CPM 281 Genito-Urinary System PDF

12/2/2023 CPM 281 (Basic Anatomy for Pharmacy Students) GENITO-URINARY SYTEM By Pharm Azubuike A. Ekwuofu...

12/2/2023 CPM 281 (Basic Anatomy for Pharmacy Students) GENITO-URINARY SYTEM By Pharm Azubuike A. Ekwuofu Outlines 1. Urinary System  Kidney  Ureter  Bladder  Urethra (male and female urethra) 2. Genital System 2.1. The male system  Testes  Epididymes  Deferent ducts  Ejaculatory ducts  Accessory male genital glands: seminal glands, prostate and bulbourethral glands  Penis  2.2. The female system  Ovaries  Uterine tubes  Uterus  Vagina  External female genital organs: mons pubis, labia majora, labia minora, vestibule of vagina, clitoris, bulbus vestibuli, greater vestibular glands. 1  12/2/2023 The Urinary System Consists of 4 major organs; the kidneys, ureters, urinary bladder and the urethra. The Kidney Vital organs due to their excretory, regulatory and endocrine functions Each weighs about 125–175 g in males and 115–155 g in females. 11–14 cm in length, 6 cm wide, and 4 cm thick Directly covered by a fibrous capsule composed of dense, irregular connective tissue that helps to hold their shape and protect them  Position and relation of the kidney Situated at the posterior abdominal wall on the sides of the vertebral column They extend from the level of TXII(thoracic vertebra XII) to the level of LII – LIII The right kidney is below the liver and, therefore, slightly lower than the left one The superior pole of the right kidney extends to the level of the rib XII, while the superior pole of the left kidney reaches to the rib XI. 2  12/2/2023 Fig 1. The kidneys in relation to the vertebra Internal Structure of the Kidney 3  12/2/2023 Internal Structure of the Kidney cont’d Internal Structure of the Kidney The frontal section an outer region called the renal cortex and an inner region called the medulla. Renal columns are connective tissue extensions that radiate downward from the cortex through the medulla to separate the most characteristic features of the medulla, the renal pyramids and renal papillae. The papillae are bundles of collecting ducts that transport urine made by nephrons to the calyces of the kidney for excretion The renal columns also serve to divide the kidney into 6–8 lobes The bases of the renal pyramids direct to the cortex and outward surface of the kidney. While the apices of the pyramids, renal papillae, project to the minor calices within the renal sinus. 4  12/2/2023 The Renal Hilum The entry and exit site for structures servicing the kidneys: vessels, nerves, lymphatics, and ureters Emerging from the hilum is the renal pelvis, which is formed from the major and minor calyxes in the kidney The artery, vein, and renal pelvis are arranged in an anterior-to-posterior order. The Nephron 5  12/2/2023 The Nephron Functional microscopic unit of the kidney Each nephron consists of the renal corpuscule, proximal, intermediate and distal convoluted tubules The renal corpuscule contains the network or cluster of capillaries (glomerulus) surrounded by a double – layered Bowman's capsule. 6  12/2/2023 The Ureter External description and position of the ureter Ureters are the tubes that transport urine to the urinary bladder (trigone of the bladder) The average length of the ureter is 25 – 32 cm There are three parts of the ureter: abdominal, pelvic, and intramural. In the abdominal part, the ureter is retroperitoneal in position and runs on the anterior surface of the psoas major muscle. The abdominal part is the longest part of the ureter. The intramural part, the part where the ureter pierces the wall of the urinary bladder, is the shortest (1.5 – 2 cm) and the narrowest part Basically, ureter has three constant constrictions 1st at the beginning of the ureter at the pelviureteric junction. 2nd is at the site where the ureter enters the pelvis and crosses the iliac vessels, while 3rd is at the entrance to the urinary bladder in its intramural part. Fig 6 showing the three constrictions of the ureter 7  12/2/2023 The bladder A hollow muscular organ that serves as a temporary reservoir(300 – 400 ml) of the urine. Position and relations of the urinary bladder The empty urinary bladder is completely inside the lesser pelvis, behind the pubic symphysis. Its superior surface is covered by the parietal peritoneum lining the pelvis At filled state, it extends anterosuperiorly (2-4 cm) above the pubic symphysis and in front of the peritoneal cavity directly behind the anterior abdominal wall The trigonal muscle closes the ureteric orifices during the urination (micturition). In male, the internal urethral sphincter (or preprostatic