University:
Kentucky State University
Course:
BIO 301 | Human Anatomy
Academic year:

2019
Views:

291

Pages:

70
Author:

plenceplubparun2

Urinary System The urinary system is composed of two kidneys ,two ureters ,urinary bladder and urethra The main function is  Excrete most of the waste products of metabolism.  Control the water and electrolyte balance within the body .  Maintain the acid–base balance of the blood. Location: Kidneys  The kidneys are retroperitoneal organs, on the posterior abdominal wall .  They are located at paravertebral gutters opposite T12, L1, L2, L3 vertebrae.  The right kidney is about 1.25 cm lower than the left.  The upper pole of the right kidney reaches the 12th rib and that of left kidney reaches 11th rib.  The hilum of right kidney is just below transpyloric plane (L1), and that of the left kidney is just above it.  Kidneys Can be palpated in thin people ,By press between 11th and 12th ribs and iliac crest (posteriorly ) and below costal margin (anteriorly) General Features of the Kidneys: The kidneys has : Two poles (upper and lower) The upper pole is nearer to the midline than the lower pole. The inferior pole of right kidney is about one finger breadth above iliac crest  Two borders (lateral and medial). The lateral border is smooth and convex the medial is concave and presents a hilum at its middle. The hilum leads to a space within the kidney, called the sinus of the kidney. The structures passes through the hilum are renal vein, renal artery, renal pelvis. The renal vein is most anterior and renal pelvis is most posterior.  Two surfaces (anterior and posterior). Coverings of the kidney :From the cortex outwards 1- Fibrous capsule; surrounds the kidney all around 2- The perirenal fat; surrounds the kidney all around 3- Renal fascia; it is formed of 2 layers which cover the front and back of the kidneys. The renal fascia is continuous Laterally with fascia transversalis, Medially with the fascia around the renal vessels, aorta and IVC. Superiorly with the diaphragmatic fascia after forming a separate compartment for the suprarenal gland. Inferiorly it remains separate in front and back of the ureter. 4- Pararenal fat outside the renal fascia, most condensed posterior to the kidney Supporting factors of the kidney :The kidney is kept in situ by  Adjacent organs  Abdominal pressure  Perirenal fat  Renal Fascia  Pararenal fat  Renal Blood vessels and ureters If the fat absorbed, as in rapid weight loss, descent of the kidney occurs (Nephroptosis). Nephroptosis cause intermittent pain in the renal region, relieved by lying down. This pain as result of traction on the renal vessels. Kidneys Transplantation The site of renal transplantation is the iliac fossa of the greater pelvis ,due to lack of inferior support for the kidneys in the lumbar region Perinephric Abscess (pus around the kidney)  The attachments of the renal fascia to the renal vessels and ureter, usually preventing the spread of pus to the contralateral side.  Pus from an abscess (or blood from an injured kidney) may spread into the pelvis between the loosely attached anterior and posterior layers of the renal fascia. Relation of the Kidneys Posterior relations; are nearly similar for both kidneys 1- Four muscles, diaphragm (superiorly), psoas major, quadratus lumborum and transversus abdominis. 2-Four neurovascular structures; subcostal vessels, and subcostal, ilioohypogastric, and ilioinguinal nerves. 3-Pleura and ribs, the diaphragm separates the upper part of each kidney from the costodiaphragmatic recess of the pleura and 12th rib on right side and 11th and 12th ribs on left side. Anterior relations Right Kidney Left Kidney Right suprarenal gland Left suprarenal gland Second part of duodenum Spleen with lienorenal ligament, Body of pancreas with splenic vessels Right lobe of liver (with hepatorenal pouch in between) Posterior surface of stomach (with lesser sac in between) Right colic flexure Descending colon Coils of small intestine Coils of small intestine Ascending branch of right colic artery ascending branch of left colic artery Peritoneal covering of the kidney :Although, the kidneys are retroperitoneal, the anterior surface of each kidney has 3 bare areas not covered by peritoneum. The other retroperitoneal structures are interposed between front of kidneys and the parietal peritoneum of posterior abdominal wall. Bare areas on right kidney Bare areas on left kidney Suprarenal area Suprarenal area Duodenal area Pancreatic area Colic area (hepatic flexure) Colic area (descending colon) Structure of the kidney :The Kidneys has two zones (outer cortex and inner medulla) surrounding sinus of the kidney. 