Transport in animals Flashcards

Module 2

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1
Q

What is the difference in surface area to volume ration in small and large organisms

A

Small organisms have a Large SA to Vol ratio
Large organisms have a small SA to Vol ratio

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2
Q

Why do large organisms need a specialised system

A

More metabolically active
Distance is too great for the molecules to travel
Diffusion is too slow
O2 and nutrients would all be used up in the first layers

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3
Q

What are the types of circulatory systems

A

Open
Closed
Double
Single
Partially double

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4
Q

What is an Open circulatory system

A

Found in Invertebrates/Insects
No/very few blood vessels
Gas exchange takes place in the tracheal system - has haemolymph
Haemolymph flow cannot be adjusted

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5
Q

Why do mammals need more energy than reptiles

A

mammals are endotherms and so will need more energy to maintain the homeostasis of temperature

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6
Q

What is a Closed circulatory system

A

In vertebrates
Has blood vessels
Blood flow can be adjusted
Haemoglobin

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7
Q

What is a Double circulatory system

A

In birds + mammals
Most efficient
Has two separate circulations
- heart to lungs
- heart to rest of the body
High pressure + blood flow can be maintained

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8
Q

What is a Single circulatory system

A

Found in fish
Blood passes through two sets of capillaries before it returns to the heart
Slower as high pressure is not maintained
Provides less energy

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9
Q

What is a partial double circulatory system

A

In amphibians and some reptiles
One circuit goes to lungs then tissues, another straight to tissues
Not efficient as deoxygenated and oxygenated blood mixed
this means some RBCs that go to tissues are empty

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10
Q

What are the different components + their functions in blood vessels

A

Elastin fibres - stretch and recoil so provide flexibility
smooth muscle - change size of lumen
collagen fibres - provides structural support

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11
Q

Features of arteries

A

Maintain pressure
- elastin fibres stretch and recoil
Withstand pressure
- Thick walls
- lots of collagen and folded endothelium

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12
Q

What are arterioles

A

link arteries and capillaries
more smooth muscle that can contract to reduce blood flow
less elastin than arteries

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13
Q

What is vasoconstriction

A

When the smooth muscle in the arteriole contracts, it constricts the vessel and prevents blood flowing into the capillary

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14
Q

What are capillaries

A

Microscopic blood vessels that link arterioles with the venules
They form an extensive network throughout the body

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15
Q

What are the parts of the capillary

A

Capillary wall and lumen

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16
Q

What is special about the capillary walls

A

They have large gaps between endothelial cells where substances can pass through
- The exception is capillaries in CNS

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17
Q

How are capillaries adapted for their role

A

Provides large S.A for diffusion
Cross section of capillaries>cross section of arterioles - slow blood flow
Single Cell thick

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18
Q

Features of Veins

A

Have valves
Have a larger lumen
has skeletal muscle pump

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19
Q

What happens at the venule end of the capillary

A

Lowered

20
Q

Why is the left ventricle thicker

A

Needs more pressure to be able to pump blood all around the body

21
Q

What is the heart muscle tissue called

A

Cardiac muscle/myocardium tissue

22
Q

What is the definition of myogenic

A

When a muscle can contract or relax without nervous stimulation

23
Q

What is the process of the cardiac cycle

A

During Diastole:
- 4 chambers relax
- blood flows in from veins (70% in ventricles)
Atrial systole starts:
- L + R atrium contract
- Increase in blood pressure causes the remaining 30% of blood to move to the ventricles
- AV valves close
Ventricular systole starts:
- Ventricular contraction starts at apex
- blood pushed up
- SL valves opens and blood enters arteries

24
Q

What is the process of the control of the cardiac cycle

A

SAN produces wave of excitation, atrial walls contract
Non conducting tissue delays wave from passing to ventricles
AVN picks up wave
Wave passes down the septum in purkyne fibres and causes ventricles to contract
Ventricular contraction starts at apex

25
Q

What is an ECG

A

Electrocardiogram

26
Q

What does P represent in an ECG

A

Atrial stimulation

27
Q

What does QRS represent in an ECG

A

Ventricular stimulation

28
Q

What does T represent in an ECG

A

diastole

29
Q

What effect does fibrillation have on the heartbeat

A

Causes it to be uncoordinated
- this could result in unconsciousness or death

30
Q

Why are arteries lined by endothelium cells

A

The flattened cells reduce friction

31
Q

Features of red blood cells

A

Biconcave - large SA
No nucleus - more space for Hb
Has Hb to carry O2
7um so there is a short diffusion path

32
Q

Advantages of blood vesseld

A

High blood pressure maintained
Flow can be diverted

33
Q

What causes high hydrostatic pressure

A

Ventricular systole

34
Q

Why does hydrostatic pressure drop as it moves away from the heart

A

There are more vessels, that have a larger lumen area so there is a reduced resistance to blood

35
Q

What is the Bohr effect

A

When the amount of O2 released can be increased by the presence of more carbon dioxide

36
Q

Why is the dissociation curve an S shape

A

Due to the conformational nature of the red red blood cells

37
Q

What type of cells are RBC

A

erythrocytes

38
Q

Why is the disassociation curve for foetal oxyhaemoglobin more left

A

It has a higher affinity, so it takes up O2 in lower partial pressure of O2
At low partial pressure of O2, adult Hb will dissosociate

39
Q

Why does the Bohr shift ensure more efficient delivery of O2

A

Respiring tissue needs more O2 for aerobic respiration, so it produces more CO2
Hb is involved in transport of CO2 so less is available to combine with O2
so more O2 will be released

40
Q

What is the process of the release of CO2

A

CO2 diffuses from respiring cell to tissue fluid to plasma to the RBC
CO2 + H2O -> H2CO3 -> H+ + HCO3-
Catalysed by carbonic anhydrase
H+ reacts with Haemoglobin
Cl- moves in when HCO3- moves out

41
Q

Why does the chlorine shift occur

A

Because of a charge imbalance

42
Q

What is arrhythmia

A

An irregular heartbeat

43
Q

What is an ectopic heartbeat

A

When a beat is skipped or added

44
Q

What is Bradycardia

A

Slower heartbeat

45
Q

What is tachycardia

A

Faster heartbeat