Physiology Flashcards
U waves in EKG are seen in:
Hypokalemia
Bradycardia
First cardiac sound is due to:
Mitral and tricuspid valve closure
Second cardiac sound is due to:
Aortic and pulmonary valve closure
S3 (gallop) is due to and can be associated with:
Fast ventricular filling or filling an already full ventricle
In eccentric hypertrophy (dilation)
Congestive heart failure and mitral regurgitation
S4 is due to and can be associated with:
Atrial kick
Indicates an stiff ventricle
In concentric hypertrophy
Hypertension and aortic stenosis, hypertrophic cardiomyopathy
Component of the jugular venous pulse absent in tricuspid regurgitation:
X descent (atrial relaXation) Absent in tricuspid regurgitation
Holosystolic high-pitched blowing murmur indicates:
Mitral/tricuspid regurgitation
Crescendo-decrescendo systolic murmur indicates:
And other characteristics associated with this murmur:
Aortic stenosis
Associated also with pulsus parvus et tardus
Holosystolic harsh-sounding murmur indicates:
Ventricular septal defect
Late systolic crescendo murmur with midsystolic click indicates:
Mitral valve prolapse
That it’s the most frequent valvular lesion
High-pitched blowing early diastolic decrescendo murmur indicates:
And other characteristics associated with this murmur:
Aortic regurgitation
Associated also with bounding pulses and head bobbing
Delayed rumbling late diastolic murmur indicates:
And other characteristics associated with this murmur:
Mitral stenosis
It follows opening snap
Continuous machine-like murmur indicates:
Patent ductus arteriosus
Heart rate is determined by which component of the pacemaker action potential?
By the slope of phase 4 in the SA node
Which infection can result in a 3rd-degree heart block?
Lyme disease
Which heart block can Lyme disease lead to?
3rd-degree heart block
Intrapleural pressure at FRC:
Negative, small change ~-5cm H2O
Chromaffin cells in adrenal medulla are stimulated by and secrete:
Stimulated by Ach released by sympathetic preganglionic neurons
Segregate epinephrine and norepinephrine
Preload is approximated and decreased by:
End-diastolic vol.
vEnodilators
Afterload is approximated and decreased by:
Mean arterial pressure
vAsodilators
Ach is released on the synapses at:
Neuromuscular junction
Both sympathetic and parasympathetic ganglia
Postganglionic parasympathetic organ target
NE is released on the synapses at:
Postganglionic sympathetic organ target (the adrenal acts as the sympathetic ganglia)
G protein, hormones that bind to it and second messenger of beta receptors:
Gs prot (where epi, glucagon, TSH and PTH bind) Activates adenyl cyclase to increase cAMP
G protein and second messenger of alpha 1 receptors:
Gq prot
Activates phospholipase C that generates IP3 and DAG
G protein and second messenger of alpha 2 receptors:
Gi prot
Inhibits adenyl cyclase to decrease cAMP
Characteristics of the holosystolic murmur in mitral regurgitation:
Best heard at apex and left lateral decubitus
Radiates to the axila
Increases with hand grip and squatting
Characteristics of the holosystolic murmur in tricuspid regurgitation:
Best heard at the left 2 and 3 intercostal spaces
Increases with inspiration
Characteristics of the holosystolic murmur in ventricular septal defect:
Best heard at the left 3 and 4 intercostal spaces
Harsh, loud and accompanied by a thrill
Increases with hand grip
Which receptors are regulated by cortisol?
Cortisol upregulates α1 receptors of epinephrine (in blood vessels)
Also inhaled corticoids upregulate β2 receptors in bronchial smooth m. increasing responsiveness to albuterol. Also up regulates β receptors in the liver
Adequate cortisol levels allow glucagon to work releasing glucose
(Thyroid hormone upregulates beta 1 receptors of epinephrine (on the heart))
Which receptors are regulated by thyroid hormone?
Thyroid hormone upregulates beta 1 receptors of epinephrine (on the heart)
What accentuates the splitting of S2 in inspiration?
Conditions that delay RV emptying (pulmonic component) as pulmonary stenosis and right bundle block
Because inspiration delays the pulmonic component of S2
What causes a wide and fixed splitting of S2:
ASD
Accompanied with a mid-systolic ejection murmur on the pulmonic area (left upper) because causes RV overload! The murmur is systolic!
What is the paradoxic splitting of S2 and what causes it?
Splitting of S2 on expiration
Caused by conditions that make the aortic valve close very late as advanced aortic stenosis and left bundle block
Where in the airway is the biggest resistance and why?
