chapter 17: Blood
Which of the following statements about blood is TRUE?
- Blood helps stabilize body temperature. - Blood is used to transport respiratory gases. - Blood defends against toxins and pathogens.
Which of the following IS a function of the blood?
- Defend against pathogens - Regulation of pH and ion composition of interstitial fluids - Transportation of gases, nutrients, hormones, and wastes
Which of the following IS a benefit of the unusual shape of the red blood cell?
- Red blood cells can stack up on each other. - They are flexible. - Increased surface-to-volume ratio
structure and function of platelets
- appearance in a stained blood smear: platelets are flattened discs that appear round when viewed from above and appear spindle-shaped in section or an a blood smear. - abundance (average number per μL): 350,000 (range: 150,000 - 500,000) - function: platelets clump together and stick to damaged vessel walls, and they release chemicals that stimulate blood clotting. - remarks: platelets are continuously replaced. each platelet circulates for 9 to 12 days before being removed by phagocytes, mainly in the spleen.
RBC test and related terminology
- hematocrit (Hct) Determines: percentage of formed elements in whole blood normal = 37 to 54% Elevated: polycythemia Depressed: anemia - hemoglobin concentration (Hb, Hgb) Determines: concentration of hemoglobin in blood. Normal = 12-18g/dL Elevated: polycythemia Depressed: anemia - mean corpuscular hemoglobin concentration (MCH) Determines: average weight of Hb in one RBC. Normal = 27-34μg/RBC (normochromic) Elevated: hyperchromic Depressed: hypochromic - mean corpuscular volume (MCV) Determines: average volume of 1 RBC. Normal = 82-101μm³/cell (normocytic) Elevated: macrocytic Depressed: microcytic - RBC count Determines: number of RBCs per μL of whole blood. Normal = 4.2-6.3 million cells/μL Elevated: erythrocytosis/ polycythemia Depressed: anemia - reticulocyte count (Retic.) Determines: percentage of circulating reticulocytes. Normal = 0.8% Elevated: reticulocytosis Depressed: diminished erythropoiesis
Water (92%)
- platelets: smooth, membrane-bound cell fragments that contain enzymes and other substances important for clotting - white blood cells (WBC) (<0.1%): or leukocytes, play a role in the body's defense mechanisms. there are five classes of leukocytes, each with slightly different functions: · neutrophils · eosinophils · basophils · lymphocytes · monocytes - red blood cells (RBCs) (99.9%): or erythrocytes, are the most abundant blood cells. these specialized cells are essential for the transport of oxygen in the blood.
In which phase of hemostasis is fibrin deposited, creating a solid blood clot?
Coagulation phase
Which of the following is a notable feature of leukemia?
Excessive numbers of white blood cells
In the process of hemostasis, what triggers the Extrinsic Pathway of the coagulation phase?
Factor III (Tissue Factor or TF)
Red blood cells have a limited lifespan and then are phagocytized by macrophages in the liver, spleen and red bone marrow. What happens to the iron in the heme group of RBCs?
The iron will be either stored in the liver or transported back to the red bone marrow to be incorporated into new hemoglobin.
agranular leukocytes
contains secretory vesicles and lysosomes smaller than those in granulocytes. however, few, if any, of those cytoplasmic granules absorb histological stain. monocytes lymphocytes
hemopoiesis (hematopoiesis)
develop in red bone marrow
events occurring in the red bone marrow
developing rbc's absorb amino acids and iron from the bloodstream and synthesize new HB molecules. cells destined to become RBCs first differentiate into proerythroblasts. Proerythroblasts then differentiate into various stages of cells called erythroblast, which actively synthesize hemoglobin. every through glass are named according to Total size, amount of hemoglobin present in size and appearance of the nucleus. after roughly four days of differentiation, the erythroblast, now called a normoblast, sheds its nucleus and becomes a reticulocyte, which contains 80% of the HB of a mature RBC. after two days in the bone marrow reticulocytes enter the bloodstream reticulocytes account for about 0.8% of the circulating rbc's. after 24 hours in circulation, the reticulocytes complete their maturation and resemble other mature RBCs in the bloodstream, the rupture of rbc's is called hemolysis. day 1: cells destined to be RBCs first differentiate into proerythroblasts day2: basophilic erythroblast day 3: polychromatophillic erythroblast day 4: normoblast
blood vessels
distribute blood around the body
blood
distributes oxygen, carbon dioxide, and blood cells; delivers nutrients and hormones; transports waste products; and assist in temperature regulation and defense against disease.
heme
each heme unit holds an iron ion in such a way that the iron can interact with an oxygen molecule, forming oxyhemoglobin, HbO2. blood containing rbc's filled with oxyhemoglobin is bright red. The iron oxygen interaction is very weak, and the two can easily dissociate without damaging the heme unit or the oxygen molecule. The binding of an oxygen molecule to the iron in a heme unit is therefore completely reversible the hemoglobin molecule whose iron is not bound to oxygen is called deoxyhemoglobin, or reduced hemoglobin. blood containing rbc's filled with deoxyhemoglobin is dark red - almost burgundy
how much oxygen can a red blood cell carry?
