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blood
a liquid connective tissue consisting of cells surround by a liquid matrix (plasma)
what % of blood is plasma
55
what % of blood is RBCs
45
what is the buffy coat
white blood cells and platelets
spun tube of blood yields three layers:
erythrocytes, WBCs/platelets (buffy coat), plasma
hematocrit
percent of blood volume that is RBCs
normal hematocrit values in men
47% +/- 5 %
normal hematocrit values in women
42% +/- 5%
where is the buffy coat in a spun tube of blood
between RBCs and plasma
where is plasma in spun tube of blood
on top
where are erythrocytes in spun tube of blood
on bottom
centrifuge
machine that separates substances by whirling them
The cellular components (formed elements) of blood include
red blood cells, white blood cells, and platelets
the plasma portion of blood consists of
water, proteins, other solutes
blood transports
oxygen, carbon dioxide, nutrients, hormones, heat, and waste products
blood regulates
homeostasis of all body fluids, pH, body temperature, and water content of cells
blood protects against
excessive loss by clotting, and uses white blood cells to protect against infections
lymphocytes are able to live for how long
years
most blood cells besides lymphocytes live for how long
hours, days, or weeks
the number of RBCs and platelets remains steady or varies
stays steady
the number of WBCs remains steady or varies?
varies, dependent on invading pathogens and other foreign antigens.
hemopoiesis
the process of producing blood cells (hematopoiesis)
pluripotent stem cells differentiate into
different types of blood cells
what are colony-stimulated factors (CSFs)
secreted glycoproteins that bind to receptor proteins on the surfaces of hemopoietic stem cells, thereby activating intracellular signaling pathways that can cause the cells to proliferate and differentiate into a specific kind of blood cell
administration of exogenous CSFs stimulate
the stem cells in the bone marrow to produce more of the particular white blood cells.
Bone marrow transplants are performed to
replace cancerous red bone marrow with normal red bone marrow
Where do they take bone marrow out of a donor?
Iliac crest of the hip bone
What can be an alternative for bone marrow transplants?
Stem cells collected and frozen from an umbilical cord after birth, and may have advantages over bone marrow.
RBCs (erythrocytes) contain which protein
hemoglobin
function of hemoglobin
to carry oxygen to all cells, and some CO2 to the lungs
each hemoglobin molecule contains
An iron ion which allows each molecule to bind 4 oxygen molecules
do RBCs have a nucleus or organelles
no
shape of RBCs
biconcave discs
diameter of RBC
7.5 micrometers (larger than some capillaries)
spectrin
a plasma membrane protein provides flexibility in RBCs so they can change shape
Each hemoglobin molecule can transport
4 O2
each RBC contains ________ Hb molecules
250
O2 loading in lungs produces
oxyhemoglobin (ruby red)
O2 unloading in tissues produces
deoxyhemoglobin, reduced hemoglobin (dark red)
when CO2 loads in tissues, _______% of CO2 in blood binds to Hb, producing ___________
20%; carbaminohemoglobin
hemoglobin is involved in regulating
blood flow and pressure via the release of nitric oxide (NO)
nitric oxide causes
vasodilation
vasodilation improves what 2 things
blood flow and oxygen delivery
RBCs contain carbonic anhydrase, which catalyzes ______
the conversion of CO2 and water to carbonic acid
How long do RBC live?
120 days
dead cells are removed from the circulation by which 2 organs
spleen and liver
breakdown products from RBCs are
recycled and reused
jaundice (icterus)
a yellowish or greenish pigmentation of the skin and whites of the eyes due to high bilirubin levels. The feces may be pale and the urine dark
erythropoiesis (production of RBCs) begins in
red bone marrow
Erythropoietin
a hormone released by the kidneys in response to hypoxia (lowered oxygen concentration) stimulates differentiation of hematopoietic stem cells into erythrocytes
reticulocytes are
immature red blood cells
reticulocytes enter the circulation and mature in how many days
1-2
Some athletes abuse artificial EPO. This increases
hematocrit, which allows athlete to increase stamina and performance
Dangerous consequences of artificial EPO
- EPO can increase hematocrit from 45% up to even 65%, with dehydration concentrating blood even more
- Blood becomes like sludge and can cause clotting, stroke, or heart failure
Most erythrocyte disorders are classified as either _______ or _______
anemia or polycythemia
anemia occurs when
Blood has abnormally low O2
-carrying capacity that is too low to support normal metabolism
- Sign of problem rather than disease itself
symptoms of anemia
fatigue, pallor, dyspnea, and chills
Three groups based on cause: Blood loss, Not enough RBCs produced, Too many RBCs being destroyed
What are the three groups of anemia?
