Module 7 - Blood and Blood Vessels Flashcards
Formed elements
-erythrocytes, leukocytes, platelets
- arise from stem cells of the red bone marrow
Plasma
-extracellular matrix that makes blood unique among connective tissues because it is fluid.
-yellow colored liquid
-Water, protein, nutrients
Erythrocytes
-red blood cells, transport oxygen, and some carbon dioxide
-99% of blood cells
-Not true cells, no nucleus or organelles
-only one type
-short life span, but longer than leukocytes
Blood type
classified according to the presence, or absence, of certain antigens; four major blood types are A, AB, B, and O
Surface antigens (A & B)
the presence or absence of surface antigens A and B on red blood cells, known as the ABO blood group, is the primary factor that determines donor compatibility in blood transfusions
Antibodies
A protein that acts against a specific antigen
Rh Factor
Refers to the presence or absence of the Rh antigen on red blood cells.
Leukocytes
-white blood cell
-protect the body against invading microorganisms and body cells with mutated DNA, and they clean up debris.
-larger than erythrocytes and are the only formed elements that are complete cells, possessing a nucleus and organelles
-many types
-short lifespan
Granulocytes
-contain abundant granules within the cytoplasm. They include neutrophils, eosinophils, and basophils.
Neutrophil
-most common; comprise 50–70 percent of the total leukocyte count
-rapid responders to the site of infection and are efficient phagocytes with a preference for bacteria
Eosinophil
-represent 2–4 percent of the total leukocyte count
-Attack inflammation (include antihistamine molecules, which counteract the activities of histamines, inflammatory chemicals produced by basophils)
-Parasites (contain molecules toxic to parasitic worms)
Allergic reactions
-Phagocytic (the process by which cells surround and digest certain particles)
-High counts of eosinophils are typical of patients experiencing allergies, parasitic worm infestations, and some autoimmune diseases
Basophil
-least common; typically comprising less than one percent of the total leukocyte count
-slightly smaller than neutrophils and eosinophils
-basophils intensify the inflammatory response
-granules of basophils release histamines, which contribute to inflammation, and heparin, which opposes blood clotting
-High counts of basophils are associated with allergies, parasitic infections, and hypothyroidism
Agranulocytes
include monocytes, which mature into macrophages that are phagocytic, and lymphocytes, which arise from the lymphoid stem cell line.
Lymphocytes
-only formed element of blood that arises from lymphoid stem cells
-the second most common type of leukocyte, accounting for about 20–30 percent of all leukocytes, and are essential for the immune response
-three major groups of lymphocytes include natural killer cells, B cells, and T cells
Monocytes
-originate from myeloid stem cells
-normally represent 2–8 percent of the total leukocyte count
-able to migrate into tissues and transform into a macrophage.
Hematopoiesis
-Production of blood cells
-Blood cells produced in the liver and spleen before birth
-Red bone marrow produces blood cells beginning ~ 5 months and is the primary site of hematopoiesis after birth
-Liver produces >90% of plasma proteins
Anemia
When the number of red blood cells or hemoglobin is deficient; decreased hemacrit
Platelets
-aka thrombocytes
-Smallest circulating formed elements – cell fragments
-Involved in clotting
-Lifespan of approximately 8 -10 days
Vessel Wall Layers
tunica intima, tunica media, tunica externa
Tunica intima
-the innermost layer of a blood vessel
-It is composed of a lining of endothelium and an underlying layer of connective tissue.
Endothelium
Lining the tunica intima is the specialized simple squamous epithelium called the endothelium
Tunica media
-layer is primarily composed of concentric layers of smooth muscle tissue
-The middle layer of a blood vessel
-The layer that is responsible for vasoconstriction and vasodilation.
Tunica externa
-its fibers blend into the surrounding tissue, anchoring and stabilizing the blood vessel.
-The outermost layer of a blood vessel.
Vasa vasorum
small blood vessels within the walls of larger arteries and veins; supply blood to outer part of the larger vessels
Arteries
a blood vessel that carries blood away from the heart, where it branches into ever-smaller vessels
Elastic arteries
closer to the heart; allow stretch as blood is pumped into them and recoil when ventricles relax
Muscular arteries
distal to elastic arteries; deliver blood to body organs
Distributing arteries
Carry blood to specific organs and tissues; also called muscular arteries
Arterioles
vessels that are the smallest arteries
Vasoconstriction
the constriction of blood vessels, which increases blood pressure.
Vasodilation
widening of blood vessels
Capillaries
tiny vessels that arterioles branch into where nutrients and wastes are exchanged, and then combine with other vessels that exit capillaries to form venules
Continuous capillaries
-most common and found in almost all vascularized tissues
-characterized by a complete endothelial lining with tight junctions between endothelial cells
-complete basement membrane
Fenestrated capillaries
-has pores (or fenestrations) in addition to tight junctions in the endothelial lining
-These make the capillary permeable to larger molecules.