1- Cortex; pale and adjacent to the capsule. It is divided into; Cortical arches which form caps over the bases of the medullary pyramids. 2- Medulla; is darker, deep to the cortex.  It is formed of 7-14 pyramids  Each pyramid has a base directed towards the cortex and an apex called renal papilla  The part of cortex between the medullary pyramids is called Renal columns  Each pyramid with its cap of cortex form a lobe of the kidney (7-14 lobes) • The minor calyces are about 5-12 per kidney. Each is a short funnel like tube which receives renal papillae • The minor calyces unite to form 2-3 major calyces (in each kidney) and these in turn, unite to form the renal pelvis. Arterial blood supply  The renal arteries arise from the side of abdominal aorta, opposite the upper border of L2 vertebra.  The right renal artery is longer than the left and passes posterior to IVC  The renal artery gives inferior suprarenal artery,  It divides into 5 segmental arteries which are end arteries. Renal Artery 5 Segmental arteries Lobar arteries one for each renal pyramid Interlobar arteries run toward the cortex on each side of the renal pyramid arcuate arteries arch over the bases of the pyramids interlobular arteries ascend in the cortex glomerular arterioles Venous drainage * Both right and left renal veins open directly into IVC • Left renal vein is longer than the right and passes anterior to the aorta below origin of the superior mesenteric artery. • The-left vein receives the left suprarenal and left gonadal veins vein. Lymph drainage To lateral aortic lymph nodes. Nerve supply :By renal plexus derived from the coeliac plexus and supplemented by the lowest splanchnic nerve. It is mainly vasomotor in function. Renal Vein Entrapment Syndrome (Nutcracker syndrome) Compression of left renal vein between the SMA anteriorly and the abdominal aorta posteriorly . Clinical presentation Haematuria due to renal venous hypertension, rupture of thin-walled veins into the collecting system Renal Pain Renal pain varies from a dull ache to a severe pain in the flank Renal pain can result from stretching of the kidney capsule or spasm of the smooth muscle in the renal pelvis. Afferent nerve renal plexus around the renal artery lowest splanchnic nerve spinal cord at the level of T12 Pain is referred the flank and the anterior abdominal wall along distribution of the subcostal nerve (T12) Surface anatomy of the Kidneys Morris rectangle : Two vertical lines are drawn; one and three inches from the middle line. Two horizontal planes are drawn opposite the spines of T11 and L3 . • The upper end lies 1 inch from midline opposite upper end of T12 vertebra. • The hilum is 2 inches from midline at the transpyloric plane (L1) • The lower end is 3 inches from the midline opposite L3 vertebra Kidney Trauma  The kidneys are well protected by the lower ribs, the lumbar muscles, and the vertebral column.  A severe blunt trauma to the abdomen may crush the kidney against the last rib and the vertebral column.  Depending on the severity of the blow, the injury varies from a mild bruising to a complete laceration  Because 25% of the cardiac outflow passes through the kidneys, renal injury can result in rapid blood loss The ureters: The ureters are muscular tubes which convey urine from kidneys to the urinary bladder. The ureter lies behind and adheres to the parietal peritoneum of the posterior abdominal wall. The ureter is about 10 inches (25 cm) and has 2 parts; abdominal and pelvic, each is 5 inches long. Course of the ureter The abdominal part  Begins from the lower end of the renal pelvis (it is the pelvi-ureteric junction),  It descends downwards and medially on psoas major muscle towards the pelvic brim.  It crosses the end of the common or beginning of the external iliac artery to become the pelvic part. The pelvic part  Descends downwards and backwards along the anterior margin of greater sciatic foramen till the ischial spine. It forms posterior boundary of the ovarian fossa.  It runs forwards on pelvic floor to open in the wall of the urinary bladder.  It is crossed by the vas deferens in male and uterine artery in females.  It pierces the wall of the bladder obliquely to open at the superolateral angle of the trigone.  