Urination Test Review

What are the four functions of the urinary system?

-Excrete metabolic waste

-Maintain water salt balance

-Maintain acid-base substance

-Secretes hormones

What are the three nitrogeous waste? How are they made?

Urea: byproduct of amino acid metabolism

Creatinine: byproduct of creatinine phosphate breakdown

Uric Acid: byproduct of breakdown of nucleotides

How is water salt balance maintained?

Blood volume associated with salt balance

Salt causes osmosis into the blood; the more water, the higher the blood pressure.

The kidney plays a role in blood pressure regulation through water and salt regulation

How is acid base balance maintained?

It is maintained through the excretion of hydrogen ions and re-absorbtion of bicarbonate

What are the two major hormones in the system? What do they do?

Renin: leads to aldosterone release from adrenals which causes re-absorbtion of sodium ions

Erythropoeitin: stimulates red blood cell production and activats vitamin D for calcium absorbtion

Kidney where tf the function???

-Located in lumbar regions

-posterior to serous membrane

-covered in a tough capsule

-concave side called hilus

Ureters

Conduct urine from the kidney to bladderthe

-3 Layers mucosa, skeletal muscle, smooth muscle

Where are the two spincters that control when you pee?

Internal sphincter in the smooth muscle involuntary control

External sphincter in skeletal muscle controls voluntary control

Urethra

-Conducts urine out of the body

-Women 2in UTI risk

-Men long bc same route as reproduction

How do we sense the need for urination?

1) Stretch receptors in the walls of bladder signal when filled to 250

2) inpulses from spinal cord causes bladder to contract and pee

-Reflex can be overidden by brain

Glomerular Muscle (Bowmans)

Cupcake like structure

-inner layer has podocytes

-specialize cells cline into glomerular capillaries

-forms pores passage of small molucules

PCT

Cuboidal epithilial cells with microvilli and extend to medulla

Loop of Henle

U shaped

-simply squamous epithelium

-extends to medulla

DCT

Cuboidal epithelial cells with no microvilli

-DCT’s of several nephrons enter collecting duct

-Collecting duct empty out into renal pelvis \

Collecting Ducts

Empty into renal pelvis

-final part of nephron

-collects urine from multiple nephrons

-Further adjust water salt balance

and concentrate urine before it exits the kidney.

Renal artery

Brings blood to kidney

-in nephrone it branches into smaller arterious that supply blood to glomerulus

Glomerulus

-capillary ball in bowman

-filter blood by letting water, ions, and small molecules to pass into the nephron

-large molecules like protein and blood cells stay in the blood

What glomerulus remove?

-blood that enters high pressure

-water, nitrous waste, salt ions are filtered while blood cells and plasma proteins stay

What is reabsorbed into the blood stream?

80% of what is filtered is reabsorbed in the PCT

Reabsorbed: water, nutrients, and salts

Not reabsorbed: some water, waste, excess salts

What percentage of sodium is reabsorbed by the kidneys?

99% of the sodium filtered is reabsorbed.

Where is sodium primarily reabsorbed?

- 67% in the Proximal Convoluted Tubule (PCT).

• 28% by the ascending limb of the loop of Henle.

  • The remainder by the Distal Convoluted Tubule (DCT) and collecting duct.

How is a solute gradient established in the Loop of Henle?

The Loop of Henle has two parts:

• Salt diffuses out of the lower part of the ascending limb.

• The upper part of the ascending limb actively transports more salt out.

  • This creates high osmotic pressure in the medullary tissue.Water is reabsorbed from the descending limb.

What happens to water reabsorption in the kidneys?

Water leaves the DCT due to a gradient.

• Water also leaves the descending limb of the loop of Henle.

• As filtrate enters the collecting duct, it is isotonic to the renal cortex cells.

• As filtrate passes down the collecting duct, it encounters a high osmotic gradient.

• The permeability of the collecting duct is under hormonal control.

Glomerular Capsule

-Cupcake-like structure

-Inner layer containing podocytes

-Specialized cells cling to glomerular capillaries

-Form pores for the passage of small molecules to filter blood and form urine.

What are diuretics and how do they work?

Substances that increases flow of urine

Alcohol: Shuts of ADH, dehydration causes hangover.

Caffeine: Increases glomerular filtration, decreasing tubular reabsorption of sodium

Drugs: Many inhibit active transport of sodium at loop of Henle or DCT

Illnesses of the urinary tract and what they do?

Urethritis: inflammation of urethra

Cystitis: inflammation of bladder

Kidney Stones: UTI, large prostate, pH imbalance, ingestion of too much calcium. All cause predispose kidney stones

What is Hemodialysis?

Artificial kidney machine, or continuous ambulatory peritoneal dialysis.

How successful are kidney transplants?

97% if its from a direct relative.

What is the kidneys fuction in pH regulation?

• Only acids can remove many acids and bases

• Slower acting then respiratory system but more powerful

• Reabsorbs bicarbonate ions

• Excretes hydrogen ions

• In urine, ammonia can absorb hydrogen ions, phosphate can do this as well