each red blood cell contains about 280 million HB molecules. because one HB molecule contains four heme units, each RBC can potentially carry more than a billion molecules of oxygen at a time. roughly 98.5% of the oxygen carried by blood travels through the bloodstream bound to HB molecules inside rbc's. The rest is dissolved in the plasma.
megakaryocytes
enormous cells (up to 160 μm in diameter) with large nuclei. during their development and growth, megakaryocytes manufacturer structural proteins, enzymes, and membranes before shedding cytoplasm and small, membrane-enclosed packets. these packets are the platelets that enter the bloodstream.
identify the components of the cardiovascular system
heart, blood, blood vessels
Protein synthesis in a mature RBC occurs primarily ___
nowhere; mature red blood cells cannot synthesize proteins
Antigens
substances that can trigger a protected defense mechanism called an immune response. Most antigens are proteins, but some other types of organic molecules are antigens as well. The plasma membranes of your cells contain surface antigens, substances your immune system recognizes as normal, or self. in other words, your immune system ignores these substances rather than attacking them as foreign.
Why is RhoGAM administered to Rh- mothers?
to prevent isoimmunization from potential exposure to Rh-positive fetal blood during pregnancy.
Which of the following IS a surface antigen that is used in determining blood type?
- Rh - A - B
properties of whole blood
- what temperature is about 100.4 degrees Fahrenheit, slightly above normal body temperature. - blood is 5 times as viscous as water - that is 5 times as resistant to flow. blood's high viscosity results from interactions among dissolved proteins, formed elements, and water molecules in the plasma. - blood is slightly alkaline, with a pH between 7.35 and 7.45 (average: 7.4)
formed elements
45% (range 37-54%) red blood cells white blood cells platelets formed elements are blood cells and cell fragments suspended in plasma. They make up to 45% of the volume of whole blood.
How much blood does an adult male normally have?
5-6 liters
What is jaundice?
A yellowing of the skin and eyes
If a person has type A blood, Rh surface antigens on the blood cells, and anti-B antibodies in the plasma, what is that person's blood type?
A-positive
Which of the following is a compound that stimulates platelet aggregation?
ADP
Why is there a difference in the hematocrit between males and females?
Androgens stimulate red blood cell production and estrogens do not.
What of the following types of blood would cause a cross-reaction when given to a person with type A-positive blood?
B-positive
Which of the following statements about blood is FALSE?
Blood is slightly acidic, with a pH of 6.5.
What is the primary site of erythropoiesis in an adult?
Bone marrow
Which of the following is NOT a surface antigen that is used in determining blood type?
C
Which of the following affect almost every aspect of the clotting process?
Calcium ions and vitamin K
A decreased number of megakaryocytes would interfere with what process?
Clot formation
Which of the following are not components of plasma?
Elastic fibers
In addition to water and proteins, what else make up plasma?
Electrolytes, nutrients, and organic wastes
Leukocytes or white blood cells fight infection. They have the ability to leave the bloodstream and enter a damaged or infected area. What is the name of this process of leaving the bloodstream?
Emigration or diapedesis
Which of the following is a locally produced hormone causing smooth muscle contraction during the vascular phase?
Endothelin
Which of the following types of white blood cells are involved in fighting off parasitic infections, such as flukes and roundworms?
Eosinophils
Which component makes up the largest proportion of the formed elements?
Erythrocytes
What is the specific term for the production of red blood cells?
Erythropoiesis
Which of the plasma proteins functions in blood clotting?
Fibrinogen
Which category of plasma proteins includes antibodies?
Globulins
What type of molecules are the antigens found on our blood cells?
Glycoproteins and glycolipids
Which of the following is NOT a benefit of the unusual shape of the red blood cell?
Greater hemoglobin carrying capacity
Type O
Has RBCs without both A and B surface antigens. If you have type O blood, your plasma contains both anti-A and anti-B antibodies type O is often called a universal donor.
A patient developed an obstruction in his renal arteries that restricted blood flow to his kidneys. What change would occur to the formed elements?
Hematocrit would increase.
Which part of hemoglobin binds oxygen?
Heme
Which plasma protein would you expect to be elevated if you were suffering from strep throat?
Immunoglobulins
Placing blood in a test tube initiates which pathway in the clotting process?
Intrinsic pathway
Nonspecific defenses do not discriminate between one type of threat or another. The specific immune response will provide a counterattack against specific types of invading pathogens. What cell type is responsible for specific defense?
Lymphocytes
Which type of white blood cell circulates in the blood for about 24 hours before entering the tissues and differentiating into a macrophage?
Monocyte
What type of white blood cell would you find in the greatest numbers in an infected cut?
Neutrophil
Which group of white blood cells are classified as granulocytes?
Neutrophils, eosinophils, and basophils
If agglutinogen B meets with agglutinin anti-A, what is the result?
No agglutination occurs.
In which pregnancy are an Rh-positive mom and an Rh-positive child at risk of developing erythroblastosis fetalis?
No pregnancy
what is the most common blood type in the United States?
O+
which blood types can be safely transfused into a person with type O- blood?
O-
Which of the following is/are not (a) formed element(s)?
Plasma
What is the term for the characteristic of white blood cells in which they are attracted to a specific chemical stimulus?
