Cardiovascular System Overview

Study Notes

The cardiovascular system comprises the heart, blood vessels, and blood
Cardiovascular pertains to the heart and blood vessels
Combining forms:
- cardi/o - heart
- vascul/o - blood vessels
- -ar - pertaining to

Heart: Receives blood from veins, pumps blood to arteries.
Blood Vessels (arteries): Transport blood away from the heart to all body parts
Capillaries: Permit nutrient and waste product exchange between blood and cells.
Blood Vessels (veins): Return blood from body parts back to the heart.
Blood: Transports oxygen and nutrients to cells, carries away waste.

Blood is a fluid tissue that delivers oxygen and nutrients to body tissues
Blood returns waste products to the kidneys and carries carbon dioxide to the lungs

The heart is a hollow, muscular organ located in the thoracic cavity, between the lungs.
It serves as a powerful pump maintaining blood flow throughout the entire body.
The apex is the lower tip of the heart.

Heart walls consist of three layers: epicardium, myocardium, and endocardium
The epicardium is the outer layer
The myocardium is the middle, thickest layer, consisting of specialized cardiac muscle for constant contraction and relaxation, essential for blood flow throughout the body.
The endocardium forms the inner lining of the heart, interacting directly with blood during pumping

The myocardium, constantly beating, needs a constant oxygen and nutrient supply and waste removal.
Coronary arteries supply oxygenated blood to the myocardium (depicted in red).
Veins (depicted in blue) remove waste products from the myocardium.

The heartbeat involves the coordinated contraction and relaxation of heart chambers.
The heart's rhythm is regulated by electrical impulses originating from nerves that stimulate the myocardium of the heart chambers.

Heart rate (pulse): Number of times the heart beats per minute.
Factors impacting heart rate include physical activity, emotions, and medications.
Blood pressure: Force of blood against artery walls.
Blood pressure values assess cardiovascular health.
Conditions like hypertension (high blood pressure) or hypotension (low blood pressure) are indicated by blood pressure values.
Systolic pressure: Highest pressure during ventricular contraction.
Diastolic pressure: Lowest pressure during ventricular relaxation.

Blood is composed of 55% plasma (straw-colored fluid) and 45% formed elements.
Plasma comprises 91% water; the remaining 9% consists mainly of proteins, including clotting proteins
Nutrients, hormones and waste products are part of the plasma.

Formed elements include erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets).
Erythrocytes (RBCs): Mature red blood cells, produced in red bone marrow, transport oxygen using hemoglobin.
Leukocytes (WBCs): Defend the body against pathogens (bacteria, viruses, and fungi); further subdivided into 5 major types (neutrophils, basophils, eosinophils, lymphocytes, monocytes).
Thrombocytes (platelets): Smallest formed elements of blood, crucial for blood clotting.

Cardiologist: Diagnoses and treats heart disorders.
Hematologist: Diagnoses and treats blood and blood-forming tissue disorders.
Vascular surgeon: Treats disorders of blood vessels using diagnosis, medical management and surgery.

Congenital heart defects: Structural heart problems from before birth.
Coronary artery disease (CAD): Atherosclerosis of coronary arteries, reducing blood supply to the heart, potentially causing angina, myocardial infarction (heart attack), and death
Atherosclerosis: Hardening and narrowing of arteries due to cholesterol plaque buildup inside artery walls.
Embolism: Blockage of a blood vessel by an embolus (foreign objects like blood clots, air, fat, or tissue).
Blood dyscrasia: A pathological condition of blood's cellular components.
Septicemia: Severe infection associated with bacteria in the blood, potentially leading to sepsis (systemic bacterial infection).
Megaloblastic anemia: Blood disorder with abnormally large, immature red blood cells, often due to deficiencies in folic acid or vitamin B12.