-common in the small intestine, the primary site of nutrient absorption, and the kidneys, which filter the blood
Sinusoids (sinusoidal) capillaries
-least common, flattened, and they have extensive intercellular gaps and incomplete basement membranes, in addition to intercellular clefts and fenestrations.
-large openings allow for the passage of the largest molecules, including plasma proteins and even cells
-blood flow very slow
Capillary bed
-a network of capillaries in a tissue or organ
-fed by an arteriole
Metarteriole
-a type of vessel that has structural characteristics of both an arteriole and a capillary
-Each metarteriole arises from a terminal arteriole and branches to supply blood to a capillary bed
Thoroughfare channel
metarteriole that continues through capillary bed to venule
Veins
Blood vessels that carry blood back to the heart; thin walls with large
lumens. Generally appear flat
Venules
small blood vessels that carry blood to a vein
Valves
promote the unidirectional flow of blood toward the heart and prevent backflow toward the capillaries caused by the inherent low blood pressure in veins as well as the pull of gravity
Collateral circulation
Alternative pathways for delivering blood to a region of the body; critical with blockage of a blood vessel
Anastomosis
joining of two ducts, vessels, or bowel segments to allow flow from one to another
Arteriovenous anastomoses
Regulate blood flow around capillary beds, connecting arteries directly
with veins
Arterio-arterial anastomoses
Provide collateral circulation to many organs and body regions
Rh blood group
classified according to the presence or absence of a second erythrocyte antigen identified as Rh
Polycythemia
A disorder characterized by an abnormal increase in the number of red blood cells in the blood
What is hematocrit?
the ratio of the volume of red blood cells to the total volume of blood
What is the buffy coat?
white blood cells and platelets
What is the normal ratio of plasma, buffy coat, and hemacrit in blood?
55:1:44
If you were looking at cross-sections of two blood vessels of relatively the same diameter, what features could you use to distinguish arteries from veins?
The artery wall is thicker with more smooth muscle, but the lumen is narrower.
Lumen
-a hollow passageway through which blood flows
-Arteries have smaller lumens than veins, a characteristic that helps to maintain the pressure of blood moving through the system
Which of the following is true regarding red blood cells?
1. The hematocrit is a good approximation of red blood cells in the blood because red blood cells make up the majority of the formed elements.
2. The shape of red blood cells allows for greater surface area for diffusion of gasses.
3. Red blood cells play a critical role in controlling infections in the the body.
4. Red blood cells are spherical in shape.
5. Red blood cells transport oxygen and carbon dioxide in the bloodstream.
6. The shape of red blood cells causes them to be rigid and fragile, sometimes causing problems when they travel through capillaries.
1, 2, 5
Muscular arteries:
have a thick media with a large amount of smooth muscle fiber within them
Which of the following is true of an artery?
1. The adventitia is frequently absent.
2. The histological structure permits a two-way exchange of substances between the blood and body cells.
3. The vessel walls are relatively thin.
4. Blood flow is the slowest of all classes of vessels.
5. The lumen is relatively smaller than that of a corresponding vein.
5
Which vessels collect blood from capillaries?
Venules
In organs that function to filter the blood and remove contaminants, which of the following types of capillaries allow the greatest access to blood to perform this task?
1. fenestrated capillaries
2. continuous capillaries
3. arterioles
4. sinusoid capillaries
- sinusoid capillaries
What is the function of the valves within the veins?
to prevent the backflow of blood away from the heart
Summarize the histological organization of blood vessels’ walls?
The wall is composed of an outer layer of fibrous connective tissue, a middle layer with sheets of smooth muscle and an elastic framework, and a thin, smooth epithelial inner layer bound to areolar tissue.
What is the correct comparison between the walls of arteries and veins?
1. Veins have thicker walls than arteries have
2. Veins have endothelial linings that appear pleated, but arteries do not.
3. Arteries have more smooth muscle and elastic fibers than veins have.
4. The media layer of veins is thicker because of increased layers of smooth muscle cells.
- Arteries have more smooth muscle and elastic fibers than veins have.
Which of the following is best adapted to dealing with pulses of high blood pressure?
elastic arteries
Which type of white blood cell is most common?
neutrophils
Which of the following statements are true?
1. A patient with type O- blood is known as the universal donor
2. A patient who is Rh+ can receive blood from a patient who is Rh+ or Rh-
3. A patient with type AB+ blood is known as the universal recipient
4. A patient with type A blood is compatible to receive a transfusion from type B
5. A patient with type AB blood is compatible to receive a transfusion from type A or B
6. A patient with type O blood is compatible to receive a transfusion from type AB
7. A patient with type B blood is compatible to receive a transfusion from type A
1, 2, 3, 5
The primary site of hematopoiesis in an adult is:
the red bone marrow
