Circulatory System

Human Circulatory System Chapter 24.2

Circulatory System Circulatory system is responsible for moving nutrients, gases like oxygen and carbon dioxide, hormones (signal molecules) and fluids like water throughout the body of a multicellular organism.

Circulatory System Overview Circulatory systems includes: Heart – a muscular pump Blood vessels – tubes that transport the blood Blood – fluid that transports substances around the body Also called the cardiovascular system.

Circulatory System Closed system – meaning that blood is always confined to vessels Some simpler animals have open circulation – blood surrounds the organs and tissues, oozing around open cavities inside the organism. This is less efficient.

Blood Vessels Blood vessels – tubes that transport blood 60,000 miles of blood vessels in human body!!! 3 types – What are they? What does each do? Arteries – carry blood away from the heart Capillaries – where material exchange occurs Veins – carry blood to the heart arteries capillaries veins

Arteries Carry blood away from the heart Have relatively thick, muscular walls because blood in arteries is under pressure Elastic - expand as blood is pumped into them, return to normal as pressure decreases. If arteries become hardened because of cholesterol deposits or old age, blood pressure increases, which increases work load of the heart.

Blood Vessels Capillaries Site of materials exchange between blood and cells Tiny – only one cell thick Thin barrier maximizes exchange of gases, nutrients and wastes Blood flow slows down to allow time for movement of oxygen, carbon dioxide, water, glucose and other materials into and out of the blood.

Blood Vessels Red blood cells must go through single file So numerous that every cell in the body is near a capillary! So delicate that it will rupture under a tension 1/3,000 that required to tear toilet tissue!

Veins Carry blood toward the heart Have thinner, less muscular walls because blood in veins is under much lower pressure Have valves that prevent blood from flowing backward Movement of body helps push blood through veins Sometimes sitting or standing still for long periods can cause blood to pool in leg veins, so not enough blood available to brain, and the person faints.

Major veins are the vena cava (upper and lower)

Blood Vessels Remember: Arteries carry blood away from the heart Veins take it toward the heart It has nothing to do with whether the blood is oxygenated or not!

Heart The heart Verses Can you believe…? Heart beats an average of 70 times per minute, 100,000 times per day, or 2.5 billion times in an average lifespan Heart pumps 2,000 gallons of blood per day or 60 million gallons in an average lifespan

Heart Heart is a 4-chambered muscular pump that provides energy to move blood throughout the body. Designed to prevent mixing of oxygenated and deoxygenated blood Right side handles deoxygenated blood Left side pumps oxygenated blood Designed to ensure one-way flow of blood

Heart Anatomy 4 chambers 2 atria –thin walled chambers that collect blood from veins and empty it into the ventricles 2 ventricles – larger, thick-walled chambers that contract, pumping blood out into arteries Left ventricle is the largest because it is working under highest pressure

Heart 4 valves – prevent blood from flowing backward in the heart AV (atrioventricular) valves between atria and ventricles Semilunar valves between ventricles and arteries

Heart Blood vessels Veins Vena cava collect blood from the body Pulmonary vein brings blood from the lungs to the heart (note this vein carries oxygenated blood) Arteries Pulmonary takes blood from heart to lungs Aorta takes blood from left ventricle to the body

Heart Cardiac cycle Blood enters right atrium from vena cava As atrium fills , AV valve opens and right ventricle begins to fill Atrium contracts, filling the ventricle Ventricle contracts , AV valve closes, semilunar valve opens, blood moves into pulmonary artery , then to the lungs

Heart Blood enters capillaries in lungs , where it picks up oxygen, releases carbon dioxide Oxygenated blood flows into pulmonary vein, then enters left atrium AV valve opens and left ventricle begins to fill Atrium contracts, filling the ventricle Ventricle contracts , AV valve closes, semilunar valve opens, blood moves into aorta and is distributed to the body.

Cardiac Cycle Heart muscle itself gets its blood supply from the coronary arteries (which branch off the aorta), not the blood flowing through it.

