Histology - Blood and Bone Marrow

what is a specialized connective tissue consisting of cells and extracellular fluid material (plasma)?

blood

how much is the total amount of circulating blood?

5 liters

what makes up the cellular/formed elements of blood?

erooythrocytes (red blood cells), leukocytes (white blood cells), and platelets

plasma consists of what?

plasma proteins (such as fibrinogens, globulins, and albumin) and ground substance (serum)

bone marrow is what?

highly vascularized tissue in the medullary cavities of bone

what does bone marrow consist of?

vascular and hematopoietic (blood-forming) compartments

both blood and bone marrow derive from what?

mesoderm

in the first few weeks of gestation, hematopoiesis occurs where?

in yolk sac

during rest of fetal life until about 2 weeks after birth, blood cells form where?

in liver and spleen

after a person is 2 weeks old, where does blood mostly form?

in bone marrow

where are lymphocytes produced?

in lymphoid organs

what is used to prevent clotting when blood is separated by centrifugation into layers?

an anticoagulant (such as heparin)

what is the heaviest part of blood?

hematocrit

what comprises the hematocrit?

erythrocytes

what contains hemoglobin?

erythocytes

what is hemoglobin?

a protein in blood which carries oxygen

what is found between the hematocrit and plasm?

a thin, gray/white buffy coat

what does the buffy coat consist of?

leukocytes and platelets

why do the buffy coat and plasma float to the top after centrifugation?

because they are less dense than hematocrit

what is the distributing vehicle transporting oxygen, carbon dioxide, metabolites, and hormones throughout the body?

blood

what is the pH of plasma?

about 7.4

what are blood smears often stained with?

mixtures of acidic (eosin) and basic (methylene blue) dyes

the size of red blood cells is what?

very uniform

what is the condition of having a concentration of erythrocytes below the normal range?

anemia

what are the symptoms of anemia?

lethargy, shortness of breath, fatigue, pallor

what describes sickle cell anemia?

due to animo acid substitution, red blood cells are “sickle-shaped,” leading to possible capillary blockage

what is the shape of normal red blood cells?

biconcave

what is the purpose of the bioconcave shape of red blood chells?

provides large surface to volume ration and facilitates gas exchange

red blood cells are called what?

erythrocytes

what is a quality of erythrocytes?

flexible, allowing them to move through capillaries

in larger vessels, red blood cells may adhere to one another loosely in stacks called what?

“rouleax”

how long do erythrocytes normally survive in circulation?

120 days

what happens once erythrocytes reach the end of their life span?

defects in the shape of the cell or in the surface saccharide complexes will have occurred

how are erythrocytes removed from circulation?

by macrophages

what are white blood cells called?

leukocytes

what are one of the body’s chief defenses against infection?

leukocytes

what cells are generally inactive while circulating in blood?

leukocytes

what do leukocytes do when called to sites of infection?

they cross of walls of venules (small veins), become motile, and migrate into tissue

what are the two groups of leukocytes?

granulocytes and agranulocytes

what describes granulocytes?

polymorphic nuclei with one or more distinct lobes

what are the types of granulocytes?

neutrophils, eosinophils, and basophils

what is the life span of granulocytes?

only a few days after leaving blood stream

what describes agranulocytes?

lack specific granules, nuclei are spherical or indented but not lobulated

what are the types of agranulocytes?

lymphocytes and monocytes

what are the most abundant leukocytes?

neutrophils

the nucleus of neutrophils is often what?

“mickey mouse ear” shaped

what is seen in people with inactive X chromosomes (either XX females or XXY males)?

a Barr body, which is a drumstick shaped lobe that can be seen on neutrophils

how much of circulating leukocytes are neutrophils?

50-70%

what describes neutrophil cytoplasm?

lightly eosinophilic and contains granules

what are usually the first leukocytes to arrive at sites of infection?

neutrophils

leukocytes are associated with what kind of infection?

acute infection

what increases in acute bacterial infections?

neutrophil numbers

what do apoptotic neutrophils, bacteria, semidigested material, and tissue form what?

a vicious yellow collection of fluid called pus

what leukocytes are the same size or larger than neutrophils?

eosionphils

what is a characteristic of eosinophils?

bilobed nucleus

what is the main histological identifying feature of eosinophils?

abundant granules that stain pink or red

eosinophils are what?

specific and at to kill parasitic worms

what do eosinophils modulate?

inflammatory response triggered by allergies

where are eosinophils abundant?

in connective tissue of intestinal lining at sites of chronic inflammation such as lungs of patients with asthma or intestinal tract in patients with GI disorders

what is less than one percent of circulating leukocytes?

basophils

what describes basophils?

nucleus divided into two irregular lobes, but is difficult to see because the large granules obscure the nucleus

why is the nucleus of basophils hard to see?

because the large granules obscure the nucleus

basophils represent what?

the presence of heparin and histamine (mediators of inflammation)

what supplements the function of mast cells, which also secrete heparin and histamine?

basophils

what are components of anaphylactic shock?

basophils and mast cells

what describes how basophils and mast cells play a role in anaphylactic shock

these cells rapidly degranulate, producing vasodilation, a drop in blood pressure, and other serious complications which can be fatal

what are the most numerous agranulocyte in blood smears?

lymphocytes

what describes the nucleus of lymphocytes?

very large, spherical nuclei

what can be subdivided into functional groups based on “clusters of differentiation” (distinct surface molecules)?

mature lymphocytes

what are the types of lymphocytes?

• B lymphocytes

• T lymphocytes

• natural killer (NK) cells

where do B cells differentiate?

in the bone marrow

where do T cells differentiate?

in the thymus

what do B cells express?

surface markers

when B cells are activated by antigen, what happens?

they differentiate into plasma cells

what describes the lifespan of lymphocytes?

vary in lifespan, according to specific function

what are the cells involved in lymphoma?

lymphocytes

what are the precursors of macrophages, osteoclasts, microglia, and other cells of mononuclear phagocyte system?

monocytes

what is the most relevant monocyte derivative for us?

macrophage

what describes the shape of nuclei of monocytes?

distinctly indented C-shaped nuclei

______________ are antigen-presenting cells.

monocytes

what has more granular, less dense chromatin in nucleus compared to lymphocytes?

monocytes

what are the types of leukocytes in order of abundance from most to least?

• neutrophils

• lymphocytes

• monocytes (macrophages)

• eosinophils

• basophils

what describes platelets?

small, non-nucleated, membrane-bound cell fragments

what is another name for platelets?

thrombocytes

what cells arise from megakaryoctyes in the bone marrow?

platelets

platelets promote and help what?

blood clotting and repairing tears in small vessels

what is the lifespan of platelets?

about 10 days

an immediate, anaphylactic type response is associated with what type of hypersensitivity response?

type 1

what does anaphylactic refer to?

the response is rapidly evolving, generalized, and involves multiple organ systems

type 1 hypersensitivity response is mediated by what?

IgE antibodies

what does IgE cause?

mast cells and basophils to degranulate

what happens when mast cells and basophils degranulate?

they release histamine and heparin

type II hypersensitivity response is considered what?

cytotoxic

what is type II hypersensitivity response mediated by?

IgM and IgG

what describes the onset of type II hypersensitivity response?

hours to days

in type II hypersensitivity response, how are cells killed?

by complement cascade and phagocytosis

what is an example of type II hypersensitivity response?

hemolytic anemia in newborns or transfusions with mismatched blood

type III hypersensitivity response is considered what?

immune complex-mediated

what is type III hypersensitivity response mediated by?

IgG, complement cascade, and neutrophils

what describes the onset of type III hypersensitivity response?

1-3 weeks