WEEK 3 Qs
describe the lateral wall of the nasal cavity
- conchae (inferior, middle, and superior). the spaces in between are the meatuses. - sphenopalatine foramen lies behind superior concha - maxilla - perpendicular plate of palatine - ethmoidal labyrinth - lacrimal bone
describe the medial wall of the nasal cavity
- nasal bones - perpendicular plate of ethmoid - vomer - nasal septal cartilages
structure of influenza
- segmented (-) strand RNA genome - HA and NA are protein spikes - Nucleocapsid protein (NP) surrounding genome directly - Cap and RNA polymerase on genome
factors that affect blood flow
-Blood pressure -Vascular resistance -Venous return -Velocity of blood flow - viscosity - cardiac output
development of paranasal sinuses
-develop during late fertal life and after birth -enlarge during eruption of permanent teeth and after puberty - lined by resp epithelium, mucus secretions drain into nasal cavity. - lighten skull and add resonance to voice. - frontal, maxillary, and sphenoid
generations of the resp system
0-16: conducting zone 16-19: terminal bronchioles 16-23 resp zone
For O2 at 37 degrees C, solubility is 0.03 ml (STDP) plasma/ mmHg. How much oxygen is dissolved if PO2 is 100 mmHg? If PO2 is 670 mmHg??
0.03 x 100 = 3 ml/L. and 0.03 x 670 = 20.1 ml/min
lung defenses
1. , nose hair nasopharyngeal filter w/ cilia and conchae to catch large particles. gag and Cough reflex stop aspiration of microbes from nasopharynx. microcilliary blanket. goblet cells which produce mucin in 2 stages (watery and gel-like) 2. (innate system) bronchial lymphoid tissue which produces IgA which prevents microbes from binding to epithelial cells. IgM, igG, macrophages to phagocytose.
anatomy of larynx
1. Hyoid bone 2. Hyaline cartilages: - Thyroid - Cricoid - Inferior part of arytenoids 3. Elastic cartilages: - Epiglottis -Corniculate -Cuneiform - Superior part of arytenoids 4. Ligaments (vestibular and vocal) 5. Skeletal muscle - needed for the various movements that are required for making noise and vocalisations
3 parts of nasal cavity
1. Vestibule - Stratified squamous keratinized epithelium 2. Nasal cavity and conchae (labyrinth) - Respiratory epithelium 3. Cribriform plate - Olfactory epithelium - neural epithelium with the receptors for the sense of odours
name the steps for HIV infiltration
1. attachment 2. fusion 3. reverse trasncriptase 4. integration into host DNA 5. transcriptase (Host polymerase makes viral mRNA) 6. translation (viral mRNA is used to make structural proteins and viral enzymes) 7. products of translation will be assembled and released outside of cell. virus steals lipids from the host cell wall to build its own outer membrane. 8. maturation (viral protease cleaves gp160 into gp120 and gp41)
types of blood flow control
1. neural 2. humoral 3. metabolic 4. flow-mediated vasodilation
NRTIs lack the
'3-OH required for DNA elongation so doesn't allow from 3-5 phosphodiester bond. These nucleoside analogues prevent DNA polymerization!!
alveolar period
(8 months to childhood) Mature alveoli have well-developed epithelial endothelial (capillary) contacts.
calculate alveolar ventilation
(tidal volume - dead space) x respiratory rate
how does respiratory exchange ratio change during moderate exercise
- During exercise for a moderately fit subject VO2 can increase to 4L/min and VCO2 can increase to 8L/min, and as such R can increase to >1 After exercise, ventilation does not return to basal levels until oxygen debt is paid, and R can fall to 0.5 or less (increased oxygen consumption to replace myoglobin) before returning to normal values
HIV diagnosis
- ELISA/Western blots test look for antibodies to viral proteins, but can give false negatives in the first 2 months of infection. - HIV PCR/viral load tests allow the physician to monitor drug effects on viral load. - CD4 count (>500 beginning stages)
Influenza viruses can cause endemic, epidemic and pandemic infections. Which type of influenza virus is associated with pandemics and what specific events lead to a pandemic infection?
- Influenza A causes pandemics. Influenza B and C do not. * Pandemics are due to antigenic shift. - Antigenic shift is a major change in the antigenicity of the haemagglutinin (H) and/or Neuraminidase (N) antigen of Influenza A. *The major change in the H and/or N means that the new strain can spread through populations because individuals only have immunity to strains of influenza that they have been exposed to previously. The lack of serological cross-reactivity means that these new viruses can cause pandemics. *differentiate from antigenic drift; which is due to mutations during DNA/RNA replication. The result are viruses that belong to the same subtype, showig serological cross-reactivity but may not cross-react completely. This occurs to Influenza A and B, and may cause epidemics. - Pandemic infections are a result of: i) genetic reassortment between 2 different virus strains when they infect the same host cell. Often this reassortment occurs between a human influenza strain and an avian influenza strain; or ii) zoonotic transmission of an avian or mammalian strain directly to humans, e.g. transmission of avian H5N1 and H9N2 strains in Hong Kong in 1997; or iii) Emergence of influenza strains that caused epidemic many years previously, e.g. Russian influenza H1N1 caused an epidemic in 1950 and a world wide pandemic in 1977.
theories of short term control of blood flow
1. oxygen lack theory: when tissue metabolism goes up, the tissue uses more oxygen. There is less oxygen available to the muscle in the sphincters, which forces them to relax and open in capillary 2. vasodilator theory: greater metabolic rate or lower O2 available, the greater the vasodilator substances released (adenosine, CO2, histamine, K+, H+) i.e when too little O2 is supplied to the myocardium, adenosine is released and returns blood flow to normal
mean pulmonary artery pressure
15 mmHg. This is relatively low. low resistance allows for the pulmonary system to pump the entire cardiac output at low pressures. - allows for distribution of blood to peripheral alveoli
total volume of conducting zone
150 ml - this is the physiological dead space
Canalicular period
16-26 weeks, terminal bronchioles divides into respiratory bronchioles, capillary beds associate with alveolus
cm excursion of diaphragm during quiet breathing vs forced
1cm vs 10
percentage of immune system in peripheries vs lymphoid tissue
2% in peripheral. 98% in lymphoid tissue and organs
At normal [Hb] of 15g/100mL - oxygen capacity:
20%
what percentage of blood cultures are actually accurate for CAP?
20-30%
When do antibody levels become detectable in HIV
23-90 days after exposure. These levels eventually plateau
normal tidal volume
500 mL
PrEP has decreased new infections in syndney by how much?
60%
Mixed venous O2 saturation
60-80%
How long does HIV particle live in blood?
6hrs
what percentage of rhinovirus infections are asymptomatic?
