Chapter 14- Host defenses Flashcards
first line of defense
surface protection; blocking microbe entry from penetrating body compartments; doesn’t change throughout life
~innate; non-specific
*Physical barriers
*Chemical barriers
*Genetic barriers
second line of defense
cellular & chemical system that comes into play if infectious agents make it past surface defenses; protective cells and fluids that work throughout your body; includes white blood cells; fights infection in a non-specific way; doesn’t change throughout life
~ innate & nonspecific; system-wide
*Inflammatory response
*Interferons
*phagocytosis
*Complement
third line of defense
specific host defenses that must be developed uniquely for each microbe through the action of specialized WBC; has to learn/exposure, not born with it…
~Acquired, specific; system-wide
*B & T lymphocytes
*Antibodies
*Cytotoxicity
reticuloendothelial system [RES]
a network of fibers and phagocytic cells [macrophages] that permeates tissue of all organs
ex) Kupffer cells in liver sinusoids, alveolar phagocytes in the lung, microglia in nervous tissue
AKA mononuclear phagocyte system
Leukocytes
white blood cells WBC; primary infection-fighting blood cells
Lymphocytes
2nd most common form of WBC
Erythrocytes
red blood cells involved in the transport of O2 [primarily oxygen] and cO2
*lack nucleus= biconcave look
Lymph nodes
small organs located in clusters around body [pits, groin, neck, abdomen region], filter microbes/cancer cells from lymph fluid
*Swell with infection
Extracellular fluid
any fluid outside a cell
*typically where microbes are found initially when they invade the body
What is the most common white blood cell and its primary function?
neutrophil- phagocytes [engulf foreign invaders, cell debris that are smaller than them]
What is the primary function of neutrophils?
phagocytosis
what is the most common phagocyte in the body?
neutrophil [also most common WBC]
which of the following would TLRs [toll-like receptors] NOT recognize?
Peptidoglycan
Lipopolysaccharide
dsRNA
Antibodies
Antibodies
[TLRs are about non-specific host system]
interferons protect against:
viruses
Describe physical barriers, nonspecific chemical defenses, and genetic defenses.
Physical
*Skin- made of a thick, tough keratin layer which is an insoluble protein, making skin water-resistant (not water-proof).
*Hair shafts- keep microbes from growing by shedding hair
*Mucocutaneous membranes- moist & permeable; a happy place for microbial growth (mouth, ears, eyes, genitals)… flushed with fluids like saliva, tears, urine
*Ciliary defense of respiratory tract; nasal hairs trap particles; cilia are cellular extensions and connected to tubulin of cells, so they can actively brush things along
*Coughing & sneezing [airflow], pooping & vomiting
Sweat glands- flushing effect removes microbes
Chemical
*Acidic pH in the stomach acid = inhibits microbes/kills some
*Digestive enzymes found in bodily fluids, including lysozyme [degrades peptidoglycan in cell wall]
*Defensins- damage cell membranes > lysis
*Sweat glands- acidic pH and high salt > inhibits microbial growth
Genetic
*Genetic makeup differences may ensure protection from some pathogens
*Genetic mutation [some people not affected by HIV; mutation for sickle cell - resistant to malaria]
what are the components of unclotted VS clotted whole blood?
*Unclotted whole blood
-Blood plasma- liquid portion of unclotted blood; mostly water, importantly also contains antibodies, nutrients, gas, fats, co2, clotting factor, waste
-buffy coat- WBC
-red blood cells
*Clotted whole blood-
-serum=liquid blood portion after clotting ; free floating anti bodies
-Blood cells [clot] = made by process of hematopoiesis in bone marrow by stem cells
What are the 4 types of granular and 4 agranular leukocytes?
*Granular
Neutrophil
Eosinophil
Basophil
Mast cells
*Agranular
Monocytes
T lymphocytes
B lymphocytes
Natural killer NK cells
Eosinophils- Function
*Destroy large eukaryotic pathogens like helminths, fungi; bump up against them and release digestive enzymes; can destroy body tissue
*Also involved in allergy and inflammation
Basophils Primary Function
release histamine, involved in allergies and inflammation
Mast cells
look and function similar to basophils, but they are bound to connective tissue, and not found in blood
*local inflammatory reactions and allergies
Describe the function of T VS B lymphocytes
B cells- produce antibodies upon activation by antigens
T cells- involved in destroying foreign material
Monocytes
released into blood then differentiate/mature into:
A) macrophage- roam bloodstream, phagocytosis, antigen processing, immune system regulation
or
B) dendritic cells- similar fx but reside throughout the mononuclear phagocyte system
platelets
small cell fragments originate in bone marrow
~involved in blood clotting and inflammation
[larger than clotting factor molecules]
What are the major functions of the lymphatic system?
