Blood - Mod. 2 Flashcards
What type of tissue is blood?
Connective tissue
What are the two main components of blood?
- Formed elements - cells and cells fragments
- Plasma - intercellular matrix
What makes blood unique among other tissues?
It is the only liquid tissue in the body.
How much blood volume does an adult human have?
About 5 liters.
What percent of body weight does blood make up?
8%
How does blood change color with oxygen levels?
It is bright red in color when oxygenated (in the arteries) and darker red in color when deoxygenated (in the veins).
What is the normal pH range of blood?
7.35 - 7.45
What is the temperature of blood compared to body temperature?
Blood is slightly warmer than the rest of the body, at 38 degrees C.
What are the functions of whole blood?
Transportation, regulation, and protection.
What are the main substances transported by blood?
It carries nutrients, oxygen, and water to the cells of the body and carries waste products and carbon dioxide away.
It also transports hormones to target cells throughout the body.
How does blood regulate the body?
It helps regulate body temperature, pH, the ion composition of interstitiial body fluids, and cell water content.
What role does blood play in protecting the body?
It protects the body against disease and infection, and it also protects the body against excessive blood loss through clotting.
What percent of blood plasma is water?
91.5%
What is the majority of substances found in blood plasma?
Proteins, which are transported within the plasma.
What are the four main types of plasma proteins?
- Albumins
- Fibrinogens
- Globulins
- Enzymes
What is the primary function of albumins?
They act as a blood buffer, helping to keep the pH of blood stable.
What are fibrinogens?
A family of blood clotting proteins produced by the liver.
Where are globulins produced?
In the liver and by B cell lymphocytes.
What are the two main types of globulins and their functions?
- Alpha and beta globulins - transport fat-soluble vitamins, lipids, and iron.
- Gamma globulins (immunoglobulins/antibodies) - contribute to the immunological response of the body.
What is the function of enzymes in blood plasma?
They catalyze chemical reactions and are transported to their site of action.
What are the formed elements of blood?
The cells and cell fragments found suspended within the blood plasma.
What are the three main types of formed elements?
- Red blood cells
- White blood cells
- Platelets
What is the most abundant type of cell in the body?
Red blood cells (erythrocytes)
What is the function of red blood cells?
Carry oxygen from the lungs to the tissues and return carbon dioxide from the tissues to the lungs.
What is the function of white blood cells?
They function as part of our body defense against foreign substances and pathogens entering the body, and the removal of cellular debris.
Do all white blood cells have the same function?
No, there are various different types of white blood cells, each with a specialized function.
Why must formed elements of blood be continuously replaced?
Because they have short life cycles and do not divide once mature.
How long do red blood cells typically live?
About 120 days.
What happens to red blood cells after 120 days?
They become less efficient at oxygen transport and are more prone to damage.
How does mechanical stress affect red blood cells?
As they pass through narrow capillaries, red blood cells experience wear and tear, contributing to their eventual breakdown.
Where are old or damaged red blood cells removed from circulation?
Primarily by the spleen and liver, where they are broken down, and their components (such as iron) are recycled for the production of new red blood cells.
What is hemopoiesis (hematopoiesis)?
The process of blood cell production, where the formed elements of blood develop.
Where does blood cell formation occur after birth and throughout life?
In the red bone marrow.
Where does blood formation begin in the developing embryo?
In the yolk sac.
Where does blood formation take place before bones develop?
In the liver and spleen.
When does blood formation shift to the red bone marrow?
As bones calcify and the medullary cavity of bones form.
What are originator cells and what do they do during hematopoiesis?
A hematopoietic stem cell that develops into a precursor (blast) cell, which go through several cell divisions and changes before becoming a fully mature blood cell.
What is erythropoiesis?
Red blood cell production.
What is leukopoiesis?
White blood cell production.
What is thrombopoiesis?
Platlet production.
Where does erythropoiesis occur in adults?
In the bone marrow of the sternum, vertebrae, ribs, base of the skull, and the proximal ends of the long bones.
