Final: Cont. Flashcards by Rachel Smith

Hydrostatic P in glomerular capillaries

45 mm HG

How well did you know this?

Not at all

Perfectly

Hydrostatic P in Bowman’s space

10 mm HG

How well did you know this?

Not at all

Perfectly

Glomerular filtration rate

180 L day = 125 ml/min

How well did you know this?

Not at all

Perfectly

Filtered load

Amount of substance filtered across glomerular capsule

How well did you know this?

Not at all

Perfectly

Tubular fluid

Fluid in Bowman’s space and lumen of nephron

How well did you know this?

Not at all

Perfectly

Mechanisms of action for reabsorption

Transporters in membrane of tubular epithelial cells

How well did you know this?

Not at all

Perfectly

Most important function of kidneys and why

Reabsorb Na -> drives reabsorption of everything else

How well did you know this?

Not at all

Perfectly

Major cation in ECF

How well did you know this?

Not at all

Perfectly

Increase in Na intake = increase in

Volume

How well did you know this?

Not at all

Perfectly

Examples of substances secreted from peritubular blood into tubular fluid via tubular epithelium

Organic acids
Organic bases
K+

How well did you know this?

Not at all

Perfectly

Cellular mechanism for glucose reabsorption

Carrier mediated along with Na in early PT

from tubular fluid into tubular cell via Na/glucose symporter SGLT
2 Na (downhill) and 1 glucose (uphill)
Na/K pump on peritubular capillaries side keeps Na low in ICF
secondary active transport

How well did you know this?

Not at all

Perfectly

Glucose transported from tubular cell into peritubular blood by

Facilitated diffusion

GLUT 1 and 2 ( insulin dependent)

How well did you know this?

Not at all

Perfectly

Splay on glucose titration curve

Bending of reabsorption curve

Threshold - not all glucose reabsorbed

How well did you know this?

Not at all

Perfectly

Reasons for splay

Low affinity of Na glucose cotransporter

Heterogeneity of nephrons

How well did you know this?

Not at all

Perfectly

Glucosuria definition and observed in what conditions

High plasma glucose >200 mg/dL (DM)

Pregnancy (increased GFR which increases filtered load)

Congenital abnormalities of Na/glucose cotransporter

How well did you know this?

Not at all

Perfectly

___ freely filtered across glomerular capillaries

Urea

How well did you know this?

Not at all

Perfectly

__ transported in most segments of nephron

Urea

How well did you know this?

Not at all

Perfectly

Concentration of urea increases in tubular fluid as water is

Reabsorbed from tubule

How well did you know this?

Not at all

Perfectly

Urea secreted in

Thin descending limb

How well did you know this?

Not at all

Perfectly

Structures impermeable to urea

Thick ascending limb
Distal tubule
Cortical CD
Outer medullary CD

How well did you know this?

Not at all

Perfectly

More urea is secreted than was reabsorbed by

PCT

How well did you know this?

Not at all

Perfectly

Inner medullary collecting ducts have urea transporter 1 which is activated by

ADH

How well did you know this?

Not at all

Perfectly

Urea can by __ at high levels

Toxic

How well did you know this?

Not at all

Perfectly

__ and __ help create osmotic gradient at loop of Henle so water can be reabsorbed

Urea and salt

How well did you know this?

Not at all

Perfectly

Para-aminohippuric acid (PAH)

