Chapter 9: The Circulatory System Part 1 Anatomy of Blood and the Heart

Learning Objectives What’s in your blood? Functions of Blood Cells Anatomy of the Heart

Purpose of the Circulatory System The heart pumps blood throughout your body Blood picks up and drops off different substances to ensure that cells have oxygen and carbon dioxide as well as other waste products are properly disposed of

Your Blood Considered a connective tissue When your blood is centrifuged (spun really fast) it separates materials by density Your blood consists of a liquid component called plasma You blood also consists of 3 formed components Red Blood Cells White Blood Cells Platelets

Plasma 92% is water 8% is made of plasma proteins, salt, nutrients, urea, hormones and vitamins 3 Types of Plasma Proteins Albumin – maintains proper osmotic pressure Fibrinogen – helps with clotting Immunoglobulin – AKA antibodies

Red Blood Cells AKA Erythrocytes RBCs contain a protein called hemoglobin which carries oxygen Oxyhemoglobin is bright red (makes your arteries look red) Deoxyhemoglobin is purplish-blue (makes your veins look blue Live for about 4 months

White Blood Cells AKA leukocytes Not as many WBCs as RBCs Fight off invading microbes, bacteria, viruses Two main types of WBCs Granular Leukocytes Agranular Leukocytes

White Blood Cell Functions Agranular Leukocytes - Lymphocytes White Blood Cells White Blood Cell Functions Type of White Blood Cell Specific Functions Granular Leukocytes Eosinophils Numbers increase during allergic reactions and parasitic infections Neutrophils First to respond to infections - phagocytize Basophils Seep out of vessels at site of injury and release histamine to dilate vessels Agranular Leukocytes - Lymphocytes B lymphocytes Form antibodies to fight infection T lymphocytes Destroy cells that contain foreign material Monocytes Mature into macrophages, engulf disease-causing microbes, stimulate other WBCs into action

Platelets AKA thrombocyte Tiny fragments of cells Large cells in the bone marrow called megakaryocytes break into fragments which are platelets Help the clotting process by plugging up the injured blood vessels

The Heart Main organ of the circulatory system The heart is the driving force behind the movement of the blood The pressure is generates by the pumping action, forces the blood through the vessels The heart lies between the lungs and behind and slightly to the left of the sternum

Layers of the Heart Pericardium/Pericardial Tissue: thick layer of muscle tissue and a protective membrane that folds into two layers surrounding the heart Endothelial Tissue: endothelial tissue that lines the inside of the heart and is continuous with all your blood vessels

Layers of the Heart Pericardial Cavity: Coronary vessels – blood vessels that supply the tissues of the heart with nutrients and oxygen Myocardium: muscular layer of the heart

Layers of the Heart Epicardium: inner layer of the pericardium, covers the myocardium and secretes perocardial fluid to help lubricate so tissues don’t rub together during contraction Parietal Pericardium: outermost layer of the heart, thin, white, fibrous connective tissue that joins the major blood vessels

4 Chambers of the Heart Right Atrium Left Atrium Right Ventricle Left Ventricle Interatrial Septum – wall dividing the two atria Interventricular Septum – wall dividing the two ventricles

Heart Valves The heart contains several valves Valves keep blood flowing in the right direction on the pathway and allows the right amount of blood into each chamber The names of the valves can tell you their location or certain characteristics Semilunar Valves - half moons Atrioventricular Valves (AV) – between the atria and ventricles Bicuspid Valve – 2 flaps Tricuspid Valve – 3 flaps

Review Questions What are the 3 formed components of blood? List some of the types of white blood cells What is the name of the thin fibrous tissue that covers the heart? What are the four chambers of the heart? Under what conditions does blood look purplish blue? What types of substances are carried in plasma? What is the purpose of the circulatory system?