Module 3 - chapter 7 Flashcards Preview

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Flashcards in Module 3 - chapter 7 Deck (110)
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1

Why do we have cells?

Cells allow a concentration of chemicals in one area.

2

Why can’t we diffuse oxygen and carbon dioxide in through the skin?

The skin is a complete barrier so diffusion can’t occur.

3

What features must an efficient gas exchange system have?

Moist, thin walls. (E.g. the lungs are moist so gases can diffuse into them.) blood supply and ventilation

4

What are some reasons for exchange systems?

• Large multicellular organisms have a small surface area to volume ratio

•cells in the centre of the organism would not receive any materials if multicellular organs survived on diffusion alone.

•metabolic rate, multicellular organisms have a high metabolic rate

•there is a need to exchange lots of materials fast.

5

Why can single felled organisms survive using diffusion alone?

They have a low metabolic rate, and a large surface area to volume ratio

6

As surface area to volume ratio of an organism increases is diffusion easier or harder?

The easier the exchange of substances by diffusion is

7

What is the equation for the volume of a cuboid?

Volume = length x width x height

8

What is the equation for the surface area of a cuboid?

Surface area = (4 x length x height) + (2 x height x width)

9

What is the equation for the area of a circle?

Area = πr²

10

What is the equation for the circumference of a circle?

Circumference = 2πr

11

What is the equation for the volume of a cylinder?

Volume = πr² x height

12

What is the equation for the surface area of a cylinder?

Surface area = (2πr x height) + 2πr²

13

What is the equation for the volume of a sphere?

Volume = 4/3 x πr³

14

What is the equation for the surface area of a sphere?

Surface area = 4πr²

15

Why are thin layers a feature of an efficient gas exchange system?

The thin layers create a short diffusion pass for gases, increasing the speed of exchange

16

Why is blood supply a feature of an efficient gas exchange system?

A good, constant blood supply maintains a large diffusion gradient and ensures the exchanges substance are constantly moving to the area needed

17

Why is ventilation a feature of an efficient gas exchange system?

Ventilation maintains the diffusion gradient which makes the process faster and more efficient

18

List the structures for gas exchange in and around the lungs in the human body

Nasal cavity, mouth cavity, trachea, rings of cartilage, lungs, bronchi, bronchioles, heart, ribs, diaphragm.

19

Why are exchange surfaces moist?

To aid diffusion by oxygen dissolving into the water.

20

What are the gas exchange surfaces in humans?

Alveoli and bronchioles

21

Why do humans exchange gas?

To maintain a steep concentration gradient to aid diffusion.

22

What type of membrane are cell membranes?

plasma membranes

23

How thick are plasma membranes?

7 nm thick

24

What are the membranes which surround the heart called?

Cardiac membranes

25

What type of membrane is each lung encased in?

the pleural membrane (a double membrane.)

26

What is the space between the pleural membranes called?

The pleural cavity.

27

What is the pleural cavity filled with?

pleural fluid (a water-based fluid)

28

what is the function of the pleural fluid?

to lubricate the lungs and to adhere the outer walls of the lungs to the thoracic cavity

29

what is the thoracic cavity?

the chest cavity

30

how does the pleural fluid adhere the outer walls of the lungs to the thoracic cavity? why?

by water cohesion so that the lungs expand with the chest while breathing