L1_Homeostasis Flashcards
(27 cards)
What is the concept of Physiological Homeostasis
(A1_1): Maintain constant internal environment in face of external factors/changes
Where is the most sodium of the body contained?
(A1_2): Sodium (Na) is within Extracellular Fluid Volume (EFV)
Where is the most potassium of the body contained?
(A1_2): Potassium (K) is within Intracellular Fluid Volume (IFV)
Where is MOST of the Body Water Contained?
(A1_3): MOST of the body water is contained within the LEAN BODY MASS
How would a male person of 80kg with a body water content of 48 liters be categorized?
(A1_4): The Fat would be in the NORMAL range (18%)
What percentage of total body weight is Total Body Water?
(A1): TBW = 57% total body wieght
What percentage of total body weight is Lean Body Mass (LBM)?x
(A1):LBM = 79% total
What percentage of Total Body Water (TBW) is Extracellular Fluid Volume?
(A1): Extracellular = 37% TBWx
What percentage of Total Body Water (TBW) is Intracellular Fluid Volume?
(A1): Intracellular = 63% TBW
Are Plasma Volume and Interstitial Volume Contained within Extracelluar or Intracelluar Fluid Volume and what is the percentage of total body water of each?
(A1): Plasma Volume and Interstitial Volume are contained within Extracellular. Plasma = 9% TBW, Interstitial Fluid = 28% TBW
Four grams of a dye are administered into a subject weighing 80 kg and having a lean body mass of 64 Kg. After equilibration, the plasma concentration is measured to be 0.25 grams per liter. Determine the primary dye distribution (EFV vs IFV).
(A1_5): Extracellular Fluid Volume (EFV) [in the case there is ~17L of EFV, and 17L*0.25g/L is ~4g]
What is the order of components in a classic negative feedback control system?
(A1_6):
- Transducer
- Feedback Element
- Summing Point
- Error Signal
- Control Element
- Control Signal
What percentage of water is contained in the Lean Body Mass (LBM)?
(A1_7): Water is ~73% LBM [since it is 57% TBW and LBM is 79% TBW]
What happens in response to an infusion of hypertonic NaCl Solution?
(A1_8): Expansion of Extracellular Fluid Volume AND reduction of Intracellular fluid volume
A volume of blood is suddenly injected into the circulation, which transiently raises the arterial pressure 50 mmHg instantaneously. However, after the pressure regulating control systems have had time to act, the remaining elevation in pressure is only 5 mmHg. What is the negative feedback gain of this control system? What is the equation for negative feedback gain?
(A1_9): 9 [that is, 45mm/5mm] and the equation is Amount of compensation/steady state error
A diabetic had 2 hour postprandial glucose level at 200mg/dL. After islet transplant, the value changed to 140 mg/dL. If his fasting glucose level is 120 mg/dL, What is his feedback compensation resulted from the transplant? What is the steady state error? What is his feedback gain?
(A1_10): Feedback compensation is 60mg/dL. Steady state error is 20mg/dL. Feedback gain is 3
What is the healthy adipose fraction in males? females?
M: 10-20%
F: 18-25%
What is normal osmolality?
290 mOsmol/kg
Is a higher osmolality correspond with hypertonic or hypotonic? lower osmolality?
higher = hyper lower = hypo
What is hyopnatremia? hypernatremia?
hypo = increased cell volume hyper = dehydration
If there is 7,500 mOsmoles in ICF and 4,500 mOsmoles in ECF. Osmolality is 300 mOsmoles/kg. And we add 1 L of of solution with Osmolality of 1000 mOs/kg. How many Liters of ICF will we have and what will be the final osmolality?
ICF: 23.65 L
Osm: 317 mOs/kg
What adipose fraction is considered obese in males? females?
M: 25%
F: 32%
What is Hematocrit (Hct)?
Amount of blood volume that is red blood cells
If Hematocrit is 45% and 10mg of Evan’s Blue dye is administered, and the concentration of this dye becomes 0.4mg/100mL what is the blood volume of the patient?
4.5L of Blood [BV = PV / (1 - Hct)]
