Anatomy Notes Urinary System

Urinary System Kidneys There are two kidneys in the urinary system: - Functions of the Kidney: filters blood, takes out metabolic waste and water, maintains temperature, and can adjust blood pressure - During the development of the kidney, the 3 main structures derive from intermediate mesoderm - The 3 main structures of Embryonic development include: Pronephros, Mesonephros, Metanephros - Pronephros: develops in the 3rd week in cervical area and then disappears by the 4th week - Mesonephros: is developed in the chest, gradually degenerates but parts of the male reproductive organ associates with it - Metanephros: is the permanent and functional kidney in the higher vertebrates; is located in the pelvis - Kidneys are retroperitoneal organs because the left kidney is more superior than the left kidney because of the large liver in the right side of the body; the kidneys are behind the peritoneum that lines abdominal cavity vs other abdominal organs (are in back of the cavity) The parts of the Kidneys include: - The Renal Hilum is the entrance to the renal sinus and contains renal veins, arteries and lymphatic vessels - The Renal Hilum function is to transmit the vessels, nerves, and ureter - Renal veins clear up the kidneys; purified blood goes to inferior vena cava and brings blood back to the heart, they basically drain oxygen depleted blood to the kidneys - The Renal capsule is a thin membranous sheath that covers the outer surface of each kidney which is used to support kidney mass and protect vital tissues; made of tough fibers such as collagen and elastin - The renal capsule is covered in a layer of perirenal fat which is the adipose tissue superficial to the renal fascia - The ureters are on the medial side of the kidneys and is a tube that carries urine from the kidney to the urinary bladder The 3 major regions of the kidney include: - The renal cortex is filled with blood brought in from the renal artery; ultrafiltration occurs here - The renal medulla is white and the inner part of the kidney; splits up into numbers of renal pyramids and contains the structures of the nephrons responsible for maintaining the salt and water balance of the blood - The renal pelvis is to act as a funnel for urine flowing to the ureter - The kidneys produce urine and the ureters, urinary bladder and the urethra act as plumbing system to drain urine from the kidneys, store it, and releases it during urination There are some developmental variations in the kidney: - Ectopic (out of place): a birth defect in which the kidneys are out of place (in abnormal positions) - Horseshoe kidney: is a disorder where the kidneys fuse together to form a horseshoe- shape kidney during development in the womb Microscopic Kidney - There are 1 million nephrons per kidney - Each Nephron filters a small amount the blood - The Nephrons receive blood to be filtered and it is carried out by afferent arterioles - Glomerulus is a tuft of capillaries that produces urine - Urine is carried out a smaller tube called the efferent arteriole and is smaller because there is less blood after - Bowman’s Capsule is from a delicate membrane made of simple squamous epithelium - It performs the first step in filtration of the blood in order to form urine - The part of renal corpuscle where afferent and efferent arterioles are located is known as the vascular pole; On the opposite end of the vascular pole is where the renal tubule begins and is known as the urinary pole. Tubules of the Kidney: - Proximal Convoluted Tubule is super curly (proximal means it's near the glomerulus) and is made of cuboidal epithelium - Fluid in the filtrate enter the proximal convoluted tubule and is then reabsorbed in peritubular capillaries; drains filtrate away from a renal corpuscle - Loop of Henle is a long, U-shaped portion of the tubule that conducts urine within each nephron - The main function appears to be the recovery of water and sodium chloride from the urine - Distal Convoluted Tubule are made of simple cuboidal epithelium; sodium absorption - Collecting Ducts is the last part of a long, twisting tube that collects urine from the nephrons (cellular structures in the kidney that filter blood and form urine) and moves it into the renal pelvis and ureters - There are minor calyces (little cups in the medulla) that collect the urine Nephron Blood Supply: Abdominal Artery →Renal artery →Interlobar arteries →Arcuate arteries →Interlobular arteries →Afferent arterioles →Glomerulus →Efferent arterioles →Peritubular capillaries Interlobular veins →Arcuate veins →Interlobar veins →Arcuate veins →Interlobar Veins → Renal vein →Inferior Vena Cava - Flow= 1 Liter/minute= 20% of total blood volume Urine Pathway: Renal tubules of nephron → Collecting ducts → Papillary ducts → Minor calyces → Major calyces → Pelvis → Ureter → Urinary bladder → Urethra - Urine is formed by thousands of nephrons present inside the paired kidneys and it is passed down the ureters, there from to the urinary bladder. Now how is it formed? - - - Urine is formed when the blood reaches the malpighian corpuscle that is composed of the Bowman's capsule and glomerulus. Here most of the blood plasma is filtered out into the Bowman's capsule. Glomerular filtrate is taken down the proximal convoluted tubule (PCT). Most of the water, glucose and amino acids are reabsorbed here. Active as well as passive reabsorption occurs here. The resulting fluid passes down the loop of Henle . Electrolytes like Na+ and K+ are reabsorbed here. All the absorbed materials enter the peritubular capillaries. The fluid then passes on to the distal convoluted tubule (DCT). Tubular secretion takes place here. This fluid then passes on to the collecting duct where the tissues reabsorb some urea from it. A lot of water gets reabsorbed along collecting duct and urine becomes concentrated. Several such collecting ducts meet to pour their fluids - now known as urine - into the Papillary duct, also known as duct of Bellini . Papillary ducts open at the apex of renal pyramid where urine gets collected in minor calyx, later in major calyx. Calyces open in pelvis , located inside hilum of kidney. Pelvis gives rise to duct like outlet called ureter which travels out of kidney through hilum. The ureter of each side meets the urinary bladder and pours urine into it. When the bladder is full, the stretch receptors come to work and send the signal to brain and we feel the urge to micturate. The outlet that travels from bladder is called urethra . There are sphincters to control opening of urethral opening to void urine outside the body Ureters - There are two Ureters (the upper half of the ureteris located in the abdomen and the lower half is located in the pelvic area): the duct by which urine passes from the kidney to the bladder There are also 3 layers of Smooth muscle: - - - The outer layer, the fibrous coat, is a supporting layer of fibrous connective tissue. The middle layer, the muscular coat, consists of the inner circular and outer longitudinal smooth muscle. The main function of this layer is peristalsis: to propel the urine. he inner layer, the mucosa, is transitional epithelium that is continuous with the lining of the renal pelvis and the urinary bladder. This layer secretes mucus, which coats and protects the surface of the cells. Kidney Stones are hard deposits made of minerals and salts that form inside your kidneys. Often, stones form when the urine becomes concentrated, allowing minerals to crystallize and stick together. Urinary Bladder - The urinary bladder rests on the pelvis cavity floor, posterior to public symphysis of the pelvis - For Males: anterior to the rectum - - - Contraction of this muscle expels urine from the bladder Urinary tract infections (UTI):Bacteria from the large intestine, such as E. coli, are in the perfect position to escape the anus and invade the urethra. From there, they can travel up to the bladder, and if the infection isn't treated, continue on to infect the kidneys. - - For females: anterior to uterus and upper vagina Trigone (three openings)= two ureters and one urethra; The area is very sensitive to expansion and once stretched to a certain degree, the urinary bladder signals the brain of its need to empty. Three layers of smooth muscle: inner longitudinal, middle circular, and outer longitudinal Women may be especially prone to UTIs because they have shorter urethras, which allow bacteria quick access to the bladder. Transitional Epithelial Cell Carcinoma and Smoking: is a type of cancer that typically occurs in the urinary system. TCC arises from