Blood Flashcards
Name of the system that blood is part of
Haemopoietic system
Temperature of blood at rest
About 38oC
Reasons why blood temperature may exceed 40oC
Prolonged exercise
Fever
Comparison of blood to water
5 times more viscous than water
pH of blood at rest
Slightly alkaline
Around 7.4 (7.35 - 7.45)
pH of blood during high intensity exercise
Lower than normal
Can be as low as 6.7
Acidic
What percentage of body mass is blood volume
Around 7%
Components to cardiovascular system and their general role
Heart
- The pump
Blood vessels
- The conductive system
Blood
- The fluid medium
Functions of blood
Transport
Regulates body temperature
Buffers and balances acid base
Defends against pathogens and toxins
Restricts fluid loss at injury sites
Hydrolic functions….. (reproduction)
Why does blood pH change during exercise
Acetic acid built up
This lowers the pH of the blood making it more acidic
Blood distrubution rate at rest
5L/min
Blood distrubution rate during exercise
20-40L/min
Where is the majority of blood at any given time
In the veins
Venipuncture
Phlebotomy
When whole blood is taken a superficial vein
Reasons for using venipuncture to take blood
Superficial veins are easy to locate
They have thinner walls then arteries
Have lower blood pressure which allows quick wound sealing
Other areas used to take blood
Tip of the finger
Ear
Toe
Heel
Why are blood samples taken
Can check almost anything with a blood test
Blood goes everywhere and comes into contact with every part of the body
Why do veins have thinner walls than arteries
Deal with less pressure
Serum
Plasma without the clotting factors
Amount of plasma in blood
46-63%
Pecentage of formed elements in blood
37-54%
Plasma
Transport medium
Carries plasma proteins and other things like glucose
Mainly H2O
Percentage of plasma that is water
92%
Formed elements in blood
Red blood cells
White blood cells
Platelets
White band when spun in a centrafuge between plasma and red part is white blood cells and platelets
Haematocrit definition
Medical term
Describes the percentage of cellular elements in the total blood volume
Normal haematocrit values
Men - 40-52%
Women - 36-48%
Polycythaemia
Excess red blood cell production
Used of measuring haematocrit values
Can give information for the diagnosis of polycythaemia
Other name for red blood cells
Erthrocytes
Red blood cells
Highly specialised
Contain haemoglobin
Lack most organelles
Incapable of self repair
Life span of red blood cell
120 days
How far does a red blood cell travel in it’s lifetime
700 miles
Reason for lack of organelles in red blood cells
Mitochondria would steal oxygen that is being transported
Without other organelles their energy demands are low
Why can red blood cells not repair themselves or replicate themselves
Nuclei and other organelles required have been removed to make it more effecient
Where do red blood cells get their energy from
Anaerobic respiration
Uses glucose absorbed from surrounding plasma
Percentage of reb blood cells out of all cell in the body
Makes up 1/3 of all cells
Structure of red blood cells
Bi-concave disc
Benefits of red blood cell shape
Large surface area to volume ratio aids exchange
Can stack up and fall apart quickly - stacks more effeciently travel through blood vessels just larger than RBCs
Can bend and flex to squeeze trough capilaries narrower then the RBCs normal size
Haemoglobin
Intracellular protein in red blood cells
Each contains four haeme pigment complexes
Has a complex quaternary shape
How many molecules of oxygen does one red blood cell carry
About 1 billion
Haeme
Pigment complex on haemoglobin
Interacts with oxygen to form oxyhaemoglobin
Iron-oxygen interaction is very weak so can be seperated easily without damage
Ways oxygen is transported in blood (%)
Dissolved in blood (about 1.5%)
Attached to haemoglobin (about 98.5%)
Ways carbon dioxide is transported in blood (%)
Dissolved in blood (~7%)
As bicarbonate ions by reaction with water (~70%)
Attached to haemoglobin (~23%)
What is formed when CO2 attaches to haemoglobin
Carbaminohaemoglobin
Carboxyhaemoglobin
Formed when carbon monoxide binds to haemoglobin
What percentage of carboxyhaemoglobin is required to be fatal
Other effects
50%
Seizures and comas
Anemia
When blood doesn’t have enough haemoglobin
Often treated by taking in more iron to make up for lack of haemoglobin
Fetal haemoglobin
Form of haemoglobin embryos/fetuses have
Binds more readily to oxygen than normal haemoglobin
