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)