Transport in Animals

Question 1

Why do multicellular organisms need transport systems?

Answer 1

• They have low SA:V ratio
• They have higher metabolic rate

Question 2

Why do most active organisms need a transport systems?

Answer 2

• Large no. of respiring cells
• Constant supply of glucose and O2

Question 3

What is a single circulatory system?

Answer 3

When blood only passes through the heart once for each circuit

Question 4

What is a double circulatory system?

Answer 4

When blood passes through heart twice for every circuit

Question 5

Where does the systemic system send blood in mammals?

Answer 5

To the body

Question 6

What is the main advantage of a double circulatory system?

Answer 6

• Heart gives blood an extra push
• Blood travels faster and more O2 delivered to tissues quicker

Question 7

What is an open circulatory system?

Answer 7

When blood flows freely through the body

Question 8

Do mammals have an open or closed circulatory system?

Answer 8

Closed - within blood vessels

Question 9

Give an example of an organism with an open circulatory system

Answer 9

Insects

Question 10

Which type of circulatory system supplies O2?

Answer 10

Closed

Question 11

Describe the structure of an artery

Answer 11

• Thick + Muscular walls
• Elastic tissue for stretch and recoil
• Folded endothelium allows arteries to expand

Question 12

State two differences between arterioles and arteries

Answer 12

• Arterioles are much smaller
• Smooth muscle controls blood flow to tissue

Question 13

How big is the lumen of capillaries?

Answer 13

One RBC thick

Question 14

What do venules contain within their walls?

Answer 14

Muscle cells

Question 15

Describe the structure of veins

Answer 15

• Wider lumen
• Little elastic/muscle tissue
• Valves prevent backflow

Question 16

How can blood flow through veins be aided?

Answer 16

Muscle contraction

Question 17

What is tissue fluid made from?

Answer 17

Substances that diffuse out of blood plasma

Question 18

What proecss causes substances to move out of capillaries?

Answer 18

Pressure filtration

Question 19

Explain the process that forms tissue fluid

Answer 19

• At the artery end, hydrostatic pressure is greater than hydrostatic pressure of tissue fluid
• Pressure difference forces fluid out of capillaries; into gaps

Question 20

What is oncotic pressure?

Answer 20

Pressure generated from plasma proteins

Question 21

Explain why water re-enters capillaries at the venule end of capillaries

Answer 21

• H2O potential of blood lower than H20 potential of tissue fluid
• Due to loss of fluid and high oncotic pressure
• Water moves back into capillaries by Osmosis

Question 22

Where does excess tissue fluid go?

Answer 22

• Drains into lymph vessels, becoming lymph

Question 23

How do lymph vessels prevent backflow of lymph?

Answer 23

Valves

Question 24

What is tissue fluid mainly comprised of?

Answer 24

Water, dissolved solutes

Question 25

What cells does lymph contain?

Answer 25

WBC's

Question 26

What are the only proteins found in lymph?

Answer 26

Antibodies

Question 27

Does tissue fluid contain proteins?

Answer 27

Only very small ones

Question 28

Does tissue fluid contain red blood cells?

Answer 28

NO

Question 29

Do platelets leave the capillaries?

Answer 29

NO

Question 30

Explain how a valve works

Answer 30

- Higher pressure behind a valve forces it open - Higher pressure in front forces it closed

Question 31

Where are semi-lunar valves found?

Answer 31

In-between ventricles and pulmonary artery/aorta

Question 32

What are the 3 stages of the cardiac cycle?

Answer 32

- Atrial contraction - Ventricular contraction - Diastole

Question 33

What occurs during atrial contraction?

Answer 33

- Atrial pressure increases - Blood forced through AV valve - Ventricles receive blood

Question 34

What occurs during ventricular contraction?

Answer 34

- Ventricular pressure increases - AV valve forced shut due to higher pressure in ventricles - Semi-lunar valve opens due to higher pressure behind valve

Question 35

What occurs in diastole?

Answer 35

- Higher pressure in arteries forces semi-lunar valves shut - Atria fill with blood due to high pressure in the vena cava - AV valve opens, blood flows into ventricles passively

Question 36

How do you calculate cardiac output?

Answer 36

Heart rate x Stroke volume

Question 37

What does 'myogenic' mean?

Answer 37

- Can contract and relax without nerve signals

Question 38

What is the function of the sino-atrial node?

Answer 38

Sets rhythm of heartbeat by sending out regular waves of electrical activity to AVN

Question 39

What is the role of the AVN?

Answer 39

Passes electrical waves to bundle of His

Question 40

Why does the AVN leave a slight delay before passing impulses to bundle of His?

Answer 40

To ensure atria are empty

Question 41

What is the role of the Bundle of His?

Answer 41

Group of muscle fibres; conduct electrical waves to Purkyne tissue

Question 42

What is the role of Purkyne tissue?

Answer 42

To carry electrical waves to muscular, ventricular walls so they contract upwards

Question 43

Why do ventricles contract from the bottom up?

Answer 43

To push blood up and out of the heart

Question 44

Give the order for controlling heart activity

Answer 44

SAN - AVN - Bundle of His - Purkyne tissue

Question 45

What is the P wave caused by?

Answer 45

Atrial contraction

Question 46

What is the QRS complex caused by?

Answer 46

Ventricular contraction

Question 47

Why do ECG's have a T wave?

Answer 47

Due to relaxation of ventricles

Question 48

In ECG's, what does the height of a wave represent?

Answer 48

Strength of contraction

Question 49

What is tachycardia?

Answer 49

Resting heart rate is too fast. >120bpm

Question 50

What is bradycardia?

Answer 50

Heart rate is too slow

Question 51

What is fibrillation?

Answer 51

When heartbeat is irregular, unsynchronised

Question 52

How many polypeptide chains is Haemoglobin made of?

Answer 52

4

Question 53

How many oxygen molecules can bind to haemoglobin?

Answer 53

4

Question 54

What does 'high affinity for O2' mean?

Answer 54

Tendency to combine with oygen

Question 55

What occurs to haemoglobin at a high pO2?

Answer 55

O2 loads onto Hb

Question 56

What occurs to haemoglobin at a low pO2?

Answer 56

O2 unloads off Hb

Question 57

Why do alveoli have a high pO2?

Answer 57

So O2 loads onto Hb

Question 58

Explain why the %saturation/pO2 graph is S-shaped

Answer 58

- When the first O2 molecule joins, Hb's shape alters so binding is easier - After 3/4 molecules have binded, it is unlikely for another to collide with empty space

Question 59

How does the heart ensure that contraction occurs from the bottom up?

Answer 59

Non-conducting collagen tissue prevents waves being passed directly from atria to ventricles

Question 60

Does heart muscle depolarise when it relaxes?

Answer 60

Depolarises --> Contraction