Digestive System Flashcards
Water Balance
What percentage of a baby’s body weight is water?
What percentage of a young adult’s body weight is water?
What percentage of an obese or elderly’s body weight is water?
What is the total body water (TBW) of a young male in liters?
Water Balance
What percentage of a baby’s body weight is water? ~75% water
What percentage of a young adult’s body weight is water? ~50-60% water
What percentage of an obese or elderly’s body weight is water? As little as 45%
What is the total body water (TBW) of a young male in liters? 40L
Fluid Compartments
The body’s major fluid components:
65% of the body’s fluid is composed of what type of fluid?
35% of the body’s fluid is composed of what type of fluid?
Of that 35%, 25% is what type of fluid?
Of that 35%, 8% is what types of fluid?
Of that 35%, 2% is what type of fluid? In what category? What are some examples?
Fluid Compartments
The body’s major fluid components:
65% of the body’s fluid is composed of what type of fluid? Intracellular fluid (ICF)
35% of the body’s fluid is composed of what type of fluid? Extracellular fluid (ECF)
Of that 35%, 25% is what type of fluid? Tissue (interstitial) fluid
Of that 35%, 8% is what types of fluid? Blood plasma and lymphatic fluid
Of that 35%, 2% is what type of fluid? Trans cellular fluid In what category? “Catch-all” What are some examples? Cerebrospinal, synovial, pericardial
Fluid Compartments
Fluid is continually what?
How does water move?
Because water moves easily, what never lasts long?
What restores balance if imbalances arises?
What do electrolytes help govern?
Fluid Compartments
Fluid is continually what? Exchanged
How does water move? By osmosis
Because water moves easily, what never lasts long? Osmotic gradients
What restores balance if imbalances arises? Osmosis
What do electrolytes help govern? Water distribution and total water content
Movement of Water Between Compartments
Movement of Water Between Compartments
Water Gain & Loss
Fluid balance: gains = what? This is around how many mL a day?
Gains are from what two sources? How many mL/day are they?
Water Gain & Loss
Fluid balance: gains = losses? This is around how many mL a day? ~2,500 mL/day
Gains are from what two sources? Preformed water and metabolic water.
How many mL/day are they? Preformed water = 2,300mL/day and Metabolic water = 200 mL/day
2 Sources of Gains
Preformed water is what 2 things?
Metabolic water is from what to what?
What is the formula for metabolic water?
2 Sources of Gains
Preformed water is what 2 things? Food and drink
Metabolic water is from what to what? Aerobic metabolism and dehydration synthesis
What is the formula for metabolic water?
C6H12O6 + 6 O2 —–> 6 CO2 + 6 H2O
Water Gain & Loss
What are the 3 types of water loss?
Water Gain & Loss
What are the 3 types of water loss? Sensible, insensible, and obligatory water loss
Water Gain & Loss
Sensible water loss is what? 1,500mL/day in what? 200mL/day in what? 100mL/day in what?
Insensible water loss is what? 300mL/day in what? 400mL/day in what, and this evaporates through what and not sweat glands? Insensible water loss varies with what two things?
Obligatory water loss is what? And what does it include?
Water Gain & Loss
Sensible water loss is what? Observable. 1,500mL/day in what? Urine. 200mL/day in what? Feces. 100mL/day in what? Sweat (resting)
Insensible water loss is what? Unnoticed. 300mL/day in what? Breath. 400mL/day in cutaneous transpiration, and this evaporates through epidermis and not sweat glands. Insensible water loss varies with environment and activity.
Obligatory water loss is what? Output unavoidable. And what does it include? All of the above.
Regulation of Intake
What 3 things regulate water intake?
Regulation of Intake
What 3 things regulate water intake? Thirst, dehydration, and osmoreceptors in hypothalamus
Regulation of Intake
Thirst mainly governs what?
Dehydration decreases what and increases what?
Osmoreceptors are found where? Osmoreceptors sense a rise in what? What do osmoreceptors respond to, and when is this thing produced?
Regulation of Intake
Thirst mainly governs what? Fluid intake
Dehydration decreases what and increases what? Decreases blood volume and blood pressure. Increases blood osmolarity.
Osmoreceptors are found where? In the hypothalamus. Osmoreceptors sense a rise in what? Osmolarity of ECF. What do osmoreceptors respond to, and when is this thing produced? Angiotensin II - produced when blood pressure drops
Regulation of Intake
What does the hypothalamus produce and what does it inhibit? Is what it inhibits sympathetic or parasympathetic?
How does the cerebral cortex make us feel? This intense sense, if only 2-3% increase in what?
