M103 T2 L1

Question 1

What is oxygen’s blood solubility like?

Answer 1

it’s poorly soluble

only a small amount is directly dissolved in the water of the plasma

Question 2

Can pO2 be normal in a patient with hypoxia?

Answer 2

yes - bc there is no Hb to carry oxygen

Question 3

What is the equation for respiration in muscle tissue?

Answer 3

C6H12O6 + 6O2 = 6CO2 + 6H2O + 36 ATP

Question 4

What is the equation for anaerobic glycolysi?

Answer 4

C6H12O6 = 2 lactate + 2ATP

Question 5

What percentage of the dry weight of an RBC is Hb?

Answer 5

95%

Question 6

How many daltons is a haem group and a peptide in Hb?

Answer 6

small haem group - 616 Da

large globin peptide - 17,000 Da

Question 7

What is the structure of haem like?

Answer 7

rigid, 2D and highly coloured porphyrin ring

Question 8

How does co-operativity affect how affinity for additional uptake of o2 into Hb?

Answer 8

the allosteric effect means each subunit influences its 3 neighbours - it increases their affinity for O2 increases due to shape change

Question 9

What types of Hb do adults have?

Answer 9

HbA - 99%

HbF - 1%

Question 10

Which two factors affect Hb affinity for O2 and why?

Answer 10

increased blood CO2 and decreased blood pH

these are conditions in hard working muscles and allows Hb to lose affinity for O2 and offload it into the tissues

Question 11

How does the carbolic anhydrase reaction affect blood pH?

Answer 11

it increases co2 blood levels

so there is a decreases in blood pH

Question 12

What three modes are used to transport co2 in the blood?

Answer 12

10% dissolved
22% as carbamino
68% as HCO3-

Question 13

What happens during chloride shift?

Answer 13

a co2 mlc (in deoxy muscle) enters Hb, and reacts to make an acid and carbonates which are removed from Hb in exchange for Cl-

Question 14

What happens to chloride shift when the deoxygenated blood reaches the lungs?

Answer 14

it reverses - H+ reforms into co2 and carbonate, the latter re-enters the Hb mlc in exchange for the removal of Cl-

Question 15

What is the normal pO2 of the lungs?

Answer 15

100 mmHg

Question 16

What are the graph shapes of myoglobin and Hb?

Answer 16

Hb - sigmoidal

myoglobin - hyperbolic

Question 17

An increase in which molecules causes a Hb dissociation curve to rightward - shift?

Answer 17

co2, pH and Cl-

2,3-DPG

Question 18

How does 2,3-DPG cause rightward-shift?

Answer 18

it binds to Hb, lowering its affinity for O2

Question 19

How does HbF react to 2,3-DPG compared to maternal Hb?

Answer 19

HbF has a lower affinity for 2,3-DPG compared to maternal Hb

HbF therefore has a higher affinity for o2 instead

Question 20

Explain the graph shape of myoglobin

Answer 20

has very high affinity; small amounts of oxygen just immediately fill up the myoglobin until it’s nearly totally full. There’s very little change after a certain level

Question 21

Since normal Hb has a lower o2 affinity than myoglobin and HbF, how is it still effective?

Answer 21

a normal Hb mlc will be less avid to the o2 - will give away some of the oxygen. If that o2 just sits there, the Hb will go into EQL with the o2 concentration

However, if the Hb releases the o2 and it is then hoovered up by the myoglobin or by maternal haemoglobin, the Hb tries to get into EQL.
there’s very little oxygen in the plasma nearby because every time the Hb releases an oxygen, that oxygen is hoovered up out of the plasma and onto another bound to another molecule, either to the higher affinity, foetal haemoglobin or myoglobin.

Question 22

What are the conditions in active muscles (during exercise)?

Answer 22

O2 is low, CO2 is high
Blood is slightly acidic due to co2 and lactic acid
Temperature is higher
There is myoglobin (left-shifted saturation vs Hb)

Question 23

What happens to the different molecules in active muscles (during exercise)?

Answer 23

O2 leaves the Hb due to cooperativity
CO2 and H+ bind to Hb – shifts Hb saturation curve to the right
HCO3- leaves RBC and goes into the plasma plasma
Cl- leaves the plasma and the enters RBC (Cl- shift)

Question 24

What is the main drive to increase the respiratory rate in normal adults and how is it generated?

Answer 24

acid in the cerebrospinal fluid
H+ in the blood is slow to get into the CSF because its charged and can’t get past the cell membrane, but CO2 gas can get into the CSF
once there it reacts through the enzyme carbonic anhydrase to make carbonic acid & H+
the increased pH is detected, indicates presence of co2, not enough o2 and increases breathing rate

Question 25

Which molecule triggers an increased respiratory rate?

Answer 25

H+ low 02 = high co2 high co2 is detected by H+ in the CSF

Question 26

How is blood H+ detected

Answer 26

signal from the carotid arch

Question 27

How does the blood control breathing?

Answer 27

medullary receptors - they sample the acid from the interstitial and CSF fluid

Question 28

What are the dimensions of an rbc? | How long does an rbc survive for?

