Week 5 Lecture Flashcards
Plasma accounts for how much of the blood volume?
In adults, plasma accounts for 50% to 55% of blood volume
Plasma contains what?
Plasma contains a large number of proteins (plasma proteins).
Three types of proteins in the blood
- Albumin
- Globulin
- Clotting proteins
Most plasma proteins are produced by:
The liver
Albumin
Albumin serves as a carrier molecule for both normal components of blood and drugs.
They maintain the critical colloidal osmotic pressure (or oncotic pressure) that regulates the passage of fluids and electrolytes into the surrounding tissues
Globulins
Carrier proteins and immunoglobulins in plasma
Clotting factors or proteins
The clotting factors or proteins promote coagulation and stop bleeding from damaged blood vessels.
The most plentiful of the clotting factors:
Fibrinogen is the most plentiful of the clotting factors and is the precursor of the fibrin clot
The cellular elements of the blood are broadly classified as:
The cellular elements of the blood are broadly classified as:
Red blood cells (erythrocytes),
White blood cells (leukocytes), and
Platelets.
Most abundant cells of the blood:
Red blood cells (erythrocytes)
Erythrocytes are primarily responsible for
Erythrocytes are primarily responsible for tissue oxygenation.
Hemoglobin (Hb)
Hemoglobin (Hb) carries the gases, and electrolytes regulate gas diffusion through the cell’s plasma membrane.
Life span of erythrocyte
100 to 120 days
What qualities of erythrocyte’s help it function as a gas carrier?
- A biconcave shape
- the capacity to be reversibily deformed
What does a biconcave shape do for a rbc?
The flattened, biconcave shape provides a surface area/volume ratio that is optimal for gas diffusion into and out of the cell and for deformity.
What does reversible deformity do for rbc?
Reversible deformity enables the erythrocyte to assume a more compact torpedo-like shape, squeeze through the microcirculation (diapedesis), and return to normal
Leukocytes (white blood cells)
Leukocytes (white blood cells) defend the body against organisms that cause infection and also remove debris, including dead or injured host cells of all kinds
How are leukocytes classified by structure?
Leukocytes are classified according to structure as either
- granulocytes or
- agranulocytes
What do granulocytes include:
- neutrophils
- basophils
- eosinophils,
Are all phagocytes.
What do agranulocytes include:
- Monocytes
- immature macrophages
- lymphocytes
What is the most numerous granulocyte?
Neutrophils
Granulocytes are made up of what inside them?
Have nucleus and several lobes
many membrane bound granules
What do the granules in granulocytes contain?
These granules contain enzymes capable of killing microorganisms and catabolizing debris ingested during phagocytosis.
The granules also contain powerful biochemical mediators with inflammatory and immune functions.
Neutrophils
chief phagocytes of early inflammation.
Soon after bacterial invasion or tissue injury, neutrophils migrate out of the capillaries and into the damaged tissue, where they ingest and destroy contaminating microorganisms and debris.
Eosinophils
Eosinophils ingest antigen-antibody complexes and are induced by immunoglobulin E (IgE)–mediated hypersensitivity reactions to attack parasites
What do Eosinophil granules contain?
Eosinophil secondary granules contain toxic chemicals
Eosinophil granules also contain a variety of enzymes (e.g., histaminase) that help control inflammatory processes.
Basophils contain what kind of granules
Basophils contain cytoplasmic granules with histamine, chemotactic factors, proteolytic enzymes (e.g., elastase, lysophospholipase), and an anticoagulant (heparin)
Monocytes
immature macrophages
Platelets (thrombocytes)
irregularly shaped anuclear cytoplasmic fragments that are essential for blood coagulation and control of bleeding.
Erythropoiesis
Erythropoiesis is the development of RBCs.
What are the primary cells of the immune response?
Lymphocytes
Where do lymphocytes reside?
Most lymphocytes transiently circulate in the blood and eventually reside in lymphoid tissues as mature T cells, B cells, or plasma cells.
Hematopoiesis
Hematopoiesis is the production of blood cells.
Reticulocyte
Last immature form of RBCs
Erythropoietin
(a hormone produced primarily by the kidney that stimulates erythrocyte production)
Most steps of erythropoiesis is under what loop?
Most steps of erythropoiesis are primarily under the control of a feedback loop involving erythropoietin (EPO) and other cytokines.
