L24 Flashcards
Wymień wszystkie komponenty krwi należące do “fluid component (plasma)”:
small solutes (ions, nutrients, gases, hormones) larger molecules (albumin, globulins, clotting factors) z których zabierając fibrynogen otrzymujemy serum
Wymień wszystkie komponenty krwi należące do “cellular component”
red blood cells
white blood cells
platelets
Red Blood cells- quantity
These are the most abundant cells in the blood.
- about 5000 million per millilitre, slightly more in men than women
Red Blood cells- function
Their principal function is to transport O2 and CO2.
This is facilitated by the presence of haemoglobin within the cell.
Red Blood cells- anaemia
Anaemia is a condition when the O2 carrying capacity of the blood is reduced.
e.g.
• reduction in red cell numbers
• iron, folic acid or vitamin B12 deficiencies
• defective haemoglobin (sickle-cell anaemia)
Haematocrit:
- why useful
- what is it
It is useful therefore to estimate the red blood cell number.
The haematocrit ratio (Ht) is the proportion of blood made up of
cells - mainly red blood cells.
Explain how to prepare haematocrit?
After centrifugation heavier red cells settle to the bottom of the tube. The plasma remains at the top. The two layers are separated by a ‘buffy coat’ of white cells and platelets.
Normal Ht between 0.42 - 0.47,
Haemoglobin 13.5 - 15.0 g.dl-1 values are generally larger in men than women.
What is Haematocrit?
• The haematocrit is the proportion, by volume, of the blood
that consists of red blood cells.
Haematocrit: how can it also be determined?
• The heamatocrit can also be determined by a manual method using a centrifuge. When a tube of blood is centrifuged, the red cells will be packed into the bottom of the tube. The proportion of red cells to the total blood volume can then be visually measured. That is why this is sometimes referred to as the packed cell volume.
Haematocrit: however…
• However, the haematocrit measurements are usually
automated and values calculated based on the amount of haemoglobin and the average volume of the red blood cells.
Haematocrit: normal ranges are depend on:
The normal ranges for hematocrit are depend on the age and, after adolescence, the sex of the individual.
Haematocrit: The normal ranges are:
- Newborns: 55% to 68%
- One (1) week of age: 47% to 65%
- One (1) month of age: 37% to 49%
- Three (3) months of age: 30% to 36%
- One (1) year of age: 29% to 41%
- Ten (10) years of age: 36% to 40%
- Adult males: 42% to 54%
- Adult women: 38% to 46%
Lower than normal hematocrit:
• Loss of blood (traumatic injury, surgery, bleeding, and colon cancer)
• Nutritional deficiency (iron, vitamin B12, folate),
• Bone marrow problems (replacement of bone marrow by cancer,
suppression by chemotherapy drugs, kidney failure), and
• Abnormal hemaglobin (sickle cell anemia)
Higher than normal hematocrit
• High hematocrits can be seen in people living at high altitudes
• Chronic smokers
• Dehydration produces a falsely high hematocrit that disappears when
proper fluid balance is restored
• Some other infrequent causes include abuse of the drug
erythropoietin by athletes for “blood doping” purposes.
Calculation
20 μl of normal human venous blood was diluted to a final volume of 20 ml with isotonic saline solution.
A portion of the diluted blood was counted using a haemocytometer.
In a volume of 0.1 μl the number of red cells was 530 and the number of platelets was 32.
There were 7 white cells per μl . The haematocrit from the same sample of blood was 45% and the haemoglobin content was 148 g
per liter.
From this data calculate the following:
1. The number of red cells, white cells and platelets per liter of blood.
- The number of red cells, white cells and platelets per liter of blood.
To do this we need to know what is the initial dilution was.
20 μl diluted to 20 ml (2 x 10^-5 to 2 x 10^-2)
The initial dilution is10-3 i.e. 1000x
After dilution, there are:
530 red cells in 0.1μl or
5300 red cells in 1 μl. Therefore:
in 1 μl of undiluted blood there were 5,300,000 red cells (5.3 x 10^6) and in 1 liter there will be 5.3 x 10^12 red cells
.