Answer 28

7x2 microns | 4 months

Question 29

What is the function of erythrocytes?

Answer 29

Bag of Hb to transport O2 and CO2 | Very flexible – fold and stack in blood vessels

Question 30

How many WBCs and RBCs are there in the body?

Answer 30

RBC - 5M | WBC - 9000

Question 31

How do we work out the haematocrit of a blood sample?

Answer 31

centrifuge the blood sample what % of the cells are more dense plasma is less dense, is pushed up to the top blood cells pushed to the bottom can tell what % of the total amount of fluid is actually pure cellular matter

Question 32

Which parts of the body does erythropoiesis occur during embryogenesis?

Answer 32

(LYSL) Lymph nodes Yolk sac Spleen Liver

Question 33

What are the four stages of development for stem cells?

Answer 33

Multipotent stem cells Multipotent progenitor cells Lineage-committed progenitor cells (commitment) Mature cells (terminal differentiation)

Question 34

Which cell type do myeloblasts develop from and what cells can they turn into? (B'N'EM)

Answer 34

originates from a common myeloid progenitor basophil neutrophil eoisonophil monocyte

Question 35

What are the different stages of erythropoiesis? (HB,CERE)

Answer 35

``` Hematoepoietic stem cell BFU-E CFU-E Erythroblasts Reticulocytes Erythrocytes (RBCs) ```

Question 36

How are reticulocyte counts used?

Answer 36

as a diagnostic tool in anaemia

Question 37

What three things have the potential to cause methaemoglobinaemia?

Answer 37

Congenital globin mutations (Hb M) Hereditary decrease of NADH Toxic substances leading to the oxidation of Fe2+

Question 38

What happens during CO poisoning?

Answer 38

Hb has an affinity for CO 250x that of its affinity for CO, so low levels of CO still completely displace O2 the pO2 remains normal, but Hb is not carrying oxygen (which is the main form of transport for O2 in the body as opposed to being dissolved in the blood the blood turns bright red) the brain is affected first - disorientation

Question 39

What are the proportions of the air mixture treatment for CO poisoning?

Answer 39

95% oxygen - tries to displace or bind to any vacated spots on the Hb that the CO2 makes available 5% co2 - makes Hb less avid for the CO; helps to temporarily knock off the CO

Question 40

How is polycythaemia vera treated?

Answer 40

venesection

Question 41

How is iron stored in the body and by what proportions?

Answer 41

65% - Hb's | 30% - intracellularly as Ferritin & Haemosiderin

Question 42

Where is iron stored in the reticulo-endothelial system? Messy BLM

Answer 42

``` Macrophages/monocytes Erythrocytes Spleen Liver Bone Marrow ```

Question 43

Why are vitamin B12 and folic acid important for rapidly dividing tissue?

Answer 43

they are essential for forming thymidine in DNA if thymidine was not generated, would cause nuclear maturation to fail so any cell type making cells quickly is very sensitive to vitamin B12 and folic acid deficiencies

Question 44

What is megaloblastic (macrocytic) anaemia caused by?

Answer 44

deficiency / malabsorption of vit B12 and folic acid increased utilization of vit B12 and folic acid poor diet

Question 45

What three things can cause increased utilization of vitamin B12 and folic acid?

Answer 45

Pregnancy haemolytic anaemia lymphoma

Question 46

How is a vitamin B12 or folic acid deficiency treated?

Answer 46

the correct vitamin Oral folic acid Intramuscular hydroxocobalamin (B12)

Question 47

What is oxygen bound to in the blood?

Answer 47

70x more is bound to Hb rather than the water in the blood

Question 48

What are the stages by which the process of chloride shift occurs?

Answer 48

there's lots of co2 mlcs present near the muscle tissue area which enters Hb mlcs Co2 + h2o (+ carbonic anhydrase) = carbonic acid decomposes into a proton and carbonate the proton binds to Hb the carbonate mlcs can accumulate in the cell which is bad band 3 allows them to leave the cell in exchange for a chloride mlc co2 near respiring muscle tissue bind to Hb

Question 49

What is the role of band 3 in chloride shift?

Answer 49

it allows carbonate mlcs accumulating in Hb mlcs to leave in exchange for Cl-

Question 50

What are the stages by which the process of chloride shift reversal occurs in the lungs?

Answer 50

far less co2 the Hb gives off the proton the carbonate in the blood re-enters the rbc and swaps for chloride chloride goes back into the blood carbonic acid is regenerated and breaks down into its reactants of co2 and water the co2 leaves the lungs

Question 51

What is the role of 2,3-DPG?

Answer 51

allows oxygen release at tissue sistes | stabilises deoxyHb by allosteric binding

Question 52

What do reticulocyte counts indicate?

Answer 52

that the bone marrow is activite and producing

Question 53

What do high reticulocyte counts indicate?

Answer 53

haemolytic anaemias (homeostatic response)

Question 54

What do low reticulocyte counts indicate?

Answer 54

something wrong with the bone marrow activity

Question 55

How are reticulocyte counts taken?

Answer 55

a machine counts cells it detects those with basophilic material in them it calculates the % of cells that have reticulocytes