Chapter 8.3 Flashcards
What is the other transport system in the body known as?
The lymphatic system
What is the lymphatic circulatory system?
A network of vessels with associated glands or nodes that extend throughout the body
What do the lymphatic vessels collect?
A fluid called lymph which is made of interstitial fluid
What color is lymph?
Colorless or pale yellow. It is much like the plasma in blood
What does the lymphatic system do?
Helps to maintain the balance of fluid in the body
How does plasma enter the interstitial fluid?
As blood circulates through the body, some plasma escapes from the capillaries and becomes part of the interstitial fluid that bathes the cells of the body
What does plasma that leaks from the capillaries go?
From the interstitial fluid it is absorbed into the lymphatic system. Eventually it re-enters the circulatory system through ducts that empty into large veins near the heart
What do lymph formations look like?
Since they are not a continuous cycle, they form close ended tubes around capillaries that are to be delivered to the heart
Where are specialized lymph capillaries found?
In the intestinal villi. They help to carry digested fats throughout the body
How does the lymphatic system work with white blood cells?
They allow lymphocytes (white blood cells) to mature in lymph nodes
What do lymph nodes contain?
Aside from allowing white blood cells to mature in them, they contain macrophages
What do macrophages do?
They trap and destroy bacteria that are circulating within the body
What does an infection cause your immune system to do?
Increase the number of macrophages and lymphocytes in your lymph nodes
How does the human body defend itself against pathogens?
By either preventing them from entering or destroying them if they do enter
What are the 3 groups of the bodies defence of pathogens?
- Barriers to keep pathogens out
- General or non-specific defences against a wide variety of pathogens
- Specific defenses against particular pathogens
What are the common physical and chemical barriers against pathogens?
Eyelashes
Cilia
Tears
Stomach Acid
What is the largest barrier against pathogens?
The skin
Why is the skin a hostile environment for micro-organisms?
Because it is dry and contains large amounts of tough indigestible keratin
What does the skin’s oil contain?
Bactericides. Perspiration also forms an acidic layer that is inhospitable for microbial growth
What is the second line of defence in the body?
Non-specific defenses
What is the non-specific defenses made up of?
3 types of white blood cells called macrophages, neutrophils and monocytes
What is cell mediated immunity?
A non-specific defense where 3 types of white blood cells are released
What do neutrophils, monocytes, and macrophages do?
They are white blood cells that kill bacteria using phagocytosis
How are macrophages made?
They develop from monocytes
Where are macrophages found?
Liver, Spleen, Brain, Lungs, and circulate in the blood and interstitial fluid
What does non-specific defense also include?
Natural killer cells which target body cells that have become cancerous or infected by viruses
What is the 3rd line of defense called?
Immunity
What is immunity developed by?
The actions of specific defenses that use antibodies
What is antibody-mediated defenses?
A specific defence using antibodies
What are antibodies?
Proteins that recognize foreign substances and act to neutralize or destroy them
Why does each person develop an immune system?
Because of exposure to foreign substances and variation in genetic makeup
Why do some diseases require a stronger response than others?
Because they are more virulent than others
What is the specific immune system primarily a function of?
Lymphocytes in the circulatory system
What are the 2 specific groups that lymphocytes are divided into?
Depending on where they mature they may be B lymphocytes (B cells) or T lymphocytes (T cells)
Where do B cells mature?
In the bone marrow
Where do T cells mature?
The thymus gland which is located near the heart
Why does the body catalogue molecules in the body?
So that the body can recognize proteins and other molecules as part of itself and not attack itself
What are antigens?
Molecules that are found on the surface of the cells and pathogens
What do antigens do?
Provide an identification system
What do antigen receptors on T and B cells do?
Allow them to recognize foreign antigens and begin responding to invasion
Why do antibodies have the same shape of an antigen receptor?
So they can bind with and neutralize antigens
Why does an injury become warm and swollen?
The second line of defense, non-phagocytic leukocytes release histamine which causes blood vessels to dilate
What does puss come from at the site of an infection?
When phagocytic macrophages engulf and destroy bacteria, dead macrophages and bacteria look like pus
When does the 3rd line of defense occur?
After the pathogen has been destroyed. When the antigens from the pathogens protrude from the macrophage
What happens after macrophages have killed bacteria?
The 3rd line of defense begins when the T cell bind to the antigens on the surface of the macrophage.
What happens when the T cells bind with the antigen?
