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Nature’s Highway “THE BASICS OF THE CIRCULATORY SYSTEM” By:Tarun Gunnabathula, Aditya Bhavikati, And Akshat Sharma

description

Learn everything that you need to know about the circulatory system and all of its various components.

Transcript of Nature's highway

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Nature’s Highway

“THE BASICS OF THE CIRCULATORY SYSTEM”

By:Tarun Gunnabathula, Aditya Bhavikati, And Akshat Sharma

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Read and analyze the information in this book about the circulatory system. In this book you will read about the components of the circulatory system and how it processes and interacts with the other systems located throughout the human body.

PREFACE

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CIRCULATORY SYSTEM

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CHAPTER 1

! In humans heart is divided in four chambers-upper left and right Atria and lower left and right Ventricles. The deoxygenated blood enters from the Superior Vena Cava, into the right Atrium. The blood then passively falls into the right Ventricle. The right Ventricle will then fill up with blood until it is full, and the heart

pumps this blood into the Pulmonary Artery where the blood will go to be oxygenated in the lungs. At the same time, Oxygenated blood ar-rives from the lungs through the Pulonary Vein, and falls into the left Atrium. The blood then seeps through the one way valve into the left Ven-tricle, until it is full. Then the heart pumps it out

Chapter 1 Objective

1. To understand how the heart pumps blood.

2. To understand components of the heart

3. To learn what capillaries are4. To understand cardiac

muscle

The Heart and Capillaries

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into the Aorta and to the rest of the body. This all happens in a split second and what creates the lub-dub sound that we hear and that we call the heart beat.

Capillaries are microscopic blood vessels that connect small arter-ies and small veins. Substances move in and out the capillary walls. Of all the blood vessels, capallaries are the only ones that have walls that are thin enough to allow the exchange of the materi-als between the cells and the blood. The extensive branching pro-vides a sufficient surface area for the cells to pick up and deliver the substances to all the cells in the body. Capillaries are extremely small. Despite the fact that there are approximately 40 billion capil-laries in the body, they hold only 5 % of the the total blood volume in the body. The size of capillaries is approximately 5-10 nanometer in size. Capillaries are essential for the delivery of oxygen in the tis-sues and the exchange of nutrients between blood and interstitial fluid surrounding the cells. This function is well supported by the anatomy of the vessels. The thin walls of the capillaries are com-posed of a single layer of endothelial cells. As a result, gasses such as oxygen and carbon dioxide can diffuse through their walls, as can lipid soluble substances. In contrast, an exchange of lipid-insoluble substances occurs via transcytosis, which involves forma-tion of pinocytotic vesicles at one side of the endothelial cell, their transport across the cells, and release of contents from the other side of the cell.

The heart has a special muscle called cardiac-muscle. This muscle is spacial to the heart and can only be found in the heart, hence the name, cardiac. This muscle produces its own electric signal, in or-der for the muscle around the heart to squeeze and release, thus pumping blood. It has similarities with skeletal muscle and with

smooth muscle in that its contractions are not under conscious con-trol. However this type of muscle is highly specialized. It is under the control of the autonomic nervous system, however, even with-out a nervous input contractions can occur due to cells called pace-maker cells. Cardiac muscle is highly resistant to fatigue due to the presence of a larger number of mitochondria, myoglobin and a good blood supply allowing continuous aerobic metabolism. The most muscular part of the heart is its middle layer, called the myo-cardium, which is mainly responsible for the hearts contractions. Even if you isolate these certain cells, they will still have the capa-bility to beat and pump just as if it was in the body.

Additional Information

●! Made of three layers- Epicardium (outer), Myocardium (mid-dle) and Endocardium (inner).

●! Cardiac cells known as cardiomyocytes obtain nutrients and oxygen through coronory arteries

●! Heart beat is generated through specialized conduction sys-tem called the sino-atrial node (SA-node) and atrio-ventricular node (AV-node)

●! In addition to SA node, sympathetic and parasympathetic nerves regulate cardiac rhythm. Activity is increased by sympa-thetic stimulation and diminished via parasympathetic stimulation via vagus nerve.

●! Calcium ions along with troponins are major regulators of car-diac contraction

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●! Heart is prone to several cardiovascular diseases. Examples include coronary artery disease, cardiomyopathy, congestive heart failure, valvular heart disease, heart murmurs, cardiac arrest, cardi-tis, Angina pectoris and cardiac hypertrophy.

