Unit 3 - Circulatory systems Flashcards Preview

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Flashcards in Unit 3 - Circulatory systems Deck (27)
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1
Q

Give 5 reasons why specialist transport systems are needed

A
  • metabolic demands of most animals is high
  • SA:V decreases as animal size increases so diffusion distances increase whilst SA avaliable becomes relatively smaller
  • molecules are made in one place but needed in another
  • food will be digested in one organ system but needs to be transported to every cell
  • waste products of metabolism need to be removed from cells and transported to excretory systems
2
Q

As an organism gets larger what happens to the diffusion distance?

A

It gets larger

3
Q

Why does a greater level of activity in an organism increase demand for glucose and oxygen?

A
  • more activity requires more energy
  • more energy requires more aerobic respiration
  • which requires more reactants (oxygen and glucose)
4
Q

Why does a greater volume of an organism mean a greater demand?

A
  • greater volume means greater number of cells
  • each cell requires energy
  • so demand for energy/glucose/oxygen increases
5
Q

Define mass flow

A

the movement of fluids down a pressure or concentration gradient

6
Q

Define circulatory system

A

the transport system of an organism

7
Q

Define open circulatory system

A

a transport system with a heart but with few vessels to contain the transport medium

8
Q

Define closed circulatory system

A

the transport medium is enclosed in vessels and does not come into contact with the cells of the body

9
Q

Define haemolymph

A

the blood like fluid contained in insects

10
Q

Define single circulatory system

A

a circulatory system where the blood flows through the heart once during a complete circuit of the body

11
Q

Define double circulatory system

A

a circulatory system where the blood flows through the heart twice during a complete circuit of the body

12
Q

Define pulmonary circulation

A

The portion of the circulatory system which carries deoxygenated blood away from the right ventricle of the heart to the lungs and returns oxygenated blood to the left atrium and ventricle

13
Q

Define systemic circulation

A

The part of the cardiovascular system which carries oxygenated blood away from the heart to the body and returns deoxygenated blood back to the heart

14
Q

Give examples of organisms with a single closed circulatory system

A

Fish and annelid worms

15
Q

Give examples of organisms with a double closed circulatory system

A

Birds and most mammals

16
Q

Give an example of an organism with an open circulatory system

A

Insects

17
Q

Why are fish able to be highly active despite having a single closed circulatory system?

A
  • the countercurrent exchange mechanism means they can take up a lot of O2 from water
  • their body weight is supported by the water
  • they do not maintain their own body temperatures
18
Q

Why are single closed circulatory systems not very efficient?

A

Blood pressure drops considerably

so blood flows slowly back to the heart

19
Q

Why are double closed circulatory systems very efficient?

A
  • each circuit passes through only one capillary network
  • this maintains relatively high blood pressure
  • so fast flow of blood back to the heart is maintained
20
Q

What are the general features of circulatory systems?

A
  • fluid to transport dissolved gases, nutrients, and waste
  • a pumping mechanism to move fluid
  • sometimes vessels to carry the fluid
21
Q

How are open and closed circulatory systems different?

A
  • blood enclosed in vessels in closed but not in open
  • in open circulatory systems the fluid fills body cavities
  • open less efficient
22
Q

What is an advantage of having an open circulatory system?

A

less vulnerable to pressure

23
Q

What is an advantage of closed circulatory systems?

A

more efficient

24
Q

What is a disadvantage of open circulatory systems?

A

requires low metabolic rate so does not work for larger animals

25
Q

What is a disadvantage of closed circulatory systems?

A

requires more energy

26
Q

What are the differences between single and double circulatory systems?

A
  • go through the heart once in one complete circuit in single and twice in double
  • single has two sets of capillaries while double has one
  • double maintains higher pressure than single
27
Q

What is the disadvantage of single circulatory systems?

A

They are less efficient