The Heart

chordae tendineae

"heart strings" are tiny white collagenic cords that anchor the cusps to the ventricular walls. They originate from the papillary muscles.

Explain how veins serve as a blood reservoir for the cardiovascular system:

-over half of the blood of the systemic circuit is given to veins -at rest 70% of blood in systemic circulation -systemic veins has 55% of blood -blood can be moved from veins into circulation via vasoconstriction of veins (ex; when more blood needed during exertion) -blood can be shifted back into reservoirs via vasodilation (ex; when less blood needed during rest)

Heart chambers

1)right atrium- upper chambers; internally separated by interatrial septum 2)right ventricle- lower chamber; internally separated by interventricular septum; wall of 3)left atrium- upper chamber; internally separated by interatrial septum 4)left ventricle- upper chamber; internally separated by interventricular septum; larger than the right ventricle, needed to pump with more pressure to systemic circuit

systemic circulation List the arteries that carry blood away from the left ventricle of the heart to the major areas of the body:

Aorta

Blood Vessels

Are the channels or conduits through which blood is distributed to body tissues. The vessels make up two closed system of tubes that begin and end at the heart. One system, the pulmonary vessels transports blood from the right ventricle to the lungs and back to the left atrium.

The characteristics of Vein and Arteries

Arteries 1) have strong muscular, elastic walls 2) lumen is pretty narrow 3) bring blood to other body parts from the heart 4) bear blood, that is oxygenated (except) pulmonary artery) Veins 1) have walls that are thin, non elastic 2) lumen is spacious 3) carry blood from other areas of the body to heart 4) carry blood that is deoxygenated (except pulmonary vein)

Characteristics of the Pulmonary and Systemic Circulation identify features of the Pulmonary circulation that distinguishes it from Systemic:

Pulmonary circulation: -carries deoxygenated blood from the right ventricle of the heart to the lungs through a pulmonary artery -carries oxygenated blood from the lungs to the left atrium of the heart by the pulmonary vein -composed of pulmonary artery and pulmonary vein -carries blood to the lungs -helps to release carbon dioxide from the blood while dissolving oxygen in the blood Systemic circulation: -carries oxygenated blood from the left ventricle of the heart to the rest of the body by the aorta -carry's deoxygenated blood from the body to the right atrium of the heart by the superior/inferior vena cava -composed of inferior and superior vena cava, aorta, and other small blood vessels -carries blood throughout the body -helps to provide nutrients and oxygen to the metabolizing cells in the body

Identify the coronary arteries and describe the specific areas of the heart supplied by their major branches:

R coronary artery (RCA) - 2 branches • Posterior interventricular artery - runs around posterior & down toward Apex, supplies blood to posterior surface of both ventricles • Marginal artery - runs down toward apex, supplies blood to right border of heart • L coronary artery (LCA) - 2 branches • Anterior interventricular artery - runs down IV septum, supplies blood to both ventricles & most IV septum • Circumflex artery - runs around heart to posterior & down toward apex, supplies blood to left atrium & ventricle

Describe the structure and function of Capillaries:

Smallest structure connects arterioles and venules

General function of the Heart

The cardiovascular system consists of the heart, blood vessels, and the blood. this system has three main functions. *Transport of nutrients, oxygen, and hormones to cells throughout the body, and removal of metabolic wastes. (Carbon dioxide, nitrogenous wastes)

Location and Position of the Heart

The heart is located posterior to the sternum left of the body midline between the lungs in the mediastinum. The position of the heart is slightly rotated such that its right side or right border (primarily formed by the right atrium and a small part of the right ventricle) is located more anteriorly, while its left side or left border (primarily formed by the left atrium and left ventricle) is located more posteriorly. It projects slightly anteroinferiorly toward the left side of the body with the right ventricle lying on the diaphragm.

List the structural components of the pericardium:

The pericardium that encloses the heart includes the pericardial sac, which has an outer fibrous pericardium and an inner parietal layer of serious pericardium, and a visceral layer of serous pericardium (epicardium) that forms the outer layer of the heart wall.

Superficial Features of the Heart Compare the superficial features of the Anterior/ Posterior aspects of the heart:

The right side of the heart is more visible from the anterior view, and the left side of the heart is more visible from the posterior view,

Describe the structure and general function of Vein:

carry blood back to the heart, low pressure, larger lumen, have numerous valves

Heart valves

***1) Tricuspid valve- when the atria fills to capacity these valves open to allow blood to flow from right atrium into the right ventricle. 2) Pulmonary valve- acts like a one way door from your hearts right ventricle to the lungs, blood flows from the right ventricle through the valve. ***3) Mitral valve- acts as a gate between the left atrium and the left ventricle; the leaflets open/close as the heart beats. 4) Aortic valve- a sophisticated structure that performs a range of functions resulting in the unidirectional flow of blood out of the left ventricle, the optimizing of coronary blood flow, and preservation of myocardial function

Function of coronary arteries

- Deliver blood to the heart muscle providing a continuous supply of oxygen and nutrients needed for it to stay healthy and function normally. - Needs oxygen-rich blood to function. - Also oxygen depleted blood must be carried away. - These arteries wrap around the outside of the heart.

Describe the general structure of cardiac muscle cells:

- Is striated muscle that is present only in the heart. Cardiac muscle fibers have a single nucleus, are branched and joined to one another by intercalated discs that contain gap junctions for depolarization between cells and desmosomes to hold the fibers together when the heart contracts.

