Physiology Quiz: Heart Valves and Capillary Function

Heart Function and Blood Flow

• The purpose of the four valves of the heart is to ensure one-way blood flow.
• Blood pressure is greatest in the arteries when the ventricles contract.

Blood Pressure and Circulation

• Blood pressure refers to arterial pressure in the clinical setting.
• Water is forced through capillary walls by filtration.
• The rate of blood flow is not controlled by the heart valves.

Heart Structure and Function

• The myocardium is the actual heart muscle.
• The epicardium lies on top of the visceral pericardium.
• The endocardium is the innermost layer of the heart.

Blood Cells and Oxygen

• Body cells surrounding capillaries usually have a low oxygen concentration.
• The concentration of oxygen and nutrients in the blood is important for cellular function.

Heart Problems and Diseases

• A myocardial infarction is caused by obstruction of blood flow to the heart muscle.
• Damaged heart valves, weakened heart muscle, and defective SA nodes can also cause heart problems.

Heart Valves

• The purpose of the four valves of the heart is to ensure one-way blood flow.

Blood Flow and Concentration

• Body cells surrounding capillaries usually have a low oxygen concentration.
• Water is forced through capillary walls by filtration.

Blood Pressure

• In the clinical setting, blood pressure refers to arterial pressure.
• Blood pressure is greatest in the arteries when the ventricles contract.

Heart Conditions

• A myocardial infarction is caused by obstruction of blood flow to the heart muscle.

Pericardium

• The fibrous pericardium lies on top of the visceral pericardium.

Heart Layers

• Pericardium is the membrane that covers the heart.
• Epicardium is the outermost layer of the heart wall, containing fat that helps cushion the heart.
• Myocardium is the thickest layer of the heart, made up of muscle.
• Endocardium is the innermost layer of the heart, thin and smooth.

Heart Layers and Their Characteristics

• Epicardium: outermost layer, contains fat, cushions the heart
• Myocardium: thickest layer, made up of muscle
• Endocardium: innermost layer, thin and smooth

Heart Valves

• The valve between the left atrium and left ventricle is the bicuspid (mitral) valve.

Heart Conduction System

• Purkinje fibers are found in the myocardium.

Heart Valves

• The bicuspid valve is also known as the mitral valve.
• The tricuspid valve is located between the right atrium and ventricle.
• The pulmonary semilunar valve is between the right ventricle and the pulmonary trunk.
• The aortic semilunar valve is between the left ventricle and the aorta.
• The left atrioventricular valve is also known as the mitral valve.
• The tricuspid valve prevents blood from flowing back into the right atrium.
• The mitral valve prevents blood from flowing back into the left atrium.

Cardiac Conduction System

• The bundle of His is located between the ventricles and splits into left and right branches.
• The SA node is located in the wall of the right atrium and is known as the pacemaker of the heart.
• The AV node is located between the atria and ventricles.
• The Purkinje fibers are located in the ventricular walls and help to regulate the heartbeat.
• The bundle branches are extensions of the bundle of His that carry the electrical signal to the ventricles.

Heart Valves

• The bicuspid valve is also known as the mitral valve.
• The tricuspid valve is located between the right atrium and ventricle.
• The pulmonary semilunar valve is between the right ventricle and the pulmonary trunk.
• The aortic semilunar valve is between the left ventricle and the aorta.
• The left atrioventricular valve is also known as the mitral valve.
• The tricuspid valve prevents blood from flowing back into the right atrium.
• The mitral valve prevents blood from flowing back into the left atrium.

Cardiac Conduction System

• The bundle of His is located between the ventricles and splits into left and right branches.
• The SA node is located in the wall of the right atrium and is known as the pacemaker of the heart.
• The AV node is located between the atria and ventricles.
• The Purkinje fibers are located in the ventricular walls and help to regulate the heartbeat.
• The bundle branches are extensions of the bundle of His that carry the electrical signal to the ventricles.

Cardiac Conduction System

• The Purkinje fibers are located in the walls of the ventricles and cause the ventricles to contract.
• The AV node receives the impulse from the SA node.

Bundle of His

• The bundle of His splits into left and right bundle branches that carry an electrical impulse to the Purkinje fibers.

Dysrhythmia

• Elevated potassium ions can cause dysrhythmia.

Heart Contractions

• High concentration of calcium ions can cause longer-than-normal heart contractions.

