Blood Flashcards
Functions of Blood
Transports O2, CO2, nutrients, hormones, wastes
Regulates pH and ion composition by absorbing and neutralizing acids
Restricts fluid loss at injury sites with clotting process
Defends against toxins and pathogens with white blood cells and antibodies
Stabilizes temperature by absorbing heat and distributing blood flow to different areas
Components of Blood
Formed elements - living cells (RBC, WBC, platelets)
Plasma - non-living matrix
Volume of blood in average man/woman?
5 – 6 liters in average male
4 – 5 liters in average female
Physical characteristics of blood include:
Blood is a sticky opaque fluid with a salty metal taste
~5 x thicker than H2O
Oxygen-rich blood is scarlet red
Oxygen-poor blood is dull red/blue
pH 7.35 – 7.45 (alkaline)
Blood temperature is slightly higher than body temperature (38°C or 100.4°F)
Blood plasma is composed of
Composed of:
90% water
7% plasma proteins
3% other solutes
Straw colored fluid – contains over 100 substances (proteins, ions, nutrients, gases, wastes)
Transports organic and inorganic molecules, formed elements, heat
Forms ~55% of whole blood volume
Blood plasma
Plasma proteins in the blood include
Albumin, Clotting proteins/factors (fibrinogen, prothrombin), Globulins
regulates osmotic pressure
keeps water in the blood stream
regulates fluid volume (small assistance with pH)
approx 60% of plasma proteins
Albumin
helps to prevent blood loss when a blood vessel is injured
Clotting proteins/factors (fibrinogen, prothrombin)
helps to prevent blood loss when a blood vessel is injured
Antibodies - help protect the body from pathogens
Lipid carriers - HDL’s and LDL’s
Globulins
Plasma solutes
Electrolytes
Na+, K+, Ca2+, Mg2+, Cl–, HCO3–, HPO4–, SO42–
Organic nutrients
Lipids, carbohydrates, amino acids
Organic wastes
Urea, uric acid, creatinine, bilirubin, ammonium ions
~45% (37–54%) of whole blood (termed Hematocrit)
Main function is to carry O2 – also transport some CO2
Erythrocytes RBC’s
Blood with oxygen bound to hemoglobin
Oxyhemoglobin – bright red
Blood with lots of hemoglobin not bound to oxygen
Deoxyhemoglobin – dark red / blue
Crucial in the body’s defense against disease
Defends the body against bacteria, viruses, parasites, tumors – can move between blood and tissues
Circulate in bloodstream for short period then migrate into loose and dense connective tissue.
Attracted to specific chemical stimuli released by damaged tissues
Surround and destroy the foreign substance by phagocytosis.
Leukocytes WBCs
2 Categories of leukocytes
Granulocytes
Granules in their cytoplasm
Include neutrophils, eosinophils, and basophils
Agranulocytes
Lack cytoplasmic granules
Include lymphocytes and monocytes (macrophages)
WBCs from most to least abundant:
Hint!
Never Let Monkeys Eat Bananas
WBCs from most to least abundant: Neutrophils Lymphocytes Monocytes Eosinophils Basophils
Most common of WBC – 50 to 70%
Life span ~12 hours
Role is phagocytosis
High quantity in exudates
Neutrophils (granulocyte)
<1% of leukocytes
Main role is release of histamine to activate inflammation
Inflammatory chemical that makes blood vessels leaky and leads to chemotaxis
Reason why you get swelling with inflammation/infection
Also releases heparin (anticoagulant) – so blood does not clot with all these extra cells
Basophils (granulocyte)
2 – 4% of leukocytes
Secrete chemicals that destroy certain parasites or allergens
Those with parasite infection or allergic reaction will have elevated eosinophil count
Eosiniphils (granulocyte)
20–40 % of leukocytes
Comprised of B-cells and T-cells (part of immune system)
Lymphocytes (Agranulocytes)
2–8 % of leukocytes
Largest of the white blood cells
Mature into dendritic cells or macrophages
Also eat up the old RBC’s
Monocytes (Agranulocytes)
_____ _____ are present in those tissues that are in contact with the external environment, such as theskinand the inner lining of the nose, lungs, stomach and intestines.
Their main function is to function as antigen presenting cells (APC).
They act as messengers between theinnateand theadaptive immune systems.