Means the fetus can steal oxygen from the mother’s blood at the placenta
Sickle cell anemia
Genetic disease
Red blood cells become sickle shaped
Can’t carry as much oxygen
RBCs can’t bend and fit through narrow spaces anymore
RBCs stick in capillaries and cause blocks
Process where RBCs are produced
Erythropoiesis
Erythropoiesis
Occurs only in red bone marrow
Produces red blood cells
Stages of erythropoiesis
- Haemocytoblasts divide to produce myeloid stem cells
- Myeloid stem cells differentiate into proerythroblast
- Proerythroblasts proceed through erythroblast stages
- Normoblast formed
- Normoblast sheds necleus and becomes a reticulocyte
- Reticuloctyre enters blood stream
- After 24 hours in blood stream reticulocyte complete maturation and becomes a RBC
Erythropoietin
EPO
Glycoprotein
Appears in the plasma when peripheral tissue like the kidneys lack oxygen
Hypoxia
State of low tissue oxygen levels
When erythropoietin is released
During anaemia
Blood flow to kidneys declines
Oxygen content in the lungs declines
Respiratory surfaces of the lungs are damaged
Major effects of erythropoietin
Stimulates increased cell division rates in erythroblasts and in stem cells that produce erythroblasts
Speeds up maturation of RBCs by accelerating haemaglobin synthesis
What synthesises haemoglobin
Erythroblasts during erythropoiesis
Image
Red blood cell turnover
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Normal stages of red blood cell recycling
- At the end of their life they are engulfed by phagocytes
- Globular proteins broken down into component amino acids which are either released or metabolised
- Heme units stripped of iron and converted to biliverdin
- Biliverdin converted to bilirubin and released into blood stream
- Bilirubin binds to album and taken to liver to be excreted in bile
- In large intestine bilirubin broken down to urobilinogens and stercobilinogens
- Urobilinogens excreted in urine
- Stercobilinogens excreted in feces
Haemolysis
When red blood cells reputure before they can be broken down
Haemoglobin released into blood and breaks down instead of being recycled
Percentage of RBCs that haemolys each day
About 10%
Haemoglobinuria
When abnomarmally large numbers of RBCs haemolyse
Urine turns red or brown
Haematuria
Presence of intact red blood cells in urine
Happens when kidneys or vessels along the urinary tract are damaged
Biliverdin
What haeme units are converted to after their iron has been taken away
Organic compound with a green colour
Bilirubin
What biliverdin is converted into
Orange-yellow pigment
Binds to album and transported to liver
What is bilirubin broken down into
2 pigments
- Urobilinogens
- Stercobilinogens
Which product of bilirubin is excreted mainly in urine
Urobilininogens
When coming into contact with _____ the products of bilirubin break down into what
When they come into contact with oxygen:
Urobilinogens → Urobilins
Stercobilinogens → Stercobilins
What transports Fe2+ back to the bone marrow for RBC production
Transferrin in blood stream
Antigen
A substance that can trigger a protective defence response
What determines a persons blood type
The presence/absence of particular antigens on the surface of their RBCs
Antigens on human red blood cells
Genetically determined
Are glycoproteins or glycolypids
Almost 50 different antigens
3 important sufarce antigens on RBCs
A
B
Rh
Blood type A
- Surface antigen
- Antibodies
- Types that can recieve blood from
Has only type A antigens
Anti-B antigens
Can recieve from A and O
Blood type B
- Surface antigen
- Antibodies
- Types that can recieve blood from
Has only type B antigens
Anti-A antigens
Can recieve from B and O
Blood type AB
- Surface antigen
- Antibodies
- Types that can recieve blood from
Both A and B antigens
Has nither anti-A or anti-B
Can recieve from A, B, AB or O
Blood type O
- Surface antigen
- Antibodies
- Types that can recieve blood from
No surface antigens
Both anti-A and anti-B antigens
Can only recieve from O
Rh antigen
As well as A and B antigens
2 types
- Rh+
- Rh-
Other name for surface antigens on RBCs
Agglutinogens
Agglutination
When blood with antigens that don’t match your own is given to you
Antibodies attacks the “foreign” red blood cells
Causes them to clump together and finally by hemolysed
Cross-match testing
Used to test if a donors blood is compatible with the recipitant
Anti-A, anti-B and anti-D antibodies are added to seperate samples of blood
Depending on which causes agglutination tells you which type it is