blood loss, low RBC production, high RBC destruction
sickle cell disease
is a genetic anemia (oxygen carrying capacity of the blood is reduced)
The red blood cells of individuals with this disease contain hemoglobin-S (Hb-S), which causes
red blood cells to bend into a sickle shape when it gives up oxygen to the interstitial fluid
iron-deficiency anemia can be caused by
hemorrhagic anemia, but also by low iron intake or impaired absorption
Iron deficiency anemia can be caused by hemorrhagic Amelia, but
Also by low iron intake or impaired absorption
Do WBC (leukocytes) contain nucleus and organelles
yes
do WBC contain hemoglobin
no
2 classifications of WBC
granular and agranular
description of granular leukocytes
containing vesicles that appear when the cells are stained
types of granular leukocytes
neutrophils, eosinophils, basophils
description of agranular leukocytes
contain no granules
types of agranular leukocytes
lymphocytes and monocytes
White blood cells may live for
several months or years
main function of WBCs
combat invading microbes
During an invasion, many white blood cells are able to ______________
leave the bloodstream and collect at sites of invasion
the process of WBCs leaving the bloodstream and collecting at sites of invasion is called
emigration (diapedesis)
In general, an elevation in the white blood count usually indicates an
infection or inflammation
A low white blood cell count may develop due to several causes. This WBC count will help to determine if a problem exists
differential white blood cell count
neutrophils
A type of white blood cell that engulfs invading microbes and contributes to the nonspecific defenses of the body against disease.
eosinophil
white blood cell containing granules that stain red; associated with allergic reactions
basophil
white blood cell containing granules that stain blue; associated with release of histamine and heparin
lymphocyte
mononuclear leukocyte that produces antibodies
monocyte
an agranulocytic leukocyte that performs phagocytosis to fight infection
overproduction of abnormal WBCs can result in conditions like: __________________ or ________________
leukemias and infectious mononucleosis
leukopenia
Abnormally low WBC count
-Can be drug induced, particularly by anticancer drugs or glucocorticoids
leukemias
Cancerous condition involving overproduction of abnormal WBCs
infectious mononucleosis
Highly contagious viral disease ("kissing disease")
-Usually seen in young adults. Caused by Epstein-Barr virus
largest WBC
monocyte
most numerous WBC
neutrophil
secretes histamine
basophils
produces antibodies
lymphocyte
megakaryocytes in red bone marrow splinter into
2000-3000 fragments to create the platelets that contain many vesicles but no nucleus
platelets are used to
clot the blood
Under the influence of the hormone thrombopoietin, hemopoietic stem cells
differentiate into platelets
platelets survive for only
5-9 days
Hemostasis is a sequence of responses that
stop bleeding
hemostasis involves which three phases
vascular spasm, platelet plug formation, blood clotting (coagulation)
platelet plug formation
When activated, platelets swell, become spiked and sticky, and release chemical messengers: ADP causes more platelets to stick and release their content Serotonin and thromboxane A2 enhance vascular spasm and platelet aggregation
-Positive feedback cycle: as more platelets stick, they release more chemicals, which cause more platelets to stick and release more chemicals
blood clotting can be activated in one of these two ways
extrinsic pathway, intrinsic pathway
the extrinsic and intrinsic pathways lead to the formation of ____________, and from there the common pathway continues
prothromibinase
Intrinsic pathway of coagulation
occurs because clotting factors are present within the blood. Triggered by negatively charged surfaces such as activated platelets, collagen, or even glass of a test tube
extrinsic pathway of coagulation
factors needed for clotting are located outside blood, Triggered by exposure to tissue factor (TF); also called factor
Phase 2: Pathway to thrombin
Prothrombin activator catalyzes transformation of prothrombin to active enzyme thrombin
