Transcript Blood - Liberty Hill High School

Blood
Physical Characteristics of Blood
• Color range
– Oxygen-rich blood is bright red
– Oxygen-poor blood is dull red
• pH must remain between 7.35–7.45
• Blood temperature is 100.4°F
• Blood volume = 5–6 L adult male
4-5 L adult female
• Blood is 8% of body weight.
What are the
functions of blood?
• Transports nutrients, wastes,
oxygen, and hormones.
• Defense against pathogens.
• Restriction of blood loss (clotting)
• Regulates electrolytes and pH in
interstitial fluid
• Distributes heat throughout body
Composition of Blood
• Formed Elements:
1. Erythrocytes (RBC)
2. Leukocytes (WBC)
3. Thrombocytes
(platelets)
• Plasma: 90% water and
dissolved substances
Erythrocytes or RBC
•
•
•
•
•
Biconcave shape
Flexible
Lack nuclei
Hemoglobin present
Function: To carry
oxygen (also
removes CO2)
• Diet needs: iron, folic
acid and vitamin B12
• “Erythro” means red
Get Body Smart – RBC’s
Erythrocytes under the
microscope
Hemoglobin
• Contains iron which O2 binds
with.
• Each hemoglobin contains 4
binding sites for oxygen.
• 250 million hemoglobin
molecules per RBC!
• Anemia is a decrease in the
oxygen-carrying ability of the
blood.
• Sickle cell anemia (SCA)
results from abnormally
shaped hemoglobin.
Erythropoiesis
• Definition: Formation of RBC’s.
• Location: Red bone marrow
• All blood cells are derived from a common
stem cell (hemocytoblast)
• Wear out in 100 to 120 days
• When worn out, RBCs are eliminated by
phagocytes in the spleen or liver.
• Rate of cell production controlled by the
hormone Erythropoietin (EPO).
Hematopoiesis: Development of blood cells from
hemocytoblasts (stem cells) in bone marrow.
Thrombocytes
or
“The Platelets”
Thrombocytes
• Made from Megakaryocyte
stem cells
• No nuclei, very tiny, and
granules present.
• Circulate freely, inactive
until vessel injury
• Function: “Hemostasis”
(stoppage of bleeding)
• Short life-span (5-9 days)
Hemostasis
(Click for animation)
• Three mechanisms:
1. Vascular spasm – smooth muscle
constricts blood vessel to prevent more
loss.
2. Platelet plug formation – platelets
adhere to exposed collagen fibers and
to each other to plug hole.
3. Blood clotting (coagulation) –
“molecular glue” that will result in a fibrin
mesh with the help of clotting factors
and procoagulants.
• Vitamin K needed to form clotting
factors.
• Normal clotting time = 3-6 minutes
A scanning electron micrograph of fibrin threads.
Platelet Problems
• Thrombus – abnormal blood clot formed
in an unbroken vessel.
Coronary thrombosis: blood clot
forming in a heart blood vessel
Cerebral thrombosis: blood clot forming
in a brain blood vessel
Deep Vein Thrombosis: blood clot
forming in lower extremities animation
• Embolus – traveling blood clot
Pulmonary embolism: clot that travels
and blocks vessel that supplies the
lungs.
• Atherosclerosis – accumulation of fat
deposits can initiate a thrombus to form.
Atherosclerosis
Animation
The Plasma
What is in it?
• Clear, straw-colored, liquid portion in which the
cells and platelets are suspended.
• Approximately 90% water
• Includes many dissolved substances
– Nutrients – glucose, amino acids, lipids
– Electrolytes – Na+, K+, Ca2+ etc.
– Respiratory gases - CO2, O2, N2
– Hormones
– Plasma proteins
– Waste products – urea, uric acid, excess items
Plasma Functions
• Transports nutrients, gases, and vitamins
• Helps regulate fluid and electrolyte balance
• Maintains favorable pH
Plasma proteins
• Most abundant of dissolved substances
(solutes) in plasma
• Most plasma proteins are made by liver
1. Albumins – regulate osmotic pressure
2. Globulins – antibodies & fat transport
3. Fibrinogen – blood clotting
4. Regulatory proteins – enzymes, clotting,
and hormone transport.
White Blood Cells (Leukocytes)
Leukocyte Special
Characteristics
• Diapedesis
– Reach infection site by slipping into and
out of blood vessels
• Ameboid motion
– Move through tissue spaces to reach
location
• Chemotaxis
– Respond to chemicals released by
damaged cells in order to locate damaged
area
Leukocytes
• Function is to protect against infection in various
ways: How???
– Phagocytize bacterial/dead cells in the body
– Produce proteins (antibodies) that destroy or disable
foreign particles
– Use chemicals to destroy pathogens or infected cells
• Cytokines and interleukins – chemicals released by
cells to activate WBC’s.
• Pus – solution of WBC’s, bacteria and damaged cells.
• “leuko” means white
Types of WBC’s
Granulocytes (cytoplasmic granules)
1.Neutrophils
2.Eosinophils
3.Basophils
Agranulocytes (no cytoplasmic granules)
1.Lymphocytes
2.Monocytes
Neutrophils
• Most common type
• Multi-lobed nucleus
• Phagocytic – will
chase down bacteria!
• Granules stain light
purple/blue
• Numbers increase
during bacterial &
fungal infections
Eosinophils
• Fairly rare, not that
common
• Bilobed nucleus
• Red cytoplasmic
granules.
• Involved in allergic
reactions and parasitic
infections…like
worms!
Basophils
• EXTREMELY RARE!
• Dark blue granules
• Bilobed nucleus present
but difficult to see
because of the dark
granules
• Involved in allergic
reactions as producers
of histamine and
heparin to increase
blood flow
Monocytes
• Largest leukocyte
• No granules
• Horse-shoe shaped
nucleus.
• Phagocytic
• Important in activating
lymphocytes for
specific immune
response
Lymphocytes
• Very abundant
• No granules
• Cytoplasm minimally
seen
• Rounded nucleus
almost size of entire cell
• Close in size to RBC
• Types: B or T
– B’s - Antibody
producing cells
– T’s – chemically kills
infected cells