http://science.nationalgeographic.com/science/wallpaper/heart-angiogram.html
Picture of a healthy heart
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
Bioethical Focus pg.101
5.1 Overview of the Cardiovascular System
The heart and the blood vessels make up the cardiovascular system.
In humans there is always blood in the blood vessels
Heart beats pump blood into blood vessels
The purpose of circulation is to bathe the tissue with fluids, (not directly the cell itself).
Circulation of blood removes waste products from tissue fluids and also nourishes the tissue fluids with oxygen and nutrients. Blood must be refreshed to be able to perform circulation. Blood is refreshed in the lungs, the intestines, and the kidneys.
Lungs: carbon dioxide is removed and oxygen enters
Kidneys: blood is purified of waste material and water and salts are retained
Intestines: nutrients enter here
The liver (largest organ) takes up amino acids and returns proteins in the blood, which assists in transportation of fats.
The liver also removes any toxins that have entered the blood at the intestines.
1-Blood moves through vessels as the heart contracts and generates blood pressure.
2-Blood vessels transport blood, from heart, to arteries, capillaries, and veins, then returns to the heart.
3-Exchanges at capillaries refresh the blood then tissue fluid (interstitial fluid).
4-As needed by the body, heart and blood vessels regulate the blood flow.
The Lymphatic System
The lymphatic system assists the cardiovascular system by collecting excess tissue fluid and returning it.
When fluid enters the lymphatic vessels it is called �lymph�.
Lymph and Blood are both considered �fluid tissues�.
5.2 The Types of Blood Vessels
1-Arteries (from the heart) The arterial wall has three layers. Arterioles are very small arteries that either dilate or restrict to regulate the blood pressure.
5.3 The Heart Is a Double Pump
santacruz.indymedia.org "your heart is the size of a fist"
-The largest part of the heart is cardiac muscle tissue called, Myocardium.
-The heart is surrounded by Pericardium, which is a thick sac that protects and supports the heart.
-The Septum wall separates the heart into a left and right side.
1-Right Atrium-located in the upper portion
2-Left Atrium-located in the upper portion
3-Right Ventricle-located in the lower portion
4-Left Ventricle-located in the lower portion
Atrioventricular valves (AV) lie between the atria and the ventricles.
Support for these valves come from fibrous strings called chordae tendinae.
The AV on the right is called the Tricuspid and the AV on the left is called the bicuspid (or the mitral valve).
The other two valves are called the Semi-lunar valves.
This is how blood passes through the heart:
-The superior vena cava and the inferior vena cava enter the right atrium.
-The right atrium sends blood to the right ventricle.
-The right ventricle sends blood through the pulmonary semi lunar valve into pulmonary trunk-which divides into two pulmonary arteries and into the lungs.
-Four pulmonary veins enter the left atrium.
The left ventricle sends blood through aortic semi lunar valve into aorta to the blood proper.
O2 poor blood and O2 rich blood never mix due to the way blood passes through the heart. Blood must pass through the lungs to get from the right side to the left side. The heart is a double pump. It sends blood through the lungs from the right ventricle and blood throughout the body from the left ventricle. The left ventricle has a more difficult job. The pumping heart sends blood out under pressure to the arteries. The blood pressure is greater in the aorta because the left side of the heart is the stronger side. Blood pressure decreases as cross-sectional arteries and arterioles increases.The Heartbeat is Controlled
1-Every heartbeat is called a Cardiac Cycle.
2-Systole refers to contraction of the chambers * this is the working phase
3-Diastole refers to relaxation of the chambers * this is the resting phase
4-Contractions (heartbeats) approximately 70 times a minute.
The rhythmical contractions occurs because of the (intrinsic) internal conduction system.
Signal is sent to Atrioventricular bundle, then branches to the Purkinje fibers where the intercalated disks allow the electrical current to flow from cell to cell.
External Control of Heartbeat
The body has an (extrinsic) external way of regulating the heartbeat.
The Medulla Oblongata is the cardiac control center and is located in the brain.
With the parasympathetic and sympathetic parts of the nervous system, the beat of a heart can be altered.
The parasympathetic promotes resting and the sympathetic promotes �fight or flight� responses.
There are two hormones which are released by the adrenal medulla, that also stimulate the heart: (1) Epinephrine (2) Norepinephrine
1-Left ventricle contracts-
2-Pressurized blood sent to aorta-
3-Progressive decrease in blood pressure as blood moves through arteries, arterioles, capillaries, venues, and the veins.
4-The rhythmic expansion/recoil of arterial wall is felt in the body as a pulse-
5-Homeostasis can occur because the beating heart creates pressure to propel blood flow into the arteries and arterioles. The arterioles lead to capillaries where exchange with tissue fluid occurs.
Blood Pressure is the pressure of blood against the wall of a blood vessel.
Sphygmomanometer is an instrument used to measure blood pressure.
Systolic Pressure-highest arterial pressure which is reached during ejection of blood from heart-
Diastolic Pressure-lowest pressure occurs while heart ventricles are relaxing-
Normal �resting� BP for a young adult is 120/80.
High BP is called �Hypertension�
Low BP is called �Hypotension�
The more distance from the left ventricle, the lower the BP
Blood moves slowly through capillaries.
