The Heart and It's Working
The veins walls are considerably thinner in comparison to arterial walls. The larger veins have a system of internal one-way valves which do not allow the blood from flowing downward under the pull of gravity when person stands up. When a human being makes movement, the veins get squeezed by the surrounding muscle that helps in moving more blood towards the heart. Without valves in the veins, blood would move in the legs, which would then be continuing to grow.
The Pulmonary Circulation
The most important function of the pulmonary circulation is to transfer oxygen to the blood and free it from carbon dioxide. This task is completed when the blood flows through the lungs. The pressure at this part of the system is only about one-sixth as great as in the systemic circulation, and the pulmonary arteries walls and veins are thinner in comparison to the walls of other vessels in the rest of the body. In the pulmonary circulation, the role of arteries and veins are the opposite of what they do in the systemic circulation. Blood in the arteries has lesser oxygen, while blood in the veins has higher oxygen. The circuit starts with the pulmonary artery, which extends from the right ventricle and brings blood with low level oxygen content to the lungs. In the lungs, it branches off into the two different arteries, one for each lung, and then into arterioles and capillaries. The gas exchange between the air we breathe in and the blood takes place in the pulmonary capillaries. Pulmonary Capillaries walls work like filters by permitting molecules of gas to pass through but not to molecules of fluid. The total surface area of the capillaries in the lungs ranges from around 500 to 1,000 square feet.
Control of Cardiothe
Blood Vascular function
Blood is a life-saving fluid which helps to maintain an optimum environment in the body by providing a regular supply of nutrients from the outer world and removing waste products from the tissues present in body. Its cells are produced in the bones marrow, primarily in the flat bones like the ribs and the breastbone. The volume of blood in an average adult human being amounts to around 10.5 pints.
Types of Blood Cells
The blood has two main components:
· Cells of several types
· Plasma solution, in which the cells are suspended.
The vast majority of blood cells are erythrocytes (red blood cells), which exceeds in number with white blood cells by about 700 to 1 in the healthy adult human being. The major function of the red blood cells is to transport oxygen. They contain a complex protein arranged around iron that carries oxygen and releases it whenever needed known as the red pigment hemoglobin. Red cells are smaller in comparison to white cells and live only for three to four months. These are generated at a rate of around 8 million in a second to maintain the supply regularly.
The white blood cells are known as leukocytes. There are several types, which differ in shape and size, but all of them share the same function of defending the body against a wide range of invading organisms. These are produced in increased amounts in response to any infection. The platelets are plate-shaped disks which together with special substances in the plasma, trigger the blood-clotting mechanism and prevent an uncontrollable loss of blood when the vessels are not working properly or they are damaged.
The Plasma
Plasma fluid is yellowish in color which consists of 90% water and various other salts like glucose, cholesterol, proteins and others. Proteins in the plasma perform different kind of functions like from transporting molecules of nutrients to acting as antibodies in the immune response. The cardiovascular system plays a most important role in maintaining homeostasis—which is a stable environment inside the body. It can carry out, or make other systems to carry out, rapid short-term adjustments according to demands placed on the body by various human activities and changes in external conditions. For an example, when blood supply to any particular area increases, the flow of blood to other organs must be reduced, or else the cardiac output must be increased. Throughout these changes, blood pressure must remain in the constant state to maintain the vital functions of all the body tissues. To make the adjustments, the cardiovascular system communicates with other body organs through a complex network of monitoring and signaling mechanisms. It transfers signals about its condition and, in return, receives messages to control its performance.
The two main regulatory centers of cardiovascular function are:
· Nervous system
· Kidneys
The Nervous System
The nervous system parts like brain and others constantly monitor and maintain the heart and its circulation. They receive information about the cardiovascular system through number of receptors which generate coded impulses describing about the body's internal environment. Different types of receptors transmit information about the stretching of the arterial walls and the changes in blood pressure. When a person stands up suddenly and blood pressure begins to decrease, their receptors sense a lack of pressure and transmits signals to the heart to beat faster and the blood vessels to constrictor narrow down so that adequate blood pressure can be controlled.
The Heart and Circulation
In result to changes occurred, the nervous system gives adjustment commands. So, if the receptors find a decrease in oxygen and an increase in carbon dioxide in the blood, the brain issue a command to the respiratory center to increase the rate of respiration, which in response delivers more oxygen to the lungs. At the same time, the brain issues generates and accelerate the heart rate and on strict the veins. This transmits more blood to the lungs for the purification. In response, an adequate supply of oxygen to body tissues is ensured. Communications between the nervous and cardiovascular systems are relayed by chemicals known as neurotransmitters. These are the chemicals which travel between cells and can provoke a response in the targeted tissue. The neurotransmitter norepinephrine can increase the heart bit and force of contractions, as well as constriction of the blood vessels. Thus, if we become frightened somehow, more adrenaline is released, more blood is pumped out from the heart to muscles, and we feel better able to run or react if required.
The Kidneys
The kidney plays an important role in the regulation of blood pressure. Because they affect the volume of fluids in the body, they can affect the pressure by making changes in the volume of circulating blood. They release an enzyme known as rennin, which is converted into a powerful blood-pressure-elevating substance and constricts blood vessels and induces sodium and water retention. Delicate mechanisms of kidneys allow them to adjust under different varieties of situations.
