Urinary SystemUrinary System

Human Physiology – NTN 1224

Faculty of Livestock Fisheries & NutritionWayamba University of Srilanka

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TopicsTopicsAnatomy of Kidney

Functions of Kidney

Functional Unit Of Kidney – Nephron

Anatomy of Urinary Bladder

Anatomy of Urethra

Hormone controls

Summary

Kidney LocationKidney Location

Lateral to vertebral column high on body wall, under floating ribs in retro-peritoneal position

Sectional AnatomySectional Anatomy

Cortex: outer layer, light reddish brow, granular appearance (due to many capillaries)

Medulla: darker striped appearance (due to tubules) Subdivided into distinct renal pyramids, terminating with a papilla. Separated by renal columns from the cortex.

Urine collection: Urine collection:

Ducts within each renalpapilla release urine into minor calyx

major calyx

renal pelvis

ureter

Functions of Urinary System (Kidneys):Functions of Urinary System (Kidneys):Regulate various properties of the

blood.

Ionic composition

PH

Volume

pressure Produce hormones

Excrete waste products & foreign substances.

Functional unit: NephronFunctional unit: Nephron

Renal corpuscle:– Glomerulus– Bowman’s capsule

• Tubular passageways with associated blood vessels:– Proximal Convoluted Tubule– Loop Of Henle– Distal Convoluted Tubule– Collecting Duct

Two Types of NephronsTwo Types of Nephrons

• Cortical nephrons (85%) shorter, mostly in cortex of kidney,

• Juxtamedullary nephrons (15%), "juxta-next-to" the medulla - responsive to ADH, can concentrate urine

Anatomy of Urinary BladderAnatomy of Urinary Bladder Hollow muscular organ

Internal folds - rugae - permit expansion (max. holding capacity ~ 1L)

Area at base delineated by openings of ureters and urethra - without muscle

Consist of…1. Transitional epithelium2. Detrusor muscle – smooth muscle

Transitional EpitheliumTransitional Epithelium

empty bladderfull bladder

from renal pelvis toneck of urethra.

UrethraUrethra Muscular tube

2 types 1)External urethral sphincters – voluntary skeletal

muscle spincter2)Internal urethral sphincter-involuntery smooth

muscle spincter

Female - short – from base of bladder to vestibuleMale

1. prostatic urethra2. membranous urethra3. penile (spongy) urethra

Hormonal Control of Kidney FunctionHormonal Control of Kidney Function

Hormonal Control of Hormonal Control of Kidney FunctionKidney Function

hypothalamushypothalamus

posterior pituitaryposterior pituitary

antidiuretic hormoneantidiuretic hormone

collecting ductscollecting ducts

Hormonal Control of

Kidney Function

Hormonal Control of Hormonal Control of Kidney FunctionKidney Function

reduced blood pressure and reduced blood pressure and glomerular filtrateglomerular filtrate

juxtaglomerular apparatusjuxtaglomerular apparatus

reninrenin

Hormonal Control of Kidney Hormonal Control of Kidney FunctionFunction

reninreninangiotensinogenangiotensinogen

angiotensin Iangiotensin I

angiotensin IIangiotensin II

Hormonal Control of Kidney Hormonal Control of Kidney FunctionFunction

adrenal cortexadrenal cortex

aldosteronealdosterone

angiotensin IIangiotensin II

convoluted tubulesconvoluted tubules

 Glucose- when present in urine condition called glycosuria (nonpathological) [glucose not normally found in urine]

Indicative of:• Excessive carbohydrate intake• Stress• Diabetes mellitus

Abnormal Constitutes of UrineAbnormal Constitutes of Urine

Albumin-abnormal in urine; it’s a very large molecule, too large to pass through glomerular membrane > abnormal increase in permeability of membrane

Albuminuria- nonpathological conditions- excessive exertion, pregnancy, overabundant protein intake-- leads to physiologic albuminuria

Pathological condition- kidney trauma due to blows, heavy metals, bacterial toxin

Abnormal Constitutes of UrineAbnormal Constitutes of Urine

Ketone bodies- normal in urine but in small amts

Ketonuria- find during starvation, using fat stores

Ketonuria is couples w/a finding of glycosuria-- which is usually diagnosed as diabetes mellitus

RBC-hematuria

Hemoglobin-

Hemoglobinuria- due to fragmentation or hemolysis of RBC; conditions: hemolytic anemia, transfusion reaction, burns or renal disease

Abnormal Constitutes of UrineAbnormal Constitutes of Urine

Bile pigments-

Bilirubinuria (bile pigment in urine)- liver pathology such as hepatitis or cirrhosis

WBC-

Pyuria- urinary tract infection; indicates inflammation of urinary tract

Casts- hardened cell fragments, cylindrical, flushed out of urinary tract

WBC casts- pyelonephritus

RBC casts- glomerulonephritus

Fatty casts- renal damage

Abnormal Constitutes of UrineAbnormal Constitutes of Urine

SummarySummary There are several important functions.

1) Excretion of waste products of metabolism.

2) Maintenance of a constant extracellular

environment

3) Production of the hormones erythropoietin and

renin,

4) Metabolism of vitamin D to its active form.

Nephron is the functional unit of kidney,

Involves in formation of urine.

1. List several functions of the kidneys.2. What is the glomerulus? 3. What does the glomerulus do?4. What are several constitutes you should not find in

urine?5. What are the two hormones effect fluid volume and

sodium concentration in the urine?6. Where are the pyramids located in the kidney?7. What vessel directs blood into the glomerulus?8. Where does most selective reabsorption occur in the

nephron?9. What are the hormones important in action of kidney? 10.How the anatomy of urinary bladder helps to its

function?

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