Chapter 20Chapter 20

Excretory SystemExcretory System

Excretory System – Structure & Excretory System – Structure & FunctionFunction

A. The body system that A. The body system that collects and removes collects and removes the waste products the waste products (urea, salts, uric acids (urea, salts, uric acids etc.) producedetc.) producedby the cells of the bodyby the cells of the body

B. Organs/structures B. Organs/structures involved include: the involved include: the kidneys, ureter, bladder, kidneys, ureter, bladder, urethraurethra

C. Secondary Organs C. Secondary Organs include Skin, Sweat include Skin, Sweat Glands, Liver and the Glands, Liver and the LungsLungs

Kidney, Ureter, Bladder & Kidney, Ureter, Bladder & Urethra Urethra

KidneyKidney – – Major filtering organ of the Major filtering organ of the

excretory system. Filters blood excretory system. Filters blood to remove toxic cellular wastesto remove toxic cellular wastes

Located Located in the lower back region of the body and is enclosed by connective tissue called a capsule.

Produces urine UreterUreter

Tube (one from each kidney Tube (one from each kidney that drains urine from kidneys that drains urine from kidneys to the bladder to the bladder

BladderBladder Strong muscular organ that

stores the urine until released from the body through the urethra.

UrethraUrethra connects and passes

stored urine out of the body.

Kidney Structure & FunctionKidney Structure & Function CortexCortex:

The outer portion of the kidney that contain the basic functional unit (nephronsnephrons).

Nephrons are small independently filtering units of the kidney.

About million million nephrons in each kidney

MedullaMedulla The inner portion of the kidney

PelvisPelvis The central area of the kidney.

Site where the collecting tubules combine to form the ureter

Adrenal Gland – Endocrine gland secretes adrenaline (not part of the excretory system)

Nephron: StructureNephron: Structure Nephron Nephron – basic – basic

structure of the structure of the kidney. kidney. complex units consisting of arterioles, venules, capillaries

Located in the Renal Cortex

Structures include: arterioles GlomerulusGlomerulus, Bowman’s CapsuleBowman’s Capsule, Loop of HenleLoop of Henle, Collecting TubulesCollecting Tubules, Capillaries and venules

Arteriole

Loop of Henle (the

yellow)

Collecting Tubule

Capillary Network ( the red & blue)

Nephron - FunctionNephron - Function High Blood PressureHigh Blood Pressure in in

the arteriole supplied the arteriole supplied to the Glomerulusto the Glomerulus

GlomerulusGlomerulus “ “leaksleaks” ” both good & bad both good & bad materials into materials into

Bowman’s CapsuleBowman’s Capsule Good – Water, Good – Water,

Amino Acids, Amino Acids, glucoseglucose

Bad – Urea, salts, Bad – Urea, salts, excess water, Uric excess water, Uric AcidAcid

Loop of HenleLoop of Henle Extends down into Extends down into

the renal medullathe renal medulla Materials drain Materials drain

down into loopdown into loop Dense capillary Dense capillary

network surround network surround the loop and the loop and reabsorbs “good” reabsorbs “good” stuff.stuff.

““Bad” stuff Bad” stuff continues down & continues down & around loop around loop

Dumps into the Dumps into the collecting tubulecollecting tubule

Collecting tubules come together & drain the newly formed urine into the ureter.

Capillary network takes reabsorbed materials back to the venules and recirculates back to the body

““Need-to-Knows”Need-to-Knows” AortaAorta Vena CavaVena Cava Adrenal Adrenal

GlandGland BladderBladder UreterUreter UrethraUrethra Renal PelvisRenal Pelvis Renal Renal

MedullaMedulla Renal CortexRenal Cortex ArterioleArteriole Collecting Collecting

TubuleTubule Capillary Capillary

NetworkNetwork Loop of Loop of

HenleHenle Bowman’s Bowman’s

CapsuleCapsule GlomerulusGlomerulus

That’s All Folks!!That’s All Folks!!

Now that wasn’t so bad nowNow that wasn’t so bad now was it? was it?