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
