Module 10: The circulatory system

What is the primary function of the circulatory system related to transportation?

transport nutrients, O2, CO2, waste, and hormones.

How does the circulatory system contribute to defense?

It supports immunity and wound healing.

How does the circulatory system help maintain homeostasis?

It helps regulate body temperature, pH, and water balance.

What are the major organs and tissues involved in the human cardiovascular system?

blood (cells and plasma), the heart, and blood vessels

What is the function of the heart in the cardiovascular system?

to pump blood to drive circulation.

What is the function of arteries in the cardiovascular system?

to carry blood away from the heart.

Systemic arteries carry

oxygenated blood

Pulmonary arteries carry

deoxygenated blood.

What is the function of veins in the cardiovascular system?

to carry blood to the heart

Systemic veins carry

deoxygenated blood.

Pulmonary veins carry

oxygenated blood.

What is the role of capillaries in the cardiovascular system?

to exchange gases, nutrients, and waste with tissues.

What is plasma in blood?

the liquid component of blood in which cellular elements are suspended

What are the cellular elements of blood?

red blood cells (RBCs), white blood cells (WBCs), and platelets.

What are RBCs, and what percentage of blood volume do they make up?

RBCs (erythrocytes) make up 36-50% of blood volume and are responsible for oxygen transport.

What are WBCs?

WBCs (leukocytes) are blood cells involved in the immune response and defense against infections.

What are platelets?

cell fragments that play a key role in blood clotting.

What is the main component of plasma?

water, which makes up 92% of plasma

What percentage of plasma is made up of plasma proteins?

7%

What is the role of plasma in transporting molecules?

transporting fatty acids and steroid hormones.

How does plasma help maintain fluid balance in the blood?

it helps maintain osmotic pressure.

What immune-related function does plasma serve?

it contains antibodies that help in immune defense.

How is plasma involved in blood clotting?

it contains proteins that aid in blood clotting.

What makes up the remaining 1% of plasma?

ions, gases, nutrients, and waste.

Where does hematopoiesis occur?

the red bone marrow

What are all formed elements in blood derived from?

hematopoietic stem cells.

What drives the differentiation of blood cells?

hematopoietic growth factors.

hematopoietic growth factors

a group of proteins that regulate the production, growth, and differentiation of blood cells

What hormone is produced by the kidneys to stimulate red blood cell production?

Erythropoietin

How does the number of erythrocytes compare to leukocytes in a drop of blood?

One drop of blood contains millions of erythrocytes but only thousands of leukocytes.

What percentage of total body cells are erythrocytes?

25% of the total cells in the body.

What is the shape of erythrocytes?

biconcave discs

Do erythrocytes have DNA or organelles?

No, erythrocytes lack DNA and organelles.

What protein do erythrocytes contain in large amounts?

hemoglobin

How do erythrocytes maintain flexibility?

They contain structural proteins that allow for flexibility.

Why is the high surface area to volume ratio important for erythrocytes?

It enhances gas exchange efficiency.

What is anemia?

a condition characterized by a low erythrocyte (red blood cell) count.

What are the main causes of anemia?

can be caused by blood loss, low or faulty red blood cell production.

What genetic disorder leads to abnormal hemoglobin and misshapen erythrocytes?

Sickle cell disease

What nutrient deficiency can lead to anemia due to insufficient hemoglobin production?

Iron deficiency

What deficiencies can cause faulty red blood cell production?

Vitamin deficiencies, such as B12 or folate deficiency,

What is the first step in blood clotting?

blood vessel injury exposes collagen, which triggers platelet activation.

What do platelets do when they encounter exposed collagen?

Platelets adhere to the collagen and form a platelet plug to temporarily seal the injury.

What strengthens the platelet plug into a more stable clot?

A fibrin clot forms, reinforcing the platelet plug with a mesh of fibrin protein.

What process leads to the formation of fibrin?

The enzymatic cascade, also known as the coagulation cascade, activates clotting factors that convert fibrinogen into fibrin.

What is the shape of the heart?

pine cone shaped

How big is the heart?

about the size of a fist and weighs 250-350 grams.

How does an athlete’s heart compare to a non-athlete’s heart?

The heart is larger in athletes due to increased cardiovascular demand.

How many chambers does the heart have?

four chambers: two atria and two ventricles.

What are the names of the four heart chambers?

The left and right atria (upper chambers) and left and right ventricles (lower chambers).

What is cardiac output (CO)?

the amount of blood pumped by each ventricle in one minute.

What is the average cardiac output?

5.25 L/min, which is slightly more than the total blood volume.

What is stroke volume (SV)?

the quantity of blood pumped out of the ventricles per beat and is related to blood pressure.

What is heart rate (HR)?

the number of cardiac cycles (heartbeats) per minute.

What is the formula for cardiac output?

CO = SV × HR (Cardiac Output = Stroke Volume × Heart Rate).

In which direction do substances naturally move?

from high pressure to low pressure.

What is the main driver of blood flow in the body?

Pressure gradients drive blood flow by pushing blood from areas of higher pressure to areas of lower pressure.

How does increased pressure in one area affect blood movement?