This oblique termination of the ureter prevents regurgitation of urine from bladder to the ureter Relations of the abdominal part of ureter:Posterior Relation (BOTH SIDES) 1.Psoas major muscle separating the ureter from the tips of the transverse processes of the lumbar vertebrae (2-5) 2.Genitofernoral nerve 3.Termination of common or beginning of external iliac artery Anterior and medial relations Right ureter 1. Third part of the duodenum at its beginning 2. Terminal ileum near the pelvic brim Left ureter 1. Sigmoid colon near the pelvic brim Peritoneal elements 1. Parietal peritoneum of the posterior abdominal wall 2. Root of the mesentery 1. Parietal peritoneum of the posterior abdominal wall 2. Apex of sigmoid mesocolon with its intersigmoid recess vessels 1. 2. 3. 4.  1. Left gonadal vessels 2. Left colic vessels 3. Sigmoid vessels Anterior relation Intestinal structures Medial relation Right gonadal vessels Superior mesenteric vessels Right colic vessels Ilio-colic vessels Inferior vena cava  Inferior mesenteric vein Constrictions of the ureters Site of constriction Corresponding bony Level At pelvi-ureteric junction Near the tip of the transverse process of L2 vertebra At pelvic brim In front of sacroiliac joint. In the wall of the urinary bladder Just medial to the ischial spine. (it is the narrowest point whole ureter) of the Arterial blood supply : Abdominal part receives branches from renal artery, abdominal aorta, gonadal and common iliac arteries  Pelvic part receives branches from vesical, middle rectal and uterine arteries Lymph drainage:To lateral aortic, common iliac lymph nodes. Nerve supply : The ureter receives sympathetic fibers from T11 – L2 segments of spinal cord.  Sensory fibers from the ureter enter the spinal cord through the same segments.  Ureteric colic begins in the loin and is referred to groin, Anterior aspect of the thigh through genitofemoral nerve (L1,L2) and scrotum or labium majora Surface markings :- The ureter begins at a point on the transpyloric plane, 5 cm from the midline It enters the bladder at the pubic tubercle. Intra Venous Urogram IVU IVU KUB MRI Abdomen MRI Abdomen Urinary Bladder The urinary bladder is a hollow viscus with strong muscular walls which acts as a reservoir for urine. Site of Urinary Bladder In infants: the bladder lies in the abdomen At about 6 years of age : the bladder begins to enter the enlarging pelvis. After puberty : the bladder lies within the lesser pelvis . In the adult: an empty bladder lies in lesser pelvis and as it fills, it ascends to the greater pelvis. Capacity of the Bladder: • Average capacity of adult bladder is about 300 ml. • Distension of the bladder by 500 ml may be tolerated. Beyond this, distension of the bladder is painful The bladder is enveloped in loose connective tissue called vesical fascia in which vesical venous plexus is embedded. Description and Relations of the Urinary Bladder : • The empty bladder has; Apex, base, 3 surfaces (superior, right and left inferolateral) and neck . 1- Apex of the bladder:  Is continuous with the median umbilical ligament which raises the medianumbilical fold of peritoneum.  The ligament is the remnant of the embryonic urachus. 2- Base of the bladder (fundus) :  It is directed posteroinferiorly  Its superolateral angles receive the ureters  Relations : Male  Base is related to rectum, but separated from it by  Rectovesical pouch  2 seminal vesicles  Ampullae of the deferent ducts. female The base is related to upper part of anterior wall of vagina. 3-Superior Surface: is covered by peritoneum and is related to Male  Sigmoid colon,  Loops if ileum female  Vesical surface of uterus.  Supravaginal part of cervix with uterovesical pouch in between 4-Inferolateral surface: It is not covered by peritoneum.It is related to:  Body of pubis with retropubic pad of fat in the retropubic space of Retzius.  Levator ani.  Obturator internus. 5-Neck of the bladder: It is the lowest and most fixed pan of the bladder.  In the male: it is continuous with the urethra at the internal ureteral meatus and rests on the upper surface of the prostate.  