Chapter 7 Flashcards
Lymphatic and immune system
Has the lymphatic vessels and organs
- the lymphatic system and the immune system are so strongly associated with one another that the two are virtually indistinguishable.
Lymphatic system
A system of vessels, cells, and organs that carry excess fluids to the blood stream and filters pathogen fro the blood.
Lacteals
Lymphatic capillaries that transport dietary lipids and fat-soluble vitamins to the blood stream.
Provide two examples of connections between the lymphatic and immune systems
- swelling of the lymph nodes via the lymphatic vessels
- transport of lymphocytes via the lymphatic vessels
Functions of the lymphatic and immune systems
Homeostasis mechanism
Absorption and transportation: fats, proteins, fat-soluble nutrients (A, D, E, and K), other nutrients
Fluid balance - drains excessive interstitial fluid
Hematopoiesis - formation of new blood cells
Immune function
Interstitial fluid (IF)
Fills the spaces between the cells, is not the simple fluid that it seems to be
- interstitial fluid and blood plasma together constitute the extracellular fluid compartment of the body (internal environment of the body)
Passages
Lymph
Pump
Lymph vessels
Fluid
Skeletal muscles
Lymphatic vessels
“Lymphatics” - originate as microscopic blind-end vessels called lymphatic capillaries
Lymphatic capillaries
- consist of a single layer of flattened endothelial cells
- slightly larger than blood capillaries
- allow interstitial fluid to flow in but NOT out
Lymphatic anatomy
Lymph vessel resemble veins in structure with these exceptions:
- lymphatics have thinner walls
- lymphatics contain more valves
- lymphatics contain lymph nodes located at certain intervals along their course
Lymph and interstitial fluid together
- lymphatic networks are in the intercellular (interstitial) spaces and are widely distributed throughout the entire body. - however they are not located throughout the whole body
- As a rule: lymphatic and blood capillary networks lie side by side but are always independent of each other.
The two lymphatic collecting ducts
Thoracic duct- the main collecting duct of the lymphatics, received lymph from the whole body, EXCEPT THE UPPER RIGHT QUADRANT
Right lymphatic duct - drains lymph from the upper right quadrant of the body
Lymphatic pump
- there is no muscular pumping organ connected with the lymph system.
-However, the movement of blood, keeps lymph moving slowly throughout the day - lymph flows though the thoracic duct and renters the general circulation (3 liters per day)
Lymphokinesis:
Movement, or flow of lymph
- the two primary mechanisms are?
Skeletal
Thorax (inspiration)
Lymph nodes
Lymph nodes are reticular “lymph glands”
- oval/bean shaped structures (1-2.5mm), that act like filters
- located in intervals along the lymphatic vessels
- remove microorganisms, debris, and abnormal cells.
- nodes are composed of connective tissue, macrophages, and lymphocytes. They act as filters, to cleanse the lymph as it passes through them
Lymph enter and exits nodes how
Lymph moves into a node by way of afferent lymphatic vessels and emerges by one or more efferent vessels
Sinus channels
Sinus channels slow the lymph flow
Reticuloendothelial cells
- mechanical filtration
- biological filtration (phagocytosis)
Tonsils are?
Masses of lymphoid tissue
Located in the pharyngeal lymphoid ring
First line of defense: filter food and air entering the throat
Types of tonsils
Palatine tonsils
Pharyngeal tonsils
Lingual tonsils
Thymus is?
Primary organ of the lymphatic system, two lobed; unpaired organ
Play a critical role in the fight against infection: has the site of maturation of T-cells (lymphocytes)
The thymus secretes what
Thymosin and thymopoietin
The spleen
The largest lymphatic organ
Located in the left abdominal cavity
Diseases that cause spleen enlargement involve: infectious mononucleosis, leukemia
The two regions of the spleen
Red pulp: removes old and damaged red blood cells. Is temporary blood storage
White pulp: contains lymphocytes, searching pathogens
Defense mechanisms include
Barriers to entry or ways of expelling or neutralizing pathogens (disease-producing microorganisms) before they do harm
- skin, stomach, acid, tears, vomiting
Nonspecific defense mechanisms
Phagocytosis, inflammation
Specific defense mechanisms
Immune response enables body to recognize and remove specific bacteria, other foreign cells, viruses
- antibodies
- T-cells
Disease-causing agents include?
Living organisms: bacteria, fungi, parasites
Bacteria: unicellular prokaryotes
Fungi: unicellular and multicellular eukaryotes
Parasites: unicellular and multicellular eukaryotes
Non living infectious “particles”
-viruses
-prions
Bacteria
Characteristics - prokaryotic (no membrane enclosed nucleus, non - membranous), single-celled, uses a variety of resources for growth and reproduction
Infections can be caused by: pneumonia, tonsillitis, tuberculosis, botulism, toxic shock syndrome, syphilis, Lyme disease, etc.