75%
relative amount of CO2 in each form
90% of HCO3, 5% dissolved, 5% of carbamino compounds
gas dilution test
A person breathes from a container containing a known amount of a gas (i.e., oxygen or helium). The test measures how the concentration of the gases in the container changes due to breathing.
why are there high mutation rates in HIV
they don't have the same check points as host cells are are highly susceptible to mutation. This allows the virions to bypass the immune system
tenefovir moa
A nucleotide analog of adenosine monophosphate First nucleotide reverse transcriptase inhibitor Inhibits viral reverse transcriptase side effects: headache, GI issues
describe the pleural recesses
costomediastinal pleura, which lie between the costal pleura and the mediastinal pleura and the costodiaphragmatic pleura, which lie between the costal pleura and the diaphragmatic pleura. In passive inspiration, these recesses are filled by thin films of fluid (pleural fluid). In forced inspiration, the lung will expand to fill up the costomediastinal and costodiaphragmatic recesses.
fungus that causes pneumonia most commonly in immunocompromised patients?
cryptococcus neoformans
With regards to the trachea, which is MOST INCORRECT? a. The trachea is lined by ciliated pseudostratified columnar epithelium with goblet cells. b. Contains horseshoe shaped cartilage rings. c. Has basement membrane beneath epithelium. d. Contains mixed seromucous glands. e. Contains skeletal muscle in its wall.
Answer: (e) (e) trachealis muscle located in the opening of the U-shaped cartilages is smooth muscle (not skeletal), the others are correct
Which of the following is not a relation to the apex of the left lung?a. Superior vena cavab. Left subclavian arteryc. Left recurrent laryngeal nerved. Left trunk of the brachial plexuse. Left stellate ganglion
Answer: A. The superior vena cava is found on the right side of the mediastinum, entering the right atrium. Therefore it would not be a relation to the left lung. It is related to the hilium of the right lung. - Option B is incorrect: the left subclavian artery directly overlies the apex of the left lung as it continues into the axilla, underneath the clavicle. - Option C is incorrect: the left recurrent laryngeal nerve is a branch of the left vagus nerve that loops around the aortic arch and ascends into the thoracic inlet to innervate the larynx. This puts it as a close relation of the left lung apex, and many apical tumours cause compression of this nerve. - Option D is incorrect: the left superior trunk of the brachial plexus arises from the lower cervical vertebra and enters the axilla, meaning that it must pass through the region of the left lung apex. - Option E is incorrect: the left stellate ganglion is located at the level of C7, anterior to the neck of the first rib and just below the left subclavian artery. It is a close relation to the left lung apex, and Pancoast tumours (apical tumours) can cause compression of the stellate ganglion, leading to Horner's syndrome.
Which of the following statements regarding interferon release in the innate defence against viruses is MOST correct? a. Interferon inhibits viral entry into cells b. Protein kinase R reduces the production of viral proteins, and hence inhibits replication c. It primes the immune response by downregulating the expression of MHC I and II molecules d. It leads to the activation of NK cells, which kill cells expressing increased MHC I e. Interferon binds to viral glycoproteins and inhibits viral entry
Answer: B. Protein kinase R is a signalling protein that is expressed upon stimulation of a cell by type-1 interferon. It decreases production of all proteins in a cell (including viral replication), allowing a cell to survive long enough for the adaptive immune system to react. - Option A is incorrect: interferon by itself does not itself inhibit viral entry into cells, as it is a cytokine rather than a surface protein regulating entry into a cell. IFITM is a transmembrane protein that fulfils this role - Option C is incorrect: the immune response is primed by upregulating MHC I and MHC II expression. The MHC surface proteins are important in the adaptive immune response as they will more easily attract cytotoxic CD8+ T cells. - Option D is incorrect: cells with reduced expression of MHC I are targeted by NK cells. A common response of virally infected cells is reduced expression of MHC I, which allows the cell to avoid activation of the CD8+ cytotoxic response. (TLDR: high MHCI --> CD8 attack, low MHCI --> NK attack) - Option E is incorrect: interferon is a signalling molecule and not a neutralising antibody.
Which of the following statements about the histology of the lungs is MOST correct?a. The bronchioles have fibrocartilaginous plates in their wallb. The alveoli contain goblet cells which produce mucusc. The bronchioles are lined with stratified columnar epitheliumd. The type II pneumocytes produce surfactante. The submucosa layer of the bronchioles contains lots of seromucous glands
Answer: D. Type II pneumocytes are glandular cells that produce pulmonary surfactant. Surfactant lubricates the lining of the alveoli to reduce surface tension, ensuring that they keep inflated for gas exchange. - Option A is incorrect: bronchioles are the first division of the airways that do not have cartilage lining their walls. - Option B is incorrect: goblet cells are only found in the respiratory epithelium. The cell populations change at the level of the alveoli into pneumocytes. - Option C is incorrect: bronchioles tend to be lined by simple cuboidal epithelium, especially towards more distal divisions of the airway. Stratified columnar epithelium is a rare histological type, and is usually found in areas that experience abrasive trauma such as the anus and uterus. - Option E is incorrect: while seromucous glands are present in the bronchi, they are lost by the bronchiole stage.
Which of the following is MOST characteristic of influenza virus? a. Antigenic drift is associated with pandemics b. Antigenic shift is more frequent than antigenic drift c. Reassortment and zoonosis are required for antigenic shift d. Point mutations in the gp41 protein cause antigenic drift e. Point mutations encoding haemagglutinin and neuraminidase receptors are responsible for antigenic drift
Answer: C or E. Option C is correct as antigenic shift is defined as a sudden and significant change to the antigens of influenza A, where the surface proteins have no cross-reactivity with previous antibodies. Genetic reassortment and zoonotic transmission (zoonosis) are the main mechanisms through which this occurs. Because of the differences in physiology between animals, influenza from an animal will have very different surface proteins, such that existing immunity will not be able to handle the sudden and significant change (i.e. shift). Once it develops the ability to infect humans, it will be able to cause a pandemic. Option E is also correct as antigenic drift refers to gradual evolution of the influenza virus through progressive point mutations. These occur primarily within the haemagglutinin and neuraminidase, the two surface proteins that trigger the immune response with influenza. - Option A is incorrect: antigenic drift tends to cause seasonal epidemics rather than full-blown pandemics. This is because with gradual mutations, existing immunity still has a degree of reactivity with the new virus. This reduces the transmission of the virus as some of the population will have some immunity. - Option B is incorrect: antigenic shift is fortunately quite rare, as several conditions have to be met. These conditions are: 1) a new influenza virus type has to emerge after more than 10% of its genome is altered. 2) genetic reassortment between the new virus and an existing human virus allows the new virus to infect humans. This requires both viruses to be present in the body at the same time. - Option D is incorrect: the gp41 protein is found in HIV, not influenza.