In the SEGMENTAL bronchi, first and second divisions
due to turbulent flow
Segmental bronchi → Subsegmental bronchi → Terminal bronchioli* → Respiratory bronchioli
* Terminal bronchioles are the ones inflamed in asthma
Hyperkalemia consequences:
Cell depolarization (chronic weakness and fatigue) High T waves (V. fib) Acidosis
Hypokalemia consequences:
Cell hyperpolarization (weakness and fatigue) Long QT (Torsades) and U waves Decreased insulin secretion
Stimuli that increase vasopressin-ADH:
High osmolality: osmolality activates hypothalamic osmorreceptors
Low BP: low baroreceptor stretch activates the sympathetic but also ADH secretion
Stress: CRH and AT2 can increase ADH
Stimuli that increase aldosterone:
High ATII
High K
ACTH does not control aldo!
Stimuli that increase renin:
Low perfusion pressure to the kidney (~low BP)
Low Na to the macula densa*
High sympathetics to the kidney
*Low Na to the macula densa causes no Na to go into the macula densa trough Na/K/2C so no depolarization and no Ca influx which actually activates the Ca inhibited adenylate cyclase and increases renin release
Alpha 1 effects:
VasoCONSTRICTION
Smooth m. CONTRACTION (bladder sphincter, GU, pupillary dilator)
Alpha 2 effects:
Decrease sympathetic activation at the CNS
Inhibits insulin release and lipolysis
Decreases aqueous humor
Increases platelet aggregation
Beta 1 effects:
Heart: increase HR and contractility
Increase renin release in juxtaglomerular cells
Beta 2 effects:
Lungs: bronchodilation
Vessels: vasoDILATION
General smooth m. RELAXATION: uterus relaxation
Increases insulin (and K cellular uptake) release and lipolysis but alpha 2 effect is predominant
Decrease glucogenolysis (this is how β blockers cause hypoglycemia)
Increases aqueous humor
Bone remodeling indicators:
High serum osteocalcin and alkaline phosphatase
High urinary excretion of hydroxyproline
Which drug causes nephrogenic diabetes insipidus?
Lithium
LH acts on which cells:
Leydig cells in males and theca cells in females
FSH acts on which cells:
Sertoli cells in males and granulosa cells in females
Hormones inhibited by somatostatin (octreotide):
Insulin Glucagon Gastrin VIP CCK GH TSH!!!
Somatostatin has 3 min half life but octreotide 90 min
Function of Apo B-48:
Transport chylomicrons out of the cell into the lymphatics
Function of Apo C-II:
Activates lipoprotein lipase that breaks down TG in the chylomicrons into FA so they go into the adipocyte
Function of Apo E:
For rEcycling chylomicron rEmnants and LDL
Which hypothalamic nucleus mediates satiation?
The ventromedial nucleus
Which hypothalamic nucleus mediates hunger?
The lateral nucleus
Key changes in neurogenic shock:
Vasodilation and no sympathetic activation
Key changes in septic shock:
Vasodilation and sympathetic activation (increase HR and contractility)
Key changes in hypovolemic shock:
Loss of fluid and vasoconstriction
Key changes in cardiogenic shock:
Left ventricular failure and vasoconstriction
What is the vital capacity?
Everything but the residual vol.
Which thyroid parameters increase in pregnancy?
You have more binding proteins! (even if you have less albumin causing edema)
T3 resin uptake is low
Just the TOTAL T3 and T4
The free ones and TSH are normal
Where do the curves for lung collapse tendency and chest expansion tendency meet?
At the functional residual capacity (increases in emphysema and decreases in fibrosis)
Hormones that bind intracellular receptors:
Cortisol Estrogens Progesterone Testosterone Vit D Aldosterone Thyroid hormone
Which 3 molecules can increase acid production by parietal cells?
Ach: blocks H/K and ↑ Gastrin
Gastrin: blocks H/K and ↑ His
Histamine: blocks H/K
But in general all 3 act synergistically so inhibiting one will decrease the effect of all of them. Omeprazol blocks all!
Hormones secreted by the posterior pituitary:
ADH
Oxytocin
The smooth endoplasmic reticulum is needed to and in which cells is big:
Make steroid hormones (androgens, estrogens, corticoids and aldo) and lipoproteins
Detoxify
Glycogen degradation and gluconeogenesis
Liver, adrenal cortex and gonads have big SER
The rough endoplasmic reticulum is needed to and in which cells is big:
Make secreted substances as peptide hormones (ADH, insulin, gastrin, PRL…)
Make lysosomal enzymes
Make membrane proteins
They are marked with the N-terminal hydrophobic sequence so they are recognized by SRP
Globet and plasma cells have big RER
What does extracellular Ca2+ to the fast Na+ ch?
High extracellular Ca2+ blocks fast Na+ ch
What K channel is deficient in congenital long QT segment? Where is the gene? What syndromes are generated?
