Chapter 19: Blood Flashcards
(76 cards)
1
Q
What are the main functions of the cardiovascular system?
A
- Transport gas, nutrients, hormones, & metabolic wastes
- Regulation of pH and ion composition of interstitial fluid (neutralizes lactic acid, controls Ca++ and K+ concentrations)
- Restriction of fluid loss at injury sites
- Defense against toxins and pathogens
- Stabilization of body temperature
2
Q
What are the components of the cardiovascular systems? (organs, etc)
A
Blood - transport medium: 4-6L, 38 degree celsius, pH (7.35-7.45)
Heart - muscular pump that moves blood around the body
System of tubes / vessels - arteries, veins, capillaries
3
Q
What is the body’s fluid compartments? How much of body weight is composed of fluids?
A
Total fluid 60% of body weight
40% of body weight - Intracellular fluid
20% of body weight - extracellular fluid
(extracellular fluid: 80% interstitial fluid, 20% plasma)
4
Q
What kind of tissue is blood?
A
Connective tissue: plasma + formed elements
5
Q
What makes up blood? (blood composition)
A
Plasma: 55% of blood; composition similar to interstitial fluid with addition of dissolved proteins; plasma is the liquid matrix that supports and surrounds the cells
does not contain collagen and elastin like other connective tissue matrices; blood plasma contains contains a number of dissolved proteins involved in transport and clotting, as well as dissolved gases, electrolytes, and organic nutrients
Formed elements: 45% of blood
- Erythrocytes 45%: responsible for carrying oxygen in the blood by hemoglobin (binds 4 oxygen molecules)
- Leukocytes <1%: bodies immune response; defense against pathogens and disease
- Thrombocytes <1%: blood clotting
6
Q
What is the approximate composition of leukocytes?
A
Neutrophils: the most abundant phagocyte in the blood; contain extensive lysosomes (55-70%)
Lymphocytes: involved in antibody production and the target specific immune response; only small amounts in blood the rest are lymphatic tissues (nodes, tonsils, and spleen) (20-40%)
Monocytes: Can leave the blood stream and differentiate into powerful phagocytes called macrophages (2-8%)
Eosinophils: destroy parasitic worms and immune complexes (1-4%)
Basophils: release histamine and heparin (0.5-1%)
7
Q
What are the dissolved plasma proteins?
A
- Albumin: 60% of plasma protein: the most abundant protein in the plasma is involved in transporting lipid soluble substances (i.e. fatty acids and steroid hormones) in the blood, and is produced in the liver. Responsible for the majority of the blood colloid osmotic force
- Globulin: 35% of plasma protein: includes antibodies (immunoglobins) and transport globulins produced in the liver (transport vitamins, lipids, metal ions, and hormones) e.g lipoproteins
- antibodies: specialized proteins involved in immunity; produced in lymph tissue
- fibrinogen and prothrombin: 4% of plasma protein: produced in the liver and are involved in blood clotting. Require vitamin K during synthesis
- lipoproteins: produced in the liver and involved in transporting triglycerides and cholesterol in the blood
- Hormones and enzymes: specialized functions
Source of most plasma proteins: liver
8
Q
What makes up blood plasma? (ex. gas…)
A
Gases: Small amounts of oxygen and carbon dioxide are dissolved in the blood; however RBC and bicarbonate play a more important role in gas transport
Organic nutrients and metabolic wastes:
Nutrients: monosaccharides, amino acids, and water soluble vitamins
Waste products: lactase, urea, uric acid, creatinine, and bilirubin (breakdown products from: glucose, protein, DNA/RNA, creatine phosphate, hemoglobin)
Electrolytes: ions such as Na+, K+, Ca++, H+, HCO3-, and Cl-
9
Q
What is hematocrit?
A
% of volume of blood that is formed elements
formed elements:
- platelets and white blood cells: 0.1%
- red blood cells 99.9%
average for men: 46% (as men have more skeletal muscle)
average for women: 42%
10
Q
What is the structure of red blood cells?
