LO 11 Flashcards
Blood is a liquid connective tissue made up of 2 basic components: _______________
- Plasma – liquid component
- Formed elements – (cells) suspended in plasma
Describe blood plasma
- Makes up just over 50% of blood volume
- Defined as blood minus its formed elements
- ‘non-living’
- Composition = primarily water containing many dissolved substances (e.g. nutrients, O2, salts, hormones, waste products)
List the plasma proteins (most abundant solutes in plasma)
- Albumins – help thicken & maintain blood volume
- Globulins – include the antibodies that help protect against infections
- Fibrinogen – critical for blood clotting
- Prothrombin – critical for blood clotting
__________ is essentially blood plasma without the clotting factors (but still contains antibodies)
Blood serum
How much blood is in the human body?
Varies with size and gender, but roughly 4-6L (7-9% of body weight)
What is the normal pH of blood?
7.35-7.45
What are the 3 main types of formed elements in blood?
- Red blood cells (RBCs or erythrocytes) - 4.5 to 5 million per mm3 of blood*
- White blood cells (WBCs or leukocytes) - 5,000 to 10,000 per mm3 of blood*
- Platelets or thrombocytes - 300,000 per mm3 of blood*
- 1 mm3 = approximately 1 drop of blood
Describe the types of white blood cells
- Granular (have granules in cytoplasm) - Neutrophils; Eosinophils; Basophils
- Non-granular or agranular leukocytes (do not have granules in cytoplasm) - Lymphocytes; Monocytes
How often are blood cells produced?
- Continually destroyed and therefore have to be continually replaced/reproduced
- A few million RBCs manufactured each second!
How are blood cells produced?
- RBCs and WBCs are produced by two types of tissues - Myeloid tissue (red bone marrow); Lymphatic tissue
_________ is the name for the formation of blood cells
Hematopoiesis
Describe myeloid tissue (red bone marrow)
- Found mainly in adult sternum, ribs, hip bones
- Forms all types of blood cells except lymphocytes
Describe lymphatic tissue
- Found in lymph nodes, thymus, spleen
- Forms lymphocytes
Describe the structure of red blood cells
- Disk-shaped, no nuclei
- Shape increases surface area to maximize function
- 4 month ‘life span’
Describe the function of red blood cells
- Exchange of O2 and CO2 between blood & body’s cells
- Transports O2 as oxyhemoglobin
- Transports CO2 as carbaminohemoglobin
Describe anemia
- Term used to describe a variety of conditions caused by an inability of blood to carry adequate oxygen to body cells
- Can occur if there is a deficiency of red blood cells or hemoglobin (even if there are adequate numbers of RBCs)
List the types of anemia
- Hemorrhagic anemia
- Aplastic anemia
- Iron deficiency anemia
- Pernicious anemia
- Sickle cell anemia
Describe hemorrhagic anemia
Decreased RBC numbers caused by hemorrhage
Describe aplastic anemia
Decreased numbers of RBCs following destruction of hemopoietic elements in the bone marrow (e.g. due to toxins, certain drugs, high dose irradiation, chemotherapy)
Describe iron deficiency anemia
Deficiency of hemoglobin due to iron deficiency. Person will likely feel tired all the time.
Describe pernicious anemia
Deficiency of intrinsic factor; leads to decreased absorption of vitamin B12 (B12 required for RBC production)
Describe sickle cell anemia
- Severe and sometimes fatal genetic disease (especially if gene is inherited from both parents)
- Caused by an abnormal type of hemoglobin that is less soluble than normal
- Hemoglobin forms solid crystals when blood oxygen is low
- Causes RBC shape to become distorted
- RBC can no longer function properly (Fig 12-5)
Describe polycythemia
- Bone marrow produces too many RBCs leading to an abnormally high RBC count
- Blood may become too thick to flow properly
- Could result in stroke or heart attack
Describe the hematocrit test
- Common lab test - centrifuge is used to separate whole blood into formed elements and liquid fraction
- Buffy coat is WBC and platelet fraction
- Normal RBC level is about 45%
- Hydration levels can affect results (e.g. dehydration🡪 decreased total blood volume🡪RBCs same number but higher percentage of total)
What is the primary function of white blood cells?
defense/immunity
Describe neutrophils
- Most numerous type of WBC
- Phagocytosis against pathogens
Describe Eosinophils
- Weak phagocytes
- Protection against certain parasitic infections
Describe basophils
- Produce heparin, a strong anticoagulant
- Secrete histamine which is released during inflammatory reactions
Describe monocytes
- Largest WBC
- Aggressive phagocytes (due to size, can engulf larger pathogens and cancerous cells)
- Macrophages (‘large eaters’) are specialized monocytes that grow to several times their original size after they migrate out of the blood
Describe lymphocytes
- Function differently from phagocytes – via immune mechanism
- B lymphocytes - produce antibodies
- T lymphocytes - directly attack foreign cells
What is a differential white blood cell count test?
