Chapter 33 Circulatory and Respiratory Systems 33.1: The Circulatory System 33.2: Blood and the Lymphatic System 33.3: The Respiratory System

The circulatory system moves blood to all parts of the body. veins arteries The system includes the heart, arteries, veins, and capillaries. heart pumps blood throughout body arteries move blood away from heart veins move blood back to heart capillaries get blood to and from cells

Circulatory System There are three major functions of the circulatory system The heart is a muscular pump that moves the blood through two pathways transporting blood, gases, nutrients collecting waste materials maintaining body temperature

The tissues and structures of the heart make it an efficient pump. Cardiac muscle tissue works continuously without tiring. NORMAL HUMAN HEART

The heart has four chambers: two atria, two ventricles. Valves in each chamber prevent backflow of blood. aortic valve left atrium mitral valve left ventricle septum pulmonary valve right atrium tricuspid right ventricle Muscles squeeze the chambers in a powerful pumping action.

The heartbeat consists of two contractions SA node, or pacemaker, stimulates atria to contract AV node stimulates ventricles to contract SA node VA node

Blood flows through the heart in a specific pathway. oxygen-poor blood enters right atrium, then right ventricle right ventricle pumps blood to lungs oxygen-rich blood from lungs enters left atrium, then left ventricle left ventricle pumps blood to body

The heart pumps blood through two main pathways. Pulmonary circulation occurs between the heart and the lungs. oxygen-poor blood enters lungs excess carbon dioxide and water expelled blood picks up oxygen oxygen-rich blood returns to heart

Systemic circulation occurs between the heart and the rest of the body. oxygen-rich blood goes to organs, extremities oxygen-poor blood returns to heart The two pathways help maintain a stable body temperature.

Arteries, veins, and capillaries transport blood to all parts of the body. The circulatory system transports materials throughout the body Arteries carry blood away from the heart. blood under great pressure thicker, more muscular walls ARTERY VEIN CAPILLARIES arteriole venule endothelium connective tissue smooth muscle valve

Veins carry blood back to the heart. blood under less pressure thinner walls, larger diameter valves prevent backflow ARTERY VEIN CAPILLARIES arteriole venule endothelium connective tissue smooth muscle valve

Capillaries move blood between veins, arteries, and cells. ARTERY VEIN CAPILLARIES arteriole endothelium connective tissue smooth muscle venule valve

Blood pressure is a measure of the force of blood pushing against artery walls. systolic pressure: left ventricle contracts diastolic pressure: left ventricle relaxes High blood pressure can precede a heart attack or stroke.

Lifestyle plays a key role in circulatory diseases. Some choices lead to an increased risk of circulatory diseases. smoking long-term stress excessive weight lack of exercise diet low in fruits and vegetables, high in saturated fats

Circulatory diseases affect mainly the heart and the arteries. artery walls become thick and inflexible plaque blocks blood flow in arteries

Blood Blood is a complex tissue that transports materials Blood is composed mainly of cells, cell fragments, and plasma Whole blood is made up of different materials. plasma red blood cells white blood cells platelets red blood cells, white blood cells, and platelets plasma

Blood—quick summary: Plasma = 90 percent water and helps with blood clotting Red blood cells = transport oxygen using hemoglobin White blood cells = guard against infection Platelets = fragments of cells used for blood clotting

Plasma About 55 percent of total blood volume is plasma Plasma is about 90 percent water, which helps to control body temperature Fibrinogen = special plasma protein that is necessary for blood to clot

Plasma Plasma is a key factor in maintaining homeostasis. molecules diffuse into and out of plasma contains proteins that stabilize blood volume contains clotting factors contains immune proteins

Platelets and different types of blood cells have different functions. The bone marrow manufactures most of the blood components. red blood cell platelet white blood cell

Red Blood Cells Most numerous cells in blood are red blood cells Main function of red blood cells is to transport oxygen. Red blood cells get their color from the iron in hemoglobin, a protein that binds oxygen in the lungs and carries it throughout the body Red blood cells are disks that are thinner in their center than along their edge Red blood cells circulate for an average of 120 days before they are destroyed in the liver and spleen.