Heart Rate Regulation

• Strenuous exercise, elevated body temperature, and sympathetic nerve stimulation can increase the heart rate.
• Parasympathetic nerve stimulation can decrease the heart rate.
• Low concentration of potassium ions does not increase the heart rate.

Cardiac Control Center

• Responds to changes in blood pressure

Blood Vessel Characteristics

• Capillaries have walls that are one cell thick
• Venules and arterioles are connected by capillaries

Blood Vessel Functions

• Arteries are the strongest blood vessels that carry blood away from the heart
• Arterioles and capillaries are small vessels
• Capillaries carry oxygenated blood
• Venules and capillaries carry deoxygenated blood

Blood Pressure Regulation

• Increased cardiac output results in an increased blood pressure
• Vasodilation, loss of blood, dehydration, and shock do not directly result in increased blood pressure

Blood Pressure Regulation

• Loss of blood, dehydration, and decreased cardiac output decrease blood pressure
• Vasoconstriction increases blood pressure, whereas vasodilation decreases blood pressure

Anatomy of Veins and Arteries

• The mesenteric vein drains the intestines
• The femoral artery supplies blood to the thigh
• The maxillary artery supplies blood to the teeth
• The intercostal arteries supply blood to the rib area
• The ulnar and radial arteries supply blood to the forearm and hand
• The saphenous vein is the major vein in the legs

Veins

• Gluteal areas are served by the iliac veins.
• The mesenteric vein takes blood to the liver from the intestines.
• Blood leaves the armpits through the axillary veins.
• The azygos vein removes blood from the thorax and abdomen.

Chest Pain

• Angina is a heart-related cause of chest pain.
• Costochondritis causes chest pain only when someone pushes on the chest.
• Pleurisy causes chest pain that worsens when coughing or breathing in.
• Heartburn is not a heart-related cause of chest pain.
• Pulmonary embolism and myocardial infarction are potential causes of severe chest pain.

Heart Structure and Function

• The outermost layer of the heart wall is the epicardium, which contains fat that helps cushion the heart.
• The pericardium is a membrane that covers the heart, and it has two layers: the outer fibrous pericardium and the inner serous pericardium, which is further divided into the parietal pericardium and the visceral pericardium (also known as the epicardium).
• The myocardium is the thickest layer of the heart, made up of muscle, and it is responsible for contractions.
• The endocardium is the innermost layer of the heart, and it is a thin layer of smooth tissue.

Heart Valves

• The bicuspid valve, also known as the mitral valve, is between the left atrium and left ventricle.
• The tricuspid valve is between the right atrium and right ventricle.
• The pulmonary semilunar valve is between the right ventricle and the pulmonary trunk.
• The aortic semilunar valve is between the left ventricle and the aorta.

Cardiac Conduction System

• The sinoatrial (SA) node, located in the wall of the right atrium, is the pacemaker of the heart.
• The atrioventricular (AV) node receives the impulse from the SA node.
• The bundle of His is located between the ventricles and splits into left and right bundle branches.
• The Purkinje fibers are located in the walls of the ventricles and cause the ventricles to contract.

Blood Vessels

• Arteries are strong blood vessels that function to carry blood away from the heart.
• Venules are small vessels that carry deoxygenated blood.
• Capillaries are small vessels that allow for the exchange of oxygen and nutrients with waste products.
• Veins are blood vessels that carry blood back to the heart.

Blood Pressure and Flow

• Blood pressure is greatest in the arteries when the ventricles contract.
• Cardiac output, vasodilation, and dehydration can affect blood pressure.
• Blood flows from arteries to arterioles to capillaries to venules to veins.

Clinical Applications

• Chest pain can be caused by heart-related issues (angina) or non-heart-related issues (costochondritis, pleurisy).
• A myocardial infarction (heart attack) occurs when there is an obstruction of blood flow to the heart muscle.

Chest Pain Causes

• Chest pain caused by costochondritis generally occurs only during body movements.
• Chest pain that follows a meal and increases when the patient bends over is generally due to heartburn.

Tachycardia Management

• Vagal maneuvers might help control rapid heartbeat without medication in patients with congestive heart failure.

Congestive Heart Failure Symptoms

• Symptoms of congestive heart failure may include nausea, shortness of breath, and dizziness.
• Physical signs of congestive heart failure may include swelling of feet and ankles, and prominent neck veins.

Coronary Artery Disease Management

• A low-fat diet and regular exercise may be recommended to patients with coronary artery disease to lower cholesterol levels.
• If cholesterol levels remain unacceptably high, medication such as Lipitor may be prescribed to help lower cholesterol.

