KIDNEYS The kidney two in number reddish-brown bean-shaped organs Lie against the posterior abdominal wall at the level of T12 to L3 The R kidney is lower than the left because of the space occupied by the __ It weighs about 160 g The lateral surface is convex and the medial surface is concave, a slit called____ that receive renal nerves, blood vessels, lymphatics and ureter
Each kidney is about 12 cm long, 5 cm wide and about 2.5 cm thick. The left is somewhat longer, though narrower than the right . Superior to each kidneys are glands called adrenal gland The kidney adrenal gland, ureter and urinar bladder are located retroperitoneal .weight of the kidney. * adult male ranges from 4.5 – 6 ounces * adult female ranges from 4 – 5.5 ounces
The kidneys are protected by 3 layers of C.T. 1. Fibrous renal fascia- deep to the parietal peritoneum which binds the kidney to associated organs to abdominal wall 2. Adipose capsule- a layer of fats that cushions and hold it in place 3.Renal capsule- a fibrous sac that anchored at the hilum and encloses the rest of the kidney, it protects the kidney from infection and trauma
FUNCTIONS 1. They filter blood plasma, separates waste from useful chemicals and eliminates the waste by returning the rest to the bloodstream 2. They regulate blood volume and regulate osmolarity the body fluid 3. They secretes the enzyme renin which activates hormonal mechanism That control B/P and electrolyte balance
4. They secrete hormone erythropoietin, which controls the RBC count and the O2 capacity of the blood 5. They detoxify free radicals of and drugs with the use peroxisomes
<ul><ul><li>NERVE SUPPLY </li></ul></ul><ul><ul><li>The Nerves of the kidney are derived mainly from the coeliac plexus . </li></ul></ul>
<ul><ul><li>STRUCTURE OF THE KIDNEY </li></ul></ul><ul><ul><ul><li>Renal Cortex: is the relatively thin, outermost layer, about 1 cm thick </li></ul></ul></ul><ul><ul><ul><li>Renal Medulla: is interior to the cortex, which contains the cone-shaped renal pyramids. 6 to 10 in number accdg to saladin; 8 to 18 accdg to gray </li></ul></ul></ul><ul><ul><ul><li>Renal Pelvis: is medial to the medulla. The pelvis, is a flat, funnel-like cavity that is continuous with the ureter. </li></ul></ul></ul>
<ul><li>NEPHRONS </li></ul><ul><li>-Functional units of the kidney. </li></ul><ul><li>-They are microscopic tubules that perform the work of the kidneys. </li></ul><ul><li>They form urine that flows into the collecting ducts of renal pyramids. </li></ul><ul><li>Two principal part are: Renal corpuscle and renal tubule </li></ul>
Two (2) types of nephrons. There are two types of nephrons in the kidney, about 80% are cortical nephrons, and about 20% are juxtamedullary nephrons . 1. Cortical Nephrons 2. Juxtamedullary Nephrons
<ul><ul><ul><ul><ul><li>Cortical Nephrons </li></ul></ul></ul></ul></ul><ul><li>- are located on the outer surface of the kidney cortex. </li></ul><ul><li>- they have short loops of Henle, that penetrate only into the superficial region of the renal cortex. </li></ul>
<ul><li>Juxtamedullary Nephrons </li></ul><ul><li>- located in the cortex near the medulla. </li></ul><ul><li>- t hey have glomeruli deep in the renal cortex, and long loops of Henle that stretch through the renal medulla, almost to the renal papilla. </li></ul>
<ul><li>BLOOD SUPPLY - The Renal Arteries </li></ul><ul><li>arise directly from the aorta and Renal artery supply the kidneys with blood </li></ul><ul><li>Interlobar Arteries , any of the branches of segmental arteries of the kidney that run between the renal lobes and give rise to the arcuate arteries. </li></ul><ul><li>Interlobular arteries , are branches of the arcuate arteries, and run through the cortical labyrinth perpendicular to the kidney capsule, between the medullary rays. </li></ul>
.in the cortex. Afferent arterioles carry blood to a glomerulus Efferent arterioles carries blood away from a glomerulus
