TEAS Cardiovascular or Circulatory system

What is the responsibility of the cardiovascular or circulatory system?

It is responsible for the movement of blood around the body.

• allows for nutrient distribution and waste removal

• transports nutrients, hormones, and waste

What is the heart made up of?

Cardiac muscle

How many chambers is the heart split into?

Four (4):

• Two atria (right and left atrium)

• Two ventricle (right and left ventricle)

What are the UPPER chambers of the heart called?

Atria

What are the LOWER chambers of the heart called?

ventricles

Right atrium (deoxygenated)

Receives deoxygenated blood from the body

Left atrium (oxygenated)

Receives oxygenated blood from the lungs

Right ventricle (deoxygenated)

Pumps blood to the lungs via the pulmonary loop

Left ventricle (oxygenated)

Pumps blood to the rest of the body via the systemic loop

What are the atria and ventricles attached to?

Veins and arteries that are connected to different parts of the body

How many circulatory systems are there?

Two (2) well-integrated circulatory systems: Pulmonary Circuit (Loop) and Systemic Circuit (Loop).

Pulmonary Circuit (Loop)

Carries deoxygenated blood from the heart (right ventricle) to the lungs to pick up oxygen and drop off carbon dioxide, then returns oxygenated blood to the heart (left atrium).

Systemic circuit (Loop)

Carries oxygenated blood from the heart (left ventricle) to the rest of the body's tissues and returns deoxygenated blood back to the heart (right atrium).

What are the components and structural features of a closed circulatory system?

It is a double-loop system made of three vessel types: arteries, veins, and capillaries.

Arteries

Thick-walled vessels that transport blood away from the heart.

Veins

Thinner-walled vessels that transport blood to the heart.

Capillaries

Made of a single layer of endothelium; form a network connecting arteries to veins in tissues.

What does the closed, double-loop system transport?

Blood and hormones

How many parts does the closed, double-loop system has?

Two (2): pulmonary and systemic

Open lymphatic system

Circulates and filters interstitial fluid between cells and eventually drains into the circulatory system.

Cardiac muscle

Involuntary muscle found in the heart cardiovascular system.

• the system comprised of the heart and blood vessels

Hormone

A chemical messenger produced by a gland and transported by the bloodstream that regulates specific processes in the body.

Tissue

A group of cells with similar structure that function together as a unit, but at a lower level than organs.

How many cycles of contraction does the heart undergo?

Two (2): systole and diastole.

Systole

Contraction of heart muscle (expelling blood)

Diastole

Relaxation of heart muscle (filling with blood).

What is the sound of the heart called?

Lub-dub

How is LUB sound of the heart produced?

When the ventricles contract (ventricular systole), causing the atrioventricular valves—which include the mitral and tricuspid valves—to close.

How is DUB sound of the heart produced?

When the semilunar valves in the aorta and pulmonary trunk close—preventing blood from falling back into the ventricles—as the ventricles relax.

What are the contractions that produce the “lub-dub” sound controlled by?

A pacemaker called the “sinoatrial node.”

Pacemaker

The sinoatrial (SA) node initiates electrical signals.

What does the sinoatrial node do?

Sends out electrical signals

Relaxation

Release of tension in a muscle

Why do arteries have thick walls?

To withstand the pressure of blood pumped by the heart.

How is the constitution of vein walls?

They have a thinner muscle layer and larger lumen.

What does blood plasma contain?

Nutrients, hormones, antibodies, and other immune proteins.

Plasma

Clear pale yellow component of blood that carries red blood cells, white blood cells, and platelets throughout the body.

What do red blood cells (erythrocytes) contain?

Hemoglobin

Hemoglobin

Protein in red blood cells that carries oxygen from the lungs to the rest of the body.

• transport some of the carbon dioxide back to the lungs for removal

What is carbon dioxide used for?

• About 5 to 7% of carbon dioxide is dissolved in plasma

• 85% is used to maintain acid-base or pH balance in the blood through the bicarbonate buffer system

Buffer

• Composition: A solution of a weak acid and its conjugate base (or a weak base and its conjugate acid).

• Function: Resists drastic changes in pH to maintain the proper pH of the body.

How are white blood cells divided into main lineages, and what are they?

Based on the presence of granules in their cytoplasm:

1. Granulocytes: Neutrophils, Eosinophils, Basophils

2. Agranulocytes: Monocytes, Lymphocytes

Lymphocyte

A category of white blood cells that includes natural killer cells, B-cells, helper T-cells, and cytotoxic T-cells.

What do white blood cells do?

Defend against pathogens

Platelets

Cells in the blood responsible for blood clotting

What is the primary function of blood capillaries in the circulatory system?

To allow the exchange of gases (oxygen/CO2), nutrients, and wastes between the blood and the surrounding tissue cells via diffusion.

Which system drains excess interstitial fluid, filters it through lymph nodes, and provides immune surveillance?

The lymphatic system (using lymphatic capillaries to collect fluid and lymph nodes containing lymphocytes and macrophages).

Lymph

Clear fluid that moves throughout the lymphatic system to fight disease

What does lymph do?

Lymph (essentially plasma with the red blood cells removed), eventually drains into the large veins leading back to the heart.

Macrophage

A large white blood cell that ingests foreign material

What are leukocytes and lymphocytes enriched in?

Lymph nodes

• where they monitor and respond to foreign molecules washed into the system.

Leukocyte

White blood cells, which protect the body against disease.

What causes a heart attack, and what are its primary effects on the heart?

• Cause: Blood flow to part of the heart muscle is blocked (circulatory/plumbing issue).

