Blood

Question 1

What are the functions of blood?

Answer 1

Transporting materials around the body.
Maintaining body temp.
Controls pH - super important when looking at sport and exercise.
Regulates body fluid electrolytes.
Removes toxins from the body.
Regulates blood clotting.

Question 2

What are the materials transported in blood? (7)

Answer 2

Gases.
Waste Products.
Hormones.
Enzymes.
Nutrients.
Plasma Proteins.
Blood Cells.

Question 3

What is the normal pH in the body?

Answer 3

6.8 - 7.4

Question 4

What are the two main components of blood?

Answer 4

Plasma and Cells.

Question 5

What are the three types of cell within blood?

Answer 5

Erythrocytes - red blood cells.
Leukocytes - white blood cells.
Thrombocytes - platelets.

Question 6

What % of total body weight does blood make up?

Answer 6

about 8%.

Question 7

How many litres of blood does the body have?

Answer 7

Females - 5 litres.
Males - 5.5 litres.

Question 8

Where is the majority of the blood?

Answer 8

Vast majority of blood in the body (about 3 litres) is in the veneous part of the cardiovascular system (veins).

Question 9

How many litres of blood are in the heart and arteries?

Answer 9

About 1 litre.

Question 10

How many litres of blood are in the lungs?

Answer 10

About 1 litre.

Question 11

What is the composition of blood?

Answer 11

55% Plasma.
1% White Blood Cells = leukocytes + platelets.
44% Red Blood Cells (RBCs) = erythrocytes.

Question 12

What is plasma made up of?

Answer 12

Soluble materials - mostly water- so is lighter therefore settles at the top if blood is put in a tube.

Question 13

What is the ‘Buffy coat’?

Answer 13

The White Blood Cells are referred to as the Buffy coat.

Question 14

What is the haematocrit?

Answer 14

Represents the % of total blood volume occupied by red blood cells.

Question 15

What is the normal haematocrit in males and females?

Answer 15

Females - 42% (36.1 - 44.3%).
Males 45% (40.2 - 50.3%).

Question 16

Why is haematocrit important?

Answer 16

A decrease suggest anaemia while an increase may mean that an individual has more RBCs than normal or may suggest plasma volume has decreased, this could be as a result of severe diarrhoea during cholera.

Question 17

What % of plasma is water?

Answer 17

> 90%.

Question 18

What is thermoregulation?

Answer 18

Water in plasma is extremely important as it is able to hold heat, therefore can hold and distribute the heat metabolically generated in tissues while keeping the blood temp consistent.

Question 19

What happens to any excess heat?

Answer 19

The heat not required to maintain body temperature is lost to the environs,mnt because the blood travels so close to the skin.

Question 20

What is the most abundant organic component of plasma?

Answer 20

Plasma proteins.

Question 21

Aside from water and plasma proteins, what is the rest of plasma made up of?

Answer 21

Nutrients: glucose, amino acids, lipids, vitamins.
Waste products: creatinine, bilirubin, urea.
Dissolved gases: oxygen, carbon dioxide.

Question 22

What is electrophoresis?

Answer 22

A way of separating out the proteins in blood sample based on their electrical charge.

Question 23

What are the three main roles of Plasma Proteins?

Answer 23

Plasma proteins are involved in carrying things int he blood e.g. insulin + calcium.
Buffering process - balancing acidity and alkalinity.
Osmotic pressure influences.

Question 24

What is the primary function of erythrocytes?

Answer 24

Transporting oxygen.

Question 25

Why do erythrocytes have their indented, disc shape?

Answer 25

In order to increase surface are for diffusion of oxygen across the membrane. The thinness of the cell, specifically in the indent, also allows for rapid diffusion of oxygen.

Question 26

Why can't erythrocytes use oxygen?

Answer 26

They have no mitochondria, therefore they can transport oxygen but cannot use it.

Question 27

How many RBCs does one person have at any moment?

Answer 27

25-30 trillion RBCs.

Question 28

What is the lifespan of an erythrocyte?

Answer 28

120 days.

Question 29

Where are erythrocytes formed?

Answer 29

Bone Marrow.

Question 30

Where are erythrocytes broken down?

Answer 30

Spleen.

Question 31

How many new RBCs are made per second?

Answer 31

2-3 million.

Question 32

How many miles does an RBC travel around the vasculature during its lifetime?

Answer 32

about 700 miles.

Question 33

What is the concentration of RBCs in males and females?