The slow process allows time for exchange of substances between blood in capillaries and surrounding tissues
Blood flow velocity increases in veins
Venous return is dependent upon three (3) factors:
1-Skeletal Muscle Pump
2-Respirator Pump
3-Valves in veins
Here is how the skeletal muscle pump works:The skeletal muscles contract-they compress the weak walls of the veins-this causes blood to move past valve-blood cannot flow backward!
Here is how the respiratory pump works: The chest expands as we inhale-this reduces pressure in thoracic cavity-blood flows from higher to lower pressure-blood cannot flow backward! The veins return blood to the heart.
5.5 Two Cardiovascular Pathways
There are two circuits in which the blood flows.
1-Pulmonary Circuit-Exchange of gases
2-Systematic Circuit-Exchanges with Tissue Fluid
Coronary Circulation
Coronary Arteries serve the heart muscle. They are the first branches off the aorta. They can become clogged due to their small diameter.
Hepatic Portal System
Hepatic Portal Vein takes blood from the capillary bed in the liver. The liver stores glucose as glycogen and synthesizes blood proteins from amino acids or stores them. The liver purifies the blood of pathogens. The hepatic vein leaves the liver and goes to the inferior vena cava.
5.6 Exchange at the Capillaries
Two forces control the movement of fluid through capillary wall-
1-Blood pressure- causes water to move from capillary to tissue fluid-
2-Osmotic pressure- causes water to move in the opposite direction-
At the Arterial end of capillary, BP is higher than the Osmotic pressure of blood-
Osmotic pressure occurs because of salts and plasma proteins-
Blood pressure is higher than Osmotic pressure at the arterial end, therefore water exit�s a capillary at this end.
Midway along capillary the two forces cancel each other out.
The venule end of capillary where the BP has fallen the Osmotic pressure is greater than blood pressure and water moves into the capillary.
Almost equal amounts of fluid leave the capillary and then return.
Some excess tissue fluid is collected by the lymphatic capillaries.
5.7 Cardiovascular Disorders
The leading cause of untimely death in the Western countries is Cardiovascular Disease.
Disorders of the blood vessels:
High Blood Pressure-Also known as Hypertension- This is when blood moves through the arteries at a higher pressure than normal. Hypertension is present when the systolic (top number) is 140 or greater and the diastolic (lower number) is 90 or greater. The diastolic number influences and is looked at more critically if medical intervention is being considered. Hypertension is common in people who have atherosclerosis (plaque build up, including fatty materials and cholesterol).Atherosclerosis is thought to be caused by smoking and diets rich in lipids and cholesterol.
Stroke, Heart Attack, and Aneurysm-
http://healthinfection.blogspot.com/2008/07/heart-and-circulatory-system-problem.html heart disease
These three heart health problems are associated with hypertension and atherosclerosis. A stroke can occur when a small cranial arteriole bursts or is blocked by an embolus. A heart attack occurs when a portion of the heart muscle dies due to lack of oxygen. When a coronary artery becomes partially blocked the individual experiences angina pectoris (pain in left arm). When a full blockage takes place then a heart attack occurs. An aneurysm is a ballooning of a blood vessel, usually the abdominal artery or arteries leading to the brain. If a major vessel bursts death is likely.
Treatments that help prevent cardiovascular disorders:
Treating clogged arteries- By pass surgery is often used. Another alternative is called the �stent�, which is a small metal mesh cylinder that holds a coronary artery open after a blockage has been cleared.
Disorders of the Heart
Heart Failure is when the heart no longer pumps as it should. This is occurring more frequently because the survival rate from heart attacks has risen, thus more people have damaged hearts so are vulnerable to heart failure.
Heart transplants are fairly common today. The number of people waiting for transplants far out number the organs available to be used.
Bioethical Focus - Paying for an Unhealthy Lifestyle:
Cardiovascular disease is the number one killer in the United States and also is one of the most expensive to treat. Cardiovascular disease is preventable. The causes of CD are mainly personal choices. Poor diet, lack of exercise, and smoking are all precursors for possible CD and 100% within a persons ability to NOT do! The person who chooses the health risk behaviors already puts themselves in a bracket that is a higher financial cost to them. The dilemma is who should pay for their health care? They already are in a higher risk/more expensive insurance cost bracket. When the insurance runs out, who then pays? Should other tax payers be made financially responsible? Should the government pay for their risky behavior choices? One argument stands on the premise that the high numbers of �CD� is exaggerated, and not really as extreme as some say it is.
http://www.nlm.nih.gov/medlineplus/ency/imagepages/19233.htm daily exercise for healthy living
Living a healthy lifestyle,regular exercise, healthy eating habits and choices, and NOT smoking are all beneficial to a persons quality and quantity of life! The one point that stands out to be true is that healthier living choices by the individuals who may currently choose unhealthy options, would benefit themselves personally and others who pay the costs for their poor choices. The costs to themselves and others can be emotional, physical, and of course financial. The costs to a persons life who suffers from Cardiovascular Disease is far more expensive than the costs and effort needed to make better life choices by choosing healthy habits.
