Blood Flashcards
Blood transports what through blood vessels?
- Nutrients
- Wastes
- Hormones
- Body Heat
what kind of tissue is blood?
The only fluid tissue, a type of connective tissue
what are the components of blood?
- Formed elements (living cells)
- Plasma (nonliving fluid matrix)
What happens to plasma when blood is separated?
the plasma rises to the top (55% of blood)
What happens to Erythrocytes/red blood cells when blood is separated? what is the percentage called?
they sink to the bottom (45% of blood, a percentage known as the Hematocrit)
what does the buffy coat of blood contain?
Leukocytes, or white blood cells, and platelets (Less than 1% of blood)
where is the buffy coat?
it is a thin, whitish layer btwn the Erythrocytes and Plasma
What are the characteristics of blood?
- Sticky, opaque fluid
- Heavier & thicker than water
- Color range
- Oxygen-rich blood is scarlet red
- Oxygen-poor blood is dull red or purple
- metalic, salty taste
- Blood pH is slightly alkaline, btwn 7.35 and 7.45
- Blood temperature is slightly higher than body temp at 38C or 100.4F
what is blood volume?
- About 5-6 L, or about 6 quarts of blood are found in a healthy adult
What percentage of blood makes up body weight
8%
What percentage of plasma is water? what colour is plasma?
90%, Straw-colored fluid
which dissolved substances can be found in plasma?
- Nutrients
- Salts (electrolytes)
- Respiratory gases
- Hormones
- Plasma proteins
- Waste products
what are Erythrocytes?
Red blood cells (RBCs)
what are Leukocytes?
White blood cells (WBCs)
what are Platelets?
Cell fragments
What is the main function of RBCs?
to carry oxygen
how do RBCs differ from other blood cells?
- Anucleate (no nucleus)
- Contain few organelles; lack mitochondria
- Make ATP by anaerobic means
- Essentially “bags” of hemoglobin (Hb)
- Shaped like biconcave discs
what is the normal count of RBCs?
5 million RBCs per cubic millimeter of blood
how many oxygen molecules can hemoglobin bind to?
4
how many hemoglobin molecules does each erythrocyte have?
250 million
normal blood contains how many grams of hemoglobin?
12 - 18 g of hemoglobin per 100 ml of blood
anemia is a decrease in the oxygen-carrying ability of the blood due to?
- Lower-than-normal number of RBCs
- Abnormal or deficient hemoglobin content in the RBCs
sickle cell anemia (SCA) results from?
Abnormally shaped hemoglobin
what is polycythemia?
Disorder resulting from excessive or abnormal increase of RBCs due to:
- Bone marrow cancer (polycythemia vera)
- Life at higher altitudes (secondary polycythemia)
An increase in RBCs does what to blood flow and blood viscosity?
- Slows blood flow
- Increases blood viscosity
Leukocytes (white blood cells/WBCs) are?
- Crucial in body’s defence against disease
- Complete cells with nucleus and organelles
- Able to move into and out of blood vessels (diapedesis)
- Respond to chemicals released by damaged tissues (known as positive chemotaxis)
- Move by amoeboid motion by forming cytoplasmic extensions to help them move
How many WBCs in blood?
4,800 to 10,800 WBCs per mm3 of blood
Homeostatic imbalance of WBCs: Leukocytosis
Normal response to an infection but excessive production of abnormal WBCs during infectious mononucleosis or leukemia is pathological
Homeostatic imbalance of WBCs: Leukopenia
- Abnormally low WBC count
- Commonly caused by certain drugs, such as corticosteroids and anticancer agents
Homeostatic imbalance of WBCs: Leukemia
- Bone marrow becomes cancerous
- Numerous immature WBC are produced
Platelets are?
- Fragments of megakaryocytes (multinucleate cells)
- Needed for the clotting process
How many platelets in blood?
Normal platelet count is 300,000 platelets per mm3 of blood
Hematopoiesis (Blood Cell Formation) IMPORTANT
- Hematopoiesis is the process of blood cell formation
- Occurs in red bone marrow (myeloid tissue)
where are all blood cells derived from?
A common stem cell (hemocytoblast)
Hemocytoblasts form 2 types of descendants
- Lymphoid stem cell, which produces lymphocytes
- Myeloid stem cell, which can produce all other formed elements
Formation of Red Blood Cells IMPORTANT
- Since RBCs are anucleate, they are unable to divide, grow, or synthesize proteins
- RBCs wear out in 100 to 120 days
- When worn out, RBCs are eliminated by phagocytes in the spleen or liver
Lost RBCs are replaced by?
