Physiology Flashcards
Which are the characteristics and murmurs in aortic stenosis and regurgitation?
- Aortic stenosis: Crescendo-decrescendo systolic ejection murmur (ejection click may be present)—-Syncope, Angina, and Dyspnea on exertion.
- **calcification in older patients (> 60 years old) or in younger patients with bicuspid aortic valve.
- Aortic regurgitation: diastolic decrescendo murmur— hyperdynamic pulse, and head bobbing when severe and chronic.
- ** Often due to aortic root dilation, bicuspid aortic valve, endocarditis, rheumatic fever.
What is the colipase?
is a proteic cofactor necessary to pancreatic lipase activity
A patient that has a lung region that is underventilated but well perfused, is similar to what kind of shunt?
Physiologic shunt different to physyologic dead space—- not blood flow yes ventilated
Which is the compound that serves as a precursor of uroporphyrin? and which are the enzymes that result damaged in porphyria?
is succinyl coA + Glycin——– amilovulinic acid
1. Acute intermittent porphyria—– Porphobilinogen
deaminase
2. porphyria cutanea tarda—-Uroporphyrinogen
decarboxylase
Which symptoms and signs could you suspect a methanol poisoning? and which is the enzyme that metabolized it?
Exposure to paint thinner + ophtalmologic and neurologic symptoms + anion gap metabolic acidosis
—it is metabolized by formaldehyde dehydrogenase
Where it derives Von willebrand factor ?
- from weibel palade bodies in endothelial cells
- alpha granules of platelets
Thrombotic thrombocytopenic purpura is due to?
decreased ADAMTS13 (enzyme that normally cleaves vWf multimers into monomer for eventual degradation)—–causes abnormal platelet adhesion (microthrombi)
which are the substances are required to coagulation factors for activation?
- exposure to an activating substances: tissue thromboplastin activates factor VII (extrinsic pathway)
subendothelial collagen activates fractor XII (intrinsic) - phospholipid surface of platelets
- calcium (derived from platelets dense granules)
Released Ca2+ in cytoplasm of muscle cell leading to
Binds to troponin C, causing a conformational change that moves —-tropomyosin out of the myosin-binding groove on actin filaments = contraction.
Is ejection fraction equal to
- stroke volume/ end diastolic volumen
- SV= end distolic volumen - end systolic volume
Lung recoil vs lung compliance
Lung recoil— rebound of the lungs after having been stetched by inhalation
Lung compliance— ability to stetch and expand
GFR autoregulation
decrease of GRF — leading to decrease the sodium to be sensed by macula densa in distal tubule—afferent arteriolar dilation and constriction of efferent arteriolar due to RAS activation.
The increase in systemic vascular resistance and decrease in venous capacitance are due to sympathetic stimulation of…
vascular sympathetic alpha 1 receptor: inadequate compensatory stimulation—- is the major cause of orthostatic hypotension.
- Stroke volume
- changes in exercise
end dyatolic volume- end systolic volume
*In exercise EDV (preload) incresed trying to increase stretch in myocytes leading to increased contractility
and ESV decreased because peripheral vascular resistance (afterload decrease) because vasodiltation of muscles leading to heart emptying quickly
Incretins
GI hormones produced by gut mucosa —- stimulate pancreatic insulin secretion (in response to sugar cotaining meals). Independent of glucose blood level
- Glucagon like peptide 1 (GLP-1)
- Gastric inhibitory peptide
elastase
- Protease
- Contained in alveolar macrophages lysosomes and azyrophilic granules of neutrophils.
Hyperventilation
Decrease PCO2— respiratory alkalosis
secondary to hypoxia for example
Vomiting reflex
the postrema area in the IV ventricle —– has a chemorecpetor trigger zone— respond to neurotransmitters, drugs and toxins.
the nucleus tractus solitarius (NTS) in medulla (receives information of area postrema, GI tract through vagus nerve, vestibular system and CNS.
Neurons of NTS projects to medulla nuclei and coordinate vomiting process
Five major receptors in vomiting
- serotonin 5HT3
- Neurokinin (NK1)
- Histamine H1
- Dopaminegic D2
- Muscarinic M1
Minimal alveolar concentration MAC
Is the % of anesthesic in inspired gas to produce 50% of patients unresponsive to painful stimuli.
Potency is inversely related to MAC
What happened with in HPO4 in diabetic ketoacidosis?
HPo4 acts as buffer, Binds with H to form H2PO4— excreted in urine (increased)
Sarcomere
overlapping filaments of myosin and actin
Single sarcomere is the distance between two Z lines
Which is the reason for loss bone mass in menopausal women?
low estrogen level—– increased production of inflammatory cytokines (IL-1 and TNF Alpha) —–increased expression of the receptor activator of Nf-Kappa Beta ligand (RANK-L)—– increasing osteoclast activity
Micturation reflex
- Sacral micturation center: S2-S4—- responsible of bladder contraction
- Pontine micturation center: in pontine reticular formatio, relaxation of externar urethral esphincter
- Cerebral cortex: inhibits sacral micturation center
Action potential of pacemaker
phase 0, upstroke: opening calcium channels (L- channels)
phase 3, repolarization: begin with closure of L type calcium channels, opening K channels, efflux potassium
phase 4: slow influx of sodium
Which are the three major components of RAA system regulation?
