Chapter 19 Blood Flashcards
Blood contributes to homeostasis by
transporting oxygen, carbon dioxide, nutrients, and hormones to and from your body’s cells. It also helps regulate body pH and temperature, and provides protection against disease through phagocytosis and the production of antibodies.
The cardiovascular system (cardio- = heart; vascular = blood vessels) consists of three interrelated components which are
blood, the heart, and blood vessels
hematology is
The branch of science concerned with the study of blood, blood-forming tissues, and the disorders associated with them
Blood is
a liquid connective tissue that consists of cells surrounded by a liquid extracellular matrix.
Interstitial fluid is
the fluid that bathes body cells (see Figure 27.1) and is constantly renewed by the blood.
What are the three funcrions of blood
Transportation
Regulation
and Protection
Describe how blood functions in transportation
blood transports inhaled oxygen from the lungs to the cells of the body and carbon dioxide from the body cells to the lungs for exhalation. It carries nutrients from the digestive canal to body cells and hormones from endocrine glands to other body cells. Blood also transports heat and waste products to various organs for elimination from the body.
Describe how blood functions in regulation
Circulating blood helps maintain homeostasis of all body fluids. Blood helps regulate pH through the use of buffers (chemicals that convert strong acids or bases into weak ones). It also helps adjust body temperature through the heat-absorbing and coolant properties of the water (see Section 2.4) in blood plasma and its variable rate of flow through the skin, where excess heat can be lost from the blood to the environment. In addition, blood osmotic pressure influences the water content of cells, mainly through interactions of dissolved ions and proteins.
Describe how blood functions in protection
Blood can clot (become gel-like), which protects against its excessive loss from the cardiovascular system after an injury. In addition, its white blood cells protect against disease by carrying on phagocytosis. Several types of blood proteins, including antibodies, interferons, and complement, help protect against disease in a variety of ways.
Describe the texture of blood
Blood is denser and more viscous (thicker) than water and feels slightly sticky.
what is the normal temperature of blood
38 Celsius
What is the pH range for normal blood
7.35-7.45
The color of blood varies based on
oxygen content
Bright red blood is
saturated with Oxygen
Dark red blood is
unsaturated with oxygen
Blood constitutes about _________ of extracellular fluid, amounting to ______________ of the total body mass.
20%
8%
In a male the average blood volume is
5-6 liters
In a female the average blood volume is
4-5 liters
Several hormones, regulated by negative feedback, ensure that
blood volume and osmotic pressure remain relatively constant.
which hormones regulate how much water is excreted in the urine
aldosterone, antidiuretic hormone, and atrial natriuretic peptide,
Complete blood count (CBC) is
one of the most common blood tests and is often done as part of a regular checkup. It measures the number and size of red blood cells, hemoglobin, and hematocrit; the number and percentage of each type of white blood cell in a sample of 100 cells (differential white blood cell count); and the number of platelets.
Basic metabolic panel refers to
a group of tests that measure the levels of different chemicals in blood. Included are glucose, calcium, various electrolytes, blood urea nitrogen, and creatinine.
Blood enzyme tests. are used to
determine the levels and activity of certain enzymes as indicators of organ damage. For example, higher levels of creatine kinase and troponin indicate damage to the heart and skeletal muscles, while higher levels of ALT and AST indicate liver damage.
Lipoprotein panels are
several tests that assess the risk of heart disease. Among the blood components measured are total cholesterol, HDL, LDL, and triglycerides.
What are the two components of blood
blood plasma
formed elements
What is blood plasma,
a watery liquid extracellular matrix that contains dissolved substances,
What are formed elements,
cells and cell fragments.
Blood is about 55% ___________ and 45% ___________________
blood plasma
formed elements
99 percent of formed elements are
RBC’s
Pale, colorless white blood cells (WBCs) and platelets occupy
less than 1% of the formed elements.
buffy coat
layer of WBC’s between the packed RBCs and blood plasma in centrifuged blood
When the formed elements are removed from blood
, a straw-colored liquid called blood plasma (or simply plasma) is left.
Blood plasma is about _______________ water and ____________ solutes
91.5%
8.5%
What are blood plasma protiens
proteins that are confined to blood
Blood palsma proteins include
the albumins (al′-BŪ-mins) (54% of blood plasma proteins), globulins (GLOB-ū-lins) (38%), and fibrinogen (fī-BRIN-ō-jen) (7%).
