Redo 8.3 Flashcards
What is the lymphatic circulatory system?
A network of vessels, with associated glands or nodes that extends throughout the body
What does the lymphatic system collect?
A fluid called lymph
What is lymph made of?
Interstitial fluid
What is interstitial fluid?
Fluid that surrounds all cells in the body
What color is lymph?
Colorless or pale yellow
What does the lymphatic system do?
Helps to maintain the balance of fluids in the body
How does plasma enter the lymph vessels?
As blood circulates the capillaries, some plasma escapes and become part of interstitial fluid. It is then absorbed into lymph vessels
How does plasma rejoin the main circulatory system?
Through ducts that empty into large veins near the heart
Why isn’t the lymphatic system a continuous circuit?
Because lymph forms in close ended tubes in capillary beds
What do specialized lymph vessels do in the intestines?
Some lymph capillaries are found in intestinal villi, they carry digested fats throughout the body
What does the lymphatic system work with white blood cells to do?
Protect the body against infection
Where do lymphocytes mature?
In the lymph nodes
What are lymph nodes?
Glands that are found throughout the lymphatic system
What are lymphocytes?
A type of white blood cell
Where are macrophages found?
In the lymph nodes
What do macrophages do?
Trap and destroy bacteria
What can an infection do to the lymphatic system?
Cause the number of macrophages and lymphocytes to increase
What is a pathogen?
A biological agent that causes disease or illness to its host
How does the human body defend itself against pathogens?
By preventing entry or destroying them when they enter
What are the 3 defences of the body?
- Barriers to keep pathogens out
- General/non-specific against a wide variety of pathogens
- Specific defenses against particular pathogens
What is the first line of defence?
The physical and chemical barriers of the body
What are examples of the physical and chemical barriers of the body?
Eyelashes Cilia of the respiratory tract Tears Stomach Acid The skin
What is the largest first defence against pathogens?
The skin
Why is the skin a hostile environment for microorganisms?
The outer layer is dry and contains large amounts of keratin which is tough and indigestible
What does the skin’s oil contain?
Bactericides
What does perspiration do to the skin?
Forms an inhospitable layer for microbial growth
What is the second line of defense for the body?
Non-specific defenses
What types of white blood cells does the non-specific defenses contain?
Macrophages
Neutrophils
Monocytes
What is cell mediated immunity?
A non-specific defense that involves activation of macrophages, neutrophils, and monocytes
What do neutrophils, monocytes and macrophages do?
They are white blood cells that kill bacteria using phagocytosis
Where do macrophages develop from?
Monocytes
Where are macrophages found?
Liver Spleen Brain Lungs Blood and interstitial fluid
Which defense are natural killer cells found in?
Non-specific defense
What do natural killer cells do?
Target body cells that have become cancerous or infected by viruses
What are the names for the 3rd line of defense?
Specific Defenses or Immunity
What is immunity developed by?
The actions of the specific defenses using antibodies
What is antibody-mediated immunity?
A component of the immune system that involves the activation of lymphocytes and the secretion of antibodies specific to a specific antigen
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 substance overtime and variations in genetic makeup
What is an immune system?
The unique ability to deal with a wide variety of possible infections
What is the function of the specific immune system primarily a function of?
Lymphocytes in the circulatory system
What are the 2 groups that lymphocytes divided in the specific immune system?
B lymphocytes (B cells) or T lymphocytes (T cells)