WEEK 1 - the constituents of blood

Question 1

functions of blood

Answer 1

specialed fluid connective tissue

Question 2

whole blood =

Answer 2

plasma (55%)

+

formed elements (blood cells) (45%)

Question 3

adult human blood volume

Answer 3

4-6 litres

Question 4

haematocrit

Answer 4

packed cell volume

46 in males

42 in females

Question 5

composition of blood
- plasma

Answer 5

55%

7% proteins
- albumins 58% - osmotic pressure
-globulins 38% - antibodies
- fibrinogen 4% - clotting
- enzymes, hormones, prohormones 1%
91% water
2% other solutes
- ions, nutrients, waste products, gases, regulatory substances, electrolytes

Question 6

composition of blood
- formed elements

Answer 6

platelets (250-400 thousand)

white blood cells (5-9 thousand)
- neutophils 60-70%
- lymphocytes 20-25%
- monocytes 3-8%
- eosinophils 2-4%
- basophils 0.5-1%

red blood cells (4.2-6.2 million)

Question 7

collecting blood for analysis
how?

Answer 7

by venipuncture from a superficial vein (median cubital vein or anterior surface of elbow)
- easy to locate
- vein waller thinner than arteries
- blood pressure relatively low so wound seals quickly

Question 8

collecting blood for analysis
for?

Answer 8

blood smears
testing glucose, cholesterol, haemoglobin

Question 9

collecting blood for analysis
if veins difficult to access?

Answer 9

small amounts of blood taken by puncture of a finger, ear lobe, or infant big toe or heel

Question 10

collecting blood for analysis
arterial puncture

Answer 10

used to check efficiency of gas exchange at lungs (radial artery in wrist or brachial artery at elbow)

Question 11

FUNCTIONS OF BLOOD

Answer 11

transporting dissolves gases, nutrients, hormones, metabolic wastes

regulating pH and ion composition of interstitial fluids
- by diffusion
- to absorb acids produced by active tissues

restricting blood loss at sites of injury
- platelets and clotting factors

defence against toxins and pathogens using white blood cells and antibodies

stabilising body temp
- heat redistribution
- heat loss
- warm blood to sensitive organs

Question 12

plasma
albumins

Answer 12

major plasma proteins
major contributors to plasma osmolarity
- Sucking water into blood from intertestinal fluids
- Maintains blood pressure

molecular taxis
- transport hydrophobic molecules including fatty acids, thyroid hormones and steroid hormones

Question 13

plasma
globulins - antibodies

Answer 13

aid in body defence

antigen binding regions
light and heavy chain

bivalent binding molecule
binds to one arm

Question 14

plasma
globulins (transport)

Answer 14

have pockets that allow to bind small ions, hormones and compounds that might otherwise be removed by kidneys or have low solubility in water

e.g.
hormone binding proteins
metalloproteins (e.g. transferrin)
- apoliporteins
-steroid-binding proteins

Question 15

plasma
fibrinogen

Answer 15

4% of protein in blood

Complicated structure
- Made up of 6 chains
○ 2 gamma - alpha helix and beta sheet
○ 2 beta - alpha helix and beta sheet
○ Alpha - all alpha helical

Gels blood
- Stopping blood close

soluble fibrinogen is converted into insoluble fibrin during blood clotting

Question 16

plasma
fibrin generation

Answer 16

clotting removes the clotting proteins leaving behind a fluid called serum

fibrinopeptides clipped off by enzyme thrombin leaving a sticky site for binding (polymerisation)

Question 17

plasma
other proteins

Answer 17

peptide hormones
- insulin and prolactin

glycoproteins
- thyroid stimulating hormone, follicle stimulating hormone and leutinizing hormone

plasma concentrations can rise and fall from hour to hour

Question 18

plasma expanders

Answer 18

increase blood volume temporarilt (following blood loss after injury)
e..g while they work out blood type

typically contain large carbohydrate molecules to maintain proper osmotic concentration

Question 19

red blood cells

Answer 19

make up 1/3 of all cells in human body

99.9% haematocrit

give blood its red colour (haemoglobin)

ratio
1000 red blood cells :
100 platlets :
1 wbc

Question 20

red blood cell structure

Answer 20

biconcave disc

large surface area to volume ratio

form stacks threw narrow blood vessels

bend and flex when entering small capillaries

Question 21

red blood cell composition

Answer 21

lose most organelles during differentiation

retain only the cytoskeleton

no cell division or protein synthesis

lifespan less than 120 days

obtain energy by anaerobic metabolism of glucose absorbed from the plasma (dont want to use up oxygen its carrying)

haemoglobin >95% of intracellular protein (280 million molecules per cell)r

Question 22

red blood cell primary function

Answer 22

transport of respiratory gases
- oxygen
- carbon dioxide.