<ul><li>PARTS of Nephron </li></ul><ul><li>> Renal Corpuscle: located in the cortex composed of two parts: </li></ul><ul><ul><li>Glomerulus: a clump of arterial capillaries within the Bowman’s capsule </li></ul></ul><ul><ul><li>Bowman’s Capsule: a double walled chamber, located at the closed end. </li></ul></ul>
<ul><li>Renal Tubule: leads away from the glomerular capsule with three sequential segments. </li></ul><ul><ul><ul><ul><li>Proximal Convoluted tubule: the first part of the renal tubule, that is coiled and lined with cells carpeted with microvilli and stuffed with mitochondria </li></ul></ul></ul></ul>
<ul><ul><ul><li>Loop of Henle (nephron loop): the U-shaped second part, that makes a hairpin turn and returns to the peritubular capillaries </li></ul></ul></ul><ul><ul><ul><li>Distal Convoluted tubule: which is highly coiled and surrounded by capillaries. The third segment that unites with a collecting duct. </li></ul></ul></ul>
Collecting tubule- the dct several nephrons drain into straigth tubule, which passes down into the medulla. Near the papilla several collecting ducts merge to form a large PAPILLARY DUCTS.
URINE FORMATION Urine is composed of water, certain electrolytes, and various waste products that are filtered out of the blood system. A major part of this "cleaning" of the blood takes place in the kidneys and, in particular, in the nephrons, where the blood is filtered to produce the urine. Urination is the primary method for excreting toxins, chemicals and drugs from the body .
<ul><li>The nephron makes urine by: </li></ul><ul><li>filtering the blood of its small molecules and ions and then </li></ul><ul><li>reclaiming the needed amounts of useful materials </li></ul><ul><li>surplus or waste molecules and ions are left to flow out as urine </li></ul>
Urine formation thru GI <ul><li>Glomerular filtration- creates a plasmalike filtrate of the blood </li></ul><ul><li>Tubular reabsorption- removes useful solutes from the filtrate, returns them to the blood </li></ul><ul><li>Tubular secretion- removes additional wastes from the blood adds them to filtrate. </li></ul><ul><li>Water conservation- removes water from the urine and returns it into the blood, concentrate wastes. </li></ul>
<ul><li>Glomerular filtration occurs at the bowman’s capsule </li></ul><ul><li>Tubular reabsorption occurs at the proximal convoluted tubule and the peritubular capilliaries </li></ul><ul><li>Tubular secretion occurs at distal convoluted tubule </li></ul><ul><li>Water conservation occurs at the loop of henle and collecting duct. </li></ul>
URETERS A tube that carries urine down from the kidney to the bladder. Each ureter is a muscular tube that extends from the kidney to the posterior surface of the bladder.
Each ureters are small tube about 25 cm long that carries urine from the renal pelvis to the urinary bladder. Smooth muscular tissue in the walls of the ureters peristaltically force the urine downward small amounts of urine are emptied into the urinary bladder from the ureters about every 10 to 15 seconds.
<ul><li>STRUCTURE OF URETER </li></ul><ul><li> 3 COATS: </li></ul><ul><li>The outer fibrous coat - is a supporting layer of fibrous connective tissue. </li></ul><ul><li>(2) The middle layer, or muscular coat - consist of inner circular and outer longitudinal smooth muscle and composed of largely smooth muscle fibers. The main function of this layer is peristalsis to propel the urine. </li></ul>
(3) The inner layer, or mucous coat - is transitional epithelium that is continuous with the linings of the renal tubules and the urinary bladder.
LOCATION Male: the ureter enters the pelvis by crossing the bifurcation of the common iliac artery in front of the sacroiliac joint. Each ureter then runs down the lateral wall of the pelvis in front of the internal iliac artery to the region of the ischial spine and turns forward to enter the lateral angle of the bladder.