Cardiovascular System

• An aortic aneurysm is a bulge or weak area in the wall of the aorta.
• Atherosclerosis is a hardening of the fatty plaque deposits within the arteries.
• Baroreceptors, located in the aorta and carotid arteries, measure blood pressure and help regulate it.

Cardiovascular System

• Inflammation of the inner lining of the heart is called endocarditis.
• An embolus blocking a cerebral artery can cause a stroke or cerebrovascular accident.
• The cusps of the AV valve are anchored to cardiac muscle by cord-like structures called chordae tendineae.
• During ventricular relaxation, blood pressure in arteries reaches its lowest point, known as diastolic pressure.
• Fluid retention can lead to edema, a condition characterized by swelling in the legs or feet.

Blood Pressure and Heart Structure

• A consistent resting blood pressure of 140/90 mm Hg or higher is diagnosed as hypertension.
• The atria are separated from each other by a walled membrane known as the septum.
• The ventricles of the heart are separated by the interventricular septum.

Blood Circulation

• The pulmonary circuit is the route that blood takes from the heart to the lungs and back to the heart again.

Heart Function

• After the impulse flows through the atrioventricular (AV) node, the ventricles contract and the sinoatrial (SA) node starts the flow of a new impulse.

Blood Circulation Pathway

• The blood takes a circular route from the heart through the body and back to the heart, known as the circulatory circuit.

Blood Pressure Regulation

• The pressure in the arteries caused by ventricular contraction is referred to as systolic pressure.
• Constriction of the muscular wall of an artery, which increases blood pressure, is called vasoconstriction.
• Dilation of the wall of an artery, which decreases blood pressure, is called vasodilation.

Vein Abnormalities

• Twisted, dilated veins, typically seen in the legs, are known as varicose veins.

Blood Composition

• The percentage of red blood cells found in a sample of blood is called the hematocrit.
• Plasma makes up approximately 55% of the blood.

Red Blood Cell Production

• The production of RBCs in the blood is controlled by the hormone erythropoietin.
• Red blood cells live for approximately 4 months.

White Blood Cells

• Bacteria and viruses are destroyed by white blood cells called neutrophils.
• Parasitic infections can be controlled by eosinophils.

White Blood Cells (WBCs)

• Basophils release histamine and heparin, promoting inflammation.

Infection and WBC Differential

• A bacterial infection present for about 2 weeks would show elevated monocytes in the WBC differential.

AIDS and WBCs

• Patients with AIDS would have decreased lymphocytes.

WBC Movement

• Diapedesis is the mechanism by which WBCs leave blood vessels.

Blood Platelets

• Blood platelets are essential for clotting.

Blood Coagulation

• Blood coagulation on a vessel wall in the absence of a known injury is correctly referred to as a thrombus.

Blood and Transfusions

• A broken part of a thrombus is referred to as an embolus.
• An embolus is dangerous because it can become lodged in a small artery in the lungs.

Blood Mismatch

• When mismatched blood is given to a patient, the blood received will be destroyed.
• No other major problems will result from receiving mismatched blood.

Blood Types

• People with O blood type are universal donors.
• People with AB blood type can receive only one type of blood.

Rh Type and Pregnancy

• A woman's Rh type is important to know because if she is Rh-negative and conceives a child that is Rh-positive, her second baby will have erythroblastosis fetalis.

Plasma Proteins

• Globulins are plasma proteins that transport lipids and some vitamins, aid in blood clotting, and help control bleeding
• Fibrinogen is a plasma protein that aids in blood clotting

Blood Clotting

• When a blood vessel is broken, the body's first response is platelet plug formation
• Blood coagulation follows platelet plug formation
• Blood clot formation is the final response to a broken blood vessel

Blood Types

• AB is a rare blood type
• People with type AB blood can receive blood from people with type AB blood only
• Type AB blood is not the most common type of blood
• People with type AB blood are not universal donors

Polycythemia Vera

• Polycythemia vera is a condition characterized by frequent headaches, dizziness, and shortness of breath
• Treatment for polycythemia vera typically involves therapeutic phlebotomy

Patient Symptoms and Possible Conditions

• Beth, a 16-year-old patient, complains of fatigue, frequent headaches, and cold feet.
• She has heavy menstrual bleeding for 7-8 days each month.
• Possible conditions: Iron-deficient anemia (B) due to heavy menstrual bleeding.

