Transport In The Blood

Question 1

What is tissue fluid?

Answer 1

A watery substance that contains oxygen, goucose and other nutrients. It bathes cells of tissues so the nutrients can diffuse into the cells. It provides cells with nutrients they require

Question 2

Explain how tissue fluid is formed

Answer 2

At the arteriole end lf capillary, hydrostatic pressure is higher than the opposing water potential gradient.
Water and other small soluble substances are forced out of the capillary via its pores, down a pressure gradient
This forms tissue fluid outside the capillaries which can now bath cells around it.
Substances inside the fluid diffuses into cells

Question 3

Explain How is tissue fluid returned into the capillaries

Answer 3

The hydrostatic pressure decreases along the capillaries die to the loss of water and increases concentration of plasma proteins
At the venule end, the inward water potential gradient is higher than the hydrostatic pressure, so water reenters the capillaries via osmosis. It now contains high carbon dioxide concentrations and lower pxugen concentrations.
Any excess tissue fluid is drained into the lymphatic system, then back to the circulatory system.

Question 4

What is the hearts role in the formation of tissue fluid?

Answer 4

The left ventricle contracts to increase the hydrostatic pressure in the arterioles, which forces water down a pressure gradient out of the capillaries.

Question 5

What is mass transport?

Answer 5

The movement of substances to and from exchange surfaces over large distances.

Question 6

What is blood and what are the main components of blood?

Answer 6

Blood is a tissue, it transports substances during mass transport.
Compondnts- red blood cells, white blood cells, platelets and plasma

Question 7

What is the role of red blood cells?

Answer 7

They trabsport oxygen from the kungs to the rest of the body, using haemoglobin

Question 8

Describe three things that blood plasma transports (where from and where to)

Answer 8

Carbon dipxide from organs to lungs
Soluble products of digestion from the small intestine to other organs
Urea from lover to kidneys

Question 9

Describe snd explain three adaptations lf red blood cells

Answer 9

Very small, meaning all RBCs are nearer to plasma membranes, which decreases the diffusion oathway for oxygen and increases the surface area to volume ratio

Biconcave shape, incraeses surface area to volume ratio even more, so rate of diffusion of oxygen is quicker.

No organelle, so there is more space for haemoglobin so more oxugen can be loaded and trabsported to respiring cells

Question 10

Red blood cells lack organelles, suggest what cellular processes they cannot go through

Answer 10

No cell division due to no nucleus or chromosomes

No active transport due to no mitochondria

No protein synthesis due to no dna for prptein coding

Question 11

What is haemoglobin and its characteristics?

Answer 11

It is the blood pigmant
It has a high affinity for oxygen
It is conjugated
It has a quaternary structure, as it contains 4 polypeptide chains
It contains haem groups that bind to 4 oxygen molecules

Question 12

What is the role of haemoglobin?

Answer 12

It has a high affinity for oxygen
Itreadily loads oxugen when in high oxugen partial pressures
Transports oxygen around the body in the blood
It then unloads oxygen when in low oxugen partial pressures, allowing oxugen to diffuse into cells

Question 13

What is percentage saturation of haemoglobin?

Answer 13

The amount of pxugen carried by haemoglobin

Question 14

What is the name for haemoglobin once it has binded to oxygen?

Answer 14

Oxyhemoglobin

Question 15

What is partial pressure of oxygena nd its units?

Answer 15

The pressure exerted by oxygen in a mixture of gases, it is a measure of oxygen’s concentration
Measured in pO2

Question 16

Ehat is an oxugen dissociation curve and what shape does oxygen show?

Answer 16

It is the grapgical reprisentation of the behaviour of haemoglobin when subjected to different partial pressures
It shows a sigmoidial shape (S shape)

Question 17

State Why does the oxugen dissocistion curve has a sigmoidial shape?

Answer 17

Due to cooperative binding.

Question 18

Explain what cooperative binding is

Answer 18

It is where the binding of the first oxugen molecule onto haemoglobin changes the tertiary and wuaternary structure of the haemoglobin, which can create other binding sites or uncover other haem groups.
This allows another oxugen to be loaded

Question 19

How does paryial pressure of oxugen effect haemoglobin

Answer 19

At higher pO2, haemoglobin has a higher affininity for oxugen, so oxugen is more readily loaded. Therefore percentage saturation in haemoglobin increases

At lower pO2 concentrations, haemoglobin has a lower affinity for oxygen, so oxygen is more readily unloaded. Percentage saturation in haemoglobin decreases

Question 20

Where in the body will haemoglobin have a high or low affinity for oxygen, and how can this be shown on a dissociation curve?

Answer 20

High affinity at the lungs, where pO2 is higher (shown at the top right of curve)
Lower affinity near respiring tissues, where pO2 is lower and oxygen is needed for aerobic respiration (shown at the bottom left lf curve)

Question 21

What is the Bohr effect?

Answer 21

Where the oxygen dissociation curve shifts to the right, meaning haemoglobin has a lower affinity for oxygen and unloads more readily

Question 22

What factprs can cause the bohr effect?

Answer 22

An increased temperature
An increased carbon dioxide concentration
A decreased pH

Question 23

In what type lf tissues is the Bohr effect most likely to take place?

Answer 23

In more active tissues, with higher metabollic rates. They will have a higher demand for oxygen, so due to the bohr effect haemoglobin can unload oxugen more readily to allow it to diffuse into respiring cells

Question 24

What hapoens when the dissociation curve shifts to the left, and why may this happen?

Answer 24

Haemoglobins affinity for oxygen increases, so it is more readily loaded.
This may happen in animals that live areas of very low pO2 condidtioms, so they can still load enough oxygen ti transport around the body to maintain a high metabollic rate.

Question 25

What is hydrostatic pressure?

Answer 25

The pressure of any fluid in an elcosed space

Question 26

Why does an increased carbon dioxide concentration cause the bohr effect?

Answer 26

It causes the pH to decrease, which causes haemoglobin to release their load of oxygen

Question 27

How can the lxugen dissociation curve moving to the right be beneficial?

Answer 27

As it means haemoglobin has an increased affinty for oxygen, so aerobic respiration can still take place even at very low pO2s