sphincter) completely surrounds the urethra. The function of this muscle is to close the internal urethral orifice in ejaculation and thus prevent the flow of the ejaculate into the bladder, or simply it prevents retrograde ejaculation Empty urinary bladder in the male pelvis. Sagittal section 8  12/2/2023 Full urinary bladder in the male pelvis. Sagittal section The urinary bladder in the female pelvis. Sagittal section 9  12/2/2023 Male Urethra Course and parts of the male urethra 18 – 22 cm long tube that drains urine from the urinary bladder out of the body. It begins as the internal urethral orifice within the fundus (base) of the urinary bladder and ends as the external urethral orifice at the top of glans of the penis Male urethra is subdivided to four parts: intramural (preprostatic), prostatic, membranous and spongy (spongiose) parts. The intramural (preprostatic) part of the urethra passes through the wall of the urinary bladder. It is short (around 1 cm), with a narrow stellate lumen. This part is surrounded by the circular internal urethral sphincter, an involuntary smooth muscle. The prostatic part of the urethra traverses the prostate. It is the widest part of the male urethra. The lumen is C – shaped in the transverse section. The ejaculatory ducts open at the seminal colliculus. The membranous part is a narrow and short part (approximately 3 cm long) that runs through the urogenital diaphragm The lumen of this part has a stellate shape in the transverse section Membranous urethra is surrounded by the external urethral sphincter a voluntary striated muscle, derived from the fibers of the urogenital diaphragm. Male Urethra cont’d The spongy (spongiose) part of the male urethra runs within the bulb of penis and corpus spongiosum of the penis, therefore, sometimes it is called the penile urethra At the bulb of penis, the lumen is slightly dilated into the ampulla (bulbar part of the urethra) In corpus spongiosum, the urethra narrows, and at the end next to the external urethral orifice it widens again to form the navicular fossa The external urethral orifice is located at the top of the glans of penis. It is the narrowest site of the male urethra. The constricted parts of the male urethra are: the intramural (preprostatic ) part, the membranous part, the spongy part (except the navicular fossa and ampulla) and the external urethral orifice is the narrowest site. On the contrary, the dilated portions are the prostatic part, the ampulla and the navicular fossa 10  12/2/2023 Parts of the male urethra. Sagittal section. The Female Urethra Much shorter than the male one Around 4 cm It has a straight ventrocaudal direction in standing position, is directed almost horizontally in lying position Course and parts of the female urethra. The internal urethral orifice is situated at the fundus of the urinary bladder. The female urethra may be subdivided into 4 parts depending on its course: intramural, pelvic, membranous, and perineal part The intramural part runs through the wall of the bladder. It is surrounded by spiral smooth muscle bundles of the internal urethral sphincter. Around the membranous part, the external urethral sphincter, voluntary striated muscle forms a collar. Below the urogenital diaphragm to the external urethral orifice there is the perineal part of the female urethra. The external urethral orifice opens into the vaginal vestibule at the urethral papilla (papilla urethralis) in front of the vaginal orifice and below the clitoris. The lumen of the female urethra in the transverse section is stellate. 11  12/2/2023 Parts of the female urethra. Sagittal section. The Male Genital System The male genital system consists of the internal genital organs: testes, epididymes, deferent ducts, ejaculatory ducts, accessory male genital glands (seminal glands, prostate and bulbourethral glands); and the external male genital organs: penis, scrotum. 12  12/2/2023 INTERNAL MALE GENITAL ORGANS 1. TESTIS male reproductive organs (male gonads) that produce the sperm cells and testosterone. Seminiferous tubules of the testis are the site of spermatogenesis Position and relations of the testis originally developed inside the abdominal cavity but descend to the scrotum during the intrauterine development. The left testis is situated a little lower than the right one. External description of the testis Ovoid in shape and compressed from side to side. The average weight is 10 – 15 g, it is around 4 – 5 cm in length. Internal structure of the testis Immediately below the visceral layer of tunica vaginalis testis, there is the dense collagenous membrane, tunica albuginea. It gives off septula testis that subdivide the testis into the lobules of the testis. There are 250 – 300 lobules in each testis. The lobule of the testis is conical in shape. The lobules of the testis contain the seminiferous tubules. They are usually 80 cm long. In the testis, there are around 500 seminiferous tubules which are the sites of spermatogenesis. The interstitium between the seminiferous tubules contains loose connective tissue with clusters of the Leydig cells that synthetise the testosterone. The spermatozoa are differentiated within the seminiferous tubules and then transported to the head of epididymis. 