Lymphatic and Immune systems Flashcards
Four main functions of the lymphatic system
- lymphatic capillaries absorb excess interstitial fluid and return it to the bloodstream
- Lymphatic capillaries called lacteals in the small intestine absorb dietary fats and transport them to the bloodstream
- Production, maintenance and distribution of lymphocytes in the body
- Helps in defense against pathogens
Lymph is a milky fluid containing
- White blood cells
- Proteins
- Fats
- Occasionally bacteria and viruses
Lymph nodes remove____
microorganisms, debris and abnormal cells from lymph and cleanse the lymph
Nodes are composed of
connective tissue, macrophages and lymphocytes
what transport lymphs
lymphatic vessels
Nodes acts as
filters, cleansing the lymph as it passes through them
where is the spleen located
located in upper left abdominal cavity
two regions of spleen
red pulp
white pulp
red pulp
removes old and damaged red blood cells
temporary blood storage
White pulp
contains lymphocytes, searching pathogens
Disease that cause spleen enlargement
Infectious mononucleosis, leukemia
Thymus
Located behind the sternum, above heart
Site of maturation of T cells (T lymphocytes)
Largest and most active during childhood
Lymphatic organs
- tonsils
- adenoids
- peyer patches
Tonsils
Filter food and air entering the throat
Adenoids
Located at the back of the nasal passages and filters air entering the respiratory tract
Peyer patches
Found in the intestinal walls and the appendix
Fight infections that come in via the digestive tract
Immunity
killing or removing foreign substances, pathogens and cancer cells from our body
Two branches of our immune system:
innate and adaptive
innate
Fully functional without previous exposure to a pathogen
Adaptive
is initiated when exposed to a pathogen
Innate (nonspecific defenses) immune defenses include
- physical and chemical barriers
- the inflammatory response
- protective proteins
innate defenses have no ____________.
recognition of a pathogen , and no memory.
The first line of defense
Skin- an effective deterrent
tears and saliva- contain lysozyme
Ear wax - entraps microorganisms
Mucus- entraps microorganisms
Stomach- highly acidic, inhibits microorganisms
Second line of defense
-Phagocytic cells : white blood cells that surround and engulf invading bacteria
neutrophils, macrophages, eosinophils
- inflammation : redness, warmth , swelling
- natural killer cells : a type of lymphocyte that attacks tumor cells and virus-infected cells
- fever response
Third line to defence
the immune response
characteristics of the immune response
- Recognizes and targets specific pathogens and foreign substances
- Has “memory”- remembers initial exposure and responds more quickly and aggressively on subsequent exposure
- Able to distinguish between “self” body cells and foreign “non-self” invaders or healthy cells and abnormal cells
Antigen
Any substance that triggers an immune response
Two pathways of adaptive immunity :
Cell-mediated and antibody-mediated
T lymphocytes
Cell-mediated
What T lymphocytes do?
Directly attack on specific foreign cells
Coordinate the immune response
Active against parasites, viruses, fungi, intracellular bacteria, cancer cells
B lymphocytes
Antibody-mediated immunity
In antibody-mediated immunity (humoral immunity) , ________
B cells produce antibodies that bind to free antigens in body fluids and neutralize specific antigens
B cells are activate when they recognise
an antigen
B cells can be divided into two cell types which are
memory cells and plasma cells
memory cells
store information for future immune responses
plasma cells
actively secrete antibodies, which will bind to antigen
Antibodies also known as
Immunoglobulins
Classes of antibodies
IgG IgM IgA IgD IgE
IgG
most prevalent in the blood
IgM
first antibody produced in an immune response
IgA
found in body secretions, including breast milk
IgD
function is unclear
IgE
plays a key role in allergic responses
T cells : Cell mediated immunity originate from ______
stem cells in the bone marrow, mature in the thymus
Types of T cells
Helper T-cells
Cytotoxic T-cells
Memory T-cells
Helper T cells
Secrete cytokines, which stimulate other immune system cells
Play a key role in directing the immune response
Are targets of HIV infection
Cytotoxic T cells
Directly attack and destroy abnormal cells and foreign cells
Memory T cells
Reactivate during later exposures
types of immune memory
primary immune response
Secondary immune response
Primary immune response occurs
on first exposure to antigen
Characteristics of primary immune response
Lag time of 3-6 days of antibody production
peal at 10-12 days
Secondary immune response occurs
on second and subsequent exposure to antigen
Characteristics of secondary immune response
- Lag time in hours
- Peak in days
- Much more antibody produced
Active immunization
Intentionally expose individual to form of the antigen that doesn’t produce disease
also known as vaccination
Passive immunization
Administer protective antibodies to an individual
Tissue rejection
May occur following or organ transplant if recipient’s immune system attacks the transplanted tissue
Immunosuppressive drugs
prevent patient’s immune system from attacking transplanted tissue
allergen
any substances that causes an allergic reaction (not a pathogen by the body reacts as though it is a pathogen)
Examples of allergens
Pollen
Bee Venom
Foods
Oil from poision ivy plan
Excessive inflammatory response mediated by
- IgE
- Basophils and mast cells
- histamine
localized
affect only the area exposed
systemic
affect several organ systems
Anaphylactic shock
severe life-threatening systemic reaction (difficulty breathing, circulatory collapse)
Autoimmune disorders
- Inability of immune sytem to distinguish “self” from “non-self”
- Autoantibodies and cytotoxic T cells target the body’s own tissues
Examples of Autoimmune disorders
Lupus eythematosis
Rheumatiod arthritis
Immune deficiency: The special case of AIDS
AIDS: acquired Immune deficiency Syndrome
caused by infection with HIV
HIV targets helper T cells
HIV attaches to CD4 receptors of T helper cell, and gains entry to the cell
