Urinary Anatomy PDF

Urinary System Urinary system The urinary system Function: Remove waste products and drugs from the body. Balance the body's fluids. Release hormones to regulate blood pressure. Maintain salt balance. Maintain blood pH. Dr. Ali Mohammed Urinary system Parts of the urinary system : The urinary system...

Urinary System Urinary system The urinary system Function: Remove waste products and drugs from the body. Balance the body's fluids. Release hormones to regulate blood pressure. Maintain salt balance. Maintain blood pH. Dr. Ali Mohammed Urinary system Parts of the urinary system : The urinary system consists from : The kidneys. Ureters. Urinary bladder. Urethra. Dr. Ali Mohammed Urinary system the urinary system Dr. Ali Mohammed Urinary system parts of the urinary system Dr. Ali Mohammed Urinary system male and female urinary system Dr. Ali Mohammed Urinary system The kidneys : The kidneys are bilateral bean-shaped organs, they are reddish-brown in color. They are situated posteriorly behind the peritoneum, on each side of the vertebral column, and are surrounded by adipose tissue. The right kidney is usually slightly inferior to the left, reflecting its relationship to the liver. The left is a little longer and narrower than the right. Dr. Ali Mohammed Urinary system In adults, the normal kidney measures about 12×6×3 cm; the left kidney may be (1.5) cm longer than the right, and weigh about 130-150 gm ( the average weight is 150 g in men and 135 g in women). The adrenal glands sit immediately superior to the kidneys within a separate envelope of the renal fascia. Dr. Ali Mohammed Urinary system location of the kidney Dr. Ali Mohammed Structure of the kidney Urinary system Structure of the kidney : The kidneys are encased in complex layers of fascia and fat. They are arranged as follows (deep to superficial): Renal capsule - tough fibrous capsule. Peri-renal fat - collection of extra-peritoneal fat. Renal fascia (also known as Gerota’s fascia or perirenal fascia) is a dense, elastic connective tissue sheath that envelops each kidney and suprarenal gland. Pararenal fat - mainly located on the posterolateral aspect of the kidney Dr. Ali Mohammed Urinary system fascia of the kidney Dr. Ali Mohammed Urinary system The renal parenchyma can be divided into two main areas - the outer cortex and inner medulla. The cortex extends into the medulla. The main unit of the medulla is the renal pyramid. There are 8-18 renal pyramids in each kidney, they look like triangles lined next to each other with their bases directed toward the cortex and apex to the hilum. The hilum: it is a depression at the medial border transmitting the renal vessels and nerves and the renal pelvis (the beginning of the ureter). Dr. Ali Mohammed Urinary system This apical projection is called the renal papilla and it opens to the minor calyx. The minor calyces unite to form a major calyx. Usually, there are two to three major calyces in the kidney (superior, middle, and inferior), which again unite to form the renal pelvis from which the ureter emerges and leaves the kidney through the hilum. The pyramids are separated by extensions of the cortex called the renal columns. The pyramids contain the functional units of the kidney, the nephrons Dr. Ali Mohammed Urinary system the kidney Dr. Ali Mohammed Urinary system Blood supply to the kidney : Arteries : Each kidney is supplied by a single renal artery, which is a direct lateral branch of the abdominal aorta, with the right renal artery is longer. In addition to the renal artery, accessory renal arteries are present too. They are branches of the abdominal aorta and all together are called the extra hilar renal arteries. When the renal arteries enter the kidney through the hilum, they split into anterior and posterior branches. Dr. Ali Mohammed Urinary system The posterior branch supplies the posterior part of the kidney, whereas the anterior branch arborizes into five segmental arteries, each supplying a different renal segment. The segmental arteries then branch into the interlobar arteries, which further branch into the arcuate arteries. Finally, the arcuate arteries branch into the interlobular arteries which branch off even further by giving afferent arterioles to run blood past the glomerulus for blood filtration. Dr. Ali Mohammed Urinary system the Renal portal system Dr. Ali Mohammed Urinary system the portal system Dr. Ali Mohammed Urinary system Each kidney has a single renal vein which conducts the blood out of the kidney they leave the renal hilum anteriorly to the renal arteries, and empty directly into the inferior vena cava. As the vena cava lies slightly to the right, the left renal vein is longer. About lymphatic drainage, each kidney drains into the lateral aortic (lumbar) lymph nodes, which are placed around the origin of the renal artery. Dr. Ali Mohammed Urinary system vessels of the kidney Dr. Ali Mohammed Urinary system Innervation : The kidneys are innervated by the renal plexus. This plexus provides input from: The sympathetic nervous system from the lower thoracic splanchnic