BIOL 204: Blood (chapter 17)

what is blood?

what is blood?

fluid that acts as a transport system for the body

functions of blood

transport, regulation, protection

transport of blood function

Delivering o2 and nutrients to body cells, transporting metabolic. transporting hormones from endocrine organs to target organs

what organs are part of transport of blood?

wastes to lungs and kidneys for elimination

which organs do hormones get transported to?

endocrine organs to target organs

regulation of blood function

maintaining body temperature by absorbing and distributing heat, maintaining normal pH using buffers; alkaline reserve of bicarbonate ions, maintaining adequate fluid volume in circulatory system

what instrument is used to normalize pH?

buffers

protection of blood

preventing blood loss, preventing infection

preventing blood loss

plasma proteins and platelets in blood initiate clot formation

preventing infection

agents of immunity are carried in blood (antibodies, complement proteins, white blood cells= leukocytes)

what agents are carried in blood

antibodies, complement proteins, and WBC’s

blood is the only tissue ______

that is fluid

blood is a mix of

matrix and cellular components

matrix is also?

plasma

cellular components is also?

formed elements

the color of blood varies with

\n o2 content

T/F: de-oxygenated blood is blue

false

what is the pH range of blood

\n 7.35-7.45

volume of blood in males

5-6L

volume of blood in females

4-5L

Red blood cells (RBC)

erythrocytes- 45% of whole blood

what is hematocrit?

percent of blood volume that is erythrocytes

what is buffy coat?

White blood cells and platelets (1%)

white blood cells (WBC)

leukocytes

how much blood is in plasma?

55% in blood

spun tube of blood yields three layers

plasma on top, buffy coat, erythrocytes on bottom

composition of plasma

\n straw-colored sticky fluid, about 90% water

most abundant solutes

plasma proteins

plasma proteins produced mostly by

liver

albumin

makes up 60% of plasma proteins, functions as carrier of other molecules as blood buffer and contributes to plasma osmotic pressure

formed elements

erythrocytes, leukocytes, platelets

leukocytes

complete cells

erythrocytes

no nuclei or organelles

platelets

cell fragments

most formed elements survive in bloodstream for

only a few days

most blood cells originate in

bone marrow and do not divide

what is an erythrocytes

small cells that contribute to gas transport

erythrocytes are filled with

hemoglobin (Hb) for gas transport

hemoglobin

red heme pigment bound to protein globin

globin

is composed of four polypeptide chains

heme pigment

is bonded to each globin chain

-gives blood red color

each heme's central iron atom

binds one o2

each Hb carries

four o2

cycle of Hb

Hb gets o2 in lungs, unloads o2 in tissues, picks up some co2 to release in lungs

hematopoiesis

formation of all blood cells, occurs in red bone marrow

hematopoiesis in adults

found in axial skeleton, girdles, and proximal epiphyses of humerus and femur

hematopoietic stem cells (hemocytoblasts)

stem cells that gives rise to all formed elements

producing erythrocytes takes

15 days

why do some athletes abuse artificial erythropoietin (EPO)

increases hematocrit which increase stamina and performance

dangers of abusing EPO

increasing hematocrit thickens blood which causes clotting, stroke, or heart failure

life span of erythrocytes

100-120 days

erythrocyte do not

grow, divide, make new proteins

when erythrocytes are aged

become fragile, Hb degenerates

macrophages in spleen

break down these RBCs

two erythrocyte disorders

anemia and polycythemia

anemia

blood does not carry enough o2

cause of anemia

blood loos, not enough RBCs produced, too many RBCs being destroyed

hemorrhagic anemia

rapid blood loss- trauma

chronic hemorrhagic anemia

slight but persistent blood loss

not enough RBCs produced

iron-deficiency anemia, low iron intake, poor absorption, kidney disfunction

too many RBCs destroyed

premature lysis of RBCs, incompatible transfusions or infections

sickle cell anemia

sickle cell anemia

RBCs become crescent shaped when o2 levels are low, misshape RBCs rupture easily and block small vessels

polycythemia

excess of RBCs; increases blood viscosity, causing blood flow

polycythemia vera

bone marrow cancer leading to excess RBCs, hematocrit may go as high as 80%

treatment for polycythemia vera

therapeutic phlebotomy

secondary polycythemia

caused by low o2 levels (example: high altitude) or increased EPO production

leukocytes

function in defense against disease

leukocytes increase in number

in response to infection

two major categories O leukocytes

granulocytes and agranulocytes

which contain visible cytoplasmic granules (granulocytes or agranulocytes)

granulocytes

granulocytes

larger and shorter lived than RBCs, contain lobed nuclei, all are phagocytic to some degree

life span of granulocytes

hours to days

three types of granulocytes

neutrophils, eosinophils, basophils

neutrophils

most numerous WBCs- 50-70%, kill microbes by process called respiratory burst

eosinophils

2-4% of all leukocytes, Red-staining granules contain digestive

enzymes• Release enzymes on large parasitic worms,

digesting their surface• Also play role in allergies and immune response

basophils

rarest WBCs, 0.5-1%, Nucleus deep purple with one to two

constrictions

Large, purplish black (basophilic) granules

contain histamine

histamine

inflammatory chemical that acts as vasodilator and attracts WBCs to inflamed sites

Agranulocytes

lack visible cytoplasmic granules, both have spherical or kidney shaped nuclei

life span of arganulocytes

hours to years

two types of agranulocytes

lymphocytes and monocytes

lymphocytes

found in lymph tissue

what are the two types of lymphocytes

T cells and B cells

T lymphocytes (T cells)

act against virus- infected cells and tumor cells

B lymphocytes (B cells)

give rise to plasma cells which produce antibodies

monocytes

abundant pale blue cytoplasm, dark purple-staining, U- or kidney-shaped nuclei, leave circulation, enter tissues, and differentiate into macrophages, actively phagocytic, activate lymphocytes to mount an immune response

leukocyte production

all originate from hemocytoblast stem cell that branches into two pathways

lymphoid stem cells

produces lymphocytes

myeloid stem cells

produce all other elements

leukemia

immature, nonfunctional WBCs flood bloodstream, cancerous cells fill red bone marrow, crowding out other cell lines, leads to anemia and bleeding

mononucleosis

highly contagious viral disease, usually seen in young adults, caused by Epstein-Barr virus, results in high numbers of typical aranuocytes,

platelets

cytoplasmic fragments of megakaryocytic

function of platelets

form temporary platelet plug that helps seal breaks in blood vessels

Platelets life span

age quickly and degenerate in about 10 days

hemostasis

processes that stop bleeding

first step of clot formation

vascular spasm- smooth muscle contracts causing vasoconstriction

second step of clot formation

platelet plug formation- injury to lining of vessel exposes collagen fibers; platelets adhere, platelets release chemicals that make nearby platelets sticky; plates plug forms

third step of clot formation

coagulation- fibrin forms a mesh that traps red blood cells and platelets forming the clot

thromboembolic disorders

undesirable clot formation

thrombus

clot that develops and persists in unbroken blood vessel, may block circulation, leading to tissue death

embolus

thrombus freely floating in bloodstream