SF: Chapter 26pt4

Aquaporins are also called

water channels

Aquaporins def.

membrane proteins that form holes in a membrane

function of aquaporins

move water across cell membranes in response to osmotic gradient created by active solute transport

aquaporins increase or decrease permeability?

increase

Where do we find aquaporin

DCT and Collecting duct for water

Overhydrated does what to ADH

ADH production decreases

Overhydrated does what to osmolality

falls to 100 mOsm

Overhydration causes a decrease in?

number of open aquaporins in the collecting duct which decreases water reabsorption

While overhydrated, what type of urine is excreted

large quantity of dilute urine excreted (diuresis)

How much urine is excreted when overhydrated

20-30L/day

When dehydrated, what is happening to ADH

released by posterior pituitary in large quantities

When dehydrated, what is happening to solute concentration of urine

rises to 1200 mOsm

When dehydrated, what is happening to number of aquaporin channels in CD

increase and remain open, increasing permeability to water

What percentage of water in filtrates is reabsorbed into the blood when dehydrated

99%

Why do we reabsorb so much water when we are dehydrated

allows us to survive without water or when water is sparse

How much urine is excreted a day when dehydrated?

1/2L of very concentrated urine

Diuretics def.

chemicals that increase rate of urinary production/output

Alcohol causes diuresis. How?

by inhibiting ADH secretion

How do diuretics work?

increase urine flow by inhibiting sodium, then reabsorbing water

ex of diuretics/things that cause diuresis

anti-HTN, CHF edema, cirrhosis of liver, diet pills, caffeine

why is caffeine a diuretic

because it is a vasoconstrictor

Loop diuretics med ex

furosemide (lasix)

how do loop diuretics work

potent, inhibit the medullary gradient in the ascending loop of henle

how do thiazides work

less potent, act on the DCT

Osmotic diuretics: function

carry water out with substance (BS)

Complications from using diuretics

dehydration and electrolyte imbalances

Urine removes?

<1% of filtrate

What does filtrate lose when becoming urine

water, nutrients, ions, amino acids, and glucose

What does filtrate gain in excess when becoming urine

nitrogenous waste products, toxins, and drugs

How does urine typically present

clear, yellow to amber, aromatic, and slightly acidic

When do we see urochrome pigment with urine?

Hgb destruction

As urine increases in concentration, what happens to its color?

becomes darker

What can cause urine to appear darker?

different foods, bile pigments/blood in the urine, meds or vitamins

What could cause cloudy urine

infection/UTI

Why does an infection cause urine to smell stronger?

bacteria metabolism created ammonia smell

What uncontrolled condition/disease causes a fruity acetone smell

diabetes mellitus

What is mostly found in urine

water

What is found in higher amounts in urine, urea or ions

urea

When there is very high concentrations of solutes, or when there are abnormal substances are present, what do we suspect?

this is pathology for DM

What types of solutes can we find in high concentrations in the urine when abnormal

blood cells, bile pigments, plasma proteins

What is urine pH

slightly acidic, 6

When there are changes in body metabolism or diet, how does urine pH change

4.5-8

What types of foods are eaten in an acidic diet

high protein intakes and whole wheat products

What type of foods are eaten in an alkaline diet

vegetarian intake

What can cause alkaline urine that isn't diet

bacterial infection in urinary tract

What is specific gravity

ratio of mass of substance to mass of equal volume of distilled water

What is the specific gravity of water

1.0

What is the specific gravity of variable solute concentrations

1.001 - 1.035

What causes a high specific gravity

dehydration, pyelonephritis

What causes a low specific gravity

dilute urine, thirsty, renal damage

How do we measure specific gravity

hydrometer

What is the role of the ureters

move urine via peristalsis from kidney to bladder

urinary bladder def.

hollow, muscular, urine storage site

How much can the urinary bladder store

500-1000mL

in males, what is the position of the urinary bladder

anterior to rectum

in females, what is the position of the urinary bladder

anterior to vagina

What structure is seen in the urinary bladder that we can also find in the stomach

rugae (important for stretch)

What is the area of the bladder where the ureters enter and urethra exits

trigone

does the trigone area expand as the bladder fills?

no. acts as a funnet

What cell type is found in the urinary bladder

transitional epithelium

How do cells appear in the first layer of the bladder

binucleate and domed

What muscle is found at the bladder that forces urine out

detrusor muscle

Cystitis def.

inflammation of the bladder due to bacterial infection

What specific pathogen typically causes cystitis

e.coli

urethra function

transports urine out of body

internal urethral sphincter muscle type

smooth muscle

internal urethral sphincter function

prevents urine leakage from bladder

internal urethral sphincter: male specific function

contracts to keep semen from entering urinary bladder during sex

internal urethral sphincter: female specific function

prevents urine leakage

external urethra sphincter muscle type

skeletal muscle

external urethra sphincter function

voluntary control of urine passage

What is the difference between the male and female urethra

length

Do males or females have a shorter urethra

females

what are the 3 important male parts related to the urethra

prostatic urethra, membranous urethra, and spongy urethra

What is important to know about bladder cancer detection

need to ID early BEFORE it penetrates the muscle wall

if bladder cancer detection is done early, what is the 5 year survival rate

77%

What percentage of bladder cancer cases are caused by smoking

50%

What percentage of bladder cancer cases are caused by environmental carcinogens (ex: hair dye)

30%

What is the remaining percentage of bladder cancer cases caused by?

combo of factors; heavy drinking and smoking

In 80-90% of bladder cancer cases, what is the 1st sign

hematuria and change in urinary frequency

How to ID bladder cancer

cystoscopy

How to treat bladder cancer

transurethral resection of bladder tumor, immunotherapy with intravesicular delivery of BCG (TB vaccine)

How to treat a severe bladder cancer

neobladder

micturition def.

act of urinating/void of empty bladder

micturition is the ____ flow from ??

constant flow from kidney to bladder

When urine reaches >200mL, what happens in the bladder

stretch receptors are maxed and we cannot control our urge to pee

What else can cause an increased urge to pee

irritation of bladder/UTI

What are 3 factors that control distention

1. wall of urinary bladder contains large folds

2. transitional et distends

3. smooth muscle wall of bladder can stretch and urine enters

In micturition, how much urine can remain

10mL

what can help strengthen our bladders

Kegel's exercises

Are men or women able to completely void?

women due to gravity

What do men depend on to completely void

bulbospongiosus muscle

incontinence def.

inability to control urination or defecation

Who tends to be incontinent

infants, pregnant persons, elderly

What situations can cause incontinence

emotional, stress, coughing, laughing, NS problem

Stress incontinence def.

sudden increase in intra-abdominal pressure forces urine out

Who is stress incontinence common in

pregnant people

urge incontinence def.

strong urge to go with sudden onset and some leakage

What can cause urge incontinence

bladder cancer, inflammation, infection/stones

What is required to fix urge incontinence

bladder retraining