Positive chemotaxis
Proportionately, what is the largest component of the plasma, other than water?
Proteins
Type AB
RBCs with both A and B surface antigens. If you have Type AB blood, your plasma has neither anti-A or anti-B antibodies. type AB is often called universal recipients or acceptors.
Rouleaux
Stacks of RBCs. form in dissociate repeatedly without affecting the cells involved.
Even if blood is carefully collected into a tube that has not been treated with an anticoagulant, it will clot. Which part of hemostasis is triggered by the activation of clotting factor XII?
The intrinsic pathway
What is hematocrit?
The percentage of formed elements in whole blood.
Which of the following IS a function of platelets?
They patch damaged vessels. They initiate blood clotting. They reduce the size of a break in a vessel.
Which of the following is NOT a function of platelets?
They release chemicals to destroy bacteria.
How do basophils respond to an injury?
They release histamine and heparin.
Which two enzymes are needed to convert plasminogen to plasmin?
Thrombin and tissue plasminogen activator (t-PA)
The primary function of a mature red blood cell is which of the following?
Transport of respiratory gases
What type of blood is considered to be the "universal donor"?
Type O negative
In which phase of hemostasis does local contraction of an injured blood vessel occur?
Vascular phase
What are the "patrol agents" in the blood that defend the body against toxins and pathogens?
White blood cells and antibodies
WBC differential count (17.9)
a variety of conditions, including infections, inflammation, and allergic reactions, cuz characteristic changes in the populations of circulating wbc's. examining a stained blood smear can provide a window on such changes. A WBC differential count identifies the types in numbers of white blood cells in a sample of blood. The values reported indicate the number, as a percentage, of each type of cell in a sample of 100 wbc's.
anucleate
because mature rbc's lack nuclei, a condition called anucleate, and also lack ribosomes, they cannot divide or synthesize structural proteins are enzymes. as a result, rbc's cannot repair themselves and their life span is normally less than 120 days. in effect, a developing RBC loses any organelle not directly associated with this primary function; the transport of respiratory gases.
What are the major components of the cardiovascular system?
blood, heart, and blood vessels
Arteries
carry blood away from the heart to the capillaries
Agglutinogens are contained on the ___, whereas the agglutinins are found in the ___.
cell membrane of the RBC; plasma
Signs of iron-deficiency anemia include ___
decrease in hematocrit, hemoglobin content, and O2-carrying capacity
Reticulocytes are nucleated immature cells that develop into mature ___
erythrocytes
Thrombin is required to convert ___
fibrinogen to fibrin
which specific plasma proteins would you expect to be elevated during an infection?
immunoglobulins (antibodies)
Erythropoiesis
in adults red blood cell formation occurs only in red bone marrow or myeloid tissue. The tissue is located in portions of the vertebrae, sternum, ribs, School, scapulae, pelvis and proximal and Bones. other marrow area is contain a fatty tissue known as yellow bone marrow. under extreme stimulation, such a such severe and sustained blood loss, areas of yellow marrow can convert to red marrow, increasing the rate of RBC formation.
events occurring in the large intestine
in the large intestine, bacteria convert bilirubin into urobilins and stercobilins. feces are yellow-brown or brown because the presence of urobilins and stercobilins and varying proportions.
Where are most plasma proteins produced?
liver
Erythropoietin appears in the plasma when peripheral tissues, especially the kidneys, are exposed to ___
low oxygen concentration
Myeloid stem cells develop into ___
megakaryocytes
Capillaries
permit diffusion between blood and interstitial fluids
Platelets promote vessel repair by releasing ___
platelet derived growth factor
In order to produce a massive amount of fibrin molecules, thrombin needs to be present. To ensure abundance of thrombin production, thrombin stimulates its own production by stimulating the formation of tissue factor and PF-3, which activates further platelet aggregation. This pattern of stimulation is known as a ___
positive feedback loop
heart
propels blood and maintains blood pressure
The formed elements of the blood consist of ___
red and white blood cells and platelets
Veins
return blood from capillaries to the heart
myeloid stem cells
stem cells in red bone marrow that divide to give rise to all types of formed elements other than lymphocytes.
Which of the following is NOT a good reason why venipuncture is a common technique for obtaining a blood sample?
Blood does not clot as easily coming from veins as it does from arteries.
first pregnancy of an RH - mother with an Rh+ infant
In it's most common form. hemolytic disease of the newborn develops after an rh- woman carried an RH+ fetus. unlike anti a and anti-b antibodies, anti-rh antibodies are able to cross the placenta and enter the fetal bloodstream. 1. during a first pregnancy, problem sell them develop because very few fatal cells enter the maternal bloodstream and fuss the mother's immune system is not stimulated to produce anti-Rh antibodies. 2. exposure to fetal red blood cell antigens generally occurs during delivery, when bleeding takes place at the placenta and uterus. such mixing of fetal and maternal blood can stimulate the mother's immune system to produce anti-rh antibodies, leading to sensitization. 3. about 20% of Rh- mothers who carried RH+ children become sensitized within 6 months of delivery. because the anti-rh antibodies are not produced in significant amounts until after delivery, a woman's first infant is not affected.
How is it that liver disorders can alter the composition and the functional properties of blood?
