CH 17
BLOOD
The Functions of Blood
• (1) Transport
medium that picks up
food and oxygen
• (2) Picks up wastes
for delivery to
excretory organs
• (3) Transports
hormones, enzymes,
buffers, and other
biochemical
substances
Fluid Portion= 55%
Called plasma and composed of
water, proteins, and solutes.
Formed elements= 45%
• Red blood cells (RBC) aka
erythrocytes
• White blood cells (WBC) aka
leukocytes
• Platelets aka thrombocytes
Red Blood Cells
(Erythrocytes)
• No nucleus
• Primary component is hemoglobin which
gives the red color and accounts for one
third of cell volume
Function of RBCs
• Transport of oxygen and carbon dioxide
depends on the hemoglobin
Formation of Red Blood Cells
• Called Erythropoiesis.
• Every minute you create 200 BILLION to replace
an equal number destroyed at that brief time!
• Formation begins in bone marrow from
hematopoietic stem cells
• Animation:
Negative Feedback:
http://health.howstuffworks.com/adam-200028.htm
-If oxygen levels decrease (like at high altitude),
kidneys release hormone erythropoietin, and this
stimulates RBC production in red bone marrow.
Red Blood Cell Destruction
• Life span of RBCs is about 105 to 120
days. As they age, they break apart in the
capillaries
• Macrophage cells phagocytose the cells,
releasing amino acids, iron, and bilirubin
• ANIMATION:
http://highered.mcgraw-
hill.com/sites/0072495855/student_view0/chapter21/animation__hemoglobin_breakdown.html
White Blood Cells (Leukocytes)
• Classified by
presence or absence
of granules
• Granulocytes - have
large granules
• Agranulocytes – do
not have cytoplasmic
granules
Granulocytes
• Neutrophils – small and numerous
granules and 65% of total WBC count
• Eosinophils – large numberous granules,
2%-5% of WBCs
• Basophils – large but sparse granules that
only .5% to 1% of WBCs
Agranulocytes
• Lymphocytes – smallest of leukocytes,
25% for WBCs
• Monocytes – largest of leukocytes
Formation of WBC
• Granulocytes originate in bone marrow.
• Agranulocytes originate in lymphatic tissue
Platelets
• Small, pale bodies that appear as irregular
spindles or oval disks
• Physical properties include agglutination,
adhesiveness, and aggregation
Function and Formation of
Platelets
• Play important role in hemostasis
(stoppage of blood flow) and blood clotting
• Form platelet plugs to stop flow of blood
into tissues when damage occurs
• Platelets formed in bone marrow, lungs,
and spleen by fragmentation of large cells
called megakaryocytes.
• Life span of 7 days
ABO Blood Groups
U.S. Blood-type Distribution
O+
38 percent of population
A+
34 percent of population
B+
9 percent of population
O7 percent of population
A6 percent of population
AB+
3 percent of population
B2 percent of population
AB1 percent of population
Writing Blood Types
• Blood types are codominant genetic traits
Blood Type
Homozygous Genotype
Heterozygous
Genotype
Type A
I AIA
IAi
Type B
I BIB
IBi
Type AB
-
IAIB
Type O
ii
-
Example of a Blood Type Problem
• Mother is type A (remember this could be
homozygous or heterozygous!)
• Father is type B (remember this could be
homozygous or heterozygous!)
• What blood types could their children be?
Rh System
• Rh-positive – Rh antigen is
present
• Rh- negative – Rh anitgen
not present
• Blood does not normally
contain anti-Rh antibodies,
EXCEPT when an Rhnegative person is given a
transfusion of Rh-positive
blood or…a Rh-negative
mother with a Rh-positive
fetus (see next slide)
Erthryoblastosis fetalis
Erythroblastosis
fetalis occurs
when a mother’s
Rh antibodies
react with a
fetus’s Rh
positive cells.
Animation: http://www.marchofdimes.com/figure2_RhDisease.swf.swf
RhoGAM
• All Rh-negative mothers who could carry a
Rh positive baby should be treated with
RhoGAM
• RhoGAM stops the mother’s body from
forming Rh antibodies so it prevents
hurting the fetus of a Rh baby.
Blood Clotting
• Four Components that help
clotting: are…Prothrombin,
thrombin, fibrinogen, fibrin
• Extrinsic – chemicals
released from damaged tissue
• Intrinsic – chemicals present
in the blood
Disorder Animations
•
•
•
•
Sickle Cell Anemia:
Leukemia
Thrombosis
Embolism (a thrombus that has moved).
• Find the description of these diseases. Type them up in
your own words (short definitions all on one page).
Bring them in to receive 2pts for each correct definition
on your test. You must be able to explain them to me at
any moment that I ask you or you will lose credit. This
must be your own work. No two should be exactly the
same
Disorders Continued
• Anemia
Blood cannot carry
sufficient oxygen to
inadequete number of
RBCs or hemoglobin
• Hemophilia (sex linked
recessive- like
colorblindness!) –
blood clotting disorder