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6.1 Blood: An Overview
http://highered.mcgraw-hill.com/sites/dl/free/0072986867/391204/chapt06_lecture.ppt#265,6,Where *-There are approximately five (5) liters of blood in the human body.
*-The heart pumps this entire amount with each beat.
*-The functions of blood are in these three categories:
1- Transport-
2-Defense-
3-Regulation-
Blood is primary transport medium in the human body. It carries oxygen from the lungs and nutrients from the digestive tract to the tissues. Blood also picks up and transports carbon dioxide and wastes from tissues to exchange surfaces in the lungs and kidneys. It is because of this process that the capillary exchanges keep the composition of tissue fluid within the normal range. Hormones are excreted into the blood and they are then transported to organs and tissues where cellular metabolism is influenced.
Blood defends the body against invasion by pathogens.
Some blood cells destroy pathogens and others secrete antibodies into the blood system.
Blood has regulatory functions. Blood assists with regulating body temperature. Salts and plasma proteins keep the liquid content high. Because of this, blood helps maintain its own water-salt balance. Blood contains chemicals known as buffers which help regulate the body ph balance.
Composition of Blood
http://www.anandhan.citycomputer.in/ red blood cells:/same picture as from L. Frolich site and from google search
Blood is a tissue.
Blood is classified as a liquid tissue.
Blood contains both cells and cell tissues, which are known as formed elements.
The cell and cell fragments are suspended in plasma.
Formed elements within blood are red blood cells, white blood cells, and platelets.
Formed Elements are made in red bone marrow.
A childs bones almost all contain red bone marrow, however, an adults bones it is much less common.
Red bone marrow contains stem cells.
There is a great scientific interest in stem cells as to what they may represent in the duplication of other types of cells that may be able to fight diseases such as diabetes and Alzheimer, plus many more.
*-Red blood cells are 2-3 times smaller than white blood cells however there are many more of them
Plasma
Plasma carries various substances in the blood and also distributes heat as a by-product of metabolism, most typically, muscle contraction. Plasma is almost 91% water. Salts, and organic molecules make up the remaining 9%.
*Plasma contains nutrients, vitamins, and hormones.
*The salts dissolve in plasma, as part of the buffers that maintain ph balance.
*Organic molecules (glucose and amino acids) are nutrients for cells.
*Urea is a nitrogenous waste product that is excreted through the kidneys.
*Plasma Proteins account for almost all the organic material found in blood.
*Plasma protein is manufactured in the liver- except for one exception.
*Plasma proteins help maintain homeostasis.
*Plasma proteins take up and release hydrogen ions.
*Osmotic pressure prevents excessive loss of plasma from capillaries into tissue fluid.
There are three major types of plasma proteins:
1-albumins-most abundant -they contribute the most to plasma�s osmotic pressure- help transport other organic molecules-
2-globulins- consist of three types, alpha, beta, gamma globulins-alpha and beta help transport other blood substances like hormones and cholesterol-gamma are produced by white blood cells NOT the liver-gamma fight disease
3-fibrinogen- active in formation of blood clots-
6.2 Red Blood Cells and Transport of Oxygen
Red blood cells (bioconcave disks) are small and lack a nucleus when mature.
They are very large in number in the human body.
How Red Blood Cells Carry Oxygen
*Red blood cells are highly specialized for oxygen transport.
*Red blood cells move singly through capillaries
*Red blood cells are bioconcave
*Instead of a nucleus, they contain many copies of hemoglobin.
*Hemoglobin is a red pigment.
*The �globulin� part of �hemo-globulin� contains four folded polypeptide chains.
*The �heme� part is an iron containing group in center of each polypeptide chain.
*The �heme� accepts O2 in lungs and lets go in the tissues.
*Red blood cells exemplify �structure suits function�- there biconcave shape gives them more surface area for gas diffusion in and out of cell.
*Internal space is used completely for oxygen transport which they do not consume any of.
How Red Blood Cells Help Transport Carbon Dioxide
Blood picks up CO2 in the tissues-
CO2 transport does not involve heme-
CO2 combines with terminal amino groups of globulin molecules.
The bulk of CO2 is transported as bicarbonate ion in the plasma-
Carbonic anhydrase is an enzyme that assists the process.
Red Blood Cells are Produced in Bone Marrow
*The RBC stem cell in bone marrow divide and produce new cells.
*As RBC mature they lose their nucleus and acquire hem globulin.
*RBC live approximately 120 days.
*RBC are destroyed in liver and spleen by white blood cells (macrophages)
*2 million RBC destroyed every second and 2 million RBC must be replace to keep the count in balance.
Blood Doping
The body boosts the number of RBCs when a lack of oxygen is delivered to the cells.
In the kidneys, a hormone is released called, Erythropoietin, which stimulates the stem cells in bone marrow to produce more RBCs.
Blood Doping is a method of increasing the normal supply of RBCs for the purpose of delivering oxygen more efficiently:
This in turn reduces fatigue, and gives a person (an athlete) a competitive edge.
Doping can be accomplished by an athlete injecting themselves, months before the competition, with EPO to increase their number of RBCS. After several weeks four units of blood are removed and centrifuged to concentrate the RBCs. The RBCS are then rein- fused before the competition. Doping is dangerous due to the blood thickening in the body and potentially causing heart attacks and or death in athletes.