Where do Erythrocytes form hemoglobin?
Erythrocytes form hemoglobin in the bone marrow.
Hemoglobin (Hb) role and definition
the oxygen-carrying protein of the erythrocyte, constitutes approximately 90% of the cell’s dry weight.
What are hemoglobins composed of?
Each Hb molecule is composed of two pairs of polypeptide chains (the globins) and four colorful complexes of iron plus protoporphyrin (the hemes)
Globins
Two pairs of polypeptide chains that make up hemoglobin
Hemes
four colorful complexes of iron plus protoporphyrin that make up hemoglobin
Are responsible for the blood’s ruby red color
What is the most common type of Hb in adults?
Hb A
What is Hb A composed of?
is composed of two α- and two β-polypeptide chains (α2β2)
What is the fetal hemoglobin?
Hb F
What is Hb F composed of?
Is a complex of two α- and two γ-polypeptide chains (α2γ2)
How many molecules of oxygen can one molecule of heme carry?
Heme is a large, flat, iron-protoporphyrin disk that is synthesized in the mitochondria and can carry one molecule of oxygen (O2).
Thus, an individual Hb molecule with its four hemes can carry four oxygen molecules.
How to iron excreted from the body?
There is no excretory mechanism for iron
When is iron toxic to human cells?
Unbound or free, iron is toxic to human cells
Iron cycle
A process of continual recycling of iron from erythrocytes
Bone Marrow
Confined in the cavities of bone and is the primary site of residence of hematopoietic stem cells (HPCs)
What are the two populations of stem cells in the bone marrow niches?
- Hematopoietic stem cells (HSCs)
- Mesenchymal stem cells (MSCs)
Extramedullary hematopoiesis
is blood cell production in tissues other than bone marrow (e.g., liver and spleen).
Extramedullary hematopoiesis is usually a sign of what?
is usually a sign of disease and can occur in pernicious anemia, sickle cell anemia, thalassemia, hemolytic disease of the newborn (erythroblastosis fetalis), hereditary spherocytosis (abnormal sphere-shaped red blood cells [RBCs]), and certain leukemias.
The body responds to reduced oxygenation in two ways:
(1) by increasing the intake of oxygen through increased respiration
(2) by increasing the oxygen-carrying capacity of the blood through increased erythropoiesis.
Role of Erythropoietin in Regulation of Erythropoiesis:
(1) Decreased arterial oxygen levels result in decreased tissue oxygen (hypoxia) that
(2) stimulates the kidney to increase production
(3) of erythropoietin. Erythropoietin is carried to the bone marrow
(4) and binds to erythropoietin receptors on proerythroblasts, resulting in increased red cell production
(5). The increased release of red cells into the circulation frequently corrects the hypoxia in the tissues. Perception of normal oxygen levels by the kidney
(6) causes diminished production
(7) of erythropoietin (negative feedback) and a return to normal levels of erythrocyte production.
Thrombopoiesis
Development of platelets
Thrombopoietin (TPO)
a hormone growth factor, stimulates the production and differentiation of megakaryocytes and is the main regulator of the circulating platelet numbers.
Where is TPO primarily produced
TPO is primarily produced by the liver and induces platelet production in the bone marrow.
Hemostasis
Hemostasis is the arrest of bleeding by formation of blood clots at sites of vascular injury.
General sequence of events in hemostasis:
- (1) vascular injury leads to a transient arteriolar vasoconstriction to limit blood flow to the affected site;
(2) damage to the endothelial cell lining of the vessel exposes prothrombogenic subendothelial connective tissue matrix, leading to platelet adherence and activation and formation of a hemostatic plug to prevent further bleeding (primary hemostasis);
(3) tissue factor, produced by the endothelium, collaborates with secreted platelet factors and activated platelets to activate the clotting (coagulation) system to form fibrin clots and further prevent bleeding (secondary hemostasis); and
(4) the fibrin/platelet clot contracts to form a more permanent plug, and regulatory pathways are activated (fibrinolysis) to limit the size of the plug and begin the healing process.
Breakdown of clot is carried out by what?
Lysis (breakdown) of blood clots is carried out by the fibrinolytic system
Anemia
Anemia is a reduction in the total number of erythrocytes in the circulating blood or a decrease in the quality or quantity of hemoglobin.