In female: it is continuous with the urethra and rests in the pelvic fascia which surrounds the urethra. At the junction of the neck and urethra, sphincter vesicae is present. Muscular coat of the bladder is composed of smooth muscle and is arranged as three layers known as the detrusor muscle. Peritoneal Covering of the Bladder :  In male, the superior surface and the superior part of its base is covered by peritoneum,  In females, only the superior surface is covered by peritoneum. The peritoneum leaving the bladder is loosely attached to the suprapubic part of abdominal wall. The distended bladder lifts this peritoneum from the abdominal wall. In case of suprapubic cystostomy instruments could be introduced into the distended bladder to avoid injury of the peritoneum The ligaments of the bladder: 1-Median umbilical ligament: Continuous with apex of the bladder (it is the embryonic urachus) 2-Puboprostatic and pubovesical ligaments:  In the male, the puboprostatic ligaments extend from back of the bodies of pubic bones to the anterior surface of the sheath of the prostate and neck of the bladder.  In the female, the pubovesical ligaments extend from pubic bones to the urethra and neck of the bladder. 3-Lateral ligaments of the bladder:  Each extends laterally from the side of the base of the bladder across the pelvic floor to the tendinous arch in side wall of the pelvis.  These ligaments enclose arteries and autonomic nerves of the bladder. 4-Posterior ligaments:  Each extends backwards from the base of the bladder to the corresponding internal iliac vein.  They enclose vesical veins in their way to the internal iliac vein. Interior of the Urinary Bladder :  The mucous membrane over most of the bladder is loosely attached to the underlying muscular layer (detrusor muscle).  The mucous membrane is folded in empty bladder, but in distended bladder, the folds disappear. Trigone of the bladder: It is the small triangular area which lies between the orifices of the ureters and the internal urethral meatus. (it is mesodermal in origin). It has the following special features:  Its superior boundary is formed by the interureteric crest (ridge) which connects the two ureteric orifices.  Its mucous membrane is always smooth and firmly adherent to the underlying muscle. It is very sensitive and vascular, so that, in cystoscope it appears red violet in colour  In the male, the trigone overlies the median lobe of the prostate.  After the middle age, the enlarged prostate elevates the mucous membrane behind the internal urethral orifice producing what is known as uvula vesicae of the bladder Arterial Blood Supply: In the male: superior and inferior vesical arteries. In the female: superior vesical and vaginal arteries. Venous Drainage: Begins by the vesical venous plexus, embedded in the visceral fascia on the inferolateral surfaces of the bladder. Inferiorly: In the male: it communicates with the prostatic venous plexus. In the female: it communicates with the vaginal venous plexus and receives the deep dorsal vein of the clitoris. Posteriorly: the plexus is drained by numerous vesical veins which run in the posterior ligaments of the bladder to end in the internal iliac veins. Vesical venous plexus MALE Prostatic venous plexus Posteriorly Internal iliac veins FEMALE Vaginal venous plexus deep dorsal vein of the clitoris Lymphatic Drainage:  To internal and external iliac lymph nodes.  From the bladder neck, lymphatics drain directly to the sacral lymph nodes. Nerve Supply:  By vesical nerve plexus, derived from the inferior hypogastric plexus, it contains t following fibers :  Parasympathetic efferents (pelvic splanchnic nerves) (S2, S3, S4): motor to the detrusor muscle, inhibitory to sphincter vesicae (they produce micturition).  Sympathetic efferents: (L1 ,L2 ) are inhibitory to detrusor and stimulant to sphincter vesicae .  Sensory afferents: Reach central nervous system through pelvic splanchnic nerves or Sympathetic fibers It record bladder distension and pain sensation. Nerve Supply: Bladder Injuries Intraperitoneally Extraperitoneally Usually involves the superior wall of the bladder Usually involves the anterior part of the bladder wall below the level of the peritoneal reflection Most commonly when the bladder is full it most commonly occurs in fractures of the pelvis Urine and blood escape freely into the peritoneal cavity The patient complains of lower abdominal pain and blood in the urine (hematuria) Urethra: Male Urethra  The male urethra is about 20 cm long.  It extends between 2 meatuses. • Internal urethral meatus: at its junction with the neck of the bladder • External urethral meatus:is a vertical slit, about 6 mm long. It is the narrowest part of urethra, and a calculus may lodge there.  It is divided into 4 parts: the first and the second parts are in the pelvis, the third and fourth parts are in the perineum .  