The liver is the primary source of plasma proteins.
events occurring in the liver
bilirubin is Destined for excretion in bile. if the bile ducts are blocked or the liver cannot process bilirubin, circulating levels of the compound increase rapidly bilirubin then diffuses into peripheral tissues, giving them a yellow color that is apparent in the skin and the sclera of the eyes. The yellowish discoloration of the skin and eyes is called jaundice.
in what way would a liver disease affect the level of bilirubin in the blood?
bilirubin would accumulate in the blood producing jaundice.
During RBC recycling, each heme unit is stripped of its iron and converted to ___
biliverdin
Plasma
blood consists of plasma. A liquid matrix, and formed elements blood (cells and cell fragments). The cardiovascular system of an adult male contains 5 to 6 liters of blood; that of an adult female contains 4 to 5 liters. 55% (Range 46-63%) - plasma proteins - water - other solutes plasma forms 55% of the volume of whole blood. in many respects the composition of plasma resembles that of interstitial fluid. The similarity exist because of water, ions, and small solutes are continuously exchange between plasma and interstitial fluids across the walls of capillaries. the differences between plasma and interstitial fluid involve: 1. the levels of respiratory gases (oxygen and carbon dioxide) do to the respiratory activities of tissue cells. 2. the concentrations and types of dissolved proteins (because plasma proteins cannot cross capillary walls.)
What kind of tissue is blood?
fluid connective tissue
Hemocytoblast
form from hematopoietic stem cells (HSCs). for RBCs to be produced, hemocytoblasts in the red bone marrow must divide, producing two types of cells: lymphoid stem cells and myeloid stem cells. lymphoid stem cells divide to produce white blood cells called lymphocytes. myeloid stem cells divide to produce RBCs and several classes of white blood cells.
Megakaryocytes are specialized cells of the bone marrow that are responsible for ___
formation of platelets
hemolytic disease of the newborn (HDN)
genes controlling the presence or absence of any surface antigen in the plasma membrane of a red blood cell are provided by both parents, so a child can have a blood type different from that of either parent. during pregnancy when fetal and maternal vascular systems are closely intertwined, the mother's antibodies against RBC surface antigens may cross the placenta, attacking and destroying fetal rbc's. The resulting condition, called hemolytic disease of the newborn, has many forms, some quite dangerous and others so mild as to remain undetected.
Type B
has rbc's with surface antigen B only. if you have type B blood your plasma contains anti-a antibodies.
granular leukocytes
have abundant cytoplasmic granules that absorb histological stains, such as Wright stain or Giesma stain. neutrophils eosinophils basophils
white blood cells (leukocytes)
have nuclei and other organelles and lack hemoglobin. a phrase to help you remember the five types of wbc's is "never let monkeys eat bananas" N - neutrophils L - lymphocytes M - monocytes E - eosinophils B - basophils
colony stimulating factors
hormones released by activated lymphocytes and other cells during an immune response to stimuli blood cell formation.
Jessica has just moved from Orlando, Florida, to Denver, Colorado. What condition is she now experiencing that is stimulating the production of erythropoietin and, consequently, more red blood cells?
hypoxia caused by an increase in her elevation above sea level
second pregnancy of an Rh- mother with an Rh+ infant
if a future pregnancy involves an RH positive fetus, maternal anti-rh antibodies produced after the first delivery cross the placenta and enter the fetal bloodstream. these antibodies destroy fetal rbc's, producing a dangerous anemia. The fetal demand for red blood cells increases, and they leave the bone marrow and enter the bloodstream before completing their development. because these immature rbc's are erythroblasts, HDN is also known as erythroblastosis fetalis. without treatment, a fetus with erythoblastostosis fetalis me die before delivery or shortly thereafter. and you born with severe hdn is anemic, and the high concentration of circulating bilirubin produces jaundice. because the maternal antibodies remain active in the newborn for 1 to 2 months after delivery, the infant's entire blood volume may require replacement to remove the maternal anti-rh antibodies, as well as the damaged rbc's. fortunately the mother's anti-rh antibodies production can be prevented if anti-rh antibodies (available under the name RhoGAM) are administered to the mother and weeks 26 to 28 of pregnancy and during and after delivery. these antibodies destroy any fetal rbc's that cross the placenta before they can stimulate a maternal immune response. because maternal sensitization does not occur, no anti-rh antibodies are produced.
degenerative blood disorders
in disseminated intravascular coagulation (DIC), BACTERIAL TOXINS ACTIVATE SEVERAL STEPS IN THE QUAY GALATIAN PROCESS THAT CONVERTS FIBRINOGEN TO FIBRIN WITHIN THE CIRCULATING BLOOD. although much of the fibrin is removed by phagocytes or is dissolved by plasmin, small clots May block small vessels and damaged nearby tissues. If the liver cannot produce enough circulating fibrinogen to keep Pace with the rate at which fibrinogen is being removed, clotting abilities decrease, and uncontrolled bleeding may occur.