Female: the ureter crosses over the pelvic inlet in front of the bifurcation of the common iliac artery. It runs downward and backward in front of the internal iliac artery and behind the ovary until it reaches the region of the ischial spine. It then turns forward and medially beneath the base of the broad ligament, where it is crossed by the uterine artery. The ureter then runs forward, lateral to the lateral fornix of the vagina, to enter the bladder.
BLOOD SUPPLY The arterial supply of the ureters varies according to the individual and also along the length of the ureters. Branches may be received from all of the following: *Renal arteries *Abdominal aorta *Common iliac arteries *Testicular/ovarian arteries *Internal iliac arteries *Vesical/uterine arteries
NERVE SUPPLY Renal, testicular(or ovarian), and hypogastric plexuses(in the pelvis).
URINARY BLADDER The urinary bladder is a hollow, distensible, muscular organ lying in the pelvic cavity. The wall of the bladder is made mostly of a type of smooth muscle called detrusor muscle which has several layers running in different directions. The bladder is enveloped in loose connective tissue called the vesical fascia.
<ul><li>It can hold up to 500ml of urine comfortably for 2 to 5 hours. </li></ul><ul><li>The epithelial tissue associated with the bladder is called transitional epithelium. It allows the bladder to stretch to accommodate urine without rupturing the tissue. It has three openings: 2 ureter openings and </li></ul><ul><ul><ul><li>single opening of the urethra </li></ul></ul></ul>
LOCATION It is located retroperitoneally in the pelvis just posterior to the pubic symphysis. It is held in place by ligaments attached to pelvic bones.
FUNCTION It stores urine as temporarily reservoir for urine It is the organ that collects urine excreted by kidneys prior to disposal by urination. Urine enters the bladder via the ureters and emits via the urethra.
<ul><li>MALE BLADDER </li></ul><ul><li>the bladder is superior to the prostate and separated from the rectum by the rectovesical excavation. </li></ul><ul><li>- the superior surface of the bladder is covered with peritoneum, which separates it from coils of small intestine or from the sigmoid colon. </li></ul>
<ul><li>FEMALE BLADDER </li></ul><ul><li>is in relation behind with the uterus and the upper part of the vagina. </li></ul><ul><li>- stores urine prior to its elimination from the body, the bladder expels urine into the </li></ul><ul><li>urethra, leading to the exterior of the body </li></ul>
<ul><li>REGIONS </li></ul><ul><li>* Trigone - triangular shaped area located on the postero-ingerior wall of the bladder. The urethra emits at the lowest point of the triangle of the trigone. </li></ul><ul><li>*Apex - the medium umbilical ligament connects to the apex of the bladder. </li></ul><ul><li>*Neck - the neck is connected to the public bone by the puber vesical liga ment in women and by the pubo prostatic ligament in men. </li></ul>
LIGAMENTS The bladder is connected to the pelvic wall by the fascia endopelvina * Pubovesicales – muscle fibers that strengthens the front of fascial attachment. * Rectovesicales – wherein other muscular fibers constitute and run from the fundus of the bladder to the sides of the rectum, in the sacrogenital folds. * Middle umbilical ligament - formed when the vertex of the bladder is joined to the umbilicus by the remains of the urachus. Broad at its attachment to the bladder but narrowing as it ascends.
