The Circulatory System -also called Cardiovascular System Consists of the heart, the blood vessels, and the blood

Evolutionary Trends of the Circulatory System Simple Complex

Functions of the Circulatory System Main Functions: 1.Transports O 2 & nutrients (sugars, amino acids, hormones) to the cells 2.Carries wastes away from cells Also, works with the immune system to protect body against disease causing pathogens

Parts of the Blood Plasma – thick, yellowish liquid,mostly water, in which blood cells are suspended Red blood cells (erythrocytes) –Transport O 2 to body/ remove CO 2 –Red in color due to the hemoglobin (iron containing protein) –Produced in red bone marrow, average life span of 120 days, destroyed by spleen later White blood cells (leukocytes) –Guard against infection –Some work with the immune system to produce antibodies Platelets: cell fragments a.Stick to broken blood vessels b.Helps body heal wounds by forming clots

When you get cut why does the bleeding eventually stop? You have plasma proteins and cell fragments called platelets. When there is a broken blood vessel, platelets start to accumulate at the site and release clotting factors. These factors form a web (like the pic. to the right) of filaments that stops the bleeding.

Blood Vessels Adults have over 60,000 miles of vessels in their bodies The blood volume in our bodies = 8% of our total weigh t

Three Types of Blood Vessels 1.Arteries o Large vessels that carry blood AWAY from the heart to the tissues of the body o Except for the pulmonary arteries, all arteries carry oxygen-rich blood.

2. Veins Large vessels that return blood TO the heart. –Have valves to keep blood from flowing backwards –Carrying oxygen-poor blood

Valves are also in the veins Prevent backflow and push blood against gravity to the heart(systemic circulation). One way flow. Leaky valves in extremities can cause blood to “pool”=varicose veins Treatment= – Sclerotherapy (medicine injected into vein) –Vein stripping

3. Capillaries o Smallest blood vessel; site of gas exchange: brings nutrients and oxygen to the tissues and absorbs carbon dioxide and waste products o The walls of capillaries are only one cell thick, and most are so narrow that blood cells must pass through them in single file.

The Heart: Some Facts Hollow organ about the size of your clenched fist. Contracts on average 72 times per minute. Pumps about 70 mL of blood with each contraction.

The Heart 1. Heart – muscular organ  4 chambers  Pumps blood from heart to lungs & back to heart, to tissues throughout body 2. Pericardium- outer covering of the heart; provides protection for heart.  Myocardium – Heart’s muscular wall that contracts to pump blood out of the heart.

3. Septum: muscular wall in heart  Separates right side from left side  Keeps O 2 poor & O 2 rich blood from mixing 4. Atria – 2 upper chambers  Receive blood from body (right) or lungs (left) & pump blood into ventricles 5. Ventricles – 2 lower chambers  Pump blood out of heart to lungs (right) or aorta (left)

2 chambers: fish 3 chambers: amphibians, most reptiles 4 chambers: birds, mammals. The 4 chambered heart is more efficient because the oxygenated and deoxygenated blood are never mixed. The Heart

6. Natural Pacemaker- “sets the pace” Sinoatrial node (SA node) – – found in the upper part of the right atrium of the heart –a specialized bundle of neurons that act as the heart's natural pacemaker –the SA node "fires" at regular intervals to cause the heart of beat with a rhythm of about 60 to 70 bpm(healthy, resting).

Artificial Pacemaker A medical device placed under your skin near heart which uses electrical impulses, delivered by electrodes contacting the heart muscles, to regulate the beating of the heart if you have arithemiasmedical deviceelectrodes heart

Two Paths of Circulation Systemic-blood circulates from the heart to the body and back to the heart Pulmonary-blood circulates from the heart to the lungs and back to the heart How the Heart Works…..

Circulation Through the Body The heart functions as two separate pumps: 1.Right Side - Pumps oxygen-poor blood to the lungs. o Known as pulmonary circulation 2.Left Side - Pumps oxygen-rich blood to the rest of the body. o Known as systemic circulation

Pathway of Blood Flow Through the Heart 1.Blood enters the heart through the right (3) and left (9) atria. 2.As the heart contracts, blood flows into the ventricles (5, 11). 3.Then out from the ventricles to either the body or the lungs. Valves – Flaps of connective tissue that prevents blood from flowing backwards. –Exist between the atria and ventricles. –Also exist at the end of the ventricles.

Heart beats & Blood Pressure Normal heart sound –Lub-Dub – “lub” is the bicuspid and tricuspid valve closing and the “dub” is the semilunar valves closing Blood pressure is the force of the blood on the walls of the arteries. (Systolic over Diastolic) –Diastole – period of time when the heart-atria- fills with blood (relaxation) –Systole – the contraction of the ventricles  Normal blood pressure is 110/70

Circulatory System Diseases 1. Leukemia: bone marrow produces abnormal WBCs. At first, leukemia cells function normally. In time, there are too many & they crowd out normal WBCs, RBCs & platelets. 2. Hemophilia: an inherited disorder. Afflicted persons cannot produce clotting factors, which causes people w/ hemophilia to bleed for longer periods of time than people whose produce clotting factors. The main problem w/ hemophilia is internal bleeding, mainly into muscles & joints.

Circulatory System Diseases 3. Atherosclerosis- “plaque” (fat) build up on the inner walls of arteries. 4. Arteriosclerosis: arteries become hard & brittle because calcium is deposited in their walls. Vessels become thickened & lose elasticity. Blood pressure increases & blood clots may form 5. Stroke: blood clot blocks artery or a blood vessel breaks, interrupting blood flow to an area of the brain. Brain cells begin to die & abilities controlled by that area of the brain are lost.

6. Aneurysms A ballooned bulge in a blood vessel caused by disease or weakening of vessel wall. –Usually found in artery at base of brain or in the aorta –If these rupture then will lead to hemorrhaging and death

Blood, Blood vessels (smooth muscle) heart circulatory Red & white blood cells

Interactions Among Systems to Achieve Nutrient Absorption Nutrients are obtained from food that the digestive system has broken down. The respiratory system obtains oxygen from the atmosphere. These nutrients are transported by the circulatory system to cell of the body for absorption.