cardiovascular system
includes fluid (blood) , a series of conducting tubes (the blood vessels) that distribute the fluid throughout the body, and a pump (the heart rate) that keeps the fluid in motion
nutritional blood disorders
iron deficiency anemia, normal hemoglobin synthesis cannot occur because either iron reserves or the dietary intake of iron is inadequate. because developing rbc's cannot synthesize functional hemoglobin, they are unusually small (microcytic). women are especially dependent on a normal dietary supply of iron because they're iron reserves are about 1/2 that of a typical man. a deficiency in vitamin B12 prevents normal stem cell divisions in the bone marrow, which can result in pernicious anemia. fewer red blood cells are produced, and those that are produced are abnormally large (macrocytic) and may develop bizarre shapes. pernicious anemia can also result from a lack of intrinsic factor, a mucoprotein secreted by the stomach that is necessary for adequate vitamin B12 absorption. calcium ions and vitamin k affect almost every aspect of the clotting process. all three pathway (intrinsic, extrinsic, and common) require calcium, so any disorder that lowers blood calcium levels can impair blood clotting. additionally, the liver requires adequate amounts of vitamin k for synthesizing for of the clotting factors, including prothrombin.
Vascular phase of hemostasis
last for roughly 30 minutes after the injury occurs. It is dominated by the response of the endothelial cells and the contraction, or a vascular spasm, of smooth muscle of the vessel walls. events of the vascular phase: - the endothelial cells contract and expose the underlying basement membrane to the bloodstream - the endothelial cells begin releasing chemical factors and local hormones. endothelial cells also release endothelins, peptide hormones that: (1) stimulate smooth muscle contraction and promote vascular spasms (2) stimulate the division of endothelial cells, smooth muscle cells, and fibroblasts to accelerate the repair process. - the endothelial plasma membranes become sticky. A tear in the wall of a small artery or vein may be partially sealed off by the attachment of endothelial cells on either side of the break. in small capillaries, endothelial cells on opposite sides of the vessel may stick together and prevent blood flow along the damaged vessel. The stickiness also AIDS the attachment of platelets as the platelet phase gets underway.
blood cell cancers
leukemia's are Cancers of blood-forming tissues. The cancerous cells of leukemia do not form a compact tumor, but instead are spread throughout the body from their origin in red bone marrow. both of the two types of leukemia - myeloid and lymphoid - are characterized by elevated levels of circulating WBC. myeloid leukemia is characterized by the presence of abnormal granulocytes (neutrophils, eosinophils, and basophils) or other cells of the bone marrow. lymphoid leukemia involves lymphocytes and there stem cells. The first symptoms appear when immature an abnormal white blood cells appear in the bloodstream. untreated leukemia is invariably fatal.
events occurring in macrophages
macrophages monitor the condition of circulating rbc's, and golfing them before they hemolyzed (rupture) , and removing HB molecules and cell fragments from the rbc's that hemolyze in the bloodstream. iron extracted from heme molecules may be stored in the phagocyte or release into the bloodstream, where it binds to transferrin, a plasma protein. the globular proteins are disassembled into their component amino acids, which can be released into the bloodstream for used by other cells. each heme unit is stripped of its iron and converted into biliverdin, inorganic compound with a green color. biliverdin is then converted into bilirubin and released into the bloodstream. bilirubin binds to the albumin and is transported to the liver.
Platelets are formed from large cells called ___
megakaryocytes
Circulating mature RBCs lack ___
mitochondria, ribosomes, nuclei
what are two types of leukemia?
myeloid and lymphoid
other solutes 1%
other solutes are generally present in plasma in concentration similar to interstitial fluid. however, arterial blood and venous blood can contain different concentrations of nutrients and wastes. - electrolytes: normal extracellular ion composition is essential for vital cellular activities. The major plasma electrolytes are Na+, K+, Ca²+, Mg2+, Cl-, HCO3-, HPO4-, SO4²- - organic nutrients: organic nutrients are used for ATP production, gross and cell maintenance. this category includes lipids (fatty acids, cholesterol, and glycerides) , carbohydrates (primarily glucose) , and amino acids. - organic wastes: Weezer carry two sites for breakdown or execution. examples of organic wastes include urea, uric acid, creatinine, bilirubin, and ammonium ions.
Where are red blood cells produced in an adult?
red bone marrow
Erythropoietin (EPO)
released into the plasma when peripheral tissues, especially the kidneys, are exposed to low oxygen concentrations. The state of low tissue oxygen levels is called hypoxia. erythropoietin is released 1) during anemia 2) when blood flow to the kidneys 3) when the oxygen content of air in the lungs decreases due to disease or high altitude 4) when the respiratory surfaces of the lungs are damaged. once in the bloodstream, EPO is Kerry two areas of red bone marrow, where it stimulates stem cells and developing rbc's.
lymphoid stem cells
responsible for the production of lymphocytes, which are cells that function in the immune response. these stem cells originate in the red bone marrow. some remain there, whereas others migrate to lymphoid tissues, including the thymus, spleen, and lymph nodes. lymphocytes are produced in these organs as well as in the red bone marrow.