Disorders Involving Red Blood Cells
Anemia is the result of insufficient number of RBCs or there is not enough hemoglobin present in the cells.
Symptoms of Anemia- tiredness and a run down feeling-
Iron, vitamins B12 ,Folic Acid enrich production of RBCs.
Hemolysis is the rupturing of RBCs-the rate of RBC destruction increase.
http://www.astrographics.com/ sickle cells microscopically
Sickle Cell Disease is inherited and is identified by sickle shaped RBCs that have a tendency to rupture as they pass through the narrow capillaries.
6.3 White Blood Cells and Defense Against Disease
http://highered.mcgraw-hill.com/sites/dl/free/0072986867/391204/chapt06_lecture.ppt#276,13,Movement of WBC�s out of circulation/ from the ARIS Powerpoint tutoria;
White blood cells have many differences from RBCs.
1- They are larger
2-they have a nucleus
3-they lack hemoglobin
4-they are translucent unless they are stained
5- they are not as numerous as RBCs
*WBCs are derived from stem cells in red bone marrow, where most types mature.
*There are several types of WBCs.
*Production is regulated by a protein called: Colony Stimulating Factor (CSF)
*WBC count can double within hours if necessary.
*WBCs can squeeze through pores in the capillary walls, because of this they are also found in tissue fluid and lymph.
*WBCs fight infection.
*Some WBCs produce �antibodies� and �antigens�.
Types of White Blood Cells
There are two types of WBCs
1-Granular Leukocytes
2-Agranular Leukocytes
�Granular Leukocytes� -includes neutrophils, eosinophils, and basophils-
�Neutrophils� are considered first responders inside the body to bacterial infections.
�Eosinophils� have a bilobed nucleus-they have large abundant granules that take up eosin and become red in color. Much is unknown as to their specific function, however, their numbers increase when a parasitic worm infection occurs.
�Basophils� have a U shaped nucleus-they become a dark blue color-they release histamine, which is associated with allergic reactions.
�Agranular Leukocytes�-includes lymphocytes and monocytes: Neither of these have granules- they both have nonlobular nuclei.
�Lymphocytes� are the second most abundant type of WBC. They are responsible for specific immunity to particular pathogens and their toxins.
There are two types of �Lymphocytes�.
1-B cells-* B cell descendants (plasma cells) protect us by producing antibodies, which are proteins that combine with target pathogens and mark them for destruction.
2-T cells-Some T cells (Cytotoxic T cells) directly destroy pathogens.
�Monocytes� these are the largest of the WBCs.
Once they become established in tissues they then differentiate into larger macrophages (but not in the skin) where they become dendrtic cells. �Macrophages� act as a vacuum cleaner and clear out old cells and cellular debris. Macrophages and dendrtic cells stimulate other WBCs to defend the body.
Disorders Involving White Blood Cells
�Severe Combined Immunodeficiency Disease� is present when the stem cells of WBCs lack an enzyme called adenosine deaminase. Without this enzyme the body is unable to fight any infections. Stem cell research is currently being used to look for a cure.�Leukemia� is cancer of the WBCs- it is uncontrolled cell growth. The bulk of the new WBCs are immature and abnormal.
�Infectious Mononucleosis� is an Epstein-Barr Virus which is a member of the herpes family. Symptoms are fever, sore throat, and swollen lymph glands. This infection lays dormant in the persons body after the symptoms disappear. Stress can reactivate the physical symptoms. Reactivation means that the virus can be passed on to someone else through their saliva.
6.4 Platelets and Blood Clotting
http://www.britannica.com/ blood -clotting as viewed under a microscope
Platelets come from fragmentation of certain large cells in the red bone marrow. Platelets are involved in the bodies process of clotting. Two plasma proteins 1-prothrombin 2-fibrinogen, which are made in the liver, are also involved in the process of clotting.
The steps of blood clotting are as follows:
1-Blood vessel is punctured
2-Platelets congregate and form a plug
3- Platelets and damaged tissue cells release prothrombin activator, which initiates a cascade of enzymatic reactions.
4- Fibrin threads form and trap red blood cells
Disorders Related to Blood Clotting
When there is an insufficient number of platelets its called, Thrombocytopenia. Symptoms include, bruising, nosebleeds, or bleeding in the mouth, and rash. It is caused by the low production of platelets in bone marrow or increased breakdown of platelets outside bone marrow.
Hemophilia is inherited and is a deficiency in the clotting process. The slightest bump can cause bleeding in the joints. The most frequent cause of death is bleeding into the brain.
6.5 Blood Typing and Transfusions
Blood transfusions are the transfer of one persons blood into the body of another person.
Blood should be �typed� prior to transfusing to prevent �Agglutination, which is the clumping of RBCs. Blood typing involves determining the ABO blood group and also to see if the blood is Rh negative or Rh positive.
ABO Blood Groups
ABO blood typing is based on the presence or absence of two kinds of antigens. Type A and type B antigen presence is dependent on the particular inheritance of the individual.
