Chapter 5 – Cardiovascular System: Heart and Blood Vessels
5.1 Overview of the Cardiovascular System
5.2 The Types of Blood Vessels
5.3 The Heart Is a Double Pump
5.4 Features of the Cardiovascular System
5.5 Two Cardiovascular Pathways
5.6 Exchange at the Capillaries
5.7 Cardiovascular Disorders
Chapter 6 – Cardiovascular System: Blood
6.1 Blood: An Overview
6.2 Red Blood Cells and Transport of Oxygen
6.3 White Blood Cells and Defense Against Disease
6.4 Platelets and Blood Clotting
6.5 Blood Typing and Transfusions
6.6 Homeostasis
Chapter 7 – Lymphatic System and Immunity
7.1 Microbes, Pathogens, and You
7.2 The Lymphatic System
7.3 Nonspecific Defenses
7.4 Specific Defenses
7.5 Acquired Immunity
7.6 Hypersensitivity Reactions
Chapter 8 – Digestive System and Nutrition
8.1 Overview of Digestion
8.2 First Part of the Digestive Tract
8.3 The Stomach and Small Intestine
8.4 Three Accessory Organs and Regulation of Secretions
8.5 The Large Intestine and Defecation
8.6 Nutrition and Weight Control
Major Topic I – Oxygen/Microbes/Immunity
Chapter 5 – Cardiovascular System: Heart and Blood Vessels
5.1 Overview of the Cardiovascular System
The cardiovascular system consists of the heart and blood vessels. The heart pumps blood to all parts of our body. The heart is an incredible machine that adapts and responds to our bodies needs on a cellular level. If our body requires more oxygen during exercise, the heart responds by beating faster to move oxygenated blood more quickly to each cell in our bodies. Amazing! Blood vessels take blood to and from the capillaries. In the capillaries, the exchange of nutrients for wastes occurs. Blood is recharged with oxygen at the lungs, is filled with nutrients at the digestive tract, and wastes are removed from the blood in the kidneys.
5.2 The Types of Blood Vessels
Arteries and arterioles take blood away from the heart. In pictures, arteries and arterioles are depicted as red because the blood in them is filled with O2. Arteries have the thickest walls which allow them to withstand blood pressure. The capillaries are where exchange of substances occurs. Veins and venules take blood to the heart. In pictures, veins and venules are depicted as blue because the O2 in the blood has been depleted and is traveling towards the lungs for a recharge. Veins have relatively weak walls with valves that keep the blood flowing in one direction.
5.3 The Heart Is a Double Pump
The heart is cone shaped and is located in your chest, between your lungs and behind your sternum. It has a right and left side. The two sides are separated with a wall called a septum. Each side of the heart has an atrium and a ventricle. The major portion of the heart is called the myocardium, which consists mainly of tight muscle fibers that are branched together. The heart is protected and supported by a thick membranous sac called the pericardium. Valves keep the blood moving in the correct direction.
Passage of blood through the heart: The atrium received O2 deficient blood from the body, and the ventricle pumps it into the pulmonary circuit to the lungs. The atrium receives O2 rich blood from the lungs, and a ventricle pumps it into the systemic circuit.
The heart beat is controlled: During the cardiac cycle, the SA node initiates the heartbeat by causing the atria to contract. The AV node conveys the stimulus to the ventricles, causing them to contract. The working phase – the contraction of the atria and ventricles is called systole. The relaxing of the chambers is called diastole. The heart sounds are due to the closing on the atrioventricular valves, followed by the closing on the semilunar valves. This all occurs in the heart itself. It is so amazing! The heartbeat can also be controlled by the medulla oblongata.
5.4 Features of the Cardiovascular System
Pulse – the pulse rate indicates the heartbeat rate. The pulse is measured by counting how many beats are heard in one minute.
Blood pressure – the pressure of blood against the wall of a blood vessel. The highest arterial pressure, called the systolic pressure is measured as blood leaves the heart. The lowest pressure, called the diastolic pressure, is measured while the heart ventricles are relaxed. The reduced velocity of blood flow in capillaries facilitates exchange of nutrients and wastes in the tissues. Blood flow in veins is caused by skeletal muscle contraction, the presence of valves, and respiratory movements.
5.5 Two Cardiovascular Pathways
The cardiovascular system is divided into the pulmonary circuit and the systemic circuit. In the pulmonary circuit, blood travels to and from the lungs. In the systemic circuit, the aorta (the largest artery in the circuit) divides into blood vessels that serve the body’s organs and cells. The superior and inferior venae cavae (the largest veins in the circuit) return O2 deficient blood to the heart.
