Download Blood By - Holly H. Nash

Blood
By: Dr. Holly Nash-Rule
Functions of blood
• Distribution/transport - nutrients, wastes,
gases, etc.
• Communication, i.e., hormones
• Prevention of fluid loss – hemostasis, osmosis
• Maintenance of pH
• Disease/ infection fighting
• Heating/Cooling
Blood Circulation
• Powered by the pumping action of the heart
• Functions of blood
• Carries respiratory gases, nutrients, and
hormones
• Helps body regulate temperature
• Blood volume
• Males: 5–6 liters
• Females: 4–5 liters
Composition of Blood
• Contains cellular and liquid components
• A specialized connective tissue
• Blood cells—formed elements
• Plasma—fluid portion and fibrinogen
• Hematocrit—measure of % RBC
• Males: 47% ± 5%
• Females: 42% ± 5%
Major Components of Whole Blood
Plasma
55% of whole blood
Least dense component
Buffy coat
Leukocytes and platelets
<1% of whole blood
1 Withdraw
blood and place
in tube.
2 Centrifuge the
blood sample.
Erythrocytes
45% of whole blood
Most dense component
Formed
elements
Blood Plasma
• Straw-colored, sticky fluid portion of blood
• Approximately 90% water
• Contains over 100 kinds of molecules
• Ions—Na+ and Cl–
• Nutrients—Sugars, amino acids, lipids,
wastes, and proteins
• Three main proteins
• Albumin, globulins, and fibrinogen
Formed Elements
• Blood cells
• Erythrocytes, leukocytes, and platelets
• Staining of blood cells
• Acidic dye—eosin; stains pink
• Basic dye—methylene blue; stains blue and
purple
Platelets
Neutrophils
Erythrocytes Monocyte
Lymphocyte
Photomicrograph of a human blood smear
Erythrocytes
• Oxygen-transporting cells—7.5 µm in
diameter (diameter of capillary 8—10mm)
• Most numerous of the formed elements
• Females: 4.3–5.2 million cells/cubic
millimeter
• Males: 5.2–5.8 million cells/cubic
millimeter
• Have no organelles or nuclei
Erythrocytes
• Are packed with oxygen-carrying
hemoglobin
• Hemoglobin molecule bears four oxygen
molecules
• Each O2 molecule bears an iron molecule
• Results in the oxidation of iron atoms of
hemoglobin molecules
• Gives blood its red color
Erythrocytes
• Pick up O2 at lung capillaries
• Release O2 across other tissue capillaries
• Structural characteristics contribute to
respiratory function
• Biconcave shape  30% more surface
area
• 97% hemoglobin
• Lack mitochondria
• Do not consume O2 they pick up
Erythrocyte
Leukocytes—White Blood Cells (WBCs)
• 4,800–11,000/cubic millimeter
• Protect the body from infectious
microorganisms
• Function outside the bloodstream in loose
connective tissue
• Circulating leukocytes leave the capillaries
• Originate in bone marrow
Leukocytes—White Blood Cells (WBCs)
• Two types of leukocytes
• Granulocytes
• Agranulocytes
• Girls Never Eat Bananas
• Around Long-armed Monkeys
Relative Percentages of the Different
Types of Leukocytes
Differential
WBC count
(All total 4,800–
10,800/l)
Formed
elements
Platelets
Granulocytes
Leukocytes
Neutrophils (50–70%)
Eosinophils (2–4%)
Basophils (0.5–1%)
Erythrocytes
Agranulocytes
Lymphocytes (25–45%)
Monocytes (3–8%)
Granulocytes
• Neutrophils—most
numerous WBC
• Phagocytize and
destroy bacteria
• Nucleus—has two
to six lobes
• Granules pick up
acidic and basic
stains
Granulocytes
• Eosinophils—compose
1–4% of all WBCs
• Play roles in
• Ending allergic
reactions,
parasitic
infections
• Granules pick up
mostly acidic stain
Granulocytes
• Basophils—about 0.5% of
all leukocytes
• Nucleus—usually two
lobes
• Function in inflammation
mediation
• Granules secrete
histamines
• Granules pick up
mostly basic stain
Agranulocytes
• Lymphocytes—compose 20–45%
of WBCs
• The most important cells of the
immune system
• Nucleus—stains dark purple
• Effective in fighting infectious
organisms
• Act against a specific foreign
molecule (antigen)
Agranulocytes
• Two main classes of lymphocyte
• T cells—attack foreign cells directly
• B cells—multiply to become plasma cells
• Secrete antibodies
Agranulocytes
• Monocytes—compose
4–8% of WBCs
• The largest
leukocytes
• Nucleus—kidney
shaped
• Transform into
macrophages
• Phagocytic cells
Platelets
• Cell fragments
• Break off from megakaryocytes
• Function in clotting of blood
Blood Cell Formation
• Hematopoiesis—process by which blood
cells are formed in red marrow
• 100 billion new blood cells formed each day
Bone Marrow as the Site of Hematopoiesis
• Bone marrow—located within all bones
• Red marrow—actively generates new blood
cells
• Contains immature erythrocytes
• In adults, red marrow is located
• Between trabeculae of spongy bone of
axial skeleton
• Appendicular girdles
• Proximal epiphyses of humerus and
femur
Bone Marrow as the Site of
Hematopoiesis
• Yellow marrow—dormant
• Contains many fat cells
• Located in the long bones of adults
Cell Lines in Blood Cell Formation
• All blood cells originate in bone marrow
• All originate from one cell type
• Blood stem cell (pluripotential
hematopoeitic stem cell)
• Lymphoid stem cells
• Give rise to lymphocytes
• Myeloid stem cells
• Give rise to all other blood cells
Proerythroblasts
Megakaryoblasts
Monoblasts
Myeloblasts
27
The End