Cardiac Cycle Animation http://www.guidant.com/condition/heart/interact_5.html

Blood Blood is the fluid that transports substances around the body. Its job is to “nourish and cleanse each living cell.” ( In His Image , Brand and Yancey, p.59) Consists of cells suspended in plasma (liquid)

Blood Cells Red blood cells (erythrocytes) Round cells that carry oxygen Contain hemoglobin , an iron-containing protein that binds oxygen very strongly in lungs, then releases it in oxygen-poor environment of the capillaries

Blood Don’t have a nucleus Live about 120 days Made in the bone marrow We make about 2 million new RBC per second Normally have about 5 million RBC in speck of blood the size of a letter “o”

Blood White blood cells (leukocytes) Several different types, all part of immune system Defend the body against disease (bacteria, viruses fungi worms), toxins and cancer Many act by surrounding and engulfing invaders

Blood When infection present in the body, WBC count increases to combat it. Doctors measure WBC levels to determine presence and extent of infections. More Than Meets the Eye

Blood Platelets – small fragments of WBC that help form blood clots when a blood vessel is damaged. Platelets stick to wound site, attract more platelets

Blood Clotting proteins circulating in blood become activated Fibrin becomes activated by clotting factors, forms a network of threads (like a spiderweb) that traps more platelets and RBC to form a clot

Blood Plasma – watery fluid containing cells and dissolved molecules like proteins, oxygen, carbon dioxide, nutrients (glucose, amino acids and fats), waste products (like urea) and hormones

Circulatory System Introduction (slide 2 for me) Talked about how cells move substances across cell membranes How? Respiratory system brings oxygen into the body, gets rid of carbon dioxide Excretory system removes wastes from cells

Circulatory System Goals for this unit: (Slide 4 for me) Know what the circulatory system is. Know the components of the system What the circulatory system does. How each of the components contributes to the overall function of the whole. What are some of illnesses that result from problems in the circulatory system? (You will get this from the written assignment you’re doing.)

Patients requiring blood almost never receive transfusions of whole blood. Instead, a patient typically receives only the components necessary to treat their clinical condition. Therefore, whole blood donations must be processed to separate out each component. Each component plays a different role in the health and survival of a patient. Red blood cells comprise 40-50% of blood volume. They carry oxygen to vital organs and are required by surgical patients who lose blood during surgery or by trauma victims who have lost blood as a result of an accident or injury. Red blood cells that have been donated can be stored in a refrigerator for up to 42 days. If they are not used within six weeks, they must be thrown away. They can also be stored frozen for up to 10 years. Red cells are the most commonly transfused blood component and most whole blood collections are done with the specific intent of capturing the red cell component. Red Blood Cells carry oxygen to organs. Platelets account for a small percentage of whole blood volume. They are used therapeutically to control bleeding and are often transfused in multiple doses to cancer patients undergoing chemotherapy. Platelets must be stored at room temperature to retain their visibility. Therefore, they have only a five day shelf life before they must be discarded due to possible growth of bacteria. Platelets aid in clotting. Plasma: The remainder of blood volume is plasma, a watery substance in which proteins that trigger blood clotting mechanisms are suspended. Plasma can be transfused directly to a patient, but, more often, plasma is used as a raw material for pharmaceuticals. Plasma is “fractionated” into its different protein components, which are then manufactured into pharmaceuticals. Factor VIII, which is required by hemophiliacs to control bleeding, is one such plasma derived medicine. Plasma can be stored frozen for up to one year. Plasma: the fluid portion of blood.

Blood Illnesses Anemia – too few RBC, can’t carry enough oxygen. Person gets very tired, prone to infections. Treat with iron for less severe cases or blood transfusion for severe cases. Females especially prone to this. Sickle cell anemia

Hemophilia – inadequate clotting Mutations in clotting proteins cause profuse bleeding from even minor wounds. Treat by giving clotting factor. Used to be obtained from blood donors, so many patients contracted HIV and hepatitis. Now use factors produced by bacteria. (Insert human gene into bacteria and have them mass produce the correct protein.)

Blood Clotting disorders Clots can form in blood vessels due to internal damage (fatty plaques, for example). If clot obstructs vessels to heart heart attack. Obstruct vessels to brain stroke. Both are debilitating and can be fatal.

Circulatory System

More Related Content

What's hot (20)

Viewers also liked (20)

Similar to Circulatory System (20)

More from wcadigpub2009zs (6)

Recently uploaded (20)

Circulatory System

Editor's Notes