Excretory System

Urinary system

Structures of the Urinary System

2 kidneys – produce urine, filter blood 180 L of blood per 24

hours filtered 2 ureters – tube that

leads to the bladder Bladder – stores urine Urethra – tube for

eliminating urine

Kidney Function

A. filter blood that has collected wastes from cells. B. Excrete waste – urea, uric acid, creatine,

ammonium C. Maintain blood volume – regulating water

excretion D. Monitor electrolytes in blood E. Monitor blood pH F. Secrete Renin – enzyme to help maintain blood

pressure G. Stimulates red blood cell production

Structure of Kidney

Renal cortex – outer layer, filtration

Renal medulla – middle layer, filtration, absorption

Renal pelvis – urine collection and transport

Renal artery - Renal vein -

Urine Analysis Lab: Crystals

Lab: RBC’s in urine

Will look red under microscope

WBC’s in urine

Blue pigment

Production of Urine –

Nephron – filtering unit (about 1 million) p. 408.

Rate of filtration: 125 ml/min or 45 gallons each day.

Blood in your whole body gets filtered 20 – 25x per day.

                                                                              

                                                                 

1. Filtration – filters blood

   Caused by pressure difference between glomerulus and bowman’s capsule.

  Glomerular filtrate – 180L/day, water, sodium, potassium, chloride, sugar, uric acid, creatine.

   No red blood cells or large proteins found

  Passive transport

Tubular Reabsorbtion

- Valuable molecules reabsorb in blood

 178.5 L reabsorbed (glomerular filtrate back into blood)

  active and passive transport o  glucose, water (passive),

sodium (active) o     hormones help

reabsorbtion – ADH and aldosterone

o     diuretics affect this process

Tubular Reabsorbtion (continued)

Loop of Henle Counter- current

exchange Used to create a

concentration gradient to absorb water

Active transport of Na+ and facilitated diffusion of C-

Tubular Secretion

Small amount of substances (uric acid, ammonium, H ions) move from blood back to nephron

(tubular secretion)Hormonal Control    Antidiuretic Hormone – (ADH)1.      Produced by hypothalamus2.      Stimulates reabsorbtion of water3.      Hydrated – decrease in production of ADH; increase in

urine.4.      Dehydrated – increase ADH production5.      Diurectics – inhibit the absorption of water i.e.

caffeine, alcohol

(secretion)Aldosterone

A.      adrenal hormone, maintains sodium and potassium balance. Increase blood volume

Diabetes mellitus (endocrine)

Chronic disease of insulin deficiency or resistance

Insulin – allows sugar to be used as fuel Type 1 – pancreatic cells destroyed

(autoimmune) Type 2 – resistance to insulin

Kidney Stones

Renin-Angiotensin System

Regulates the body’s sodium and water levels for blood pressure.

Steps of System: Glomerular cells secrete renin into blood 2. Angiotensinogen (inactive in blood plasma), 3. In the liver coverts Angiotensinogen to hormone

Angiotensin II 4. Constricts blood vessels 5. Also, causes Aldosterone to be secreated to help retain

water and decrease renin production.