1-Type �A� blood means- RBCs have type A surface antigens. Plasma has anti-B antibodies.
2-Type �B� blood means- RBCs have type B surface antigens. Plasma has anti- A antibodies.
3-Type �AB� blood means- RBCs Have type A and type B surface antigens. Plasma has neither anti- A nor anti-B antibodies.4-Type �O� blood means- RBCs have neither type A nor type B surface antigens. Plasma has both anti-A and anti-B antibodies.
Blood Compatibility
Blood compatibility is very important during transfusions. Antibodies in plasma must NOT combine with antigens on surface of RBC or else agglutination (binding) occurs! Agglutination would be when:
Type A blood
+
Anti -A anti-bodies
=
Binding (Agglutination)
Type �O� blood is known as the �Universal Donor� because agglutination will NEVER occur with any other type of blood. Because of the possibility of other blood groups besides �ABO� the donors blood and recipients blood must be viewed on a slide microscopically. This procedure is called, �Blood-Type Matching� and it is done before a blood transfusion.
Rh Blood Groups
This is the designation of whether a person has or does not have the �Rh� factor on the RBC.
Normally humans do NOT have antibodies to the Rh factor but instead they make the antibodies when they are exposed to it.
Suppose, Mother Rh- plus Father Rh+ then;
Rh can leak across the placenta into the mother�s blood stream- This then cause the mother to produce anti-Rh antibodies-Then usually in a later pregnancy the anti-Rh antibodies may cross the placenta and destroy this child�s RBCs. This is called �Hemolytic Disease of the Newborn�. Because of RBC destruction, excess hemoglobin breakdown products in the blood can lead to brain damage, mental retardation, and even death. A shot given to Rh- women within 72 hours of giving birth can prevent Hemolytic Disease in future births of these mothers. The key factor is that the shot must be given prior to the manufacture of the Rh antibodies inside the mother.
6.6 Homeostasis
http://highered.mcgraw-hill.com/sites/dl/free/0072986867/391204/chapt06_lecture.ppt#294,36,How does the heart, blood vessels and blood work with other systems to maintain homeostasis?/from the aris Powerpoint tutorial
Homeostasis is dependent on the work of the cardiovascular system because of the interaction with the human cells.
(1) car-diovascular system must deliver oxygen from the lungs, nutrients from the digestive system to, and takes away metabolic wastes from, the tissue fluid that surrounds cells.
(2) The lymphatic system returns tissue fluids to the blood stream.
(3) The digestive system supplies nutrients
(4)The respiratory system/supplies oxygen/removes carbon dioxide
(5) The NS and endocrine systems help maintain blood pressure
(6) The lymphatic system returns tissue fluid to veins
(7) Skeletal muscles system (contractions) and the respiratory system (breathing) propel blood in the veins (movement).
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Chapter Seven: Lymphatic System and Immunity
http://www.electroresponse.com/images/immunityguy.jpg "immunity guy" Google Search
7.1 Microbes, Pathogens, and You
7.2 The Lymphatic System
7.3 Nonspecific Defenses
7.4 Specific Defense
7.5 Acquired Immunity
7.6 Hypersensitivity Reactions
7.1 Microbes, Pathogens, and You
Microbes are microscopic organisms such as bacteria.
Microbes are found everywhere in the environment.
Microbes are often beneficial to humans.
They are found in our food supply; foods such as yogurt and bread contain microbes.
Without microbes in our environment for the activity of decomposer, we and our biosphere would cease to exist.
Many human infectious diseases are caused by bacteria and viruses.
The human body has three (3) lines of defense against pathogens:
1- Barriers to entry, such as skin and mucous membranes
2- First responders, such as phagocytic WBC
3- Specific defenses kill particular disease causing agent
Bacteria
There are three common shapes:
1-Bacillus/rod shaped
2- Coccus/spherical shape
3- Spirillum/curved
www.e-picworld.com/2008/04/bacterias.html staphocopholys bacterial picture from web search
1-Bacteria cell wall contains amino-disaccharide.
2-Some cell walls are surrounded by a thick, gummy consistency “capsule”.
3-The “capsule” material helps bacteria stick to surfaces, such as, teeth.
4-“Motile Bacteria” have long, thin appendages called “Flagellum”.
5-“Flagellum” allow 360^ rotation and allow backward movement of bacteria.
6-“Fimbriae” are stiff fibers that allow bacteria to adhere to host cells, thus being able to enter the body.
7-“Pilus” is an elongated hollow appendage used to transfer DNA from one cell to another.
Bacteria are independent cells.
Bacteria DNA is packed in chromosomes in the center of the cell.Accessory rings of DNA on bacteria are called “plasmids”.
Bacteria reproduce by “binary fission”.
“Binary Fission” occurs when a circular chromosome attaches to plasma membrane and is copied.
The next step is the two chromosomes separate as the cell enlarges.
Newly formed plasma membrane and cell wall separate the cell into two cells.
Bacteria can double their numbers every twelve minutes.
Some well known bacterial diseases;
Strep Throat
Tuberculosis
Botulism
Food Poisoning
Gangrene
Gonorrhea
Syphilis
The growth of bacteria is what causes the disease.