- Gives the proportions of each type of WBC as a percentage of the total WBC count
- Important information as not all disorders affect each type of WBC in the same way
- Disorders than can be detected include - Leukopenia; Leukocytosis; Leukemia
Describe Leukopenia
Abnormally low WBC count: < 5,000/mm3
Describe Leukocytosis
- Abnormally high WBC count: > 10,000/mm3
- More common than leukopenia
- Usually due to bacterial infections
Describe Leukemia (blood ‘cancers’ affecting WBCs)
- WBC count >100,000/mm3
- WBCs don’t function properly
Describe the role of platelets in blood clotting
- Injury to a blood vessel 🡪rough/damaged lining
- Clotting factors released at the injury site produce prothrombin activator
- Platelets become ‘sticky’ and accumulate at injury site 🡪 soft, temporary ‘platelet plug’
- Prothrombin activator and calcium convert prothrombin (a protein normally present in the blood) in to thrombin (a protein important to blood clotting)
- Thrombin reacts with fibrinogen (a soluble blood protein), changing it into fibrin (looks like a tangle of threads)
- fibrin, traps RBC to form a clot
Describe vitamin K’s role in coagulation
Vitamin K 🡪 Stimulates liver cells to increase synthesis of prothrombin 🡪 Faster production of thrombin 🡪 Faster clot formation
Describe the negative side of blood clotting
Clots sometimes form in unbroken blood vessels (in heart, lungs, brain, other organs), and can shut off blood supply to these vital organs, leading to life-threatening events such as strokes and heart attacks.
__________ is a stationary blood clot – stays where it formed
Thrombus
The condition of having a thrombus is called ________
Thrombosis
________ is a term used for a part of a thrombus which dislodges and circulates through the bloodstream; may block a blood vessel
Embolus
What are the 2 main types of systems by which human blood can be classified
- ABO System
- Rh System
Describe the ABO system of blood classification
- In this system, blood types are identified by ‘self’-antigens in the plasma membranes of RBCs. We are born with these self-antigens.
- Four blood types: A, B, AB and O
- The letter stands for the type of ‘self-antigen’ in the plasma membrane of the individual’s RBCs
- Recall that an antigen-antibody reaction can cause ‘agglutination’ or ‘clumping’ or ‘sticking together’. This would not be a good thing to happen to our RBCs!
Describe the Rh system of blood classification
- Considers an additional antigen – the Rh antigen
- It’s what makes a blood type ‘positive’ or ‘negative’
- Rh-positive 🡪 Rh antigen is present in plasma membrane of RBC
- Rh-negative 🡪 Rh antigen is NOT present in plasma membrane of RBC
- Follows the same principle of ABO system – e.g. avoids antibody/antigen reactions
- Important to consider in blood transfusions
- 82% of U.S. population is Rh+
What blood type is the universal donor?
- O-
- RBCs of this blood type have no antigens in their plasma membranes, so there is no danger that the A, B or Rh antibodies in the recipient’s blood will cause agglutination of the incoming RBCs (therefore O- blood can be used in emergency situations so is in high demand)
What blood type is the universal recipient?
- AB+
- RBCs of this blood type have no anti-A, anti-B or anti-Rh antibodies in its plasma, so it won’t clump the RBCs being received
There are no anti-RH antibodies naturally occurring in plasma, however ….
- Anti-Rh antibodies appear in the plasma
of Rh-negative people if Rh-positive RBCs
have been introduced into their bodies - occurs commonly in pregnancy if mother is Rh - and father is Rh positive
- During pregnancy, the mixing of mother and baby’s blood doesn’t normally occur, but there are circumstances where this may happen; then, RBCs from the Rh+ unborn baby can cross into the mother’s Rh- blood through the placenta (this sould normally happen during delivery)
- The mother’s immune system considers the baby’s Rh+ RBCs as a pathogen of sorts and so will make anti-Rh antibodies against them
- These Anti-Rh antibodies may cross back through the placenta into the baby’s blood and destroy the baby’s circulating RBCs - severe anemia
- Can be diagnosed and prevented by administration of a protein called RhoGAM which prevents the mother’s body from forming anti-Rh antibodies
When RBCs are destroyed/broken down, a substance called _________ is released and causes a baby to ‘turn’ yellow – a condition known as ________
- bilirubin
- jaundice