All of drug the following factors can influence the plasma concentration of a EXCEPT: a. Route of administration b. Genetic variation in rate of metabolism c. Variation in target receptor expression d. Obesity e. Chronic liver disease
Answer: C. Target receptor expression will affect the pharmacodynamics of the drug (effect the drug has on the person), but does not impact the plasma concentration of the drug. - Option A is a true statement: the route of administration affects the bioavailability, i.e. how much of the drug is removed by first-pass metabolism before it enters circulation. - Option B is a true statement: there is genetic variation in the degree of hepatic metabolism, i.e. people express different amounts of cytochrome p450 enzymes that affects their metabolism of drugs. The metabolism impacts how much of the drug is metabolised and removed from the plasma. - Option D is a true statement: lipophilic drugs will also dissolve within fat stores, increasing the overall volume of distribution and concentration of drug in the plasma. Obese people have larger fat stores and will have a greater volume of distribution. - Option E is a true statement: chronic liver disease will impair the amount of hepatic metabolism that can be carried out by the body. This means that plasma concentrations of drugs may be higher than normal due to reduced metabolism.
Mark is a 1 year old boy who has repeated bacterial infections, sinusitis, and pneumonia. Which of the following statements is MOST correct? a. His IgG levels should be checked b. It was unlikely to be an antibody deficiency because he still has passive immunity, since maternal IgG lasts for one year c. This is most likely caused by congenital absence of the spleen d. Check blood film to see if B cells are present e. He should receive a hematopoietic stem cell transplant
Answer: D. A tendency to develop bacterial infections (including sinusitis and pneumonia) is suggestive of a B cell defect (e.g. congenital absence of B cells). This is because the immune response to bacterial infections relies greatly on the production of antibodies by B cells. Antibodies enhance the detection and phagocytosis of bacteria. - Option A is incorrect: checking IgG levels is a good idea as a lack of antibody production may be the reason for his tendency to develop bacterial infection. However, a major confounding factor in his age group is the presence of maternal antibodies (e.g. from breastfeeding). Other tests should be performed instead, e.g. blood film for presence of B cells. - Option B is incorrect: maternal IgG that has passed through the placenta has a variable half-life, and does not always extend up to a year of protection. - Option C is incorrect: congenital absence of the spleen is primarily characterised by increased susceptibility to blood-borne infections and polysaccharide-encapsulated bacterial infections, which can be rapidly fatal. This increased infection risk is due to inability of the body to clear opsonised bacteria from circulation, a process normally performed by the spleen. Asplenia tends to present with sepsis. - Option E is incorrect: this may be a treatment option given his potential to have a B cell deficiency, however the cause of his immunodeficiency should be investigated before a stem cell transplant is considered.
Which of the following statements about the immunology of influenza is MOST correct? a. CD8+ T cells respond to the virus but CD4+ do not b. CD8 T+ cells respond to infection by interacting with MHC IIc. Infected cells are killed by neutralising antibodiesd. Dendritic cells prime CD8+ T cells in the lymph nodese. CD8+ cells kill infected cells via antibody-dependent cellular cytotoxicity
Answer: D. Dendritic cells are antigen presenting cells that bring antigens from the periphery to the nearest lymph node. - Option A is incorrect: both CD8+ and CD4+ cells are involved in the response against viral infection. CD8+ cells help kill infected cells, while CD4+ cells help coordinate the immune response against influenza. - Option B is incorrect: CD8+ T cell receptors interact with MHC I expressed on all cells. If antigens are presented on MHC I the CD8 cell will induce cell death to prevent viral spread. MHC II receptors are expressed on antigen presenting cells (not CD8+ cells) and help facilitate an adaptive immune response. - Option C is incorrect: neutralising antibodies by definition neutralise the pathogen, not an affected cell. This may be by blocking key enzyme pathways needed for survival or blocking surface particles that may act as virulence factors. - Option E is incorrect: CD8+ cells kill infected cells through antibody-independent cell cytotoxicity. They rely on antigen presentation at MHC I cell receptors.
Which of the following investigations is MOST important in the diagnosis of pneumonia? a. Sputum culture b. Spirometry c. Blood test d. Chest X-ray e. Bronchoscopy
Answer: D. Most clinical guidelines view the chest X-ray as the most important investigation in the diagnosis, as it can rule out other respiratory tract infections that may present with similar symptoms (fever, dyspnoea, cough and sputum production etc.). A chest X-ray that shows infiltration into the chest is required to make a diagnosis of pneumonia. - Option A is incorrect: sputum culture is useful for identifying the aetiological agent of a respiratory condition. However, a number of diseases, not necessarily pneumonia, may cause sputum production (bronchitis, bronchiectasis, pulmonary oedema, lung abscess etc.). A sputum culture will not be able to differentiate this from pneumonia. This is also slow, particularly for Mycoplasma. - Option B is incorrect: spirometry assesses abnormalities in airflow, and can be used to distinguish obstructive lung disease (which includes pneumonia) from restrictive lung disease. However there are many obstructive lung conditions that may present similar to pneumonia on spirometry, e.g. acute exacerbations of asthma or COPD. - Option C is incorrect: blood test abnormalities in pneumonia are similar to other acute infections. While they can assist a diagnosis of pneumonia they are not the most important in making a provisional diagnosis of pneumonia. - Option E is incorrect: bronchoscopy may provide additional diagnostic value in patients who do not have sputum production as a symptom, however a chest X-ray remains the most useful in making a diagnosis of pneumonia and ruling out other causes.
fungal infections in HIV
cryptococcus neoformans. can be anywhere in body including brain (meninges), prostate (usual site of reactivation). treatment: Fluconazole (in AIDS patients). CD4 count: <100.
pathogensis of lung abscess
Aspiration of infective material, certain bacterias like klebsiella, septic embolus, infection distal to obstruction like a foreign body, penetrating injury, spread from adjacent organs
pathogenesis of lung abscess
Aspiration of infective material, certain bacterias like klebsiella, septic embolus, infection distal to obstruction like a foreign body, penetrating injury, spread from adjacent organs.
when is alveolar pressure zero?
At three points. Pre-inspiration, end-inspiration, end-expiration.
location of larynx
Attaches to hyoid bone; opens into laryngopharynx; continuous with trachea. c3-c6 in adult males, can be higher in women and children.
Which cells do CD4 T cells stimulate?