Following the same line of reasoning there are:
32 platelets in 0.1μl or (x 10 to get to μl plus x 1000 to account for dilution)
320,000 platelets per μl or (3.2 x 10^5)
3.2 x 10^11 platelets per liter
7 white cells per μl
7,000 white cells per μl (7 x 10^3) or
7 x 10^9 white cells per liter
Calculation
20 μl of normal human venous blood was diluted to a final volume of 20 ml with isotonic saline solution.
A portion of the diluted blood was counted using a haemocytometer.
In a volume of 0.1 μl the number of red cells was 530 and the number of platelets was 32.
There were 7 white cells per μl . The haematocrit from the same sample of blood was 45% and the haemoglobin content was 148 g
per liter.
From this data calculate the following:
2. The mean cellular volume for the red cells.
- The mean cellular volume for the red cells?
as the red cells account for only 45% of the total volume each red cell must have a volume of = 0.450 ÷ 5.3 x 10^12 = 0.085 x 10^-12 litres or 85 x1 0^-15 or 85 femtolitres.
Calculation
20 μl of normal human venous blood was diluted to a final volume of 20 ml with isotonic saline solution.
A portion of the diluted blood was counted using a haemocytometer.
In a volume of 0.1 μl the number of red cells was 530 and the number of platelets was 32.
There were 7 white cells per μl . The haematocrit from the same sample of blood was 45% and the haemoglobin content was 148 g
per liter.
From this data calculate the following:
3. The amount of haemoglobin per red cell.
- The amount of haemoglobin per red cell?
All of the haemoglobin is in the red cells so each red cell has:
148 ÷ 5.3x1012 g of haemoglobin
= 28x10-12 g or
28 pg of haemoglobin
Calculation
20 μl of normal human venous blood was diluted to a final volume of 20 ml with isotonic saline solution.
A portion of the diluted blood was counted using a haemocytometer.
In a volume of 0.1 μl the number of red cells was 530 and the number of platelets was 32.
There were 7 white cells per μl . The haematocrit from the same sample of blood was 45% and the haemoglobin content was 148 g
per liter.
From this data calculate the following:
4. If each gram of haemoglobin can bind 1.34 ml of oxygen, how much oxygen can each red cell carry?
- If each gram of haemoglobin can bind 1.34 ml of oxygen, how much oxygen can each red cell carry?
Each red cell has 28 x 10-12 pg haemoglobin
each g can carry 1.34 x 28 x 10-12 ml of oxygen
= 38 x 10-12 ml or
38 x 10-15 litres or
38 femtoliters.
Blood group 0: Antigens: Antibodies: Give blood to: Receive blood from:
None
A and B
O, A, B, AB
O
Blood group A: Antigens: Antibodies: Give blood to: Receive blood from:
A
B
A and AB
A and O
Blood group B: Antigens: Antibodies: Give blood to: Receive blood from:
B
A
B and AB
B and O
Blood group AB: Antigens: Antibodies: Give blood to: Receive blood from:
A and B
None
AB
O, A, B, AB
When giving a blood transfusion it is important that the blood
groups of the donor and recipient are known, to prevent……
agglutination.
Starling’s Forces
Are pressures involved in the movement of fluids across capillary membranes.
Starling’s equation:
the net fluid movements between the compartments depends on:
- Capillary hydrostatic pressure Pc -
- Interstitial hydrostatic pressure Pi -
- Capillary oncotic pressure πc -
- Interstitial oncotic pressure πi-
1.Capillary hydrostatic pressure Pc -
the pressure that will force fluid out from the capillary
- Interstitial hydrostatic pressure Pi -
the pressure that will force fluid out from the interstitial space
- Capillary oncotic pressure πc -
the osmotic pressure that will force the fluids to enter the capillary from the interstitial space
- Interstitial oncotic pressure πi-
the osmotic pressure that will force the fluids to enter the interstitial space from the capillary
The outward force is caused by…
capillary hydrostatic pressure and interstitial oncotic pressure
the inward force is caused by…
the capillary oncotic pressure and interstitial hydrostatic pressure
Normally the outward force and the inward force is almost at equilibrium, with slight imbalance of forces in favour of …..
the outward force.
