solute transport: reabsorption and secretion Flashcards
(56 cards)
1
Q
SIMPLE DIFFUSION
A
- net movement represents molecules or ions moving down their electrochemical gradient
- from higher concentration to lower concentration
- e.g respiratory diseases
2
Q
FACILITATED DIFFUSION (passive process)
A
molecule or ion moving ACROSS a membrane down its electrochemical gradient ATTACHES TO A SPECIFIC MEMBRANE BOUND PROTEIN
3
Q
ACTIVE TRANSPORT
A
- PROTEIN MEDIATED TRANSPORT THAT USES ATP AS A SOURCE OF ENERGY to move a molecule or ion agains its electrochemical gradient
- movement from LOWER concentration to HIGHER concentration
4
Q
PROTEIN MEDIATED TRANSPORT
A
- uniport
- symport
5
Q
FACILITATED TRANSPORT
A
- uniport
- moves a SINGLE MOLECULE or ions IN ONE DIRECTION
- e.g. uptake of glucose into skeletal muscle or adipose tissue
- calcium into skeletal muscle
- ATPase provides energy
6
Q
symport (cotransport)
A
- coupled protein transport of 2+ solutes in the same direction
- e.g. Na-glucose, Na-amino acid transporters
- occurs in the kidney or small intestine
7
Q
transport maximum (TM) is directly proportional to
A
- carried saturated
- number of functioning transporters (e.g. insulin)
facilitated diffusion
8
Q
concentration of substance is directly proportional to
A
- transport rate
9
Q
chemical specificity occurring in simple diffusion
A
- the substance must have a certain chemical structure
- ONLY NATURAL ISOMER will be transported
- e.g. D-glucose not L-glucose
10
Q
competition for carriers for protein mediated transport
SIMPLE DIFFUSION
A
- glucose and galactose will generally compete for the same transport protein
- glucose on the membrane add galactose to the medium decrease the rate
11
Q
PRIMARY ACTIVE TRANSPORT
A
- ATP is CONSUMED DIRECTLY by transporting protein
- e.g. Na/K-ATPase pump, calcium-dependent ATPase pump of the SR (uniport)
- HAS ATPase activity
12
Q
SECONDARY ACTIVE TRANSPORT
A
- DEPENDS INDIRECTLY on ATP as a source of energy
e. g. Na-glucose (COTRANSPORT) in proximal tubule, that depends on ATP utilized by Na/KATPase pump - NO ATPase activity
- high concentration outside low concentration inside
13
Q
co- transport
A
- substance moved on the same direction
14
Q
counter-transport
A
- substance moved on different direction
15
Q
from lower concentration to higher concentration
A
- active transport secondary to the pumping of Na in the basal membrane
16
Q
increase luminal concentration is proportional to
A
- gradient, and uptake
17
Q
H+ moved up a concentration gradient
A
- secondary active tranport
18
Q
reabsorption of Na
A
- in the proximal tubule
19
Q
Transport Maximum System (TM)
A
- carriers are saturated
- carriers have a high affinity for substrate
- there is low back leak
concept: the entire filtered load is reabsorbed until the carriers are saturates then the excess is excreted - number of functioning carriers
20
Q
low back leak
A
- is the back diffusion of the substance into the tubule after it is reabsorbed into the interstitium
21
Q
minimal back leak
A
- back leak of glucose occurs because the proximal tubule is not permeable to glucose
22
Q
glucose concentration is plasma is directly proportional to AKA renal threshold or plasma threshold
A
- glucose rate being filtered
- is a passive process (FACILITATED DIFFUSION) into bowman’s capsule
- plasma glucose are saturated
23
Q
removing one KIDNEY
A
- loss 50% of functioning nephrons
- loss 50% of carriers pumping glucose
- TM 50%
24
Q
TM is the index of
A
- number of functioning nephrons
25
SPLAY
- curved in the plateau
- due to unsaturated nephrons at the same time
- there is saturated at the same time unsaturated nephrons
26
glucosuria (excretion)
- filtered is > reabsorbing glucose
- at the beginning of splay
- at the renal or plasma threshold
27
the higher the plasma concentration of glucose
- the higher the glucose filtration rate
28
lowest level of plasma glucose where reabsorbing at TM
- after splay
29
lowest level of plasma glucose where glucose is appearing in the urine
- at the splay
| - reabsorbing at a rate below TM
30
increase GFR
- increase load delivered to all nephrons
| - renal threshold decrease
31
pregnancy
- increase GFR
| - decrease renal threshold
32
GFR is inverse to
- renal threshold
33
UREA
- freely filtered
- partially reabsorbed
- passive diffusion
34
diuresis
- urea excretion
35
proximal reabsorption of sodium
- gradient time system
- low affinity to substrate
- 2/3 or 66% are reabsorbed in the proximal tubule
36
proximal tubules
- Na pumping (most O2 and ATP consumed by the kidney goes into this pump)
- K
- Cl
- water
37
GFR determines the
- metabolic load of the kidney
| - the filtered load of sodium
38
PAH
- is freely filtered
| - impossible to be reabsorbed
39
PAH infusion 1000x (over infusion) to a patient to calculate the clearance for renal plasma flow
- GFR
40
PAH clearance at low plasma concentration is called
- effective renal plasma flow (ERPF)
41
compounds compete with PAH as an additive to lessen the effect of a drug
organic anion
- penicillin
- furosemide
- acetazolamide
- salicylate
42
compounds compete with PAH as an additive to lessen the effect of a drug
organic cations
- atrophine
- morphine
- procainamide
- cimetidine
- amiloride
43
filter load
= GFR x Px amt /volume mg/ml
44
excretion
= Ux urine concentration of substance x V urine flow
45
freely filtered but no transport
- sucrose
| - mannitol
46
the secretion rate of INULIN
- always equals the filtration rate of INULIN
47
uncontrolled diabetic excretion of glucose
- is always to be less than the filtered load
48
diabetic but no glucose in the urine
- all of the filtered glucose is reabsorbed
| - the filtration rate must equal the reabsorption rate
49
creatinine
- index of GFR clinically
| - tiny amount is secreted
50
secretion of PAH is always > than
- the filter load
51
20% OF filtered in the kidney is
- completely reabsorbed
52
protein
- non is filtered nor reabsorbed
| - 100 % will be excreted
53
sodium always appears
- in the urine
54
waters follows
- sodium
55
urea follows
- water
56
western diet forming (high meat)
- acid urine