A
Biconcave. anucleate, no membrane bound organelles, full of hemoglobin
11
Q
What does erythrocyte production require?
A
Folic acid and Vitamin B12
12
Q
What is the function of red blood cells?
A
Transport O2 and CO2
13
Q
What is the significance of the shape of RBCs?
A
- large surface area: volume ratio = increase rapid RBC movement
- form stacks (ronleaux) that smoothly flow through narrow vessels
- bend and flex through capillaries as narrow as 4um
14
Q
What is the function of neutrophils?
A
The most abundant phagocyte in the blood, contain extensive lysosomes
15
Q
What is the function of eosinophils?
A
Destroy parasitic worms and immune complexes
16
Q
What is the function of basophils and mast cells?
A
Release histamine and heparin
17
Q
What is the function of lymphocytes?
A
involved in antibody production and the targeted specific immune response; only small amounts in blood the rest are in lymphatic tissue (nodes, tonsils, and spleen)
18
Q
What is the function of monocytes?
A
Can leave the bloodstream and differentiate into powerful phagocytes called macrophages (fixed or free)
19
Q
What is the function of platelets?
A
Anucleate cell-fragments formed from larger megakaryocytes that are involved in blood clotting
20
Q
Where do all blood cells originate from?
A
All blood cells are formed in the bone marrow of a common blood stem cell, hemocytoblast
21
Q
What happens after hemocytoblasts are differentiated?
A
Mature cells enter the circulation
22
Q
See differentiation** pg 13
A
23
Q
What cell does each leukocytes originate from? (after hemocytoblast)
A
- Neutrophils, eosinophils, basophils: hemocytoblast >myeloblasts > progranulocytes (granulocytes)
- Erythrocytes: hemocytoblast > polychromatic erythroblast > erythrocyte
- Lymphocytes: hemocytoblast > lymphoblast > lymphocyte (agranulocytes)
- Monocyte: hemocytoblast > monoblast > monocyte (agranulocyte)
- Platelet: hemocytoblast > megakaryoblast > megakaryocyte > thrombocyte
24
Q
What leukocyte undergoes additional maturation?
A
Some lymphocytes undergo additional maturation in the thymus gland (lymphoid tissue)
25
What is hemaotopoiesis?
The process by which the formed elements of blood develop
- in adults, blood cells are formed in red bone marrow from pluripotent stem cells (one stem cell becomes relevant cells in body; "multipotent stem cell"). They mature in bone marrow or lymphoid tissue
26
What is erythropoiesis?
The part of hematopoiesis that deals with the production of RBCs. Erythropoiesis increases when states of hypoxia (O2 deficiency) stimulate the kidneys to release the hormone erythropoietin (EPO)
27
What is EPO?
Erythropoietin circulates to the red marrow and speeds up the maturation and release of immature red cells
EPO prod. can also be stimulated by: thyroxine, growth hormone, testosterone (but not estrogen)
28
What are the events occurring in the red bone marrow?
Developing RBCs absorb amino acids and Fe2+ from the bloodstream and synthesize new Hb molecules
1. Cells destines to become RBCs first differentiate into proerythroblasts
2. Proerythroblasts then differentiate into various stages of cells called erythroblasts. Erythroblasts are named according to total size, amount of hemoglobin present, and size and appearance of the nucleus
3. After roughly 4 days of differentiation, the erythroblast, now called a normoblast, sheds its nucleus and becomes a reticulocyte, which contains 80 percent of the Hb of mature RBC
4. After 2 days in the bone marrow, reticulocytes enter the bloodstream. After 24 hours in circulation, the reticulocytes complete their maturation and becomes indistinguishable from other mature RBCs
29
What are reticulocytes?
A young/immature RBC
The rate of erythropoiesis is measured by the number of immature RBCs (called reticulocytes or retics) in the peripheral circulation
a low retic count (<.5%) indicates a low rate of erythropoiesis while an elevated (>2%) indicates high rate of erythropoiesis
the normal range is 1-2% of the RBCs being "retics"
RBC production requires amino acids, iron, Vitamin B, folic acid.