Answer 33

Males --> 4.5 - 6.5 x 10^9 per ml. Females --> 3.9 - 5.6 x 10^9 per ml.

Question 34

What is the mean cell volume (MCV) of an RBC?

Answer 34

80 - 96 fl.

Question 35

What is the unit "fl"?

Answer 35

1 thousand-trillionth of a litre.

Question 36

Why is MCV an important clinical index?

Answer 36

Small RBCs (microcytic) are found in iron deficiency anaemia. Large RBCs (macrocytic) are found in folate deficiency anaemia.

Question 37

Why do Erythrocytes contain Haemoglobin?

Answer 37

Haemoglobin enables erythrocytes to transport oxygen.

Question 38

How many haemoglobin does each erythrocyte contain?

Answer 38

about 300million.

Question 39

What are the 2 components of haemoglobin?

Answer 39

The Globin Part. Four iron-containing Haem Groups.

Question 40

What is a globin?

Answer 40

A protein made up of four chains.

Question 41

What are the four forms of the globin protein?

Answer 41

Alpha. Beta. Gamma. Delta.

Question 42

What combination of globin proteins do most adults have?

Answer 42

Two Alphas and two Betas (HbA).

Question 43

What combination of global proteins do some adults (about 2.5%) have?

Answer 43

two alphas and two deltas (HbA2).

Question 44

What is a haem group.

Answer 44

Each globin molecule has one attached haem group which consists of a porphyrin ring that contains one atom of iron. Therefore 4 haem groups = 4 iron atoms.

Question 45

How does haemoglobin help transport oxygen?

Answer 45

Each iron atom can combine reversibly with one molecule of oxygen, therefore, each haemoglobin molecule can pick up four oxygen passengers.

Question 46

Why is oxygen carried in haemoglobin?

Answer 46

Oxygen is poorly soluble in plasma therefore about 98.5% of oxygen is carried around the blood in haemoglobin.

Question 47

Why does haem appear red when combined with oxygen and blue when deoxygenated?

Answer 47

Haem is a pigment, therefore its colour changes slightly depending on whether it is combined with oxygen or not.

Question 48

What two factors govern haemoglobin's ability to bind with oxygen?

Answer 48

The partial pressure of O2 (pO2). The number of free )2 binding sites available in the molecule.

Question 49

What is Oxyhaemoglobin?

Answer 49

The name given when oxygen is bound to haemoglobin.

Question 50

Why is it harder to breathe at higher altitudes?

Answer 50

Because the partial pressure of the Oxygen is lower at higher altitudes.

Question 51

Describe the relationship between partial pressure and breathing difficulty.

Answer 51

At the pO2 found in the lungs, haemoglobin is nearly 100% saturated with Oxygen, this makes it easier to breathe, At the pO2 found in resting tissues, only 25% of the O2 has been released. However, during exercise, tissue pO2 will fall and haemoglobin will release more oxygen therefore requiring more oxygen = more breathing.

Question 52

Why is it easier for O2 molecules to bind to Hb once one has bound?

Answer 52

The shape of the Hb molecule alters slightly when the first O2 binds therefore making it easier for others to bind.

Question 53

What else does Hb bind to?

Answer 53

Carbon Dioxide (CO2). The acidic hydrogen portion (H+) of carbonic acid. Carbon monoxide.

Question 54

Why does Hb bind to CO2?

Answer 54

about 23% of venous blood CO2 is carried on Hb as it has different binding sites to oxygen.

Question 55

Why does Hb bind to the acidic hydrogen portion (H+) of carbonic acid?

Answer 55

H+ is generated at tissue level from CO2 so Hb buffers this acid so that large changes in blood pH are avoided.

Question 56

Why does Hb bind to Carbon Monoxide (CO)?

Answer 56

CO is not normally in the blood however, if it is inhaled, Hb will preferentially bind to it creating carboxyhaemoglobin, this is what causes carbon monoxide poisoning.

Question 57

What is a Haemoglobinopathy?

Answer 57

When abnormal globin chains are made which leads to sickles cell anaemia.

Question 58

What causes Sickle Cell Anaemia?

Answer 58

the gene encoding the beta chain of Hb is mutated, a glutamic acid is replaced by valine. this means that the resulting Hb that is formed (HbS) polymerises at low pO2 levels forming long crystals of HbS. This causes RBCs to deform and become sickle-shaped.

Question 59

What is the danger of Sickle Cell Anaemia?

Answer 59

The deformed RBCs become trapped in small vessels and block them, depriving downstream tissues of oxygen and causing ischemia and infarction.