Exam 1: Lecture 4 Flashcards
Decrease Na intake leads to a ___ Na balance and
eventual ECF ____
negative; contraction
Increase Na intake leads to a ___ Na balance and eventual ECF ____
positive; expansion
Without the kidneys, changes in
dietary Na will result in ______ to maintain osmolarity.
excessive ECF expansion (or contraction)
Hypernatremia is associated with
A. Hyperosmolarlity
B. Hyposmolarity
A. Hyperosmolarlity
What is the best defense against hypernatremia?
A. Eating salty foods
B. Drinking water
C. Drinking gatorade
B. Drinking water
Patients with Syndrome of Inappropriate ADH will typically present as:
A. Hypovolemic-hyponatremic
B. Euvolemic-hypernatremic
C. Euvolemic-hyponatremic
C. Euvolemic-hyponatremic
What would you expect to see in a person with Syndrome of Inappropriate ADH?
A. Excessive water loss
B. Excessive water gain
B. Excessive water gain (retention)
How do you treat Syndrome of Inappropriate ADH?
1) Limit water intake
2) Block V2R receptor at the collecting duct (Tolvaptan)
True or False: Polydipsia can cause hypernatremia
False: Polydipsia can cause hyponatremia
When plasma osmolarity decreases, what happens to ADH concentrations?
Is there an increase or decrease in fluid loss?
Decrease
Increased fluid loss
_____: Volume expansion in the presence of low serum Na+
A. Hypervolemic
B. Hypovolemic
C. Euvolemic
A. Hypervolemic
What are common causes of hypervolemic-hyponatremia
Heart failure and cirrhosis
Heart failure results in
low cardiac output and a decrease in blood pressure stimulating the ___
RAAS
Cirrhosis is associated with peripheral arterial ____ and a reduction in___; baroreceptors respond by increasing the release of ___
vasodilation
blood pressure
ADH
Elevated ANP/BNP and edema would be visible in a patient with:
A. Euvolemic-hyponatremia
B. Hypervolemic-hyponatremia
C. Hypovolemic-hyponatremia
B. Hypervolemic-hyponatremia
____: Normal plasma volume with low serum Na+. It is characterized by inappropriate and persistent ADH release
Euvolemic-hyponatremia
CNS disease or malignant tumor secreting ADH is associated with:
A. Euvolemic-hyponatremia
B. Hypervolemic-hyponatremia
C. Hypovolemic-hyponatremia
A. Euvolemic-hyponatremia
Inappropriate ADH
secretion leads to retention of ____ and _____.
Secondary mechanisms induce ___ and __ excretion to restore euvolemia, but results in
____.
Na+ ; water
volume expansion
hyponatremia
Na in plasma is low; < 135mEq/L is associated with:
A. Hypovolemic-Hyponatremia
B. Euvolemic-Hyponatremia
C. Hypervolemic-Hyponatremia
A. Hypovolemic-Hyponatremia
What causes Hypovolemic-Hyponatremia?
A. Dehydration (sweating, burn, vomit, diarrhea, thiazide diuretics)
B. Overhydration (polydipsia)
C. ADH secreting tumor
D. hypercholesteremia
A. Dehydration (sweating, burn, vomit, diarrhea, thiazide diuretics)
Low urine [Na] <30mEq/L, Orthostatic intolerance, and dry mucous membranes are associated with:
A. Hypovolemic-Hyponatremia
B. Euvolemic-Hyponatremia
C. Hypervolemic-Hyponatremia
A. Hypovolemic-Hyponatremia
How is Hypovolemic-Hyponatremia treated?
A. Water intake
B. Saline infusion
C. Restrict water intake
B. Saline infusion
_____: Na in total plasma fraction is low due to hyperlipidemia
Pseudo-Hyponatremia
True or False: In Hypertonic-Hyponatremia, Na in plasma is reduced due to addition of effective osmole to plasma (e.g radiographic contrast agents)
True
Normal plasma Na+ concentration is:
A. 125-135 mEq/L
B. 135-145 mEq/L
C. 145-155 mEq/L
D. 155-165 mEq/L
B. 135-145 mEq/L
What is the most common disorder of electrolytes?
Hyponatremia
What causes low sodium?
Increased water intake and increased excretion/loss of sodium
Which of the following is incorrect regarding the countercurrent mechanism?
