Lecture 21. The composition and features of blood Flashcards
What does blood pressure ensure?
- Even and efficient flow through the small capillaries.
- Low enough to prevent capillary leakage but high enough
to avoid coagulation.
What happens when the blood pressure is too low/high
Too low- oxygen, nutrients, and immune cells cannot get delivered to the tissues. Coagulation, clotting
Too high- risk of chronic events
What helps the body to maintain a relatively stable blood pressure
elasticity of blood vessels
Muscular arteries and valves provide pressurised directional
flow from lungs to tissue and organs
what organs have the highest blood flow to them
skeletal muscle, brain, kidneys(filter nutrients)
What system(blood) has no pressure and why?
venous
The high pressure in the arterials has to be differential to the low-pressure side. The significant pressure change is very important for the release of O2 and transfer of CO2 to the hemoglobin molecule
Blood moves much slower
What ensures one way blood flow in the venous system?
valves
how thick are the wall of capillaries
1 cell
what is normal blood pressure
120/80
systolic/diastolic pressure
Systolic blood pressure, the top number, measures the force the heart exerts on the walls of the arteries each time it beats.( high point)
Diastolic blood pressure, the bottom number, measures the force the heart exerts on the walls of the arteries in between beats.( low point)
Cells of the blood
erythroid( give rise to RBC), myeloid( make up WBC/ leukocytes innate immunity) lymphoid( adaptive immunity, stimulated to produce antibodies to remember the immune trigger)
all originate from the same stem cell in the bone marrow
Proteins in the blood
Albumin( made by the liver, Without enough albumin, your body can’t keep fluid from leaking out of your blood vessels.) Constitutes 50% of total blood protein. Maintains colloidal osmotic pressure. Binds and transports many small molecules, and hormones.
Hemoglobin( a protein in your red blood cells that carries oxygen to your body’s organs and tissues and transports carbon dioxide from your organs and tissues back to your lungs. )
Fibrinogen (produced by the liver. This protein helps stop bleeding by helping blood clots to form.) is 7% of blood protein. Cleaved by thrombin on coagulation.
immunoglobulins ( Immunoglobulins, also known as antibodies, are glycoprotein molecules produced by plasma cells (white blood cells)
Lipids in the blood
bound in lipoproteins
HDL, LDL, VLDL
the ratio of these is a good indicator of cardiac disease
Electrolytes in the blood
salts and minerals
(HCO3 -, Na+, Cl-, Ca++, Mg++, K+ , creatine, creatinine)
Major components of blood
- Cells
- Proteins
- Lipids bound in lipoproteins HDL, LDL, VLDL
- Electrolytes, salts and minerals (HCO3 -, Na+, Cl-, Ca++, Mg++, K+ , creatine, creatinine).
- Vitamins, hormones.
- Glucose.
How much of the blood do RBC make up
~45-50%
Smallest blood cell
Platelets
~50 times smaller than RBC
structure of leukocyte
nucleus
phagocytic granules( digest foreign bodies)
Electrophoresis
The technique of blood protein separation
Serum proteins exposed to an electric field separate into 5 distinct bands. (charges on proteins interact with the current)
Albumin- the most -vely charged
The furthest right one- antibodies
- Albumin ~ 50% of total
- Globulin ~ 40% of total
• α1, α2, β, γ (immunoglobulins)
Used commonly to identify multiple myeloma. As specific monoclonal antibodies present a thick line pattern to the right
Malignant myeloma
is a form of leukemia where a malignant lymphocyte( B cell) produces monoclonal Ig. Serum electrophoresis is used to diagnose this condition
-Lower back pain, tired
Antibodies are produced from
B lymphocytes
Immunoglobins are
antibodies. Produced by B- lymphocytes
Provide with adaptive immunity
Memory
Complement
HAPPENS INSTANTENEUOSLY
-proteolytic activation cascade that is essential for innate immunity
9 proteins that “coat” bacteria targeting them for phagocytosis. C3 is the major component. Opsonisation.
Mainly for bacteria, and not viruses
Coagulation factors
13 proteins cleaved in an ordered cascade resulting in fibrinogen -> fibrin. Ca++ is essential for coagulation.
Haemophilia
Haemophilia results from a missing component of the coagulation cascade. Factor VIII deficiency is the commonest form of hemophilia.
blood ph
7.4
Electrolyte function
Isotonicity and buffering. Blood pH is very tightly maintained at 7.4. Free Ca++ and K+ - also tightly maintained and critical for the regulation of cell membrane channels, ion pumps, and normal nerve and muscle functions such as the heart.
origin of blood cells
importance of CD34 hematopoietic stem cell
- Found in bone marrow and the blood of newborn babies
- CD34 is the antigen marker on these stem cells that exist in the bone marrow. Monoclonal antibodies can recognize these stem cells and selectively remove stem cells from blood or bone marrow. They can then be put back into the patient( eg after chemo for leukemia) and these stem cells will reproduce all the other cells.
