Exam 6 & 7 Flashcards
what is transport maximum?
specific and limited number that reflects the number of carriers in renal tubules that are available
what hormones affect reabsorption in the renal tubules and collecting ducts?
Atrial natriuretic peptide ANP. parathyroid hormone, ADH, aldosterone
What does ANP do? what hormone is antagonistic to ANP?
ANP is released by cardiac atrial cells and reduces blood Na+ resulting in decreased blood volume and blood pressure. Aldosterone is antagonistic.
what does the parathyroid hormone do?
Acts on DCT to increase Ca2+ reabsortion
what does ADH do?
Increases permeability of water in the DCT and collecting duct to produce concentrated urine. low ADH makes DCT and collecting duct less permeable therefore urine is less concentrated
what does aldosterone do?
Reabsorption of Na+ in the DCT
if someone is losing electrolytes which hormones would be increased in the blood?
Aldosterone and ADH
which hormones raise and lower BP?
angiotensin, aldosterone, ADH raise BP. ANP lowers BP.
where does most reabsorption occur?
PCT
which part of the renal tubule is water reabsorption hormonally controlled
DCT and collecting duct
what is the countercurrent mechanism and what are the two parts of it?
The countercurrent mechanism consists of the descending and ascending portions of the nehron loop. The interaction of filtrate creates a gradient, and the countercurrent mechanism is the blood flow in the descending, ascending and vasta recta which preserves the gradient.
what is the medullary osmotic gradient from the cortex to the renal medulla?
It runs from 300 mOsm in the cortex to 1200 mOsm in the medulla
how does the medullary osmotic gradient affect the collecting duct?
The collecting duct uses the gradient to adjust urine osmolality.
what events happen when you are overhydrated?
decreased osmolality (concentration of particles) of extracellular fluid >decrease in ADH release from posterior pituitary> decreased number of H2O channels in collecting ducts> decreased reabsorption from collecting ducts> produce a large amount of concentrated urine
what happens when you are dehydrated?
increased osmolality of extracellular fluid> increased ADH released from posterior pituitary> increased number of H2O channels> reabsorption from collecting duct> produce a small amount of concentrated urine
what is the result of hypoproteinemia?
low levels of plasma protein can lead to tissue edema because fluid would not be removed from cells
in case of albuminuria (protein albumin in urine), what would happen to the osmotic pressure in the blood?
since the albumin would appear in the urine it would no longer be present in the blood and the osmotic pressure would decrease
what is the function of the ureter
helps urine produced from the kidney travels to the urinary bladder via peristasis
what are the layers of the of the ureter?
mucosa (epithelium), muscularis (smooth muscle), and outer adventia
what type of epithelium lines the ureter?
transitional epithelium
If someone has a kidney stone that blocks their ureter urine wont flow into what part of the urinary system?
urinary bladder
what is the purpose of the urinary bladder?
temporary storage for urine that can hold up to 500ml of urine
where is the location of the urinary bladder?
retroperitoneally posterior to the pubic symphysis
what is the trigone?
triangular shaped structure at the base of the urinary bladder with 2 ureteral openings and 1 urethral
what is the makeup of the epithelium of the urethra?
Transitional epithelium near the opening of the bladder and stratified squamous epithelium near the external urethral orifice.
what is the difference between a male and females’ urethras?
male urethra is longer
what are the parts of the male urethra?
prostatic urethra, membranous urethra, and penile spongy urethra
what is micturition (action of urinating) and what triggers it?
emptying of bladder, excitation of parasympathetic nervous system that causes contraction of the detrusor muscle and relaxation of the internal urethral sphincter.
How much fluid makes of the ECF and what does it contain? What are the major ions in the ECF?
The ECF is 20% of our body weight. 80% of interstitial fluid and 20% plasma.
K+ and HPO42-
What direction does water move when the ECF osmolarity increases
water leaves the cell by osmosis
what is the result of this water movement?
cells shrink (crenate)
what direction does water move when the ECF osmolality decreases
water enters the cell by osmosis and cell swells
what does a rise in osmolality do to the body?
rise is osmolality stimulates the thirst center in the hypothalamus
what hormone is released?