Universal donnor
Blood type O
Can be given to anyone
What’s the best type of blood to give to someone who you don’t know what their blood type is and why
O-
O- has no surface antigens so wont cause an immune respone
Leukocytes
White blood cells
Do white blood cells have a nuclues
What does this let them do
Yes
Control cell function and replication
Functions of white blood cells
Defend against pathogens
Remove toxins and waste
Attacks abnormal cells
White blood cell lifespan
From a few hours to decades
Where are white blood cells produced
In the bone marrow
5 classes of leukocytes percentages
Neutrophils (50-70%)
Lymphocytes (20-30%
Monocytes (2-8%)
Eosinophils (2-4%)
Basophils (<1%)
5 classes of leukocytes
Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
Way to remember 5 classes of leukocytes
Never let monkeys eat bananas
Types of lymphoctyes
Active B-cells
T-cells
Natural killer cells
Where are white blood cells
Most time in connective tissue or in the organs of the lymphatic system
Only circulate for a brief period when injury/infection happens
How do white blood cells move
All types move by amoeboid movement
Cell pulls itself forward by rearranging bonds between actin filaments in the cytoskeleton
Requires ATP and calcium ions
Where can white blood cells go
Can go in blood stream
Hides out in connective tissue
Can also move through tissue by amoebic movement
How are white blood cells guided to pathogens?
Positive chemotaxis
Which white blood cells can perform phagocytosis
Neutrophils
Eosinophils
Monocytes
What white blood cells make up the bodies non-specific defences
Neutrophils
Eosinophils
Monocytes
Basophils
Which white blood cells make up the bodies specfic defences
Lymphocytes
T cells
Type of lymphocytes
Cell mediated immunity
Travel to target
From the thymus gland
Target of HIV for replication
B cells
Type of lymphocyte
Antibody-mediated immunity
Secretes antibodies
Natural killer cells
Type of lymphocytes
Performs immune surveilance
Lysises tumours, parasites or virally infected cells
Leukopenia
Abnormally low white blood cell count
Leukocytosis
Abnormally high white blood cell count
Normally due to an infection
Leukemia
Extremely high white blood cell count
Blood platelets
Produced in the bone marrow
No nucleus
Life of 9-12 days
Involved in blood clotting
1/3 in spleen as a potential reserve
Platelet role following an injury to a vascular wall
Release enzymes needed for clotting
Provide temporary patches in damaged vascular walls (platelet plug)
Shrink the break in the vessel wall by activating their actin and myosin filaments
Haemostasis
Clotting
4 stages
Stages of haemostasis
Vascular
Platelet
Coagulation
Clot retraction
Vascular phase of haemostasis
- Blood vessel cut
- Smooth muscle fibres contract (spasm) to slow blood loss
- Basal lasminas exposed to blood
- This triggers endothelial cells to release chemicals and hormones that help the repair process
- Endothelial cells become sticky which may cause the sides of the cuts to stick together in small blood vessels
Platelet phase of haemostasis
- Platelet plug forms within 15 seconds of injury by platelet aggregation
- Platelets stick to the sticky endothelial surface release a variety of chemicals that promote aggregation, vascular spasm, clotting and vessel repair
- Positive feeback loop produces a platelet plug that is reinforced as clotting occurs
Coagulation phase of haemostasis
Occurs 30 seconds after injury
Fibrin is manufactured
Fibrin strands form a framework that can trap red blood cells and platelets
How is fibrin produced in haemostasis
Specific clotting factors required from either
- Extrinsic pathway
- Intrinsic pathway
Activation of clotting factors activates Factor X
Factor X turns on a cascade of reactions that finally produces insoluable fibrin strands
Haemostasis
Extrinsic pathway
Quick pathway
Clotting factors come from endothlial cells in the damaged vessel wall
Haemostasis
Intrinsic pathway
Sustained pathway
Clotting factors come from circulating platelets in the blood
Clot retraction phase of haemostasis
Clot fully forms
Platelet plug contracts pulling torn edges of the blood vessel together
Prostacyclin limit the growth of the plug
Plasmin digests fibrin strands through fibrinolysis
Plasmin
Enzyme
Digests fibrin through fibrinolysis
Used in the clot retraction phase of haemostasis
Fibrinolysis
Process where fibrin is broken down
Uses the enzyme plasmin
Happens in the clot retraction phase of haemostasis