Low RBC or hemoglobin production leads to fatigue, weakness, and confusion due to lower O2 delivery
30
What are erythrocytes?
45% of the blood is RBC. This percentage is called the value is % of formed elements
during differentiation RBCs synthesize large amounts of the protein hemoglobin. Once hemoglobin production is complete, normoblasts eject their nucleus and organelles, and take on the shape of a biconcave disk
once differentiated the RBC cannot replicate synthesize protein, or produce ATP from aerobic pathways and only live for 120 days
31
What is hemoglobin? What is hemoglobin concentration?
A complex protein with 4 iron-containing heme groups. Each heme group can reversibly bind to one oxygen molecule; therefore each molecule of hemoglobin is capable of carrying 4 oxygen molecules
Hemoglobin concentration: roughly 110-170 grams of hemoglobin per L of blood
4 polypeptide chains, each with a heme = pigment
- the iron of each heme can bind to 1 oxygen molecule
32
What is the reversible equation for hemoglobin?
Hb + O2 <-> HbO2
(deoxyhemoglobin) <-> (oxyhemoglobin)
33
What are some conditions arising from abnormalities of erythropoiesis?
Anemia and Polycythemia
34
What is anemia?
Without oxygen carrying capacity ; a condition of insufficient RBCs or hemoglobin (quality or quantity)
- it is most often the result of low iron intake, hemolysis, autoimmune disease, blood loss, or lack of production in the bone marrow
35
What is polycythemia?
A condition of excess number of RBCs
- it occurs in response to hypoxia (natural "blood doping" is training at high altitude), shots of EPO (illegal doping), smoking (COPD) (impaired o2 delivery stimulates kidneys to secrete more EPO in compensation) or dehydration
36
What are the 4 types of anemia?
1. Iron deficiency anemia: most common anemia in the US and affects primarily menstruating women
2. Hemorrhagic anemia: the result of precipitous blood loss, and results in an equal decrease in Hct and Hgb content (hematocrit and hemoglobin), and RBC count
3. Pernicious anemia: due to low vitamin B12 in diet (or low intrinsic factor, which is required for vitamin B12 absorption (Vitamin B12 is required for folic acid uptake)
4. Sickle cell anemia: an autosomal recessive disorder. A genetic defect in the primary DNA sequence leads to production of faulty Hb Beta chain, and RBCs that take on a rigid sickle shape
- sickling decreases the cell's flexibility and results in a variety of complications; life expectancy is shortened
- treatments include: medications, blood transfusion, bone marrow stem cell replacement
37
What does RBC production require?
Iron, amino acids, vitamin B12, and folic acid
38
Erythrocyte life cycle
Erythropoiesis (RBC Formation in Bone Marrow)
New erythrocytes are formed in the red bone marrow from hematopoietic stem cells.
Erythropoietin (EPO), a hormone released by the kidneys in response to low oxygen levels, stimulates RBC production.
RBC production requires iron (Fe), amino acids, vitamin B12, and folic acid.
Circulation and Function (120-Day Lifespan)
Mature erythrocytes lack a nucleus and function primarily to transport oxygen (O₂) and carbon dioxide (CO₂) via hemoglobin.
They circulate in the bloodstream for about 120 days before aging and becoming damaged.
Aging and Breakdown (Hemoglobin Recycling)
Aged and damaged RBCs are broken down by macrophages in the liver, spleen, and bone marrow.
Hemoglobin Breakdown:
Heme → Bilirubin, which is sent to the liver, secreted into bile, and excreted in feces.
Globin → Broken into amino acids, which are reused for protein synthesis.
Iron (Fe) → Stored as ferritin or hemosiderin in the liver and bone marrow or transported via transferrin in the blood for new RBC production.
Nutrient Absorption and RBC Renewal
Iron, amino acids, vitamin B12, and folic acid are absorbed from food in the intestines and transported into the bloodstream for use in new RBC formation.
