MT M 5.1 Cardiovascular system intro Flashcards
cardiovascular system
The cardiovascular system consists of the heart and blood vessels that transport blood throughout the body. Cardi/o is a combining form that means the heart. Vascul/o is a combining form that means small vessel.
circulatory system
The heart and the blood vessels of the body provide the cells of the body with nutrients and oxygen and provides a way for waste and carbon dioxide to be removed from the cell. This system is also called the circulatory system because the blood is moved through the body in a circle by the pumping action of the heart.
Cardiology
Cardiology is the specialty of medicine that involves the study of the heart and blood vessels. It is a subspecialty of internal medicine.
cardiologist
A cardiologist is a physician that specializes in the study of the heart, blood vessels, and treatment of disorders of the heart and blood vessels.
cardiovascular surgeon
A cardiovascular surgeon is a physician that is trained to operate on the heart, lungs, and blood vessels.
heart
The heart and the blood vessels make up the main structures of the cardiovascular system. Figure 5.1 shows an overview of the cardiovascular system. The heart is a muscular pump and the central organ of the cardiovascular system. The heart pumps continually throughout an individual’s lifetime. It is about the size of an adult fist, and it pumps approximately 100,000 times a day. The heart receives blood from the body, pumps that blood to the lungs to receive oxygen and at the same time, it receives oxygenated blood from the lungs and pumps that blood out to the body tissues.
mediastinum
The mediastinum is the space between the pleural cavities, and it contains the organs between the pleural cavities.
heart 2
The heart is a hollow, muscular organ that is in the thoracic cavity, specifically, in the pericardial cavity. This space is also called the mediastinum.
heart has three layers
The heart has three layers called the endocardium, the myocardium, and the pericardium.
myocardium
The myocardium is the muscular, middle layer of the heart.
endocardium
The endocardium is the inner lining of the heart.
pericardium
The pericardium is the outer sac that surrounds the heart and decreases friction between the heart and the other structures around it.
heart is divided into two sides
The heart is divided into two sides: the right side and the left side of the heart.
left side of the heart
The left side of the heart pumps blood from the lungs to the body tissues.
right side of the heart
The right side of the heart pumps blood from the body tissues to the lungs.
septum
The sides of the heart are divided by a partition called a septum. Each side of the heart consists of two chambers: an atrium and a ventricle.
right atrium (RA)
The right upper portion of the heart is the right atrium (RA). Two large veins, the superior vena cava and the inferior vena cava, bring blood from the body to the right atrium.
right ventricle (RV)
The right lower portion of the heart is the right ventricle (RV). It receives the blood from the right atrium and pumps it into the pulmonary trunk and the right and left pulmonary arteries.
left ventricle (LV)
The left lower portion of the heart is the left ventricle (LV). It receives blood from the left atrium and pumps it out to the large artery, the aorta.
left atrium (LA)
The left upper portion of the heart is the left atrium (LA). It receives blood from the right and left pulmonary veins.
There are four valves that separate the four chambers of ther heart
They are located at the entrance and exit of each ventricle and control the flow of blood from one area of the heart to another.
tricuspid valve
the four chambers of ther heart
The tricuspid valve is located between the right atria and the right ventricle.
pulmonary valve
the four chambers of ther heart
The pulmonary valve is located at the exit of the right ventricle and controls the flow of blood from the right ventricle to the pulmonary trunk.
mitral valve
the four chambers of ther heart
The mitral valve is located between the left atrium and the left ventricle. The mitral valve is also known as the bicuspid valve.
aortic valve
the four chambers of ther heart
The aortic valve is located at the exit of the left ventricle and controls the flow of blood from the left ventricle to the aorta.
Blood Circulation
The circulation of blood through the body starts and ends at the heart.
1) Starting with the right side of the heart, blood enters the heart from the body tissues via the superior and inferior vena cava. These are large veins that drain all the blood from the upper and lower body into the right atrium.
2) It travels through the tricuspid valve
3) into the right ventricle. Blood leaves the right side of the heart through
4) the pulmonary valve and into the right and left pulmonary arteries and to the lungs for oxygenation. The right and left pulmonary arteries are the only arteries in the body that carry deoxygenated blood. Oxygenated blood is removed from the lungs via the right and left pulmonary veins, the only veins in the body to carry oxygenated blood.
5) The right and left pulmonary veins enter the left side of the heart at the left atrium. The blood travels through
6) the mitral valve into
7) the left ventricle. The blood leaves the heart through
8) the aortic valve and enters the aorta. From the aorta, blood is dispersed to the body tissues.
