Lab 17 Flashcards
The cardiovascular system transports
oxygen, nutrients, wastes, other solutes, and cells throughout the body.
the cardiovascular system with the pump that drives it—
the heart.
The heart is a remarkable organ, tirelessly beating more than
100,000 times per day to pump more than 8,000 liters of blood around the body
the heart is surrounded by a double-layered membrane called the
pericardium (pehr-ee-KAR-dee-um).
the heart is located in the
mediastinum and is on average about the size of a fist
Its apex is its _______ and its base is its ________
pointy inferior tip, and its base is its flattened posterior side
The heart is composed of
four chambers—the small, superior right and left atria and the larger, inferior right and left ventricles.
The chambers are separated visually by grooves on the heart’s surface:
The atrioventricular sulcus (ay-tree-oh-ven-TRIK-yoo-lur) is between the atria and ventricles, and the interventricular sulcus is between the two ventricles.
The outer most layer of the pericardium, called the
fibrous pericardium, anchors the heart to surrounding structures.
fibrous pericardium is made of
dense irregular collagenous connective tissue that is not very distensible, which helps to prevent the heart from overfilling.
The inner layer, called the
serous pericardium, is itself composed of two layers.
two layers of the serous pericardium
parietal pericardium; visceral pericardium (epicardium)
parietal pericardium
functionally fused to the fibrous pericardium. Notice that at the edges of the heart, the parietal pericardium folds over on itself to attach to the heart muscle and form the inner layer of the serous membrane called the visceral pericardium, also known as the epicardium.
epicardium
visceral pericardium
Between the parietal and visceral layers we find a thin layer of
serous fluid that occupies a narrow potential space called the pericardial cavity.
The fluid within the pericardial cavity helps the heart to
beat without friction.
The heart itself is an organ that consists of three tissue layers:
Epicardium; Myocardium; Endocardium
- Epicardium.
The epicardium (ep-ih-KAR-dee-um) or visceral pericardium is considered the outermost layer of the heart wall. It consists of a layer of simple squamous epithelial tissue and loose connective tissue
Myocardium
.2. Myocardium. The middle myocardium (my-oh-KAR-dee-um) is the actual muscle of the heart. It consists of cardiac muscle tissue and its fibrous skeleton.
Endocardium
- Endocardium. The innermost endocardium is a type of simple squamous epithelium called endothelium. It is continuous with the endothelium lining all blood vessels in the body.
The atria receive blood from
veins,
veins
which are vessels bringing blood to the heart.
The ventricles eject blood into
arteries,
arteries,
which carry blood away from the heart.
The vessels entering and exiting the heart are the largest in the
body and so are called great vessels.
There are four sets of great vessels including the following:
- Superior and inferior venae cavae; pulmonary trunk; pulmonary veins; aorta
- Superior and inferior venae cavae.
The superior vena cava (VEE-nah KAY-vah) is a large vein that drains deoxygenated blood from structures located, in general, above the diaphragm, while the inferior vena cava drains structures located, in general, below the diaphragm. Both empty into the right atrium. These veins drain a group of blood vessels collectively called the systemic circuit, in which oxygen and nutrients are delivered to cells by systemic arteries and deoxygenated blood is returned to the heart by systemic veins.
- Pulmonary trunk.
The pulmonary trunk is a large artery that exits from the right ventricle. Shortly after it forms, it splits into right and left pulmonary arteries, which deliver deoxygenated blood to the lungs through a series of vessels collectively called the pulmonary circuit. Within the pulmonary circuit, gases are exchanged, and the blood becomes oxygenated.
- Pulmonary veins.
The pulmonary veins are the portion of the pulmonary circuit that brings oxygenated blood back to the heart. There are generally four pulmonary veins, and they empty into the left atrium.
- Aorta.
The large aorta (ay-OHR-tah) is the first and largest artery of the systemic circuit. It stems from the left ventricle, after which it branches repeatedly to deliver oxygenated blood to the body’s cells.
The other set of blood vessels visible on the external surface of the heart are the vessels collectively called the
coronary circulation (KOHR-oh-nehr-ee).
The coronary arteries branch off the base of the aorta and bring oxygenated blood to
the cells of the myocardium.
The myocardium is drained by a set of
cardiac veins.