Physiology Flashcards
Which nerve supplies parasympathetic supply to the heart?
Vagus nerve
Which nerve supplies sympathetic supply to the heart?
Thoracic spinal nerve
Which skeletal muscle has the lowest membrane potential?
Autorhythmic Myocardium - 60mV
P-R indicates atrial _________
Activation
Do Juxataglomerular nephrons or Cortical nephrons have longer loops?
Juxtaglomerular nephrons ! they have Vasa Recta
Cortical nephrons have shorter loops.
Movement of particles between the the glomerular membrane is due to _____and _____ pressures
Hydrostatic and Osmolar pressures.
Does afferent or efferent tubules in the kidney have greater effect in controlling Pressure Natreusis?
Afferent - because if efferent is too constricted than it can actually act to increase the colloid pressure even more and hence decrease NFP.
Proximal tubule absorbs how much sodium and water?
65% sodium + 65% water
____________ is impermeable to H20 and hence only absorbs 25% of sodium. This in turn makes the urine more dilute and allows water to be absorbed in the next part.
Ascending loop of Henle
The descending loop absorbs 10% water.
Aldosterone and ADH act at which part of Renal tubes?
Distal convulated
Macula densa is found where?
What ion does it look at to regulate increase Renin and Angiotensin release?
Macula densa is found in the JGA
It looks at Sodium concentration. if low sodium it releases more Renin and hence Aldosterone to increase sodium and water absorption.
Osmoceptors are very respondent to ________ and slightly respondent to _____. They are found in paraventricular nucleus and transfer ____ to the pituitary.
very respondent to Osmolality and slightly respondent to BP (Big change needed)
Release ADH (vasopressin)
Aldosterone is released by the adrenal cortical glomreulosa cells. It is released in response to:
1.
2.
- Increased k+ ion
2. Angiotensin II
Where are Baroceptors found?
Aortic arch and Carotid artery
Where are Stretch receptors found?
Atrium, Ventricle and Pulmonary vesicle
________is produced by the Liver. Renin acts to convert it to ________. ACE in the _____ converts it then to Angiotensin II which acts on various sites.
Angiotensinogen is produced by the Liver. Renin acts to convert it to Angiotensin I. ACE in the lungs converts it then to Angiotensin II which acts on various sites.
Angiotensin acts on Efferent arterioles or Afferent arterioles?
Efferent - leads to their vasoconstriction. Hence increase urine
Renin is released in response to three things. Which of the following three out of four?
- Renal Baroceptors - low BP –> more Renin
- Potassium concentations –> more postassium –> more renin
- Increased sympathetic nerves
- Macula Densa Cells
- Renal Baroceptors - low BP –> more Renin
- Increased sympathetic nerves –> leads to decreased Renin
- Macula Densa Cells
What acts to increase permeability of aquopores on the luminal surface?
ADH
Alpha intercalated cells secrete acid or base into urine?
Acid! A for A
Na+- H+ exhanger are found where? (3)
PCT, Ascending loop and DCT
Volume depletion leads to acidosis or alkalosis?
Alakalosis - body tries to retain Na+ and hence H+ is lost and HCO3- is also retained.
Increased PCO2 leads to alkalosis or acidosis?
Acidosis in acute - due to buffering system making H+.
Increased Aldosterone production leads to acidosis or alkalosis?
Metabolic alkalosis. HCO3- is reabsorbed with Na+
Hypokalaemia leads to acidosis or alkalosis?
Alkalosis. To increase K+ reabsorption , HCO3- is also reabsorbed.
Osmotic diuretics like mannitol act where?
Descending loop of henle
Loop diuretics like Frusemide act where?
Ascending limb of henle. Prevent Sodium absorption?
Thiazides and potassium sparing diuretics act where?
DCT
ADH acts where?
Collecting tubules?
Thiazide act on which channel?
Na+- Cl- Channels at the DCT
Frusemide acts on which channel?
Na+,K+, 2Cl- Channel at Ascending loop. hence prevents reabsorption of Na+ and K+
Myocardial cells have a longer action potential due to ___ entry
Ca2+ entry - it creates the plateau
Stroke volume =
End diastolic volume - end systolic volume
Frank Starling Mechanism (law of the heart):
When more blood flows through the heart, the ventricular walls stretch and the force of cardiac contraction increases
MAP =
CO x TPR
The __________ are the ain mechanism that maintains mean arterial pressure in response to orthostatic stress and the mild haemorrhage
Baroreceptors