Red blood cells make up 40-45 % of all blood cells. transport oxygen to cells and carry away carbon dioxide have no nuclei and contain hemoglobin

White Blood Cells White blood cells guard against infection, fight parasites, and attack bacteria. They are produced from stem cells in bone marrow and can live for years. They are not confined to blood vessels—many white blood cells can slip through capillary walls to attack foreign organisms in different tissues

White blood cells fight pathogens and destroy foreign matter. red blood cell platelet white blood cell

Protein markers define blood types and Rh factors. ABO blood group the most common Rh factor can be negative or positive blood types must be compatible for transfusions

Platelets Blood clotting is made possible by plasma proteins and cell fragments called platelets

Platelets help form clots that control bleeding. fibrin red blood cell white blood cell

Platelets—How the help blood clotting When platelets come in contact with the edges of a broken blood vessel, their surface becomes sticky, and they cluster around the wound Platelets then activate enzymes to start blood clotting Clot seals damaged area & prevents further blood loss

The Lymphatic System As blood passes through capillaries, some blood cells and components of plasma move through capillary walls and into the fluid between cells, carrying nutrients, dissolved oxygen, and salts.

The Lymphatic System Most of this fluid, known as lymph, is quickly reabsorbed into capillaries, but not all of it. The rest goes into the lymphatic system, a network of vessels, nodes, and organs that collects the lymph, “screens” it for microorganisms, and returns it to the circulatory system. The lymphatic system is also involved in the absorption of nutrients and in immunity.

Role in Immunity Hundreds of small bean-shaped enlargements—called lymph nodes—are scattered along lymph vessels throughout the body Lymph nodes act as filters, trapping microorganisms, cancer cells, and debris as lymph flows through them. White blood cells inside lymph nodes engulf and destroy this cellular “trash.”

Role in Immunity When large numbers of microorganisms are trapped in lymph nodes, the nodes become enlarged. The “swollen glands” that are symptoms of certain kinds of infections are actually swollen lymph nodes.

The respiratory and circulatory systems work together to maintain homeostasis. Oxygen-poor blood Oxygen-rich blood The respiratory and circulatory systems bring oxygen and nutrients to the cells. The circulatory system transports blood and other materials. brings supplies to cells carries away wastes separates oxygen-poor and oxygen-rich blood

The respiratory system is where gas exchange occurs. picks up oxygen from inhaled air expels carbon dioxide and water nose sinus mouth epiglottis trachea lungs

The respiratory system moves gases into and out of the blood. The lungs contain the bronchi, bronchioles, and alveoli. Millions of alveoli give the lungs a huge surface area. The alveoli absorb oxygen from the air you inhale. alveoli bronchiole

Breathing involves the diaphragm and muscles of the rib cage. Air flows from areas of high pressure to low pressure. Air inhaled. Muscles contract and rib cage expands. Diaphragm flattens and moves downward. Air exhaled. Muscles and rib cage relax. Diaphragm relaxes and rises.

Gas exchange occurs in the alveoli of the lungs. The respiratory system exchanges oxygen and carbon dioxide. Oxygen and carbon dioxide are carried by the blood to and from the alveoli. oxygen diffuses from alveoli into capillary oxygen binds to hemoglobin in red blood cells carbon dioxide diffuses from capillary into alveoli GAS EXCHANGES ALVEOLI alveolus capillary co2 o2 Co2 diffuses into alveolus. O2 diffuses into blood. capillaries

Breathing is regulated by the brain stem. midbrain pons medulla oblongata spinal chord

Respiratory diseases interfere with gas exchange. Lung diseases reduce airflow and oxygen absorption. Emphysema destroys alveoli. Asthma constricts airways. Cystic fibrosis produces sticky mucus.

Smoking is the leading cause of lung diseases. Bronchitis, emphysema, cancer