Increased pressure in one area forces blood to move to a lower-pressure area.

What is the myocardium?

the muscular layer of the heart responsible for contraction.

What surrounds cardiac muscle cells?

collagenous fibers, blood vessels, and nerve fibers that regulate heart function.

What are the two phases of the cardiac cycle?

systole (contraction) and diastole (relaxation)

systole phase

the phase of the cardiac cycle when the heart contracts, pumping blood out of the ventricles.

diastole phase

the phase of the cardiac cycle when the heart relaxes, allowing the chambers to fill with blood.

Why is the left side of the heart thicker?

because it pumps blood to the entire body, requiring more force.

What are septa in the heart?

extensions of the myocardium that divide the heart's chambers.

What is the function of the interatrial septum?

divides the atria (upper chambers) of the heart.

What is the function of the interventricular septum?

divides the ventricles (lower chambers) of the heart.

What is the role of the atrioventricular septum?

divides the atria from the ventricles.

What are the two types of heart valves?

atrioventricular valves (tricuspid and mitral) and semilunar valves (pulmonary and aortic).

What are the atrioventricular valves?

tricuspid valve (right side) and the mitral (bicuspid) valve (left side).

What are the semilunar valves?

the pulmonary valve (right side) and the aortic valve (left side).

What is the function of heart valves?

prevent the backflow of blood, ensuring it moves in the correct direction.

What is the tricuspid valve, and where is it located?

regulate blood flow within the heart; located between the right atrium and right ventricle of the heart and has three flaps.

What is the mitral (bicuspid) valve, and where is it located?

regulates the flow of blood from the left atrium to the left ventricle and has two flaps.

where does the pulmonary valve direct blood?

from the heart to the lungs, ensuring oxygen-poor blood moves forward and prevents backflow

What is the aortic valve, and where does it direct blood?

controls blood flow from the heart into the body's main artery, ensuring unidirectional flow and preventing backflow

What causes heart sounds?

the closing of the heart valves.

What is sound 1 (lub) in the heart?

the sound made by the AV valves (tricuspid and mitral) closing.

What is sound 2 (dub) in the heart?

the sound made by the semilunar valves (pulmonary and aortic) closing.

What could sounds other than "lub, dub" (murmur) indicate?

sounds such as a murmur, might indicate heart dysfunction.

Why do cardiomyocytes (heart muscle cells) need oxygen?

for energy to contract and function properly.

which arteries supply the heart with oxygen?

coronary arteries

What is the exception to the "A" rule in circulation? (A=away)

The coronary arteries are an exception to the "A" rule (arteries carry oxygen-rich blood) because they carry oxygen-rich blood to the heart, but the coronary veins carry oxygen-poor blood.

What is the coronary sinus, and where does it drain?

it formed by the joining of cardiac veins, and it drains into the right atrium.

What is a myocardial infarction (heart attack)?

the blockage of a coronary artery, usually caused by plaque or a blood clot.

What happens when there is a blockage in the coronary artery?

leads to a lack of oxygen to the heart muscle, causing tissue damage.

What happens to heart cells during a myocardial infarction?

The heart muscle cells die due to lack of oxygen, and scar tissue forms in place of the damaged cells.

What are myocardial contractile cells?

______ make up 99% of the cells in the atria and ventricles and are responsible for pumping blood.

How do myocardial contractile cells compare to skeletal muscle cells?

______ are similar to skeletal muscle cells in structure, but they are specialized for pumping blood.

What are myocardial conducting cells?

cells that trigger the contraction of the heart by generating electrical impulses.

What is the Sinoatrial (SA) node?

a group of specialized cells in the right atrium that initiate the sinus rhythm, setting the electrical pattern that causes heart contraction.

Where is the Atrioventricular (AV) node located, and what is its function?

located in the inferior part of the right atrium and causes a pause in the electrical signal before passing it to the ventricles.

What is the AV bundle (Bundle of His)?

it carries the electrical signal from the AV node to the ventricles and papillary muscles, ensuring coordinated contraction.

What happens to the AV bundle as it moves toward the ventricles?

the _____ splits into bundle branches that transmit the electrical signal to different parts of the ventricles.

What are Purkinje fibers, and what is their role in the heartbeat?

conductive fibers that extend throughout the myocardium, ensuring rapid and synchronized contraction of the ventricles.

What is the Sinoatrial (SA) node, and why is it called the pacemaker?

a group of specialized cells in the right atrium that initiate the sinus rhythm, setting the heart's electrical pattern. It is called the pacemaker because it controls the heartbeat.

How does the electrical signal spread from the SA node?

The electrical signal spreads from the SA node to the atrial myocardial contractile cells and the AV node, leading to atrial contraction.

What is the function of the interatrial band?

to conduct electrical activity from the SA node to the left atrium, ensuring both atria contract together.

What happens when electrical activity reaches the atrial muscle cells?

this triggers muscle contraction, allowing the atria to push blood into the ventricles.

What is the Atrioventricular (AV) node, and what does it do?

a group of specialized cells in the inferior right atrium that causes a brief pause in the electrical signal before sending it to the ventricles.