ADH is released
What does a drop in osmolality do to the body? what hormone is released?
decrease in osmolality inhibits the thirst center of the hypothalamus. ADH is inhibited
what are the major sources and amounts of water intake? what are the major sources and output of water?
10% metabolism (250ml), 30% foods (750ml) and 60% beverages 91500ml) intake
feces 4% (100ml), sweat 8% (200ml), insensible loss via skin and lungs 28% (700ml), urine 60% (1500ml)
where is the thirst mechanism located?
hypothalamus
what is the main stimulus that activates the thirst center?
major physiological factors include a rise in plasma osmolality and other stimuli like a dry mouth, decreased blood volume or pressure, angiotensin 11 or baroreceptor input
what effect will drinking excessive quantities of water have? hat effect will drinking very little water have?
excessive amounts- it will cause ADH levels to be low and DCT and collecting ducts to be impermeable to water.
little water- It will causes ADH levels to be high and the DCT and collecting ducts to be permeable to water.
what are some causes and consequences of hypernatremia? (increased sodium concentration in the blood)
Dehydration or excessive IV Nacl: this can lead to CNS dehydration which could lead to confusion and lethargy as well as increased neuromuscular irritability
what are some causes and consequences of hyponatremia?
vomiting, diaherra, burned skin or anything that leads to loss of electrolytes
what are some causes and consequences of hyperkalemia (High potassium levels in the blood.)
renal failure, deficit of aldosterone that could lead to vomiting, diarrhea, or reduced excitability
what are some causes and consequences of hypokalemia? (Below normal blood potassium level)
GI disturbances, gastric suction, cushings syndrome that could lead to cardiac arrhythmias, non responsiveness, flattened T waves on ECG
what are some causes and consequences of hyperphospatemia? (elevated amount of phosphate in blood)
decreased urine loss, hypoparathyroidism, reciprocal changes in ca2+ levels
what are some causes and consequences of hypophospatemia?
decreased intestinal absorption, hyperthyroidism
what are some causes and consequences of hyperchloremia?
dehydration, metabolic acidosis (related to H abnormalities) excess of chloride in blood)
What are some causes and consequences of hypochloremia
Metabolic alkalosis due to vomiting or aldosterone deficiency
What are some causes and consequences of hypercalcemia?
Burns, vitamin D deficiency leading to tingling fingers , tremors, and skeletal cramps
What are some causes and consequences of hyper magnesium
Renal failure, can lead to lethargy and impaired CNS
What are some causes of hypomagnesemia
Alcohol, chronic diarrhea, can lead to tremors and convulsion
What is the primary regulator for ECF na+ concentration
ADH and thirst mechanisms
Sodium is related to
Blood pressure
Where is 65% of na+ reabsorbed
PCT
Where is 25% of sodium reabsorbed
Nephron loop
When blood pressure increases, how do cardiovascular baroreceptors respond
Afferent arterioles dilate, GFR increases, blood volume and pressure drop
What is the normal PH range in the blood stream
7.35-7.45
What is the measurement of PH in the blood
Number of free H+ ions
What would the PH for alkalosis be
Greater than 7.45
What would the PH for acidosis be
Less than 7.35
What are the 3 methods for regulating H+ in the blood
Chemical buffer, brain system centers, renal mechanisms
How does a chemical buffer system work
Prevents a radical change in fluid PH by dampening the change in hydrogen ion concentrations in the case of excess acid or base. To much acid will
What does the body do in response to hypercapnia (to much C02 in blood)
Your body will activate your medullary chemoreceptors to increase respiratory rate and depth
What does hyperventilation cause
Respiratory alkalosis
What does hypoventilation cause
Respiratory acidosis
How are lactic acids and ketones removed from the body
The kidney
How does the nephron respond to ketoacidosis (body produces excess blood acids)
Secrete H+ ions
What are the main signs and causes of metabolic acidosis (to much acid builds in the body)
Low bicarbonate, severe diarrhea (losing bicarbonates) untreated diabetes mellitus
What are the main signs and causes of metabolic alkalosis
High bicarbonate, the use of diuretics and the external loss of gastric secretions by vomiting and gastric suctioning, ingestion of excessive antacids, excessive aldosterone
