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.
Antibodies
Proteins that specifically protect against foreign invaders.
Describe the characteristics of monocytes.
Biggest white blood cells, most uncommon, kidney-bean shaped nucleus, and destroy invading organisms and foreign material by phagocytosis.
What happens to monocytes when they leave the bloodstream?
They leave the bloodstream by diapedesis and take up residence in the tissues. They are now called macrophages, and in the lungs, they swallow any tiny particles that get in, and in the lymphatic tissue, they recognize foreign invaders.
Mononucleosis
A chronic viral disease characterized by fever, fatigue, sore throat, and a loss of appetite. It stimulates the body to produce an enormous number of monocytes.
Hemopoiesis
The process by which the formed elements of blood are made in the body.
Where does hemopoiesis take place?
The red bone marrow, though early in development lymphocytes move out to lymphatic tissue and are made there (lymph nodes, spleen, and other tissues).
What type of cell do all blood cells come from?
Hemocytoblasts, also called stem cells. The red bone marrow is full of stem cells, which are undifferentiated cells capable of dividing to produce daughter cells that can form any type of blood cell.
Hemostasis
The process by which the body stops blood loss.
What are the three stages of hemostasis?
The vasoconstriction stage, the platelet plug stage, and the coagulation stage.
Summarize the stage of vasoconstriction in hemostasis.
When a blood vessel ruptures, a reflex contraction of the broken ends of the smooth muscle that surround the vessel occurs. This closes down the tear in the blood vessel.
Summarize the stage of the platelet plug in hemostasis.
When a blood vessel is damaged, it causes a positive-feedback mechanism by which blood platelets swell, get sticky, and stick to both the blood vessel and each other. This causes the platelets to pile up at the point of damage and plug the tear to stop blood from leaking.
What is the trigger for platelet plug formation?
When a blood vessel is damaged, collagen fibers in the outer layers of the vessel are exposed to blood. This causes platelets to bind to the collagen and stimulates them to release several chemicals. The chemicals stimulates other chemical processes that cause other platelets to stick and form a plug.
Thromboxane
A chemical derived from a prostaglandin that stimulates several chemical processes that cause platelets to form a thrombus.
What is a coronary thrombosis, and what causes it?
Commonly called a heart attack. It is caused when one of the major arteries that supply the heart muscle with blood gets plugged up by a thrombus that should not be there.
What is an embolus, and what causes it?
It is a type of clot. It happens when a clot forms in a vein of the legs, breaks loose, and travel through the veins toward the heart and lungs, where it can be deadly.
Summarize the three steps of the coagulation process.
- Tissue or blood vessel damage produces prothrombinase.
- Prothrombinase converts prothrombin into thrombin.
- Thrombin converts fibrinogen into fibrin.
Prothrombinase
An enzyme produced when a blood vessel and surrounding tissue are damaged that works on prothrombin.
Prothrombin
An inactive protein produced by the liver that is constantly in the bloodstream.
Thrombin
The active form of prothrombin. It is an enzyme that works on fibrinogen.
Fibrinogen
An inactive water-soluble protein in the plasma that has the potential to become a fiber.
Fibrin
Non-water-soluble fibers that form blood clots.
Coagulation factors
Proteins in blood plasma that help initiate the blood coagulation process.
Where do most coagulation factors come from?
The liver forms most coagulation factors. The production of these proteins requires vitamin K.
What is tissue factor?
When tissues are damaged, they release lipoproteins and phospholipids into the blood. The mixture of these chemicals is called tissue factor.
What comprises the large molecule called the tissue factor/ factor VII complex?
This molecule is formed when tissue factor interacts with Ca2+ ions and the protein already in the blood, factor VII.
What activates factor X?
The interaction between the tissue factor/factor VII complex and the factor X protein activates factor X.
In the common pathway of the extrinsic pathway, what reaction produces prothrombinase?
Activated factor X reacts with factor V, phospholipids on the blood platelet membrane, and calcium ions.
What reaction activates factor XII in the intrinsic pathway?
Collagen from damaged blood vessel walls comes into contact with factor XII, a protein already in the blood, to activate factor XII.
What interaction activates factor XI in the intrinsic pathway?
Activated factor XII and factor XI react.
What interaction in the intrinsic pathway activates factor IX?
In the presence of Ca2+, the activated factor XI reacts with factor IX to make activated factor IX.
What interaction of the intrinsic pathway makes activated factor X?
Activated factor IX reacts with factor X to make activated factor X.
What reaction in the common pathway of the intrinsic pathway creates prothrombinase?
Activated factor X reacts with factor V, phospholipids on the blood platelet membrane, and calcium ions to make prothrombinase.
What three roles does the enzyme thrombin have in coagulation?
- It makes the blood clot by activating fibrinogen to make fibrin threads.
- It reacts with factor XIII to make activated factor XIII, which aids the blood clot by stabilizing it.
- It participates in a positive-feedback system.
How does thrombin participate in a positive-feedback system?
If thrombin encounters factor V, platelet phospholipids, and Ca2+, it can produce prothrombinase, which will ultimately produce more thrombin. Also, it can react with factor VIII, platelet phospholipids, and Ca2+ to make activated factor X, which can make prothrombinase. Finally, it can react with factor XI to make activated factor XI, which continues down the rest of the intrinsic pathway until it once again makes prothrombinase.
