BMS 231: 2015/2016

Anatomy of the Urinary System

DR SOBIA IKRAMDR AQEELA BANODR SADIA FARHAN

Table of Contents

1. Objectives for this lesson2. Functions and Organisation of the Urinary

system3. Location and External anatomy of the

kidney.4. Internal Gross anatomy and parts of the

kidney5. Parts of the nephron and general

functioning of the nephron..6. Definition ,function and location of the

Urinary Bladder, ureters and urethra.

Objectives

When you finish this lesson, you should be able to

• Describe the Functions and Organisation of the Urinary system .

• Understand the Location and External Anatomy of the kidney.

• Identify the Internal gross Anatomy and parts of the kidney.

• Understand the parts of the nephron and their general functioning.

• Define and explain the location and functions of the urinary bladder, ureters and urethra.

Functions of the urinary system

1. Remove nitrogenous wastes (urine)2. Maintain electrolyte, acid-base, and

fluid balance of blood3. Homeostatic organ4. Acts as blood filter5. Release hormones: calcitriol &

erythropoietin

Organs of the Urinary System

5

• Kidneys

• Ureters

• Urinary bladder

• Urethra

kidneys• The Kidneys are the blood

filtering organs of the urinary system.

• The kidneys are fist-sized, bean shaped structures that remove nitrogenous wastes (urine).

• The kidneys regulate the amount of water, salts and other substances in the blood.

Location and External Anatomy•Located Retroperitonealy.

•Lateral to T 12 – L 3 Vertebra

L3

HILUM

•Is a depression present On the medial surface of each kidney.•Vessels and nerves enter and exit from the hilum.

RENAL CAPSULE is the membrane that surrounds the kidney.

AN AVERAGE KIDNEY is about 12 cm tall, 6 cm wide, 3

cm thick

Location and External Anatomy

External anatomy of the Kidney

9

12 cm

6cm

3cm

10

Internal Gross Anatomy of the KidneySagittal Section through the Kidney shows

1.Renal cortex

2.Renal Medulla Renal pyramid

3.Renal pelvis Major calices Minor calices

renal capsule

renal cortex

renal medulla

renal pelvis

renal pyramids

ureter

Internal Gross Anatomy of the Kidney

Nephrons

• They are the functioning unit of the kidney

• About 1 million nephrons are in a kidney.

1. Bowman’s capsule2. Glomerulus3. Proximal convoluted tubule4. Loop of Henle5. Distal convoluted tubule6. Collecting tubule

Parts of nephron

Parts of nephron

The ureters are tubes made of smooth muscles that carry urine from the kidneys to the urinary bladder.

Ureter

• Superiorly• Continuous with the

renal pelvis

• Inferiorly• Pass through the

abdominal cavity, behind the peritoneum, into the pelvic cavity where they enter the posterior wall of the bladder

• 25-30 cm in length17

Ureter

Urinary bladder

Sagittal section of male and female bladder

Urinary Bladder

Wall of bladder

– Mucosa ( inner)

– Muscular layer (middle )• Detrusor

– Adventitia (outer)

Internal urethral sphincter:

• Smooth muscle• Involuntary control• More superiorly located

External Urethral sphincter:

• Skeletal muscle• Voluntary control• Posteriorly located

Sphincters of the Bladder

http://www.google.com.au/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCOT8vJnk18cCFYvtFAodOVgI2w&url=http://www.slideshare.net/gamalsoliman59/physiology-and-anatomy-of-urinary-system&bvm=bv.101800829,d.ZGU&psig=AFQjCNEF0x2H9d85FDds3qtLGopegRk7Qg&ust=1441263740031327

• IN FEMALES– Length of 3–4 cm

• IN MALES – 20 cm in length – three regions anatomically

– Prostatic urethra• Passes through the prostate gland

– Membranous urethra• Through the urogenital diaphragm

– Spongy (penile) urethra• Passes through the length of the penis

Urethra

Sagittal section of Urethra

Frontal view of male urethra

26

Frontal view of female urethra

Frontal view of female urethra