The cycle repeats as the body continuously produces new erythrocytes.
39
What happens if blood delivered to kidneys contain low O2?
1. Some stimulus disrupts homeostasis by decreasing oxygen delivery to kidneys and other tissues
2. receptors: kidney cells detect low oxygen level
input to control center; increased erythropoietin secreted into blood
3. control center: proerythroblasts in red bone marrow mature more quickly into reticulocytes
output; increased erythropoietin secreted into blood
4. effectors: large number of RBCs in circulation, increased oxygen delivery to tissues > returns to homeostasis when oxygen delivery to kidney's increases to normal
40
How does blue light help neonates in nicu?
treats neonatal jaundice (hyperbilirubinemia). It helps break down bilirubin, a yellow pigment that can accumulate in a newborn’s blood due to the immature liver’s inability to process it efficiently.
How Blue Light Therapy Works:
Bilirubin Breakdown (Photo-oxidation & Isomerization)
Makes bilirubin water soluble
These new forms can be easily excreted through urine and stool, bypassing the liver.
Prevents Kernicterus (Brain Damage from High Bilirubin)
If left untreated, severe jaundice can lead to kernicterus, a condition where bilirubin deposits in the brain, causing neurological damage, seizures, or cerebral palsy.
Blue light therapy reduces bilirubin levels and prevents brain damage.
41
What is the life span of a red blood cell>
120 days; eventually they rupture or are destroyed by immune system cells (wbc) by phagocytosis
- constantly are being replaced at a rate of 1% per day
- most often replaced by targeted phagocytosis of old RBCs by macrophages
42
What is hemopoiesis? Where does it occur?
Formation of all blood cells (RBC, WBC, platelets)
Occurs in red bone marrow in adults:
RBC formation = erythropoiesis
43
What are multipotent stem cells?
All types of blood cells develop from hemocytoblasts
44
What determines the number of each type of blood cell that is produced?
Signals that stem cells receive in the form of hormones
45
What is erythropoiesis?
Production of RBC
controlled by hormone EPO (erythropoietin) produced by cells of the kidney
regulation: tonic baseline production of erythropoietin
- tonic production of RBCs
production increased in response to low tissue O2 levels (hypoxia)
46
What are leukocytes?
WBC; have nuclei, organelles
function: non-specific and specific defense
most white blood cells are located in connective tissue proper or organs of the lymphoid system (thymus, spleen, lymph nodes)
small proportion are found circulating in the bloodstream
two groups; depending on whether they contain conspicuous chemical-filled cytoplasmic granules
1. granulocytes: neutrophils, eosinophils, basophils
2. agranulocytes: lymphocytes, and monocytes
47
What are special properties of circulating WBCs?
1. diapedesis: process of squeezing out of capillaries and entering tissue
2. amoeboid movement
3. positive chemotaxis
4. phagocytosis (neutrophils, eosinophils, monocytes)
48
What are neutrophils?
50-70% of circulating WBCs
Nucleus has 5 lobes, known as polymorphonuclear leukocytes (PMNs)
- cytoplasm contains granules (secretory vesicles)
- granules contain lysosomal enzymes and bactericidal compounds
- specializes in fighting bacteria that have been identified and flagged by components of immune system (e.g. antibodies)
- engulf and destroys bacterial cells (phagocytosis)
49
What is chemotaxis?
Chemicals released by microbes and inflamed tissues attract phagocytes, a phenomenon called chemotaxis
WBC follows chemical trail and engulfs and gets rid of pathogen
50
What are eosinsophils?
Bilobed nucleus, granules stain with red dye eosin
main role: release substances that fight multicellular pathogens (e.g. parasitic worms)
- have been associated with allergies
granules contain:
- digestive enzyme
- toxins
- chemicals that modulate the immune response
51
What are basophils?
Bilobed nucleus with granules that stain dark blue with basic stains
- granules contain histamine
- similar to mast cells in function
- migrate to site of injury and release histamine which dilates blood vessels (vasodilation)
- release heparin which prevents blood clotting
- play a role in allergies and inflammatory response along with mast cells
52
What are monocytes?