Bacteria can generally be treated with what?
Antibiotics
Viruses
Extremely small, much smaller than bacteria
- living? Open to debate, unable to reproduce outside of a host cell; have no metabolic activity
- contain DNA or RNA, not both
Disease casued by viruses include: AIDS, hepatitis, encephalitis, rabies, influenza, colds, warts, chicken pox, Ebola, hemorrhagic fever
Prions
Infectious proteins
Normal proteins that are not folded correctly, the mid-folding become self-propagating which fills and disables the cell with protein debris
- can resist cooking, freezing, drying
-disease include, Bovine spongiform encephalitis (BSE, “mad cow disease”), Variant Creutzfeldt-Jakob disease (vCJD)
Transmissibility
How easily a pathogen is passed from person to person
Mode of transmission
Respiratory, fecal-oral, body fluids, direct contact
Virulence
How much damage is caused by the infection
The two major categories of immune mechanisms
Innate immunity - in place or already present, the immunity we are born with, is “nonspecific immunity” provides a general defense
Adaptive immunity - responds to and changes to a specific threat, this is the immunity that you develop over time, “specific immunity” providing targeted defense
First line of defense:
Barrier defenses: “mechanical and chemical barriers” (aka: skin and mucous)
Epithelial barriers: stop things from getting inside our body
Chemical barriers; mucous= traps pathogens; hydrochloride acid= GI mucosa = destroy pathogens
Skin
Tears and saliva
Ear wax
Mucus
Stomach
Vagina
Vomiting, urination, defecation
Resident bacteria
Skin - An effective deterrent
Tears and saliva - Contain lysosome (antibacterial enzyme)
Ear wax - Entrap microorganisms
mucus - Entrap microorganisms
Stomach - Highly acidic, inhibits microorganisms
Vagina - Slightly acidic, inhibits some microorganisms
Vomiting, urination, defecation - Remove microorganisms
Resident bacteria - Outcompete pathogens
Second line of defense
Inflammatory response
- if/when alien invaders break through the mechanical and chemical barriers inflammation occurs
- Swelling, redness, heat, fever, etc. (“nonspecific defense”)
Define chemotaxis
Cells release chemicals to attract WBCs
Third line of defense
Adaptive immunity
Characteristics - recognizes and targets specific pathogens and foreign substances - has “memory” - “remembers” initial exposure and responds more quickly and aggressively on subsequent exposures
- able to distinguish between - “self” cells and foreign, “non-self” invaders
- healthy cells and abnormal (tumor) cells
Third line of defense contains
Adaptive immunity
Lymphocytes:
B lymphocytes - “B-cells”
T lymphocytes - “T-cells”
Natural Killer cells - “NK cells”
Antigen
Any substance that triggers an immune response (cell markers)
- usually protein or polysaccharide on outer surface or invading cell or virus
- MHC (major histocompatibility complex) proteins
- Self-antigens that are on human cell surfaces, enabling recognition of “self”
- enable immune system to distinguish “self” from “non-self”
B lymphocytes
Antibody-mediated immunity
- antibodies: proteins made by B lymphocytes that bind with and neutralize specific antigens
- active against viruses, bacteria, and soluble foreign molecules
T lymphocytes
Cell-mediated immunity
- directly attack foreign cells
- coordinate the immune response
- active against parasites, viruses, fungi, intracellular bacteria, cancer cells, cells with “non-self” MHC
Adaptive immunity
Cell-mediate immunity: “cellular immunity”
T-cells: originate from stem cells in the bone marrow, mature in the thymus, attack pathogens more directly, at the cellular level
Primary immune response
Occurs on first exposure to antigen
Characteristics - lag time of 3-6 days for antibody production, peaks at 10-12 days
Secondary immune response
Occurs on second and subsequent exposure or antigen
Characteristics - lag time is hours, peaks in days, much more antibodies produced
Immunization
Immunization - a strategy for causing the body to develop immunity to a specific pathogen
Active - intentionally expose individual to a form of the antigen that doesn’t produce disease (vaccine): also know as a vaccination
Passive - adjuster protective antibodies to an individual
Allergies
Hypersensitivity reactions; inappropriate response to an allergen
Allergen: an substance (antigen) that causes and allergic reaction (not a pathogen, but the body reacts as though it is a pathogen)
Examples of allergens:
Pollen
Bee venom
Foods (nuts, seafood)
Oil from poison ivy plant