What is a reticulocyte?
An immature red blood cell containing ribosomes and rough endoplasmic reticulum.
How long does it take for reticulocytes to mature into erythrocytes?
About two days after being released into the bloodstream.
Why are mature erythrocytes not considered true cells?
Because they lack a nucleus.
What percentage of reticulocytes make up erythrocytes in the blood?
About 1%
What is the origin of all white blood cells?
Multipotent stem cells (hemocytoblasts) in red bone marrow.
What are myeloid stem cells?
They are derived from multipotent stem cells in red bone marrow that differentiate into myeloblasts and monoblasts. Giving rise to neutrophils, eosinophils, basophils,
and monocytes.
What are lymphoid stem cells?
They are derived from multipotent stem cells in red bone marrow that differentiate into lymphoblasts, but migrate to lymphatic tissue before completing their differentiation into lymphocytes.
What do myeloblasts differentiate into?
Eosinophils, neutrophils, basophils
What do monoblasts differentiate into?
Monocytes, which ultimately become macrophages.
What do lymphoblasts differentiate into?
T lymphocytes, natural killer cells, and B lymphocytes (which become plasma cells).
Where are mature granulocytes stored?
In the bone marrow.
How many more granulocytes are stored in bone marrow compared to the blood?
10-20 times more
What are granulocytes?
A term for three types of white blood cells: neutrophils, eosinophils, and basophils.
How do granulocytes fight infection?
They contain granules that destroy germs.
What do hemopoietic growth factors regulate?
They regulate the proliferation and differentiation of hematopoietic progenitor cells in the bone marrow.
What are hematopoietic progenitor cells (HPCs) developed from?
Hematopoietic stem cells (HSCs)
Where are hematopoietic progenitor cells primarily found?
In bone marrow and blood
What types of blood cells can hematopoietic progenitor cells produce?
- Red blood cells
- White blood cells
- Platelets
Name three types of hemopoietic growth factors.
- Erythropoietin
- Thrombopoietin
- Cytokines
What triggers the synthesis and secretion of erythropoietin?
Hypoxia or low red blood cell count following blood loss
Where is erythropoietin synthesized and secreted?
By the kidneys and liver
What is the target of erythropoietin in the body?
Red bone marrow
What process does erythropoietin stimulate in proerythroblasts?
proliferate and differentiate into erythrocytes at a faster rate.
What effect does erythropoietin have on reticulocyte count?
Increases reticulocyte blood count
What is the function of thrombopoietin?
Stimulates the development of megakaryocytes into platelets
Where is thrombopoietin synthesized and secreted?
By cells in the liver
What are cytokines?
Small glycoproteins that act as local hormones in blood cell regulation.
What do cytokines stimulate in the red bone marrow?
Proliferation and differentiation of progenitor cells
What are cytokines synthesized and secreted by?
- Red bone marrow cells
- Endothelial cells
- Leukocytes
- Macrophages
- Fibroblasts
What are the most abundant cells in the body?
Erythrocytes (red blood cells)
What is the shape of red blood cells?
Thin, disc-shaped cells, with a depression in the middle on both sides.
What is the importance of red blood cells shape and size?
Their shape increases surface area to allow efficient diffusion of gases, and they are small and flexible enough to squeeze through tiny capillaries.
What are absent in red blood cells to leave more space for hemoglobin?
They do not have a nucleus and are absent of most organelles.
What do red blood cells exchange oxygen for in the tissues?
Oxygen is exchanged in the tissues for the waste product carbon dioxide.
What is hemoglobin?
A molecule consisting of a protein called globin, made up of four polypeptide chains, and an organic molecule, heme, with an iron at the center, which weakly binds reversibly to oxygen molecules.
What does each hemoglobin molecule bind?
Binds four oxygen molecules, one bound to each iron ion.
What is carbon dioxide transported as in red blood cells?
Bicarbonate (HCO 3-)
What is the enzyme carbonic anhydrase?
