Cardiovascular Anatomy and Physiology

Cardiovascular Anatomy and Physiology

• The heart is a hollow, conical, muscular organ located in the center of the chest, surrounded by a membrane called the pericardium.
• The heart has three layers: epicardium, myocardium, and endocardium, and four chambers: right and left atria, and right and left ventricles.
• Four valves (tricuspid, bicuspid, pulmonary semilunar, and aortic semilunar) keep blood flowing in the right direction.

Heart Function

• The heart pumps blood through a cardiac cycle, which includes atrial contraction, ventricular contraction, and a recovery period.
• The cardiac cycle pumps deoxygenated blood from the body to the lungs, where it is reoxygenated, and oxygenated blood from the lungs to the body.

Heart Regulation

• The medulla of the brain is the command center of the cardiovascular system, sending messages to the electrical pacemaker of the heart, the sinoatrial (SA) node.
• The SA node triggers impulses at a rate of 60-100 per minute, which are transmitted through the atrioventricular (AV) node and the Bundle of His to the Purkinje fibers, triggering ventricular contraction.

Vascular Anatomy

• Vascular structures include arteries, arterioles, capillaries, venules, and veins, which distribute blood to and from the body organs and tissues.
• Arteries carry oxygenated blood from the heart to the body, except for the pulmonary arteries, which carry deoxygenated blood to the lungs.
• Veins carry deoxygenated blood from the body back to the heart, except for the pulmonary veins, which carry reoxygenated blood from the lungs.

Blood Components

• Blood is a living tissue containing various cells and substances, including red blood cells (erythrocytes), white blood cells (leukocytes), and platelets.
• Plasma makes up 55-60% of blood volume, and contains water, proteins, glucose, electrolytes, hormones, and other substances.
• Red blood cells contain hemoglobin, carrying oxygen throughout the body and giving blood its red color.

Blood Group Systems

• Each person has one of four blood types in the ABO system: A, B, AB, or O, and one of two designations in the Rhesus (Rh) system: Rh-positive or Rh-negative.
• Type O blood is the universal donor type, and type AB blood is the universal recipient type.

Hemostasis and Coagulation

• Hemostasis is the steady state of blood, maintaining blood throughout the body despite injuries.
• The coagulation process involves five phases: vascular phase, platelet phase, coagulation phase, clot retraction, and fibrinolysis.
• Direct pressure assists in the coagulation process by slowing blood flow and constricting the vessel, facilitating clot formation.

Blood Circulation

• Blood circulates through the heart, arteries, veins, and capillaries, carrying nourishment, vitamins, electrolytes, hormones, antibodies, warmth, and oxygen to the body's tissues.
• Blood also transports wastes and carbon dioxide to organs that can excrete them from the body.
• Adults have 4 to 6 liters of whole blood in circulation, depending on sex and body size.

Blood Composition

• Blood is composed of 55-60% plasma and 40-45% blood cells.
• Plasma is 92% water and 8% a mixture of proteins, glucose, electrolytes, fibrinogen, and other substances.
• Blood cells include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets.

Red Blood Cells

• Red blood cells contain hemoglobin, a complex iron-containing protein that carries oxygen throughout the body and gives blood its red color.
• Red blood cells are flexible, allowing them to pass easily through the circulatory system.
• Red blood cells circulate in the bloodstream for about 120 days before being replaced by new cells produced in the bone marrow.

White Blood Cells

• White blood cells come in many varieties, including monocytes, lymphocytes, and granulocytes (neutrophils, eosinophils, and basophils).
• White blood cells defend the body against infection by destroying pathogens and producing antibodies.

Platelets

• Platelets are cells necessary for clotting and function by sticking to the lining of blood vessels.

Blood Group Systems

• Each person has one of four blood types in the ABO system: A, B, AB, or O.
• Each person also has one of two designations in the Rhesus (Rh) system: Rh-positive or Rh-negative.
• The presence or absence of A and B antigens determines blood type.

