Pathophysiology: Renal Function

-maintain fluid/ electrolyte conversion and acid base balance

-detoxify and eliminate waste

-regulates vitamin D and calcium

-regulates blood pressure

-aids in RBC production

what are the 5 vital functions of the kidneys

> 1700 L

___ L of blood are processed via kidneys each day

1.5L

about ___ L of urine are produced by the kidneys daily

1-2

ONLY ___ L are excreted as urine each day; 99% is reabsorbed

20-25

renal function requires ___% of cardiac output

1000 - 1300

the kidneys are perfused with ___ ml of blood each minute

medulla

during instances of decreased blood flow to kidneys, blood is dispersed towards the ___ and away from the cortex

-renal artery

-renal veins

-subdivisions form afferent arteries

-other subdivisions supply blood to tubular structures

what does the renal receive blood supply from

Nephron

what is the functional unit of the kidney

-glomerulus

-tubular components

what 2 things is the nephrons composed of

filtration

the glomerulus is the site of ___

Bowman's capsule

cup-shaped structure of the nephron of a kidney which encloses the glomerulus and which filtration takes place. it is a clump of capillaries enclosed in a capsule called ___

high

the glomerulus is a ___ pressure system

H2O soluble nutrients, waste, and other particles

what 3 things are filtered at the glomerulus?

-endothelial layer

-basement membrane : SELECTIVELY PERMEABLE

-single celled epithelial layer

the glomerulus has a capillary membrane that contains what 3 things

-site of selectively reabsorption of substances

-site of selective excretion of substances

-proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting tubule

-filtration passes through each segment

what are the 4 section of the tubular component of the Nephron

4.6-8.0

Urine is clear/ yellow/ amber in color and has a pH of ___

bacteria

the pH in urine is more acidic to protect against ___

plasma

during the glomerular filtration rate, we are measuring the rate of filtration of ___

-colloidal osmotic pressure

-capillary filtration pressure

-capillary permeability

Glomerular filtration utilizes the same processes as the rest of the body in term of fluid movement such as:

proteins

the chemical composition of Glomerular filtration is similar to the of plasma EXCEPT it contains no ___

capillary basement wall

Glomerular filtrate has essentially same components as plasma, except it contains NO proteins, large molecules cannot readily cross the ___

perfusion pressure [renal blood flow]

Glomerular Filtrate is directly related to ___ of the glomerular capillaries

~125 ml/min

Glomerular Filtration Rate (GFR) = rate of filtrate formed each minute ___

renal blood flow

GFR correlates with perfusion pressure and ___

-Afferent constriction = decreased blood flow, GFR, urine output

-Efferent constriction = increased glomerular pressure and GFR [increased resistance to outflow]

Capillary filtration pressure of glomerulus is regulated by:

tubular segments

Filtrate travels to ___ from Bowman's Capsule

-proximal tubule

-loop of henle

-Distal & Collecting Tubules

what are the 3 sites of reabsorption or secretion

Proximal Tubule

___ is the site of MOST reabsorption & secretion - 65%

Glucose, amino acids, lactate, H2O soluble vitamins, Na, K, Cl, HCO3

what is being reabsorbed at the proximal tubule

H2O

the proximal tubule is highly permeable to ___

Na and H2o

the proximal tubule reabsorbs ___ and ___ equally

concentration of urine

the loop of Henle plays a role in controlling what

ADH hormone

___ exerts its affects at the loop of Henle site

Na and Cl

the loop of Henle reabsorbs more ___ and ___ than H2O

dilute

filtrate becomes more and more ___ as it travels through the ascending loop

H2O

the distal and collecting tubules are impermeable to ___

NaCl

10%

___ re absorption continues at the distal and collecting tubules at approximately ___%

K

Distal and Collecting tubules regulates the excretion of ___

H+

HCO3

at the Distal and Collecting Tubules, ___ is secreted and ___ is reabsorbed

Maintain perfusion necessary for GFR in order to remove waste product from blood

what is the goal of regulation of renal blood flow

-vasoconstriction

-vasodilators

what are the neural and humoral control mechanisms during the regulation of renal blood flow

-sympathetic nervous system (SNS)

-Angiotensin II

-Antidiuretic Hormone (ADH)

-endothelins

what 4 things are released during vasoconstriction?