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CHAPTER 2

Blood is important and essential for good health, because it supplies the body with a steady amount of oxygen and fuel to reach the billions of cells in the human body. Blood also carries car-bon dioxide and waste materials to their specific organs such as the kidneys and lungs. Blood is also important because we cannot maintain ho-

meostasis without it, fight infections and we wouldn’t be able to get rid of our waste products in our body. There are two types of blood vessels in our body. Blood vessels carry blood through-out our body. The two types are arteries and veins. Arteries carry the oxygenated blood from the heart to the rest of the body. The veins carry

Chapter 2 Objectives

1. To learn the components of blood

2. Function and importance of blood

3. Function of plasma in our blood

Blood

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the deoxygenated blood back to the heart and lungs where the blood is oxygenated. You can feel the blood traveling through your body, because a number of arteries are close to the surface of the body's skin. The blood that travels through the system of veins and arteries is called “whole blood”. “Whole blood” contains three types of blood cells; red blood cells, white blood cells, and plate-lets. Blood cells are produced in the marrow of bones. Bone mar-row is a jellylike material inside the bone that is composed of fat, blood, and special cells that turn into various kinds of blood cells, such as red and white blood cells. The marrow in most of the bones in a child’s body produces blood cells. In the body of an adult, only certain bones make marrow in the body, such as the spine, ribs, pelvis, and a few others. The blood cells travel through the circulatory suspended in plasma. Plasma is a vital liquid that is 92% water and contains nutrients, waste products, proteins, and hormones. Plasma and the three types of blood cells combined are called whole blood.

The components of blood:

Red Blood Cells:

Red blood cells are known as erythrocytes. The human body con-tains nearly 25 trillion red blood cells. There are approximately 5 million red blood cells in a microliter of blood. The structure of a red blood cell allows it to transport oxygen from the lungs to body tissue. Red blood cells are very small and have a diameter of ap-proximately 6 nanometers. Red blood cells are disk shaped. Red blood cells have a small depression on either side to catch more oxygen. The size of the red blood cells allows them to go through capillaries. The small size of the red blood cells allows a greater dif-

fusion of oxygen across the blood cells’ plasma membranes than if the cells were larger. Because blood contains so many of these small cells, the combined surface area of these many blood cells translates into an extremely large amount of surface area for the dif-fusion of oxygen. The disk shape and the depressions on either side also contribute to a greater surface area. Red blood cells are un-usual in that they do not contain nuclei or mitochondria, the cellu-lar organelle in which aerobic metabolism (the breakdown of nutri-ents that requires oxygen) is carried out. Instead, red blood cells ac-quire energy through metabolic processes that do not require oxy-gen. The lack of nuclei and mitochondria therefore allow the red blood cell to function without depleting its cargo of oxygen, leav-ing more oxygen for the body tissues. The molecule that binds oxy-gen in red blood cells is called hemoglobin. Hemoglobin is large, globular protein consisting of protein chambers surrounding an iron core. A red blood cell contains about 250 molecules of hemo-globin. In the lungs, oxygen diffuses across the red blood cell mem-brane and binds to hemoglobin. As blood circulates to the tissues, oxygen diffuses out of the red blood cells and enters tissues. The waste product of aerobic metabolism, carbon dioxide, then diffuses across red blood cells and binds to hemoglobin. Once circulated back to the lungs, the red blood cells discharge their load of carbon dioxide, which is then breathed out of the lungs. However, only 7 percent of carbon dioxide generated from metabolism is trans-ported back to the lungs for exhalation by red blood cells; the ma-jority is transported in the form of bicarbonate, a component of plasma. Red blood cells are formed in red bone marrow from pre-cursor cells called pluripotent stem cells. The process of red blood cell formation is called hematopoiesis. The average red blood cell lives 3-4 month. Red blood cells also carry specific proteins called

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antigens that determine blood types. Several blood diseases in-volve red blood cells. Notable examples include, iron deficiency anemia, sickle cell anemia, pernicious anemia, aplastic anemia, red cell aplasia, hemolytic anemia, pernicious anemia thalassemia and the parasitic disease-malaria.

White Blood Cells:

White blood cells are less numerous than red blood cells in the hu-man body. Each microliter in the human body contains about 5,000 to 10,000 white blood cells. The number of white blood cells in-creases, however, when the body is fighting off infection. White blood cells, therefore, are maintained at a stable number until the immune system detects the presence of a foreign invader. When the immune system is activated, chemicals called lymphocytes stimulate the production of more white blood cells. White blood cells function as the body’s defense against invasion against mali-cious substances and are key components of the immune system. They usually do not circulate in the blood vessels, and are instead found in the interstitial fluid and in lymph nodes. Lymph nodes are composed of lymphatic tissue and are located at strategic places in the body. Blood filters through the lymph nodes, and the white cells present in the nodes attack and destroy any foreign in-vaders. The human body contains five types of white blood cells: monocytes, neutrophils, basophils, eosinophil, and lymphocytes. Each type of white blood cell plays a specific role in the body’s im-mune defense system.