5.6 Exchange at the Capillaries
There are two forces that cause the movement of fluid through capillary walls: blood pressure and osmotic pressure. At the arterial end of the cardiovascular capillary, blood pressure is greater than osmotic pressure, so water leaves the capillary. In the midsection, oxygen and nutrients diffuse out of the capillary, while carbon dioxide and other wastes diffuse into the capillary. At the venous end, osmotic pressure created by the presence of proteins is greater than blood pressure, causing water to enter the capillary. The fluid that is not picked up at the venous end of the cardiovascular capillary is excess tissue fluid. It enters the lymphatic capillaries. Lymph is tissue fluid contained within lymphatic vessels. The lymphatic system is a one-way system, and fluid is returned to blood when it reaches the subclavian veins (under your collarbone, or clavicle).
5.7 Cardiovascular Disorders
Cardiovascular disease is the leading cause of death in the Western countries. Hypertension and atherosclerosis can lead to stroke, heart attack, or an aneurysm. Following a heart-healthy diet, getting regular exercise, maintaining a proper weight, and not smoking are protective against cardiovascular disease.
Chapter 6 – Cardiovascular System: Blood
6.1 Blood: An Overview
Blood is the primary transport medium. It is the reason all of our other organs can function because it transports all the required nutrients to them and removes all waste.
The functions of blood are:
Transports hormones, oxygen and nutrients to cells
Transports carbon dioxide and other wastes from cells
Fights infections and has various regulatory functions
Maintains blood pressure
Regulates body temperature and
Keeps the pH of body fluids within normal limits
All of these functions help maintain homeostasis. Blood has two main components called formed elements and plasma. The formed elements are red blood cells, white blood cells and platelets.
The makeup of plasma:
91% of blood plasma is water
Plasma proteins are mostly produced by the liver
Plasma proteins maintain osmotic pressure, help regulate pH, and transport molecules
Some functions of plasma proteins are transport, immunity and blood clotting.
6.2 Red Blood Cells and Transport of Oxygen
Red blood cells are specialized for the O2 they carry. They are small, bi-concave disks that lack a nucleus and contain hemoglobin, which combines with oxygen and transports it to the tissues. Hemoglobin is a pigment that makes the cells and blood a red color. The globin portion of hemoglobin is a protein that contains four highly folded polypeptide chains. The heme part of hemoglobin is an iron-containing group in the center of each polypeptide chain. This allows the red blood cells to accept billions of copies of O2 molecules from the lungs and then release them into the tissues. Red blood cell production is controlled by the oxygen concentration decreases, the kidneys increase their production or erythropoietin, and more red blood cells are produced.
6.3 White Blood Cells and Defense Against Disease
White blood cells are larger than red blood cells. They have a nucleus and are translucent because they lack hemoglobin. White blood cells fight infection, and are an important part of the immune system. White blood cells are either granular leukobytes or agranular leukocytes. The granular leukocytes are eosinophils, basophils, and neutrophils.
Neutrophils are abundant and respond first to infections. They phagocytize pathogens. Sometimes their death is large numbers results in pus. Neutrophils are the most abundant of white blood cells. They account for 50-70% of all white blood cells.
Not much is known about the function of eosinophils, but they increase in number in the event of a parasitic worm infection or an allergic reaction.
Basophils release histamine which dilates blood vessels, but constricts air tubes that lead to the lungs. This is associated with allergic reations.
The agranular leukocytes include monocytes and lymphocytes.
Lymphocytes account for 25-35% of all white blood cells and are the second most abundant type of white blood cells. They are responsible for immunity against poisonous substances. Lymphocytes are classified as either B cells or T cells. The B cells produce antibodies that combine with target pathogens and mark them for destruction. T cells directly destroy pathogens. The AIDS virus attacks one type of T cell causing immune deficiency.
Monocytes are the largest of the white blood cells. They can become macrophages that phagocytize pathogens and cellular debris. They basically suck up all the junk. All blood cells are produced within red bone marrow from stem cells. They live about 120 days and are eventually destroyed in the liver and spleen.
6.4 Platelets and Blood Clotting
Platelets result from fragmentation of megakaryocytes in the red bone marrow and are produced at a rate of 200 billion a day. Platelets function in blood clotting. Platelets and two plasma proteins, prothrombin and fibrinogen, function in blood clotting, and enzymatic process that results in fibrin threads, which trap red blood cells. These are fancy ways to describe a scab forming.
