A&PII: urine

Function of the Urinary System

Is the kidney retroperitoneal?

Kidney slightly lower to the ____.

Kidney is about the size of a . . .

Renal hilum

–_vertical cleft

–Leads to ____
–Ureter, renal blood vessels, lymphatics and nerves enter here

Renal fascia-_____tissue and Anchors kidney and adrenal gland

_____- Surrounds the kidney and cushions it
_____ -Transparent, prevents infections from spreading to the kidney

Renal artery to _____, to interlobar, to _____, to cortical radiate, to _____, to _____>

Is there a segmental vien?

Nephrons form

Nephron

Parts

–glomerulus
A ball of capillaries

– renal tubule
glomerular capsule (Bowman’s capsule)

–Cup shaped end of the renal tubule

–Has fenestrated endothelium

–renal corpuscle
Glomerulus + Bowman’s capsule

Filtrate

–Solute rich fluid from the blood (no protein)

–Urine made from this

Bowman’s Capsule Structure

Parietal layer

–____ epithelium

–Not involved in forming ____

Visceral layer

–Clings to the _____
–Podicytes

Podicytes 

Highly branched modified epithelial cells
Foot processes intertwine and cling to the _____
Filtrations slits

–Spaces between the _____

–Allow filtrate to enter the capsular space

The rest of the renal tubule…

The rest of the renal tubule empties . . .

The rest of the renal tubule
three parts ?

Cortical nephrons

–85%

–Almost entirely in the ___.

–Part of ____ dips into the outer medulla

Juxtamedullary nephrons

–Concentrate ____

–Entire _____ is in the medulla

Two capillary beds

–Glomerulus
Specialized for ____
Afferent arteriole and efferent arteriole


–Peritubular Arise from the efferent arteiole Specialized for reabsorption . . .

Juxtamedullary Apparatus

Most distal part of the loop of Henle lies along the _____ (sometimes efferent too)

Juxtamedullary Apparatus


Two important cells types in the JMA

–____ cells
Aka juxtamedullary cells
Sense blood pressure and secrete ____
In the arteriole

–Macula densa
Chemoreceptors that sense NaCl in the filtrate

3 step urine production

Glomerular Filtration

Passive or Active jQuery11010013946590766312106_1493813961379??
Due to ____ pressure
Fluids and small solutes forced out of the glomerulus
Amazing filtration membrane
Filtration rate=120-125 ml/min

Glomerular Filtrate
Water
Ions–Sodium, potassium, chloride
Nitrogenous waste–Urea, uric acid, creatine
Organic molecules–Glucose, amino acids

Tubular Reabsorption

Most of the filtrate is quickly reabsorpted
Must cross the barrier formed by ______.

Tubular Reabsorption

Two reabsorption pathways

–Transcellular (through cells)
Through the ___ and/or ____
Most solutes are reabsorbed through this pathway by _____.

–Paracellular (between cells)
Through _____.
–Water and some ions use both

Blood Pressure is the driving force of glomerular filtration…what drives reabsorption?

Osmolarity of interstitium is increased
How-transport sodium into the interstitium?

____ is total concentration of all solute particles in a solution

Counter current mechanisms maintain osmotic gradient

Ascending and descending limbs of Loop of Henle interact to maintain _____.

Needed for urine _____.

Counter current mechanisms maintain osmotic gradient

Ascending limb

–Creates the conditions need for the descending to function

–Actively transports NaCl into interstitium

–Highest solute concentration near the bottom

–Impermeable to ____

Tubular secretetion

1. in reverse
2. Disposes of substances

–Certain drugs
3. Eliminates undesirable end products that were reabsorped passively

–i.e. urea
4. Rids excess ___
5. Controls ____

Descending limb

–Concentrates ___for ascending limb

–Filtrate concentrates to ___normal body fluid

Vasa Recta

How does the kidney retain the solutes?

–They would be absorbed by normal capillaries but are, why?

–They function as ____ exchangers

–Loops ____ nutrients and oxygen

–Then form ____ to go from increasing osmolarity back to decreasing.

Urine color and transparency 

–Clear, pale to deep yellow

–Yellow due to urochrome: Pigment by product of _____

–Pink, brown may be due to eating certain foods; may be due to presence of bile pigments or blood; Certain meds or vitamins

–Cloudy may indicate _____

Odor

–Fresh usually has little smell

–Develops an ammonia odor due to _____.

–Some drugs and foods alter odor
i.e. asparagus, brocholi

–Some diseases affect odor
i.e. diabetes mellitus fruity smell

pH

–Usually about 6

–Health and diet can affect pH

–Range____ normal

–Acidic- due to ____

–Alkaline- due to vegitarian

Compostion

95% water
Next is urea
other nitrogenous waste

–Uric acid, creatine
Solutes (in order of normal concentration most to least)

–Na+, K+, PO43-, SO42-, creatine, uric acid, Ca2+, Mg2+, HCO3-

Ureters- describe

Urinary Bladder

Collapsible muscular sac
Temporarily stores urine
Retroperitoneal
Trigone–Outlined by the three openings, area where infections “sit”–Ureters enter inferiorly--So a full bladder closes them off, prevents back flow–Urethra exits inferiorly
Detrusor muscle
Rugae

Bladder


Holds about ___ml of urine when moderately full

–Can hold about twice that much (800-1000 ml)

–Can burst if over extended
Due to blockage, you cannot hold it long enough to burst your bladder, your body won’t let you

Thin walled muscular tube Drains urine from the bladder

Urethra 

Internal urethral sphincter

–At bladder-urethral junction

–Involuntary or voluntary?

–Prevents leaking when not ___

–Contracts open and relaxes closed (weird right?)

External urethral sphincter

–Surrounds the ____ as it passes through the urogenital diaphram

–Voluntary or involuntary?

–Works with the levator ani

Female



–Bound to ____ vaginal wall

–External urethral orifice
Anterior to vaginal opening
___ to the clitoris

AKA urination, voiding
The act of emptying the urinary bladder

Micturition

3 thing must happen to allow micturition

–The ___ muscle must contract (open)
Involuntary

–The ___urethral sphincter must open
Involuntary

–The ____ urethral sphincter must open (relax)
Voluntary