Certain blood cells develop into plasmocytes that produce gamma globulins, an important type of globulin
These blood plasma proteins are also called antibodies or immunoglobulins (im′-ū-nō-GLOB-ū-lins) because they are produced during certain immune responses.
What is an antigen
Foreign substances such as bacteria and viruses stimulate production of millions of different antibodies
The formed elements of the blood include three principal components:
red blood cells, white blood cells, and platelets (Figure 19.2).
RBC’s function is to
transport oxygen from the lungs to body cells and deliver carbon dioxide from body cells to the lungs.
White blood cells (WBCs) or leukocytes function is to
protect the body from invading pathogens and other foreign substances.
Platelets
Fractions of cells that release chemicals that promote blood clotting when blood vessels are damaged. Platelets are the functional equivalent of thrombocytes, nucleated cells found in lower vertebrates that prevent blood loss by clotting blood.
Platelets are the functional equivalent of
thrombocytes, nucleated cells found in lower vertebrates that prevent blood loss by clotting blood.
hematocrit
The percentage of total blood volume occupied by RBCs
The normal range of hematocrit
for adult females is 38–46% (average = 42); for adult males, it is 40–54% (average = 47)
The hormone testosterone, present in much higher concentration in males than in females, stimulates synthesis of
erythropoietin (EPO), the hormone that in turn stimulates production of RBCs
A significant drop in hematocrit indicates
anemia, a lower-than-normal number of RBCs
In polycythemia (pol′-ē-sī-THĒ-mē-a)
the percentage of RBCs is abnormally high, and the hematocrit may be 65% or higher. This raises the viscosity of blood, which increases the resistance to flow and makes the blood more difficult for the heart to pump. Increased viscosity also contributes to high blood pressure and increased risk of stroke.
Causes of polycythemia include
abnormal increases in RBC production, tissue hypoxia, dehydration, blood doping, or the use of erythropoietin by athletes.
The liquid portion of blood is
water
What is the function of water in blood
Solvent and suspending medium. Absorbs, transports, and releases heat.
Where are blood plasma protiens generally produced
Liver
What is the function of blood plasma protiens
Responsible for colloid osmotic pressure. Major contributors to blood viscosity. Transport hormones (steroid), fatty acids, and calcium. Help regulate blood pH
Describe albumins
Smallest and most numerous plasma proteins.
What is the function albumins
Help maintain osmotic pressure, an important factor in the exchange of fluids across blood capillary walls.
Describe globulins
Large proteins (plasmocytes produce immunoglobulins).
What is the function of globulins
Immunoglobulins help attack viruses and bacteria. Alpha and beta globulins transport iron, lipids, and fat-soluble vitamins.
Fibrinogen is
a large blood plasma protien that plays an essential role in clotting
What are some of the electrolytes found in blood plasma
Inorganic salts; positively charged (cations) Na+, K+, Ca2+, Mg2+; negatively charged (anions) Cl−, HPO42−, SO42−, HCO3−.
What is the function of electrolytes in plasma
Help maintain osmotic pressure and play essential roles in cell functions.
Describe the nutrients found in blood plasma
Products of digestion, such as amino acids, glucose, fatty acids, glycerol, vitamins, and minerals.
What is the function of blood plasma
Essential roles in cell functions, growth, and development.
What gases are found in blood plasma
Oxygen
Carbon dioxide
Nitrogen
Oxygen in blood plasma
is important to many cellular functions
What is the function of Carbon Dioxide in blood
Involved in the regulation of blood pH.
Nitrogen in blood plasma
has no known function
What regulatory substances are in blood plasma
Enzymes
Hormones
Vitamins
What is the function of enzymes in plasma
They catalze chemical reactions
What is the functions of hormones in plasma
Regulate metabolism, growth, and development.
What is the function of vitamins in blood plasma
Cofactors for enzymatic reactions.
What waste products exist in blood plasma
Urea, uric acid, creatine, creatinine, bilirubin, ammonia.
Why do waste products appear in plasma
Most are breakdown products of protein metabolism that are carried by the blood to organs of excretion.
Negative feedback systems regulate
the total number of RBCs and platelets in circulation, and their numbers normally remain steady
The abundance of the different types of WBCs
varies in response to challenges by invading pathogens and other foreign antigens
hemopoiesis (hēm-ō-poy-Ē-sis; -poiesis = making) or hematopoiesis.
The process by which the formed elements of blood develop
Red bone marrow becomes
the primary site of hemopoiesis in the last 3 months before birth, and continues as the source of blood cells after birth and throughout life.
