urinary system 2

Question 1

daily salt intake vs output

Answer 1

salt = sodium and chloride
intake :
in liquids and food = 8.5 grams
total = 8.5 grams

output :
sweat : 0.25 grams
feces : 0.25 grams
urine : 8.0 grams
total : 8.5 grams
dont need to know numbers, trying to balance input vs output

Question 2

sodium

Answer 2

• key ion as many things move in relation
• strong control mechanisms

Question 3

daily water intake vs output

Answer 3

intake : liquids, food, metabolically produced
=2850 mL

output : insensible loss (skin, lungs), sweat, feces, urine
=2850 mL

• *insensible fluid loss** : not normally aware of (evaporation, breathing)
• *sensible fluid loss** : urination/defecation

-strong control mechanisms - tied to ions and hormones

Question 4

tubular reabsorption
proximal tubule

Answer 4

proximal tubule : first part of tubule
-65% sodium reabsorbed
-65% water reabsorbed
-100% glucose reabsorbed
-100 % amino acids reabsorbed

Question 5

acid-base balance

Answer 5

-80% bicarbonate reabsorbed

–secretion of hydrogen and ammonium (variable amount)

Question 6

facilitated diffusion

Answer 6

ex. potassium passing through blue channel
- high concentration to low concentration using a membrane protein

Question 7

primary transport

Answer 7

-ATP broken down to ADP pumps sodium out and potassium in (NA-P pump)
-creates low sodium condition in cell; results in secondary transport that want to respond to low sodium inside.
-X hitches a ride inside with sodium coming in from tubular lumen (cotransport)
(X= glucose or amino acids)

Question 8

countertransport

Answer 8

• going opposite ways
• moving across gradient possible because of low sodium inside

-sodium going into proximal tubule and hydrogen coming into tubular lumen

Question 9

simple diffusion

Answer 9

can move from interstitial fluid to inside blood by simple diffusion
-all of glucose gets absorbed (100%) (X)

Question 10

tubular reabsorption - connected to sodium

Answer 10

sodium change results in lower osmolarity which results in osmosis (water moving through membrane)

• Ion (mainly sodium) movement creates osmotic pressure gradient that draws water along by osmosis

Question 11

obligatory water reabsorption

Answer 11

• follows reabsorbed solutes
• presence of aquaporins (water channels) varies in tubules ; lots in proximal tubules so water can move fairly freely by osmosis
• obligatory water reabsorption mostly in proximal tubule and loop of Henle

-65% water reabsorbed in proximal tubule

Question 12

water movement affecting others ions affecting more water movements

Answer 12

• Initially, water moves following sodium in the proximal tubule
• other ions that can move by simple diffusion follows the water movement in the distal proximal tubule
• water movement alters ion electrochemical gradients (creates gradients for these ions to move)
• when these other ions move they can alter osmotic pressure gradients (like sodium did) and draw even more water along

Question 13

osmolarity

Answer 13

number of particles per unit solution, not a specific particle

Question 14

in proximal tubule lumen

Answer 14

na + moves -> creates lower osmolarity
H20 moves -> creates higher osmolarity
other solutes move -> creates lower osmolarity
more h20 moves

Question 15

ascending limb loop of Henle

Answer 15

25% sodium reabsorbed

Question 16

descending limb loops of henle

Answer 16

15% water reabsorbed (part of obligatory water reabsorption)

Question 17

obligatory water reabsorption

Answer 17

• *~80% total** - 65% in proximal tubule and 15% in descending limb loops of Henle
• moving because “obliged” following other solutes

acid -base balance - 10% bicarbonate reabsorbed in loops of henle

Question 18

na, cl and k

Answer 18

na and chloride reabsorbed (move to loop of henle and interstitial fluid from tubular lumen)
k can be reabsorbed or secreted (facilitated diffusion or atp/adp breakdown or cotransport)

-all three na, cl and k can be reabsorbed and k can also be secreted to lumen

Question 19

last part of it
distal tubule and collecting duct

Answer 19

• 6-9% sodium reabsorbed
• secretion of potassium (variable amount adjusted for dietary intake) (facilitated diffusion)

water
-reabsorption depends on number of aquaporin water channels (variable)

acid-base balance

• bicarbonate reabsorbed (variable amount)
• secretion of hydrogen (variable amount)

Question 20

water -hydration

Answer 20

• *normal hydration - 19%** water absorbed
• *-dehydration - 19.8%** water reabsorbed
• *-overhydration -as low as 0%** water reabsorbed