Cardiovascular System Flashcards
How do lymphatic vessels help the cardiovascular system?
Lymphatic vessels help by collecting excess fluid surrounding tissues and returning it to the cardiovascular system.
Primary function of the Cardiovascular System
Service cells of the body, bringing nutrients to cells and helping to remove waste.
Three Major Components of the Cardiovascular System
Heart
Veins
Arteries
Four Functions of the Cardiovascular System
Generates blood pressure and moves blood
Transport blood
Exchange of nutrients and wastes at the capillaries
Regulates blood flow as needed by the body
Parts of the Closed Circuit Pathway of the Cardiovascular System
Heart -> Arteries -> Arterioles -> Capillaries -> Venules -> Veins
-> Heart again
Arteries
Carry blood away from the heart
3 Layers in the wall of an artery
Thin inner epithelium
Thick smooth muscle layer
Outer connective tissue
Arterioles
Small arteries that regulate blood pressure
Capillaries
Microscopic vessels between arterioles and venules. They form beds of vessels where exchange with body cells (nutrients out, waste materials in) occur, and have a combined large surface area.
Precapillary Sphincters
Control blood flow through a capillary bed. They can shut down a blood capillary, and blood then flows through the shunt (direct pass from arteriole to venular). If closed, blood moves to an area where gas exchange is needed. This might happen if it’s cold outside - directs blood towards center of body instead of extremities.
Veins
Carry blood toward heart. If they carry blood against gravity, they have valves to keep blood flowing toward heart.
Venules
Small veins that receive blood from the capillaries.
3 layers of Venules and Vein walls
Thin inner epithelium
Smooth muscle layer (less than arteries)
Outer connective tissue (less than arteries)
Overall, thinner than arteries, allowing for greater expansion
Heart
Large, muscular organ consisting of mostly cardiac muscle tissue. It runs the cardiovascular system.
Myocardium
The cardiac muscle tissue in the heart.
Cardiac Muscle Fibers
Branched, uninucleated, striated muscle fibers. Tightly joined by intercalated disks.
Intercalated Disks
Disks that hold the cardiac muscle fibers together very tightly so that there is no “leakage” of fluids such as blood.
Pericardium
Sac that surrounds the heart.
The right and left sides of the heart are separated by what?
The septum
Atria
The chambers in the upper half of the heart
Ventricles
The chambers in the lower half of the heart
2 sets of valves in the heart
Atrioventrical
Semilunar
Purpose of heart valves?
Heart valves keep blood flowing in one direction
Atrioventricular Valves are between what?
The atria and the ventricles.
The Left Atrioventricular valve is what?
Bicuspid
The right atrioventricular valve is what?
Tricuspid
Superior Vena Cava
Primary vein returning to the heart from the top of the body.
Inferior Vena Cava
Primary vein returning to the heart from the bottom of the body.
Aorta
Primary artery
Process of blood flow through the heart (LONG!)
Inferior and superior vena cava dump blood into the right atrium. The right ventricle then sends the blood into the pulmonary trunk, where two pulmonary arteries lead the blood to the lungs, where the blood becomes oxygenated via capillaries. The pulmonary veins bring blood from the lungs back to the left atrium. The left ventricle then contracts, pumping blood into the aorta and to the rest of the body. It will then be pumped back to each vena cava.
How does the left ventricle compare to the right ventricle?
The left ventricle is more muscular than the right ventricle because it must pump blood to the entire body.
How do arteries compare to veins?
Arteries are more muscular than veins so as to help them withstand the high pressure exerted on them.
How do veins compare to arteries?
Veins have a thinner wall and a larger center to contain blood, and so are more expandable. About 70% of one’s blood is stored in veins.
Systole
The atria contract together, followed by the ventricles contracting together. This is the first stage of the heartbeat.
Diastole
A rest phase in the heartbeat during which the chambers of the heart relax.
How often does the cardiac cycle, or heartbeat, occur, on average?
70 times per minute
Nodal tissue has what types of characteristics, and does what?
Muscular and nervous characteristics. It is the locus of internal control.
Sinoatrial Node
The sinoatrial node, part of the nodal tissue, is in the right atrium. It initiates the heartbeat and causes the atria to relax.
Atrioventricular Node
The atrioventricular node is in the right atrium, and after the sinoatrial node causes the atria to relax, the atrioventricular node causes the ventricular contraction.
What is the external control of the heartbeat?
A cardiac center in the brain and hormones such as epinephrine and norepinephrine gives the external control of the heartbeat.
What is an electrocardiogram?
An electrocardiogram is the record of the electrical changes in the heart muscle (myocardium) during a cardiac cycle.
P Wave
An electrical current produced by the atria, when it is stimulated by the sinoatrial node.
QRS Complex
The QRS complex is the contraction of the ventricles.
T Wave
The T Wave is the recovery of the ventricles.
Blood Pressure
Pressure against a blood vessel wall, usually measured in an artery of the arm.
Systolic Pressure
The highest pressure, on the top of a blood pressure reading, is during blood ejection from the heart.
Diastolic Pressure
The lowest pressure, on the bottom of the blood pressure reading, occurs when the ventricles relax.
What is the average blood pressure?
120/80 mmHg
What controls one’s blood pressure?
Arterioles
What causes blood flow to increase?
Skeletal Muscle Contraction
Breathing
Valves
Name the 2 Major Cardiovascular Pathways
Pulmonary Circuit
Systemic Circuit
Pulmonary Circuit
Right side of heart reoxygenates the blood by bringing blood from the body to the heart and then to the lungs.
Systemic Circuit
The left side of the heart that sends oxygenated blood to the entire body, delivers nutrients, and rids of waste.
What causes the exchange of capillary beds?
The exchange at capillary beds is primarily a result of osmotic and blood pressure.
Describe the arterial end of the capillary bed.
Blood pressure is higher than osmotic (fluid driven) pressure. The net pressure is out.
Describe the venous end of the capillary beds.
The osmotic pressure (fluid driven pressure) is higher than blood pressure. Net pressure is in.
What lies next to capillary beds?
Lymphatic capillary beds lie alongside capillary beds.
Hypertension
High blood pressure when blood moves through vessels at a rate higher than normal, often due to arterial plaque. Normally, 140/90 mmHg or higher; it is a silent killer as there are few symptoms but it can lead to a heart attack, stroke, or kidney failure.
Atherosclerosis
Build up of plaque in blood vessels. It is associated with strokes, heart attacks, and aneurysm.
Thrombus
Stationary plaque in atherosclerosis
Embolus
Arterial plaque that has detached and can move to distant sites. Associated with atherosclerosis.
Stroke
Cerebrovascular accident; usually occurs when a cranial artery is blocked or bursts. Part of the brain dies due to lack of oxygen.
Heart Attack
Myocardial infarction, when part of the heart dies due to lack of oxygen. It can begin with angina pectoris.
Angina Pectoris
Pain that radiates down one’s left arm due to blockage of the coronary artery.
t-PA
A drug that dissolves blood clots
Three ways of treating clogged arteries
Bypass Surgery
Stents
Angioplasty
Bypass Surgery
Usually a vein from the leg is taken and used to bypass clogged artery.
Stents
A wire mesh cylinder inserted into a clogged artery to hold it open.
Angioplasty
Tube with a balloon is inserted into clogged artery to inflate it.
Aneurysm
A ballooning of a blood vessel. The most commonly affected is the abdominal artery or the arteries leading to the brain. Atherosclerosis and hypertension can weaken a vessel and cause ballooning.
