Outcome 5 Hemopoietic System Flashcards
Functions of blood
- distribution (nutrients, oxygen and carbon dioxide, hormones, waste products)
- regulation (body temp and PH, and blood volume)
- defence (carries clotting agents, WBC’s and antibodies)
Characteristics of blood
- a connective tissue composed of plasma and formed elements
- denser and 5X more viscous than water
- slightly alkaline (PH 7.35-7.45)
- blood volume about 5L in adults
Components of blood
- 45% of blood volume is made up of formed elements and is known as the “hematocrit”. It is mostly comprised by erythrocytes, but also contains leukocytes and platelets
- 55% of blood volume is comprised of plasma, a sticky straw coloured fluid solution that is 91% water with over 100 different salutes mixed in
What two types of connective tissue make blood cells for the body?
1) myeloid tissue -> AKA red bone marrow. In adults it is found in the axial skeleton, shoulder and pelvic girdles. Forms all types of blood cells except lymphocytes, which is found in lymphoid tissue
2) lymphoid tissue -> found as white masses located chiefly in the lymph nodes, thymus and spleen. Makes lymphocytes
True or false: all formed elements of blood begin as stem cells known as hemocytoblasts and as they grow they differentiate into red or white blood cells
TRUE!
Erythrocytes production (erythropoiesis)
- regulated by erythropoietin (EPO) hormone levels in the blood
- EPO produced by the kidneys and liver
- when receptor cells in the kidneys detect that blood oxygen levels have fallen below normal, EPO production kicks in and rising the levels of EPO in the blood stream triggers erythropoiesis
Too low RBC count causes
Hypoxia
Too high RBC count causes
Increased viscosity of the blood
Leukocyte and platelet production is stimulated by _____
Chemical messengers
Erythrocytes (red blood cells)
- no nucleus or standard cellular organelles
- biconcave donut shaped disks
- Essentially microscopic bags of hemoglobin (a protein that binds easily with oxygen)
- entire reason for existing is to transport oxygen and carbon dioxide to and from the lungs
Leukocytes (white blood cells)
- all involved in immunity
- only formed elements that are complete cells, with all the usual organelles
- lifespan varies from a few hours to months. Most live only a few days
- include:
- NEUTROPHILS-> most common; fight bacterial infection, immune response, phagocytosis
- EOSINOPHIL-> defence against parasites; also regulate allergic reactions
- BASOPHILS-> inflammation response and heparin secretion (anticoagulant)
- MONOCYTES-> macrophages with a big appetite for viruses and other chronic infections
- LYMPHOCYTES-> (B and T, natural killer cells) NB for immunity - high WBC count may indicate: bacterial and viral infections, stress, TB, leukaemia and allergic reactions
Neutrophils
- most common
- Fight bacterial infection
- immune response
- phagocytosis
Eosinophil
- defence against parasites
- regulate allergic reactions
Basophils
- inflammatory response
- heparin secretion (anticoagulant)
Monocytes
-macrophages with a big appetite for viruses and other chronic infections