• Effects:

  • Heart tissue is starved of oxygen and gets damaged or dies.

  • Can cause arrhythmias if electrical tissue is damaged.

Stroke

When blood flow to a part of the brain is interrupted or reduced, depriving brain tissue of oxygen and nutrients.

• circulatory emergency affecting the CNS.

• Categorized as ischemic (cause by a blood clot blocking an artery)

• Or hemorrhagic (caused by a ruptured blood vessel)

What is an aneurysm, and where do they most commonly occur?

• Definition: Localized ballooning or dilation of a blood vessel wall due to a weakened arterial wall.

• Common Locations (High-Pressure Vessels):

  • The aorta (abdominal or thoracic)

  • Arteries in the brain (cerebral)

What is atherosclerosis, and what major conditions does it underlie?

• Definition: Buildup of plaque (fats, cholesterol) inside arteries, narrowing the lumen and restricting blood flow.

• Major Conditions Caused:

  • Heart attacks (via coronary artery disease)

  • Ischemic strokes (via carotid artery disease)

Lumen

The inside space or opening of a tubular structure, such as an artery, vein, intestine, or duct.

Ex. Hollow center of a drinking straw through which fluid floods

Coronary artery

• Wrapped around the outside of the heart

• Feed oxygen directly to the heart muscle

• If blocked, causes a heart attack (myocardial infarction)

What is the function of the carotid arteries, and what pathology occurs if they become blocked?

• Function: Run up both sides of the neck to deliver oxygen-rich blood from the heart to the brain and head.

• Pathology: Plaque buildup or a dislodged clot cuts off blood flow, causing an ischemic stroke.

Arrhythmia

Irregular, too fast or too slow heartbeat, caused by a disruption in the heart’s electrical conduction system.

• this is is an electrical problem

Ex. Bradycardia (too slow <60 bpm) or tachycardia (too fast >100 bpm)

Primary pacemaker of the heart

• Sinoatrial (SA) node (located in the right atrium)

• Generates the electrical impulse that sets the heart rate.

• Malfunction of the SA node leads to arrythmias

Hypertension (HTN)

Chronically high blood pressure (the silent killer). Often has zero symptoms until damage is done.

• standard cutoff: 130/80 mmHg or higher

• Forces the heart to work harder to pump blood

• Serves as the primary modifiable risk factor for heart attacks, strokes, and aneurysms.

What causes hypertension?

Increased peripheral resistance— usually caused by narrow blood vessel lumens (from atherosclerosis or vasoconstriction).

• the heart’s left ventricle must pump with much more force, thickening the heart muscle over time.

Why is hypertension dangerous?

Chronic high pressure damages the tunica intimate (inner vessel lining)

Leads to:

• Atherosclerosis (plaque builds up on the damaged walls)

• Aneurysms (weakened walls balloon out

• Strokes & heart attack (vessels burst or get blocked)

How does blood flow throughout the cardiovascular system?

In a cyclic pattern

When it comes to blood flow through the cardiovascular system, what starts in the left ventricle?

Oxygenated blood is pumped to the body

What happens as blood flows through arteries to capillaries?

It transports oxygen to tissues and picks up carbon dioxide.

What happens to the deoxygenated blood?

It reruns to the heart through veins (This blood is now deoxygenated and concentrated with carbon dioxide)

What is the pathway of deoxygenated blood through the heart and lungs?

• Enters: Right atrium → Right ventricle.

• Pumped: Out through pulmonary arteries to the lungs (picks up O2​, drops off CO2​).

• Returns: Via veins to the left atrium to start the cycle over.

Arteries vs. Veins Structural Differences

• Arteries: Have thick, muscular walls (thick tunica media) to withstand massive, high-pressure blood pumped from the heart. They do not have valves.

• Veins: Have thin walls because they are low-pressure systems. They require one-way valves to prevent blood from pooling backward due to gravity as it climbs back to the heart.

How is the composition of capillaries?

The smallest vessels. Their walls are only one cell layer thick (tunica intima only), which is a structural adaptation that allows rapid diffusion of oxygen, nutrients, and waste between blood and tissues.

What are the Atrioventricular (AV) valves and where are they located?

Location: Valves located between the atria and ventricles.

Function: They prevent backflow into the atria during ventricular contraction.

Inclusions: They include the Tricuspid (right side) and Bicuspid/Mitral (left side).

What is the function and location of the Tricuspid valve?

Location: Located between the right atrium and right ventricle.

Function: It prevents deoxygenated blood from flowing back into the right atrium.

What is the function and location of the Bicuspid (Mitral) valve?

Location: Between the left atrium and left ventricle.

Function: It prevents oxygenated blood from flowing back into the left atrium.

What are the Semilunar (SL) valves and where are they located?

Location: Valves located between the ventricles and the major arteries leaving the heart.

Function: They prevent backflow into the ventricles.

Inclusions: They include the Pulmonary and Aortic valves.

What is the function and location of the Pulmonary valve?

Location: between the right ventricle and the pulmonary artery.

Function: It prevents blood from flowing back into the right ventricle after it is pumped to the lungs.

What is the function and location of the Aortic valve?

Location: between the left ventricle and the aorta.

Function: It prevents blood from flowing back into the left ventricle after it is pumped to the body.

What is the Vena Cava and what is its primary role?

The largest vein in the body.

Function: Its primary role is to return deoxygenated blood from the body tissues to the right atrium of the heart.

Superior vena cava

Returns deoxygenated blood from the upper body (head, neck, arms).

Inferior vena cava

Returns deoxygenated blood from the lower body (abdomen, pelvis, legs).