Taking the hydrostatic and oncotic pressures of the blood and interstitium into account we can predict which way fluid will move:
if this number is positive, …..
if this number is positive, it means that fluid wants to leave the capillary and enter the interstitium (ie: there is a large driving pressure trying to push fluid out of the capillary);
Taking the hydrostatic and oncotic pressures of the blood and interstitium into account we can predict which way fluid will move:
if it is negative, ….
if it is negative, it means that fluid wants to leave the interstitium and re-enter the capillary.
Starling’s Forces:
Hydrostatic and oncotic pressures are the main driving forces, there are two additional factors that must be taken into account:
- Filtration coefficient
- Reflection coefficient:
- Different capillary beds have different reflection coefficients.
Glomerular capillaries ~1 as normally no protein crosses into the glomerular filtrate, whereas hepatic
sinusoids ~0 have a low reflection coefficient as they are quite permeable to protein. This allows albumin
produced in hepatocytes to pass from these cells into the blood.
Starling’s Forces:
Filtration coefficient:
• Filtration coefficient:
based on how large and “leaky” the capillary wall is. Simply stated, if the capillary wall is large and leaky then more fluid can be filtered across it. Increased leakiness can be caused by many different things such as histamine release (i.e. allergies) or mechanical damage.
Starling’s Forces:
Reflection coefficient:
• Reflection coefficient:
that some proteins from the blood are able to cross the vessel wall into the interstitium. This effectively reduces the
oncotic pressure within the capillary, and increases the oncotic pressure within the interstitium.
Hydrostatic pressures within the capillary force water….. the
interstitium.
into
The mean value of Pc
is about …mm Hg
25
Hydrostatic pressure within blood vessels tends to cause water to … the tissue.
This leads to a difference in protein concentration between blood plasma and tissue.
As a result the oncotic pressure of the higher level of protein in the plasma tends to draw water ….. the blood vessels … the tissue
filter out into
back into
from
explain Oedema connection to The Starling Equilibrium
When filtration forces significantly exceed absorption forces an accumulation of extravascular fluid occurs
• Primary increase of hydrostatic
pressure gradient
• Congestive heart failure
Primary decrease of oncotic
pressure gradient
Liver failure,
nephrotic syndrome
extensive tissue trauma (burns)
If a blood vessel is damaged three processes act to reduce
blood loss.
- Vasoconstriction
- Platelet aggregation
- Blood coagulation
Vasoconstriction:
This is due to a contraction of the smooth muscle around
the damaged blood vessel due to physical stimulation of the
muscle.
Platelet aggregation:
What are platelet?
• Platelets are fragments of cells called megakaryocytes.
Platelet aggregation:
How does it work?
• Damage to a blood vessel causes platelets to bind to the
injury site forming a platelet plug. This is accelerated by
platelets themselves releasing several factors (i.e. ADP,
thromboxane A2) which promote further platelet aggregation.
Platelet aggregation is modulated by drugs such as….
aspirin
Przypomnienie: Haemostasis: Coagulation
A sequence of reactions that are present in an inactive state
in blood. Key is the conversion of the plasma protein
fibrinogen to fibrin
FUNCTIONS OF BLOOD: (6)
Maintenance of cellular function.
Gaseous exchange.
Delivery of other nutrients.
Carriage of hormones.
Protection against invading organisms.
Thermoregulation.
FUNCTIONS OF BLOOD:
Maintenance of cellular function.
Maintenance of cellular function.
Establishment of proper ion gradients between the intracellular and extracelluar phases.
FUNCTIONS OF BLOOD:
Gaseous exchange.
Gaseous exchange.
Carriage of O2 and CO2 between tissues & lungs.
FUNCTIONS OF BLOOD:
Delivery of other nutrients.
Delivery of other nutrients.
Between the gut, liver and kidney for absorption,
metabolism and excretion.
FUNCTIONS OF BLOOD:
Carriage of hormones.
Carriage of hormones.
Endocrine gland secretions are carried to target
tissues.
FUNCTIONS OF BLOOD:
Protection against invading organisms.
Protection against invading organisms.
Blood provides an immunological
function.
FUNCTIONS OF BLOOD:
Thermoregulation.
Thermoregulation.
Heat generated by muscles is carried to the skin.