B-cells via IL-4,5,6,13 that stimulate maturation of B cells and subsequent production of antibodies. CD8 via IL-2 allows for maturation of CD8 cells into cytotoxic IFN-y stimulates maturation of monocytes into macrophages and triggers phagocytosis of pathogens
Which of the following structures passes over the hilum of the right lung? A. Ascending aorta B. The azygos vein C. The phrenic artery D. The right atrium E. Sympathetic trunk
B. The azygos vein
The hilum of the left lung: A. lies behind the superior vena cava B. is inferior to the arch of the aorta C. has the phrenic nerve passing posterior to it D. is surrounded by tracheobronchial lymph nodes E. is opposite thoracic vertebrae 2, 3 and 4
B. is inferior to the arch of the aorta The arch of the aorta passes over the left hilum and the left main bronchus A. right hilum lies behind SVC C. phrenic nerve passes anteriorly D. located at tracheal bifurcation and anteriorly
At this stage of the battle (see image), which events proceed to clear the infection? A: The innate immune system continues to clear pathogens and has no influence on the acquired immune response. B: Antigen presenting cells only function through uptake and destruction of pathogens during the innate response. C: One of the major differences between MHCI and MHCII is the former is expressed on all cells, whilst the latter is primarily expressed on antigen presenting cells. D: CD8 T cells mediate killing through Pathogen Associated Molecular Patterns presented on infected cells that trigger infected cell death.
C: One of the major differences between MHCI and MHCII is the former is expressed on all cells, whilst the latter is primarily expressed on antigen presenting cells. MHCII is preferentially expressed on antigen presenting cells.
what are the 2 markers for hiv disease progression?
CD4 T cell count and viral load.
once you reached adanced HIV (AIDS) which disorders are you at risk of
CMV, pneumocytic pneumonia, lymphoma
After the lateral plate mesoderm forms what happens?
Clefts appear to spilt solid layer In two. 1. Parietal layer and 2. Visceral layer.
structure of the trachea
Contains 16-20 C-shaped rings joined by fibroelastic connective fiber
hyposplenism
this is the absence or decreased efficiency of the spleen. The spleen functions as the sight of blood filtering, housing of lymphocytes, macrophages, and monocytes, resovoir of blood. Surrounded by a thick CT capsule. Contains red and white pulp. The red pulp is made up of sinusoids and splenic cords. This is the main sight of macrophage and monocyte presence and where filtratrion of blood and removal of damaged red blood cells occur. White pulp contains lymph tissue that surrounds splenic blood vessels. Germinal centers are the sight of lymphocytes maturation (B and T cells).
mucosal findings of HIV
thrush, oral ulcerations, genital herpes, cervical hyperplasia
calculate total ventilation
tidal volume x respiratory rate
minute ventilation
tidal volume x respiratory rate
Morton is a 6-month-old baby with a history of extracellular bacterial infections, most recently a bacterial pneumonia. Which of the following is LEAST CORRECT? A. Morton possibly has a complement defect. B. Possibly a neutrophil defect. C. Possibly a B cell defect. D. Any IgA detected in his blood would be primarily from transplacental transfer. E. He has a primary immunodeficiency
D. Any IgA detected in his blood would be primarily from transplacental transfer.
Which statement is true regard STPD, BTPS and ATPS? A. At ATPS,1 mol of gas is equal to 22.4L B. At BTPS, lung pressure is 760 mmHgC. At STPD, air temperature is at 20 CD. At STPD, water pressure is 0 E. B in BTPS stands for barometric pressure
D. At STPD, water pressure is 0 STPD is standard temperature (0C) and pressure (1 atmosphere), and dry A. 1 mol of gas is 22.4L at STPD B: 760mmHg is STPD 1 atmosphere pressure. The lung pressure should be different for inspiration/expiration ?? C. STPD is 0C (273K) D. B stands for body temperature pressure, saturated
Which of these is most true about the trachea? A. Its lining consists of pseudostratified columnar epithelium with goblet cells B. Its epithelium is made of ciliated simple squamous cells. C. Something about the cartilage rings being completely circular. D. It bifurcates at 5th-6th thoracic vertebrae E. It begins at the superior border of the pharynx
D. It bifurcates at 5th-6th thoracic vertebrae the epithelium is pseudostratified ciliated columnar epithelium with goblet cells. The cartilage rings are semi-circular and it begins at C5.
Tense (T) conformation
DeoxyHb - globin units tightly bound to each other with electrostatic interactions.
Follicular t helper cells
Differentiated T cells expressing CD4 that provide cytokine help to B cells in a germinal center for class switching and somatic hypermutation. - preferentially targeted by HIV
anatomical positioning for speech
During phonation, the vocal folds are brought together by muscles attached to the arytenoids (cricothyroid). As air is forced through the vocal folds, they vibrate and produce sound. By tightening or relaxing the laryngeal muscles, the sounds of your voice can be changed.
Which of the following statements is CORRECT regarding the pressures during a normal breathing cycle? A: Alveolar pressure is always negativeB: Alveolar pressure varies between about - 5 cm H2O and - 8 cm H2O C: Intrapleural pressure is at its most negative at the beginning of inspiration D: The shape of the alveolar pressure trace is essentially the same as the shape of the intrapleural pressure trace E: Alveolar pressure is zero at the beginning of inspiration
E: Alveolar pressure is zero at the beginning of inspiration Alveolar pressure follows flow of air into the lungs; this means zero pressure = zero flow also A: Alveolar pressure is negative during inspiration, and positive during expiration B: varies between -1 and +1cm H2O. - 5 cm H2O and - 8 cm H2O is for intrapleural pressure C: As flow follows alveolar pressure, it is most negative during expiration D: intrapleural pressure becomes more negative during inspiration due to thoracic expansion. Thoracic expansion increases this pressure
Oncogenic viruses:
EBV → non-hodgkin b cell lymphoma, primary CNS lymphoma HHV8 → kaposi sarcoma HPV → squamous carcinoma of cervix and anus.
humoral blood flow control
Epinephrine and norepinephrine, hormones secreted by the adrenal medulla, raise blood pressure by increasing heart rate and the contractility of the heart muscles and by causing vasoconstriction of arteries and veins. These hormones are secreted as part of the fight‐or‐flight response.
bohrs vs fowlers
Fowlers: Fowler's technique measures anatomical dead space through nitrogen concentration analysis of expired air after a single inspiration of 100% oxygen. The inspired gas enters the alveoli, and the last part of this tidal volume stays in the conducting airways (anatomical dead space). bohr's: measures the volume of the lung that does not eliminate co2. This is Physiological DEAD Space. This includes parts that do not participate in gas exchange AS WELL AS any nonfunctional/poorly functioning alveoli due to impaired blood flow.
Which lung capacities include residual volume?
