Cardiovascular Physiology Quiz

Circulatory System Overview

• The circulatory system transports fluids throughout the body.
• It consists of two interconnected parts that function in parallel: the Cardiovascular and Lymphatic systems.
• The Cardiovascular System includes the heart, blood vessels, and blood.
• The Lymphatic System includes lymphatic organs, lymphatic vessels, and lymph.

Cardiovascular System Objectives

• Students are expected to explain the general functions of the circulatory system.
• Students are to describe the components of the cardiovascular system.
• Students need to list the different types of blood cells and their functions.
• Students will be able to describe the composition of plasma and the specific functions of plasma proteins.
• Students will describe the location of the heart and its functions.
• Students will be asked to describe the heart wall and coverings.
• Students will be asked to discuss the blood supply and innervation of the heart.
• Students will be required to trace the path of blood through the heart, naming its chambers and valves.
• Students will need to name the three types of blood vessels and describe their structure and function.
• Students will need to discuss the lymph system, including vessels, nodes, thymus and spleen.
• Explain the relationship between the lymphatic system and the circulatory system and the role of lymphoid tissue structures and lymphocytes in a body’s defense

Functions of the Circulatory System

• Distributes nutrients
• Transporters and exchange of oxygen and carbon dioxide
• Removal of waste materials
• Distributes secretions of endocrine glands
• Prevents excessive bleeding
• Prevents infection
• Regulates body temperature and pH

Major Parts of the Cardiovascular System

• Blood Vessels: Define routes of blood flow.
• Heart: Pumps/pushes blood through the body.
• Blood: Is a liquid connective tissue.

Blood - Function

• Transportation: Transports oxygen, nutrients, hormones, and waste products.
• Regulation: Maintains fluid balance, pH, and temperature.
• Protection: Includes blood clotting and immune responses.

Blood Composition and Characteristics

• Blood is about 8% of total body weight; 7.35 to 7.45 pH range.
• Approximately 5-6 liters in an adult male; 4-5 liters in an adult female
• Blood appears thick and homogeneous to the naked eye, but microscopic examination shows cellular and liquid components.

Formed Elements of Blood

• Includes blood plasma (55%) and formed elements (45%).
• Blood plasma is a liquid extracellular matrix with dissolved substances (water, proteins, ions, nutrients, and wastes).
• Formed elements are mainly red blood cells (RBCs) with less than 1% of leukocytes and platelets.

Blood - Components of Blood Plasma

• Blood plasma is a straw-colored, sticky fluid.
• Although it is mostly water (about 90%), it also contains over 100 different kinds of molecules such as ions (Na+, Cl-), nutrients, waste products (urea, ammonia, and carbon dioxide), and oxygen, hormones, and vitamins.
• Blood plasma contains three main types of proteins: albumin, globulin, and fibrinogen.
• Serum is plasma with the clotting factors removed.

Blood - Blood Cells

• Erythrocytes (Red Blood Cells):
  • Have a biconcave shape; about 4.3-5.2 million per cubic millimeter in women and 5.1-5.8 million in men.
  • Lack a nucleus and organelles.
  • Their cytoplasm is packed with hemoglobin, a protein that carries oxygen.
  • Live for 100-120 days.
• Leukocytes (White Blood Cells):
  • Have nuclei and do not contain hemoglobin, thus appearing colorless.
  • Less numerous than erythrocytes but larger.
  • Can move in an ameboid fashion, protecting the body from infectious microorganisms.
  • Capable of functioning outside the bloodstream.
  • Leave capillaries through a process called diapedesis.
  • A leukocyte count over 11,000 per cubic millimeter indicates infection/inflammation (leukocytosis.)
• Platelets (Thrombocytes):
  • Smallest formed elements (2-4 µm).
  • Formed from large cells called megakaryocytes (lack nuclei/organelles).
  • Involved in blood clotting via amoeboid movement and other actions.

Blood - Blood Cell Types

• Granulocytes

• Neutrophils, eosinophils, basophils.

• Larger and much shorter-lived than erythrocytes

• Functionally, all granulocytes are phagocytic

• Have variable-shaped nuclei

• Neutrophils: 2-6 lobed nuclei, most abundant leukocyte (constitute 60%). First to respond to bacterial invasion

• Eosinophils: Bilobed nuclei, account for 1-4% of all leukocytes and primarily fight parasites.

• Basophils: Bilobed nuclei, account for 0.5-1% of all white blood cells, and release histamine and other inflammatory mediators.