The veins walls are considerably thinner in comparison to arterial walls. The larger veins have a system of internal one-way valves which do not allow the blood from flowing downward under the pull of gravity when person stands up. When a human being makes movement, the veins get squeezed by the surrounding muscle that helps in moving more blood towards the heart. Without valves in the veins, blood would move in the legs, which would then be continuing to grow.
The Pulmonary Circulation
The most important function of the pulmonary circulation is to transfer oxygen to the blood and free it from carbon dioxide. This task is completed when the blood flows through the lungs. The pressure at this part of the system is only about one-sixth as great as in the systemic circulation, and the pulmonary arteries walls and veins are thinner in comparison to the walls of other vessels in the rest of the body. In the pulmonary circulation, the role of arteries and veins are the opposite of what they do in the systemic circulation. Blood in the arteries has lesser oxygen, while blood in the veins has higher oxygen. The circuit starts with the pulmonary artery, which extends from the right ventricle and brings blood with low level oxygen content to the lungs. In the lungs, it branches off into the two different arteries, one for each lung, and then into arterioles and capillaries. The gas exchange between the air we breathe in and the blood takes place in the pulmonary capillaries. Pulmonary Capillaries walls work like filters by permitting molecules of gas to pass through but not to molecules of fluid. The total surface area of the capillaries in the lungs ranges from around 500 to 1,000 square feet.
Control of Cardiothe
Blood Vascular function
Blood is a life-saving fluid which helps to maintain an optimum environment in the body by providing a regular supply of nutrients from the outer world and removing waste products from the tissues present in body. Its cells are produced in the bones marrow, primarily in the flat bones like the ribs and the breastbone. The volume of blood in an average adult human being amounts to around 10.5 pints.
Types of Blood Cells
The blood has two main components:
· Cells of several types
· Plasma solution, in which the cells are suspended.
The vast majority of blood cells are erythrocytes (red blood cells), which exceeds in number with white blood cells by about 700 to 1 in the healthy adult human being. The major function of the red blood cells is to transport oxygen. They contain a complex protein arranged around iron that carries oxygen and releases it whenever needed known as the red pigment hemoglobin. Red cells are smaller in comparison to white cells and live only for three to four months. These are generated at a rate of around 8 million in a second to maintain the supply regularly.
The white blood cells are known as leukocytes. There are several types, which differ in shape and size, but all of them share the same function of defending the body against a wide range of invading organisms. These are produced in increased amounts in response to any infection. The platelets are plate-shaped disks which together with special substances in the plasma, trigger the blood-clotting mechanism and prevent an uncontrollable loss of blood when the vessels are not working properly or they are damaged.
The Plasma
Plasma fluid is yellowish in color which consists of 90% water and various other salts like glucose, cholesterol, proteins and others. Proteins in the plasma perform different kind of functions like from transporting molecules of nutrients to acting as antibodies in the immune response. The cardiovascular system plays a most important role in maintaining homeostasis—which is a stable environment inside the body. It can carry out, or make other systems to carry out, rapid short-term adjustments according to demands placed on the body by various human activities and changes in external conditions. For an example, when blood supply to any particular area increases, the flow of blood to other organs must be reduced, or else the cardiac output must be increased. Throughout these changes, blood pressure must remain in the constant state to maintain the vital functions of all the body tissues. To make the adjustments, the cardiovascular system communicates with other body organs through a complex network of monitoring and signaling mechanisms. It transfers signals about its condition and, in return, receives messages to control its performance.
The two main regulatory centers of cardiovascular function are:
· Nervous system
· Kidneys
The Nervous System
The nervous system parts like brain and others constantly monitor and maintain the heart and its circulation. They receive information about the cardiovascular system through number of receptors which generate coded impulses describing about the body's internal environment. Different types of receptors transmit information about the stretching of the arterial walls and the changes in blood pressure. When a person stands up suddenly and blood pressure begins to decrease, their receptors sense a lack of pressure and transmits signals to the heart to beat faster and the blood vessels to constrictor narrow down so that adequate blood pressure can be controlled.
The Heart and Circulation
In result to changes occurred, the nervous system gives adjustment commands. So, if the receptors find a decrease in oxygen and an increase in carbon dioxide in the blood, the brain issue a command to the respiratory center to increase the rate of respiration, which in response delivers more oxygen to the lungs. At the same time, the brain issues generates and accelerate the heart rate and on strict the veins. This transmits more blood to the lungs for the purification. In response, an adequate supply of oxygen to body tissues is ensured. Communications between the nervous and cardiovascular systems are relayed by chemicals known as neurotransmitters. These are the chemicals which travel between cells and can provoke a response in the targeted tissue. The neurotransmitter norepinephrine can increase the heart bit and force of contractions, as well as constriction of the blood vessels. Thus, if we become frightened somehow, more adrenaline is released, more blood is pumped out from the heart to muscles, and we feel better able to run or react if required.
The Kidneys
The kidney plays an important role in the regulation of blood pressure. Because they affect the volume of fluids in the body, they can affect the pressure by making changes in the volume of circulating blood. They release an enzyme known as rennin, which is converted into a powerful blood-pressure-elevating substance and constricts blood vessels and induces sodium and water retention. Delicate mechanisms of kidneys allow them to adjust under different varieties of situations.