An enzyme carried in red blood cells that works as a catalyst in the conversion of carbon dioxide to bicarbonate through the following reactions:
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
What happens when hemoglobin combines with oxygen?
It turns a bright red color, but as the oxygen is lost to the tissues of the body, it becomes dark red.
What is nitric oxide (NO), and why is it important?
It is produced naturally by the human body and plays a key role in regulating blood pressure and blood vessel health.
How does nitric oxide (NO) interact with hemoglobin?
NO binds to hemoglobin and is released in response to changes in blood flow and blood pressure.
What happens when nitric oxide (NO) is released from hemoglobin?
It triggers local vasodilation, improving blood flow and increasing oxygen supply to nearby cells.
What does nitric oxide (NO) do in blood vessels?
It is a vasodilator that helps keep arteries open and prevents plaque buildup.
Why do red blood cells have short lifecycles?
Since RBC are deficient in many cellular organelles, they are not able to repair themselves after damage.
Why do red blood cells need to continually be replaced?
To ensure the body functions efficiently.
What happens to hemoglobin after red blood cells are broken down?
Hemoglobin is split into heme and globin for recycling.
How is the globin part of hemoglobin processed?
It breaks down further into amino acids, which are released and used to synthesize other proteins.
How is the heme part of hemoglobin processed?
It is split into iron and non-iron parts.
What happens to the iron part of heme?
It binds to transferrin, then travels to the liver, where iron detaches from transferrin and attaches to other proteins, ferritin and hemosiderin, which store iron until it is needed.
What happens to the non-iron part of heme?
It is converted to biliverdin.
What determines the different classifications of blood (blood groups)?
Classified according to the presence of different genetically determined glycoproteins and glycolipid antigens on the outer surface of red blood cell plasma membranes.
What are glycoproteins called, and what do they determine?
They are called agglutinogens (antigen), and they determine which blood group red blood cells belong to.
What are the two major blood groups?
ABO blood group and Rh blood group.
What determines an individuals ABO blood group?
Based on the presence or absence of type A and type B agglutinogens.
What determines an individuals Rh blood group?
Based on the presence or absence of a specific Rh agglutinogen, known as Rh factor or the type D antigen.
What are the two main types of white blood cells?
Granulocytes and agranulocytes.
What are the three granules found within the cytoplasm of granulocytes?
Neutrophils, eosinophils, and basophils.
What are neutrophils?
The most abundant type of white blood cells, with a multi-lobed nucleus. They are the first responders to inflammation, engulf pathogens by phagocytosis and release defensins to protect against fungi and bacteria.
What are eosinophils?
A type of white blood cell with a bi-lobed nucleus, that contain histaminase, which counteracts the effects of histamine during inflammatory response.
What are basophils?
The least abundant type of white blood cells with a bi- or tri-lobed nucleus, containing heparin, histamine, and serotonin, which are inflammatory chemical messengers. They enhance inflammation and elicit allergic reactions.
What are agranulocytes?
A type of white blood cell containing large nuclei and small cytoplasmic granules not visible under a light microscope.
What are the three stages of hemostasis?
Vascular spasm, platelet plug formation, and coagulation (blood clotting).
What is hemostasis?
A physiological response that prevents localized hemorrhage, or mass blood loss, after tissue injury.
What is vascular spasm?
The contraction of the smooth muscle in the blood vessel wall, which constricts the vessel, slowing blood loss.
What is the function of a platelet plug?
It functions as a temporary seal against blood loss.
What is coagulation?
The formation of a gel like substance called a clot that is regulated by coagulation of clotting factors such as, calcium ions.
What are blood clots?
Clumps that occur when blood hardens from a liquid to a solid.
What is a thrombus?
A blood clot that forms inside one of your veins or arteries.
What is thrombosis?
Limited blood flow due to a blood clot with blood vessels.
What is an embolus?
A thrombus that breaks loose and travels from one location in the body to another.