4 oxygens can be carried by each haemoglobin molecules

Oxygen unloaded in tissues and replaced with carbon dioxide (to be transported out of the body)

Question 23

red blood cell
abnormal haemoglobin

Answer 23

can cause thalassemisa and sickle cell anaemia

Question 24

rbc formation and turnover

Answer 24

stem cell (hemocytoblast)
–> committed cell (proeythroblast)
phase 1: ribosome synthesis
–> early erythroblast
phase 2: hemoglobin accumulation
–> late erythroblast
–> nomoblast
phase 3: ejection of nucleus
—> reticulocyte
–> erythrocyte

Through the action of the growth factor Erythropoietin (EPO), the stem cell (hemocytoblast) commits onto red cell pathway
- In bone marrow

differentiation takes 6-8 days
damaged cells phagocytosed by macrophages of the spleen, liver and red bone marrow

Question 25

blood types

Answer 25

based on antigen-antibody responses

blood type determination by the presence or absence of integral membrane glycoproteins or glycolipids on red blood cell surface

at least 50 types that are genetically determined

ABO and Rhesus (Rh) (or type D) are the most important

Question 26

ABO blood types
group A

Answer 26

group A
- red blood cell: type A
- antibodies in plasma: anti-B
antigens in red blood cell: A antigen

Question 27

ABO blood types
group B

Answer 27

group B
- red blood cell: type B
- antibodies in plasma: anti-A
antigens in red blood cell: B antigen

Question 28

ABO blood types
Group AB

Answer 28

• red blood cell: type AB
• antibodies in plasma: none
  antigens in red blood cell: A and B antigen

Question 29

ABO blood types
Group O

Answer 29

• red blood cell: type O
• antibodies in plasma: anti A and anti B
  antigens in red blood cell: none

Question 30

ABO blood types
mixing

Answer 30

if mix blood type
antibodies attack each other
so O is the universal donor because has both

Question 31

Rhesus blood types

Answer 31

Rh(+)
Rh(-)

unlike ABO types, Rh- individual does not contain anti-Rh antibodies

antibodies only present if individual is sensitized by previous exposure to Rh+ blood (e.g. haemolytic disease of newborn)

Question 32

cross reactions in transfusions

Answer 32

clumps of red blood cells can damage tissues by blocking small vessels in kidneys, lung, heart or brain

Question 33

white blood cells

Answer 33

defend body against pathogens

remove toxins, wastes and abnormal or damaged cells

most reside in connective tissue proper or the lymphatic system

Question 34

characteristics of circulating white blood cells

Answer 34

can migrate out of the blood stream - to deal with infection

are capable of amoeboid movement

are attracted to specific chemical stimuli, a process termed chemotaxis (can move towards infection)

neutophils, eosinophils, and monocytes are capable of phagocytosis
macrophages are monocytes that have migrated out of the bloodstream and become actively phagocytic

Question 35

WBC
neutrophils

Answer 35

part of the body’s non-specific defences

50-70% of circulating WBC are neutrophils

highly mobile and first WBC to arrive at a site of injury

specialised in phagocytosing bacteria marked with antibodies or complement

lifespan 10 hours in the blood or 30 mins phagocytosing

dead neutophils form pus

2-5- lobed nucleus

Question 36

WBCs
eosinophils

Answer 36

non specific defence

2-4% of circulating WBCs

attracted to sites of injury

attack objects coated with antibodies

attack by exocytosis of toxic compounds so specialised in attacking multicellular parasites
- Release toxic substances from intracellular granules
- To attack cells to big to be phagocytosed

lifespan similar to neutophil (hours to minuted)

2-lobed nucleus

Question 37

WBCs
Basophils

Answer 37

non-specific defence

<1% of circulating WBCs

attracted to sites of injury

promote inflammation by releasing histamine to dilate blood vessels and other chemicals to attract other WBCs

lifespan not known

2-lobed nucleus

Question 38

WBCs
monocytes

Answer 38

non specific defence

2-8% of circulating WBCs

attracted to sites of injury where they become phagocytic macrophages, engulfing pathogens and debris

lifespan 1-2 days in the blood, months as marcophages

kidney bean-shaped nucleus

Question 39

WBCs
lymphocytes

Answer 39

parts of the body’s specific defence

20-40% of circulating WBCs

continually migrate from bloodstream (monitoring for any sign of infection) through peripheral tissues, and back to bloodstream; can live for decades

T cells responsible for cell-mediated immunity; either attack abnormal cells (e.g. virally-infected) or control activity of other lymphocytes

B cells responsible for humoral immunity; produce antibodies

natural killer (NK) cells responsible for immune surveillance and attack abnormal cells (e.g. cancer)

A round nucleus surrounded by a thin halo of cytoplasm

Question 40

platelets

Answer 40

made by bone marrow (megakaryocytes)

lifespan 9-12 days

clump together at sites of injury, forming a platelet plug, to prevent excessive blood loss

Question 41

origins and differentiation of blood cells

Answer 41

lymphoid stem cells for lymphocytes

myeloid stem cells for all other blood cells

all cells come about through differentiation in the bone marrow
- start as stem cells and different growth factors drive towards certain cells

Question 42

Haemostasis

Answer 42

the stopping of bleeding
i.e. the prevention of excessive blood loss upon injury

three phases:
- vasoconstriction to limit blood flow
- platelet plug formation
- coagulation (or clotting) to stabilise the platelet plug (fibriligen to fibrin network)