Functional residual capacity and vital capacity functional residual capacity and total lung capacity
congenital diaphragmatic hernia
Incomplete pleuroperitoneal membrane No Bowel sounds in abdomen, mediastinum enlargement. viscera perforate through thorax causing lung compression.
body plethysmography
Individual is enclosed in a small, airtight chamber. The person's nostrils is clipped, and h/she is breathes against a mouthpiece. As the individual breathes, the air pressure and volume in the chamber change in accordance with the movements of the chest wall. This provides an estimate the person's lung volume. P1 x V1 = P2 (V1 - ΔV)
symptoms of influenza A
Inflammation High fevers, chills, muscle pain, lethargy, hacking cough treatment: *oral amantadines. MUST BE GIVEN 24-48 HRS AFTER ONSET. - restance develops rapidly after treatment side effects: dizziness, confusion *zanamivir - inhaled neuroaminidase inhib - w/in 30 minutes of onset - shortens illness by 1.5-2.5
HIV stages
Initial stage: generalized flulike symptoms (4-8 weeks) Latent stage: (2-12 years) asymptomatic HIV infection stage: opportunistic infections; CD4 cells are usually less than 500 cells/mm3 (2-3 years)
Nosocomial pneumonia (hospital acquired)
Klebsiella, E. coli, Pseudomonas aeruginosa, staph aureus, strep pneumonia
most common cause of atypical pneumonia
Mycoplasma pneumoniae
most common cause of atypical pneumonia
Mycoplasma pneumoniae and chlamydia pneumonia
causative agents of atypical pneumonia
Mycoplasma pneumoniae, Legionella pneumophilia. viral: sars-cov2, RSV, influenza A & B, parainfluenza,
how do we measure residual volume?
NOT with spirometry. can use: body plethysmography, gas dilution (using either helium or nitrogen)
How do we measure residual volume?
NOT with spirometry. 1. Body plethysmogrphy 2. Gas dilution (using either helium or nitrogen)
Relaxed (R) Configuration:
O2 binds to iron atom in centre of one sub unit inducing a conformational change in that subunit, this induces other subunits to change to R form making it easier for them to pick up O2.
Relationship between Hb and nitric oxide —>
Oxygenated Hb binds tightly to nitric oxide. SOOO in hypoxic tissues both oxygen AND nitric oxide are released. NO stimulates local vasodilation which directs blood flow and hence oxygen specifically to hypoxic tissue.
advantages and disadvantages of HIV tests
PCR: pros --> detect very early infections before antibodies have been developed. This test may be performed just days or weeks after exposure to HIV. - 99% sensitivity cons --> expensive, Time and labor intensive. ELISA: blood or oral secretions to test for antibodies. pros --> simple procedure, cons --> may cause false neg in early days of infection. Need follow up Western Blot - Inadequate inhibition of immunogenic antigen - takes up to 10 days
iF X is 30% of a mixture of gases and total pressure is 760 mmHg, what is partial pressure of X?
Px = P total x Fx 760 x 0.3 = 228 mmHg
pathogenesis of influenza A and B
Rapid onset. Following respiratory transmission, the virus attaches to and penetrates respiratory epithelial cells in the trachea and bronchi. Viral replication occurs in host cell which is then destroyed. Incubation is 1-4 days. Regeneration of epithelium takes about 3 to 4 weeks. - Hemagglutinin A is cleaved to generate virus particles - epithelial cell death - compromised alveoli - innate cellular infiltration (neutrophils and inflammatory monocytes) - extracellular matrix degradation - excess T cell response
transition from primary bronchi to secondary and tertiary
Respiratory epithelium. gradually becomes simple columnar with fewer cilia. Fewer goblet cells. Fewer glands. Smooth muscle. Irregular hyaline cartilage plates
Respiratory exchange ratio:
Respiratory exchange ration = CO2 output/O2 consumption. Normal value is 0.8-0.85. In short term, R can vary with pattern of respiration (hyperventilation). Long-term R is determined by the food being burned. carbs = 1.0, fat = 0.7.
viruses that cause pneumonia
SARS-COV2, Influenza A and B, RSV, parainfluenza
Why is TAF better than TDF?
TAF achieves higher intracellular concentrations with lower blood levels, resulting in presumably lower rates of renal and bone toxicity compared to TDF. - renal excretion is minor with TAF. - TAF has high antiviral activity at oral doses 10 times lower than TDF doses.
Development of lung buds starts with the formation of which two folds?
The pleuropericardial folds/membranes - fuse with each other and with the root of the lungs. Divide thoracic cavity into definitive pericardial cavity and 2 pleural cavities. And the pleuroperitoneal folds.
Describe the gross anatomy of the trachea and main, lobar and segmental bronchi, accounting for how the structure accounts for the likely location of inhaled foreign bodies to lodge. A detailed labelled diagram is recommended. (7 marks)
The trachea is the main tube that moves air inspired from the nasal cavity into the lungs within the thoracic cavity. It is made of 16 - 20 U-shaped cartilaginous rings with the smooth trachealis making the posterior end of the trachea. It passes through the thoracic inlet and bifurcates into the two principal bronchi (left and right) at the level of T5 and T6 when at rest. The most inferior end of the trachea is the carina, a small ridge that separates the left and right openings into the principal bronchi. The mucous membrane of the carina is the most sensitive area of the trachea, and will trigger the coughing reflex if any foreign material lands on it. The bronchi are airway passages that conduct air from the trachea into the lungs. The first bronchi that branch from the trachea are the principal/main bronchi, which are the widest bronchi and enter the lungs at the hilum. The right main bronchus is wider, shorter and more vertical than the left main bronchus, so foreign particles that enter the lower respiratory tract tend to fall through the right main bronchus instead of the left. The left main bronchus also passes beneath the aortic arch. The principle bronchi then branch into smaller lobar bronchi that supply each lobe of the lung. - For the right lung, the right main bronchus divides into the right upper lobar bronchus and a stem bronchus, which is a continuation of the principal bronchus that later gives rise to the right middle and right lower lobar bronchi. - For the left lung, the left principal bronchus divides into the left upper and lower lobar bronchi as well as the lingular bronchus. The lingular bronchus supplies the lingula, a projection of the left upper lobe that is homologous to the right middle lobe. The lobar bronchi further divide into progressively smaller segmental bronchi. When the airways are too small to be supported by cartilage, they become bronchioles. For the right lung: - The segmental bronchi that arise from the right upper lobar bronchus are classified into anterior, posterior, lateral and apical. - The segmental bronchi that arise from the right middle lobar bronchus are classified into medial and lateral. - The segmental bronchi that arise from the right lower lobar bronchus are classified into superior, anterior, medial, lateral and posterior. For the left lung: - The segmental bronchi that arise from the left upper lobar bronchus are classified into apicoposterior and anterior. - The segmental bronchi that arise from the left lingular lobar bronchus are classified into superior and inferior. - The segmental bronchi that arise from the left lower lobar bronchus are classified into anteromedial, posterior, superior and lateral.
layers of the trachea
Trachea tube consists of 3 layers 1. Mucosa - Respiratory epithelium with goblet cells - Lamina propria: loose, fibroelastic CT with elastic and reticular fibers, lymphoid elements 2. Submucosa Dense irregular fibroelastic CT with serous (darker staining) and mucous (paler staining) glands 3.Adventitia Perichondrium: dense CTCartilage C-rings: hyaline cartilageInvoluntary trachealis muscle: smooth muscle with dense fibrocollagenous CT (between the ends of the C-rings)
difference between true and false vocal cords
True vocal cords - stratified squamous non-keratinised epithelium, has an area of dense connective tissue containing the vocal ligament, and there is also skeletal muscle present here as well
Pseudoglandular stage
Weeks 5 to 17, terminal bronchioles form but respiration is NOT possible.