All white blood cells arise in the red bone marrow. However, the cells destined to become lymphocytes are first differentiated into lymphoid stem cells in the red bone marrow; from the red bone

marrow, these stem cells undergo further development and matura-tion in the spleen, tonsils, thymus, adenoids, and lymph nodes.

Monocytes, which comprise 3–8 percent of the white blood cells, and neutrophils, which comprise 60–70 percent of white blood cells, are phagocytic cells. They ingest and digest cells, including foreign microorganisms such as bacteria. Monocytes differentiate into cells called macrophages. Macrophages can be fixed in one place, such as the brain and lymph nodes, or can “wander” to ar-eas where they are needed, such as the site of an infection. Neutro-phils have an additional defensive property: they release granules of lysozyme, an enzyme that destroys cells.

Basophils comprise 0.5–1 percent of the total composition of white blood cells and function in the body’s inflammatory response. Al-lergies are caused by an inflammatory response to relatively harm-less substances, such as pollen or dust, in sensitive individuals. When activated in the inflammatory response, basophils release various chemicals that cause the characteristic symptoms of aller-gies. Histamines, for instance, cause the runny nose and watery eyes associated with allergic reactions; heparin is an anticoagulant that slows blood clotting and encourages the flow of blood to the site of inflammation, inducing swelling.

Eosinophils, which comprise 2–4 percent of the total composition of white blood cells, are believed to counteract the effects of hista-mine and other inflammatory chemicals. They also phagocytize bacteria tagged by antibodies.

Lymphocytes, which comprise 20–25 percent of the total composi-tion of white blood cells, are divided into two types: B lympho-cytes and T lymphocytes. The names of these lymphocytes are de-

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rived from their origin. T lymphocytes are named for the thymus, an organ located in the upper chest region where these cells ma-ture; and B lymphocytes are named for the bursa of Fabricius, an organ in birds where these cells were discovered. T lymphocytes play key roles in the immune response. One type of T lymphocyte, the helper T lymphocyte, activates the immune response when it encounters a macrophage that has ingested a foreign microorgan-ism. Another kind of T lymphocyte, called a cytotoxic T lympho-cyte, kills cells infected by foreign microorganisms. B lymphocytes, when activated by helper T lymphocytes, become plasma cells, which in turn secrete large amounts of antibodies.

Platelets:

Platelets are not cells, like red and white blood cells. Platelets are fragments of cells that function in blood clotting. Platelets number about 250,000–400,000 per liter of blood. Blood clotting is a com-plex process that involves a cascade of reactions that leads to the formation of a blood clot. Platelets contain chemicals called clot-ting factors. These clotting factors first combine with a protein called prothrombin. This reaction converts prothrombin to throm-bin. Thrombin, in turn, converts fibrinogen (present in plasma) to fibrin. Fibrin is a thread-like protein that traps red blood cells as they leak out of a cut in the skin. As the clot hardens, it forms a seal over the cut. This process works for relatively small cuts in the skin. When a cut is large, or if an artery is severed, blood loss is so severe that the physical pressure of the blood leaving the body pre-vents clots from forming.

Plasma:

Plasma makes up 55 percent of the blood, while the blood cells con-stitute the other 45 percent. Plasma contains mostly water, which accounts for about 92 percent of the plasma content. The water acts as a solvent (the fraction that compounds can dissolve in) for carry-ing other substances.Proteins account for 7 percent of plasma. The most prevalent of these proteins in plasma is albumin, a protein also found in egg white. Albumin concentration is four times higher in the blood than in the interstitial fluid (the watery fluid that bathes tissues, but is located outside and between cells). This high concentration of albumin in plasma serves an important os-motic function. The higher concentration of protein in blood pre-vents water from moving from the blood into the interstitial fluid. Without this osmotic protection, water would move from the inter-stitial fluid into the blood, diluting the plasma and swelling the blood volume. A high blood volume could have disastrous conse-quences, because the circulatory system can only pump so much blood before it becomes overloaded.

Other proteins that are present in plasma are immunoglobins and fibrinogen. Immunoglobins, also called antibodies, are proteins that function in the immune response. Antibodies attach to invad-ing bacteria and other microorganisms, marking them for destruc-tion by other immune cells. Fibrinogen is a protein that functions in a complex series of reactions that leads to the formation of blood clots.

