

ITS AN ACTIVE PROCESS, REQUIRES ENERGY

Question 14

explain the process of expiration

Answer 14

the external intercostal and diaphragm muscles relax

ribcage move inwards and downwards and the diaphragm becomes curved again

thorax volume decreases, causing the air pressure to increase

air is forced out of the lungs

normal expiration=passive process

forced expiration=active process

Question 15

define tidal volume

Answer 15

the volume of air in each breath

Question 16

define vital capacity

Answer 16

the maximum volume of air that can be breathed in or out

Question 17

define breathing rate

Answer 17

how many breaths are taken usually in a minute

Question 18

define oxygen consumption or O2 uptake

Answer 18

the rate at which an organism uses up oxygen

Question 19

why is soda lime used in a spirometer?

Answer 19

it absorbs carbon dioxide so theirs only oxygen in the chamber which the subject inhales from

Question 20

what is a counter current system in fish?

Answer 20

when blood flows through the gill plates in one direction and water flows over in the opposite direction, it maintains a large concentration gradient between the water and the blood,

conc of O2 in water is always higher than that of blood so as much O2 diffuses from water into blood

Question 21

what do the gill plates have to speed up diffusion

Answer 21

lots of blood capillaries, thin branches called gill filaments and thin surface layer of cells

Question 22

describe fish ventilation

Answer 22

fish opens mouth lowering the floor of the buccal cavity.

volume of the buccal cavity increases decreasing the pressure inside the cavity

water is sucked into the cavity

Question 23

how does air move into the tracheae in an insect?

Answer 23

through pores on the insects surface called spiracles

Question 24

what movement do insects use to change the volume of their bodies and move air in and out of the spiracles

Answer 24

rhythmic abdominal movements

Question 25

why do multicellular organisms need exchange surfaces?

Answer 25

there is a big difference between some cells and the distance between them and the outside environment

larger animals have a smaller SA:VOL, its difficult to supply a large volume of animal through a relatively small outer surface

they have a high metabolic rate so they use up O2 and glucose faster

Question 26

how are root hair cells adapted to improve their efficiency

Answer 26

the cells on plant roots grow into long hairs, which stick out into the soil, this gives roots a large surface area which helps to increase the rate of absorption of water and mineral ions from the soil

Question 27

how is the alveoli adapted to improve their efficiency

Answer 27

each alveolus is made from a single layer of thin flat cells called the alveolar epithelium

surrounded by a large capillary network giving each alveolus its own blood supply, blood constantly takes away oxygen and brings CO2, these features help maintain the conc gradient

Question 28

how are fish gills adapted to improve their efficiency

Answer 28

fish gills contain a large network of capillaries so they are well supplied with blood

well supplied with blood-fresh water constantly passes over them