Bacteria release molecules called “toxins” which inhibit cell metabolism.
Viruses
Viruses bridge gap between the living and the non-living.
Viruses are acellular-they are NOT composed of cells.
Viruses are obligate parasites.
Viruses do Not live independently.
Viruses cause disease.
http://science.nationalgeographic.com/science/enlarge/malaria-parasites.html Google Search
The invasion has begun. Microscopic magnification shows Plasmodium falciparum—the most virulent of the four malaria parasites that infect humans—destroying red blood cells in the liver. It digests a cell's hemoglobin, multiplies inside to the point of rupturing the cell, and rapidly spreads a new generation of infection.
Photograph by Albert Bonniers Forlag
Some well known viral diseases;
Colds
Flu
Measles
Chicken Pox
Polio
Rabies
AIDS
Genital warts
Genital Herpes
Virus particles are approximately 4x’s smaller than bacterium, which is approximately 100x’s smaller than a eucharistic cell!
Virus have two parts;
1-Outer Capsid/protein units
2- Inner core of nucleic acid
1-Virus carry the genetic information needed to reproduce itself.
2-Viral genetic material does NOT need to be double stranded DNA,nor even DNA.
3-Some viruses have RNA genome: like HIV
4-Some viruses contain enzymes that help reproduction.
5-Viruses are microscopic pirates because they take over metabolic workings of the host cell.
6-Portions of the virus adhere to a receptor in their specific host cell.
7-The viral nucleic acid enters the cell.
8-The virus may have genes for special enzymes needed for reproduction and then exit from the host cell.
9-The nucleic acid then codes for the protein units.
10-A virus relies on the hosts enzymes and ribosome for its reproduction.
Refresher from figure 7.3 pg. 123
*Virus are tiny non-cellular particles
*Bacteria are small independent cells
*Eukaryotic cells are complex and contain nucleus and organelles
Emerging Viruses
Viruses can emerge by transporting from one location to another where it has never been before.
Many viral disease are transported by (vectors) insects.
In molecular biology, a vector is any vehicle used to transfer foreign genetic material into another cell)Diseases spread by insects may be extremely difficult to control.
A disease can emerge when a mutation allows a virus to use new/different insect.
Viruses can emerge due to the immune systems inability to recognize change in the virus.
Viruses that are continually changes/mutating are difficult to control.
Prions
Prions are “Proteinaceous infectious particles that cause group of degenerative diseases of the nervous system.
These diseases used to be considered viral but they are not.
Prions are proteins of unknown function in the brains of healthy individuals.
Prions cause:
Prions are the cause of, Creutzfeldt-Jakob disease in humans and scrapie in sheep and Mad Cow Disease in bovine.
It is believed these diseases are caused by the ingestion of brain and nerve tissue from animals that are infected.
Prions are proteins of unknown function in the brains of healthy humans.
Disease occurs when prion protein turn “rogue” (altered shape). Malfunction occurs because of the “wrong shape”.
Prion disease in humans is low.
Science Focus: Avian Flu, A Disease of Birds
The occurrence of disease, such as the Avian Flu, jumping from one species to another is of great concern to the scientific community. Since 1997 there has developed a deadly strain of this flu type which has been showing up in a number of different countries.
The biggest concern is the potential of the “Bird Flu” strain merging with a “Human Flu’ strain and becoming a “Hybrid” strain of large proportion. A hybrid strain could then be passed quickly and easily from person to person because of high population and also because of easy access to world travel. A “Pandemic” (worldwide disease) is then possible if this was to happen.
Since 2005 there has been only one known case of the “human to human” transmission of the Avian flu. Each time this virus jumps from bird to human the risk increases for a hybrid strain to mutate.
Asian countries at this time are trying to contain and end the spread of the virus by destroying the bird populations that have been infected. At this time the infected fowl have been destroyed and helped the spread of the deadly virus to domestic livestock. At this time attention is being focused on prevention of waterfowl contamination, thus eliminating some of the danger of the flu virus crossing to Central and South America, and also the United States.
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The link below is for a magazine story I found in “The National Geographic,” that is written about the topic of viruses and disease infiltrating human beings. It is a great article about Horizontal Gene Transfer (HGT) and viruses.
“Evolution Getting Faster Thanks to Germs, Viruses, Study Says”
Written by Brian Handwerk
March 5, 2007
http://news.nationalgeographic.com/news/2007/03/070305-evolution-germs.html (article link)
7.2The Lymphatic System
The lymphatic system consists of two parts.
1- lymphatic vessels
2- lymphatic organs
The Lymphatic System is closely associated to the Cardiovascular System.
The Lymphatic System has four functions that support homeostasis.
1-Lymphatic capillaries absorb excess tissue fluid and return it to the blood stream.
2- Lymphatic capillaries in small intestines absorb fats (lipoproteins0 and transport to the blood stream.
3-Production, maintenance, and distribution of lymphocytes is controlled by the Lymphatic System.
4- The Lymphatic System helps protect the body from pathogens.
Lymphatic Vessels
These vessels form a one way system of capillaries, vessels, and ducts that take lymph to cardiovascular veins in the shoulders.
The fluid inside lymphatic vessels is called lymph.
