Cardiovascular System - Blood Quiz

Cardiovascular System - Blood

• The cardiovascular system involves the heart and blood vessels.
• Blood carries nutrients, gases, waste, hormones, and other components between cells and body regions.
• Blood is composed of plasma, buffy coat (white blood cells and platelets), and red blood cells.

Blood Components

• Plasma: Mostly water (92%), proteins, nutrients, hormones, antibodies, and other substances.
• Buffy coat: Contains white blood cells and platelets.
• Red blood cells (RBCs/erythrocytes): Filled with hemoglobin, transporting oxygen and some carbon dioxide. Normal count: 5,000,000/mm³. Low count indicates anemia.

Function of Blood

• Transports nutrients, oxygen, hormones, and waste products throughout the body.
• Regulates body temperature and pH.
• Protects against infection and blood loss.

Regulation of RBC Production

• Decreased oxygen delivery stimulates the kidneys to release erythropoietin.
• Erythropoietin stimulates red bone marrow to produce more red blood cells.
• Increased oxygen delivery inhibits the release of erythropoietin.

Fate of Hemoglobin Molecules

• Hemoglobin breaks down into heme and globin.
• Heme breaks down into iron and pigment.
• Iron is reused.
• The pigment forms bilirubin.
• Globin decomposes to amino acids, reused for protein synthesis.

Leucocytes/WBCs

• Function: Protect against harmful bacteria, viruses, parasites, and toxins.
• Five main types: Monocyte, Lymphocyte, Basophil, Eosinophil, Neutrophil.

Platelets/Thrombocytes

• Cell fragments involved in blood clotting.
• Manufactured in red bone marrow.
• Life span is 1-2 weeks.
• Function: Promote blood clotting.

Plasma

• Clear liquid (92% water).
• Contains plasma proteins, antibodies, gases (CO2 and some O2), nutrients, wastes (urea and creatinine), and electrolytes (Na+, K+, Cl−, Ca2+) to maintain osmotic pressure.

The Heart

• Approximately the size of a fist.
• Located: superior surface of diaphragm, left of the midline, anterior to the vertebral column.
• Pumps blood about 70 times per minute.
• Functions from intrauterine life throughout a human's entire life.

Heart Anatomy

• Cone-shaped, approximately the size of a fist.
• Walls consist of cardiac muscle cells.
• Enclosed by the pericardium (a double-walled sac).

Heart Location

• Located in the middle of the chest, between the lungs.
• Apex of the heart is tilted slightly to the left.
• Relations: anteriorly (sternum, costal cartilages, left lung), posteriorly (oesophagus, aorta, thoracic duct), superiorly (base of heart, diaphragm), laterally (lungs, pleura).

Heart Structure

• Structure: Cone-shaped, approximately the size of a fist, four chambers (two atria, two ventricles), walls consist of cardiac muscle cells; enclosed by pericardium.

Pericardium

• Sac surrounding the heart and roots of great vessels.
• Consists of two components: fibrous and serous pericardium, the latter being thin, consisting of visceral and parietal layers.

Pericardial Layers of the Heart

• Visceral layer (epicardium) lines the surface of the heart.
• Parietal layer lines the internal surface of the fibrous pericardium.
• They are separated by fluid-filled pericardial cavity.

Function of the Pericardium

• Protects and anchors the heart.
• Prevents overfilling of the heart with blood.
• Allows for lubricated, friction-free movement.

Heart Wall

• Epicardium: Visceral layer of the serous pericardium.
• Myocardium: Cardiac muscle layer, forming the bulk of the heart.
• Fibrous skeleton of the heart: Interlacing layer of connective tissue.
• Endocardium: Endothelial layer of the inner myocardial surface.

External Heart: Major Vessels (Anterior View)

• Vessels returning blood: superior and inferior vena cava, pulmonary veins.
• Vessels conveying blood away: pulmonary trunk (branches into right and left pulmonary arteries), ascending aorta (branches into brachiocephalic, left common carotid, subclavian arteries).

Heart Chambers

• Two atria (receiving chambers) and two ventricles (discharging chambers).
• Atria have auricle; pectinate muscles mark the atrial walls.
• Blood enters right atrium via superior and inferior vena cavae and coronary sinus.

Valves of the Heart

• Atrioventricular valves: tricuspid and mitral (bicuspid); prevent backflow into atria when ventricles contract.
• Semilunar valves: pulmonary and aortic; prevent backflow into ventricles.

Ventricles of the Heart

• Ventricles are discharging chambers of the heart.
• Filled with trabeculae carneae and papillary muscles.
• Right ventricle pumps blood into the pulmonary trunk.
• Left ventricle pumps blood into the aorta.

Myocardial Thickness and Function

• Atrial walls are thin.
• Ventricular walls are thicker (right is less thick than left).
• Left ventricle has thickest walls to supply blood to the entire body.

Flow of Blood Through the Heart

• Blood flows through pulmonary and systemic circulations.

Blood Supply to the Heart

• Heart is supplied by coronary arteries.
• Two main coronary arteries (left and right) and their branches arise from the aorta.
• These arteries encircle the heart like a crown.

Venous Drainage of the Heart

• Venous drainage occurs via coronary veins.
• Coronary veins form the coronary sinus.
• Coronary sinus is a collection of veins located in the posterior aspect of the heart and empties into the right atrium.

Nerve Supply to the Heart

• Autonomic nervous system (parasympathetic and sympathetic).
• Sympathetic nerves are cardio-acceleratory (increase heart rate and dilate coronary arteries).
• Parasympathetic nerves are cardio-inhibitory (slow down heart rate).

Microscopic Anatomy of Heart Muscle

• Small cells with one central nucleus.
• Branching interconnections between cells.
• Intercalated discs anchor cells, allow ion passage.

Conduction System

• Specialized heart cells generate and coordinate electrical impulses to myocardial cells.
• Consists of: sinoatrial (SA) node, atrioventricular (AV) node, atrioventricular bundle (bundle of His), bundle branches, Purkinje fibers.

Pathological Conditions in the Cardiovascular System

• Congestive heart failure: decreased contractility of myocardium, diminished coronary blood flow, and damaged heart valves.
• Ischemic heart disease: angina pectoris, acute myocardial infarction.
• Congenital abnormalities: atrial septal defect, atrioventricular septal defect, coarctation of the aorta, double-outlet right ventricle, Ebstein's anomaly, hypoplastic left heart syndrome, interrupted aortic arch.

Congenital heart abnormalities

These are defects present from birth. They affect the heart's structure and function. Some examples include different types of septal defects, problems with the aorta, and problems with the valves.

Test your knowledge on the cardiovascular system and the functions of blood. This quiz covers key components like plasma, red blood cells, and the role of blood in nutrient transport and immune defense. Explore how blood regulates vital processes in the body.