Regulation of Intake
What does the hypothalamus produce and what does it inhibit? Produces ADH. Inhibits salivation. Is what it inhibits sympathetic or parasympathetic? Sympathetic
How does the cerebral cortex make us feel? Thirst. This intense sense, if only 2-3% increase in what? Plasma osmolarity.
Regulation of Intake
Regulation of Intake
Regulation of Intake
Long-term inhibitation of thirst is an absorption of water from where? What does it reduce? What does it stop? How long does it take?
Short-term inhibitation of thirst is the what and what of the mouth? Distension of what 2 things? By when do you get relief? Water must soon be absorbed into what or what returns?
Short-term response is designed to prevent what?
Regulation of Intake
Long-term inhibitation of thirst is an absorption of water from the small intestine? What does it reduce? Blood osmolarity. What does it stop? Osmoreceptors. How long does it take? Over 30 minutes
Short-term inhibitation of thirst is the cooling and moistening of the mouth? Distension of what 2 things? Stomach and small intestines. By when do you get relief? 30 minutes. Water must soon be absorbed into the blood or thirst returns?
Short-term response is designed to prevent overdrinking.
Dehydration, Thirst, Rehydration
Dehydration, Thirst, Rehydration
Regulation of Output
A significant control of water output is what? What cannot replace water or electrolytes? What type of rate of loss?
Mechanism:
- Changes in urine volume are usually are linked to adjustments in what type of reabsorption? As this is reabsorbed or excreted, what follows?
- Can concentrate urine with what, independently of what? In CDs, water is what, and what is still excreted?
Regulation of Output
A significant control of water output is variation in urine volume. What cannot replace water or electrolytes? Kidneys. What type of rate of loss? Slow.
Mechanism:
- Changes in urine volume are usually are linked to adjustments in Na+ reabsorption. As this is reabsorbed or excreted, water follows.
- Can concentrate urine with ADH, independently of Na+. In CDs, water is reabsorbed, and Na+ is still excreted.
Dehydration from Excessive Sweating
Sweat from ___
What 2 things drop and what rises?
What absorbs tissue fluid to replace loss?
Where is tissue fluid pulled from?
Which compartments lose water?
Dehydration from Excessive Sweating
Sweat from capillaries
What 2 things drop and what rises? Blood volume and BP drops, osmolarity rises
What absorbs tissue fluid to replace loss? Blood
Where is tissue fluid pulled from? ICF
Which compartments lose water? All 3
Disorders of Water Balance
What is less common than fluid deficiency?
What is so effective at excreting more urine to compensate for excessive intake?
What can cause fluid retention?
Disorders of Water Balance
What is less common than fluid deficiency? Fluid excess
What is so effective at excreting more urine to compensate for excessive intake? Kidneys
What can cause fluid retention? Renal failure
Fluid Sequestration
Fluid sequestration is when excess fluid what? Name and describe the most common form.
What is it called when blood pools in tissues?
What is an example of effusion?
Fluid Sequestration
Fluid sequestration is when excess fluid what? Accumulates in a particular location (compartment). Name and describe the most common form. Edema - abnormal accumulation of interstitial fluid
What is it called when blood pools in tissues? Hemorrhage
What is an example of effusion? Fluid in pleural cavity
Sodium
Sodium is a critical ion for what? What type of pump?
Principal cation in what?
90-95% of osmolarity of what?
Sodium is the most significant solute in determining total (and distribution of) what?
Sodium
Sodium is a critical ion for what? RMPs, APs What type of pump? Na+-K+ pump
Principal cation in what? ECF
90-95% of osmolarity of what? ECF
Sodium is the most significant solute in determining total (and distribution of) body water
Sodium
What type of gradient is a source of potential energy for cotransport of others (glucose, K+, & Ca2+)?
Sodium
What type of gradient is a source of potential energy for cotransport of others (glucose, K+, & Ca2+)?
Na+ gradient source
Sodium
Sodium
Sodium
Sodium imbalances are relatively rare but…
What are the consequences of hypernatremia?
What are the consequences of hyponatremia? This is quickly corrected by what?
Sodium
Sodium imbalances are relatively rare but…
What are the consequences of hypernatremia? Hypertension, edema
What are the consequences of hyponatremia? Drinking too much plain water after profuse sweating. This is quickly corrected by what? Excretion of excess water
Potassium
Potassium is a critical ion for what?
Potassium is the principal cation of what?
Potassium
Potassium is a critical ion for RMPs, APs
Potassium is the principal cation of ICF.
Potassium
Homeostasis— closely linked to that of…
Most K+ is reabsorbed by what?
• DCT & collecting duct secrete K+ in response to what, mediated by what?
Potassium
Homeostasis— closely linked to that of Na+
Most K+ is reabsorbed by PCT
• DCT & collecting duct secrete K+ in response to blood levels, mediated by aldosterone.