Lymph is a colorless liquid but after food is ingested it turns creamy because of lipid content.
The lymphatic system has two ducts.
1- Thoracic Duct
2- Right Lymphatic Duct
Movement of of lymph within lymphatic capillaries is influenced by the skeletal muscle contractions.
Lymphatic Organs
Lymphatic organs have “primary”, which are red bone marrow and thymus gland and also “secondary”, which consist of lymph nodes and spleen.
The Primary Lymphatic Organs
Bone marrow produces RBC’s, various types of WBC’s, neutrophils, eosinophils, basophils, lymphocytes, and monocytes.
B cells mature in the bone marrow.
T cells mature in the thymus.
The thymus gland has two functions:
1- Production of thymic hormones (thymosin) which aids in the maturation of T lymphocytes. Thymosin may aid the immune system in other ways as well.
2- Migration of T lymphocytes from bone marrow through blood stream to thymus where they then mature. If they are reactive they die. If they have potential to fight off pathogens then they leave the thymus.
The thymus is critical to the bodies immune system because without mature T cells, the bodies defensive response to pathogens is poor or completely absent.
Secondary Lymphatic Organs
The spleen is the largest lymphatic organ in the human body. The spleen filters blood.
Lymph Nodes occur along lymphatic vessels and filter lymph.
Lymphatic Nodules are concentrations of lymphatic tissue not surrounded by a capsule. Tonsils are patches of lymphatic tissue located in a ring about the pharynx. Tonsils fill the same function as lymph nodes.
7.3 Nonspecific Defenses
Immunity is the bodies ability to fight off diseases and cancers.
Both of the following are considered “non-specific” because they act indiscriminately against ALL pathogens.
1- Barriers to entry bar the entry of pathogens into the body.
2- Inflammatory Response is a special reaction the body has when it is first invaded by a pathogen. Protective proteins are also involved.
Barriers To Entry
Barriers to entry can be both physical and chemical that are the first line of defense against infection by pathogen.
Skin and Mucous Membrane- effective barrier that prevents infection, also provide a physical barrier to entry. Ciliated cells that line upper respiratory tract sweep mucus up to the throat where it can be swallowed or spit out.
Chemical Barrier- secretions of oil gland of the skin- contain chemicals that weaken or kill certain bacteria on the skin. Perspiration, saliva, and tears contain lysozyme. The acid pH balance inside the stomach inhibits/stops growth of many bacteria.
Resident Bacteria- normal flora, including microbes that are present inside the human mouth, intestines, and other areas provide a significant chemical barrier against pathogens.
Inflammatory Response
The second line of defense in the body
The inflammatory response (such as swollen ankle example) involves 4 signs of distress:
(1) redness
(2) heat
(3) swelling
(4) pain
These occur becuae of changes in the capillaries of damaged area of body.
Neutrophils, cytokines, and macrophages all assist in the inflammatory response defense of the body.
Protective Proteins
Interferons are proteins designed to act as warnings to non-infected cells. These “interferons” are produced in virus infected cells.
7.4 Specific Defense
Antigens are molecules the immune system recognizes as foreign.
Specific defenses respond to antigens.
Specific Defenses depend on B cells or T cells.
Specific antigen receptors refers to plasma membrane receptor proteins- specialized shape allows them to combine with particular antigens.
Lymphocyte has one type of receptor.
Receptor and antigen fit perfectly together.
We have a diversity of T and B cells because of all of the millions of antigens we will encounter throughout our life time.
During normal maturation process there are T and B cells designed for any possible antigen.
B Cells and Antibody- Mediated Immunity
*B cells become plasma cells and memory B cells. Most cloned B cells become plasma cells.
*Apoptosis is the process of programmed cell death. (Specific and predictable events that lead up to the end of living cells in the human body).
Defense by B cells is known as anti-body mediated immunity.
T Cells and Cell- Mediated Immunity
*A T cell has unique T cell receptor (TCR) when it leaves the thymus.
*T cells can NOT recognize an antigen without help.
*The antigen must be displayed and have antigen-presenting cell.
The characteristics of T cells are:
*Cells mediated immunity against virus-infected cells and cancer cells
*Produced in bone marrow- mature in thymus
*Antigen must be presented in groove of an HLA molecule
*Cytotoxic T cells destroy nonself antigen- bearing cells
*Helper T cells secrete cytokines that control the immune response
7.5 Acquired Immunity
Active Immunity
Immunity can be brought about either naturally or artificially.
Active immunity occurs after a person has been infected with a pathogen.
Active immunity can be induced through vaccines.
Immunization is exposure to specific pathogens that have been treated so they can no longer cause disease when given through vaccination.
Passive Immunity
Passive immunity occurs when a person is given prepared antibodies or immune cells to combat a disease.
Passive immunity is only temporary because the antibodies are not produced by the individuals own plasma cells.
Gamma Globulin injection is serum that contains antibodies.
Monoclonal antibodies are produced by the same plasma cell. They are beneficial in the detection of infections and treating cancers.
Cytokines are a form of passive immunity that is used in the treatment of AIDS. It is also used to promote the body’s ability to recover from cancer.