Red bone marrow
is a highly vascularized connective tissue located in the microscopic spaces between trabeculae of spongy bone tissue.
About 0.05–0.1% of red bone marrow cells are called
multipotent (mul-TIP-ō-tent; multi = many) stem cells or hemocytoblasts and are derived from mesenchyme (tissue from which almost all connective tissues develop). These cells have the capacity to develop into many different types of related cells
Under certain conditions, such as severe bleeding,
yellow bone marrow can revert to red bone marrow; this occurs as blood-forming stem cells from red bone marrow move into yellow bone marrow, which is then repopulated by multipotent stem cells.
As an individual ages,
the rate of blood cell formation decreases; red bone marrow in the medullary cavity of long bones becomes inactive and is replaced by yellow bone marrow, which consists largely of fat cells.
Multipotent stem cells in red bone marrow
reproduce themselves, proliferate, and differentiate into cells that give rise to blood cells, macrophages, reticular cells, mast cells, and adipocytes
After blood cells form,
they enter the sinuses and other blood vessels and leave the bone through nutrient and periosteal veins
With the exception of lymphocytes, formed elements do not
divide once they leave red bone marrow.
In order to form blood cells, multipotent stem cells in red bone marrow
produce two further types of stem cells, which have the capacity to develop into several types of cells. These stem cells are called myeloid stem cells and lymphoid stem cells
Myeloid stem cells begin their development
in red bone marrow
Myeloid stem cels give rise to
red blood cells, platelets, monocytes, neutrophils, eosinophils, basophils, and mast cells.
Lymphoid stem cells give rise to
Lymphocytes and natural killer cells
During hemopoiesis, some of the myeloid stem cells differentiate into
progenitor cells
Progenitor cells are no longer capable of
reproducing themselves and are committed to giving rise to more specific elements of blood.
Some progenitor cells are known as
colony-forming units
CFU–E ultimately produces
erythrocytes (red blood cells)
CFU–Meg produces
megakaryocytes the source of platelets
CFU–GM ultimately produces
granulocytes (specifically, neutrophils) and monocytes
Progenitor cells and stem cells
resemble lymphocytes and cannot be distinguished by their microscopic appearance alone.
bone marrow aspiration
withdrawal of a small amount of red bone marrow with a fine needle and syringe
bone marrow biopsy
removal of a core or cylindrical sample of red bone marrow with a larger needle
progenitor cells give rise to
precursor cells, also known as blasts
Precursor cells have
recognizable microscopic appearances.
Several hormones called hemopoietic growth factors (hē-mō-poy-ET-ik) regulate
the differentiation and proliferation of particular progenitor cells.
Erythropoietin (EPO) (e-rith′-rō-POY-ē-tin) functions to
Erythropoietin (EPO) (e-rith′-rō-POY-ē-tin) increases the number of red blood cell precursors
Erythropoietin abbreviation
EPO
EPO is produced primarily by cells in the
kidneys that lie between the kidney tubules
With renal failure,
EPO release slows and RBC production is inadequate. This leads to a decreased hematocrit, which leads to a decreased ability to deliver oxygen to body tissues.
Thrombopoietin (TPO) (throm′-bō-POY-ē-tin)
is a hormone produced by the liver that stimulates the formation of platelets from megakaryocytes.
Thrombopoietin abbreviation
(TPO)
Cytokines (SĪ-tō-kīns) are
small glycoproteins that are typically produced by cells such as red bone marrow cells, leukocytes, macrophages, fibroblasts, and endothelial cells.
Cytokines function is to
stimulate proliferation of progenitor cells in red bone marrow and regulate the activities of cells involved in nonspecific defenses (such as phagocytes) and immune responses
Two important families of cytokines that stimulate white blood cell formation are
colony-stimulating factors (CSFs) and interleukins
Cytokines generally act as
local hormones
Red blood cells (RBCs) or erythrocytes (e-RITH-rō-sīts; erythro- = red; -cyte = cell) contain
the oxygen-carrying protein hemoglobin, which is a pigment that gives whole blood its red color
To maintain normal numbers of RBCs,
new mature cells must enter the circulation at the astonishing rate of at least 2 million per second, a pace that balances the equally high rate of RBC destruction.
Describe the shape of RBC’s
RBCs are biconcave discs with a diameter of 7–8 μm
RBC’s plasma membranes are
both strong and flexible, which allows them to deform without rupturing as they squeeze through narrow blood capillaries.
