overview of kidney functions

• Maintain ___ balance in the body
• maintain proper ___ of body fluids
• regulate the quantity and concentration of most ___ ions
• maintain proper ___-___ balance & ______ volume
• eliminating wastes of bodily metabolism, esp. ___
• excreting ___ compounds
• producing e_______ & r_____
• converting ______ into its active form

• H20
• osmolarity
• ECF
• acid-base, plasma
• urea
• foreign
• erythropoietin and renin
• vitamin D

Gross anatomy

• _____ is the outer layer of the kidney
• ____is the inner layer of the kidney

• cortex
• medulla

the functional unit of the kidney is the _____

• there are millions of them per kidney
• it is a microscopic tubule system arranged within the cortex and medulla
• they are the urine producing units of the kidney

the ____ _____ is where the urine collects in the kidney

• urine drains out of the nephron tubules, collects here, and then drains down into the ureter to be stored in the bladder

each nephron has a ____ system and _____ component

• each nephron has its own capillary bed

____ is a specialized capillary bed that will filter the blood that will potentially create urine

• there are about 1 million of them, one for each nephron

vascular system and tubular component

glomerulus

urine starts as ____ which is filtered blood

capillary bed does filtering

we don't filter ______, they are left in the blood

filtrate

proteins

______ pressure drives fluid back into the capillary bed

how much potential urine is created in a single day across the capillary bed?

how much urine do you typically excrete in a day?

osmotic P

180 L/day

~1L/day

the _____ filters large volumes of protein-free plasma into the tubular component

the ______ _____ nourish the renal tissue and participate in exchanges b/t the tubular fluid and plasma

glomerulus

peritubular capillaries

what determines what gets filtered out of the glomerulus?

what doesn't get in?

nutrients, glucose, amino acids, etc. could potentially end up in the urine but aren't because they are _____

the size of the substance

proteins

reabsorbed

a large amount of reabsorption takes place at the _____ convoluted tubule

the cells found here have microvilli in apical membrane and have highly infolded _____ membrane (along the basolateral membrane)

proximal

plasma

blood;filtrate

microvilli are in contact with the filtrate inside the tubule system

the cells found in the region of the proximal convoluted tubule are the ____ _____ ____ ____

they have microvilli, mitochondria, and a highly infolded plasma membrane

the cells found in the region of the ascending and descending loop of henle are called the ___ _ ___(thin-segment) ___

distal convoluted tubule cells

Glomerular filtration is based on the ___ of the substance

everything but protein gets through

(a little bit sometimes passes thru)

the protein that does pass is ____

the bulk flow across the capillary bed created in a day _____L

size

albumin

180

______ ______ is the movement of a substance from the filtrate back into the blood (plasma)

if you are reabsorbing something, your body wants to ______ it in the body

99% of most things get ____

keep

reabsorbed

____ of a substance is moving from the plasma into the filtrate

this is the second chance to get rid of a substance..

the first chance is through filtration

secretion

what are the 2 most common things secreted?

after tubular secretion you have _____

potassium and hydrogen

excretion

renal blood flow is appx. __-__% of cardiac output

• is how much blood flows into your kidneys each minute

~appx. _____ml/min.

20-25

1200

the kidney is filtering the ____ in the blood

renal plasma flow is ~____ml/min.

plasma

625

glomerular filtration rate (GFR) is ~___-___ml/min.

about 180 L/day

what is the urine flow rate?

Urine flow rate is ~ _ml/min.

what is urine production?

urine production is ~ __-__L/day

the range is 0.5-10 L/day

urine flow rate-how much urine is made each minute

1ml/min

urine production-how much urine is made throughout the day

1.0-1.5 L/day

under normal circumstances the kidneys are working at the lower end of urine production because they reabsorb most of the ___

the hormone that changes the amount of urine output is ____ or ___

h20

vasopressin or ADH(antidiuretic hormone)

there are nephron subtypes

some have long loops of henle and some have small ones

the _____ nephron is the long-looped nephron important in establishing the medullary vertical osmotic gradient (__% this type)

the ____ nephron is the most abundant type of nephron and they are mainly in cortex(__% this type)

juxtamedullary

20%

cortical

80%

the juxtamedullary nephrons are involved with the _____ of water

the cortical nephrons are involved in ____

conservation

reabsorption

by the time filtrate gets to the end of

the proximal convoluted tubule located in the cortex, most all of the nutrients should be _______

this is the one place where the same amount of ___ and ___ get reabsorbed together.

they seperate out after this point.

~67% occurs here

reabsorbed

water and salt

cortex

outer medulla

• is located in the cortex
• reabsorbs 100% nutrients
• _7% of water/salts
• 5_% of urea

reabsorbs the nutrients and puts them back into the blood

proximal convoluted tubule

67%

50%

• located in the inner medulla
• reabsorbs _5% of water

thin descending limb

15%

• located in the outer medulla
• reabsorbs _5% of salt

thick ascending limb

25%

• located in the cortex
• reabsorbs _% salt
• 0% __
• secretes K+ and H+

any remaining salt is reabsorbed in the end of this area. it is controlled by ______

distal tubule

5%

water

aldosterone

• located in the cortex
• reabsorbs _% of salt
• reabsorption is controlled by aldosterone
• _% water

distal tubule...near very end before cortical collecting tubule

3%

0%

• located in the inner medulla
• reabsorbs _-__% water
• controlled by ADH

not all water is reabsorbed b/c you need to have some fluid to be excreted as urine

the area b/t the outer medullary collecting duct and the inner medullary collecting duct

8-17%

nitrogen comes from proteins, amino acids, rna, dna, etc.

nitrogen is toxic, body has to get rid of it

___ is a nitrogen waste product

(when it sits for a long time it will turn into ammonia..smells bad..why old diapers will smell worse after sitting for a while)

nitrogen is removed from the body as ___

how much urine is produced depends on the levels of __ in the collecting duct (b/t the outer and inner medullary collecting ducts)

urea

ADH

there is a _____ rate of exchange at the capillary beds of the glomerular compared to other capillary beds

these capillaries have a high permeability and BP

BP in a typical capillary bed~35mmHG

BP in the glom. ~ __-__ mmHG

greater

50-55

the BP across most capillary beds decrease, but the BP in the glomerular region is ____ across both ends

these capillary beds are leaky

glomerular filtration is the ___ step in making urine

constant

first

the ______ limb of the loop of henle of juxtamedullary nephrons are permeable to H20 and do not extrude NaCl

300

1200

the ________ limb of the loop of henle actively transports sodium chloride out of the tubule and into the interstitial fluid

-it is always impermeable to water, so salt leaves without water osmotically following along

ascending

200

the interstital fluid always achieves equilibrium with the ____ limb of the loop of henle

gradient is established in the medullary interstitial fluid

ascending

countercurrent multiplication