A. Salty medulla creates ionic gradient for urine concentration
B. ADH helps with water retention when dehydrated
C. ADH release leads to a concentrated urine
D. Thick ascending limb is permeable to water
E. Na/K/2Cl co transporter is needed for CC mechanism
D. Thick ascending limb is permeable to water
Which structure senses fullness?
A. Detrusor muscle
B. Sensory Afferents
C. Somatic (Pudenal) Nerve
D. Efferent Nerves
B. Sensory Afferents (both the sympathetic and parasympathetic)
Which structure relaxes the detrusor muscle to store urine?
A. Parasympathetic Afferent
B. Hypogastric Nerve
C. Sympathetic Efferent
D. Parasympathetic Efferent
C. Sympathetic Efferent
Which system is responsible for contracting the internal sphincter to store pee?
A. Sympathetic (Hypogastric) Nerve
B. Parasympathetic (Sacral/Pelvic) Nerve
C. Parasympathetic Efferent
A. Sympathetic (Hypogastric) Nerve
Which structure contracts the detrusor muscle to urinate?
A. Parasympathetic Afferent
B. Hypogastric Nerve
C. Sympathetic Efferent
D. Parasympathetic Efferent
D. Parasympathetic Efferent
Which nerve regulates the external sphincter and becomes under voluntary control at ~age 2 or 3?
A. Sacral Nerve
B. Pelvic Nerve
C. Hypogastric Nerve
D. Pudenal Nerve
D. Pudenal Nerve
True or False: When the bladder is empty, there is no stretch, sensory afferent signals, or contraction of detrustor
True
True or False: As the bladder fills, sympathetic nervous system afferents begin to cause mild reflexive contractions
False - As the bladder fills, parasympathetic nervous system afferents begin to cause mild reflexive contractions
Which structure sends inhibitory signals to the detrusor muscle to relax?
A. Parasympathetic Afferent
B. Hypogastric Nerve
C. Sympathetic Efferent
D. Parasympathetic Efferent
C. Sympathetic Efferent
Contraction of bladder via pudenal nerve results in:
A. Urination
B. Storing urine
B. Storing urine
When the bladder is full, signaling by which structure causes frequent and forceful contractions of detrusor muscle?
A. Parasympathetic Afferent
B. Hypogastric Nerve
C. Sympathetic Efferent
D. Parasympathetic Efferent
A. Parasympathetic Afferent
If SNS efferents no longer inhibit detrusor contractions, what happens to the internal sphincter?
A. Contracts
B. Relaxes
C. None of the above
B. Relaxes
If pudenal nerve is inhibited, what happens to the external sphincter?
A. Contracts
B. Relaxes
C. None of the above
B. Relaxes
(and urination occurs)
Which of the following is incorrect?
A. The detrusor muscle surrounds the bladder and assists with voiding
B. The internal sphincter is NOT under voluntary control, tone prevents voiding
C. External sphincter is innervated by pudenendal nerve and is under voluntary control by age 3
D. Parasympathetic efferents are active during filling and inactivated during voiding
D. Parasympathetic efferents are active during filling and inactivated during voiding
Hypovolemic-Hypotonic-Hyponatremia is associated with which of the following:
A. Hyperlipidemia
B. Recent infusion of radiographic contrast
C. Tumor cause secretion of ADH
D. Burn injury, diarrhea, vomitting
E. Uncontrolled diabetes
F. None of the above
D. Burn injury, diarrhea, vomitting
Euvolemic Hypotonic Hyponatremia is associated with which of the following:
A. Hyperlipidemia
B. Recent infusion of radiographic contrast
C. Tumor cause secretion of ADH
D. Burn injury, diarrhea, vomitting
E. Uncontrolled diabetes
F. None of the above
C. Tumor cause secretion of ADH
Hypervolemic-Hypotonic Hyponatremia is associated with which of the following:
A. Hyperlipidemia
B. Recent infusion of radiographic contrast
C. Tumor cause secretion of ADH
D. Burn injury, diarrhea, vomitting
E. Heart failure -> low BP -> increase in RAAS
F. None of the above
E. Heart failure -> low BP -> increase in RAAS
When urine is being diluted, is the filtrate in the thick ascending limb:
A. hyper-osmolar
B. hypo-osmolar
C. iso-osmolar
B. hypo-osmolar
(reabsorption of solutes without water)
When urine is being diluted, is there high or small volume of urine? Is urine hyperosmotic or hypo-osmotic?