Anemias commonly result from:
(1) impaired erythrocyte production,
(2) blood loss (acute or chronic),
(3) increased erythrocyte destruction, or
(4) a combination of these three factors.
How are anemias classified?
The most common classification of anemias is based on the changes that affect the cell’s size and hemoglobin content
Anisocytosis
anisocytosis (assuming various sizes)
Poikilocytosis
poikilocytosis (assuming various shapes).
Macrocytic-normochromic anemia: Description
large, abnormally shaped erythrocytes, normal hemoglobin concentrations
Examples of Macrocytic-normochromic anemia
- Pernicious anemia:
- Folate deficiency anemia:
Microcytic-hypochromic anemia:
small, abnormally shaped erythrocytes and reduced hemoglobin concentration
Examples of Microcytic hypochromic anemia:
- Iron deficiency anemia:
- Sideroblastic anemia:
- Thalassemia
Normocytic-normochromic anemia:
normal size, normal hemoglobin concentration
Examples of Normocytic-normochromic anemia:
- Aplastic anemia
- Posthemorrhagic anemia
- Hemolytic anemia
- Sickle cell anemia
- Anemia of chronic inflammation
Classic anemia symptoms:
Fatigue
Weakness
Dyspnea
Pallor
Posthemorrhagic anemia- what type of anemia?
normocytic-normochromic anemia (NNA)
What is Posthemorrhagic anemia caused by:
caused by acute blood loss.
When does anemia from chronic blood loss occur?
Anemia from chronic blood loss occurs if the loss is greater than the replacement capacity of the bone marrow.
The anemias of diminished red cell production are called:
Macrocytic (megaloblastic) anemias.
Macrocytic (megaloblastic) anemias how are they characterized?
The macrocytic (megaloblastic) anemias are characterized by unusually large stem cells (megaloblasts) in the marrow that mature into erythrocytes that are unusually large in size (macrocytic), thickness, and volume.
Macrocytic (megaloblastic) anemias are the result of:
These anemias are the result of ineffective erythrocyte deoxyribonucleic acid (DNA) synthesis, commonly caused by deficiencies of vitamin B12 (cobalamin) or folate (folic acid).
Pernicious anemia (PA)
Pernicious anemia (PA) is a type of megaloblastic anemia and is caused by vitamin B12 deficiency.
classic symptoms of PA:
classic symptoms of PA:
weakness, fatigue, paresthesias of feet and fingers, difficulty walking, loss of appetite, abdominal pain, weight loss, and a sore tongue that is smooth and beefy red.
The skin may become “lemon yellow” (sallow), caused by a combination of pallor and jaundice.
Intrinsic Factor is secreted from where?
Secreted by gastric cells
What does Intrinsic Factor do?
F is secreted by gastric cells and forms a complex with vitamin B12 (B12-IF) in the small intestine.
Folate Deficiency Anemia
A deficiency of folic acid results in a megaloblastic anemia having the same pathologic consequences as those caused by vitamin B12 deficiency.
How do people get folate?
Humans are totally dependent on dietary intake to meet the daily requirement of 50 to 200 mg/day.
Increased amounts of folate are needed for what groups of people?
- Increased amounts are required for lactating and pregnant females.
- Alcoholics and individuals with chronic malnourishment.
How are microchromic-hypochromic anemias characterized?
The microcytic-hypochromic anemias are characterized by abnormally small erythrocytes that contain unusually reduced amounts of hemoglobin
What is the most common nutritional disorder of the microcytic-hypochromic anemias
IDA
Causes of IDA
- Dietary deficiency
- Increased requirement
- chronic blood loss
- Impaired absorption
When would manifestations of iron deficiency occur?
When serum Hgb decreased to 7 or 8 per/dL
Early symptoms of IDA
Are nonspecific
fatigue, weakness, shortness of breath, and pale earlobes, palms, and conjunctivae
As condition of iron deficiency become more severe, what are the symptoms?
Changes to structure and function of epithelial cells
Koilonychia or spoon-shaped fingernails become brittle, thin, and coarsely ridged as a result of impaired capillary circulation
cheilosis (scales and fissures of the mouth),
stomatitis (inflammation of the mouth), and
painful ulcerations of the buccal mucosa and tongue characteristic of burning (glossitis)