Regarding the immunology of the influenza virus, which of the following is MOST CORRECT? a. CD8 T cells respond to the virus, CD4 do not b. CD8 T cells responds by interacting with MHC II cells c. Infected cells are killed by neutralizing antibodies d. Dendritic cells prime CD8 T cells in lymph node e. CD8 cells kill infected cells via ADCC
d. Dendritic cells prime CD8 T cells in lymph node e. Antibody-dependent cellular cytotoxicity is one mechanism by which CD8 T cells attack infected cells, particularly in HIV infections due to the CD4+ suppression. CD8 cells however have other mechanisms of action, using MHCI to recognise and kill infected cells.
FVC/FEV1 graph that you had to read measurements off. (FVC = 5L, FEV 1 = 2.5L) Is this different from normal? Explain. (2marks)
Yes, this is different from normal Normal Forced Expiratory Ratio (FEV1/FVC) is 0.7-0.8. This person's Ratio is 2.5/5 = 0.5, therefore lower than normal Indicates obstructive disease e.g. asthma
Which of the following produces the MOST circulating antibodies? a. Long-lived plasma cells in the bone marrow b. Activated B cells in the germinal centres c. Short-lived plasma cells in secondary lymphoid tissue d. Plasma cells on mucosal surfaces e. Naive B cells
d. Plasma cells on mucosal surfaces B cells that undergo somatic hypermutation in germinal centres in lymph nodes/spleen to greatly increase antibody production, antibody binding strength and lifetime. These activated B cells then differentiate into either memory cells or plasma cells. not 100%
3 month old boy. presents with ongoing fungal, viral and bacterial infections. Tests revealed undetectable T cell levels, low IgG, no IgA and high IgM. Which is one of these is MOST correct a. IgG and IgA will be normal after 2 years if untreated b. Circulating neutrophils will be low or absent c. IgA was likely transplacental d. A chest x-ray will be useful in this case e. T cells are involved in IgM production
d. A chest x-ray will be useful in this case Checks for the thymus (a 4yo should show thymic shadow), as well as inspects for pneumonia. If not detected, thymus can be recovered with treatment a. untreated, the boy's IgA levels will remain low due to the absence of CD4 assisted class-switching. IgG (and IgE) are also produced by class switching with help from T cells in germinal centres, so they are also likely to be low. b. neutrophils are likely to be high due to acute infections c. IgG is likely transplacental e. usually T cells are involved in class switching of IgM to IgA
antigenic drift
a mechanism for variation in viruses that involves the accumulation of mutations within the genes that code for antibody-binding sites. - FluA - mechanism: zoonosis and reasortment - population has NO immunity
Plasmacytoid dendritic cells
a type of dendritic cell that produces copious amounts of interferon in response to the detection of viral infection through its Toll-like receptors. also secretes M1P1-B which recruits CD4 cells
Which one of the following is true/is the best general summary regarding the differences between the common cold and influenza? a. Common cold has local symptoms, influenza is systemic b. Common cold is seasonal, influenza is year-round c. Influenza has slow onset, common cold has long onset
a. Common cold has local symptoms, influenza is systemic
tracheoesophogeal fistula
abnormal passageway pertaining to the trachea and esophagus
example of a DNA polymerase inhibitor
acyclovir. A pro-drug that must be phosphorylated into triphosphate before incorporated. Used for herpes
septum transversum will form
central tendon of diaphragm
Formula for compliance
change in volume/change in pressure
Saccular period
characterized by intense vascularization of the lung and loss of its glandular appearance, occurs during the weeks 28 to 36 of gestation. For the first time, close contact between the air spaces and the pulmonary capillaries is established. There is concurrent active development of the lymphatic capillaries. The first true alveoli are present at 34 weeks; gas exchange is possible but not optimal
paranasal sinuses
air-filled cavities lined with mucous membrane, located in the bones of the skull
tidal space
alveolar space + dead space
Regarding residual volume, which of the following statements is the MOST CORRECT? a. It is the volume measured at the normal end-expiratory position. b. It can be measured using helium dilution. c. It can be measured using a body plethysmograph and Charles' Law d. It can be measured using spirometry. e. In an average adult it is 150mL
b. It can be measured using helium dilution. helium is used because it is poorly soluble in blood so closed system in lungs. Nitrogen can be used for dilution also. a. false, after forced end-expiratory position c. Using Boyle's Law (the Boyle was Very Painful) d. no, because residual volume is, by definition, not exhaled e. usually around 1200mL for males, 1000mL for females
olfactory mucosa cells:
basal, supporting, and olfactory receptor cells
oxygenated hemoglobin
bind Nitric oxide tightly, scavenges NO from blood.
why don't we focus on blockig gp120 and cd4 in therapy
binding is reliant on highly variable v3 loop
Side effects of NRTIs
bone marrow suppression, lactic acidosis, peripheral neuropathy, pancreatitis, anemia
In regards to influenza, which is incorrect? a. Influenza has incubation period of 1-3 days and duration of 3-7 days b. Antigenic shift occurs rarely in individuals who are infected with two strains of influenza c. In an epidemic, a new influenza A subtype replaces the old influenza A subtype d. The 1968 Hong Kong pandemic killed 1 million people e. Antigenic drift is an accumulation of point mutations of viral genes encoding the viral neuraminidase and hemagglutinin
c. In an epidemic, a new influenza A subtype replaces the old influenza A subtype not necessarily; this describes the process of antigenic shift. Whilst antigenic shift often causes epidemics, it can also often give rise to pandemics due to a lack of seological cross-reactivity in humans for the new subtype. Epidemics can also be caused by an event of antigenic drift, with a virus of the same subtype, but no complete cross-reactivity for the new virus. a. true, lecture says 1-4days b. true, see https://en.wikipedia.org/wiki/Antigenic_shift. More commonly it is due to zoonosis d. estimates range from 1mil to 4mil e. true, due to reassortment and zoonosis
Which of the following is responsible for pandemic influenza? (reworded question) a. Over-vaccination and overuse of antiviral therapy b. Mutations in seasonal influenza c. Reassortment of avian, swine and human viruses d. The current influenza vaccine is only for two species of influenza A and one species of influenza C
c. Reassortment of avian, swine and human viruses d. there are currrently two vaccines, one quadrivalent (2 A, 2 B), one trivalent (2 A, 1 B). Influenza C is less pathogenic than B and so nto very significant
most common causes of pneumonia in infants 1-6 mo old
c. trachomatis
investigations for community acquired pneumonia
chest x-ray (most important), sputum gram-stain cultures, antibiotic sensitivities, blood culture, immunoassay for legionella. FBC, blood gas analysis (hypoxemia), inflamm markers
components of respiratory mucosa
ciliated columnar epithelium, ciliated columnar to simple squamous, mucous GOBLET CELLS, and glands containing both mucous and serous cells.
