Chapter 8- Transport In Animals

Question 1

What happens after atrial walls relax?

Answer 1

Ventricle walls contract

Question 2

What happens after the sinoatrial node generates electrical signals?

Answer 2

Walls of atria contract

Question 3

What happens after atrioventricular node receives electrical signals from SAN?

Answer 3

Electrical signals transmitted down septum

Question 4

What happens after ventricle walls contract?

Answer 4

Atrioventricular valves close

Question 5

What happens after ventricle walls relax?

Answer 5

Semilunar valves close

Question 6

If there are 2 ventricular systoles after the atrial systole in one heartbeat, what would happen?

Answer 6

Less blood leaves heart for each ventricular systole as ventricles do not have time to fill before contracting

Question 7

A fetus has a hole in the septum between the R + L atria which allows blood to flow directly from right atrium to left atrium. Why?

Answer 7

-lungs not functioning so blood is not oxygenated in lungs thus pulmonary circuit bypassed

Question 8

After birth, fetal haemoglobin replaced with adult haemoglobin. State differences + why important?

Answer 8

• fetal Hb has higher affinity for oxygen
• must be able to bind to oxygen in lower partial pressure in placenta
• fetal Hb contains gamma sub units
• creates higher affinity for oxygen

Question 9

Why tissue fluid does not contain erythrocytes?

Answer 9

Too large to pass through fenestrations between endothelium cells

Question 10

Role of haemoglobin in transporting oxygen around the body?

Answer 10

• oxygen binds to Hb in capillary to form oxyhaemoglobin

- oxygen dissociates from Hb + released to where needed

Question 11

How hydrogencarbonate ions are produced in erythrocytes?

Answer 11

• CO2 diffuses into erythrocytes
• CO2 reacts with water + catalysed by carbonic anhydrase enzyme
• forms carbonic acid
• carbonic acid dissociates to form hydrogencarbonate ions + hydrogen ions

Question 12

High concentrations of carbon dioxide in the blood reduces the amount of oxygen transported by Hb. Name this effect + why it occurs

Answer 12

• Bohr effect
• reduces the affinity of Hb for oxygen
• more oxygen released to where needed
• CO2 binds to Hb forming carbaminohaemoglobin

Question 13

What is meant by health?

Answer 13

Mental + physical well being and absence of disease

Question 14

Why fetal haemoglobin curve is to the left of the adult haemoglobin curve?

Answer 14

• fetal Hb has higher affinity for oxygen

- this is because it must be able to bind to O2 in low partial pressure in placenta

Question 15

How substances that are dissolved in blood plasma such as O2 + glucose enter the tissue fluid from capillaries?

Answer 15

• diffusion of substances down conc gradient
• hydrostatic pressure in capillary is higher than in tissue fluid so plaster forced out down pressure gradient
• as plasma moves out glucose + oxygen leave with it

Question 16

Pressure fluctuates as blood flows along aorta. Why

Answer 16

• ventricular systole of left ventricle increases pressure

- ventricular diastole of left ventricle decreases pressure

Question 17

Term used to describe no. Of fluctuations per minute?

Answer 17

Heart rate

Not heart beat

Question 18

What causes decrease in pressure as blood flows from sorta to arteries + arteries to capillaries?

Answer 18

• blood flows into larger no. of vessels
• total cross sectional area of arteries greater than of aorta
• total cross sectional area of capillaries greater than of aorta + arteries

Question 19

Why is it important that the pressure drops as blood flows from aorta to capillaries?

Answer 19

• capillary wall is very thin as only cell thick

- high pressure would damage capillary wall

Question 20

Hydrostatic pressure in arteriole blood?

Answer 20

High

Question 21

Hydrostatic pressure in tissue fluid?

Answer 21

Low

Question 22

Erythrocytes present in tissue fluid + lymph?

Answer 22

No

Question 23

Advantages of keeping blood inside vessel?

Answer 23

• maintain high bp

- flow can be directed

Question 24

How artery can withstand pressure?

Answer 24

• wall made of thick layer of collagen which provides strength
• endothelium is folded
• no damage to endothelium as it stretches

Question 25

How artery can maintain pressure?

Answer 25

- thick layers of elastic fibres to cause recoil | - smooth muscle constricts lumen

Question 26

Why wall of left ventricle is thicker than wall of left atrium?

Answer 26

-left ventricle needs to create higher pressure as pumps blood to all parts of body and thus has more muscle to create more force

Question 27

How pressure changes in the heart bring about the closure of the atrioventricular valve?

Answer 27

- ventricular systole - this raises pressure higher than atrial pressure - the pressure generated by ventricular contraction pushes valves shut

Question 28

How to maintain pressure of blood vessels?

Answer 28

- smooth muscle - elastic tissue - collagen - barrow lumen

Question 29

Exchange surface in mammalian circulatory system?

Answer 29

Capillaries Not alveoli as that is gas exchange system

Question 30

Transport medium in circulatory system?