13  12/2/2023 Testis. Sagittal section. The epididymis Reservoir of sperm cells The sperm cells (spermatozoa) acquire fertilization capability and develop motility potential here. It lies along the posterior border of the testis. The average length of the epididymis is 4 – 5 cm. It consists of the head, body and tail. 14  12/2/2023 Deferent Duct (Vas Deferens) The deferent duct (vas deferens) transports the spermatozoa from the epididymis (the duct of epididymis) to the ejaculatory duct. It is 45 – 50 cm long tube with an external diameter 3 – 4 mm and a lumen diameter around 0.5 mm. Directly above the prostate, the deferent duct unites with the duct of the seminal gland (seminal vesicle, vesiculous gland) creating the ejaculatory duct. The ejaculatory duct traverses the prostate and opens into the prostatic part of the urethra at the seminal colliculus. SEMINAL GLAND (SEMINAL VESICLE, VESICULOUS GLAND) The seminal gland ( seminal vesicle, vesiculous gland) is a paired accessory gland of the male reproductive system. Its secret forms the majority (60-80%) of the ejaculate (semen). The seminal glands are situated behind the urinary bladder and in front of the rectum in rectovesical septum The uppermost parts of the glands are covered by the parietal peritoneum that forms the rectovesical pouch. Along the medial side of the seminal vesicle, the deferent duct descends. Above the seminal gland, there is the ureter. 15  12/2/2023 The seminal gland in relation to the vas deference Prostate The prostate is an unpaired accessory gland of the male reproductive system. Prostatic secretions form up to 1/6 of the ejaculate (semen). The prostate surrounds the male urethra. It is situated below the urinary bladder, in front of the rectum and behind the pubic symphysis (retropubic space). 16  12/2/2023 Zonal anatomy of the prostate. Bulbourethral Gland (Cowper's Gland) a paired exocrine accessory gland of the male reproductive system. It is homologic to the greater vestibular gland in female (Bartholin's glands). Before ejaculation, the bulbourethral glands produce the mucinous fluid that contributes to the lubrication of the urethra for the emission of semen and also neutralizes acidic urine residue in the spongy urethra. 17  12/2/2023 The penis The penis is a male copulatory organ that consists of the root and the body The root of the penis The root is a fixed part of the penis formed by the bulb of the penis and two crura of the penis. The bulb of the penis is a rounded mass of erectile tissue situated between the crura and attached to the perineal membrane. Urethra enters into the bulb through its superior surface. Distally it is continuous with corpus spongiosum in the body of penis. The body of the penis The body of the penis is a pendulous part covered by the skin. It consists of three erectile masses: corpus spongiosum and two corpora cavernosa. Crura of are paired rounded and elongated masses attached to the phallic crest at the inferior pubic rami. Crura of penis distally continue as corpora cavernosa in the body of penis. The dorsum of the penis is formed by the corpora cavernosa, and the urethral surface by the corpus spongiosum that is traversed by the urethra. Corpora cavernosa are two erectile bodies separated by the septum of the penis and enveloped by a common tunica albuginea. Corpus spongiosum (spongy body) is the continuation of the bulb of the penis. Its terminal part is enlarged to form the glans of the penis. The urethra passes through the corpus spongiosum and opens at the top of the glans of the penis as the external urethral orifice. The glans of the penis is conical in shape, overlapping the terminal parts of the corpora cavernosa. 18  12/2/2023 Internal Structure of the Penis Female genital system The female genital system consists of the internal female genital organs: ovaries, uterine tubes, uterus, vagina and external female genital organs: mons pubis, labia majora, labia minora, vestibule of vagina, clitoris, bulbus vestibuli, greater vestibular glands. 19