Arteries
Arteries are blood vessels that carry blood away from the heart to the body tissues. The arteries of the body are a network of progressively smaller vessels that eventually become arterioles.
Arterioles
Arterioles are the smallest arteries, only consisting of one to two cell layers of muscle cells, that are continuous with the capillary bed.
The capillary bed
The capillary bed consists of microscopic blood vessels where oxygen and nutrients are delivered to the cells of the body and carbon dioxide and other waste products are removed from the cells of the body. The capillary bed connects the arterioles to the venules.
Venules
Venules are the smallest veins, again one to two muscle cell layers thick, and they connect with successively larger veins.
Veins
Veins are the blood vessels that return the blood to the heart
heartbeat
The heartbeat is a coordinated contraction of the heart. The heart begins to beat, or contract, 5-6 weeks after conception. It beats continuously throughout a person’s lifetime and ceases at the time of death. The heartbeat is controlled by the autonomic nervous system.
neuromuscular
There is special neuromuscular tissue in the heart that stimulates the heart muscle to contract continuously and rhythmically.
sinoatrial node (SA node)
The pacemaker of the heart is the sinoatrial node (SA node). It is a dense collection of Purkinje fibers located in the upper part of the right atrium. This is where the heartbeat initiates. An electrical impulse starts in the SA node and travels through the internodal pathway throughout the atria and stimulates the atria to contract.This impulse then reaches the atrioventricular node (AV node)
atrioventricular node (AV node)
An electrical impulse starts in the SA node (#1 on Figure 5.5) and travels through the internodal pathway throughout the atria and stimulates the atria to contract. This impulse then reaches the atrioventricular node (AV node) (#2 on Figure 5.5) and travels to the atrioventricular bundle, also called the bundle of His (#3 on Figure 5.5). The bundle of His branches into two bundle branches (#4 on Figure 5.5) that travel down the interventricular septum. These bundles transmit the electrical signal through Purkinje fibers throughout the ventricles (#5 on Figure 5.5), stimulating contraction of the ventricles.
electrocardiogram (ECG or EKG)
The electrical activity of the heart is measured with an electrocardiogram (ECG or EKG). This diagnostic tool can be used to detect abnormalities in the heart, such as ischemia or arrhythmias.
Pulses and Blood Pressure
The walls of the arteries are elastic and as the heart pumps blood, they move in a pulsating wave to push the blood through the vessel. This pulse of the artery wall can be measured to detect the rate and rhythm of the heart, as well as monitor circulation. All arteries have a pulse. However, there are common sites in the body where the pulse is more easily detected because the artery can be compressed against a bone.
radial pulse
The most common site to measure the pulse is the radial pulse. This is located on the thumb side of the wrist.
dorsalis pedis pulse
The dorsalis pedis pulse on the dorsal surface of the foot is used to assess peripheral artery disease.
carotid pulse
The carotid pulse in the neck is the easiest pulse to palpate and is commonly used in an emergency.
pulse is taken
When the pulse is taken, the pulsations are counted and then reported in a measurement of beats per minute (BPM). A normal pulse is 60-100 BPM.
Blood pressure measurment
As the cuff inflates and pressure on the brachial artery increases, the technician will not be able to hear the pulse through the stethoscope because the artery is closed. As the release valve is loosened, and the cuff begins to deflate slowly, the artery will open, and the pulse will be heard. The pressure where the pulse can be heard is the systolic pressure measurement. The pulse can be heard for a few seconds as the pressure continues to decrease, and then the technician will be unable to hear the pulse anymore because the artery is fully open. The pressure where the pulse is no longer able to be heard is the diastolic pressure measurement.
Blood pressure
Blood pressure is the measurement of the pressure that the blood is exerting against the arterial wall as the heart pumps and the resistant force of the arterial wall against that blood flow. This measurement is always reported in two measurements of millimeters of mercury (mmHg)
sphygmomanometer
This measurement is taken with a sphygmomanometer. Figure 5.10 shows a sphygmomanometer taking a blood pressure measurement.
Systolic blood pressure
Systolic blood pressure is the measurement of the pressure when the heart contracts and the blood is pumped to the body.
Diastolic blood pressure
Diastolic blood pressure is the measurement of the pressure when the heart is relaxed. The blood pressure measurement is always reported as the systolic pressure first and the diastolic pressure second. A normal blood pressure is less than 120/80 mmHg.