the transitional epithelium, a tissue lining the inner surface of these hollow organs. Urethra - - the duct by which urine is conveyed out of the body from the bladder, and which in male vertebrates also conveys semen. Functions: The urethra is the tube that carries urine from the bladder to outside of the body. In males, it has the additional function of ejaculating semen when the man reaches orgasm. When the penis is erect during sex, the flow of urine is blocked from the urethra, allowing only semen to be ejaculated at orgasm. External Sphincter- Voluntary Skeletal Muscle (muscle you exercise) Proper Urination can stop incontinence (weakening of muscle) 3 liters of water a day Color of urination is an indication of hydration Clinical Considerations: - Intravenous Pyelograms is an x-ray examination of the kidneys, ureters and urinary bladder that uses iodinated contrast material injected into veins. Tuberculosis in the Kidney: hypoperfusion and swelling of all or part of the kidney Nephritis: is inflammation of the kidneys High Blood Pressure, Kidney and Heart Diseases are all related: The nephrons in the kidneys are supplied with a dense network of blood vessels, and high volumes of blood flow through them. Over time, uncontrolled high blood pressure can cause arteries around the kidneys to narrow, weaken or harden. These damaged arteries are not able to deliver enough blood to the kidney tissue. - Pockets of urine or cyst are formed in the kidneys (kidney begins to die) Can have blood clots and kill the kidney tissue called infarction - Renal Cancers and smoking: Cancers can occur in the kidney and one cause of cancer starting from the kidneys is smoking tobacco Treatments: - Dialysis is where semipermeable membranes remove wastes and adjust the pH Renal Transplants: can happen while you are living MAle Reproductive System Parts of the reproductive system: FEmale Reproductive System main points notes female reproductive system components: Begins with the gonad.. In female the ovaries Ovaries captured by fallopian tube - Ft has various component - Fimbriae : finger like - Ampulla : flask - Fundus of uterus: dome shaped segment - Bottom = neck = cervix - Below the cervix is the vagina ovaries 1. Paired, produce gametes, suspended by ligaments 2. Ova originally from yolk sac, not “germinal epithelium” of ovary a. Germ cells develop here b. Go through the u cord to the little girl forming the ovaries in the abdominal cavity and stay there c. Embryonic yolk sac = source of ova d. When ovary examined under microscope i. Simple cuboidal epi’m 1. Germinal epi’ 2. Thought this epi = source of the egg 3. NOT GERMINAL// DOES NOT CREATE THE OVA// FOLLICLES 4. Now called superficial epithelium a. Signi of germinal epi// is could be source of cancer// unsure why 3. Approx 300,000 primordial follicles present at birth - Suspended by ligaments/ bands of connective tissue - 1. Medial side: ovarian L’T - - 2. Lateral side/ connecting to pelvic wall: suspensory L’T 3. Extending in diagonally , passes thru inguinal canal: round L’T - Emerges on skin of external genitalia// becoming component of labia majora// ductus deferens of male and round L’t come from same cells embryologically R LT helps situate the system 4. Broad ligament: two layers of parietal/ anterior of ovaries ft and u/ and posterior/ package// all lt’s help orientation primordial follicles Remain in the girl not doing anything Thecal cells = cup cells surrounding the ovum 1. Primordial 2. Primary follicles 3. Secondary follicle = next phase w/ antrum (fluid) 4. Mature Graafian follicles = very large with large antrum and many follicle cells During ovulation the egg burst through the surrounding epi to be released by the epi // when egg gone forms large yellow mass = corpus luteum primordial follicles → primary follicles → secondary follicles → graafian (mature) follicles → corpus luteum (yellow body) producing estrogens and progesterone → corpus albicans (“white body” scar) corpus luteum 1. Cl responsible for estrogen and preguteum a. First several weeks of pregnancy/ later in the pregnancy / or if not fertile i. The cell atrophy and form scar tissue ii. This scar tissue = white mass = corpus albicans iii. corpus luteum forms the corpus albicans (“white body”) either without successful fertilization