4/19 Lecture E1 Flashcards
What is the normal arterial blood pH?
7.35-7.45
What is the normal arterial blood PCO2?
40 mm Hg (37-43)
What is the normal arterial blood PO2?
95 mmHg
What monitors the composition of CSF and blood?
chemoreceptors
What is the most potent stimulus for breathing?
pH
What is the least potent stimulus for breathing?
O2
Where are the central chemoreceptors located?
the medulla
What % of the change in respiration induced by pH shift is produced by central chemoreceptors?
75%
___ does not cross the BBB well.
H+
What crosses the BBB, reacting with water in the CSF to produce carbonic acid?
CO2
What stimulates the chemoreceptors when CO2 crosses the BBB?
H+
What % of the change in respiration induced by pH shift is produced by peripheral chemoreceptors?
25%
What is acidosis?
blood pH lower than 7.35
What is alkalosis?
blood pH higher than 7.45
What is hypocapnia?
PCO2 less than 37 mm Hg
What is the most common cause of alkalosis?
hypocapnia (usually from increased RR)
What is hypercapnia?
PCO2 greater than 43 mm Hg
What is the most common cause of acidosis?
hypercapnia (usually from decreased RR)
What can be a corrective homeostatic response to metabolic acidosis?
hyperventilation: rids the body of CO2 faster than the body can produce it. Reduces H+ (acid!) by reducing carbonic acid
What can be a corrective homeostatic response to metabolic alkalosis?
Hypoventilation: allows CO2 to accumulate in body fluids faster than exhaled, raising the H+ concentration by raising the concentration of carbonic acid
what are some causes of metabolic acidosis?
uncontrolled diabetes; increased intake of alcohol; antifreeze, aspirin, or methanol poisoning; renal failure
What can cause metabolic alkalosis?
increased vomiting, increased use of antacids
What type of cancer accounts for more deaths than any other form of cancer?
Lung cancer
What is the most important cause of lung cancer?
smoking
What is the most common form of lung cancer?
squamous-cell carcinoma
How does lung cancer first start to form?
The transformation of bronchial ciliated pseudostratified columnar epithelium into stratified squamous. The dividing cells invade the bronchial wall, causing bleeding lesions. Keratin replaces functional respiratory tissue
Where does adenocarcinoma originate?
in mucous glands of lamina propia
What is the least common, but most dangerous form of lung cancer?
small-cell (oat cell) carcinoma
Where does small cell carcinoma originate?
In primary bronchi, invades mediastinum, metastasizes quickly to other organs.
Where does most small cell carcinoma originate? (90%)
mucus membranes of large bronchi
What is atelectasis?
collapse or closure of a lung
What is often the first sign of small cell carcinoma cancer?
coughing up blood
Where are the common sites that small cell carcinoma metastasizes to?
pericardium, heart, bones, liver, lymph nodes, brain.
What is the prognosis of small cell carcinoma after diagnosis?
only 7% of patients survive 5 years.
What are three characteristics that distinguish adaptive immunity from innate immunity?
1) systemic effect: effects the entire body
2) specificity: immunity is directed against a particular pathogen
3) memory: when re-exposed to the same pathogen, the body reacts so quickly that there is no noticeable illness
What are two types of adaptive immunity?
1) cellular
2) humoral
What do lymphocytes do in cellular immunity?
They directly attack and destroy foreign cells or diseased host cells
What is cellular immunity?
A form of specific defense in which T lymphocytes directly attack and destroy diseased or foreign cells
Does humoral immunity involve B cells or T cells?
B cells
What is humoral immunity?
immunity mediated by antibodies that do not directly destroy a pathogen, but tag it for destruction. Antibodies are dissolved in body fluids.
In what circumstance is humoral immunity working?
can only work against the extracellular stages of infections by microorganisms
What is an antigen?
any molecule that triggers an immune response
what are antigens composed of?
proteins, polysaccharides, glycoproteins, glycolipids
What are epitopes?
antigenic determinants: certain regions of an antigen molecule that stimulates immune responses
What are haptens?
too small to be antigenic in themselves. They are molecules that combine with a host macromolecule and create a complex that the body recognizes as foreign. The hapten alone could trigger a response on the next exposure.
What are examples of haptens?
cosmetics, detergents, industrial chemicals, poison ivy, penicillin, and animal dander
What is an immunoglobulin?
an antibody; a defensive gamma globulin found in blood plasma, tissue fluids, body secretions, and some leukocyte membranes.
What is an antibody monomer?
the basic structural unit of an antibody
What are antibody monomers composed of?