Answer 30

- blood | - plasma

Question 31

How can the amount of oxygen released by dissociated from oxyhaemoglobin be increased + what is this called?

Answer 31

- presence of more CO2 | - Bohr effect

Question 32

Detail visible is use scanning electron microscope?

Answer 32

3D shape

Question 33

Detail visible if use transmission electron microscope?

Answer 33

Can see surface detail

Question 34

Why curve for fetal Hb is to the left of the curve for adult haemoglobin?

Answer 34

- fetal Hb has higher affinity for oxygen - fetal Hb must be able to bind to oxygen in lower partial pressure in placenta - at low partial pressure of oxygen, adult Hb will dissociate

Question 35

How to draw curve for Bohr shift?

Answer 35

- to the right of dissociation curve of adult haemoglobin - starts from 0% - sigmoid shape

Question 36

Benefits of Bohr shift to actively respiring tissue?

Answer 36

- requires more oxygen - it produces more CO2 - so Hb involved in transport of CO2 - so less Hb available to combine with CO2 so more oxygen released

Question 37

Roles of sinoatrial node + atrioventricular node in cardiac cycle?

Answer 37

- SAN is a pacemaker which initiates the heart beat - sends impulse over atria walls - AVN delays impulse - AVN sends impulse down bundle of His along Purkyne fibres

Question 38

Ways in which wall of artery is different from wall of vein?

Answer 38

- thicker - no valves - endothelium is folded - more elastic tissue - more collagen

Question 39

How high hydrostatic pressure of blood is generated in the heart?

Answer 39

Ventricular systole

Question 40

Why hydrostatic pressure of blood drops as blood moves away from heart?

Answer 40

- more vessels - vessels have larger cross sectional area - loss of plasma from capillaries - reduced resistance to blood flow

Question 41

What happens to blood plasma at arterial end of capillary?

Answer 41

- hydrostatic pressure of capillary greater than water potential - plasma moves out of blood down pressure gradient to form tissue fluid - proteins remain in capillary as too large to pass through capillary wall

Question 42

Type of muscle found in walls of heart chambers?

Answer 42

Cardiac

Question 43

Process that creates pressure inside heart chambers?

Answer 43

Systole

Question 44

What happens at 4th intersection?

Answer 44

- pressure in ventricle is lower than pressure in atrium | - atrioventricular valve opens + blood flows into ventricle

Question 45

Define single circulatory system?

Answer 45

-blood passes through heart once for each circulation of the body

Question 46

Define closed circulatory system?

Answer 46

Blood is maintained inside vessels

Question 47

How action of heart is initiated + coordinated?

Answer 47

- SAN acts as a pacemaker - impulse spreads over atrial wall - atrial systole - delay at AVN - impulse spreads down septum down bundle of His - ventricular systole from apex

Question 48

Why large multicellular organisms need transport system?

Answer 48

- high metabolic rate - small SA:V ratio - diffusion too slow to supply enough nutrients - to prevent waste products building up

Question 49

Full name given to trace showing electrical activity of heart?

Answer 49

Electrocardiogram | ECG

Question 50

Why is there a short delay between excitation of atria + excitation of ventricles?

Answer 50

- to allow time for atria to contract fully - to allow tome for ventricles to fill - so ventricles do not contract too early

Question 51

Purkyne tissue carries excitation wave down septum to apex of heart. Why to apex?

Answer 51

- So ventricular systole starts at apex | - to push blood upwards and so efficient emptying of ventricles

Question 52

How weak and irregular heartbeat could result in fatigue?

Answer 52

- lower bp - less oxygenated blood pumped to body - less O2 for oxidative phosphorylation in aerboic respiration - less ATP produced

Question 53

Fluid found in gas exhange tubes for insects?

Answer 53

tracheal fluid

Question 54

Why need well developed transport systems?

Answer 54

- high metabolic rates - small SA:V ratio - diffusion not sufficient to maintain steep conc gradient

Question 55

How refreshing the air in air sacs helps to maintain step con gradient?

Answer 55

- increases conc of o2 - so conc of O2 higher than that in blood - decreases conc of CO2 - so conc of CO2 lower than that in blood

Question 56

One way steep diffusion gradient is maintained?

Answer 56

-o2 binds with haemoglobin to keep conc in blood low

Question 57

How artery adapted to withstand pressure?

Answer 57

- wall is thick - thick layer of collagen - which provides strength - endothelium folded

Question 58

How artery adapted to maintain high hydrostatic pressure?

Answer 58

- elastic fibres to cause recoil | - thick layers of smooth muscle to constrict lumen

Question 59

What causes fluctuation in pressure as blood flows along aorta?

Answer 59

- systole increases pressure | - diastole decreases pressure

Question 60

Why important that pressure changes as blood flows from aorta to capillaries?

Answer 60

- capillary wall only 1 cell thick | - high pressure would damage the capillary wall