Blood Clot Formation

• The formation of a blood clot is called coagulation (C).
• Coagulation involves the formation of a mesh that entraps blood cells and platelets.
• Fibrin (A) sticks to the damaged area of the blood vessel, creating this mesh.

Complications of Blood Clots

• If an embolus lodges in a coronary artery, it may cause myocardial infarction (E), a heart attack.
• An embolus in a blood vessel can also cause pulmonary embolism (B), a blockage in the lungs.

Agglutination and Blood Transfusions

• Agglutination is the clumping of blood cells, which can occur following a blood transfusion.
• The most likely result of agglutination following a blood transfusion is a severe reaction, potentially leading to a cerebrovascular accident (A) or other complications.

Blood Transfusions and Blood Types

• Harold, with A-positive blood, can receive A-negative blood if necessary.
• Type A blood is compatible with A-positive and A-negative blood.

Erythroblastosis Fetalis

• An Rh-negative mother is most at risk for erythroblastosis fetalis.
• The condition occurs when an Rh-negative mother is pregnant with an Rh-positive fetus.
• Medical intervention often required at birth is exchange transfusions (not an option in the provided answers).

Anemia

• The most common cause of anemia is iron deficiency.
• Anemia can be caused by AIDS, as in Harold's case.

Sickle Cell Anemia

• The population most affected by sickle cell anemia is African Americans.
• Signs or symptoms of sickle cell anemia include enlarged spleen and delayed growth.

Blood Volume

• The average adult body contains between 4 to 6 liters of blood.

White Blood Cell Count

• A normal WBC count is approximately 3,800 cells.

Thalassemia

• Patients of Mediterranean descent are most likely to have thalassemia.

Blood Transfusion and Cellular Components

• Clumping of red blood cells following a blood transfusion is a notable phenomenon.

White Blood Cell Characteristics

• Monocytes and lymphocytes are two types of white blood cells that lack granules in their cytoplasm.

Anemia and Oxygen Transportation

• When there are insufficient red blood cells or hemoglobin in the blood, the body's cells receive inadequate oxygen, leading to a condition called anemia.

White Blood Cell Functions

• Basophils, a type of white blood cell, release substances like histamine, which promotes inflammation, and heparin, an anticoagulant.

Liver Function and Bile Production

• The liver utilizes an orange pigment called bilirubin to produce bile necessary for fat digestion.

Blood Cells and Components

• When a red blood cell is destroyed, a pigment called bilirubin is released.
• Deoxyhemoglobin is hemoglobin that is not carrying oxygen and may carry carbon dioxide, also known as reduced hemoglobin.
• There are several types of lipoproteins in blood, including very low-density lipoproteins (VLDL), low-density lipoproteins (LDL), high-density lipoproteins (HDL), and chylomicrons.
• Blood coagulation is the process where a blood clot replaces the platelet plug at the site of a blood vessel injury.
• Granulocytes are a type of white blood cell that contain granules in their cytoplasm, including neutrophils, eosinophils, and basophils.

Blood Proteins and Cells

• Lipoproteins, a type of blood plasma protein, are responsible for transporting lipids and certain fat-soluble vitamins.

Leukocytes (White Blood Cells)

• Leukocytes are categorized into two main groups: granulocytes and agranulocytes.

Blood Cell Production

• Red bone marrow produces most blood cells, with the process facilitated by stem cells.

Anemia

• Hemolytic anemia is a condition where red blood cells are destroyed at a faster rate than they can be produced.

Abnormal White Blood Cells

• Leukemia is a condition characterized by the bone marrow producing an abnormal large number of white blood cells.

White Blood Cells (WBCs)

• WBCs are also referred to as leukocytes.
• A WBC count above 10,000 cells per cubic millimeter of blood indicates leukocytosis, likely indicating a bacterial infection.
• A below-normal WBC count is known as leukopenia.

Lipid Transport

• Lipids are not water-soluble and require combination with molecules called lipoproteins for transport in plasma, which is mostly water.
• Lipoproteins enable lipid transport in the bloodstream.

Immunity

• White blood cells responsible for providing immunity to the body are the lymphocytes.

Hemoglobin and Blood Components

• Hgb is the abbreviation for hemoglobin.
• Hemoglobin is a critical component of red blood cells (RBCs) that carries oxygen throughout the body.

Plasma Proteins and Blood Pressure

• Albumins are the smallest of the plasma proteins that help maintain blood pressure by pulling water into the bloodstream.
• Other types of plasma proteins include fibrinogen and globulins.