nerves for the regulation of the vascular tone. The parasympathetic nervous system as well, through the vagus nerve. Dr. Ali Mohammed The ureters Urinary system The ureters : The ureters are two thick muscular tubes which act to transport urine from the kidney to the bladder. They are approximately 25 cm long and are situated bilaterally, with each ureter draining one kidney. The anatomical course of the ureters can be divided into abdominal and pelvic components, because it arise in the abdomen as a continuation of the renal pelvis, and terminate in the pelvic cavity -where they empty into the bladder. Dr. Ali Mohammed Urinary system the urinary system Dr. Ali Mohammed Urinary system the urinary system Dr. Ali Mohammed Urinary system The point at which the renal pelvis narrows to form the ureter is known as the ureteropelvic junction. The arterial supply to the ureters can be divided into abdominal and pelvic supply: Abdominal part: renal artery, testicular/ovarian artery, and ureteral branches directly from the abdominal aorta Pelvic part superior and inferior vesical arteries. Dr. Ali Mohammed Urinary system blood supply to the ureter Dr. Ali Mohammed Urinary system Venous drainage is carried out by vessels that correspond to the aforementioned arteries. Nervous supply to the ureters is delivered via the renal, testicular/ovarian and hypogastric plexuses. The lymphatic drainage : The left ureter is primarily to the left para-aortic lymph nodes The right ureter primarily drains to the right para-caval and inter-aortocaval lymph nodes. Dr. Ali Mohammed Urinary system lymphatic drainage from kidney and ureter Dr. Ali Mohammed The urinary bladder Urinary system The urinary bladder : The bladder is a hollow organ with distensible walls. It is located in the pelvic cavity, posterior to the pubis symphysis. It has a folded internal lining (known as rugae). The urinary bladder plays two main roles: Temporary storage of urine: the folded internal lining, allows it to accommodate up to 400-600ml of urine in healthy adults. Assists in the expulsion of urine: the musculature of the bladder contracts during micturition, with concomitant relaxation of the sphincters. Dr. Ali Mohammed Urinary system Shape of the Bladder : The appearance of the bladder varies depending on the amount of urine stored. When full, it exhibits an oval shape, and when empty it is flattened by the overlying bowel. The external features of the bladder are: Apex - located superiorly, pointing towards the pubic symphysis. Body - main part of the bladder, located between the apex and the fundus Fundus (or base) - located posteriorly. It is triangular-shaped, with the tip of the triangle pointing backwards. Neck - formed by the convergence of the fundus and the two inferolateral surfaces. It is continuous with the urethra. Dr. Ali Mohammed Urinary system urinary bladder Dr. Ali Mohammed Urinary system Musculature : The musculature of the bladder plays a key role in the storage and emptying of urine. Micturition : The bladder wall contains specialized smooth muscle known as detrusor muscle. It receives innervation from both the sympathetic and parasympathetic nervous systems. Internal and external urethral sphincters Dr. Ali Mohammed Urinary system The internal sphincter is involuntary The external sphincter is voluntary The vasculature of the bladder is primarily derived from the internal iliac vessels. Arterial supply is via the superior vesical branch of the internal iliac artery. Venous drainage is achieved by the vesical venous plexus, which empties into the internal iliac veins. Dr. Ali Mohammed Urinary system urinary bladder and urethra Dr. Ali Mohammed Urinary system blood supply to the urinary bladder Dr. Ali Mohammed Urinary system Lymphatics : The superolateral aspect of the bladder drains into the external iliac lymph nodes. The neck and fundus drain into the internal iliac, sacral and common iliac nodes. Nervous supply Neurological control is complex, with the bladder receiving input from both the autonomic (sympathetic and parasympathetic) and somatic arms of the nervous system Dr. Ali Mohammed Urinary system The urethra : The urethra is responsible for transporting urine from the bladder to an external opening in the perineum. It is lined by stratified columnar epithelium, which is protected from the corrosive urine by mucus secreting glands. Male Urethra The male urethra is approximately 15-20cm long. In addition to urine, the male urethra transports semen. Dr. Ali Mohammed Urinary system The male urethra can be divided anatomically into three parts (proximal to distal): Prostatic urethra: Begins as a continuation of the bladder neck and passes through the prostate gland. Membranous urethra: Passes through the pelvic floor and the deep perineal pouch. Penile (bulbous) urethra: Passes through the bulb and corpus spongiosum of the penis,ending at the urethral orifice (the meatus). Dr. Ali Mohammed Urinary system Female Urethra : In females, the urethra is relatively short (approximately 4cm). Dr. Ali Mohammed Urinary system male urethra Dr. Ali Mohammed