X Smester2 Phys Ii Test 1

Front 1

As an excretory function of the kidney the body is required to eliminate a minimum of______ as metabolic waste

Back 1

500 mL a day or .5L a day

Front 2

The kidney has three endocrine functions which are:

Back 2

1. secretion of erythropoietin
2. secretion of renin
3. conversion of vitamin D to its active form

Front 3

Secretion of erythropoietin leads to the

Back 3

stimulation of RBC production in response to hypoxia

Front 4

Two major regions of the kidney

Back 4

1. Renal Cortex
2. Renal Medulla

Front 5

Blood Supply to the kidney

Back 5

1. renal artery
2. afferent arteriole
3. glomerulus (network of glomerular capillaries)
4. efferent arteriole
5. peritubular capillaries
- water and solutes reabsorbed from the proximal tubule fluid into the interstitium are returned to circulation through the peritubular capilarries
6. renal vein
7. two capillary systems

Front 6

Two Capillary Systems:

Back 6

1. glomerular capillaries
2. peritubular capillaries

Front 7

Glomerular capillaries

Back 7

High hydrostatic pressure
Rapid fluid filtration
Contained bt two resistance vessels
- afferent arteriole
-efferent arteriole

Front 8

What is the sole function of the two resistant vessels?

Back 8

To provide a high pressure for glomerular filtration

Front 9

Peritubular capillaries

Back 9

Lower hydrostatic pressure
Rapid reabsorption of solutes and fluid from the interstitium

Front 10

Characteristics of nephrons:

Back 10

Cannot be regenerated
Gradual decrease in number with aging

Front 11

Two major components of the nephron:

Back 11

Glomerulus
Tubule

Front 12

Glomerulus:

Back 12

Network of glomerular capillaries through which fluid and solutes are filtered from the plasma.

Front 13

In the glomerulus, how much of the incoming plasma flow from the afferent arteriole is actually filtered

Back 13

20% or (filtration fraction of .2)

Front 14

The glomerulus is ______ and the first portion is called the _____.

Back 14

coritcal, Bowman's capsule

Front 15

Fluid filtered at the glomerulus flows into the _____________. It then enters the next segment called the _____________ which is also _________.

Back 15

Bowman's capsule.
Proximal tubule, cortical

Front 16

After the proximal tubule is the ________________.

Back 16

Loop of Henle

Front 17

The Loop of Henle has two types of loops

Back 17

1. Cortical
2. Medullary (20% of nephrons)

Front 18

Three segments of the loop of henle:

Back 18

1. Thin descending limb
2. Thin ascending limb
3. Thick ascending limb

Front 19

Macula Densa

Back 19

short tubular segment which lies at the end of the thick ascending limb and at the beginning of the next tubular segment (distal tubule)

Front 20

combined structural association (roughly, a triangular region) of the macula densa cells, the afferent arteriole, and the efferent arteriole forms

Back 20

juxtaglomerular apparatus or complex

Front 21

Where are the sites of renin secretion?

Back 21

Juxtaglomerular apparatus (JG)

Front 22

The last two portions of the nephron consists of

Back 22

The distal tubule (cortex) and medullary collecting duct.

Front 23

Two types of nephons:

Back 23

Cortical nephrons
Juxtamedullary nephrons

Front 24

loops that either barely or may not penetrate into the medulla

Back 24

Cortical nephrons

Front 25

long efferent arterioles that extend into the medulla and which divide into the vasa recta capillaries that lie beside and along the juxtamedullary loops and then return to the cortex

Back 25

Juxtamedullary nephrons

Front 26

Renal Transport Processes:

Back 26

1. Glomerular filtration
2. Tubular reabsorption
3. Tubular secretion

Front 27

Glomerular Filtration is

Back 27

due to the high hydrostatic pressure in the capillaries, plasma water and solutes are filtered through the capillaries into Bowman’s capsule; normally, about 20% of the fluid entering the glomerulus is filtered (filtration fraction, FF = 0.2)

Front 28

Within glomerular filtration most substances are freely and nonselectively filtered, and solute concentrations in the glomerular filtrate are the same as in plasma EXCEPT for

Back 28

Albumin and RBCs

Front 29

GFR aka

Back 29

Glomerular Filtration Rate

Front 30

selective recapture of solutes and water from the PT fluid and their movement into the peritubular capillaries

Back 30

Tubular secretion

Front 31

Tubular Secretion:

Back 31

1. selective transfer of solutes from the peritubular capillaries into the tubular fluid
2. 80% of renal plasma flow that is not filtered flows through the peritubular capillaries

Front 32

Filter Load (mg/min)=

Back 32

GFR (mL/min) x plasma concentration (mg/mL)

Front 33

Af> Ae

Back 33

net reabsorption occured

Front 34

Af < Ae

Back 34

net secretion occured

Front 35

If something is filtered but neither reabsorbed not secreted,

Back 35

Renal clearance= GFR
Ex: creatine

** LOOK at notes for Scenarios**

Front 36

the renal clearance of creatinine (termed the creatinine clearance, Clcr) to be used as a reasonable estimate of

Back 36

GFR

Front 37

filtered and partly reabsorbed but not secreted

Back 37

Renal clearance < GFR

Front 38

1. filtered and completely reabsorbed and not secrete

Back 38

Renal clearance = 0

Front 39

filtered, not reabsorbed, and secreted

Back 39

renal clearance > GFR

Front 40

Excretion =

Back 40

Filtration + Secretion - Reabsorption

Front 41

Three Layers of the Glomerular Membrane

Back 41

1. endothelium of the glomerular capillary wall
2. basement membrane between the glomerular endothelium and visceral epithelium of Bowman’s capsule
3. epithelium from the inner layer of Bowman’s capsule

Front 42

Endothelium layer Characteristics :

Back 42

- perforated by thousands of pores (fenestrae) which are large enough to allow passage of albumin
-- permeability of these capillaries is about 100 times greater than any other capillary system in the body

Front 43

Basement Membrane

Back 43

- proteoglycans (glycoproteins) have strong negative charges which repel plasma proteins and prevent their filtration; primary restriction on filtration of plasma proteins

Front 44

Composition of the glomerular filtrate:

Back 44

1. Glomerular membranes are impermeable to albumin
2. Concentrations of all other aolutes not bound to plasma proteins are the same as in the plasma

Front 45

Filtration characteristics of glomerular capillaries

Back 45

-very high hydrostatic pressure
-very large surface area
-very high permeability except for very high MW substances
-highly negative charged substances are repelled by the basement membrane

Front 46

Two major difference of Glomerular filtration versus other capillary systems:

Back 46

1. Net filtration pressure over the whole length of the glomerular capillary (both aff and eff arteriorles are high pressure reistance vessels)
2. Glomerular capillaries are much more permeable than systemic capillaries

Front 47

Forces of Glomerular Filtration:

Back 47

1. glomerular capillary hydrostatic pressure (Pg)
2. Bowman’s capsule hydrostatic pressure (Pb)
3. colloid osmotic pressure of proteins in glomerular capillaries (πg)
4. protein-free filtrate that enters Bowman’s capsule exerts no colloid osmotic pressure

Front 48

promotes filtration and increases GFR

Back 48

glomerular capillary hydrostatic pressure (Pg):

Front 49

): opposes filtration and decreases GFR; normally, Pb << Pg

Back 49

Bowman’s capsule hydrostatic pressure (Pb

Front 50

opposes filtration

Back 50

colloid osmotic pressure of proteins in glomerular capillaries (πg):