What cells are in the adaptive system?
T & B lymphocytes
Plasma cells from B lymphocytes-→ antibodies
What cells are in the innate immune system?
Myeloblast→ basophil, neutrophil, eosinophil, monocyte→ macrophage
3 important factors that drive hematopoiesis
GM-CSF Granulocyte-macrophage colony-stimulating factor
The protein produced by macrophages, T cells, endothelial cells, and fibroblasts. Stimulates the production of neutrophils, eosinophils, basophils, and monocytes.
EPO Erythropoietin Drives production of erythrocytes
Produced mainly by the kidney during adulthood and liver in perinatal.
G-CSF Granulocyte colony-stimulating factor
Produced by many different cells. Stimulates production of granulocytes but also acts to mature neutrophils
GCSF and GMCSF are administered to re-populate white cells in leukemia patients following radio-ablation
Granulocytes
basophils, eosinophils, neutrophils and mast cells.
How does oxygenation of the blood happen in the lung?
In the alveolus( alveoli) the oxygen diffuses through the thin wall of the capillaries
Oxygen and carbon dioxide exchange
-Great area for efficient exchange in the lung
the pressure that allows this exchange in regulated by protein hemaglobin
Hemoglobin structure
4 globules(parts), each containing a heme group with an Iron( Fe2) atom in the center bonded to 4 Nitrogens N
This structure allows oxygen to bind at atm. pressure
The association and dissociation of O2 from heme is regulated by the partial pressure of O2 i.e. O2 readily associates in the lungs and dissociates in the tissues.
Cyanide action
Competes for iron, and prevents oxygen from binding to the hemoglobin
Kills by binding to another iron molecule called cytochrome C in the oxidative phosphorylation chain.
heart muscle can work and your heart stops, and that can happen in the space of about 10 to 15 seconds
Complement
3 ways it can be activated: C1 Classical( requires antibodies IgM and IgG to bind to the surface of the bacteria first before the complement binds), Lectin activation, and alternative activation
C3 complement is the most important and abundant in the blood when activated by the upstream events covalently binds to the surface of the bacteria(covers it)
- Initiation cascade, C3 → C3b( very active) binds to the bacteria. Releases factors
- Receptors on the neutrophil recognize this activated form of C3( factors: C3a, C4a, C5a)
- For Gram -ve bacteria.-the end-stage of the complement (C5 onwards) forms a lytic pore that causes some bacteria to lyse. This is the Membrane Attack Complex or MAC.
*C3 and C5 convertases are important to know- neutrophil senses them
Importance of complement
-NO COMPLEMENT- NO PHAGOCYTOSIS
Essential for innate immunity
Opsonisation
Antibody opsonization is a process by which a pathogen is marked for phagocytosis.
Deposition of complement on microbes
C3
the most abundant complement component in the serum
virulence factors
proteins produced by the microbes that inhibit the complement cascade
Thrombin
the main component of coagulation cascade
an enzyme in blood plasma which causes the clotting of blood by converting fibrinogen to fibrin.
activated by 2 different pathways( Intrinsic pathway extrinsic pathway-tissue damage)
Moscitoes and leaches produces anticoagulats that act on the thrombin to prevent fibrin formation.
Plasminogen and plasmin
plasma protein gets activated into plasmin, which is an enzyme that digests blood clots
Plasmin is often used in therapeutic setting. Some drugs activates the plasminogen at the site of the blood clot and dissolves it. TPA( tissue plasminogen activator or streprokinase)
Coagulation
proteolytic activation cascade.
There are two pathways for activation
- Intrinsic caused by contact with surfaces
- Extrinsic caused by tissue damage.
Calcium is essential
Factor X(10) in coagulation
enzyme common to both intrinsic and extrinsic pathways
the most abundant WBC
Neutrophils
3 main types of blood cells
- RBC
- WBC
- platelets
the main function of RBC
Oxygen and CO2 transport
What cell is this
Basophil
*filled with purple granules
What cell is this
Neutrophil
multilobal nucleus
What cell is this
eosinophil
-stained red + purple nucleus
what cell is this?
Monocyte
-large single nucleus
What is this cell?
Plasma cell
classical activation of the complement( 1 of the 3 ways)
requires a C1 complex to bind to the antibodies bound to the pathogen. C1 complex gets activated and produces convertases on the surface of the bacteria
C3 and C5 convertases- important