congenital blood disorders
sickle cell disease (SCD) IS A GROUP OF INHERITED RBC DISORDERS. ALL ARE DUE TO MUTATIONS IN THE CHAINS OF HB MOLECULE. AFFECTED RBC'S TAKE ON A SICKLE SHAPE WHEN THEY RELEASE FOUND OXYGEN, MAKING THE RBC'S FRAGILE AND EASILY DAMAGED. MOREOVER, A SICKLED RBC CAN BECOME STUCK IN A CAPILLARY BLOCKING THE FLOW OF BLOOD AND OXYGEN TO NEARBY TISSUES. to develop the most severe SCD, sickle cell anemia, a person must have two copies of the sickling Gene - one from each parent. If only one sickling Gene is present, the person has the sickling trait. in such cases, most of the hemoglobin is of the normal form, and rbc's function normally. however having a sickling trait gives the person some resistance to malaria, a deadly mosquito-borne parasite disease. infection of rbc's by the parasites and deuces sickling, a sickled cell containing the parasites are involved and destroyed by macrophages. thalassemias are forms of SCD. they are also caused by an inability to produce adequate amounts of normal protein subunits of hemoglobin. The severity of different types of thelassemias depends on which and how many protein subunits are abnormal. hemophilia is an inherited bleeding disorder. about one person in 10,000 are hemophiliac, and of those, 80 to 90% are males. in most cases hemophilia is caused by reduced production of a single clotting factor. the severity of hemophilia varies, depending on how little clotting factor is produced. in severe cases, extensive bleeding occurs with relatively minor contact, and bleeding occurs at joints and around muscles..
Agglutinogens
surface antigens on rbc's are also known as agglutinogens, because if antigens of one blood type are exposed to the corresponding antibodies also known as agglutinins, from another type, the rbc's will come together in a process called agglutination. The cells may also undergo hemolysis. such a cross reaction is very dangerous because clumps and fragments of rbc's can plug small blood vessels in the kidneys, lungs, heart, or brain, damaging or destroying affected tissues. accidental cross reactions may occur if a person being treated for severe blood loss is accidentally given a transfusion of the wrong blood type.
Rh blood group
the RH blood group is based on the presence or absence of the RH surface antigen. The term RH positive (Rh+) indicates the presence of the RH surface antigen. It is referred to as "Rh" because this antigen was first discovered in rhesus monkeys before it was found in humans. The absence of this antigen is indicated as Rh negative (Rh-) . when the complete blood type is recorded, RH is usually omitted and blood type is reported as O negative (O-), A positive (A+), and so on..
blood type
your blood type is determined by specific surface antigens in RBC plasma membranes. The surface antigens are integral membrane and glycoproteins whose characteristics are genetically determined. your immune system ignores the surface antigens on your own rbc's. however your plasma may contain antibodies that will attack the antigens on foreign rbc's. Although red blood cells have at least fifty kinds of surface antigens, three surface antigens are of particular importance: A, B, and Rh (also called D). the ABO blood group is based on the presence or absence of the A and B surface antigens. according to this group there are four blood types.
Type A
type A blood has rbc's with surface antigen A only. if you have type A blood, your plasma contains anti-b antibodies, which will attack type B surface antigens
Which blood type can safely be transfused into a person with type O blood?
type O
functions of blood
- transport dissolved gases, nutrients, hormones and metabolic wastes: circulating blood contains red blood cells that carry oxygen from the lungs to peripheral tissues and carry carbon dioxide from those tissues to the lungs. blood distributes nutrients absorbed by the digestive tract or released from storage in adipose tissue or in the liver. It carries hormones from the endocrine glands toward the target cells. It also absorbs cellular waste and carries them to the kidneys for excretion. - regulate the pH and ion composition of interstitial fluids: diffusion between interstitial fluids and blood eliminates local deficiencies or excess of ions such as calcium or potassium. blood also absorbs and neutralizes metabolic acids generated by active tissues. - restrict fluid losses at injury sites: but contains enzymes and other substances that respond to breaks in vessel Walls by initiating the clotting process. A blood clot acts as a temporary patch that prevents further blood loss. - defend against toxins and pathogens: blood transports white blood cells, specialized cells that migrated into peripheral tissues to fight infections or remove debris. blood also transports antibodies, proteins that specifically attacked invading organisms or foreign substances. - stabilize body temperature: what absorbs the heat generated by active skeletal muscles and redistribute it to other tissues. If body temperature is already high, that he will be lost across the surface of the skin. If blood temperature is too low, the warm blood is directed to the brain and two other temperature-sensitive organs.
Sherry properties of WBCs
- wbc's circulate for only a short portion of your lifespan, using the bloodstream primarily to travel between organs and too rapidly reach areas of infection or injury. WBC spend most of their time migrating through loose and dense connective tissues throughout the body. - all wbc's can migrate out of the bloodstream. when circulating wbc's in the bloodstream become activated, they contact and adhere to the vessel walls and squeeze between adjacent endothelial cells to enter the surrounding tissue. this process is called and the emigration, or diapedesis. - all wbc's are attracted to specific chemical stimuli. this characteristic, called positive chemotaxis, guides wbc's to invading pathogens, damaged tissues, and other active wbc's. - neutrophils, eosinophils, and monocytes are capable of phagocytosis. they can engulf pathogens, soda breeze, or other materials. macrophages are monocytes that move from the bloodstream into peripheral tissues.