Anticoagulants
They prevent certain blood factors from being activated, thus stopping the coagulation pathways by stopping certain steps within the pathways.
What causes the difference between the four types of blood humans can have?
The difference is based on certain molecules located on the surface of the RBCs called antigens.
Antigen
A protein or other molecule that, when introduced into the body, triggers the production of an antibody.
What type of antibodies does Type A blood produce?
This blood produces antibodies against the B antigen.
What type of antibodies does Type B blood produce?
This blood produces antibodies against the A antigen.
What type of antibodies does Type AB blood produce?
This blood produces no antibodies.
What type of antibodies does Type O blood produce?
This blood produces antibodies against both A and B antigens.
How is the antibody against the Rh antigen different from the antibodies against the A or B antigen?
The antibody against the Rh antigen does not automatically appear in the blood as do the antibodies against the A or B antigen. A person must be exposed to Rh+ blood to produce the antibody.
How are people with Rh- blood exposed to Rh+ blood?
A mismatched blood transfusion or between a mother and a child.
Hemolytic disease of the newborn
During the pregnancy, the anti-Rh antibodies of the mother (who is Rh-) cross the placenta, and those antibodies attack the unborn baby’s Rh+ erythrocytes.
Arteries
Blood vessels that carry blood away from the heart.
Veins
Blood vessels that carry blood back to the heart.
Capillaries
Microscopic, thin-walled blood vessels that allow the exchange of gases and nutrients between the blood and body cells.
What are the two divisions of blood circulation?
The pulmonary circulation and systemic circulation.
Pulmonary circulation
Circulation of the blood around the alveoli (air sacs) of the lungs.
Systemic circulation
Circulation of the blood through the other tissues of the body.
What type of blood do the left and right sides of the heart handle?
The right side of the heart handles deoxygenated blood, and the left side pumps oxygenated blood.
What do the coronary arteries do?
They perform coronary circulation, which delivers blood to the cells of the heart.
Describe the characteristics of cardiac muscle.
It is striated, involuntary, made of elongated, branching cells with a single nuclei, and the cells are connected by intercalated disks, which conduct action potentials from one cell to another.
What does it mean for the heart to be self-stimulatory?
It creates its own action potentials. They can be influenced by the parasympathetic and sympathetic divisions of the ANS, but they are generated in the heart by special bundles of cardiac muscle tissue known as nodes.
What are the two nodes of the heart and where are they located?
The sinoatrial node (SA node) located in the upper portion of the right atrium and the atrioventricular node (AV node) located near the tricuspid valve in the right atrium.
Which node of the heart is also known as the pacemaker?
The sinoatrial node, as it initiates the action potentials that cause the heart to beat.
Atrioventricular bundles
Special bundles of nodal tissue that travel through the interventricular septum and then branch and travel to each ventricle.
Purkinje fibers
Fibers branched off the atrioventricular bundles that send action potentials to the cells in the ventricles.
Passive ventricular filling
When pressure in the ventricles drops, the atrioventricular valves open because the pressure in the atria is higher than in the ventricles, and blood in the atria begins flowing into the ventricles. This happens before the atria contract.
What are the two phases of the cardiac cycle?
The diastole phase and the systole phase.
Diastole phas
The phase of the cardiac cycle in which the ventricles relax.
Systole phase
The phase of the cardiac cycle in which the ventricles contract.
Cardiac cycle
One complete round of diastole and systole.
Systolic pressure
The number that reflects the pressure in the aorta when the left ventricle contracts (the systole phase). This is the maximum pressure that the aorta experiences.
Diastolic pressure
The number that reflects the minimum pressure in the aorta. This occurs right before ventricular contraction, during the diastole phase.
What are the three tunics that cover veins and arteries?
The tunica intima, the tunica media, and the tunica adventitia.
Name the four parts of the tunica intima.
The endothelium, the basement membrane, the lamina propria, and the internal elastic membrane.
Describe the structure of the tunica intima.
It is close to the blood, it consists of a slick layer of simple squamous epithelial tissue, called the endothelium, which rests on a basement membrane of connective tissue. The basement membrane is connected to a thicker layer of connective tissue called the lamina propria. This tunic is wrapped in a layer of elastic fibers called the internal elastic membrane.
Describe the structure of the tunica media.
This tunic is in between the inner and outer tunics of the blood vessel. It contains the smooth muscle that wraps around the vessel and an outer covering of elastic fibers called the external elastic membrane.
Describe the structure of the tunica adventitia.
It is the outer layer of the blood vessel and is composed of connective tissue. It blends into the surrounding tissue, holding the vessel in place.
Vasa vasorum
The set of blood vessels that supply the blood vessel walls with O2 and nutrients.
What are the two parts of a capillary?
The endothelium and the basement membrane.
Arterioles
The smallest arteries that still have three tunics. They are found between arteries and capillaries.
Venules
Small veins that do not have three tunics, but instead have only an endothelium, a basement membrane, and a few smooth muscle cells. They are found in between capillaries and the veins.