Delayed rectifier (one open in phase 2 and 3) D3!
Chromosome 11
AR: Jervell Lange-Nielsen ❤️👂
AD: Romano-Ward ❤️
(also Na ch that take longer to close after action potential)
Do not give 1A and 3 antiarrhythmics! Give Mg if they get torsades
What is RANK-L’s function?
Differentiates osteoclasts, promotes bone break down
What is OPG’s (osteoprotegerin) function?
Prevents RANK-L to bind and activate osteoclasts
So decreases bone break down
What activates PTH and what are it’s functions?
Low Ca activates PTH and PTH increases Ca
By:
Activating Vit D
Decreasing renal Ca waste (and wasting K)
Breaking down bone (activates osteoblasts that activate osteoclasts in a paracrine way)
What activates calcitonin and what are it’s functions?
High Ca activates calcitonin and calcitonin stops bone break down
What activates Vit D and what are it’s functions?
Low Ca activates PTH and PTH activates Vit D, Vit increases Ca and bone
By:
Increasing Ca and P GI absorption (calbindin)
Enhancing PTH action on distal tubule
Manuvers that decrease the murmur in HOCM:
Manouvers that increase preload and/or afterload:
Passive leg raise
Hand gripping
Squatting
It is decreased by strain Valsalva
Changes in prerenal, renal and postrenal acute renal failure:
Pre: low FeNa high BUN
Renal: high FeNa low BUN
Postrenal:
early: low FeNa high BUN
late: high FeNa low BUN
Type of hypoxemia that cannot be corrected by 100% oxigen:
Right to left shunt!
Low PaO2, PARTIAL PRESSURE! that cannot be corrected
Pressure readings in RV, pulmonary artery and Wedge pressure:
RV: 0-25
Pulmonary A: 10-25
Wedge pressure: 5-10
Muscle spindles trigger, reflex involved and innervation:
Respond to muscle stretch: involved in myotactic reflex (patellar…)
Innervated by type 1a (and 2 neurons)
Golgi tendon organ trigger, reflex involved and innervation:
Respond to muscle force: involved in inverse stretch reflex in which muscle contraction is stopped during excessive stretch (too much weight)
Innervated by type 1b
Causes of metabolic acidosis with high anion gap:
MUD PILES
Methanol 👁: antidote is fomepizole/ethanol UREMIA! Diabetic ketoacidosis Paracetamol Iron!!! Isoniazid Lactic acidosis Ethylene glycol (antifreeze) nephrotoxic and oxalate crystals: antidote is fomepizole/ethanol Salycates
- Propylene glycol (antifreeze) also causes an anion gap metabolic acidosis and does not cause 👁 or kidney symptoms just seizure and coma
- Isopropil alcohol (rubbing alcohol) does NOT cause an anion gap metabolic acidosis just coma
If no anion gap think about, bicarb loss: diarrhea, fistula, renal tubular acidosis (acetazolamide, spironolactone, addison), massive IV saline infusion that ↑ Cl, ingestion of HCl
What do you measure to diagnose 21–beta hydroxylase deficiency?
17-Hydroxyprogesterone
The Golgi apparatus is needed for which two functions?
Distribution
Post-transcriptional modification (for example phosphorylation of mannoses in lysosomal enzymes by phosphotransferase so they can enter the lysosomes)
N-glycosylation: what is it? Where? and what for?
Addition of sugars to asparagine
Stars in the ER can be modified in the Golgi for example by phosphorylation of mannoses in the N-linked sugars
Modify prot as for target them into heading to lysosomoes
O-glycosylation: what is it? Where? and what for?
Addition of sugars to serine and threonine
In the Golgi
Modify prot as for AOB blood groups
Thyroid panel in thyrotoxicosis facticia:
↓ TSH and ↓ RAIU (radioactive iodine uptake) ↓ thyroglobulin (T4 precursor)
If patient is taking:
T3 (triiodohyrosine): ↑ T3 (triiodohyrosine) only
T4 (thyroxine/levothyroxine): ↑ T4 and T3 (because T3 comes from T4 breakdown)
Respiratory changes with age:
Lung compliance increases (recoil loss=elastance loss)
Chest wall compliance decreases (stiff)
Chest wall becomes stiff and lungs fluffy
Residual vol increases
Other more predictable:
Increase: A-a gradient, V/Q mismatch
Decrease: FVC, FEV1, strength, cough, arterial PO2, ventilatory response to hypoxia and hypercapnia
Sertoli cells functions:
Secrete inhibin B to inhibit FSH Secrete androgen-biding protein Convert testosterone to androstenedione Secrete MIF Support and blood testes barrier!!! Temperature sensitive
Physiologic changes when you get into the water:
Blood vol increases
ANP increases
ADH decreases: pee