The Circulatory System Sections 11.1, 11.2, 11.3

The Circulatory System Learning Goal: To explore the circulatory system. Success Criteria: I know I am succeeding when I can… discuss the functions of the circulatory system list the main parts of the circulatory system describe the components of blood and the function of each discuss the different types of blood vessels, including their structures and functions explain the value of pulse and blood pressure measurements

The Circulatory System Circulatory System: the organ system that transports oxygen, nutrients and other materials throughout the body and carries away waste also maintains body temperature and transports white blood cells to fight disease

The Circulatory System Cont’d… the circulatory system is made up of the heart, blood, and blood vessels

Blood blood is connective tissue there are four components of blood

1. Plasma liquid in which blood cells and platelets are suspended 90% of plasma is water plasma contains a variety of substances: oxygen, proteins, and nutrient molecules such as glucose, minerals, and vitamins, along with carbon dioxide plays an important role in balancing the amount of water within the body and maintains volume of blood

2. Red Blood Cells (Erythrocytes) carry oxygen from the lungs to the body cells, and to carry carbon dioxide from the body cells back to the lungs to be expelled oxygen binds to hemoglobin molecules on the RBC Red blood cells lose their nucleus’ to make more room for hemoglobin to increase their capacity to transport oxygen a.k.a erythrocytes biconcave disks (increases surface area) carry oxygen from the lungs to the body cells, and to carry carbon dioxide from the body cells back to the lungs to be expelled oxygen binds to hemoglobin molecules on the RBC Oxygen lose their nucleus’ to make more room for hemoglobin to increase their capacity to transport oxygen made in the bone marrow and once they die (approx. 120 days) they are removed by the liver and spleen if the RBC are too low, the kidney will release the EPO hormone which will stimulate the marrow to make more

2. Red Blood Cells (Erythrocytes) RBC are made in the bone marrow and once they die (approx. 120 days) they are removed by the liver and spleen if the RBC are too low, the kidney will release the EPO hormone which will stimulate the bone marrow to make more a.k.a erythrocytes biconcave disks (increases surface area) carry oxygen from the lungs to the body cells, and to carry carbon dioxide from the body cells back to the lungs to be expelled oxygen binds to hemoglobin molecules on the RBC Oxygen lose their nucleus’ to make more room for hemoglobin to increase their capacity to transport oxygen made in the bone marrow and once they die (approx. 120 days) they are removed by the liver and spleen if the RBC are too low, the kidney will release the EPO hormone which will stimulate the marrow to make more

3. White Blood Cells (Leukocytes) fight against harmful bacteria, viruses, and other organisms that can cause diseases several different types of leukocytes (all have nuclei) formed in bone marrow

3. White Blood Cells (Leukocytes) Cont’d… many leukocytes use phagocytosis (engulfing) to destroy bacteria or harmful substances within cells once the cell has engulfed its target, enzymes are released and destroy the target and the leukocyte itself the remnants of the leukocyte and whatever it engulfed are left behind as a whitish substance known as pus formed in bone marrow

4. Platelets platelets are small cell fragments that are essential in blood clotting, or coagulation Produced by stem cells in bone marrow

4. Platelets Cont’d… when a blood vessel is broken, platelets stick to the blood vessel wall to seal the hole in the blood vessel a blood clot (made of fibrin from the plasma, platelets, and blood cells) is then formed underneath that stops the leakage of blood and allows time for the injury to heal Produced by stem cells in bone marrow

Blood Vessels blood vessels form a network of tubes that transport blood throughout the body there are three main types of blood vessels Produced by stem cells in bone marrow

i. Arteries and Arterioles carries blood away from the heart toward the body tissues have thick , elastic walls to withstand pressure of the blood being pump from the heart

i. Arteries and Arterioles Cont’d… when blood is forced through the artery by the contraction of the heart, the artery expands felt as the pulse of the artery is fairly large, close to the skin, and in front of a bone or other firm structure there are different pulse points on the body

i. Arteries and Arterioles Cont’d… arteriole: the smallest artery since they have smooth muscle in their walls, signals from the nerves can regulate the diameter of the arterioles and control the blood flow to certain parts of the body vasodilation increases the blood flow to tissues vasoconstriction decreases the blood flow to tissues

ii. Capillaries networks of blood vessels that supply oxygen and nutrients to EVERY cell throughout the body tissues (no body cell is farther than two cells away from a capillary) have VERY thin walls (one cell thick) to allow for diffusion of O2, CO2, nutrients and wastes

ii. Capillaries Cont’d… there are pre-capillary sphincter muscles where the arteriole branches into a capillary if blood is not needed in a particular capillary network, the pre-capillary sphincters contract and reduce blood flow during exercise, for example, the arterioles and sphincters are fully relaxed, and the blood flow to the muscles is increased

iii. Veins and Venules veins and venules (smallest veins) carry deoxygenated blood containing carbon dioxide and other waste products from the body tissues to the heart veins are thinner and less elastic than arteries, since blood flowing through veins is low pressure after moving through the capillaries

iii. Veins and Venules Cont’d… some veins have internal valves to make sure blood moves in the right direction also when our muscles contract, they squeeze the veins which increases the pressure in the veins and helps push the blood back toward the heart

The Circulatory System Learning Goal: To explore the circulatory system. Success Criteria: I know I am succeeding when I can… discuss the functions of the circulatory system list the main parts of the circulatory system describe the components of blood and the function of each discuss the different types of blood vessels, including their structures and functions explain the value of pulse and blood pressure measurements

Homework 11.1 questions #1-5 11.2 questions #1-2 11.3 Questions #1-6