7.6 Hypersensitivity Reactions
When the immune system responds in a way that is harmful to the body then this is known as hypersensitivity reaction.
Allergies are hypersensitivities to substances like pollen or certain foods.
These antigens are called allergens.
An immediate allergic response can happen within seconds of exposure.
Anaphylactic Shock is an immediate allergic response due to the allergen entering the person’s blood stream.
A delayed allergic response is initiated by Memory T Cells at the site of allergen contact.
Tissue rejection occurs after a transplant because the person’s immune system recognizes that the transplanted tissue is foreign. The catatonic T cells respond by attacking the cells of the transplanted tissue.
Immunosuppressive drugs can assist the body in accepting transplanted organs. The transplant must be carefully selected and matched to the recipients body.
Disorders of the Immune System
Myasthenia Gravis- antibodies attach to and interfere with function of neuromuscular
Multiple Sclerosis- T cells attack the myelin sheath of nerve fibers
Systemic Lupus- deposition of excessive antigen-antibody complexes
Rheumatoid Arthritis joints are negatively affected
A compromised immune system prevents protection from antigens. The immune deficiency leaves the human body prey to outside pathogens or antigens.
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WEB LINK COMPENDIUM NOTES
Web Link-The Immune System’s Response to Invading Microbes
The immune system responds to these pathogens in an attempt to rid the body of the invading harm
A pathogen enters the body through bacteria or virus.
The body recognizes the pathogen, and the macrophases ingest, process, or display the pathogen on sueface of their cells.
Antigen Presenting Macrophase interacts with T-cells and together they recognize the same antigens.
An alarm is set off by the macrophase during this interconnected process with the Macrophase and the T-cell.
The “Alarm” is called the Interleukin I which stimulates T-helper cell to secrete
Interleukin II.
Interleukin II cells start chain re-action of Cytotoxic T cell and the B cell proliferation.
The next reaction goes either of two ways:
Cytotoxic T cells- recognize toxins on the infected cells of the body, bind to those cells, and produce specific chemicals that kill off the infected cells to rid the body of the pathogen.
B cells recognize pathogens on the infected cells.
The B cells become activated by T-helper cells and are able to differentiate into plasma cells.
The created plasma cells then become “Antibody Producers” to then be sent out and attach to the antigens who then signal the macrophases to attack and then kill off the harmful microbes in the body.
Some of the B cells turn into “Memory Cells” that can last in the body for decades.
It is because of these memory cells that a re-exposure to specific diseases is readily acknowledged and then dealt with by the immune system.
The body has created an immunity against the disease which means the body does not be- come as ill or ill at all from exposure to the disease.
Web Link- Hemoglobin Causes Net Diffusion of Oxygen
Oxygen diffuses into the blood stream.
Oxygen then transports to cells and diffuses into them.
Carbon Dioxide carries out the same process but in reverse.
The diffusion rate is key to how efficient the gas exchange is.
OXYGEN ß -------à Carbon Dioxide
The concentration gradiant determines the rate of diffusion.
The greater difference in gas concentration across a membrane, the more quickly the gas will diffuse.
The diffusion process reduces the gradiant.
With the gases being removed from the blood, hemoglobin can maintain concentration gradients and continuous diffusion of oxygen and carbon dioxide.
Web Link- Sickle Cell Anemia
Symptoms/complaints
“Muscular Rheumatism
Malaise
Pain in Back
Vomiting
Dark urine
Bad Cough
Death
Unusual RBC formation was discovered as the main abnormality of the disease.
Sickle Cell Anemia is a disease that affects RBC and hemoglobin that they contain.
It generally runs in families. Hemo S + Hemo C = Abnormal cell
It is a genetic mutation that is inherited by the principle of incomplete dominance.
Mutation affects the hemoglobin molecule. The Sickle Cell is a defective structure in a protein molecule. Sickle Cell Hemoglobin differ from normal hemoglobin by a single amino acid. It results from a specific amino acid substitution in a protein polypeptide.
AIDS/HIV and The Immune System
Human Immunodeficiency Virus -HIV is what it is called when this virus has entered a person's body. AIDS is "Active Symptoms" within the person-it is when signs of the disease are present. The HIV virus attacks and destroys Helper T cells when someone is infected. The immune system is compromised because when there are not enough Helper T cells, then the B cells do not get the signal they need to produce antibodies or Cytotoxic T cells to fight off and destroy the HIV infected cells. Once homeostasis is compromised to the point of serious illness, helper T cells are so low in number they can no longer perform the necessary response needed to fight off infections and other illnesses.
HIV's ability to bind onto the cell can be inhibited with fusion/entry inhibitor drugs. The HIV virus can integrate into DNA and become a part of the cellular genome,. If this takes place in the infected person, it is irreversible.
The virus uses cellular machinery to synthesize viral proteins. Several of these are long amino acid chains which must be cleaved by a specific viral protease before new viral particles can become active. Protease inhibitors block viral maturation at this step.
The virus frequently adapts and changes into a resistent strain which does not respond to current drug treatments. Treatment is very expensive and many countries are not able to agressively treat the virus.
Education and awareness of unsafe behaviors has been and still is the number one weopon of defense against the HIV virus.
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