THE EXCRETORY THE EXCRETORY SYSTEMSYSTEM

Urinary SystemUrinary System

AortaLeft renal artery

Left renal veinVena cava

Left ureterUrinary bladder

Urethra

Right kidney

Adrenal glands (endocrine system)

Structure of the kidneyStructure of the kidney ( to show the position of a nephron)( to show the position of a nephron)

NephronNephron

Process of urine formation.Process of urine formation.

ExcretionExcretion Is the process of removing metabolic waste of Is the process of removing metabolic waste of

products and toxic materials from the bodyproducts and toxic materials from the body Main organ Main organ kidney and skin kidney and skin Excretion and defecation is 2 different processExcretion and defecation is 2 different process

ExcretionExcretion DefecationDefecation

DifferencesDifferences remove metabolic remove metabolic wastewasteWaste and toxic Waste and toxic materials are products materials are products of metabolismof metabolism

Remove undigested Remove undigested food fro the digestive food fro the digestive systemsystemFaeces is not a Faeces is not a product of metabolismproduct of metabolismInvolve large Involve large intestine, rectum and intestine, rectum and anusanus

SimilaritiesSimilarities Remove waste from the bodyRemove waste from the bodyPrevent accumulation of toxic waste in the Prevent accumulation of toxic waste in the bodybody

Urine formationUrine formation Functional unit is the nephronFunctional unit is the nephron Involve 3 processes:Involve 3 processes:

UltrafiltrationUltrafiltration selective reabsorptionselective reabsorption secretionsecretion

UltrafiltrationUltrafiltration Blood flows in the blood capillaries of the Blood flows in the blood capillaries of the

glomerulus to the efferent arterioleglomerulus to the efferent arteriole Blood cells & blood protien are not filtered Blood cells & blood protien are not filtered

and remain in the glomerular capillariesand remain in the glomerular capillaries Afferent arteriole is wider than efferent Afferent arteriole is wider than efferent

arteriole, so the hydrostatic pressure is high.arteriole, so the hydrostatic pressure is high. This pressure cause ultrafiltrationThis pressure cause ultrafiltration

UltrafiltrationUltrafiltration Component are filtrate in to Bowman’s Component are filtrate in to Bowman’s

capsule are:capsule are:1.1. blood plasmablood plasma2.2. UreaUrea3.3. Amino acidsAmino acids4.4. SugarsSugars5.5. SaltsSalts6.6. waterwater

Selective reabsorptionSelective reabsorption Takes place as the filtrate passes along the nephronTakes place as the filtrate passes along the nephron At proximal convulated tubuleAt proximal convulated tubule

65% of water, sugars and amino acids are 65% of water, sugars and amino acids are reabsorb to the capillariesreabsorb to the capillaries

At Henle LoopAt Henle Loop 20% of water and salt is reabsorb20% of water and salt is reabsorb

At distal convulated tubule and collecting ductAt distal convulated tubule and collecting duct water and salt is reabsorb according to the bodywater and salt is reabsorb according to the body needneed

SecretionSecretion Occurs when substances not required by the Occurs when substances not required by the

body are secreted into the filtrate by the cells body are secreted into the filtrate by the cells of the tubule wall.of the tubule wall.

Process of sweatingProcess of sweating Main organ Main organ skin skin Other function done by skin:Other function done by skin: Sweat is a mixture of water, salts and urea.Sweat is a mixture of water, salts and urea.

Process of sweatingProcess of sweating When body temperature is rises,When body temperature is rises,

- the receptors in skin send nerve impulse to - the receptors in skin send nerve impulse to the brainthe brain- blood vessel respond to the brain signal - blood vessel respond to the brain signal and dilateand dilate- this allow more blood flow to the skin- this allow more blood flow to the skin- blood flow carries waste which diffuse into - blood flow carries waste which diffuse into the sweat glandthe sweat gland

Diseases related to the excretory Diseases related to the excretory systemsystem

Kidney failureKidney failure - could result from various - could result from various factor such as bacterial factor such as bacterial infection, injury due to infection, injury due to accident, diabetes or high accident, diabetes or high blood pressure. blood pressure. - Cases major kidney failure - Cases major kidney failure can be managed by can be managed by haemodialysis. In such cases, haemodialysis. In such cases, haemodialysis machine that haemodialysis machine that is used acts as an artificial is used acts as an artificial kidney.kidney.- Another option is kidney - Another option is kidney transplant. transplant.

Formation of gall stonesFormation of gall stones

Dialysis

Preventing of kidney related diseasesPreventing of kidney related diseases

Reducing salts and sugarReducing salts and sugar Drinking plenty of waterDrinking plenty of water Avoiding medications without proper Avoiding medications without proper

prescriptionprescription Stay away from drugs and acoholStay away from drugs and acohol