Flashcards in HIGHEST YIELD PHYSIO Deck (71)
What'is/are'the'BEST' index/indices'of'left' ventricular'pre-load?'
- The best indices of left ventricular preload are ventricular EDV and EDP.
- Less reliable indices include left atrial pressure, pulmonary venous pressure, pulmonary wedge pressure.
Premature'ventricular' contractions'(PVCs)' causes'the'following'ECG' changes,'
C.'T wave'inversion' immediately'after'a' premature'beat'
The basic rhythm of respiration
is generated mainly in the dorsal respiratory group of neurons.
The neurons of the ventral respiratory group remain almost totally inactive during normal quiet respiration. Therefore, normal quiet breathing is caused only by repetitive inspiratory signals from the dorsal respiratory group transmitted mainly to the diaphragm, and expiration results from elastic recoil of the lungs and thoracic cage.
They are especially important in providing the powerful expiratory signals to the abdominal muscles during very heavy expiration.
The function of the pneumotaxic center
is primarily to limit inspiration.
A'normal'25 year'old' man'has'a'respiratory' rate'of'14'breaths'per' minute.''What'is'his' alveolar'ventilation?'
Computation is 500ml (normal tidal volume) – 150ml (normal anatomic dead space, assuming that this subject has 0 physiologic dead space) = 350ml x 14 = 4,900 ml, rounded off to 5L.
Voltage-gated Na channels are opened during depolarization. Na- K ATPase pump is the one pumping 3 Na out and 2 K in. There is virtually minimal/negligible conductance of sodium in a resting membrane.
They'are'virtually' closed'when'the'cell'is'at' rest.'
The'triggering' mechanism'for'the' genesis'of'REM'sleep' depends'on'neurons'that' release:'
Acetylcholine is released in high levels as a result of wakefulness and alertness, but it is also found in high levels during REM sleep. Its lowest levels have been found in slow wave sleep when there is no cortical arousal, but relaxation.
The release of certain neurotransmitters, the monoamines(norepinephrine, serotonin and histamine), is completely shut down during REM
which is a result of increased growth hormone release from the ANTERIOR PITUITARY GLAND after the epiphyseal plates have already closed. In over 90 percent of acromegaly patients, the overproduction of growth hormones is caused by a benign tumor of the pituitary gland, called an adenoma.
permits more time for ventricular filling, hence better filling of the ventricle.
Prolonging the diastole will result in decreased heart rate and increased stroke volume.
Duration of diastole has no effect on peripheral resistance.
The'sympathetic'nervous' system'modulates'the' output'of'the'pacemaker' cells'of'the'heart'by:'
Sympathetic activation, which releases norepinephrine (NE), increases pacemaker rate by decreasing gK+ and increasing slow inward gCa++ and gNa+; the pacemaker current (If) is enhanced. These changes increase the slope of PHASE 4 so that the pacemaker potential more rapidly reaches the threshold for action potential generation.
The principal means by which acclimatization comes about are (1) a great increase in pulmonary ventilation,
(2) increased numbers of red blood cells,
(3) increased diffusing capacity of the lungs,
(4) increased vascularity of the peripheral tissues, and
(5) increased ability of the tissue cells to use oxygen despite low PO2.
In'the'sarcomere,'which' of'the'following'keep/s' the'myosin'and'actin'in' place?'
The side-by-side relationship between the myosin and actin filaments is difficult to maintain. This is achieved by a large number of filamentous molecules of a protein called TITIN
This is manifested by abnormally elevated levels of cortisol.
A'newborn'male'was'held' at'the'NICU'because'he' did'not'pass'out' meconium'after'48'hours' of'life.''Plain'abdominal' radiographs'showed' distended'bowel'loops' with'a'paucity'of'air'in' the'rectum.''Absence'of' which'of'the'following' is/are'expected'to'be' seen'in'the'biopsy'of'the' affected'segment?'
Both the myenteric (Auerbach) plexus and the submucosal (Meissner) plexus are absent from the muscular layer of the bowel wall in
The'concentrating' mechanism'of'the' nephron'depends'upon' the'maintenance'of'a' gradient'of'increasing' osmolality'along'the' medullary'pyramids.'
This gradient is produced by the operation of the loops of Henle as countercurrent multipliers and maintained by the operation of the vasa recta as countercurrent exchangers.
are strongest in the 3rd- 4th day.
All'of'the'following'lung' volume'and'lung' capacities'cannot'be' measured'clinically' except?'
All'of'the'following'are' muscles'for'inspiration' except?'
are SLOWEST in the STOMACH and FASTEST in the SMALL INTESTINE
10, 000 feet:
most impt effect is Decreased mental proficiency
All'of'the'following'are' characteristics'of' isovolumetric'ventricular' contraction'phase'of'the' cardiac'cycle
EXCEPT END SYSTOLIC VOLUME
A.''''It'is'a'period'between' closure'of'the'AV'valves' and'opening'of'Semilunar' valves'
B.'''''There'is'an'abrupt' increase'in'the' ventricular'pressure' more'than'the'atrial' pressure' C.'''''All'valves'are'closed' in'this'phase' D.'''''In'this'phase,'the'1st' heart'sound'is'produced'
E. End diastolic volume
rapid'filling' phase'(flow'of'blood'from' atria'to'ventricle)'
Phase 4- slow DEPOLARIZATION conduction, inward Na current
is responsible for SA nodal automaticity
Bradykinin and histamine