Exam 1: Blood

Question 1

Components of Blood

Answer 1

• formed elements: cells and all things derived from them
• — erythrocytes, leucocytes, platelets
• plasma
• proteins, ions (electrolytes), nutrients, gases, waste products et al.

Question 2

Physical Characteristics of Blood

Answer 2

• viscous
• temperature: about 38°
• arterial blood has a pH of 7.35 – 7.45.
• — slightly alkaline

Question 3

Functions of Blood

Answer 3

• distribution functions: transport of O2, nutrients, metabolic waste (urea, CO2), and hormones
• regulatory functions: body temperature, pH, fluid volume
• protective functions: preventing blood loss, preventing infection (antibodies, WBC’s, Complement)

Question 4

Plasma

Answer 4

• serum + clotting factors
• – serum: plasma without the clotting factors/proteins
• is over 90% water
• makes up over half of blood
• over 100 different dissolved solutes
• – mostly proteins
• – albumin is the most abundant plasma protein
• contains globulins
• — alpha, beta, and gamma

Question 5

Albumin

Answer 5

• most abundant plasma protein (58%)
• carrier: assisting other molecules through the circulation
• an important buffer to maintain pH
• helps maintain osmotic pressure

Question 6

Gamma Globulin

Answer 6

• include antibodies
• important for immune function
• make up about 38% of all globulins

Question 7

Erythrocytes

Answer 7

• red blood cells
• made in red bone marrow
• – found in spongy bone (caps of long bones and flat bones)
• anucleate, biconcave discs containing hemoglobin
• function in the transport of respiratory gases, deliver oxygen to cells

Question 8

Hematocrit

Answer 8

• percentage of total blood volume made up of RBC’s
• — usually about 45%
• centrifuge blood
• — RBCs go to the bottom bc they are heaviest - fill the bottom 45% of test tube
• — white blood cells and platelets are in the middle - but only make up about 1% of blood
• — plasma is the lightest and fills the top 55% of the test tube

Question 9

Hemoglobin

Answer 9

• a protein consisting of two α and two β polypeptide chains, each of which is bound to a molecule of the pigment heme in the center of the hemoglobin
• – iron is found in the heme
• O2 binds easily and reversibly to the iron in the heme so each hemoglobin molecule can bind with four molecules of oxygen
• CO2 binds to the globin.

Question 10

Hematopoiesis

Answer 10

• blood cell production
• all formed elements originate from stem cells found in the red bone marrow called hemocytoblasts
• proerythroblasts are committed to becoming RBC’s.

Question 11

Erythropoietin

Answer 11

• hormone that leads to red blood cell production

Question 12

Erythrocytosis (polycythemia)

Answer 12

• too many red blood cells
• blood becomes thick and sluggish, high viscosity
• may lead to blocked capillaries
• often found in smokers
• – not getting enough oxygen, which signals the kidneys to make more red blood cells

Question 13

Red Blood Cell Formation

Answer 13

• hypoxic conditions stimulate certain kidney cells to release erythropoietin hormone
• erythropoietin is transported to the bone marrow and hastens the maturity of RBC’s
• during the maturation process, the nucleus and other organelles are ejected and become stippled reticulocytes which enter the bloodstream
• erythrocytes last about 4 months at which time they are engulfed by macrophages (WBC’s) and are stripped of their iron for reuse.
• — some of the heme is degraded into bilirubin which is picked up by liver cells and secreted in bile.

Question 14

Anemia

Answer 14

• usually defined as a decrease in the amount of red blood cells or hemoglobin in the blood.
• it can also be defined as a lowered ability of the blood to carry oxygen.

Types:

• hemorrhagic anemia
• hemolytic anemia
• aplastic anemia
• iron-deficiency anemia
• pernicious anemia
• thalassemia
• sickle-cell anemia

Question 15

Microcytic vs Macrocytic anemia

Answer 15

• Microcytic: RBCs are smaller than they normally are
• –ex: iron deficiency - iron is hard to absorb, so you preserve it as much as you can while you have it
• Macrocytic: RBCs are larger than they normally are

Question 16

Hemorrhagic Anemia

Answer 16

• refers to loss of blood from the vessels.
• — a wound which leads to significant blood loss from the body
• — or a wound that leads to internal bleeding

Question 17

Hemolytic Anemia

Answer 17

• refers to the rupture of RBC’s.