-Dopamine

-Nitric oxide

-Prostaglandins

what 3 things are released during vasodilators

autoregulatory mechanisms

___ is geared at maintaining a constant flow of blood to the kidneys

Blood Pressure

auto regulatory mechanism only works when ___ is within a certain range

-senses a change in GFR with renal perfusion

-senses stretch of afferent arterioles- there by monitoring systemic B/P

-monitors NaCl concentration in tubular filtrates

what 3 things does the Juxtaglomerular complex do?

renin

___ is secreted in response to decreased renal perfusion

Renal clearance

___ is the volume of plasma that is completely cleared each minute of any substances that find its way into the urine

1. ability of a substance to be filtered in the glomerulus

2. ability of tubules to reabsorb or secrete the substance

renal clearance is determined by what 2 things

0

the glucose renal clearance rate = ___

-GFR

-Aldosterone

-Atrial Natriuretic Peptide (ANP)

what 3 things regulate the elimination of Na and K

Na and water

K

aldosterone promotes the reabsorption of ___ and ___ and the elimination of ___

functional

GFR is the best estimate of ___ renal tissue

1981

atrial natriuretic peptide (ANP) was discovered in ___

atria

atrial natriuretic peptide (ANP) is located in the ___ of the heart

vasodialation

atrial natriuretic peptide (ANP) causes ___ of afferent and efferent arterioles

Na

atrial natriuretic peptide (ANP) inhibits ___ reabsorption

ADH

pituitary glad

atrial natriuretic peptide (ANP) inhibits ___ release from the posterior ___

urine

atrial natriuretic peptide (ANP) increases ___ output

pH

the kidneys play a key role in regulating ___

H+

HCO3- (bicarbonate)

the kidneys eliminate ___ and reabsorb ___

7.35 - 7.45

the goal of the kidneys is to keep the pH balance between ___

purine metabolism

Uric acid is a product of ___

gout (hyperuremia)

excess levels of uric acid in the blood can cause ___

urine

excess levels of uric acid in the ___ can cause stones to form in the urine

urea metabolism

___ is the end product of protein metabolism

25 - 30 gm/day

an adult generates ___ gm/day of urea; quatities vary depending on protein in the diet, tissue break down, and GI bleed

kidneys

___ regulate the levels of urea in the blood stream (blood urea nitrogen = BUN)

glomeruli

tubules

urea is filtered in the ___ and reabsorbed in the ___

8 - 25 mg/dL

normal BUN levels are ___

dehydration

increased levels of BUN are seen in ___

-protein intake

-tissue break down

-fluid volume

-GI bleed

BUN depends on what 4 things?

kidney or liver

all drugs have to be metabolized either by the ___ or ___

urine

most drugs are eliminated in the ___ after being metabolized

lipid soluble

___ drugs are easily reabsorbed in the bloodstream

water

the goal is to convert lipid soluble drugs to ___ soluble and to eliminate

Vitamin D

___ maintains Ca+ balance in the body

erythropoietin/ stimulated by hypoxia

___ stimulates the production of RBC's

RAAS (renin-angiotensin-aldosterone system)

___ maintains blood pressure and fluid balance

-BUN

-creatinine

-electrolytes

-uric acid

-pH

-RBC's

-GFR

what are the 7 different types of blood test

0.6 - 1.2 mg/dL

what is the range of creatinine levels

Creatinine

___ is most specific to the kidneys and is a by product of protein breakdown

creatinine

which is the better blood indicator between BUN and Creatinine?

95%

___% of creatinine is filtered out of the body

renal problem

when levels of creatinine exceed normal limits, this indicates a ___ problem

BUN/Cre

the two test of BUN and Creatinine when put together are called ___

GFR

___ is the BEST indicator of renal function

obstructive disorder

___ is something that physically blocks the flow of urine from the kidneys

age

Obstructive disorder can occur at any ___ and affect any level of GU system

reversible

most obstructions are ___ and require prompt intervention

Bilateral acute UT

___ obstructions may lead to acute renal failure

atrophy and renal failure

untreated obstructive disorders lead to ___ and ___ if bilateral

-developmental defects

-pregnancy

-enlarge prostate known as benign prostate

-tumors

-stone

-scar tissue

-neurologic dysfuction

what are the 7 causes of obstructive disorders

Lower obstructive disorder

___ is below ureterovesical junction and are bilateral (both kidneys are affected)

upper tract obstruction

___ is below ureterovesical junction and are unilateral (one kidneys is affected)

-upper tract obstruction

-lower tract obstruction

what are the 2 classifications of obstructive disorders

-degree

-duration (chronic or acute)

the damage of obstructive disorders depends on what 2 things

-stasis (urine stays in one place) and may lead to infection and/or stone formation

-dilation of renal structures

what are the 2 mechanisms of renal damage

hydronephrosis

___ occurs when there is urine filled dilatation of the renal pelvis and calices