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NATS 1670 Chapter Notes -Anatta, Natural Killer Cell, Lactobacillus

Natural Science
Course Code
NATS 1670

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January 3 2012 - Immunity and Disease pp. 271 to 295
Three lines of defense protect the body
1. The body’s array of physical and chemical barriers to infection
Examples include intact skin and the linings of body cavities and tubes
IMMUNE SYSTEM: a system of interacting white blood cells that defend the body
o Known as a “cellular system” because the white blood cells perform most of the functions
ANTIGEN: a molecule or particle that the immune system recognizes as non-self
Triggers an immune response
o Most are proteins, lipids or the large sugar molecules called oligosaccharides
o All virus particles, foreign cells, toxins and cancer cells have antigens on their surface
IMMUNITY: the body’s overall ability to resist and fight infections
We are born with some general immune defenses and acquire other, specific ones
2. We are born with some pre-set responses to infection that are carried out by certain white blood
cells and proteins in the blood
o Triggered by chemical cues that are present on or in a variety of pathogens
INNATE IMMUNITY: the body’s inborn, general defense against infection
o Innate immune responses are general
3. ADAPTIVE IMMUNITY: a set of immune defenses that are tailored to the particular pathogens that
enter the body
o Triggered by innate immune responses
o Changes as we go through life
o Huge numbers of white blood cells mount a counterattack against the invasion
o Adaptive responses can be mounted against a vast array of potential pathogens (they take
about a week to develop but they leave behind cells that “remember” an antigen and protect
against it for a long time
Comparison of Innate and Adaptive Immunity
Innate Immunity
Adaptive Immunity
Response Time
7 to 10 days
How Antigen is Detected
About 1000 pre-set
Vast number of receptors
for specific antigens
Non-self chemical cues on
or in pathogens
Antigens of pathogens,
toxins, proteins on altered
body cells
White blood cells and their chemicals are the defenders in immune responses
- White blood cells operate in both the innate and adaptive immune responses (all release
substances that help muster or strengthen defense responses)
CYTOKINES: signalling chemicals released by cells of the immune system, they promote and regulate
many aspects of immunity

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Circulate in the blood:
NEUTROPHIL: phagocyte that follows chemical trails to infected, inflamed, or damaged tissues
o Make up 2/3 of white blood cells that circulate in blood
EOSINOPHILS: white blood cells that targets large parasites, such as worms
o Also play a part in allergies
BASOPHILS: circulating white blood cell, and release substances from their granules that cause
Perform their functions while in tissues:
MAST CELLS: white blood cell in many tissues, and have granules that release substances causing
MACROPHAGES: phagocytic white blood cell in tissue fluid
DENDRITIC CELLS: phagocytic white blood cell
o Alert the adaptive immune system when they detect antigens
LYMPHOCYTES: B cells, T cells, and other white blood cells that are active mainly in tissues and organs of
the lymphatic system
B CELLS: B lymphocyte. Cells derived from them make antibodies
T CELLS: T lymphocyte. T cells target abnormal body cells, among other roles in adaptive immunity
The lymphatic system
LYMPHATIC SYSTEM: organs and tissues that return tissue fluid to the cardiovascular system and have
roles in defenses
LYMPH: the tissue fluid that moves in lymph vessels
- Tonsils defense against bacteria and other foreign agents
- Right lymphatic duct drains right upper portion of the body
- Thymus gland site where certain T lymphocytes acquire means to chemically recognize specific
foreign invaders
- Thoracic duct drains most of the body
- Spleen major site of antibody production; disposal site for old red blood cells and foreign debris;
site of red blood cell formation in an embryo
- Some lymph vessels return excess tissue fluid and reclaimable solutes to the blood
- Bone marrow red marrow in some bone is where whit blood cells are produced
The lymph vascular system functions in drainage, delivery, and disposal
LYMPH VASCULAR SYSTEM: lymph capillaries and other vessels of the lymphatic system
o They collect water and dissolved substances from tissue fluid and transport them to ducts
of the cardiovascular system
o The system starts at capillary beds where fluid enters the lymph capillaries through valves
that are areas where endothelial cells overlap. The capillaries then merge into lymph
vessels that have smooth muscle and valves that prevent backflow. Then they converge
into collecting ducts that drain into veins in the neck.
o Movement of skeletal muscles and the rib cage help move the fluid
Lymphoid organs and lymphatic tissues are specialized for body defense
LYMPH NODES: organs of the lymphatic system that filter lymph; they are located an intervals along
lymph vessels
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