laryngeal orifice
communication between pharynx and respiratory tract
clara cells
detoxify harmful chemicals in air
superior meatus drains
drains posterior ethmoid sinus
what increases compliance?
emphysema, age
patients with absent spleen are at higher risk of which infections?
encapsulated bacteria and blood borne parasites
what week does the respiratory diverticulum appear
end of week 3
matrix protein
envelope protein that stabilizes the envelope and often plays a role in the assembly of progeny virions
nerve innervation of laryngeal muscles
external branch of the superior laryngeal nerve and the recurrent laryngeal nerve.
x-ray nosocomial pneumonia
fever, cyanosis, hypotension, and rapid cavitation of infiltrates (< 72 hours) on chest radiographs
what reduces lung compliance
fibrosis, absense of surfactant,
post-natal development
fluid in lung is rapidly absorbed --> mediated by glucocorticoids and hormones. - pulmonary vascular resistance falls. - increase in pulm blood flow - thinning of pulm arteries - blood fills alveolar capillaries - ribs need to lower and turn more oblique. Bbay ribs are horizontal and only allow for diaphragmatic breathing
radiology of atypical pneumonia
focal ground-glass opacity in a lobular distribution. Involvement is often diffuse and bilateral.
middle meatus
frontal, anterior ethmoid, and maxillary sinuses
enfurvitide
fusion inhibitor. binds gp41 and inhibits entry. reaction: dizziness, rash nausea, hypersensitivity
cd4 count 500-200
gingivitis, TB (can occur at any stage in countries with high TB rates, herpes zoster and simplex
what does env encode
gp120 and gp41
fetal hemoglobin
has a higher affinity for oxygen than adult hemoglobin. Allows for shift of O2 from maternal blood to baby
What happens if 2,3 BPG falls what effect will it have on blood transfusion in patient?
hemoglobin will less readily release oxygen to tissues. This is why we try to give patients fresh donations because 2.3 big will be higher
azygous lobe
right upper lobe expands. right posterior cardinal vein aberrantly migrates through the upper lobe of the right lung rather than over the apex. pleural layer is carried through the upper lobe creating an azygous fissure
derm findings of HIV
seroconversion rash (palmar), shingles, cold sores,
the ectoderm forms
skin and nervous system
HIV-1 structure
icosahedral with a conical capsid and a spiked envelope. - outer envelope containing gp120 proteins (env) - transmembrane containing gp14 proteins (env) - lipid bilayer - p17 (gag) - capsid made up of p24 protecting the viral RNA copies (gag) - reverse trasncriptase
difference in anatomical and physiological dead space in healthy vs lung disease?
in healthy patients these are v similar but in lung disease phys dead space may be much larger due to vent-perfusion mismatching
difference in HIV infection of macrophages vs CD4 T cells
in macrophages --> integration of viral DNA, used as messenger RNA to make viral RNA which is used to produce viral proteins. Viral proteins are assembled into complete virions and exit cell via exocytosis causing little damage to macrophage. OR it can live dormant within cellular dna. ENV gene that codes for gp120 will eventually undergo mutations causing it to change co-receptor affinity and bind to CXCR4. when these particles leave T cells they rupture and kill the cell.
babies of HIV mothers
initially falsely test positive
measurements made with spirometer
inspiratory reserve volume, tidal volume, expiratory reserve volume, but cannot measure residual volume.
pathology of atypical pneumonia
interstitial. inflammation predominately in the alveolar septa, mononuclear leucocyte infiltrate, intra-alveolar protein exudate, hyaline membrane formation
where is the pleura derived from?
lateral plate mesoderm
factors that affect airway resistance
length of the system, viscosity of air, diameter of airways
the endoderm forms
lining of gut and digestive system
bacterial pneumonia
lobar OR bronchopneumonic pattern, suppurative inflammation, and the stages: 1. congestion 2. red hepatisation, gray hepatisation, resolution
If shifted to the right affinity for oxygen is ______. This means that a ___ partial pressure is required to reach 50% saturation
lower. Higher
complications/prognosis of pneumonia
lung abscess, respiratory failure, sepsis, acute resp distress syndrome. promising in otherwise healthy patients. Patients older than 60 years or younger than 4 years of age have a relatively poorer prognosis than young adults. If pneumonia is left untreated, the overall mortality may become 30%.
HIV initially binds to which cell
macrophages. HIV membrane is studded with gp120 that binds to macrophages with CD4 receptors. - conformational change occurs that opens up cryptic face in gp120. - binding to CCR5 (inhibited by maraviroc). which changes conformation of gp41 to activate fusogenic apparatus of virus allowing for fusion to host membrane. - after years of producing viral DNA, gp120 changes allegiance to bind to CXCR4 on CD4 T cells.!
the mesoderm forms
muscle, bone, connective tissue, circulatory system, kidneys, gonads
atypical bacteria causes
mycoplasma pneumonia, legionella, coxiella burnetti
parts of nasal cavity
nasal vestibule, olfactory region, respiratory region
main regions of the nasal cavity
nasal vestibule: lined with skin bearing coarse hair, stratified squamous keratinized epithelium. olfactory region: limited to superior nasal concha, opposing septum, and intervening roof. Respond to odors as olfactory nerve. resp region: lined with pseudostratified columnar epithelium, goblet cells, serous, and mucous glands. warms and humidifies air. removes large debris
inferior meatus drains
nasolacrimal duct
why does acyclovir and cidofovir produce less side effects?
needs to be phosphorylated by virus encoded TK. this is only found in infected cells
accessory muscles of inspiration
sternocleidomastoid and scalene muscles. during for
function of protease inhibitors
stops cleavage of HIV polypeptide into functional parts, thus preventing maturation of new viruses. side effects: hyperglycemia, GI, lipodystrophy. - downregulates P450 enzymes
CAP causitive organisms
strep pneumonia, hemophillus influenza, moracella catarrhalis, staph aureus.