Agranulocytes, largest WBCs, and have a kidney bean shaped nucleus
- remains in blood ~24hours
- enter tissue and transform
- become macrophages (free or fixed) large phagocytic cells that patrol tissues engulf foreign materials and release substances that attract neutrophils, monocytes, and fibroblasts
- chemotaxis
53
What are lymphocytes?
Agranulocytes with large dark nucleus, little cytoplasm
= 20-30% of circulating WBCs
most located in connective tissue and lymphoid tissues
3 Types:
a) T cells: attack foreign cells (specific immune response)
b) B cells: produce antibodies (specific immune response)
c) Natural killer (NK) cells: destruction of abnormal tissue cell (e.g. cancer cells) (nonspecific immune response)
54
What are platelets?
Anucleate cell fragments produced by large cells = megakaryocytes
- their granules contain chemicals that once release play crucial role in clotting
- usually 2/3 of platelets circulating
- 1/3 platelets are stored in the spleen
- short life span as it is anucleate (5-9 days)
55
What is hemostasis? When does it occur?
Hemostasis or blood clotting occurs when there is injury to a blood vessel in 3 stages
stage 1: vascular spasms: smooth muscle contraction caused by reflex pain response and chemicals released from endothelial cells; blood vessels constrict preventing blood loss
stage 2: platelet plug formation: platelets stick to the exposed collagen from the damaged endothelium vessel. Once stuck they release serotonin and thromboxane A, which leads to further constriction and platelet aggregation, leading to a temporary plug
stage 3: coagulation: soluble fibrinogen is converted to insoluble fibrin fibers, which stabilize the blood clot. this series of events is caused by the activation of prothrombin activator (factor x) and can be achieved by intrinsic or extrinsic mechanisms
followed by clot retraction and fibrinolysis
56
What occurs during the vascular phase?
Characterized by smooth muscle vessel contraction and constriction = vascular spasm
result: minimizes blood loss while next steps take place
* endothelins: potent vasoconstrictors
triggered by direct damage to the wall of vessel, then endothelial cells
1. contract, exposing underlying collagen fibres
2. release a variety of chemical messengers (ADP, tissue factor, prostacyclin, and endothelins)
3. endothelial cell membranes become sticky
57
What are endothelins?
Potent vasoconstrictors
58
What occurs during the platelet phase?
Platelets stick to endothelial cells and exposed collagen fibers, become platelet plug and release many chemical messengers including ADP, thromboxane A2, proteins, Ca++, and platelet derived growth factor
* last stage before the healing phase
ADP: attract and activates platelet aggregation and secretion
thromboxane A2: stimulates vascular spasms
proteins: participate in clotting
Ca++: required for tissue factor and factor X
platelet derived growth factor: promotes vessel repair
Generates a positive feedback loop that results in the formation of platelet plug and clotting at the site of the damage
59
How does the body avoid an explosive positive feedback? (too much clotting)
Undamaged endothelial cells produce anticoagulants (e.g. prostacyclin)
- inhibits platelet aggregation except at site of injury
60
What occurs during the coagulation phase?
Blood clotting; involves complex chain reaction ending with conversion of the plasma protein fibrinogen (soluble) to fibrin (insoluble)
- fibrin forms meshwork over platelet plug
Caused by the activation of prothrombin activator (factor x)
- can occur through intrinsic (within the blood) or extrinsic (by damaged tissue) mechanisms
Intrinsic factors: release from platelet can activate prothrombin activator (factor X) however this process is considered **slow**
Extrinsic factors: such as tissue factor are released from damaged tissue and activate prothrombin activator (factor x) **very rapidly**
Calcium ions are required for both intrinsic and extrinsic mechanisms
61
What are clotting factors?
molecules or ions required for clotting to proceed
; includes clotting factors calcium and vitamin K
62
Difference in coagulation through intrinsic vs extrinsic mechanisms
Intrinsic factors: release from platelet can activate prothrombin activator (factor X) however this process is considered **slow**
Extrinsic factors: such as tissue factor are released from damaged tissue and activate prothrombin activator (factor x) **very rapidly**
Calcium ions are required for both intrinsic and extrinsic mechanisms
63
What occurs during fibrinolysis and regeneration?
