Circulation-Closed/open Flashcards Preview

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Flashcards in Circulation-Closed/open Deck (22):
1

Define 'Mass flow'

The movement of fluids down a pressure gradient

2

Why do animals use mass flow

Diffusion is too slow to meet animals needs

3

What is diffusion/osmosis/active transport used for in animals

Moving substances over short distances

4

What sort of organisms move substances with diffusion

Very small organisms such as unicellular creatures

5

What do most animals use blood for

Carrying vital substances around the body

6

Main function of of exchange surfaces?

To establish and maintain differences in concentration and pressure

7

Two examples of mass flow systems

-blood system of a mammal
-xylem sand phloem in a plant

8

Four features of a mass flow system

-a system of vessels (usually tubes) to carry substances
- Away of making substances move in right direction
-A means of moving substances fast enough to supply the needs of the organism
- A suitable transport medium

9

Describe an open circulation system
(Five points*)

-A simple heart*pumps blood into cavities surrounding organisms organs*,substances diffuse from the blood into/out of cells*.
-When heart muscle relaxes*, blood is drawn back into heart through small valve openings along the length of the heart *

10

Name two examples of organisms with open circulation

-Insects
-Giant spider crabs

11

What's insect blood called

Hemolymph

12

What sort of animals have closed circulatory systems

-Generally larger and more active than those with open
-All vertebrates

13

Main diffence between open and closed systems

In closed systems the blood is enclosed within tubes (arteries, veins, capillaries)

14

Main advantage of closed circulation

-Generates higher blood pressure
-means blood flows faster so more efficient at delivering substances around the body

15

Function of valves?

To ensure blood flows in right direction

16

What type of system allows blood to flow through the heart only once

Single circulatory system

17

Describe circulation of a fish
(3 points)

-Heart pumps deoxygenated blood to gills
-blood passes through gills(large surface area) oxygen and Co2 diffuse in/out from/into water
-Blood leaves gills, flows round rest of body back to heart

18

Describe double circulation

-Right ventricle pumps deoxygenated blood(through pulmonary artery) to the lungs to become oxygenated
-Returns to heart oxygenated and is pumped a second time to rest of the body
-returns to heart

19

Where dose the left ventricle pump blood to (what pressure)

At high pressure to the body

20

Where dose he right ventricle pump blood to (what pressure)

Pumps blood to lungs at a low pressure-to reduce risk of damaging lungs

21

What pressure is pulmonary circulation at?
(Blood towards lungs)

Max 40mmHg

22

What pressure is systematic circulation at
(To all body parts except lungs)

120mmHg