red blood cell count
a standard red blood cell count reports the number of rbc's per microliter of whole blood. in adult males, 1 microliter, or 1 cubic millimeter, of whole blood contains 4.5 to 6.3 million rbc's; in adult females, one microliter contains 4.2 to 5.5 million. A single drop of whole blood contains approximately 260 million rbc's, and the blood of an average adult has 25 trillion rbc's. rbc's first account for roughly one-third of all cells in the human body. each RBC is a biconcave disc with a thin central region and a thicker outer margin. the biconcave shape and flexible plasma membrane of an RBC are important for the three reasons detailed: - large surface area to volume ratio: each RBC carries oxygen bound to hemoglobin, an intracellular protein, and that oxygen must be absorbed or released quickly as the RBC passes through the capillaries. The greater the surface area per unit volume, the faster the extinct exchange of materials between the rbc's interior and the surrounding plasma. The total surface area of all the rbc's in the blood of a typical adult is about 3800 square meters, roughly two thousand times the total surface area of the body. - rbc's can form stacks: like dinner plates, rbc's can form stacks that he's the flow through narrow blood vessels. an entire stack can pass along a blood vessel only slightly larger than the diameter of a single RBC, whereas individual cells would bump the walls, bang together, and form logjams that could restrict or prevent blood flow. - flexibility: the cytoplasmic surface of an RBC plasma membrane is a meshwork a flexible proteins. as a result, rbc's can bend and flex when entering small capillaries as narrow as 4μm.
Red Blood Cells (RBC)
about 1% of the circulating rbc's are replaced each day, and in the process of approximately 3 million new rbc's enter the bloodstream each second. such a rapid rate of replacement is necessary because typical RBC has a relatively short lifespan. after it travels about 700 miles in a 120 days, either it's plasma membrane ruptures, or it is engulfed by macrophages in the spleen, liver, or bone marrow. The continual elimination of rbc's usually goes unnoticed as long as new ones enter the bloodstream at a comparable rate.
Hemoglobin (Hgb, Hb)
account for more than 95% of an RBC intracellular proteins. The hemoglobin content of whole blood is reported in grams of Hb per deciliter (100mL) of whole blood (g/dL). normal ranges are 14-18 g/dL in males and 12-16 g/dL in females. hemoglobin has a complex quaternary protein structure. each Hb molecule has to alpha chains and 2 beta chains of polypeptides. each gene is a globular protein subunit that resembles the myoglobin in skeletal and cardiac muscles. like myoglobin, each Hb chain contains a single molecule of heme, a non protein pigment complex.
Clot destruction involves a process that begins with ___
activation of the proenzyme plasminogen, which initiates the production of plasmin
whole blood
after blood is removed for analysis of. used to indicate that the blood composition has not been altered. The components of whole blood can however be separated or fractionated if only one component is of interest.
The number of eosinophils increases dramatically during ___
an allergic reaction or a parasitic infection
which condition would a patient have if she had a depressed hematocrit level?
anemia
plasma proteins
are in solution rather than forming insoluble fibers like those in other connective tissues, such as loose connective tissue or cartilage. on average each 100 ml of plasma contains 7.6 grams of protein, almost five times the concentration of interstitial fluid. the large size and globular shapes of most blood proteins usually prevent them from leaving the bloodstream. The liver synthesizes and releases more than 90% of all plasma proteins. - albumins: make up 60% of the plasma proteins. as the most abundant plasma proteins, they are major contributors to the osmotic pressure of plasma. - globulins: make up approximately 35% of the protein in plasma. important plasma globulins include antibodies and transport globulins. antibodies, also called immunoglobulins, attack foreign proteins and pathogens. transport globulins by and small ions, hormones, lipids, and other compounds. - fibrinogen: functions including a normally makes up about 4% of plasma proteins. under certain conditions, fibrinogen molecules interact to form large, insoluble strands of fibrin that form a basic framework for a blood clot. the plasma also contains active and inactive enzymes and hormones whose concentrations vary widely.
blood infections
blood is normally free of microorganisms, but they can enter the blood through a wound or infection. bacteremia is a condition in which bacteria circulate in blood but do not multiply there. Viremia is a similar condition associated with viruses. sepsis is a widespread pathogenic infection of body tissues. sepsis of the blood, or septicemia (formerly known as blood poisoning) results if pathogens are present and multiplying in the blood and spreading throughout the body. malaria is a parasitic disease caused by several species of the protozoan plasmodium. It is one of the most severe diseases in tropical countries, killing 1.5 to 3 million people per year, of which up to have our children under the age of five. Malaria is transmitted from person to person by a mosquito. The parasite initially infects liver cells, then enlarges the fragments into smaller forms that affect red blood cells. periodically, at intervals of two to three days, all of the infected rbc's rupture simultaneously and release more parasites that infect and additional rbc's. The release and an reinfection of rbc's corresponds to the cycles of fever and chills that characterize malaria. Dead rbc's can blocked blood vessels leading to vital organs, such as the kidney and brain resulting in tissue death.