Describe the general structure of the Heart:

- The heart is a large muscular pump and is divided in two halves; the right side and the left side. The right side is responsible for pumping deoxygenated blood to the lungs. The left side pumps oxygenated blood around the body. - The heart is divided into four chambers consisting of two atria and two ventricles: the aorta receive blood, while the ventricles pump blood. The right atrium receives blood from the superior and inferior vena cavas and the coronary sinus, blood then moves to the right ventricle where it is pumped to the lungs.

The three primary forms of blood vessels:

1) Arteries 2) Veins 3) Capillaries The three primary forms of blood vessels. Throughout the body, blood vessels pump blood. Blood is transported from the heart by arteries. Back to the heart, the veins return blood. To provide and absorb oxygen, nutrients, and other substances, capillaries surround body cells and tissues.

Overview of Components: Differentiate between the three primary types of blood vessels:

1) Arteries(red) carry oxygen and nutrients away from the heart, to the body's tissues. 2) Veins(blue) take oxygen-poor blood back to the heart. 3) Capillaries are the smallest blood vessels, and they connect arteries to veins.

Compare and contrast the structure and function of these two types:

1) Bicuspid valve (mitral valve) - known as bicuspid because have 2 cusps anterior/posterior; located between the left atrium and the left ventricle (left atrioventricular) orifice. 2) Tricuspid valve- which lies between the two chambers on the right side of the heart; consist of three flaps of tissue called leaflets. Opens when blood flows from the right atrium to the right ventricle.

Distinguish between elastic arteries, muscular arteries, and arterioles:

1) Elastic arteries- largest, conduct blood from heart to smaller arteries, allows arteries to stretch and recoil (aorta, pulmonary trunk) 2) Muscular arteries- medium arteries, deliver blood to specific body regions, better able to vasoconstrict, dilate (brachial, coronary arteries) 3) Arterioles- smallest, vasomotor tone important for blood pressure

Compare and contrast pulmonary circulation and systemic circulation:

1) Pulmonary circulation moves blood between the heart and the lungs. It transport deoxygenated blood to the lungs, to absorb oxygen and release carbon dioxide. The oxygenated blood then flows back to the heart. * carries blood to the lungs for gas exchange and returns it to the heart, pumped from the right side of the heart and returns to left side. 2) Systemic circulation moves blood between the heart and the rest of the body. * carries blood to every organ of the body, pumped from left side of heart and return blood to the right side of the body.

Anatomic structure controlling Heart activity The hearts conduction system This pathway is made up of 5 elements:

1) Sino-atrial (SA) node- electrical stimulus is generated by the sinus node 60 to 100x's per minute under normal conditions. The atria then is activated. The electrical impulse travels down through the conduction pathways and causes the hearts ventricles to contract and pump out blood. The electrical impulses travel from the sinus node to the AV node. 2) Atrioventricular (AV) node- these impulses are slowed down for a very short period, then continue down the conduction pathway via the bundle of HIS into ventricles. The bundle of HIS divides. 3) The Bundle of HIS 4) The left/right bundle branches- into right and left pathways, called bundle branches, to stimulate the left/right ventricles. 5) The Purkinje fibers- then goes to the purkinje fibers, causing the ventricles to contract.

Blood flow from the pulmonary circulation:

1) The right atrium receives- oxygen poor blood from the body and pumps it to the right ventricle through the tricuspid valve. 2) The right ventricle pumps the oxygen-poor blood to the lungs through the pulmonary valve. 3) The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle through the mitral valve. 4) The left ventricle pumps the oxygen-rich blood through the aortic valve out to the rest of the body.

The structure of vessels:

1) Tunica Adventitia or tunica externa- is made up of connective tissue (outer layer) 2) Tunica Media- the middle layer is thicker and contains more contractile tissue in arteries than in veins. It consists of circulatory arranged fibers, connective tissue, and smooth muscle cells. 3) Tunica Intima- inner layer; this layer is made of elastic fiber and collagen. It's consistency varies based on the type of blood vessel.

Explain the distinguishing features of the tunics found in arteries, capillaries, and veins.

1) Tunica intima- inner most layer, simple squamous epithelium 2) Tunica media- middle layer, smooth muscle cells and elastic fibers, vasoconstriction and vasodilation 3) Tunica externa- areolar connective tissue with elastin and collagen fibers, anchors vessel to other structures.

Compare the anatomic structure, function, and location of continuous capillaries, fenestrated capillaries, and sinusoids.

1) continuous capillaries- most common, found in gaps between endothelial cells, (intercellular cleft) 2) fenestrated capillaries- small regions of endothelial cells, have fenestrations. 3) sinusoids- larger openings for things like cells and large proteins (liver).

Trace the movement of blood through a capillary bed:

1) metarteriole 2) metarteriote- connects to thoroughfare channel 3) thoroughfare channel merges with postcapillary venue 4) true capillaries come from thoroughfare channel 5) blood flow through true capillaries regulated by precapillary sphincters shut blood away

Three layers of the pericardium

1. Fibrous pericardium- most superficial layer, made up of dense connective tissue which acts to protect the heart anchoring it to the surrounding walls, and preventing it from over filling with blood. 2. Parietal pericardium- thin inner sac, secretes serous fluid. 3. Visceral pericardium- secretes serous fluid; turns in a base and becomes epicardium. 4) Pericardial cavity- serous fluid inside sac lubricates membranes and allows friction less movement of the heart when it beats. * Pericardial sac encloses the heart.

Layers of the heart wall

1.epicardium- thin serous membrane on surface 2.myocardium- thick cardiac muscle, spiral vortex (contracts with twisting, wringing motion enhancing blood ejection); cells have intercalated disc, where plasma membranes are joined, and electrical gap junctions so contractions as a unit. 3.endocardium- thin interior lining