6.5 Blood Typing and Transfusions
Blood typing usually involves determining the ABO blood group and whether the person is Rh- or Rh+. Determining blood type is necessary for transfusions so that agglutination of red blood cells does not occur.
ABO blood typing determines the presence of absence of type A antigen and type B antigen on the surface of red blood cells.
Type A surface antigens; plasma has anti-B antibodies.
Type B surface antigens; plasma has anti-A antibodies
Type AB surface antigens; plasma has neither antibodies
Type O – neither type A nor type B surface antigens. Plasma has both anti-A and anti-B antigens
Agglutination occurs if the corresponding antigen and antibody are put together.
The Rh antigen must also be considered when transfusing blood, and it is very important during pregnancy because and Rh- mother may form antibodies to the Rh antigen while carrying or after the birth of an Rh+ child. These antibodies can cross the placenta to destroy the red blood cells of any subsequent Rh+ child.
My blood type is A+. I am a regular blood donor, and I marvel at the art and science of it. Since I meet the height and weight requirements for the double red donation, that is what I normally do. It is different from regular donation because as your blood leaves your body, it is directed into a centrifuge machine where the red blood cells are separated from the plasma. Two bags hang and you can watch one fill with plasma and the other fill with red blood cells. The machine cycles the plasma back into your vein in intervals. A blood thinner is added to the plasma to prevent any thickening during the process. Donating in this way allows the body to give two pints of blood instead of just one since the plasma is being returned. The double red also leaves the donor feeling much less fatigue and dizziness than with a normal donation since the body is not being deprived of the fluid.
6.6 Homeostasis
Homeostatis depends upon the cardiovascular system because it serves the needs of the cells. Several other body systems are also critical to cardiovascular system function:
The digestive system supplies nutrients
The respiratory system supplies oxygen and removes carbon dioxide from the blood
The nervous and endocrine systems are involved in maintaining blood pressure
The lymphatic system returns tissue fluid to the veins.
Skeletal muscle contraction and breathing movements propel blood in the veins.
Chapter 7 – Lymphatic System and Immunity
7.1 Microbes, Pathogens, and You
Microbes perform valuable services. They contribute to the creation of yogurts, cheeses, beers (yea!!) and breads. It also helps by decomposing things that die. Everything would cease to exist without bacteria. Though bacteria are helpful, they also cause disease. Bacteria and viruses are also called pathogens.
Bacteria are prokaryotic cells that live and reproduce independently of host cells and cause disease by multiplying in hosts and also by producing toxins.
Viruses are non-cellular particles, consisting of a protein coat and a nucleic acid core. They take over the machinery of the host in order to reproduce and can emerge and cause new diseases the human body has difficulty combating.
7.2 The Lymphatic System
The lymphatic system consists of lymphatic vessels that return excess fluid in the tissues to cardiovascular veins. The primary lymphatic organs are the red bone marrow, where all blood cells are made and the B lymphocytes mature and the thymus gland, where T lymphocytes mature. The secondary lymphatic organs are the spleen, lymph nodes, ant other organs such as the tonsils, Peyer’s patches, and the appendix. Blood is cleansed of pathogens and debris in the spleen. Lymph is cleansed of pathogens and debris in the nodes.
7.3 Nonspecific Defenses
Immunity involves nonspecific and specific defenses. The nonspecific defenses include:
Barriers to entry
The inflammatory reaction, which involves the phagocytic neutrophils and macrophages
Protective proteins
7.4 Specific Defenses
Specific defenses require B cells and T cells, also called B lymphocytes and T lymphocytes.
B Cells and Antibody –Mediated Immunity
Activated B cells undergo clonal selection with production of plasma cells and memory B cells, after their B-cell receptor combines with a specific antigen.
Plasma cells secrete antibodies and eventually undergo apoptosis. Plasma cells are responsible for antibody-mediated immunity.
An antibody is usually a Y-shaped molecule that has two binding sites for a specific antigen.
Memory B cells remain in the body and produce antibodies if the same antigen enters the body at a later date.
T Cells and Cell-Mediated Immunity
For a T cell to recognize an antigen, the antigen must be presented by an antigen-presenting macrophage, along with an HLA.
Activated T cells undergo clonal expansion until the illness has been stemmed. Then, most of the activated T cells undergo apoptosis. A few cells remain, however, as memory T cells.
The two types of T cells are cytotoxic T cells and helper T cells.
Cytotoxic T cells kill virus-infected cells or cancer cells on contact because they bear a nonself protein.