Used to measure renal plasma flow

90% of PAH in blood bound to

Plasma proteins - not filterable

Only ___ of PAH is filterable

10%

PAH secretion

Transporters in peritubular membranes of PT cells Inhibited by probenecid

Excretion of PAH

Rises sharply as unbound plasma PAH levels rise

Weak acids

PAH | Salicylic acid

Weak bases

Quinine | Morphine

Only ____ species of weak acids and bases can diffuse across tubular cells

Uncharged species

Aspirin reabsorption

HA form = salicylic acid - reabsorbed A- form = salicylate = not reabsorbed

Positive Na balance

Excretion < intake

Negative Na balance

Excretion > intake

Positive Na balance; excess Na accumulates where

ECF = Increase BV and BP Possible edema

Negative Na balance; Na lost from

ECF

Maintenance of ___ essential for normal function of excitable tissue

Most (98%) of K is where

ICF

___ major cation that exchanges for H

Shifts of K from ICF to ECF

``` Insulin deficiency Beta 2 adrenergic antagonists Alpha adrenergic agonists Acidosis Hperosmolariry Cell lysis Exercise ```

Shifts of K from ECF to ICF

``` Insulin Beta 2 adrenergic agonsits Alpha adrenergic antagonsits Alkalosis Hypoosmolarity ```

___ increases activity of Na/K ATPase

Insulin

High levels of insulin can result in

Hypokalemia

Type 1 DM can result in

Hyperkalemia

Insulin helps move ingested ___ into cells to prevent ____ after K rich meal

K Hyperkalemia

Acid base abnormalities are often associated with

K abnormalities

K disturbances do not occur in ___ or ___

Respiratory acidosis or alkalosis

K is not bound and freely filtered at

Glomerular capillaries

___ reabsorbed 67% fo filtered load of K

PCT

__ reabsorbs 20% of filtered load of K

Thick ascending limb

Final adjustments to K secretion occurs in

Distal tubule and collecting duct

K reabsorption occurs via

Alpha intercalated cells

K secretion occurs by

Principe cells

Loop diuretics and thiazide diuretics

Increase K excretion leading to hypokalemia Produce profound kaliuresis and hypokalemia

Thick AL impermeable to

Water

Increase plasma osmolarity stimulates osmole receptors in

Anterior hypothalamus

Vasa recta

Capillaries that serve medulla and papilla

3 actions of ADH on renal tubule

1. Increase water permeability of principal cells in Lae DT and CD 2. Increase activity of Na/K/Cl cotransporter of TAL 3. Increase urea permeability in inner medullary CD

In nephron free water generated in

Diluting segment

ADH low and effect on free water clearance

All free water excreted -> cannot be reabsorbed by collecting ducts Free water clearance positive

ADH high and effect of free water clearance

All free water reabsorbed by late distal tubule and CD Free water clearance is negative

Normal body pH

7.4

Normal range of arterial pH

7.37-7.42

Ph range compatible with life

6.8 to 8

___ important as buffer in tubular fluid of kidney and intracellular buffer

Phosphate buffer

All enzyme systems and body functions are altered by

H concentration

Acidosis

Suppresses neuronal excitability —> coma

Alkalosis

Excessive neuronal excitability —> convulsions

3 mechanisms to maintain pH

``` Buffering (immediate) Respiratory compensation (rapid) Renal compensation (slower) ```

Acidosis if blood>>>

< 7.37

Alkalosis if pH of blood...

> 7.42

H secretion and HCO3 reabsorption occur in all parts of tubule except

TAL and TDL of loop of henle

Most HCO3 reabsorption occurs in

Proximal tubule

3 buffering systems

Bicarbonate Phosphate Proteins

Powerful intracellular buffers

Proteins

Most powerful regulators of pH

Kidneys

Kidneys regulate ECF H concentration by 3 mechanisms

Secretion of H Reabsorption of filtered HCO3 Production of new HCO3

Secretion of H by secondary active transport occurs in

PT TS of AL Early DT

H is combined with buffers in tubular fluid, and 2 main buffers

Phosphate | Ammonia

Normal P co2

Acidosis due to increase in PCO2

Respiratory acidosis

Acidosis due to fall in HCO3

Metabolic acidosis

2 forms of acid on body

Volatile | Fixed

Example of volatile acid

CO2

Examples of fixed acids

Sulfuric acid | Phosphoric acid

Kidneys play 2 major roles in maintenance of normal acid base balance

Reabsortion of HCO3 Excretion of fixed H