The Excretory The Excretory SystemSystemGetting rid of metabolic wastes!Getting rid of metabolic wastes!

Excretory System: The Excretory System: The FunctionFunction

To rid the body of wastes due to To rid the body of wastes due to metabolic activitymetabolic activity

This is essential to maintain This is essential to maintain homeostasishomeostasis

Excretory System: The Excretory System: The OrgansOrgans

SKINSKIN:: Rids body of excess water and salt (SWEAT)Rids body of excess water and salt (SWEAT)

LUNGSLUNGS:: Rids body of CORids body of CO22

KIDNEYS:KIDNEYS: Filter bloodFilter blood Maintain blood pHMaintain blood pH Maintain blood volumeMaintain blood volume

Excretory System: The KidneysExcretory System: The Kidneys RENALRENAL::

Refers to anything doing with Refers to anything doing with the kidneysthe kidneys

Kidneys involved w/ these Kidneys involved w/ these structures:structures: UreterUreter::

Tubes that carry urine to bladder Tubes that carry urine to bladder from kidneysfrom kidneys

Urinary bladder:Urinary bladder: Collects urine for excretionCollects urine for excretion

UrethraUrethra:: Transports urine out of body Transports urine out of body

from bladderfrom bladder

Kidney StructureKidney Structure Renal Artery:Renal Artery:

Carries unfiltered (dirty) blood from Carries unfiltered (dirty) blood from heart TO kidneysheart TO kidneys

Renal Vein:Renal Vein: Carries filtered (clean) blood from Carries filtered (clean) blood from

kidneys TO heartkidneys TO heart

Renal CortexRenal Cortex:: Outer portionOuter portion

Renal MedullaRenal Medulla:: ““Corn” shaped inner portionCorn” shaped inner portion

NephronsNephrons:: Functional unit of the kidneys!Functional unit of the kidneys! Lie between cortex and medullaLie between cortex and medulla Millions of them!Millions of them!

Excretory System: Excretory System: The NephronThe Nephron

Excretory System: The NephronExcretory System: The Nephron Nephrons are the functional Nephrons are the functional

units of the kidneyunits of the kidney This is where filtration, pH This is where filtration, pH

balance, and blood volume are balance, and blood volume are maintained!maintained!

GlomerulusGlomerulus:: Bundle of capillariesBundle of capillaries

Bowman’s Capsule:Bowman’s Capsule: Surround glomerulusSurround glomerulus

Loop of Henle:Loop of Henle: Maintains water balanceMaintains water balance

Collecting Duct:Collecting Duct: Collects wastes from filtered bloodCollects wastes from filtered blood Connected to Connected to ureterureter

Excretory System: Nephron Excretory System: Nephron ProcessProcess

Nephrons clean and maintain blood in Nephrons clean and maintain blood in 3 steps3 steps::1.1. Filtration (filtering of blood):Filtration (filtering of blood):Glomerulus Glomerulus PRESSURE PRESSURE Bowman’s Capsule Bowman’s Capsule

Blood is filtered of water, urea, salts, and other materialsBlood is filtered of water, urea, salts, and other materials These filtered materials called These filtered materials called FILTRATEFILTRATE

2.2. Reabsorption (maintaining blood volume and Reabsorption (maintaining blood volume and nutrients)nutrients) The “good” part of filtrate is reabsorbed by bloodThe “good” part of filtrate is reabsorbed by blood

Most filtered water re-enters blood to maintain volumeMost filtered water re-enters blood to maintain volume

3.3. Secretion: (maintaining blood pH)Secretion: (maintaining blood pH) The “bad” part of filtrate is secreted back into filtrateThe “bad” part of filtrate is secreted back into filtrate

H+ ions, some water, salts, and ureaH+ ions, some water, salts, and urea These together are called These together are called URINEURINE!!

UrinationUrination::Urine in Loop of Henle Urine in Loop of Henle Collecting Duct Collecting Duct Ureter Ureter Bladder Bladder Urethra Urethra