<ul><li>*False ligaments of the bladder – series of folds that carries from the superior surface of the bladder the peritoneum. </li></ul><ul><li>Three folds: </li></ul><ul><ul><li>*middle umbilical fold on the middle umbilical ligament </li></ul></ul><ul><ul><li>*two lateral umbilical folds on the obliterated hypogastric arteries. The reflections of the peritoneum on to the side walls of the pelvis form the lateral false ligaments, while the sacrogenital folds constitute posterior false ligaments. </li></ul></ul>
BLOOD SUPPLY Arterial supply comes mostly from branches of the internal iliac arteries. Female: anteriosuperior parts - superior vesical arteries, posterioinferior parts - vaginal Arteries Male: anteriosuperior parts – superior vesical arteries, posterioinferior parts - inferior vesical arteries
Venous drainage is via venous plexuses. These drain via veins that correspond to the arteries into the internal iliac veins. Female: vesical venous plexus Male: vesical venous plexus, prostatic venous plexus
NERVE SUPPLY The nerves supplying the bladder form the vesical nervous plexus and are both parasympathetic and sympathetic.
<ul><li>The parasympathetic supply is from the pelvic splanchnic nerves (S2,S3,S4) which are: </li></ul><ul><li>motor to the detrusor muscle </li></ul><ul><li>inhibitory to the internal sphincter </li></ul><ul><li>The sympathetic nerve supply to the bladder comes from T11-L1 and is inhibitory to the </li></ul><ul><li>bladder. </li></ul>
URETHRA Muscular tube that drains urine from the bladder and conveys it out of the body. Its wall is lined with mucous membranes and contains a relatively thick layer of smooth muscle tissue. It also contains numerous mucous glands called urethral glands , that secrete mucus into the urethral canal.
<ul><li>MALE URETHRA </li></ul><ul><li>a channel which extends from the internal urethral orifice in the urinary bladder to the external urethral orifice at the end of the penis. </li></ul><ul><li>it presents a double curve in the ordinary relaxed state of the penis. </li></ul><ul><li>- its length varies from 17.5 to 20 cm/ 8 inches long and opens at the end of penis. </li></ul>
FUNCTION * urinary canal and a passageway of cells and secretions from various reproductive organs Or it also affords an exit for the seminal products * secretion of prostatic and bulbo-urethral glands
THREE PORTIONS (1) PROSTATIC PORTION The widest and most dilatable part of the canal and it’s about 3 cm. long
LOCATION Runs almost vertically through the prostate from its base to its apex, lying nearer its anterior than its posterior surface; the form of the canal is spindle-shaped, being wider in the middle than at either extremity, and narrowest below, where it joins the membranous portion.
FUNCTION When distended, it may serve to prevent the passage of the semen backward into the bladder.
<ul><li>MEMBRANOUS PORTION </li></ul><ul><li>the shortest, least dilatable and, with the exception of the external orifice, the narrowest part of the canal </li></ul><ul><li>- measures 3 quarters of an inch along its upper, and half an inch along its lower </li></ul>
LOCATION Extend between the apex of the prostate and the bulb of the corpus spongiosum. It runs downwards and forwards through the urogenital diaphragm. A small portion is passing through the external urethral sphincter.
<ul><li>SPONGY or PENILE or CAVERNOUS PORTION </li></ul><ul><li>- Is the longest part of urethra and travels in corpus spongiosum. </li></ul><ul><li>- It is about 6 inches in length and extends from the termination of the membranous portion to the external urethral orifice. </li></ul><ul><li>- It is narrow, and of uniform size in the body of the penis, it is dilated behind, within the bulb, and again anteriorly within the glans penis, where it forms the fossa navicularis. </li></ul>
FEMALE URETHRA - is a narrow membranous canal, about 4 cm. long in length - it is placed behind the symphysis pubis, imbedded in the anterior wall of the vagina. Ends at the external orifice of urethra, which is the point at which the urine leaves the body. This is located between the clitoris and the vaginal opening
FUNCTION the canal that is only for the passage of urine
BLOOD SUPPLY The female urethra receives branches from the: *internal pudendal arteries *vaginal arteries
The male urethra receives branches from the: *internal pudendal arteries *arteries supplying the prostate. Veins accompany the arteries and have similar names.
NERVE SUPPLY The urethra receives innervation from the pudendal nerve (S2,S3,S4). Afferents from the urethra travel in the pelvic splanchnic nerves.