esophogeal atresia
no opening between esophagus and stomach
pulse oximetry
noninvasive method of measuring oxygen saturation by using a device that attaches to the fingertip. Continuous display. - useful in emergency dept, ICU, general anesthesia, during trasnport. - note: DOES NOT tell you oxygen rate or dissolved O2. - advantages: better than a clinician at detecting cyanosis. Reduces frequency of blood-gas analysis, reasonable for neonates. - confounding factors: non-functional Hb will give false readings, nail polish, tattoos, movement, poor lighting, low perfusion in peripheries
how does shunting present
normal PaC02 and elevated A-a gradient that does not correct with the administration of 100% oxygen.
how do you measure alveolar ventilation?
option 1: determine dead space. Subtract dead space ventilation from total vent (VA= VE-VD)
conducting zone is made up of
oral and nasal cavities, pharynx, larynx, and bronchial tree until terminal bronchioles
HIV opportunistic infections
oral candida, lymphadenopathy, epstein-barr virus, CMV, herpes zoster
antivirals for influenza A and B
oral oseltamivir phosphate
lobar emphysema
over-inflated lung, lower lobe collapse, left lung herniating across mediastinum
oxygen-Hb equilibrium curve
oxygen-Hb equilibrium curve. flat upper portion aids o2 loading at lungs and steep lower portion means O2 can easily diffuse into tissue (don't need to drop po2 very much to get oxygen to come off hemoglobin) SOOO lower the po2 the easier it is to release O2 from Hb
which protein does ELISA test look for in HIV patients
p24!
what makes up the floor of the nasal cavity
palatine and maxillary bones, as well as soft palate
3 common extracellular bacteria that cause pneumonia
strep pneumonia, staph aureus, H. influenzae, pseudomonas aerguinosa
Which bacteria most commonly causes pneumonia in COPD patients?
streptococcus pneumonia
alveolar pressure during tidal breathing
sub-atmospheric intra-alveolar pressure then draws air into the alveoli based on the pressure difference. Once the pressure equalized, a tidal volume of approximately 500 mL is delivered.
symptoms of community acquired CAP
symptoms: Fever, hypothermia, fatigue, tachypnea, hemoptysis, myalgias, headache, cough (with our without sputum), pleuritic chest pain. clinical findings: dullness to percussion, creptitations, bronchial breathing, pleural friction rub lab: neutrophil leucocytosis, hypoxemia, gram stain
HIV viral load over time
peaks around 3-4 wks, drops at 6th week and peaks closer to AIDS phase
what is the most common aids-defining illness in high income countries:
pneumocystis jiroveci. presentation: fever, increased resp rate, chest clear to auscultation, bilateral peri-hilar shadowing (enlargment of lymph nodes at the center of lungs). diagnosis: Use induced sputum to test w/ immunofloresence. ORGANISM NOT CULTURABLE.
pneumococcus causes
pneumonia, septicemia, sinusitis, meningitis. treatment --> injections of penicillin every 5 yrs.
paranasal sinuses layers
pseudostratified columnar epithelium. lamina propria: same as nasal cavity
structures found at root of lung
pulm artery and veins, bronchus, pulmonary ligament, groove for esophagus, pulmonary plexus
extracorporeal membrane oxygen in ARDS
pumps and oxygenates a patient's blood outside the body, allowing the heart and lungs to rest. used for children with ARDS
NNRTI side effect
rash, hepatotoxicity
pathological reason for fever
re-setting hypothalmic therpostat by IL-1, tnf-a
flow-mediated vasodilation
relaxation of a conduit artery when exposed to increased shear stress.
most likely outcome of typical bacterial pneumonia?
resolution
embryonic period
resp diverticulum arises as a ventral outopouching, undergoes 3 initial rounds of branching, 2 primary bronchial buds. 2-3 secondary bronchial buds (wk 5) 10 tertiary bronchi on each side (wk 6) become bronchopulmonary segments Concurrently stem of respiratory diverticulum forms trachea/larynx. Endoderm: Tubular ventral growth from foregut pharynx Mesoderm: mesenchyme of lung buds Intraembryonic coelom: Pleural cavities (elongated spaces containing pericardial and peritoneal spaces). - extra pulm artery --> lobular artery
gene therapy for immunodeficiency
restoring a functional copy of the defective gene into the affected patient's own hematopoietic stem cells (HSCs) by gene addition or gene editing
what does pol encode?
reverse transcriptase, integrase, protease
management of PID
treat infections immediately, - transfusion of hematopoetic stem cells to encourage T cell production and proliferation. - antibodies (IgG) can be pooled from donors. MHC complexes must match.
reaction of immune system to HIV
upon initial sensing of virus, mucosa signals to the epithelial cells to secrete MIP3. 1. infiltration of plasmacytoid dendritic cells and secretion of MIP1-B which recruits CD4 cells. 2. pro-inflamm cytokines and IFNs can arrest HIV infection but dendritic cells can take up virions and protect them in vesicles. 4. interferons stimulate the CD4 response with CCR54 receptors. 5. post-productive CD4 cells can escape and remain in transcriptional state to keep HIV silent. 6. HIV rapidly mutates faster than we can develop new antibodies with envelope hard to penetrate by antibodies.
explain mechanisms responsible for stimulation of ventilation with exercise
ventilation is increased by increased respiratory rate during moderate exercise. - Motor cortex sends impulses to exercising muscles, collateral impulses go to the resp centers in the brainstem. - The movement is detected by receptors in joints and muscles which stimulates an increase in ventilation - In prolonged exercise acidosis stimulates ventilation via carotid body receptors. What other cardioresp changes occur with exercise? Cardiac output rises, more capillaries open in muscles, distension of pulmonary capillaries, greater length of pulmonary capillaries used for gas exchange, less ventilation perfusion inequality, OEC shifts to right in exercising muscles and to the left at the lungs,
anatomical organization of pleura
viscera--> adheres to lung except hilum. parietal --> lines thoracic cavity, diaphragm, and mediastinal contents. Can be further divided into *costovertebral pleura *diaphragmatic pleura *mediastinal * cervical - pleural recesses --> spaces that lie at reflection of parietal pleura from costal surface.
when does seroconversion occur?
within 6-12 weeks of exposure
2,3-BPG
within erythrocytes, these babies allow increased oxygen delivery because of lower Hb affinity. 2,3 bis phos is produced from 1,3 bis phos by the enzyme bisphosphoglycerate mutase. This reaction consumes the energy that would have otherwise been used to make ATP
atypical pneumonia histology
•Tracheobronchitis •Attach to alveolar epithelial cells, kill them, inflamed alveolar septa •Alveolar septa - edema, hyperemia, lymphocytes, plasma cells •Alveolar cells - necrosis, inclusions, hyaline membranes. usually viral, decrease in surfactant due to type II pneumocyte damage. ** may not be responsive to oxygen treatment x-ray: diffuse, interstitial patten