Dendritic Cells
Functions of NK cells
NK cells provide rapid responses to viral-infected cells, acting at around 3 days afterinfection, and respond totumorformation.
Typically,immune cellsdetectforeign antigens presented on infected cell surfaces, triggeringcytokinerelease, causinglysisorapoptosis.
NK cells are unique, as they have the ability to recognize stressed cells in the absence ofantibodiesand foreign antigens, allowing for a much faster immune reaction.
Functions of Mast Cells
Mast cells are present in most tissues characteristically surrounding blood vessels and nerves, and are especially prominent near the boundaries between the outside world and the internal milieu, such as theskin and mucosa of therespiratory anddigestive tract.
Contains manygranulesrich inhistamineandheparin.
Best known for their role inallergyandanaphylaxis
Also play an important protective role, being highly involved in wound healing,angiogenesis,immune tolerance, defense againstpathogens, andblood–brain barrierfunction.
Not actually cells – they are fragments of cells
They cling to broken blood vessel or tissue, thus helping to control blood loss
Needed for the clotting process
Low number means more bleeding
High number means clotting
Life span of ~9-12 days
Platelets (thromobocytes)
Hematopoiesis
Definition: blood cell (RBC, WBC, platelets) formation
Occurs in red bone marrow – common sites include skull, pelvis, ribs, sternum, heads of humerus and femur
Bone marrow produces different cells at different rates – does this based on the body needs
What stimulates stem cells in bone marrow to produce RBCs?
Erythropoietin (EPO) is released into plasma when oxygen levels are low (hypoxia) such as with:
Anemia
Declining blood flow to kidneys
Decreased O2 content of air (ex: high altitudes)
Damage to respiratory surface of lungs
Formation of White blood cells and platelets is controlled/stimulated by what?
Controlled by hormones
Colony stimulating factors (CSFs) and interleukins prompt bone marrow to generate leukocytes
Role of thymosin in maturation?
Thrombopoietin stimulates production of platelets
Hemostasis involves what three phases?
- Vascular spasms
- Platelet plug formation
- Coagulation (blood clotting)
Hemostasis
Stoppage of bleeding resulting from a break in a blood vessel
Blood clotting means that blood loss is prevented when fibrous tissue moves in and seals the hole in the blood vessel
Vascular spasms
Local contraction of smooth muscle in vessel wall (vascular spasm) reduces blood loss
Platelet plug formation
Begins with attachment of platelets to:
Sticky endothelial surfaces and basement membrane
Exposed collagen fibers
Other platelets
Clotting factors released by platelets attract more platelets to site and stick together
Coagulation
Injured tissues triggers a clotting cascade – conversion of prothrombin to thrombin (an enzyme)
Thrombin joins fibrinogen proteins into hair-like molecules of insoluble fibrin
Fibrin forms a meshwork (the basis for a clot)
Vitamins and nutrients necessary for blood clotting
Ca2+ - necessary for various steps
Vitamin K – necessary for formation of several clotting proteins
Partial thromboplastin time(PTT) -
Partial thromboplastin time(PTT) - performance indicator of the efficacy of both the “intrinsic” (now referred to as the “contact activation pathway”) and the common coagulation pathways.
Prothrombin time(PT)
Prothrombin time(PT) measures theefficacy of the extrinsic pathway (“tissue factor pathway”)
PTT and PT are used in conjunction
International normalized ratio - INR
International normalized ratio - INR is the ratio of a patient’s prothrombin time to a normal (control) sample, as the time may vary according to the test used
fibrinolysis
Process of clot dissolving is fibrinolysis
Plasmin is produced in an inactive form, plasminogen, in the liver, and circulates in the blood. Although plasminogen cannot cleave fibrin, it still has an affinity for it, and is incorporated into the clot when it is formed.
Tissue plasminogen activator (t-PA) converts plasminogen to the active plasmin, thus allowing fibrinolysis to occur.
t-PA is released into the blood very slowly by the damaged endothelium of the blood vessels, so that after several days (when the bleeding has stopped), the clot is broken down.
Define hematocrit.
the ratio of the volume of red blood cells to the total volume of blood.
an instrument for measuring this, typically by centrifugation.
Identify the two components making up whole blood, and list the composition of each.
