Lecture 9 2/25/14 Flashcards
The Heart
Hollow muscular organ, that pumps blood through the circulatory system.
Situated obliquely within the mediastinum and the lowest part is the left 5th lowest intercostal space within the apex.
The wider base is at the top and is the right 2nd intercostal space. 2/3 of the mass of the heart is to the left and 1/3 of the mass is to the right. Located in the front of the trachea and the esophagus.
The Heart Produces what?
ANH or ANP
Atrial Natriuretic Hormone or Atrial Natriuretic Peptide
Describe the Vessels?
are rigid pipes, so if we increase our fluid volume, we will see a corresponding increase in blood pressure.
Pericardium
Loose Fitting Membrane, enclosing the heart
3 Functions of the Pericardium
- It serves to protect the heart.
- It helps reduce the friction between the heart and non-moveable structure. So any structure that moves in the thoracic cavity, it has a membrane that produces serrous fluid that helps reduce friction between the two moving components.
- Bind the heart into the proper position to prevent kinking of the great vessels. Restrict range of motion to a certain extent. Pumps and twists a little bit so the pericardium is bound along the top of the base. The base where the vessels enter and exit, they restrict too much range of motion to heart as it is contracting.
Layers of the Heart
Outside of the Heart:
Parietal Pericardium
Describe Parietal Pericardium
Produce it’s serrous fluid into the space called the Pericardial Cavity or Space.
Black thicker layer, on top of the Parietal Pericardium layer, is called the Fibrous CT layer. Has connective tissue in it. And for the most part it is collagen fiber.
What makes up the Pericardial Sac?
made up of parietal pericardium and the fibrous connective tissue layer. So it’s outer fibrous and inner parietal pericardium.
Pericardial Sac is bound to what?
Bound to the diaphragm and helps to anchor it.
Visceral Pericardium
Adheres to the outside of the heart muscle tissue. Inside layer but outside the heart.
Serrous membrane that comes into contact with the heart, layer that comes into contact on the inside. Same is Epicardium.
Why is it called the Epicardium?
Because the visceral pericardium is bound to the muscular layer of the heart muscle tissue. It is truly the outside layer of the heart.
Both the layers, Visceral Pericardium and Parietal Pericardium are serrous layers that do what?
producing a fluid, serrous fluid, that help lubricate and reduct friction between those two layers.
3 Layers of the Heart
Outer Layer Epidcardium
Middle Layer Mycardium
Inner Layer Endocardium
Describe Epicardium
It is the outer layer
Mycocardium
Middle Layer
The thickest layer. Muscular layer. Contains cardiac muscle, doesn’t contain skeletal muscle. Cardiac muscle and smooth muscle is different from Skeletal muscle because it is a Functional Syncytium, group of muscle fibers that contract as a unit.
Why does Syncytium Happen?
Because of Intercalated Discs. The intercalated discs are gap junctions. Gap junctions conduct electrical impulse, but, they have little portals, or openings between cells, or holes that connect one cell to the next.
Endocardium
Is a endothelial layer. Like the epithelium, but it doesn’t come into contact with the outside environment, if it does, it means you’re bleeding.
It is one cell layer thick and it functions to reduce friction and prevent adhesion of blood products to it’s wall.
Lines the inside the chambers of the heart.
Explain the Blood Flow
From the Superior Vena Cava, the blood flows into the Right Atrium. From the Right Atrium the blood travels down to the Right Ventricle. Then from the Right Ventricle to the Pulmonary Trunk then to the Lungs.
We receive the blood from the lower part of the body, from the Superior and Inferior Vena Cava, we’ve given off the oxygen because we’re coming back from the body to the heart, so we gotta re-oxygenate the blood, so it’s gotta be sent to the lungs.
Now the blood is oxygenated, the flow goes from the lungs, to the Pulmonary Veins going back to the heart to the Left Atrium, then to the Left Ventricle. From the Left Ventricle, the blood leaves to the Aorta.
Two Types of Valves
AV Valves: Atrioventricular Valves. They lie between the atria and the ventricles.
Tricuspid Valve and Bicuspid Valve
Pulmonary Semilunar Valve
Tricuspid Valve
Called Tricuspid Vale because it has 3 flaps to that valve
Pulmonary Semilunar Valve
Next valve going to the lungs; lung circulation
Bicuspid Valve
Blood coming back from the lungs;
It has 2 flaps to that valve. Most common valve for disease, also called Mitral Valve.
Describe the difference between Heart Murmur and Heart Arrhythmia
Heart Murmur is abnormal heart sound
Heart Arrhythmia is a abnormal heart beat
