Physiology Flashcards
Dopamine causes is shock
dopamine receptor mediated renal and mesenteric vascular dilatation and beta 1 receptor agonism at higher doses. This results in increased cardiac output. Since both heart rate and blood pressure are raised, there is less overall myocardial ischaemia.
Noradrenaline is
Noradrenaline is a catecholamine type agent and predominantly acts as an alpha receptor agonist and serves as a peripheral vasoconstrictor.
milrinone
Phosphodiesterase inhibitors such as milrinone act specifically on the cardiac phosphodiesterase and increase cardiac output.
Effects of receptor binding
α-1, α-2 vasoconstriction
β-1 increased cardiac contractility and HR
β-2 vasodilatation
D-1 renal and spleen vasodilatation
D-2 inhibits release of noradrenaline
majority of iron found in the body
70% of body iron is found bound to haemoglobin.
Iron Absorption
Duodenum and upper jejunum
Convergence of iron
Fe2+ (ferrous iron) much better absorbed than Fe3+ (ferric iron)
Ferrous iron is oxidized to form ferric iron, which is combined with apoferritin to form ferritin
tannin found in
tea
Decreased iron absorbtion by drugs
proton pump inhibitors, tetracycline
Iron Transport
In plasma as Fe3+ bound to transferrin
Second highest location of iron
Ferritin and haemosiderin 25%
From substrate (angiotensinogen)
Into product (angiotensin)
Surface of angiotensin
Liver
Effect of renin on angiotensinogen
Hydrolysis
posture stimulating renin
Erect
Drugs reducing renin secretion
beta-blockers, NSAIDs
Effect of Catecholamines on renin
Stimulates secretion
The cerebral perfusion pressure calculated by
CPP= Mean arterial pressure - Intra cranial pressure
What is Motilin
Motilin is released by the small bowel in response to alkaline contents in the duodenum/ jejunum and increases the migrating motor complexes in the small bowel
Which hormone induced satiety
CCK
Stimulating effect of Somatostatin
stimulates gastric mucous production
Somatostatin secreting cell
D
Mechanical effect of CCK
contraction of gallbladder and relaxation of sphincter of Oddi
Function of arachnoid granulation
filter, reabsorb, and drain CSF from the subarachnoid space into the venous system.
Ventricular function of first and second heart sounds
1st- isovolumic contraction
(No blood going out)
2nd- isovolumic relaxation
(No blood coming in)
Stages of ventricular filling
Rapid inflow
Diastasis
Atrial systole
The fourth heart sound
(S4) is an abnormal heart sound that can be heard immediately before S1 and indicates increased resistance to ventricular filling due to high atrial pressure or increased ventricular thickness. The presence of an S4 may indicate myocardial infarction—an almost universal finding during the early stages of acute myocardial infarction (if the patient has sinus rhythm). or shock.including high atrial pressure, increased ventricular thickness
mechanism fourth heart sound
caused by the vibrations created when the atria contract and fill the ventricle in late diastole.
(During stage of ventricular filling called ATRIAL SYSTOLE)
Relation of atrial waves with heart sounds
Just after 1st- c wave
Just after 2nd- v wave
what is incisura in aortic pressure curve
The incisura, also known as the dicrotic notch, is a downward notch in the aortic pressure curve that occurs between systole and diastole. It’s caused by a brief period of blood backflow before the aortic valve closes.
Monroe-Kelly Doctrine
considers skull as closed box, changes in pressure are offset by loss of CSF. When this is no longer possible ICP rises