RBCs lack
a nucleus and other organelles and can neither reproduce nor carry on extensive metabolic activities.
The cytosol of RBCs contains
hemoglobin molecules; these important molecules are synthesized before loss of the nucleus during RBC production and constitute about 33% of the cell’s weight.
Red blood cells are highly specialized for
their oxygen transport function.
Because mature RBCs have no nucleus,
all of their internal space is available for oxygen transport
Because RBCs lack mitochondria and generate ATP anaerobically (without oxygen),
they do not use up any of the oxygen they transport.
Why are RBC´s biconcave discs
A biconcave disc has a much greater surface area for the diffusion of gas molecules into and out of the RBC than would, say, a sphere or a cube.
A hemoglobin molecule consists of a protein called
globin
globin is
composed of four polypeptide chains (two alpha and two beta chains); a ringlike nonprotein pigment called a heme (Figure 19.4b) is bound to each of the four chains.
How is hemoglobin able to attach to four oxygen molecules
At the center of each heme ring is an iron ion (Fe2+) that can combine reversibly with one oxygen molecule (Figure 19.4c), allowing each hemoglobin molecule to bind four oxygen molecules.
Each oxygen molecule picked up from the lungs
is bound to an iron ion.
As blood flows through tissue capillaries,
the iron–oxygen reaction reverses. Hemoglobin releases oxygen, which diffuses first into the interstitial fluid and then into cells.
Hemoglobin also transports
about 23% of the total carbon dioxide, a waste product of metabolism.
Blood flowing through tissue capillaries picks up
carbon dioxide, some of which combines with amino acids in the globin part of hemoglobin.
As blood flows through the lungs, the carbon dioxide is
released from hemoglobin and then exhaled.
In addition to its key role in transporting oxygen and carbon dioxide, hemoglobin also plays a role in
the regulation of blood flow and blood pressure
The gaseous hormone nitric oxide (NO), produced by the endothelial cells that line blood vessels,
binds to hemoglobin.
Under some circumstances, hemoglobin releases NO. The released NO causes
vasodilation, an increase in blood vessel diameter that occurs when the smooth muscle in the vessel wall relaxes.
Vasodilation
improves blood flow and enhances oxygen delivery to cells near the site of NO release
Red blood cells also contain the enzyme carbonic anhydrase (CA), which
catalyzes the conversion of carbon dioxide and water to carbonic acid, which in turn dissociates into H+ and HCO3−
carbonic anhydrase (CA) catalyzes the conversion of carbon dioxide and water to carbonic acid, which in turn dissociates into H+ and HCO3−. The entire reaction is reversible.This reaction is significant for two reasons:
(1) It allows about 70% of CO2 to be transported in blood plasma from tissue cells to the lungs in the form of HCO3− (see Chapter 23). (2) It also serves as an important buffer in extracellular fluid (see Chapter 27).
Red blood cells live
only about 120 days because of the wear and tear their plasma membranes undergo as they squeeze through blood capillaries.
Without a nucleus and other organelles,
RBCs cannot synthesize new components to replace damaged ones
The plasma membrane of RBC´s
becomes more fragile with age, and the cells are more likely to burst, especially as they squeeze through narrow channels in the spleen
Ruptured red blood cells are
removed from circulation and destroyed by resting phagocytic macrophages in the spleen and liver
What is the first step in the recycling of dead RBC´S
Macrophages in the spleen, liver, or red bone marrow phagocytize ruptured and worn-out red blood cells
In the RBC recylcling process, after Macrophages in the spleen, liver, or red bone marrow phagocytize ruptured and worn-out red blood cells
The globin and heme portions of hemoglobin are split apart
In the RBC recylcling process, after The globin and heme portions of hemoglobin are split apart what happens to globin
Globin is broken down into amino acids, which can be reused to synthesize other proteins.
In the RBC recylcling process, after The globin and heme portions of hemoglobin are split apart. what happens to the heme portion
Iron is removed from the heme portion in the form of Fe3+, which associates with the plasma protein transferrin (trans-FER-in; trans- = across; -ferr- = iron), a transporter for Fe3+ in the bloodstream.
In the RBC recylcling process, after Iron is removed from the heme portion in the form of Fe3+, which associates with the plasma protein transferrin
In the RBC recylcling process, after In muscle fibers, liver cells, and macrophages of the spleen and liver, Fe3+ detaches from transferrin and attaches to an iron-storage protein called ferritin (FER-i-tin).