• Agranulocytes

• Lymphocytes: 20-45% of all leukocytes. Effective in fighting infectious organisms because each lymphocyte recognizes and acts against a specific foreign molecule. B cells, T cells, and NK cells

• Monocytes: 12-20 µm diameter, largest leukocytes, makes up 4-8% of WBC. Phagocytosis after transforming into fixed or wandering macrophages

• Platelets: The smallest formed elements (2-4 µm) formed from large cells called megakaryocytes that are crucial in blood clotting. They are also capable of amoeboid movement.

Heart - Structure and Location

• Hollow, muscular, four-chambered organ.
• Weighs approximately 250-350 g in adults (about the size of a clenched fist).
• Rests on the diaphragm near the midline of the thoracic cavity in the mediastinum.
• Two-thirds of the heart is located on the left side of the body.
• Has an apex (pointed end) and a broad base opposite to the apex.

Heart - Coverings

• Pericardium: Protective membrane surrounding the heart, with a fibrous pericardium (tough, inelastic, dense irregular connective tissue) and a serous pericardium (thinner membrane).
• The serous pericardium has a parietal layer (outer layer) that is sensitive to pain and a visceral layer (inner layer) attached to the heart wall that is insensitive to pain.
• Pericardial fluid within the cavity between the layers reduces friction between the heart and its outer layers, preventing external pressure.

Heart - Layers

• The heart has three main layers:
  • Epicardium (outer layer
  • Myocardium (thickest layer, largely cardiac muscle)
  • Endocardium (inner most layer; a thin layer of unique epithelial tissue that lines the entire circulatory system)

Heart - Chambers

• Right atrium: Receives deoxygenated blood from the superior vena cava, inferior vena cava, and coronary sinus.
• Right ventricle: Pumps blood to the lungs via the pulmonary trunk through the pulmonary valve, with three leaflets.
• Left atrium: Receives oxygenated blood from the lungs through the pulmonary veins.
• Left ventricle: Pumps blood to the body via the aorta through the aortic valve, with three leaflets.

Heart - Valves

• Atrioventricular (AV) Valves: (Tricuspid and Bicuspid)
• Semilunar Valves: (Aortic and Pulmonary)
• Chordae tendineae attach cusps to papillary muscles
• Prevents backflow of blood, maintaining one-way blood flow.

Heart - Blood Supply

• The heart is supplied by coronary arteries, which arise from the aorta, primarily bifurcating into anterior interventricular and circumflex branches on the left and a right coronary artery.
• Coronary sinus, a wide venous channel along coronary sulcus that collects the heart's venous blood and drains into the right atrium.

Heart - Conduction System

• Sinoatrial (SA) node: The pacemaker of the heart, initiating the heartbeat.
• Atrioventricular (AV) node: Delays the impulse from the SA node before passing it to the ventricles, allowing the atria to contract before the ventricles.
• AV bundle (bundle of His): Transmits the impulse to the ventricles.
• Right and left bundle branches: Carry the impulse to the apex of the heart.
• Purkinje fibers: Distribute the impulse throughout the ventricle walls, causing them to contract.

Heart Sounds

• "Lub": The first heart sound, caused by closing of AV valves.
• "Dup": The second heart sound, caused by closing of semilunar valves.

Mediastium (location and structure)

• The mediastinum is the space between the two lungs, in the thoracic cavity, and superiorly extends to the superior thoracic aperture (superiorly) and inferiorly to the diaphragm.
• The mediastinum contains all thoracic visceral and structures except the lungs, and is divided into superior and inferior parts, which include various vessels, lymph nodes, nerves, and fat.

Heart - Arterial Blood Supply and Venous Drainage(general overview)

• Coronary arteries: Supply oxygenated blood to the heart muscle.
• Coronary veins: Drain deoxygenated blood from the heart muscle.

Hepatic Portal System (general overview)

• A unique venous system that transports blood from the digestive organs (stomach, small intestine, and spleen) to the liver for processing and detoxification before returning to general circulation.

Fetal Circulation(general overview)

• Umbilical arteries bring deoxygenated blood and fetal waste products to the placenta.
• Umbilical vein carries oxygenated blood and nutrients from the placenta to the fetus.
• Foramen ovale: A shunt from the right atrium to the left atrium, bypassing the lungs.
• Ductus arteriosus: A shunt from the pulmonary trunk to the aorta, bypassing the lungs.

Adult Derivatives of Fetal Circulation

• Fossa ovalis: The fetal foramen ovale closes after birth, becoming the fossa ovalis.
• Ligamentum arteriosum: The ductus arteriosus constricts and becomes the ligamentum arteriosum.
• Umbilical ligaments: The umbilical arteries and vein become the medial umbilical ligaments.
• Ligamentum venosum: The ductus venosus closes and becomes the ligamentum venosum.
• Round ligament (ligamentum teres): The umbilical vein becomes the round ligament (ligamentum teres).