Platelets release Platelet Derived Growth Factor (PDGF) which stimulates the damaged vessel to regenerate
- regeneration tissue release Tissue Plasminogen Activator (tPA) which converts plasminogen to plasmin (a powerful digestive enzyme) that dissolves the clot
64
What occurs during recovery of hemostasis?
Recovery:
1. Clot retraction
- occurs once platelets and RBCs entangled in fibrin mesh
- platelets contract by pulling torn edges of vessel closer together, reducing the size of damaged area
2. Fibrinolysis:
- as repairs take place, clot dissolves
- as enzyme plasmin digests fibrin
- specific enzymes are needed
Inactive plasmin present in blood in form of plasminogen, converted to plasmin as a result of tPA (tissue Plasminogen Activator) activity
- plasminogen is incorporated into clot as it forms
65
What is serum?
Plasma with clotting proteins removed
66
Blood typing: what antigen and antibodies doe each type have?
Type A: Surface antigen A, anti-B antibodies
Type B: Surface antigen B, anti-A antibodies
Type AB: Surface antigens A and B, no antibodies
Type O: No surface antigens, anti-A, anti-B antibodies
67
What happens when matching antigens and antibodies are allowed to mix?
Agglutination / clumping
68
What are antigens?
Plasma membrane of our RBCs can contain a number of different proteins, sometimes referred to as antigens. A person's antigens are genetically determined
An antigen is any substance that the immune system recognizes as foreign or harmful, prompting an immune response. These can be molecules on the surface of pathogens like bacteria, viruses, or even allergens.
69
What are antibodies?
An antibody is a protein produced by the immune system in response to an antigen. It binds to the antigen to neutralize it or mark it for destruction by other immune cells.
70
What do you need to do before transfusing blood to a patient?
1. Blood typing (determine ABO)
2. Crossmatch testing (mix donor and recipient blood in well)
71
What happens if you do not transfuse the correct type of blood?
Surface antigen (ex. A) + Opposing antibodies (anti-A antibodies in antigen B blood) -> agglutination (clumping) and hemolysis (destruction of RBCs)
72
How are blood types determined?
Both parents contribute in determining their child's blood type
there are 2 alleles (antigen A and antigen B) that determine ABO blood type
there are 2 alleles (on a separate gene loci) that determine whether Rh antigen is produced
73
What is Rh?
An additional factor that can be present (+) or absent (-) on the RBC
antibodies to Rh are only produced after exposure (ex. when a Rh- mother has carried a Rh+ baby)
74
What is Rh factor?
The risk of fetal Rh disease resulting from Rh- mothers carrying Rh+ babies
- the most common (86%) sensitizing event is childbirth, but fetal blood may pass into the maternal circulation earlier than pregnancy
- it is a part of modern antenatal care to give all Rh(-) pregnant women an anti-RhD IgG immunoglobulin injection at 28 weeks gestation, with a booster at 34 weeks. also a booster will be given within 72 hours after any potential sensitizing events that occur early in pregnancy
75
How much blood does it take to save a life?
1 unit of blood = 200 mL RBCs + 100 mL additive solution
Cancer treatment: up to 8 units per week
Coronary artery bypass: 1-5 units
Auto accident / gunshot wounds: up to 50 units
Liver transplant: up to 100 units
Other organ transplants: up to 10 units
Brain surgery: 4-10 units
Fractured hip/joint replacement: 2 to 5 units
76
What occurs during pregnancy of a Rh- mother with a Rh+ baby?
1. First pregnancy
2. Hemorrhaging at delivery
3. Maternal antibody production (anti-Rh)
4. Second pregnancy: maternal blood now contains Anti-Rh