Division of hemocytoblasts in the red bone marrow
Reticulocytes are?
Young RBCs which enter the blood to become oxygen-transporting erythrocytes
Rate of RBC production is controlled by a hormone called?
Erythropoietin
Kidneys produce most erythropoietin as?
A response to reduced oxygen levels in the blood
Homeostasis is maintained by?
Negative feedback from blood oxygen levels
Hemostasis is the process of?
Stopping the bleeding that results from a break in a blood vessel
Hemostasis involves three phases
- Vascular spasms
- Platelet plug formation
- Coagulation (blood clotting)
Hemostasis, Step 1: Vascular spasms
- Immediate response to blood vessel injury
- Vasoconstriction causes blood vessel to spasm
– Spasms narrow the blood vessel, decreasing blood
loss
Hemostasis, Step 2: Platelet plug formation
– Collagen fibers are exposed by a break in a blood
vessel
– Platelets become “sticky” and cling to fibers
– Anchored platelets release chemicals to attract more
platelets
– Platelets pile up to form a platelet plug
Hemostasis, Step 3: Coagulation
– Injured tissues release tissue factor (TF)
– PF3 (a phospholipid) interacts with TF, blood protein
clotting factors, and calcium ions to trigger a clotting
cascade
– Prothrombin activator converts prothrombin to
thrombin (an enzyme)
– Thrombin joins fibrinogen proteins into hairlike
molecules of insoluble fibrin
– Fibrin forms a meshwork (the basis for a clot)
– Within the hour, serum is squeezed from the clot as it
retracts to pull edges of the blood vessel together
▪Serum is plasma minus clotting proteins
In hemostasis blood usually clots within?
3 to 6 min
In hemostasis the clot_______?
remains as endothelium regenerates
In hemostasis the clot is broken down after?
Tissue repair
What is a Thrombus?
- A clot that develops and persists in an unbroken blood vessel
- Can be deadly in areas such as the lungs
What is an Embolus?
- A thrombus that breaks away and freely in the bloodstream
- Can later clog vessels in critical areas such as the brain
Bleeding disorders: what is thrombocytopenia?
▪Insufficient number of circulating platelets
▪Arises from any condition that suppresses the
bone marrow
▪Even normal movements can cause bleeding
from small blood vessels that require platelets for
clotting
▪Evidenced by petechiae (small purplish blotches
on the skin)
Bleeding disorders: what is hemophilia?
▪Hereditary bleeding disorder
▪Normal clotting factors are missing
▪Minor tissue damage can cause life-threatening
prolonged bleeding
What are 2 serious consequences large losses of blood have?
– Loss of 15 to 30 percent causes pallor and weakness
– Loss of over 30 percent causes shock, which can be
fatal
Blood transfusions are given for?
substantial blood loss, to treat severe anemia, or for thrombocytopenia
Blood contains genetically determined proteins known as?
Antigens
Antigens are?
Substances that the body recognizes as foreign and that the immune system may attack
– Most antigens are foreign proteins
– We tolerate our own “self” antigens
Antibodies are?
The “recognizers” that bind foreign antigens
Blood is “typed” by?
Using antibodies that will cause blood certain proteins to clump (agglutination) and lyse
Blood types are based on the presence or absence of 2 antigens which are?
- Type A
- Type B
- Presence of both antigens A & B is?
- Presence of antigen A is?
- Presence of antigen B is?
- Lack of both antigens A & B is?
- Type AB
- Type A
- Type B
- Type O
-Type AB can receive?
- Type AB is the?
- Can receive A, B, AB & O blood
- Is the “universal recipient”
Type B can receive?
B & O blood
Type A can receive?
A & O blood
- Type O can receive?
- Type O is the?
- O blood
- “Universal donor”
Rh blood group is named for? IMPORTANT
– Named for one of the eight Rh antigens (agglutinogen
D) identified in Rhesus monkeys
– Most Americans are +
Rh (Rh-positive), meaning they
carry the Rh antigen
Anti-Rh antibodies are not?
not automatically formed in the
blood of Rh-negative individuals (unlike the antibodies
of the ABO system)