*Provides an additional route for the return of extracellular fluid to the circulatory system
*Helps drain fluid that has accumulated due to inflammatory response
*Render surveillance, recognition, and protection against foreign materials through a system of lymphocytes, phagocytes, and antibodies
Identify the lymphatic structures
*Lymphatic fluid- plasma like liquid carried by lymphatic circulation; made of water, dissolved salts, 2-5% protein (like antibodies & albumin); transports WBC & materials
*Lymphatic vessels- vessels that transport lymph; flows in 1 direction, moving from extremities toward heart, eventually back to the bloodstream;;; moved only thru the contraction of skeletal muscles that surround lymphatic ducts
*Lymph organs
Primary organs- lymphocytes are formed/reside; sites of origination and maturation of lymphocytes- cells are released to populate the secondary lymph sites
~~Thymus gland- makes T cells
~~Bone marrow
Secondary organs- microbes and immune responses encounters
~~Lymph nodes- small organs located in clusters around body [pits, groin, neck, abdomen region], filter microbes from lymph fluid
~~Spleen- part of the blood circulatory system; removes worn-out red blood cells; can swell up during infection;
~~MALT- mucosal-associated lymphoid tissue [located in mucous membranes]
~~GALT- gut-associated lymphoid tissue (ex) Peyer’s patches)
steps of inflammation
*Injury
*Rubor, calor [redness, heat]
*Tumor [swelling]
*Dolor [pain]
*loss of function [scab forms]
What are the 7 sequential events in phagocytosis?
- chemotaxis by phagocyte
- adhesion of bacteria
- engulfment into the phagocytic vacuole
- phagosome
- phagolysosome formation
- killing & destruction of bacterial cells
- release of residual debris
Complement system
a series of proteins that work as a cascade to eventually form open holes on any bacterial cell membranes & enveloped viral particles; non-specific
[2nd line of defense]
The chemical found in tears and saliva that hydrolyzes the peptidoglycan in certain bacterial cell walls is
lysozyme.
The body region where a ciliary escalator helps to sweep microbes trapped in mucus away from that body site is the
respiratory tract.
Specificity and memory are associated with which body defense mechanism?
T-cell and B-cell responses
Components of the first line of defense include all the following, except
-nasal hairs.
-flushing action of tears and blinking.
-flushing action of urine.
-phagocytic white blood cells.
-the tough cell sheet of the upper epidermis of the skin.
phagocytic white blood cells.
PAMPs are molecules shared by many microorganisms but not present in :
mammals.
The 2 key phagocytic cells of the body are the
neutrophils and macrophages.
All of the following are types of granulocytes because they have prominent cytoplasmic granules when stained, except
neutrophils.
basophils.
eosinophils.
monocytes.
monocytes.
Plasma B-cells do what?
produce and secrete antibodies.
Which cell type is phagocytic and can migrate out into body tissues to differentiate into macrophages?
monocytes
Hemopoiesis is the
production of white blood cells, red blood cells, and platelets.
Which white blood cells are particularly attracted to sites of parasitic infections?
eosinophils
The blood cells that particularly target parasitic worms and fungi are
eosinophils.
All of the following are types of agranulocytes because they do not have prominent granules in their cytoplasm when stained, except
basophils.
The most numerous WBCs, that have multilobed nuclei and are very phagocytic are
neutrophils.
Which structures are found along lymphatic vessels but are heavily clustered in the armpit, groin, and neck?
lymph nodes
Which gland shrinks in size during adulthood, and has hormones that function in maturation of T-lymphocytes?
thymus
Which of the following lymphoid organs has the immunological function of filtering pathogens from the blood?
spleen
Due to the way the lymph drains from lymph nodes, cell and products of immunity continually:
enter the cardivascular system.
Maria was scratched on her arm by her cat and the site is experiencing rubor. This means
redness.
All of the following can be recognized by toll-like receptors, except
host cell membrane proteins.
single-stranded viral RNA.
lipopolysaccharide.
lipoteichoic acid.
flagellin.
host cell membrane proteins.
The membrane attack stage of the complement cascade involves
the assembly of a ring-shaped protein that forms holes in membranes.
First line of defense: chemical
*Digestive enzymes found in bodily fluids-
what does lysozyme do?
degrades peptidoglycan in cell wall
First line of defense: chemical
*Digestive enzymes found in bodily fluids-
What do defensins do?
damage cell membranes > lysis