4 polypeptide chains linked by disulfide bonds: two heavy chains (400 aa long) and two light chains (200 aa long)
Where do antigens bind to the antibodies?
at the variable region: one in each of the 4 chains
What part of the antigen binds to an antibody?
the epitope
What is the Constant region of an antibody?
region that has the same aa sequence within one person and determines the mechanism of antibody action.
What are antibody classes named for?
the structure of their C region
IgA monomer
monomer in plasma; dimer in mucus, saliva, tears, milk, and intestinal secretions
What does the IgA monomer prevent?
pathogen adherence to epithelia and penetrating underlying tissues
What does the IgA antibody class provide to newborns?
passive immunity
What is an IgD antibody class?
B cell transmembrane antigen receptor
What is an IgE antibody class?
transmembrane protein on basophils and mast cells
What does an IgE antibody class do?
stimulates the release of histamine and other chemical mediators of inflammation and allergy. Attracts eosinophils to parasitic infections. Produces immediate hypersensitivity reactions
What % is IgG antibody class of all antibodies?
constitutes 80% of circulating antibodies
What does the IgG antibody do?
crosses placenta to fetus, secreted in secondary immune response, complement fixation (long term memory)
Where can you find IgM antibodies?
Its a pentamer in plasma and lymph
When are IgM antibodies secreted?
They are secreted in primary immune response, agglutination, complement fixation (early short term memory)
What is somatic hypermutation?
When B cells in lymph nodules rapidly mutate creating new DNA sequences
What are the 3 major cells of the immune system?
1) lymphocytes
2) macrophages
3) dendritic cells
Where are lymphocytes especially concentrated?
lymphatic organs, skin, and mucous membranes
What are the three categories of lymphocytes?
1) NK cells (immune surveillance)
2) T lymphocytes
3) B lymphocytes
Where do B cells mature?
in bone marrow
Where do T cells mature?
in the Thymus
What do B cells become in lymph nodes?
plasma cells
Where do B cells go after they become plasma cells?
They then go back to bone marrow (and other lymph organs) to secrete Antibodies
Where do mature T cells go?
Back to bone marrow or to other lymph organs
What 4 classes of T cells are used in cellular immunity?
1) cytotoxic
2) helper
3) regulatory
4) memory
What are the three stages of cellular and humoral immunity?
1) recognition
2) attack
3) memory
What are the three “r’s” of immunity?
1) recognize
2) react
3) remember
What are the two aspects of recognition in cellular immunity?
1) antigen presentation
2) T cell division
What happens during antigen presentation? (4)
1) APC encounters and processes an antigen
2) APC migrates to the nearest lymph node
3) APC displays it to the T cells
4) When T cells encounter a displayed antigen on the MHC protein, they initiate the immune response
What role to Helper T cells play in the attack phase of cellular immunity?
When helper T cell recognizes the Ag-MHC protein complex, it secretes interleukins and exert three effects:
1) attract neutrophils and NK cells
2) attract macrophages, stimulate their phagocytic activity, ad inhibit them from leaving the area
3) stimulate T and B cell mitosis and maturation
What do cytotoxic T cells do?
directly attack other cells
in cellular immunity, which cells become memory cells? Why?
Some Tc and Th cells: because they are long lived and require fewer steps to be activated (more rapid response!)
What is the T cell recall response? (2 steps)
1) upon re-exposure to the same pathogen later in life, memory cells launch a quick attack so that no noticeable illness occurs
2) the person is immune to the disease
Which is more indirect: humoral or cellular immunity?
humoral
How is humoral immunity different than cellular?
B lymphocytes produce antibodies that bind to antigens and tag them for destruction by other means, cellular immunity attacks the enemy cells directly
humoral immunity recognition
B cells digests antigens and then displays them on the cell surface
humoral immunity attack phase
antibodies bind to antigen and “tags it” for destruction
memory in humoral immunity
some B cells differentiate into memory cells
What are the 4 mechanisms that antibodies have for attack against antigens?
1) neutralization
2) complement fixation
3) agglutination
4) precipitation
What is the neutralization mechanism?
antibodies mask pathogenic region of antigen
What is the complement fixation mechanism?
1) IgM or IgG bind to antigen, change shape and initiate complement binding which leads to inflammation, phagocytosis, immune clearance, or cytolysis
2) primary defense against foreign cells, bacteria and mismatched RBCs
What is the agglutination mechanism?
1) antibody has 2-10 binding sites; binds multiple enemy cells, immobilizing them from spreading
2) enhances phagocytosis by created “bigger bites”
What is the precipitation mechanism?
antibody binds antigen molecules (not cells); creates antigen-antibody complex that precipitates, allowing them to be removed by immune clearance or phagocytized by eosinophils
What is a primary immune response?
immune reaction brought on by the first exposure to an antigen
