Blood

Question 1

What are the functions of blood?

Answer 1

Carriage of physiologically active compounds, clotting, defence, thermoregulation, maintenance of ECF pH.

Question 2

Where is the blood found in a regular healthy person?

Answer 2

5 litres, 1L in lungs, 3L in systemic venous circulation, 1L in heart and arterial circulation.

Question 3

What makes up blood?

Answer 3

Plasma, red blood cells, white blood cells, and platelets.

Question 4

What are the different types of plasmas proteins and what do they do?

Answer 4

Albumin - binds drugs, steroid hormones, lipids, TRANSPORTATION. (Most abundant) Generates oncotic pressure.

Globulins - alpha beta and gamma(antibodies- protect from infection). TRANSPORTATION, carry lipids and fat soluble vitamins.

Fibrinogen - small fraction of total number, initiating clotting if blood vessel wall is damaged.

Always found within circulation, taking molecules/nutrients around the body.

Question 5

What is oncotic pressure?

Answer 5

Like osmotic pressure, pull of water into vessel lumen.

Water, Na and glucose (interstitial fluid) moves across capillary into plasma in vessel lumen. Helps maintain plasma volume. Capillary hydrostatic pressure favours fluid out of capillary. Plasma protein conc. favours fluid into capillary.

Question 6

What is hypoproteinaemia? Causes?

Answer 6

Abnormally low levels of circulating plasma protein. Causes: starvation, liver disease, intestinal diseases, kidney disease (plasma proteins filter through seive and are lost in urine. Lost colloid oncotic pressure.

Question 7

What is haematopoiesis?

Answer 7

Formation of blood cells, all come from a single population of stem cells in the bone marrow. Can become a non-committed stem (create myeloid cells) cell OR a lymphocyte (lymphoid cell).

Question 8

What are myeloid cells?

Answer 8

Cells that aren’t lymphocytes.

Question 9

What are RBCs (erythrocytes) ?

Answer 9

Most abundant blood cell. 120 day lifespan - spleen breaks it down. Biconcave shape, no nucleus, very flexible. Densely packed with haemoglobin, protein concerned with gas transport (oxygen). When O2 binds to haemoglobin, BRIGHT RED (fully saturated with O2). (Arterial blood)

Venus blood - Bluey reddy purple colour.

Question 10

What is erythropoiesis? What is it controlled by?

Answer 10

Red blood cell production. Controlled and accelerated by erythropoietin (formed in kidney). Increased secretion when O2 levels in kidney are low (hypoxia). Eg of negative feedback - restores oxygen delivery.

Question 11

Renal Disease

Answer 11

Kidney disease, normally coupled with anaemia. Deficient in red blood cell production.

Question 12

What are Leukocytes?

Answer 12

White blood cells, have nucleus, larger than RBCs, involved in defence.

Question 13

What are neutrophils

Answer 13

Most abundant type of white blood cells, 100 billion produced every day! If increased levels, a bacterial problem.

Question 14

What is Leukopoiesis?

Answer 14

Formation of white blood cells, controlled by CYTOKINES (proteins/peptides? A complicated process - whole family of white blood cells.

Question 15

What are cytokines?

Answer 15

Proteins/ peptides that are involved in the synthesis of white blood cells.

Question 16

Increased number of lymphocytes means?

Answer 16

Viral infection.

Question 17

What are platelets?

Answer 17

Component of blood. Membrane bound fragments of cytoplasm. Life-span of 10 days. Function: stick to damaged endothelial cells to create a bridge across a gap in a blood vessel. (Initiating blood clot). Important in allowing blood clots to form.

Question 18

What is haematocrit?

Answer 18

Blood measuring process. Measures RBCs in blood. Changes viscosity of blood.

Question 19

What is Bilirubin?

Answer 19

Breaks down RBCs, formed in liver, ‘yellow’ colour of plasma. Build up of this in blood (eg liver disease)= JAUNDICE.

Question 20

What does viscosity mean?

Answer 20

How thick/sticky blood is compared to water. Depends on haematocrit - more haematocrit increases viscosity. Thicker blood - problems, harder for heart to pump blood around. Increase in temp decreases viscosity. Flow rate reducing (sitting about) = increased opportunity for cell adhesion so increased viscosity of blood (problems faced on long haul flights etc).

Question 21

Which cells are involved in blood clotting?

Answer 21

Platelets

Question 22

What does the net movement of fluid between interstitial space and vessel lumen depend on?

Answer 22

2 things:

Blood pressure (favours movement out of vessel)

Oncotic pressure (favours movement into vessel)

Question 23

What does abnormally low levels of plasma proteins result in?

Answer 23

Hypoproteinaemia

Question 24

What is the difference between myeloid cells and lymphoid cells?

Answer 24

Lymphoid: all lymphocytes

Myeloid: all other blood cells (erythrocytes, eosinophils, basophils, monocytes, neutrophils) - come from ‘uncommitted stem cell’

Question 25

What is the difference in colour between arterial and venous blood and why?

Answer 25

Arterial - red due to fact that RBCs are oxygenated (away from heart)
Venous - blue/purple - deoxygenated RBCs (to heart)

Question 26

What hormone speeds up formation of erythrocytes?

Answer 26

Erythropoietin

Produced by kidney/liver

Question 27

What are leukocytes?

Answer 27

White blood cells

Question 28

What do platelets do?

Answer 28

Form gap between blood vessel wall (damaged wall)

Starts process of clotting cascade - essential.

Question 29

What is haematocrit?

Answer 29

Percentage of RBC compared to total blood

Separation: plasma on top, then WBCs and platelets, RBCs on bottom.

Question 30

What is bilirubin?

Answer 30

Breakdown product of RBCs

Build up causes jaundice.

Question 31

What is haemolysis?

Answer 31

Rupturing of RBCs

Release of contents into surrounding fluids.