Helper T cells produce cytokines and stimulate other immune cells.
7.5 Acquired Immunity
Active immunity can be induced by vaccines when a person is well and in no immediate danger of contracting an infectious disease. Active immunity depends upon the presence of memory cells in the body.
Passive immunity is needed when an individual is in immediate danger of succumbing to an infectious disease administered to, and not made by, the individual.
Monoclonal antibodies, which are produced by the same plasma cell, have various functions, from detecting infections to treating cancer.
Cytokines, including interferon, are a form of passive immunity used to treat AIDS and to promote the body’s ability to recover from cancer.
7.6 Hypersensitivity Reactions
Allergic responses occur when the immune system reacts vigorously to substances not normally recognized as foreign.
Immediate allergic responses, usually consisting of cold-like symptoms, are due to the activity of antibodies.
Delayed allergic responses, such as contact dermatitis, are due to the activity of T cells.
Tissue rejection occurs when the immune system recognized a tissue as foreign.
Autoimmune disorders occur when the immune system reacts to tissues/organs of the individual as if they were foreign.
Major Topic II – Nutrition
Chapter 8 – Digestive System and Nutrition
8.1 Overview of Digestion
The organs of the digestive system are located within the GI tract. The processes of digestion require ingestion, digestion, movement, absorption, and elimination. All parts of the tract have four layers, called the mucosa, submucosa, muscularis, and serosa.
8.2 First Part of the Digestive Tract
In the mouth, teeth chew the food, saliva contains salivary amylase for digesting starch, and the tongue forms a bolus for swallowing.
The air passage and food passages cross in the pharynx. During swallowing, the air passage is blocked off by the soft palate and epiglottis; food enters the esophagus; and restalsis begins. The esophagus moves food to the stomach rhythmic contractions called peristalsis.
8.3 The Stomach and Small Intestine
The stomach expands and stores food and also churns, mixing food with the acidic gastric juices. This juice contains pepsin, and enzyme that digests protein. The stomach expands to a capacity of approximately 1 liter. It is filled with gastric pits which lead to bile ducts.
The duodenum of the small intestine receives bile from the liver and pancreatic juice from the pancreas. Bile emulsifies fat and readies it for digestion.
The pancreas produces enzymes that digest starch, protein and fat. The intestinal enzymes finish the process of chemical digestion.
Small nutrient molecules are absorbed at the villi in the walls of the small intestine.
8.4 Three Accessory Organs and Regulation of Secretions
Three accessory organs of digestion send secretions to the duodenum via ducts. These organs are the pancreas, liver and gall bladder.
The pancreas produces pancreatic juice, which contains digestive enzymes for carbohydrate, protein, and fat.
The liver produces bile, destroys old blood cells, detoxifies blood, stores iron, makes plasma proteins, stores glucose an glycogen, breaks down glycogen to glucose, produces urea, and helps regulate blood cholesterol levels.
The gallbladder stores bile, which is produced by the liver.
The secretions of digestive juiced are controlled by the nervous system and by hormones.
Gastrin produced by the lower part of the stomach stimulates via the bloodstream the upper part of the stomach to secrete pepsin.
Secretin and CCK produced by the duodenal wall stimulate the pancreas to secrete its juices and the gallbladder to release bile.
8.5 The Large Intestine and Defecation
The large intestine consists of the cecum, the colon (including the ascending, transverse, and descending colon), and the rectum, which ends at the anus. The large intestine is larger is diameter than the small intestine, but shorter in length.
The large intestine absorbs water, salts, and some vitamins; forms the feces; and carries out defecation.
Disorders of the large intestine include diverticulosis, irritable bowel syndrome, inflammatory bowel disease, polyps, and cancer.
8.6 Nutrition and Weight Control
The nutrients released by the digestive process should provide us with adequate energy, essential amino acids and fatty acids, and all necessary vitamins and minerals. Today, obesity is on the increase, possibly because people eat too much food and make improper choices of food. Obesity is associated with many illnesses, including diabetes type 2 and cardiovascular disease. The food guide pyramid shows food to emphasize and food to minimize for good health.
Carbohydrates are necessary in the diet, but simple sugars and refined starches cause a rapid release if insulin that can lead to diabetes type 2.
Proteins supply essential amino acids.
Unsaturated fatty acids, particularly the omega-3 fatty acids, are protective against cardiovascular disease.
Saturated fatty acids lead to plaque, which occludes blood vessels.
Vitamins and minerals are also required by the body in certain amounts.
