Renal System Anatomy and Physiology

Kidneys, Ureters, Bladder

- Inside of our kidneys are MILLIONS of NEPHRONS* that filter out our waste

Osmolarity

Number of solutes to water in LITERS

Osmolality

Number of solutes to water using weight (KG)
--> Concentration of blood or urine
--> Ex ; Salt crystals in water
--> Think of it like particles floating in fluid
--> Osmosis - used to dilute HIGH concentrations
of solute

Tonicity

- Isotonic
- Hypotonic
- Hypertonic

Isotonic

- Equal to normal osmolarity
- Ex ; Normal Saline, Lactated Ringers
--> Trying to give person VOLUME
- Anything EQUAL to 0.9

Hypotonic

- LESS molecules and MORE water
- LOW number of particles in the water (HYPO)
--> The water goes into the cells and SWELLS
- Like a HIPPO
- Diluted
- Ex ; like a SWOLLEN RBC
- Any fluid LESS than 0.9%
- We wouldn't give a HYPOTONIC solution to someone
with CEREBRAL ATROPHY

Hypertonic

- MORE molecules and LESS water
- HIGHER number of particles out in the water and
LESS WATER
--> Leads to DEHYDRATION of the cell ; will shrink
and shrivel
- Concentrated
- Ex ; like a shrunken (crenated) RBC
- Anything above 0.9% is HYPERTONIC

- 2.2 pounds
- mL or 1 L

1 Kg = ___ pounds
1 Kg = 1,000 ___ or ___ L

Healthy Kidney Function

- Filter - helps us with SODIUM and WATER removal
- Waste Removal
--> Protein - albumin-urea (waste product of
protein metabolism)
--> Creatinine - waste product - specific indicator
of kidney problems
--> Waste product of muscle breakdown
--> If we find this in HIGH levels, this
indicates a kidney issue - BEST
INDICATOR

Albumin

-Protein-Albumin-Urea
- Waste product of *Protein Metabolism*

Creatinine

- Waste product of *Muscle Breakdown*
- Specific indicator of Kidney Problems
- If we find this in HIGH levels, this indicates a Kidney
issue - best indicator*

Hormone Production

- Renin
- Erythropoietin

Renin

- Released due to DROP in blood pressure
- Will release Renin* if the kidneys DO NOT have GOOD perfusion

Erythropoietin

- Stimulate RBC production
- CKD - related to anemia

Unhealthy Kidneys

- Elevated Waste -
- HIGH - urea, creatinine, potassium , magnesium,
phosphorus

Aging Considerations - Renal System

- Kidney weight and volume decreases
- Renal blood flow decreases
--> From atherosclerosis
--> Can happen at the glomerulus
- Vascular changes
--> Thickening of renal arteries and sclerosis of
glomerulus
- Nephron
--> Yearly decline in number
- Tubules
--> Degenerated and shortened
- Bladder
--> Reduced tone, capacity, urinary incontinence in
WOMEN* - from dec. estrogen affecting the
urethral sphincter
- Prostate Enlargement
- Decreased muscle mass
- Decreased Vitamin D synthesis
--> LOW calcium levels (due to high phosphorus*
levels - inverse relationship)
--> LOW calcium = unable to absorb Vitamin D

Glomerular Function

- Measurement of Kidney Function
- Volume of plasma filtered at the glomerulus into the
kidney tubules EACH MINUTE*
- normal rate - 120 ml/min
- Sensitive indicator ; the BUN and Creatinine will
ELEVATE - not excreting like it SHOULD
- Decreased GFR = Kidneys are NOT functioning well
- Anything above 90-120 is NORMAL
- 90-15 indicates = Kidney Disease
- Anything LESS than 15 indicates Kidney Failure
- These people need dialysis - nephrons are DYING
and glomerulus is NOT functioning well

Glomerular Function

- 90-120 - Normal
- 15-<90 - Kidney Disease
- <15 - Kidney Failure