- macula densa (distal tubule sodium sensor)
- Intrarenal baroreceptors
- beta adrenergic receptors
Romberg test
is a propioception test—- ATAXIA
Difference between cerebellar and sensory:
- sensory: with eyes closed the patienet lost equilibrium (damaged is in posterior columns or peropheral nerves)—- tabes dorsalis or vit b12 deficiency
Normal left atrial pressure?
10 mmhg
Which are the main muscle fiber types in the body?
Type I: Slow twitch — postural maintenance, aerobic metabolism
Type II: fast twitch, rapid forceful pulses of movements, anaerobic metabolism.
Insulin receptor
- Tetramer: 2 alpha subunit, 2 beta
- Alpha extrecellular: bind to insulin
- Beta: intracellular, contain tyrosine kinase domain
- when insuline attaches—- autophosphorylation of insulin receptor ————— translocation of GLUT-4 to cell membrane.
- TNF- Alpha—————— induces insuline resistance– activation serine kinases that inhibits tyrosine phosphorylation.
Pulmonary capillary wedge pressure
almost equal to left atrial pressure and left ventricular end diatolic pressure.
** Normally are equal in diastole but in mitral stenosis the left atrial pressure increase
Alveolar hyperventilation
low pco2
persistent Hypoxemia
Acute onset Dyspnea
Central and peripheral chemoreceptor
- central: most stimulated by PCO2
- peripheral: by po2
- COPD patients have decreased sensitivity to changes in PCO2, detects only changes in PO2 (peripheral chemoreceptors)
wich Pulmonary artery catheterization measured?
pulmonary artery occlusion pressure (the catheter is inflated in pulmonary artery) — reflects left atrium and left ventricular end diastolic pressure
In which pulmonar volume the pulmonar vascular resistance is lowest?
at functional residual capacity————- PVR takes the shape of “u”———- alveolar and extraalveolar resistance are increased at high and low volumes (max inspiration and max expiration)
Respiratory work in restrictive and obstructive disease
- Restrictive: deep and rapid respiratory frequency = decreased respiratory woek
- Obstructive: slow and deep breaths—- minimized respiratory work
Diffusing capacity for carbon monoxide
- obstructive: asthma (normal), emphysema (decreased)
- restructive: instrinsic (decreased), extrinsic (normal)
Pancreatic exocrine secretions
Na and K are constant: as plasma concentrations
HCO3 and Cl varies with pancreatic fluid rate, increases in reponse to secretin
Metabolic changes in diabetic ketoacidosis
hyperk: because acidemia drives cells H/K exchange
hypoNa: osmotic activity of glucosa, (serum sodium drops 1.6 meq for every 100 mg rise of blood glucose)
I band and H band
I Band: thin (actin) filaments, contain Z lines—- lengthens during muscle relaxarion and shortens during contraction.
H band: inverse I band, thick (miosin fibers) both relaxes as the same time
Which is the reason to myocyte hypertrophy in myocardial infarction?
Decrease aerobic metabolism
Na/K ATPase pump and sarcoplasmic reticulum Ca ATPase——–doesn´t work well———acummulation of sodium and calcium intracellular————- attract free water and cause cellular an mitochondrial swelling
Which of the nephron segments responds to vasopressin by increasin absorption of a specific solute?
medullary segment of collecting duct
urea concentration increases
why is the reason of a rise in glomerular filtration rate during pregnancy?
a rise of plasma volume
increased renal circulation mediated by hormone relaxin, stimulated by Bhcg
Dimished bladder capacity because fetus (increased intraabdominal pressure)
Pregnancy hormones increase urethral tone and relax pelvis muscle floor = stress incontinence
First objective sign of puberty
Breast bud development
Most important factor involved in coronary blood flow autoregulation
Adenosine and nitric oxide (acst via guanylate cyclase enzyme— increase production of cGMP —- causing smooth muscle relaxation)
Secretin
release from duodenum in response to cid and fat—- incresing pancreatinc HCO3 secretion and inhibits release of gastrin.
Paradoxically stimulates gstrin release in gastrinomas
Diastolic heart failure
normal left ventricular ejection fraction > 50%
Normal end diastolic volume
Increased left ventricular filling pressures
which is the position of vocal cords while cough
open
CFTR mutantt channel in cystic fibrosis encodes which kind of gate?
ATP gated Cl - channel
Hepcidin
acute phase reactant, synthesized in lover
- central regulator homeostasis of iron
- Influenced iron storage
- inhiboting ferroportin (protein that tranfering intracellular iron into circulation)