This triggers the release of T cells to multiply and destroy infected tissue
What do the B cells do?
The antibodies of B cells bind to antigens killing pathogens
What happens when T cells and B cells unite?
This union activates B cells causing it to enlarge and divide which produces plasma and memory cells
What does the plasma do in the 3rd line of defense?
They produce antibodies that are were created by the B cell at a rate of 2000 per a second and release them into the blood stream.
Where do antibodies and memory B cells go?
They remain in the blood ready to fight a new infection by the same pathogen
Why do different B cells produce different antibodies?
To increase variation and the possibility that the body will have an antibody that can recognize and bind to an invading pathogen
What happens when a pathogen is destroyed by phagocytosis?
Antigens from pathogen move to the surface of the macrophage that destroyed it.
What happens when the antigens are present on the surface of the macrogens that destroyed a pathogen?
A T cell called a helper T cell recognizes the antigen and gives off chemical signals
What do the chemical signals that the helper T cell give of do?
Stimulates the action of macrophages, B cells and other T cells
What is another name for killer T cells?
Cytotoxic T cells
What do killer T cells do?
Bind with infected cells and destroy them by puncturing a hole in their cell membranes
How are killer T cells activated?
Indirectly by chemical signals from helper T cells or directly by the presence of an invading pathogen and the associated antigen
What do suppressor T cells do?
Slow and suppress the process of cellular immunity to ensure that normal tissue does not get destroyed
What do memory T cells do?
Remain in the blood stream and are able to act quickly if the antigen is encountered again
What is a blood transfusion?
A transfer of blood from in person into the blood of another
Why are only certain types of blood compatible?
Because red blood cell membranes carry specific antigens to blood recipients
What are the most common antigens found on red blood cells?
ABO
How does the ABO system determine blood type?
By the presence or absence of type A and type B antigens on red blood cells
What are the presence or absence of antigens influenced by?
Antigens are an inherited characteristic
What type of a blood does a person with a type A antigen have?
Type A Blood
What type of blood does a person with type B antigens?
Type B blood
What type of antigens does a person with AB blood have?
Both A and B antigens
What type of antigens does a person with type O blood have?
They have no antigens
What type of antibodies does a person with type A blood have?
Anti-B antibodies in the plasma
What type of antibodies does a person with type B blood have?
Anti-A antibodies in the plasma
What type of antibodies does a person with type O blood have?
Both anti-A bodies and anti-B bodies
When do antibodies in the blood appear?
They appear within several months after birth
What can the presence of the antibodies cause?
Agglutination
What is agglutination?
The clumping of red blood cells when that occurs when incompatible blood types mix
What can happen as a result of agglutinated red blood cells?
They can clog vessels blocking circulation causing severe damage to organs
What type of antibody does type AB blood have?
They have no antibody
What is an antigen?
A molecule found on the surface of cells and pathogens that can be recognized by the body’s immune system
What is an antibody?
Proteins that recognize foreign substances in the body and neutralize or destroy them
What is another group of antigens found on red blood cells called?
The Rh factor
What are people with Rh factor termed?
Rh positive (Rh+)
What are people without the Rh factor in the red blood cells called?
Rh negative (Rh-)
What do people without the Rh factor usually not have?
Antibodies to the Rh factor?
When can people make antibodies to the Rh factor?
When they are exposed to the Rh factor during pregnancy or a blood transfusion
How does a mother make the Rh factor antibody?
The baby can be Rh positive, the Rh+ blood cells can leak across the placenta into the mother’s bloodstream. This causes the mother to immune system to produce anti-Rh antibodies
What can happen to a baby after a subsequent regarding Rh-antibodies?
The anti-Rh antibodies can leak may leak across the placenta and destroy a child’s red blood cells
What is hemolytic disease of a newborn (HDN)?
When a mother has anti-Rh antibodies and this leaks across the placenta and destroy a child’s red blood cells
What can HDN lead to?
Brain damage, deafness, and death
What happens as red blood cells break down in HDN?
The liver produces a substance called bilirubin in excess, that bilirubin up in the baby’s blood and tissues
What is bilirubin?
A pigment produced by the liver that causes a baby’s blood tissues to turn yellow. Or become jaundiced
What is the treatment for HDN?
Blood transfusions for the child or inducing early labor to prevent the situation from becoming worse
How is the Rh problem prevented?
By injecting Rh- women with an antibody preparation against the Rh factor within 72 hours after the birth of an Rh + child