hematology
the city of blood, blood for me tissues, and blood disorders. is important as a branch of science because much can be learned about a person's health by evaluating blood. blood provides a readily accessible medium for diagnosing and treating disease. blood test can detect disorder such as anemia, infection and clotting disorders. since blood courses through nearly every tissue of the body dyscrasias, popular disorders can systemic effects. blood tests are used for many reasons. some are simple such as determining blood type; others are done to evaluate the types and numbers of rbc's, wbc's, and platelets. when tests commonly performed is a complete blood count (CBC). a CBC determines the RBC count, WBC count, erythrocyte indices such as hemoglobin content, hematocrit, and the platelet count in one cubic millimeter of blood. A WBC differential count identifies the types and numbers for each white blood cell. blood clotting test and bleeding time give information on blood coagulation. abnormal values may indicate underlying medical conditions. several come and test focus on rbc's and assess the number, size, shape, and maturity of circulating rbc's, indicating the erythropoietic activities underway. The test can also be useful in detecting problems such as internal bleeding, that may not produce obvious signs or symptoms..
coagulation phase in homeostasis
the graduation phase of homeostasis does not start until 30 seconds or more after vessel damage. and, or blood clotting, involves intertwine Cascades call the extrinsic, intrinsic, in common pathways. these pathways lead to the conversion of circulating fibrinogen (a soluble protein) into fibrin (and insoluble protein). as the fiber Network grows, blood cells and additional platelets become trapped, forming a blood clot that seals off the damaged portion of the vessel. procoagulant (clotting factors) in the plasma play a key role in this phase. essential clotting factors include calcium and 11 different proteins (identified by Roman numerals) . many clotting factors are pro enzymes (in active enzymes) which, when converted to active enzymes, direct essential reactions in the clotting response. The activation of one proenzyme commonly creates a Cascade, or chain reaction of successive events. Extrinsic Pathway: the extrinsic pathway begins with the release of tissue factor (factor III) buy damaged endothelial cells or peripheral tissues. The greater the damage, the more tissue factor is released, and the faster clotting occurs. tissue factor then combines with calcium and another clotting factor to form an enzyme complex capable of activating factor x, the first step in the common pathway. Common Pathway: the common pathway begins when enzymes from either the extrinsic or intrinsic pathway activate factor x. activated factor x activates a complex cold prothrombin activator. prothrombin activator converts the proenzyme prothrombin into the enzyme thrombin. thrombin then completes the clotting process by converting fibrinogen to fibrin. Intrinsic Pathway: the intrinsic pathway begins with the activation of proenzymes exposed to collagen fibers at the injury site. The pathway precedes with the assistance of PF-3, a platelet factor released by aggregating platelets. after a series of linked reactions, activated clotting factors combine to form an enzyme complex capable of activating factor x. Clot Reaction: once the fibrin meshwork is form, platelets and blood red cells stick to the fibrin strands. The platelets then contract, and the entire clock begins to undergo clot retraction, a process that continues over a. of 30 to 60 minutes and pulls the cut edges together. as repairs proceed the clot gradually dissolves. this process, called fibrinolysis, begins with the activation of the proenzyme plasminogen by thrombin, produced by the common pathway, and tissue plasminogen activator (t-PA) , released by damaged tissues. The activation of plasminogen produces the enzyme plasmin, which erodes the foundation of the clot.
events occurring in the kidney
the kidneys excrete some hemoglobin, as well as urobilins, which gives urine its yellow color. The presence of intact rbc's in urine - a clinical sign called hematuria - occurs only after urinary tract damage.
Hematocrit (Hct)
the percentage of formed elements in a sample of whole blood. red blood cells make up 99.9% of these formed elements. in adult males the normal hematocrit, or packed cell volume (PCV) averages 47 (range: 37-47). the difference in hematocrit between the sexes primarily reflects the fact that androgens (male hormones) stimulate red blood cell production, whereas estrogens (female hormones) do not.
platelet phase of hemostasis
the platelet phase of homeostasis begins with the attachment of platelets to sticky end of figlio surfaces, the basement membrane, exposed collagen fibers, and each other. chemicals released by activated platelets: (ADP, PDFG, Ca2+, platelet factors) - adenosine diphosphate (ADP) , which stimulates platelet aggregation and secretion. - several chemicals that stimulate vascular spasms - platelet factors, proteins that play a role in blood clotting - platelet derived growth factor (pdgf) , a peptide that promotes vessel repair - calcium ions (CA 2 +) , which are required for platelet aggregation and in several steps in the clotting process.
blood disorders can be classified by their origins and the changes in blood characteristics:
the procedure called venipuncture is crucial in diagnosing blood disorders. Fresh whole blood is generally collected from a superficial vein, such as the median cubital vein on the interior surface of the elbow. venipuncture is commonly used because (1) superficial veins are easy to locate, (2) the walls of veins are thinner than those of comparably sized arteries, and (3) blood pressure in the venous system is relatively low, so the puncture wounds heals quickly. The most common clinical procedures examine venous blood. blood disorders can have a variety of causes. The major categories of blood disorders are: nutritional blood disorders congenital blood disorders blood infections blood cell cancers degenerative blood disorders
Homeostasis
the process of homeostasis, the stopping of bleeding, helps blood loss through the walls of damaged vessels. at the same time, it establishes a framework for tissue repairs. homeostasis has three phases - vascular, platelet, and coagulation - in which many events happen at once, and all of them interact to some degree.