- – example: malaria - the virus affects red blood cells and causes them to burst when the virus reproduces

Question 18

Aplastic Anemia

Answer 18

• is the inability of bone marrow to manufacture RBC’s

- caused by some antibiotics, but cause is often unknown

Question 19

Iron-Deficiency Anemia

Answer 19

• is the inadequate intake or absorption or loss of Fe necessary to make heme.
• microcytic

Question 20

Pernicious Anemia

Answer 20

• is a deficiency of vitamin B12 necessary for DNA replication and cell division.
• usually people have enough B12 in diet, but not enough intrinsic factor
• — older people are more likely to have pernicious anemia: not producing enough intrinsic factor in their stomach
• — need intrinsic factor to get B12 into the system through the stomach
• B12 is important for mitosis/cell division
• — red bone marrow is a very active site for cell division, so a lack of B12 leads quickly to a lack of red blood cells

Question 21

Thalessemia

Answer 21

• genetic disorder affecting red blood cells
• most commonly found in people of mediterranean descent
• causes the body to make less hemoglobin
• — improper oxygen transport
• — destruction of red blood cells - less circulating red blood cells than there should be

Question 22

Sickle Cell Anemia

Answer 22

• genetic disorders affecting RBC’s.
• african descent
• beta chain is affected by a genetic defect - only one amino acid different from normal cell
• — cause RBC to have a curved (sickle) shape instead of being circular
• RBCs bunch up at beginning of capillary beds and starve tissues of blood

Question 23

Leucocytes

Answer 23

• nucleated
• account for less than 1% of the total blood volume
• — the normal number is from about 4,000 to 11,000 WBC’s per mm3.
• some WBC’s are capable of slipping through capillary walls by amoeboid motion (a process called diapedesis) where they are able to engulf infectious agents by phagocytosis.
• 2 major categories: granulocytes and agranulocytes

Question 24

Granulocytes

Answer 24

• visible cytoplasmic granules
• neutrophils
• eosinophils
• basophils

Question 25

Neutrophils

Answer 25

• cytoplasm stains a lilac color with a mixture of basic and acidic dyes
• the most numerous of the WBC’s (about 60%).
• about twice the size of RBC’s
• have nuclei variably consisting of 3 to 6 lobes
• — polymorphonuclear leukocytes
• phagocytes
• — are able to leave the bloodstream and enter infected tissue where they ingest and destroy bacteria
• the number of neutrophils increases dramatically with acute bacterial infections.

Question 26

Eosinophils

Answer 26

• cytoplasm stains red or orange with the acidic dye eosin
• make up about 1 – 4% of all WBC’s
• has a bilobed nucleus
• their major function is to produce toxic proteins against certain parasitic worms
• they are also important in allergic responses by phagocytizing immune complexes.

Question 27

Basophils

Answer 27

• cytoplasm stains blue-purple with the basic dye methylene blue
• account for

Question 28

Agranulocytes

Answer 28

• Lymphocytes

- Monocytes

Question 29

Lymphocytes

Answer 29

• the second most numerous of the WBC’s (20 to 40%)
• most are not found in the bloodstream, but are enmeshed in lymphoid tissue
• — where they are necessary for the specific immune response
• T cells respond directly against infected cells
• B cells give rise to plasma cells that produce antibodies
• memory cells: responsible for a more immediate reaction to the same antigen at the time of a later infection
• — secondary response
• — both T and B have memory cells
• lymphocytes are the primary constituents of lymphatic tissue
• — this tissue is found in tonsils, lymph nodes and the spleen.

Question 30

Monocytes

Answer 30

• are the largest of the WBC’s
• account for about 2 to 8% of the total
• have a kidney or U-shaped nucleus
• during infections, they leave the blood and migrate to the infected tissue
• — where they differentiate into macrophages (clark kent –> superman)

Question 31

WBCs fight off substances by…

Answer 31

• releasing chemicals such as heparin (an anticoagulant) and histamine (a vasodilator)
• phagocytosis
• antibody production

Question 32

Leukocytosis

Answer 32

• a high number of leucocytes
• — a count of over 11,000/mm3
• occurs normally in response to infection

Question 33

Leukopoiesis

Answer 33

• the production of WBCs
• hemocytoblasts may become
• — lymphoid stem cells: committed to becoming lymphocytes
• — myeloid stem cells: committed to becoming all other types of WBC’s

Question 34

Leukopenia

Answer 34

• a leukocyte disorder

- an abnormally low white blood cell count

Question 35

Leukemia

Answer 35

• a leukocyte disorder

- a cancerous condition involving WBCs

Question 36

B and T cell maturation

Answer 36

• T cell: mature in thymus gland

- B cell: mature in bone marrow

Question 37

Infectious Mononucleosis

Answer 37

• a leukocyte disorder
• is a virus infection of B lymphocytes
• usually seen in teens and young adults
• transmitted through infected saliva.