High volume of urine
Urine is hypo-osmotic
Under dehydration conditions, reduced BP leads to release of which molecule?
A. NAP
B. BVP
C. ADH
C. ADH
True or False: ADH leads to insertion of aquaporin in collecting tubule and reabsorption of glucose in the medulla
False - reabsorption of urea
When urine is being concentrated, will there be a high or low urine volume? Will urine be hyper-osmotic or hypo-osmotic?
Low urine volume, hyper-osmotic
True or False: Urea plays a major role in establishing countercurrent
True
Consuming which food would reduce ADH secretion?
A. Watermelon
B. Hamburger and Fries
C. Salt water
D. Chips
A. Watermelon
Where does ADH mediated insertion of AQP2 channels occur?
A. Proximal Tubule
B. Loop of Henle
C. Medulla (collecting tubule)
D. Macula Dense
E. Renal Cortex
C. Medulla (collecting tubule)
Which of the following leads to water retention?
A. Baroreceptors
B. Osmoreceptors
C. Hypothalamus
D. Pituitary Gland
E. All of the above
E. All of the above
True or False: The salty medulla is created by countercurrent mechanism
True
The proximal tubule is a major site of water reabsorption. What creates the osmotic gradient that drives water reabsorption?
Na/K ATPase
What prevents the formation of large ionic gradients in the proximal tubule?
A. High permeability
B. Low permeability
C. Iso-osmolar volume
A. High permeability
ADH binds to receptors on which cell type?
A. Intercalated Cells
B. Hypothalamic Osmoreceptors
C. Principal Cells
C. Principal Cells (in CT)
Is collecting duct typically water permeable?
No - only becomes water permeable with ADH
ADH secretion is very sensitive to changes above
A. 200 mOsmo
B. 250 mOsmo
C. 280 mOsmo
D. 300 mOsm
C. 280 mOsmo
Thirst is driven at:
A. 200 mOsmo
B. 260 mOsmo
C. 290 mOsmo
D. 310 mOsm
C. 290 mOsmo
True or False: Hypothalamic osmoreceptors are activated in response to low plasma osmolarity.
False - activated in response to high plasma osmolarity
True or False: When high blood pressure is sensed by arterial and atrial baroreceptors, ADH is released
False: When low blood pressure is sensed by arterial and atrial baroreceptors, ADH is released
Increase water reabsorption in the absence of low volume or pressure will dilute plasma, leading to:
Hyponatremia
What is normal plasma osmolarity?
280-295 mOsm
____: Large urine volume, usually dilute
____: Small urine volume, usually concentrated
Diuresis: Large urine volume, usually dilute
Anti-diuresis: Small urine volume, usually concentrated
What happens to urea transport and urinary concentrating power if NaCl transport out of the ascending limb is impaired??
-Urea transport out of collecting duct is impaired
-Urinary concentrating power is decreased
The release of ADH from the posterior pituitary
is primarily regulated by what two structures?
1) hypothalamic osmoreceptors
2) arterial and atrial baroreceptors
____: detect changes in plasma osmolality
Osmoreceptors in the hypothalamus
Osmoreceptors in the hypothalamus send signals via the _____to increase or decrease
ADH release
supraoptic and paraventricular neurons
When osmolality is <280mOsm
(hypotonic), ADH secretion is _____
almost zero
Which sphincter is innervated by the pudenal nerve?
External sphincter
Is the internal sphincter under volunary or involuntary control?
involuntary control
What prevents emptying of bladder until pressure in the fundus reaches a critical
threshold?
Tonic tone
Parasympathetic efferents are very active during
___ and are inhibited during ____
voiding; filling
Sympathetic activity is active during ___ of
the bladder. It is inhibited during _____
filling; voiding
_____: a spinal reflex that is substantially modified by higher brain centers, including the brainstem (pontine micturition center), hypothalamus and
cortical areas.
The micturition reflex
True or False: As the bladder fills, the smooth muscle is stretched outward, bladder pressure increases, and sacral sensory afferents are stimulated
True
In a child without bladder control, the resultant stretching of the urethra sends a second
signal to the spinal cord to inhibit the tonically-active alpha-motor neurons innervating
the ______
external sphincter
Relaxation of the external sphincter leads to ____
voiding
True or False: In a person with intact brain function, the learned, voluntary control of the micturition reflex (i.e. control of the external sphincter) overrides the afferent signals and the external sphincter remains contracted until it is appropriate to micturate.
True