Heart and Blood Vessels

• The pericardium is a membrane that covers the heart, with three layers: epicardium, myocardium, and endocardium.
• The epicardium is the outermost layer, containing fat that cushions the heart.
• The myocardium is the thickest layer, made up of muscle.
• The endocardium is the innermost layer, thin and smooth.
• The atrioventricular (AV) node is located in the wall of the right atrium and receives impulses from the SA node.
• The bundle of His splits into left and right bundle branches, carrying electrical impulses to the ventricles.
• The SA node, located in the wall of the right atrium, is the pacemaker of the heart.

Blood Pressure and Blood Flow

• Blood pressure increases with cardiac output, total peripheral resistance, and blood volume.
• Vasodilation decreases blood pressure, while vasoconstriction increases it.
• Blood flows through the heart in the following order: atria, ventricles, pulmonary trunk, lungs, pulmonary veins, left atrium, left ventricle, aorta, and peripheral arteries.

Blood Vessels

• Arteries are strong, elastic vessels that carry blood away from the heart.
• Arterioles are smaller, muscular arteries that regulate blood pressure.
• Capillaries are the smallest blood vessels, allowing for diffusion of oxygen and nutrients.
• Venules are small vessels that collect blood from capillaries.
• Veins are larger, thinner vessels that carry blood back to the heart.

Blood

• Plasma makes up 55% of blood, carrying proteins, nutrients, and waste.
• Red blood cells (RBCs) carry oxygen, produced in red bone marrow, and live for approximately 120 days.
• White blood cells (WBCs) fight infection and are divided into granulocytes and agranulocytes.
• Platelets are essential for blood clotting, produced in red bone marrow.

Blood Types

• The ABO blood group system has four types: A, B, AB, and O.
• The Rh blood type system has positive (Rh+) and negative (Rh-) types.
• Type O blood is the universal donor type, and type AB is the universal recipient type.

Blood Disorders

• Anemia is a deficiency of RBCs or hemoglobin, causing fatigue, weakness, and pallor.
• Polycythemia vera is an overproduction of RBCs, causing hypertension and blood clots.
• Erythroblastosis fetalis is a condition where maternal antibodies attack fetal RBCs, causing anemia and jaundice.

Other

• The cardiac conduction system regulates heart rhythm, with the SA node, AV node, bundle of His, and Purkinje fibers.

• Dysrhythmia is an abnormal heart rhythm, caused by elevated potassium ions, sympathetic nerve stimulation, or other factors.### Blood and Circulatory System

• Anemia is a condition where there are not enough red blood cells or hemoglobin in the blood to carry an adequate amount of oxygen to the body's cells.

• Basophils are white blood cells that release substances such as histamine, which promotes inflammation, and heparin, which is an anticoagulant.

• The liver uses an orange pigment called bilirubin to make bile needed for the digestion of fats.

• Biliverdin is a pigment released from a destroyed red blood cell.

Hemoglobin and Lipoproteins

• Hemoglobin that is not carrying oxygen is called deoxyhemoglobin, and because it may now carry carbon dioxide, it is also called carbaminohemoglobin.
• There are different types of lipoproteins found in blood, including very low-density lipoproteins (VLDL), low-density lipoproteins (LDL), high-density lipoproteins (HDL), and chylomicrons.

Blood Clotting and White Blood Cells

• The process of a blood clot replacing the platelet plug at the site of a blood vessel injury is called blood coagulation.
• White blood cells (WBCs) are also called leukocytes.
• If a patient has a white blood cell count above 10,000 cells per cubic millimeter of blood, the patient has leukocytosis and probably has a bacterial infection.
• A white blood cell count that is below normal is called leukopenia.

Lipid Transport and Immunity

• Lipids must combine with molecules called lipoproteins to be transported in the bloodstream.
• The white blood cells that provide immunity for the body are the lymphocytes.

Blood Cell Counts and Heart Function

• The abbreviation used for the term hemoglobin is Hgb.
• Albumins are the smallest of the plasma proteins that pull water into the bloodstream to help maintain blood pressure.
• The formation of a blood clot is called coagulation.
• The purpose of the four valves of the heart is to ensure one-way blood flow.
• Body cells surrounding capillaries usually have a low oxygen concentration.
• Water is forced through capillary walls by filtration.
• In the clinical setting, blood pressure refers to arterial pressure.
• Blood pressure is greatest in the arteries when the ventricles contract.
• A myocardial infarction is caused by obstruction of blood flow to the heart muscle.
• The parietal pericardium lies on top of the visceral pericardium.