Objective 1 pt 1 Flashcards
the life-sustaining transport vehicle of the cardiovascular system
blood
what are the functions of blood?
transport
regulation
protection
what are the transport functions?
delivering 02 and nutrients to body cells
transporting metabolic wastes to lungs and kidneys for elimination
transporting hormones from endocrine organs to target organs
what are the regulation functions?
maintaining body temp by absorbing and distributing heat
maintaining normal pH using buffers
maintaining adequate fluid volume in circulatory system
what are the protection functions?
preventing blood loss
preventing infection
plasma proteins and platelets in blood initiate clot formation
preventing blood loss
agents of immunity are carried in blood
preventing infection
only fluid tissue in the body
type of connective tissue
sticky, opaque fluid with metallic taste
color varies with O2 content
pH 7.35-7.45
makes up 8% of body weight
Blood
nonliving fluid
plasma
living blood cells
formed elements
what are the formed elements
erythrocytes
leukocytes
platelets
percent of blood volume that is RBCs
hematocrit
thin, whiteish layer between RBCs and plasma layers
buffy coat layer
high O2 levels
scarlet red
low O2 levels
dark red
straw-colored sticky fluid
over 100 dissolved solutes
blood plasma
most abundant solutes by weight
remain in blood; not taken up by cells to be used a fuel
proteins produced mostly by liver
plasma proteins
makes up 60% of plasma proteins
functions as carrier of other molecules, as blood buffer, and contributes to plasma osmotic pressure
albumin
small cells that contribute to gas transport
biconcave disc shape
anucleate
no organelles
filled with hemoglobin for gas transport
contain plasma membrane protein spectrin
erythrocytes
provides flexibility to change shape to pass through capillaries
spectrin
what are the 3 features of erythrocytes that make for efficient gas transport?
biconcave shape offers huge surface area for gas exchange
hemoglobin makes up 97% of cell volume
RBCs have no mitochondria
binds reversibly with oxygen
hemoglobin
composed of four polypeptide chains
two alpha and two beta chains
globin
bonded to each globin chain
gives blood red color
each one central iron atom binds one oxygen
heme
produces oxyhemoglobin when O2 binds with iron
O2 loading in lungs to bring O2 to body tissues
produces deoxyhemoglobin, or reduced hemoglobin
O2 unloading in tissues
20% of CO2 in blood binds to globins amino acid rather than heme producing carbaminohemoglobin
CO2 loading in tissues
formation of all blood cells
hematopoiesis
stem cell that gives rise to all formed elements
hormones and growth factors push stem cell toward specific pathway of blood cell development
once cells are committed to a certain blood cell pathway, it cannot change
hematopoietic stem cells
what are the stages of erythropoiesis?
hematopoietic stem cell
myeloid stem cell
proerythroblast
basophilic erythroblasts
polychromatic erythroblasts
orthochromatic erythroblasts
reticulocytes
mature erythrocyte
process of formation of RBCs that takes about 15 days
erythropoiesis
transforms into myeloid stem cell
hematopoietic stem cell
transforms into proerythroblast
myeloid stem cell
divides many times, transforming into basophilic erythroblasts
proerythroblast
synthesize many ribosomes
basophilic erythroblasts
synthesize large amounts of red-hued hemoglobin
polychromatic erythroblasts
contain mostly hemoglobin, so appear just pink; eject most organelles; nucleaus degrades, causing concave shape
orthochromatic erythroblasts
still contain small amount of ribosomes, differentiation occurs in bloodstream
reticulocytes
in 2 days, ribosomes degrade, transforming into mature RBC
mature erythrocyte
too few RBCs lead to….
tissue hypoxia
too many RBCs increase…
blood viscosity
what does balance between RBC production a d destruction depend on?
hormonal controls
dietary requirements
hormone that stimulates formation of RBCs
always small amount of EPO in blood to maintain basal rate
mainly released by kidneys in response to hypoxia
erythropoietin (EPO)
what are the causes of hypoxia that lead to formation of EPO?
decreased RBC numbers due to hemorrhage or increased destruction of RBCs
insufficient hemoglobin per RBC
reduced availability of O2
what are the dietary requirements for erythropoiesis?
amino acids
lipids
carbohydrates
iron
vitamin B12
stored in cells as ferritin and hemosiderin
transported in blood bound to protein transferrin
free iron
what are the lifespan of erythrocytes
100-120 days
are the only formed element that are complete cells with nuclei and organelles
make up <1% of total blood volume
function in defense against disease
leukocytes
WBC count over 11,000 per ul
leukocytosis
what are the 2 major categories of leukocytes?
granulocytes
agranulocytes
what are the 3 types of granulocytes?
neutrophils, eosinophils, basophils
larger and shorter-life than RBCs
contain lobed nuclei
cytoplasmic granules stain specifically with Wright’s stain
granulocytes
most numerous WBCs
about twice the size of RBCs
granules stain with both acid and basic dyes
granules contain either hydrolytic enzymes or antimicrobial proteins
very phagocytic
referred to as “bacteria slayers”
kill microbes by process called respiratory burst
neutrophils
cell metabolizes oxygen to synthesizes potent oxidizing substances such as bleach or hydrogen peroxide
respiratory burst
account for 2-4% of all leukocytes
nucleus has 2 lobes connected by a broad band; resembles ear muffs
red-staining granules digestive enzymes
also play role in allergies and asthma as well as immune response modulators
eosinophils
rarest WBCs, accounting for only 0.5-1% of leukocytes
nucleus deep purple with one to two constrictions
large, purpleish black granules contain histamine
are functionally similar to mast cells
basophils
inflammatory chemical that acts as vasodilator and attracts WBCs to inflamed sites
histamine
lack visible cytoplasmic granules
agranulocytes
what are the two types of agranulocytes?
lymphocytes and monocytes
second most numerous WBC, accounts for 25%
lrg, dark purple, circular nuclei with thin rim of blue cytoplasm
mostly found in lymphoid tissue, but a few circulate in blood
crucial to immunity
lymphocytes
what are the two types of lymphocytes?
T lymphocytes
B lymphocytes
act against virus-infected cells and tumor cells
T lymphocytes
give rise to plasma cells, which produce antibodies
B lymphocytes
largest of all leukocytes
abundant pale blue cytoplasm
dark purple staining, U-or kidney-shaped nuclei
leave circulation, enter tissues, and differentiate into macrophages
activate lymphocytes to mount an immune response
monocytes
production of WBCs are stimulated by two types of chemical messengers from red bone marrow and mature WBCs
leukopoiesis
are numbered
interleukins
are named for WBC type they stimulate
colony-stimulating factors
what are the two pathways that a hemocytoblast stem cell can branch into?
lymphoid stem cells
myeloid stem cells
produces lymphocytes
lymphoid stem cells
produce all other elements
myeloid stem cells
what are the stages of production of a granulocyte?
myeloblasts
promyelocytes
myelocytes
band cells
mature granulocyte
arise from myeloid line stem cells
myeloblasts
accumulate lyosomes
promyelocytes
cells accumulate granules and cell division stops
myelocytes
nuclei form curved arc
band cells
nuclei become segmented before being released in blood
mature granulocyte
what is the production of a monocyte?
Monoblast —> promonocyte —> monocyte
share common precursor with neutrophils
can live for several months
what is the production of a lymphocyte?
T lymphocyte precursors give rise to immature T lymphocytes that mature in thymus
B lymphocyte precursors give rise to immature B lymphocytes that mature within bone marrow
