Introduction to the Cardiovascular System

Introduction to the Cardiovascular System

• The cardiovascular system is responsible for transporting substances throughout the body.
• It comprises blood, heart, and blood vessels.
• The cardiovascular system delivers nutrients and removes waste products from tissues throughout the body.
• The conveying medium is liquid.

Function of the Cardiovascular System

• Transports nutrients and hormones.
• Removes waste products.
• Enables gaseous exchange.
• Supports the immune system.
• Blood vessels carry blood, oxygen, carbon dioxide, nutrients, and waste.
• The heart pumps blood throughout the blood vessels.

Components of the Cardiovascular System

• Blood
• Heart
• Blood vessels (arteries, capillaries, and veins)

Blood

• Blood consists of blood cells and plasma.
• Blood cells include erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets).
• Plasma is the fluid portion of blood.

Heart

• The heart is a four-chambered, hollow, muscular organ, roughly the size of a fist.
• Located superior to the diaphragm, left of midline, and anterior to the vertebral column.

Blood Vessels

• Arteries: thick-walled tubes with elastic fibers and smooth muscles, carry oxygenated blood away from the heart.
• Capillaries: microscopic vessels, one cell thick, enabling nutrient and gas exchange.
• Veins: thinner walled than arteries, carry deoxygenated blood back to the heart.

Classification of Arteries

• Elastic arteries (e.g., aorta, common carotid arteries, subclavian arteries).
• Muscular arteries (e.g., renal, testicular, radial, and tibial arteries).
• Arterioles (smaller than 0.1 mm)

Capillaries

• The smallest blood vessels connecting arteries and veins, crucial for nutrient and gas exchange.
• Types: continuous (skin, lungs, muscle, and connective tissue) , fenestrated (pancreas, endocrine glands, small intestine, and choroid plexus), sinusoids (liver, spleen, bone marrow)

Veins

• Carry deoxygenated blood back to the heart.
• One-way valves prevent backflow.

Anastomosis

• Communication between vessels.
• Arterial: Actual (end-to-end or convergent) (e.g., palmar, plantar arches, circle of Willis, labial, intestinal arcade); potential (e.g., arteriovenous anastomosis)
• Arteriovenous: Blood flow between arteries and veins.

End Arteries

• Do not have anastomoses. If blocked, the tissue beyond is deprived of blood supply. (e.g., arteries of retina, spleen, kidney, metaphyses of long bones)

Circulation

• Coronary circulation: flow of blood within the heart
• Pulmonary circulation: flow of blood between the heart and lungs
• Systemic circulation: flow of blood between the heart and body cells

Portal Circulation

• Flow of blood between two capillary beds before draining into a systemic vein

Fetal Circulation

• Unique circulatory adaptations to support fetal development.

Applied

• Cardiovascular diseases and disorders (e.g., hypertension, stroke, atherosclerosis, aneurysms, coronary artery disease, heart attack, congestive heart failure, anemia)
• Problems affecting both children and adults.

Questions

• Question 1: The correct answer for which of following are examples of elastic arteries is Aorta
• Question 2: Correct answer for examples of end arteries: Central artery of retina, Central branches of cerebral arteries, Splenic artery
• Question 3: Correct answer for what are the location of arteriovenous anastomosis : Skin of lips, Erectile tissue of penis, Thyroid gland
• Question 4: Correct answer for which are examples of portal blood: Hepatic circulation, Circulation of hypophysis cerebri
• Question 5: Which are not features of veins? Thin walls, Thin tunica media, Thin tunica adventitia