Circulatory System Review

Comprehensive review flashcards covering key terms, functions, blood components, circulation circuits, cardiac anatomy and conduction, blood vessels, intersystem interactions, and cardiovascular diseases.

What is another name for the circulatory system?

The cardiovascular system.

What is the primary difference in function between an artery and a vein?

Arteries carry blood away from the heart, whereas veins carry blood back to the heart.

What are capillaries and what is their role in the circulatory system?

Capillaries are the smallest blood vessels found between arteries and veins whose thin walls allow oxygen, nutrients, carbon dioxide, and waste products to pass to and from tissue cells.

What are the four major functions of the cardiovascular system?

Transportation of nutrients, oxygen, and waste products; protection from infection; regulating body temperature (thermoregulation); and maintaining fluid balance in the body.

How does the circulatory system respond when body temperature becomes too high?

Smooth muscles in the walls of arteries are stimulated to relax, causing vasodilation (an increase in vessel diameter), which increases blood flow to the skin to allow cooling to occur.

How does the circulatory system respond when body temperature becomes too low?

Smooth muscles of arteriole walls cause vasoconstriction (reducing vessel diameter), decreasing blood flow to the skin to help maintain core body temperature.

Which organs and sensory structures detect changes in fluid levels to regulate fluid balance in the body?

Kidneys and osmoregulators.

What percentage of blood volume is made up of plasma, red blood cells, white blood cells, and platelets?

Plasma makes up $55\%$, red blood cells make up $41\%$, white blood cells make up $3\%$, and platelets make up $1\%$.

What is plasma and what is its role in the blood?

Plasma is the yellowish, liquid portion of blood made mostly of water, along with proteins, sugars, hormones, and salts; it transports water and nutrients to the body's tissues.

What protein gives red blood cells their color and what is its function?

Hemoglobin, which carries oxygen from the lungs to the rest of the body and returns carbon dioxide from the body to the lungs to be exhaled.

What specific roles do neutrophils, T lymphocytes, and B lymphocytes play in protecting the body?

Neutrophils kill and digest bacteria; T lymphocytes directly attack various infected cells; and B lymphocytes produce antibodies that target bacteria and viruses.

How do platelets help stop bleeding at an injury site?

They gather at the site of an injury, stick to the lining of the injured blood vessel, and form a clot (scab) that covers the wound and prevents blood leakage.

What is thrombocytopenia and what major symptom does it cause?

A condition where people do not have enough platelets in their blood, causing them to lose a lot of blood when injured because they cannot form clots effectively.

What are the two major circulation loops in the human body?

The pulmonary (lung) circuit and the systemic (body) circuit.

What occurs during gas exchange in the pulmonary circuit?

Oxygen travels from tiny air sacs in the lungs (alveoli) through capillary walls into the blood, while carbon dioxide passes from the blood into the air sacs to be exhaled.

What are the four chambers of the human heart and their functions?

Two upper chambers (the right and left atria) that receive incoming blood, and two lower chambers (the right and left ventricles) that pump blood out of the heart.

What type of muscle makes up the heart, and what is the heart's average size?

The heart is made of cardiac muscle and is about the size of a person's fist.

How much blood does the average heart pump each day?

About $2000\text{ gallons}$ of blood per day.

What are heart valves and what is their function?

Valves are flaps between sections of the heart that open and close when the heart beats to prevent blood from traveling backward.

Why do the left atrium and left ventricle appear on the right side of heart diagrams?

Diagrams show what the heart looks like when looking straight at a person, meaning their left side corresponds to your right.

What path does oxygen-poor blood take through the right side of the heart?

Blood enters through the vena cava into the right atrium, passes through the tricuspid valve into the right ventricle, and is pumped past the pulmonary valve through the pulmonary artery to the lungs.

What path does oxygen-rich blood take through the left side of the heart?

Blood from the lungs enters via pulmonary veins into the left atrium, passes through the mitral valve into the left ventricle, and is pumped past the aortic valve through the aorta to the body.

Which valve is located between the right atrium and the right ventricle?

The tricuspid valve.

Which valve is located between the left atrium and the left ventricle?

The mitral valve.

How is the electrical signal that coordinates a heartbeat transmitted through the heart?

The signal starts at the sinoatrial (SA) node and triggers the atria to contract, reaches the atrioventricular (AV) node where it briefly slows down, and then triggers the ventricles to contract.

What is the normal resting heart rate for a human?

Between $60$ and $100\text{ beats per minute}$.

What does an electrocardiogram (EKG) measure?

Electrical signals in the heart.

What is Sick Sinus Syndrome and what is a common symptom?

A group of diseases that affect the sinoatrial (SA) node, often causing an irregular heartbeat.

What is the total approximate length of the human blood vessel network?

Over $60{,}000\text{ miles}$ long.

Why do veins appear blue under the skin if blood is always red?

Blood is always red, but veins appear blue because red and blue light have different wavelengths that penetrate the skin differently, causing our eyes to perceive veins as blue.

How does the skeletal system interact with the circulatory system?

Bone marrow within bones contains stem cells that mature into distinct blood cells: red blood cells, white blood cells, and platelets.

What is atherosclerosis?

The thickening or hardening of arteries caused by a buildup of plaque in their inner lining.

What is the medical term for a heart attack, and what causes it?

Myocardial infarction; it occurs when heart muscle begins to die because of a lack of blood flow caused by a blockage in the arteries supplying the heart.

What is a stroke and what causes brain cells to die during one?

A disease affecting arteries leading to and within the brain, where a blood vessel is blocked by a clot or ruptures, depriving brain cells of oxygen and blood.

What is hypertension and what serious health complications can it lead to?

High blood pressure (consistently excessive force of blood flowing through vessels), which can lead to stroke, loss of vision, heart failure, heart attack, and kidney disease.