It has 2 sphincters: Internal urethral sphincter (or sphincter vesicae), surrounds the neck of urinary bladder and the first (preprostatic) part of the urethra. External urethral sphincter (or sphincter urethrae), surrounds the third (membranous) part of the urethra Parts of the Urethra First part: preprostatic part of urethra Second part: prostatic part of urethra Third part : Fourth : spongy part of membranous part urethra of urethra Length 1-15 cm 3 cm 2 cm 15 cm Site between neck of the bladder and the base of the prostate traverses prostate from base to apex runs in deep perineal pouch bulb of penis and corpus spongiosum(Superficial Perineal Pouch) it is the widest part of urethra it is the least dilatable part Size Special It is surrounded Urethral crest features by internal Seminal colliculus sphincter Prostatic sinuses DR AHMED SALMAN surrounded by external urethral sphincter -Dilated at its beginning to form to form intrabutbar fossa and at termination in glans penis to form the navicular fossa. -The bulbourethral glands open into its beginning Special features of prostatic part of urethra Urethral crest: is a median longitudinal elevation in the mucous membrane of its posterior wall. Seminal colliculus (verumontanum):  Is a prominence at the middle of the crest.  It has three openings ; the opening of the prostatic utricle in its middle, and the openings of the two ejaculatory ducts on the sides. Prostatic sinuses :  Each is a shallow depression on the side of the urethral crest.  Each receives 15-20 prostatic ducts. Sphincters of the Urethra Internal Urethral sphincter External Urethral sphincter Site It lies in pelvis around neck of the It lies in the perineum, surrounds the bladder and preprostatic part of the membranous urethra in the deep urethra. perineal pouch. Structures It is formed of smooth muscle fibers Nerve Supply Autonomic fibers from the inferior hypogastric plexus Functions  It acts Involuntarily.  It is well-developed in both male and female.  It maintains continence of urine. In the male: it has a genital function, it prevents reflux of semen into the urinary bladder during ejaculation It is formed of striated muscle fibers Somatic : from the perineal branch of pudendal nerve of the sacral plexus  It acts voluntarily.  It is well-developed in the male  It maintains continence of urine. Vessels Nerves and Lymphatics of the urethra : Urethra receives its blood and nerve supply from those of prostate and penis. Lymphatics: From the prostatic and membranous parts to internal and external iliac lymph nodes From the spongy part to deep and superficial inguinal lymph nodes. Urinary Retention It is more common in male due to a benign or malignant enlargement of the prostate or acute urethritis or prostatitis . The only anatomic cause of urinary retention in females is acute inflammation around the urethra (e.g., from herpes). Female Urethra : length : 4 cm. Course. Relations:  It begins at the internal urethral meatus at the neck of the bladder.  It traverses the deep perineal pouch to end at the external urethral orifice in the vestibule anterior to the vaginal orifice.  It is embedded in the anterior wall of the vagina.  On each side of the urethra, the mucous membrane of the urethra presents a number of small mucous glands called the paraurethral glands which correspond to the prostate in the male. Clinically Signiﬁcant Differences Between Male and Female Urethrae:  The female urethra is distensible because it contains considerable elastic tissue, as well as smooth muscle.  It can be easily dilated without injury.  Infections of the urethra, and bladder, are more common in women because the female urethra is short, more distensible, and is open to the exterior. Anatomy of the Procedure of Catheterization 1. The patient lies in a supine position. 2. With gentle traction, the penis is held erect at right angles to the anterior abdominal wall. The lubricated catheter is passed through the narrow external urethral meatus. On reaching the membranous part of the urethra, a slight resistance is felt because of the tone of the urethral sphincter and the surrounding rigid perineal membrane. 3. The penis is then lowered toward the thighs, and the catheter is gently pushed through the sphincter 4-Passage of the catheter through the prostatic urethra and bladder neck should be easily.

Urinary System Study Guide

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