Module 11: The Cardiovascular System Flashcards
How is blood a transport medium?
It takes oxygen from the lungs to tissues, takes carbon dioxide from the tissues to the lungs, transports nutrients from the small intestine to the liver and body cells, transports wastes from the tissues to the kidneys, and hormones from the endocrine glands to the cells throughout the body.
How is blood a regulatory tissue?
It regulates fluid volume by moving fluid from the intestines around the body so that all tissues receive the fluid they require. It also equalizes temperature differences and regulates the pH of the tissues.
How does the body regulate its temperature?
When the body is too warm, blood vessels near the skin constrict, drawing the blood away from the surface to the deeper, warmer parts of the body. When the body is too cold, those vessels open up and allow the blood to return to the surface to warm the skin again.
How is blood a protective tissue?
It protects against fluid loss through hemostasis. It also protects against infection with white blood cells.
Hemostasis
The mechanism within the blood that stops bleeding after a cut.
Viscosity
The resistance to flow and alteration of shape due to cohesion.
What gives blood its property of viscosity?
Red blood cells have a slight cohesion that causes them to resist flowing to a small extent.
What gives blood its density? (It’s more dense than water)
RBCs contain iron, a very dense substance.
What is the range of the blood’s normal pH, and what keeps it there?
7.35-7.45. The blood is designed with a buffering system to maintain the pH.
What two basic parts can blood be split into?
Plasma and formed elements.
Plasma
The fluid portion of the blood which is mostly water; about 55% by volume.
Formed elements of blood
The red blood cells, white blood cells, and cell fragments called platelets; about 45% by volume.
Describe the makeup of blood plasma.
90% water, 7% proteins, and 3% ions, nutrients, wastes, gases, and regulatory chemicals.
What are the three basic types of proteins in blood plasma?
Albumin, globulins, and fibrinogen.
Albumin
A small protein synthesized by the liver that regulates the movement of water between tissues and the blood by the process of osmosis. It makes up more than half the proteins in the plasma.
Globulins
Some act as carrier proteins while others, called gamma globulins, are antibodies responsible for fighting off infections. The globulins make up about 1/3 of the proteins in the plasma.
Fibrinogen
An inactive protein that plays a critical role when injury occurs. It can be activated to form a blood clot if bleeding occurs.
Describe the composition of the formed elements of blood.
95% erythrocytes and 5% leukocytes and platelets.
Erythrocytes
Red blood cells that carry the O2 in blood.
Why does O2 need a carrier in the blood?
Oxygen is nonpolar, so it does not mix well with water. Therefore, it must be transported on RBCs using a protein complex called hemoglobin.
Leukocytes
White blood cells that perform defensive functions in blood.
Thrombocytes
Fragments of white blood cells called megakaryocytes, which are found in the bone marrow. If activated, thrombocytes function in preventing blood loss after an injury to a blood vessel.
Describe the shape of erythrocytes and why that shape is effective to its purpose.
Erythrocytes are biconcave disks, and the edge of the cell is thicker than the center. This shape exposes more of the cells’ surface than a sphere, allowing gases such as oxygen and carbon dioxide to diffuse through the surface more efficiently. In addition, the cell can bend and deform around the thin center, making it easier to get through thin blood vessels.
Describe the composition of hemoglobin.
Hemoglobin is composed of four protein chains (called globins), each folded into a particular shape. The middle of each globin holds a flat molecule called heme. An iron atom (Fe) is bound in the middle of each heme.
What are some differences between erythrocytes and other cells?
Erythrocytes contain hemoglobin, are anucleate, and cannot repair themselves. Normal cells do not contain hemoglobin, have a nucleus, and can repair themselves.
How do erythrocytes make energy?
They have limited cellular machinery (no nucleus), so they generate small amounts of ATP through glycolysis, which does not require oxygen.
Anemia
A lack of sufficient O2 carrying capacity by the blood.
What two conditions cause anemia?
A lack of normal RBCs or a lack of hemoglobin.
Hematocrit blood test
A test that determines the percentage of RBCs in the blood.
What percent of the blood is composed of RBCs in a healthy adult?
Males: 44-48%
Females: 38-45%
How much hemoglobin is in a healthy adult?
A healthy adult has 12-16 grams of hemoglobin per 100mL of blood.
What vitamins and minerals are needed to make erythrocytes?
Iron, the B vitamins (including vitamin B12), folic acid, vitamin C, vitamin E, and minerals such as copper, cobalt, manganese, and zinc.
What is the chemical reaction that creates the bicarbonate that CO2 is carried through the blood in?
CO2 + H2O (catalyzed by H2CO3, carbonic acid) = HCO3 + H+
How does the chemical reaction to form bicarbonate vary throughout the body?
Near the tissues, where CO2 is produced, the reaction favors the left to right direction, forming more bicarbonate. Near the lungs, where CO2 leaves the body, the reaction favors the right to left direction, reforming and releasing the CO2.
How do leukocytes (white blood cells) move?
They move with amoeboid movement. They push out an extension of themselves, called a pseudopod, and then flow into it. This allows them to squeeze through pores in the microscopic blood vessels and move into the tissues, a process called diapedesis.
Diapedesis
Passage of white blood cells through pores in blood vessel to get into the tissue spaces.
Chemotaxis
Attraction of cells to chemical stimuli.
What are the two classes of leukocytes?
Granulocytes and agranulocytes.
What are the three divisions of granulocyte?
Neutrophil, basophil, and eosinophil.
What are the two divisions of agranulocytes?
Lymphocyte and monocyte.
Describe the characteristics of a neutrophil.
Most common of the white blood cells, nucleus with several lobes, small granules, first responders to an infection, attracted to foreign invaders by chemotaxis, and capable of phagocytosis.
Phagocytosis
Literally, cell-eating. The process by which a cell engulfs and ingests a foreign or dead cell or cell part.
Pus
A mixture of dead or dying white blood cells, foreign cells such as bacteria, and fluid.
Describe the characteristics of a basophil.
The rarest of the granulocytes, two-lobed nucleus, large granules, and react to allergic reactions by releasing histamine and heparin.
What effect does histamine have?
It promotes inflammation, which stimulates the immune system.
What effect does heparin have?
It prevents the blood from clotting locally. If blood clots at the area of infection, the white blood cells, antibodies, and other immune factors can’t get through. Thus, heparin is necessary.
Describe the characteristics of eosinophils.
Uncommon, two-lobed nuclei, increase in number during allergic reactions, decrease inflammation, and increase in number during parasitic infections.
Describe the characteristics of a lymphocyte.
A little larger than erythrocytes (RBCs), smallest white blood cell, second most common type of white blood cell, dark-staining nucleus with a small rim of cytoplasm, produce antibodies, and provide other immune protection.