The other components of plasma are salts, nutrients, enzymes, hor-mones, and nitrogenous waste products. Together, these sub-stances account for 1.5 percent of plasma. The salts present in

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plasma include sodium, potassium, calcium, magnesium, chloride, and bicarbonate. These salts function in many important body proc-esses. For instance, calcium functions in muscle contraction; so-dium, chloride, and potassium function in nerve impulse transmis-sion in nerve cells; and bicarbonate regulates pH. These salts are also called electrolytes. An imbalance of electrolytes, which can be caused by dehydration, can be a serious medical condition. Many gastrointestinal illnesses, such as cholera, cause a loss of electro-lytes through severe diarrhea. When electrolytes are lost, they must be replaced with intravenous solutions of water and salts or by hav-ing the patient drink solutions of salts and water

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CHAPTER 3

Interactions between the skeletal system and circulatory system

The bones in the skeletal system play a vital role in the circulatory system. The bones are very vi-tal to making the blood cells in the circulatory system. The bone marrow in the bones of the skeletal system makes all the red blood cells. The

skeletal system is also very vital for protection and structure. The bones in the skeletal system protect the heart, one of the most vital organs in the body. Without the bones in the body the veins and arteries would not be structured and sturdy.

Chapter 3 Objectives

1. Interactions between the skeletal system and circulatory system

2. Interactions between the Respiratory and Circulatory system

3. Interactions between the Excretory system and Circulatory system

System

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Interactions between the Respiratory and Circulatory system:

! In order for the human body to supply oxygen to the rest of the body, it need to be able to maintain a continuous flow of blood and oxygen to the rest of the body. But in order to achieve this con-tinuous supply, the circulatory system need to be able to work with the respiratory system in order to oxygenate blood.

! When the blood first is pumped to the lungs, when it is lack-ing oxygen, it needs to go through an elaborate process in order to be oxygenated. First, the blood goes to the heart and then meets something called the Avioli in the lungs that are surrounded by capillaries. Avioli are tiny pocket full of air that are surrounded with a thin muscle, and supply the blood with oxygen, and in ex-change the blood gives carbon dioxide which we then breath out. This whole process of exchanging oxygen and carbon dioxide all happens in a split second each time we breath in and out. This ex-change happens in the lungs, where the capillaries make contact with the avioli.

Interactions between the Excretory system and Circulatory sys-tem:

The circulatory system moves the blood around the body. Some of this blood passes through the kidneys, liver, lungs, and skin. Each of these organs performs some waste removal function on the blood. The simple answer would be that the circulatory system pro-vides the excretory system with the blood to be cleaned. One thing that has always bothered me about the excretory system is that there is no system provided to ensure that all blood is cleaned at some point. The body seems to rely on the fact that mixing all the

blood up together and cleaning some of it will make all of it clean enough for re-use.

Sources used:

Bibliography

Scogna, Kathleen. "Blood." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 5th ed. Farmington Hills, MI: Gale, 2014. Science in Context. Web. 29 Mar. 2015.

"Capillaries." The Gale Encyclopedia of Science. Ed. K. Lee Lerner and Brenda Wilmoth Lerner. 5th ed. Farmington Hills, MI: Gale, 2014. Science in Context. Web. 29 Mar. 2015.

Cite this http://kidshealth.org/teen/your_body/body_basics/blood.html#

Bibliography for Images

●! App Icon

○! Dreamstime

○! Image Bought

●! Main page Circulatory Image

○! Dreamstime

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○! Image Bought

■! Too big

●! Main page Red Blood cell

○! http://www.macroevolution.net/ (email permission)

●! Main page White Blood cell

○! Wikimedia

■!http://upload.wikimedia.org/wikipedia/commons/2/24/Red_White_Blood_cells.jpg

●! Main page Platelets

○! Image source

■!http://www.imagesource.com/C.aspx?VP3=SearchResult&VBID=2FABXZZ2K53_R

●! Blood Vessels

○! Wikimedia

■!http://upload.wikimedia.org/wikipedia/commons/thumb/6/61/Blood_vessels.svg/2000px-Blood_vessels.svg.png

●! Heart

○! Nettrekker

○!http://www.hybridmedicalanimation.com/wp-content/uploads/2011/06/interactive-Heart.jpg

●! Red Blood Cell

○! http://www.macroevolution.net/ (email permission)

●! White Blood Cell

○! Dreamstime

○! Image Bought

●! Other Substances in Blood

○! Bought

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