What lies in the mediastinum, behind the body of the sternum between the points of attachment of ribs 2-6?
What is the shape of the heart at birth?
Transvers and appears lage in proportion to the diameter of the chest cavity
What are the 3 distinct layers that comprise the heart wall (superficial to deep)?
What is the thick, contractile middle layer of the heart wall; that compresses the heart cavities and blood within them with great force?
What are the characteristics of the Myocardium within the atria?
-Not very thick because little pressure is needed to move blood such a small distance
What are the Ventricles also known as?
"pumping chambers" (because they push blood into the large network of vessels)
What is the characteristics of the Myocardium within the ventricles?
-Thicker than the atria because great force must be generated to pump the blood a large distance
Which ventricle's myocardium is thicker and why?
Left ventricle is thicker than the right because it must push blood much further
What are the mechanical devices that permit the flow of blood in one direction only?
Valves of the heart
What prevents blood from flowing back into the atria from the ventricles when the ventricles contract?
Atrioventriclular (AV) valves
What are the free edges of the three flaps of endocardium that make up the tricuspid valve attached to papillary muscles by?
What is similar in structure to the tricuspid valve except only having two flaps present?
What are the half-moon shaped flaps growing out from the lining of the pulmonary artery and aorta; preventing blood from flowing back into the ventricles from the aorta and pulmonary artery?
Semilunar (SL) valves
What is a set of connected rings that serve as a semirigid support for the heart valves and for the attachement of cardiac muscle of the myocardium?
Skeleton of the heart
What serves as an electrical barrier between the myocardium of the atria and myocardium of the ventricles?
Skeleton of the heart
What is characterized by listening to the sounds of the heart on the body surface with a stethoscope?
What is the flow of blood in the right side of heart from begining until it enters the Left side of the heart?
-Right Atrium through R Atriventricular valve into the R Ventricle
-From R Ventricle through Pulmonary Semilunar valve into the Pulmonary artery, the Pulmonary trunk
-Pulmonary trunk branches to form L and R Pulmonary arteries which conduct gas exhange with lungs
-From lungs blood flows through Pulmonary Veins into L Atrium
What is the flow of blood in the left side of the heart from blood from pulmonary veins flowing from lungs into the left Atrium?
-Blood from pulmonary veins flows into Left Atrium which passes through the L AV valve into the L Ventricle
-From L Ventricle blood flows through Aortic Semilunar valve into the Aorta
-Branches of the aorta supply all the tissues of the body except the gas exchanging tissues of the lungs
Where does blood leaving the head and neck and chest walls tissues empty?
Into the superior vena cava
Few anastomoses (connections between vessels) exist between the larger branches of what?
As a rule veins of the coronary circulation follow a course that closely parallels that of what?
After blood goes through the cardiac veins where does it enter?
Coronary sinus to drain into right atrium
What makes up the Conduction system of the heart?
-Sinoatrial (SA) node
-Atrioventricular (AV) node
What consists of hundreds of cells in the right atrial wall near the opening of the superior vena cava?
Sinoatrial (SA) node
What is the small mass of special cardiac muscle in right atrium along lower part of interatrial septum?
Atrioventricular (AV) node
What is a bundle of special cardiac muscles fibers that originate in the AV node extends by two branches down the two sides of the interventricular septum, and continues as purkinje fibers?
What is located near the arch of the aorta is made up of the combination of sympathetic and parasympathetic fibers?
Fibers from the Cardiac Plexus enter the heart by accompanying what?
Right and left Coronary arteries entering the heart
Most fibers from the cardiac plexus end where?
SA node but some end in the AV node in the atrial myocardium
What accommodate the surge of blood when the heart contracts and is able to recoil when ventricles relax?
What are the characteristics of Muscular (distributing) arteries?
-Smaller in diameter than elastic arteries
-Muscular layer is thick
What are short connecting vessels between true arteriole and 20-100 capillaries that are encircled by precapillary sphincters?
What type of blood vessel is not evenly distributed which contains the highest numbers in tissues with high metabolic rate and may be absent in some "avasular" tissues such as cartilage?
What provide a smooth luminal surface that protects against intravascular coagulation?
Lining endothelial cells
What contains intercellular clefts, cytoplasmic pores, and fenestrations that allow exchange to occur between blood and tissue fluid?
Lining endothelial cells
What exhibit a woven appearance and function to strengthen and keep the lumen of a vessel open?
What form highly elastic networks and play important roles in creating passive tension to help regulate blood pressure throughout the cardiac cycle?
What is present in all segments of vascular system except capillaries that exert active tension in vessels when contracting?
Smooth muscle fibers
What occurs when blood flows from an artery directly into a vein?
Arteriovenous anastomoses or shunts
Venous blood from the head, neck, upper extremities, and thoracic cavity (except lungs) drains into what?
Superior Vena Cava
Veins from the spleen, stomach, pancreas, gallbladder, and intestines send their blood to the what?
Liver via the Hepatic Portal Vein
In the liver, venous blood mingles with arterial blood in the capillaries and is eventually drained from liver by what to where?
By Hepatic Veins that join the Inferior Vena Cava
What are the extensions of internal iliac arteries; which carry fetal blood to placenta?
Two umbilical arteries
What is attached to uterine wall, and is where exchange of oxygen and other substances between the separated maternal and fetal blood occurs?
What returns oxygenated blood from placenta to fetus; enters body through umbilicus and goes to undersurface of liver, where it gives off two or three branches and then continues as ductus venosus?
What is the continuation of umbilical vein, which bypasses the undeveloped liver and drains into inferior vena cava?
What is the small vessel connecting pulmonary artery with descending thoracic aorta of a fetus?
The umbilical vein within the baby's body becomes what after the umbilical cord is cut?
The round ligament of the liver
What functionally closes shortly after a newborn's first breath and pulmonary circulation is established; structural closure takes approximately 9 months
What contracts with establishment of respiration, and becomes the ligamentum arteriosum?
The Ductus venosus becomes what after the umbilical cord is cut?
The ligamentum venosum of the liver
Throughout adulthood heart valves and myocardial tissue degenerate which do what?
Reduces pumping efficiency
What vessels arise off the Aortic Arch?
-Left Common Carotid Artery
-Left Subclavian Artery
What vessels arise off the Brachiocephalic Artery?
-Right Subclavian Artery
-Right Common Carotid Artery
What is the sequence of the Common Iliac artery proximal to distal?
Common illiac arter turns int the External Iliac Artery which turns into the Femoral artery
What vessels supplies the anterior portion of the head?
Right/Left Common Carotid Arteries to Right/Left Internal Carotid Arteries to Anterior Cerebral Arteries
What vessels supply the posterior portion of the head?
Right/Left Subclavian Arteries to Right/Left Vertebral Arteries to Basilar Artery to Posterior Cerebral Arteries
What connects the anterior and posterior vessels that supply the head?
Posterior communicating artery
What connects the right and left sides of the anterior vessels that supply the head?
Anterior communicating artery
What does the connection of the Anterior/Posterior communicating arteries form when they connect?
Circle of Willis