In the RBC recylcling process, after Fe3+ detaches from transferrin and attaches to an iron-storage protein called ferritin (FER-i-tin).
On release from a storage site or absorption from the digestive canal, Fe3+ reattaches to transferrin.
In the RBC recylcling process after Fe3+ reattaches to transferrin.
The Fe3+–transferrin complex is then carried to red bone marrow, where RBC precursor cells take it up through receptor-mediated endocytosis (see Figure 3.12) for use in hemoglobin synthesis. Iron is needed for the heme portion of the hemoglobin molecule, and amino acids are needed for the globin portion. Vitamin B12 is also needed for the synthesis of hemoglobin.
In the RBC recycling process after The Fe3+–transferrin complex is carried to red bone marrow, where RBC precursor cells take it up through receptor-mediated endocytosis (see Figure 3.12) for use in hemoglobin synthesis.
Erythropoiesis in red bone marrow results in the production of red blood cells, which enter the circulation.
In the RBC recycling process What happens to the non-iron portion of heme
the non-iron portion of heme is converted to biliverdin (bil-ē-VER-din), a green pigment, and then into bilirubin (bil-ē-ROO-bin), a yellow-orange pigment.
In the RBC recycling process after the non-iron portion of heme is eventually converted to bilirubin (bil-ē-ROO-bin)
Bilirubin enters the blood and is transported to the liver.
In the RBC recycling process after Bilirubin enters the blood and is transported to the liver.
Within the liver, bilirubin is released by liver cells into bile, which passes into the small intestine and then into the large intestine.
In the RBC recycling process after bile passes into the small intestine and then into the large intestine.
In the large intestine, bacteria convert bilirubin into urobilinogen (ūr-ō-bī-LIN-ō-jen)
In the RBC recycling process after bacteria convert bilirubin into urobilinogen (ūr-ō-bī-LIN-ō-jen)
Some urobilinogen is absorbed back into the blood, converted to a yellow pigment called urobilin (ūr-ō-BĪ-lin), and excreted in urine. Most urobilinogen is eliminated in feces in the form of a brown pigment called stercobilin (ster′-kō-BĪ-lin), which gives feces its characteristic color.
The rate of RBC formation by red bone marrow equals
the rate of RBC destruction by macrophages.
Because free iron ions (Fe2+ and Fe3+) bind to and damage molecules in cells or in the blood
transferrin and ferritin act as protective “protein escorts” during transport and storage of iron ions
Erythropoiesis (e-rith′-rō-poy-Ē-sis), the production of RBCs, starts in
the red bone marrow with a precursor cell called a proerythroblast (prō-e-RITH-rō-blast)
a proerythroblast divides several times, producing cells that
begin to synthesize hemoglobin
Ultimately, a cell near the end of the development sequence
ejects its nucleus and becomes a reticulocyte
Loss of the nucleus in RBC’s causes
the center of the cell to indent, producing the red blood cell’s distinctive biconcave shape.
Reticulocytes pass from red bone marrow into the bloodstream by
squeezing between plasma membranes of adjacent endothelial cells of blood capillaries.
Reticulocytes develop into
mature red blood cells within 1 to 2 days after their release from red bone marrow.
The rate of erythropoiesis is measured by a
reticulocyte count.
Normally, erythropoiesis and red blood cell destruction
proceed at roughly the same pace
If the oxygen-carrying capacity of the blood falls because erythropoiesis is not keeping up with RBC destruction,
a negative feedback system steps up RBC production
hypoxia
An oxygen deficiency at the tissue level
hypoxia may occur if
too little oxygen enters the blood.
hypoxia stimulates
the kidneys to step up the release of erythropoietin, which speeds the development of proerythroblasts into reticulocytes in the red bone marrow.
As the number of circulating RBCs increases
more oxygen can be delivered to body tissues.
Premature newborns often exhibit
anemia, due in part to inadequate production of erythropoietin.
During the first weeks after birth,
the liver, not the kidneys, produces most EPO.
Because fetal hemoglobin (hemoglobin present at birth) carries up to 30% more oxygen,
the loss of fetal hemoglobin, due to insufficient erythropoietin production, makes the anemia worse.
Unlike red blood cells, white blood cells (WBCs) or leukocytes (LOO-kō-sīts; leuko- = white)
have nuclei and a full complement of other organelles but they do not contain hemoglobin.
Granular leukocytes include
neutrophils, eosinophils, and basophils;
agranular leukocytes include
lymphocytes and monocytes