Question 38

AIDS

Answer 38

• a leukocyte disorder

- a viral infection of T lymphocytes.

Question 39

Platelets

Answer 39

• aka thrombocytes
• are fragments of large cells called megakaryocytes
• thrombopoietin: regulates platelet formation
• normal platelet count is 250,000 to 400,000 per mm3.
• stick to exposed collagen and other platelets in damaged blood vessel walls
• — temporarily forming a plug to protect against blood loss
• — Aspirin makes platelets less sticky.
• release molecules to start the clotting process
• stimulate neutrophils to destroy bacteria.

Question 40

Macrophages

Answer 40

• actively phagocytize pathogens
• — hunters: eat foreign bacteria
• — either wandering: go out and catch food (like a lion)
• — or fixed: lie in wait for the foreign organism to come near (like a spider)
• clean up cellular debris
• — scavengers
• important in activating lymphocytes.

Question 41

ABO Blood Groups

Answer 41

• ABO blood groups are based on the presence or absence of two antigens or agglutinogens
• — specific glycoproteins on the RBC membrane surface
• — type A and type B.
• preformed antibodies called agglutinins act against these two antigens
• — formed during fetal development, do not need to be exposed to the antigen to have the antibody to it
• — found in the plasma
• — anti-A and anti-B
• a person possesses agglutinins for the type of antigen that is not found on her RBC membrane
• — type A blood has A antigen and anti-B agglutinins
• — type B blood has B antigen and anti-A agglutinins
• a person with neither antigen is Type O
• — and has both anti-A and anti-B agglutinins
• a person with both antigens is Type AB
• — and has neither anti-A nor anti-B agglutinins

Question 42

If a blood transfusion is given to someone with a different ABO blood type….

Answer 42

If RBC’s with certain antigens are transfused into blood containing antibodies against those antigens, a clumping or agglutination will occur and may be fatal

• Type O is called the universal donor
• — since there is no antigen to attack, all types will accept this blood
• Type AB is called the universal receiver since no antibodies occur in the plasma.
• — AB blood recognizes both A antigens and B antigens as belonging to self

Question 43

Rh Blood Type

Answer 43

• People carrying the Rh antigen on their RBC membrane are called Rh+, those without the antigen are called Rh-
• . No preformed antibodies in the plasma, but a transfusion involving Rh+ to an Rh- recipient stimulates antibody production in the recipient
• — no reaction takes place the first time because antibodies build up very slowly
• But on subsequent exposures to the antigen, hemolysis occurs.
• — Untreated, a second pregnancy involving an Rh- mother and an Rh+ fetus may result in abortion because of the mother’s immediate immune response to the mixing of maternal and fetal blood
• — this is called hemolytic disease of the newborn

Question 44

Coagulation

Answer 44

• Blood clotting is a complex, multistep process that results in a complex substance called prothrombin activator being formed
• — prothrombin activator converts a plasma protein called prothrombin into an enzyme called thrombin.
• — vitamin K is necessary for the activation of prothrombin.
• Thrombin catalyzes the joining of fibrinogen molecules (present in the plasma) to a fibrin mesh
• — the fibrin mesh traps blood cells and effectively seals the hole until the blood vessel can be permanently repaired.

Question 45

1. Thrombus

2. Embolus

Answer 45

1. a clot that forms and persists in an unbroken blood vessel
2. a thrombus that has broken away and is floating freely in the bloodstream

Question 46

1. Clotting Factors

2. Anticoagulants

Answer 46

1. Factors that enhance clot formation

2. Factors that inhibit clotting

Question 47

1. thrombocytopenia
2. impaired liver function occurs when
3. hemophilia

Answer 47

1. a deficiency of circulating platelets
2. the liver is unable to synthesize some of the clotting factors.
3. refers to several hereditary bleeding disorders in which certain clotting factors are missing
   - — a sex-linked disease causing a deficiency of factor VIII is the most common

Question 48

Diagnostic blood tests

Answer 48

• a differential white blood cell count may indicate the kind of infection involved.
• prothrombin time assesses the amount of prothrombin present in the blood.
• a SMAC (Sequential Multiple-channel Analyzer Computer) is a blood chemistry profile.
• a Complete Blood Count (CBC) includes counts of all formed elements as well as hemoglobin and hematocrit