Parts of the Circulatory System

Transcription

1 Circulatory System

2 Objectives Identify the function of the circulatory system Describe the structure and function of the human heart Describe the three types of blood vessels Describe the function of the lymphatic system

3 Parts of the Circulatory System The circulatory system is made up of: The cardiovascular system The lymphatic system The cardiovascular system is made up of: Blood Heart Blood vessels The lymphatic system is made up of: Lymph Lymph nodes Lymph vessels

4 Functions of the Circulatory System Brings oxygen, nutrients, and hormones to cells Fights infection Removes cell wastes Helps to regulate body temperature

5 The heart is a hollow organ composed almost entirely of muscle It is about the size of your fist Pericardium is a tough, saclike membrane that surrounds the heart and secretes a fluid that reduces friction as the heart beats Myocardium is a thick muscle layer that surrounds the heart The Heart

6 The Heart The septum vertically divides the heart into two sides The right side pumps oxygen-poor blood to the lungs The left side pumps oxygen-rich blood to other parts of the body

7 The Heart Each side is divided into an upper and lower chamber Atrium upper chamber (plural is atria ) Ventricle lower chamber The heart has 4 chambers two atria two ventricles chambers

8 Circulation Through The Heart Blood high in CO 2 and low in O 2 enters the heart through the vena cava and into the right atrium Right atrium pumps the blood to the right ventricle Right ventricle pumps blood to the lungs Blood has CO 2 removed and receives O 2 in the lungs

9 Circulation Through The Heart Blood high in O2 re-enters the heart through the left atria Left atria pumps blood to the left ventricle Left ventricle pumps blood to the rest of the body Aorta largest artery in the human body that pumps blood from the left ventricle to the rest of the body

10 Circulation Through The Heart Valves connective tissue between the atria and ventricles that prevents the backflow of blood Blood moving from the atria holds the valves open When the ventricles contract, the valves close This prevents blood from flowing back into the atria

11 Not this one Heartbeat

12 Heartbeat Two networks of muscle fibers in the heart One in the atria One in the ventricles When a single fiber is stimulated, all the fibers are stimulated, and the network contracts as a whole

13 Heartbeat Each contraction begins in the sinoatrial (SA) node Sinoatrial node the nerve tissue in the right atrium that regulates the contraction rate of the heart Also called the pacemaker The impulse sent by the SA node reaches the atrioventricular (AV) node The AV node, located in the septum, sends the impulse to the ventricles, which causes them to contract

14 Heartbeat Heartbeat has two phases: Systole occurs when ventricles contract Pumps blood out of the heart Diastole occurs when ventricles relax and blood flows into the atria

15 Blood Vessels When blood leaves the left ventricle, it passes through the aorta The aorta is the first of a series of blood vessels that carry blood throughout the circulatory system There are 3 types of blood vessels: Arteries Capillaries Veins

16 Arteries are large vessels that carry blood from the heart to the tissues of the body All arteries carry oxygenrich blood Except for pulmonary arteries Arteries have thick walls to withstand pressure Arteries branch off into smaller arteries called arterioles Arteries

17 Capillaries Arterioles branch off into capillaries Capillaries are the smallest blood vessels in the body Walls are only one cell thick They carry O 2 and nutrients to cells and absorb CO 2 and other wastes

18 Veins Veins blood vessels that carry blood back to the heart Large veins have valves in them to keep blood moving towards the heart Venules are smaller veins that collect blood from the capillaries

19 Pulmonary Circulation Pulmonary circulation pathway of circulation between the heart and the lungs The right side of the heart pumps blood to the lungs CO 2 is removed from the blood and O 2 is absorbed Oxygen-rich blood returns to the heart

20 Systemic Circulation Systemic circulation the movement of blood between the heart and all parts of the body except the lungs The left side of the heart pumps oxygen-rich blood to the rest of the body Coronary circulation supplies blood to the heart itself Renal circulation supplies blood to the kidneys Hepatic portal circulation moves nutrient-rich blood from the small intestine to the liver

21 The Lymphatic System The lymphatic system is a network of vessels, nodes, and organs that collects the fluid that is lost by the blood and returns it back to the circulatory system The fluid lost by the blood is called lymph Lymph collects in lymphatic capillaries and slowly flows into larger and larger lymph vessels Ducts collect the lymph and return it to the circulatory system

22 The Lymphatic System Lymph nodes are bean-shaped enlargements in lymph vessels Lymph nodes act as filters that trap bacteria and other microorganisms that cause disease Lymphocytes are white blood cells stored in lymph nodes that are specialized to fight disease

23 Review Questions Identify the functions of the circulatory system The circulatory system brings oxygen, nutrients, and hormones to cells, fights infection, removes cell wastes, and helps to regulate body temperature Describe the structure and function of the human heart The upper chamber that receives the blood is called the atrium The lower area that pumps blood out is called the ventricle The heart pumps blood

24 Review Questions Name the three types of blood vessels. Arteries Veins Capillaries Describe the role of the lymphatic system. The lymphatic system collects the fluid that is lost by the blood and returns it back to the circulatory system