Homeostasis + Osmosis Flashcards
The homestatic feedback loop components exhibit which of the following sequence following a stimulus?
Sensor (or receptor) - Comparator / Controller - Target organ (effector) - Response
Which of the following combinations of main systems contribute the most to homeostasis?
Endocrine + Nervous Systems
Which of the following statements regarding the body fluid volume in a 70kg male adult is FALSE?
Plasma volume = 16 litres
Which of the following BEST describes Homeostasis?
To maintain a NEAR- constant Internal environment.
Why do Positive Feedback systems that are part of a normal physiological response include some mechanism that TERMINATES the system?
Without that thing to stop the system, it would just keep going, getting stronger + stronger!
E.g childbirth - contractions are NOT needed once baby is born!
What would happen to Heart Rate if some stimulus caused blood pressure to DECREASE?
Would this occur by positive or negative feedback?
If blood pressure dropped, heart rate would increase. (As blood flowing faster will cause more pressure!)
Vasoconstriction would happen also.
Negative feedback - once heart rate is up it would need to be controlled so it doesn’t get too high!
If a sample of red blood cells were placed in a solution with Osmolality of 390 mOsm / Kg H20 would they shrink, swell or stay the same size?
HIGHER value than we would expect for cell plasma = solution is Hypertonic.
As the cell has got hardly any particles in it, there is a HIGH concentration of water. Outside theres loads of particles, so relative concen of water is LOWER.
Therefore, water will move from high to low concen and will move to OUTSIDE the cell and the cell will SHRINK!
