THE CIRCULATORY SYSTEM
Enviado por sofiacelasco0 • 2 de Septiembre de 2018 • Resúmenes • 1.097 Palabras (5 Páginas) • 83 Visitas
BIOLOGY
CIRCULATION
THE CIRCULATORY SYSTEM
Composition: Blood, heart and blood vessels
Function: Transports 7 things:
-Oxygen from the lungs to the cells
-Digested food (nutrients) from small intestine to the cells.
-Removes wastes like carbon dioxide from the cells to the lungs
-Wastes from cells to kidneys (riñones)
-Transports hormones, antibodies (proteinas fabricadas por globulos blancos, que cuando el microvio vuelve a entrar, estos globulos blancos se lo comen) and blood proteins (RH, A+, A-)
BLOOD CIRCULATION
-The heart circulates the blood through the blood vessels
-Blood flow in arteries away from the heart to the different organs of the body
-Blood flows back to the heart in veins
- Capillaries: are the smallest blood vessels that connect arteries to veins
-The circulatory system allows a one-way flow of blood around the body
-The heart pumps blood giving it pressure so that it flows inside arteries and this helps to maintain a one-way flow of blood (this is good for getting blood to the capillaries) but…
-High pressure blood will damage the delicate capillaries, so small muscular blood vessels known as arterioles reduce the pressure before the blood enters the capillaries
-We have valves in our veins to make sure blood does not flow backwards away from the heart
-If this happened, blood would collect in veins, which would swell, preventing proper circulation (semi-lunar valves)
A DOUBLE CIRCULATION
-The heart is divided into 2 halves, right and left
-The septum is a thick wall of muscle that separates these 2 halves of the heart
-Each side has two chambers: an atrium and a ventricle
-The blood flows twice through the heart during one circuit of the body
Function of the septum: to stop blood in the right side of the heart mixing with blood in the left side
Right Side | Left Side |
Pumps blood to the lungs and back to the heart again | Pumps blood to the rest of the body and to the heart again |
Not high pressure required since there is little resistance to flow in the lungs as they are a spongy tissue filled with air (no tiene que hacer mucha presion porque pompea la sangre en la parte esponjosa) | Greater pressure needed since there is much more resistance to flow than there is through the lungs (tiene que llevar la sangre a todo el cuerpo) |
Gas exchange occurs as blood flows through capillaries in the lungs | Gas exchange occurs as blood flows through capillaries in organs like muscles, gut, liver and kidneys |
Blood absorbs oxygen and loses carbon dioxide | Oxygen leaves the blood and carbon dioxide enters |
The blood that flows from the lungs is rich in oxygen and is called OXYGENATED blood | Blood that leaves capillaries and flows through veins contains less oxygen and is called DEOXYGENATED blood |
Bright red colour | Dark red colour. |
HEART STRUCTURE
(drawing of page 102)
HEART ACTION
-The heart pumps blood when its muscles contract
-When the muscles contract, the chamber gets smaller and squeezes the blood out
-After each chamber contracts, it relaxes so it fills up with blood again
Diastole: -Is when the heart muscles are relaxed.
-Blood flows into the atria from the veins
Systole: -Is when the heart muscles contract and force blood into ventricles.
-The valves between the atria and ventricles open due to the pressure of blood against them
-Then the ventricles contract to force blood out into arteries
-The valves close to prevent blood flowing back into the atria
-The right ventricle; pumps blood to the lungs in the pulmonary artery
-The left ventricle; pumps blood to the rest of the body in the aorta(main artery)
-Deoxygenated blood returns to the right atrium in the vena cava
-Oxygenated blood returns to the left atrium in the pulmonary veins
BLOOD VESSELS
Vessel | Organs | |||
Heart | Lungs | Liver | Kidneys | |
Bringing blood to organ | Vena cava to right atrium; pulmonary vein to left atrium | Pulmonary artery | Hepatic artery; hepatic portal vein | Renal artery |
Taking blood away from organ | Pulmonary artery from right ventricle | Pulmonary vein | Hepatic vein | Renal vein |
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