Lymphatic System Overview

• A circulatory system for fluid return, which returns excess tissue fluid back into the bloodstream.
• It also removes antigens from the body and exposes them to the immune system.

Lymphatic System - Lymph

• Lymph is a clear, watery fluid similar in composition to plasma but with an absence of plasma proteins. It is identical in composition to interstitial fluid.
• Transports plasma proteins and larger particles (bacteria, cell debris) from the capillary beds into the bloodstream.

Lymphatic System - Lymphatic Vessels

• Lymphatic collecting vessels
• Lymphatic trunks
• Lymphatic ducts
• Carry lymph toward the heart, following the general direction of blood flow, with one-way valves.
• Fluid flows only toward the heart (unlike the circulatory system.)
• Lymph is propelled by skeletal muscle contractions, artery pulsations, and smooth muscle contractions in the wall of lymphatic vessels.

Lymphatic System - Lymphatic Veins

• Collect excess tissue fluid from tissues.
• Collect blood proteins away from capillaries.
• Lymph nodes: Sites of lymph cleansing.

Lymphatic System - Lymph Nodes (Structure/Function)

• Bean-shaped organs located along lymphatic collecting vessels.
• Filter lymph, removing pathogens and foreign particles.
• Sites for lymphocyte proliferation. (filtering pathogens to engage the immune responses.)

Lymphatic System - Lymph Trunks

• Lumbar trunks: Receive lymph from the lower limbs.
• Intestinal trunks: Receive chyle from the digestive tract.
• Bronchomediastinal trunks: Receive lymph from the thorax.
• Subclavian trunks: Receive lymph from the upper limbs and thoracic wall
• Jugular trunks: Receive lymph from the head and neck

Lymphatic System - Lymphatic Ducts

• Thoracic duct: Drains lymph from three-quarters of the body, empties into the left subclavian vein.
• Right lymphatic duct: Drains lymph from the upper right side of the body, empties into the right subclavian vein.

Lymphatic System - Spleen (Structure/Function)

• The largest lymphoid organ.
• Located in the left upper quadrant of the abdomen, between the diaphragm and the stomach.
• Functions in filtering blood (removing abnormal blood cells and antigens).
• Stores blood platelets and macrophages for immune responses.
• Functions in hematopoiesis (blood formation) during fetal development .

Lymphatic System - Thymus

• Located in the upper mediastinum, posterior to the sternum.
• Plays a crucial role in the maturation of T lymphocytes (a type of white blood cell.)
• Diminishes in size and function as an individual ages.

Blood Vessels(general overview)

• Arteries carry blood away from the heart.
• Veins carry blood to the heart.
• Capillaries form a network between arteries and veins for exchange of nutrients, gases, and waste products.

Blood Vessels - Tunics

• Tunica intima
• Tunica media
• Tunica adventitia (or externa)

Blood Vessels - Types of Arteries

• Elastic arteries
• Muscular arteries
• Arterioles

Blood Vessels - Capillaries

• Tiny blood vessels with thin walls, facilitating exchange of substances. (nutrients, oxygen, carbon dioxide, and waste).
• Classified by continuous, fenestrated, or sinusoid types.

Blood Vessels - Veins

• Larger-diameter vessels that carry deoxygenated blood back to the heart.
• Contain valves that prevent backflow of blood

Arteries of the Head, Neck, and Upper Limbs

• Common carotid artery
• Internal carotid arteries
• External carotid arteries
• Subclavian arteries
• Axillary arteries
• Brachial arteries
• Radial arteries
• Ulnar arteries

Arteries of the Thorax

• Descending aorta (thoracic portion)
• Branches supply the esophagus, bronchi, pericardium, mediastinal structures, posterior intercostal arteries, and superior phrenic arteries

Arteries of the Abdomen, Pelvis, and Lower Limbs

• Abdominal aorta
• Unpaired branches (celiac trunk, superior and inferior mesenteric arteries)
• Paired branches (inferior phrenic, renal, suprarenal, testicular/ovarian, and lumbar arteries.
• Common iliac arteries
• Internal iliac arteries
• External iliac arteries
• Femoral arteries
• Popliteal arteries
• Tibial arteries
• Fibular arteries

Venous Drainage(general overview)

• Veins drain blood back to the heart.
• Many superficial and deep veins accompany the arteries, draining blood from specific regions (e.g., head, neck, upper limbs, lower limbs).
• Venous systems contain valves to prevent backflow of blood.

Test your knowledge on cardiovascular physiology with this quiz. Questions cover the anatomy of the heart, its functions, and related structures such as arteries and veins. Perfect for students studying anatomy or physiology.