Plasma - plasma proteins (7%), other solutes (1%), water (92%)
Formed elements -Red blood cells, White blood cells, Platelets
Components of the cardiovascular system
the CV system is a circulating transport system that includes: a pump (the heart), a conducting system (blood vessels), a fluid medium (blood)
Functions of blood
Distributes oxygen, carbon dioxide, and blood cells
Delivers nutrients and hormones
Transports wastes
Assists in temperature regulation and defense against disease
Function of blood vessels
Distribute blood around the body
Blood transports
- Oxygen from lungs to all cells.
- Carbon dioxide from cells to lungs.
- Water is wherever needed.
- Nutrients from small intestine to the cell.
- Wastes(ex: Urea) from cell to excretory organs.
- Antibodies kills bacteria.
- Hormones.
Blood regulates
Blood regulates:
pH and ion composition by absorbing and neutralizing acids
Blood restricts
Fluid loss at injury sites with clotting process
Composition of whole blood
Plasma and formed elements
Term for blood removed from body
Characteristics of whole blood
38 C (100.4 F) - slightly above normal body temp
• Viscosity: 5 X more than water
slightly alkaline, pH 7.4 (7.35-7.45)
Plasma components
plasma proteins (7%), other solutes (1%), water (92%)
Plasma Proteins
Albumins - about 60 percent of plasma proteins
Contribute to osmotic pressure of plasma
Globulins - about 35 percent of plasma proteins
Include antibodies (immunoglobulins) and transport globulins
Fibrinogen - about 4 percent of plasma proteins
Function in clotting
Interact to form large strands of fibrin
Hematocrit or packed cell volume (PCV)
Percentage of whole blood volume that is formed elements
Averages 42% (females) to 47 % (males)
Androgens (male hormones) stimulate RBC production
Estrogens (female hormones) do not
During an infection, which components of blood would be elevated?
In general, infections cause an increase in the number of white cells in circulation. That is because white cells are the infection fighters and as such, get “mobilized” like the army in response to the “attack”.
Which body organ plays the main role in producing plasma proteins?
The liver is the source of most plasma proteins.
What are the three major categories of formed elements?
Erythrocytes, leukocytes and platelets
What determines whether blood is bright red (scarlet) or dull red?
The color of blood varies with the amount of oxygen it is carrying. From most oxygen to least, the blood goes from scarlet to blue-red.
What is the role of hemoglobin in the red blood cell?
Hemoglobin transports oxygen and a small amount of carbon dioxide in the blood
Which white blood cells are most important in body immunity?
Lymphocytes are the main actors in body immunity.
If you had a severe infection, would you expect your WBC count to be closest to 5,000, 10,000, or 15,000/mm3?
Infection in the body causes an increase in WBC count, thus 15,000/mm3.
Little Lisa is pale and listless. What disorder of erythrocytes might she be suffering from?
Anemia
What is the name of the stem cell that gives rise to all formed elements?
The hemocytoblast gives rise to all formed elements.
What property of RBCs dooms them to a limited life span of about 120 days?
Lack of a nucleus; therefore, they cannot carry out transcription and translation to produce proteins (enzymes and others).
How is the production of platelets different from that of all other formed elements?
The stem cell (megakaryocyte) undergoes mitosis many times, forming a large multinucleate cell, which then fragments into platelets.
What factors enhance the risk of thrombus formation in intact blood vessels?
Inactivity, leading to blood pooling, and anything that roughens or damages the lining of a blood vessel (laceration, atherosclerosis, physical trauma).
What are the classes of human blood groups based on?
The self-antigens (agglutinogens) the RBCs bear.
What is the probable result of infusing mismatched blood?
A transfusion reaction in which the RBCs are lysed and hemoglobin enters the bloodstream, potentially leading to kidney shutdown.
Cary is bleeding profusely after being hit by a truck as he was pedaling his bike home. At the hospital, the nurse asked him whether he knew his blood type. He told her that he “had the same blood as most other people.” What is his ABO blood type?
O - Positive
What is the difference between an antigen and an antibody?
An antigen is a substance foreign to the body which activates and is attacked by the immune system. An antibody is a protein released by immune cells that binds with a specific antigen and inactivates it in some way.
How does fetal hemoglobin differ from that of the adult?
Fetal HbF has a greater ability to bind oxygen and binds it more strongly than adult HbA.
What blood-related disorders are particularly common in the elderly?
Leukemia, pernicious anemia, and clotting disorders are particularly common in the elderly.
