UNIT 4 - RESISTANCE & IMMUNITY Flashcards
Granulocytes (3)
- Neutrophils
- Eosinophils
- Basophils
Agranulocytes (2)
- Lymphocytes
- Monocytes
Importance of leucocyte count
Each leucocyte has a definite purpose and seeing changes in specific types can help diagnose a problem
Differential count
Used in diagnosis of an infection/disease on basis of an increase or decrease in numbers of specific types of WBC
Relative quantities of leucocytes in blood (5)
- Neutrophils (60-70%) - Lymphocytes (20-25%)
- Monocytes (3-8%)
- Eosinophils (2-4%)
- Basophils (0.5-1%)
Lymphatic system
Group of organs, vessels, and tissues that protect us from infection and keeps a healthy balance of fluids throughout the body
Plasma
Fluid portion of blood
Interstitial fluid
Fluid between tissues and cells (bathes tissues)
Lymph
Fluid in lymphatic vessels (mostly interstitial fluid) that bring back fluid from body and drain into circulatory system through two ducts in neck region
Lymph nodes
Located in lymphatic vessels that contain WBC to filter and cleanse the lymph of pathogens and abnormal cells before returning to circulatory system
Movement of lymphatic system (4)
- Interstitial fluid with the white blood cells enters lymphatic capillaries through small pores
- Fluid inside lymphatic capillaries (lymph) flows through lymphatic vessels throughout body
- Microbes and foreign particles present in circulating lymph encounter macrophages, dendritic cells, and lymphocytes that carry out various defensive actions within lymph nodes
- Lymphatic vessels return lymph to the blood via 2 large ducts that drain into vein near neck/shoulders
What happens to the majority of fluid that leaves the capillaries
The majority of fluid that leaves the capillaries is returned to the circulatory system, but approximately 15% remain in tissues as part of interstitial fluid and blood volume in arteries is 15% more than veins
What happens to this “lost fluid” and how is arterial volume restored
Restored to the circulatory system through lymphatic system
Functions of lymphatic system (4)
- Drains excess interstitial fluid to restore blood volume
- Protects against invasion through immune responses
- Transports dietary lipids and some vitamins from the gastrointestinal tract to the blood
- Return tissue fluid back to circulatory system
Drains excess interstitial fluid to restore blood volume
One way transport system that drains fluid from all body tissues and returns it to the blood at the left and right subclavian veins
Protects against invasion through immune responses
Lymph pass through nodes that contain WBC and initiate defensive and immune responses
Lymph
Fluid in lymph vessels, mostly just interstitial fluid in lymphatic vessels that bring back fluid from body and drain into circulatory system through two ducts in neck region
Nodes
Oval/bean shaped swellings situated throughout lymphatic vessels to filter fluid within vessels
2 ducts in neck region:
- Right lymphatic duct –> right subclavian vein
- Thoracic duct –> left subclavian vein
Structural characteristic of the circulatory system
Moves as a circuit with a pump
Structural characteristics of the lymphatic system
One way system and has no pump. The movement of lymph is due to pressure differences aided by muscular action (smooth/skeletal) and forced through vessels
Spleen
Contains the largest amount of lymphoid tissue in body and controls the level of white blood cells, red blood cells and platelets
Tonsils
Masses of lymphoid nodules in pharynx and functions in filtering and immunological role
Thymus
Small grainy lymphoid organ located behind sternum for maturating of certain WBC
Resistance & immunity
Refers to the body’s ability to protect itself from foreign substances and pathogens (avoid disease)
2 major lines of defense of the immune system
- Innate (inherited) non specific resistance
- Adaptive specific resistance
Innate (inherited) non specific resistance
First line of defense that provides protective mechanisms to all people and responds in the same way to all potential invaders
Types of innate (inherited) non specific resistance:
- External defenses: skin & mucous membranes, body secretions
- Internal defenses: antimicrobial proteins, phagocytosis, fever, inflammation
Skin and mucous membrane
Unbroken skin and mucous membranes act as mechanical barrier to bacteria and viruses
Mucous
Produced in respiratory tract to trap debris and germs swept out by cilia
Gastric juice
Acid and enzymes in the gut to kill off bacteria and virus
Tears
Flush the eyes to remove dirt and bacteria containing enzyme lysozyme
Saliva
Flushes inside of the mouth containing enzyme lysozyme and immunoglobin
Sweat and oil
Produced by the skin, where sweat flushes skin and deposits salt on skin surface and oil from sebaceous glands contain antimicrobial compounds
Antimicrobial proteins
Proteins present in plasma or produced by infected cells
2 principle components of antimicrobial proteins
- Interferon
- Complement
- They are both also part of adaptive specific resistance
Interferon
Protein produced by infected cells that bind to surrounding non-infected cells and cause them to produce substances that interfere with viral replication
Complement
Protein produced by the liver found in plasma that bind to bacterial cells to attract phagocytes and cause holes in bacteria walls and consequent rupturing
Phagocytosis
Involves various white blood cells (macrophages, neutrophils, dendritic cells) that engulf foreign materials upon contact aided by complement proteins and fevers (phagocytes function better at high temperatures)
Fever
An abnormally high body temperature commonly occurring during infections
Impact of a high temperature (4)
- Intensifies effect of interferon
- Increases phagocytic action
- Inhibits growth and multiplication of microbes
- Speeds up bodies repair and resistance mechanisms
Inflammation
Response by the body to tissue damage due to injury and/or infection to prevent spread of infection and prepare the area for repair and destroy toxins
Symptoms of inflammation (3)
- Localized pain
- Swelling (caused by WBC releasing histamine, prostaglandin, complement, etc)
- Redness/heat (caused by vasodilation and blood vessels more permeable so WBC move out quickly)
Process of inflammation (3)
- Blood vessels dilate bringing increased blood flow to injury
- Phagocytes migrate to the injury site and ingest microbes and other foreign substances
- Lymphatic drainage removes dissolved poisonous substances for healing
Antigen
Something that is able to trigger an immune response if body is foreign to it (Create a defence)
Antibodies
Protein produced by immune system to fight against specific invaders (antigens) like bacteria or viruses
2 characteristics of antigens:
- Immunogenicity
- Reactivity
Immunogenicity
Ability to provoke immune response