Vascular Anatomy

• The cardiovascular system includes a network of arteries, veins, and capillaries.
• Arteries carry freshly oxygenated blood to the body, while veins carry deoxygenated blood back to the heart.
• Capillaries are permeable and function as exchange vessels, where oxygen and nutrients move into body cells and carbon dioxide and other wastes move out.

Hemostasis and Coagulation

• Hemostasis is the steady state of blood that maintains blood in its liquid form while preventing excessive bleeding.
• Coagulation is the process of forming a blood clot to plug injuries to small blood vessels.
• The five stages of coagulation include the vascular phase, platelet phase, coagulation phase, clot retraction, and fibrinolysis.

Cardiovascular Anatomy and Physiology

• The heart is a hollow, conical, muscular organ that pumps blood throughout the body.
• The heart has four chambers: the right and left atria, and the right and left ventricles.
• The heart has four valves that keep blood flowing in the right direction.
• The cardiac cycle includes atrial contraction, ventricular contraction, and a recovery period, and occurs 60-100 times per minute.
• The medulla of the brain is the command center of the cardiovascular system, and the cardiac cycle requires a conduction system to send electrical impulses to the heart.

Blood Composition and Function

• Blood circulates through the heart, arteries, veins, and capillaries, carrying nourishment, vitamins, electrolytes, hormones, antibodies, warmth, and oxygen to the body's tissues.
• Blood also transports wastes and carbon dioxide to organs that can excrete them from the body.
• Adults have 4 to 6 liters of whole blood in circulation, depending on sex and body size.
• Blood is composed of 55% to 60% plasma, which is about 92% water and 8% a mixture of proteins, glucose, electrolytes, fibrinogen, and other substances.
• The remaining 40% to 45% is blood cells: red blood cells, white blood cells, and platelets.

Blood Cells

• Red blood cells contain hemoglobin, a complex iron-containing protein that carries oxygen throughout the body and gives blood its red color.
• Red blood cells are flexible, allowing them to pass easily through the circulatory system.
• Red blood cells circulate in the bloodstream for about 120 days, after which they disintegrate and bone marrow replaces them with new red blood cells.
• White blood cells come in many varieties: monocytes, lymphocytes, and granulocytes (including neutrophils, eosinophils, and basophils).
• Each type of white blood cell has a specific function, but in general, they defend the body against infection.
• Platelets are cells necessary for clotting, functioning by sticking to the lining of blood vessels.

Blood Group Systems

• Each person has one of four blood types in the ABO system: A, B, AB, or O.
• The presence or absence of the A and B antigens determines the type.
• Type A blood has the A antigen, type B has the B antigen, type AB has both, and type O has neither.
• Furthermore, type A plasma contains anti-B antibodies, type B plasma contains anti-A antibodies, type AB plasma contains no antibodies, and type O contains both antibodies.

Vascular Anatomy

• Vascular structures include arteries (which branch into arterioles and capillaries) and veins (which branch into venules and capillaries).
• Arteries carry freshly oxygenated blood to the body, with the exception of pulmonary arteries, which carry deoxygenated blood to the lungs.
• Veins carry deoxygenated blood from the body back to the heart, with the exception of pulmonary veins, which carry reoxygenated blood back to the heart from the lungs.
• Capillaries are permeable and function as exchange vessels, allowing oxygen and nutrients to move into body cells and carbon dioxide and other body wastes to move out.

Hemostasis and Coagulation

• Hemostasis is the steady state of blood, maintaining blood flow throughout the body regardless of circumstances.
• Hemostasis includes components of the clotting process necessary for managing bleeding while blood is still circulating in its usual liquid form.
• Coagulation has five distinct phases: vascular phase, platelet phase, coagulation phase, clot retraction, and fibrinolysis.
• The coagulation process involves substances such as fibrinogen, calcium, and clotting factors working together to form a blood clot.