Chapter 5 Flashcards
What is myocardium?
The thick muscular middle layer of the heart. Contraction of this muscle layer develops the pressure required to pump blood through the blood vessels.
What is endocardium?
Inner layer of the heart, lining the heart chambers. It is very smooth, thin layer that serves to reduce friction as the blood passes through the heart chambers.
What is epicardium?
The outer layer of the heart.
What is the pericardium?
The double layered pleural sac where the heart is enclosed.
The heart is divided into what?
4 chambers or cavities. Two atria and two ventricles
The right and left side are decided by what?
Walls called the Interatrial septum and the interventricle septum
The atria are what?
The receiving chambers
The ventricles are?
The pumping chambers
Cardiovascular system is also called what?
The circulatory system which maintains the distribution of blood throughout the body and is composed of the heart and blood vessels- arteries, capillaries and veins.
The circulatory system is composed of what two parts?
The pulmonary and systemic
What is pulmonary circulation?
It transports deoxygenated blood between the heart to the lungs
What is systemic circulation?
Carries oxygenated blood away from the heart to the tissues and cells, then back to the heart.
What is the apex of the heart?
Tip at the lower edge
What part of the heart has a thicker myocardium and why?
The ventricles so they can eject blood out of the heart and into the great arteries
What do the 4 valves of the heart do?
Act as a restraining gate to control the direction of blood flow.
What is the tricuspid valve?
An atrioventricular valve meaning it controls the opening between the right atrium and the right ventricle. Once blood enters the right ventricle it can not go back up to the atrium. The prefix tri means 3 indicates this valve has 3 leaflets or cusps
What is the Pulmonary valve?
A semilunar valve, semi meaning half and lunar meaning moon. Indicates this is a half moon shape. Located between the right ventricle and the pulmonary artery. This valve prevents blood to go back into the right ventricle
What is the mitral valve?
Also known as the bicuspid valve, indicating it has two cusps, it is an atrioventricular valve from the left atrium to the left ventricle, this prevents blood to flow back up to the left atrium
What is the aortic valve?
A semilunar valve located between the left ventricle and the aorta, prevents blood flow to go back into the left ventricle
How does blood flow through the heart (6 steps)?
- Deoxygenated blood from all the tissue in the body flow into the right atrium through two large veins called the Superior vena cava and the inferior vena cava
- Right atrium contracts and blood flows through the tricuspid valve into relaxed right ventricle
- The right ventricle then contracts and blood is pumped through the pulmonary valve to the pulmonary artery, which carries it to the lungs for oxygenation
- The left atrium receives the blood returning to the heart after oxygenation, this blood enters from the 4 pulmonary veins.
- The left atrium contract and blood flows through the mitral valve to the relaxed left ventricle.
- When the left ventricle contracts the blood is pumped through the aortic valve and into the aorta which carries it to all parts of the body.
What is the largest artery in the body?
The aorta
Why do the heart chambers alternate between relaxing?
In order to push blood forward
What is diastole?
The period of time a chamber relaxes
What is systole?
A period of time a chamber contracts
The heart rate is regulated by what?
The autonomic nervous system because we have no control over the beating of our heart
What is the Sinatrial (SA) node?
The pacemaker, where the electrical impulses begin, from the SA a wave of electricity travels through the atria causing them to contract or go into systole
What is responsible for conducting an electrical impulse through the different chambers?
Special tissue
In what 5 steps do electrical impulses travel through the heart?
- The SA or pace maker through the atria
- The atrioventricular node is stimulated
- This node transfers the stimulation to atrioventricular bundle ( formerly called the bundle of His)
- Electrical signal travels down the bundle branches within the interventricle septum
- The purkinje fibers out in the ventricle myocardium are stimulated. Resulting in ventricle systole.
What are the three types of blood vessels?
Arteries, capillaries and veins