or at the end of pregnancy (“scar of pregnancy”) ovaries thought to alternate ovulation ● ● ● women are fertile with only one ovary timing of ovulation about every 28 days (may be longer or shorter) ○ Variable in women who have not had their first pregnancy// after first preg much more regulated and predictable Thought the ovaries take turns ○ Sometimes left and sometimes right // that means approx 70 days for each ova// then nearing spermatogenesis time ● follicle development ● Each month several follicles begin to develop, some atrophy, undergo atresia → form atretic follicles ○ Follicles that stop growing and get reabsorbed ○ May cause problems ■ Make form fluid filled pockets// if not reabsorbed// ovarian cysts ● Most of the time unaware// eventually reabsorbed and disappears without difficulty ● Sometime large// then it can be painful and cause fever ● Ovarian cyst pain felt in back// same region as kidney/ the flank area between ab and pelvis ○ Other women in ab or groin ○ Ovarian cancer ■ ■ ● fallopian tubes Cells within the ovary can have abnormal growth Very serious// can undergo metastasis ● Often goes undiagnosed ● No good test for the presence of this cancer// very serious health risk to women About 400 ova are ovulated (10 times/year for 40 years without pregnancy) 1. Paired, extend from the uterus on either side// receive the egg 2. Functions a. Transports egg b. Keeps it moist c. 3. Components a. Fimbriae i. When egg released they literally move and set up flow of current// and bring egg in ii. Dr neilson filmed b. Has cilia//keeps the egg moist Fallopian tubes are the usual fertilization site 1. Takes several days for egg to travel a. Bc it takes so long for egg to travel/ ft most common place for fertilization b. fertilization// sperm enzymes create whole in egg so nucleus of spermatozoa can inject itself 2. Ectopic (out of place) pregnancies a. Outside of uterus b. Fertilized egg grows in fallopian tube // expands tube// abdominal pain//if ignores the child will continue to grow and ft will rupture// after rupture there is tremendous bleeding that occurs/ abdomen will i. Ectopic tubule pregnancy ii. May be necessary to remove ft 1. If removed can still have children bc other ovary untouched 3. Tubal ligation: sometimes reversible a. Tie and cut// type of birth control// female equivalent to vasectomy uterus 1. Function a. One function: facilitate pregnancy// placenta grow in lining of uterus// i. Provides good environment for child and placenta// harbors delivery of hormones 2. Components a. Outer portion = smooth muscle = myometrium i. Very thick wall ii. Contacts rhythmically to create menstrual cramps// sm spasms when woman menstruates // sm expands when woman pregnant// one child delivered uterus goes to pre pregnancy size b. Lining of uterus = endometrium i. ii. Innermost layer 2 components 1. outer/ adj to muscle: never changes 2. Inner lining is shed with each cycle 3. Epithelial cells mixed with blood that has been nourishing this epi a. Permits the lining to be renewed// deeper cells form a new lining// this to offer a nice environment for pregnancy to occur and placenta to form 3. PAP (papanicolaou) smear of the cervix a. Cells from cervix collected harmlessly b. Conducted when small spatula inserted in cervix and scops up some cells// these cells spread on microscope slide and they are examined c. Cells when normal// look exactly the same// same shape/ nice smooth edges// nothing unusual i. Sometimes unusual/ multi nucleus, rough edges 1. Could signal many things: bacterial infections a. Ie syphilis, or gonorrhea, subsequent antibiotics are given 2. Sometime viral infection a. Human papillomavirus (HPV) 3. Fungal infection 4. Yeast infection 5. Changes that indicate precancerous cells// cells don’t look quite right a. Typically once a year, but if look precancerous then conduct another in 3 mos b. Goal = determine cancer early and save life/ metastasis i. If infection to treat promptly 4. Uterine cancers a. 5. Human papillomavirus vaccines a. Higher risk of subsequently getting cervical cancer i. 1 certain type 6. Hysterectomy = removal of uterus// necessary when cervical cancer a. Can be for various reasons i. fibroids// scar tissue masses that occur in uterus// absorbed in lab 1. Connective tissue// can cause a lot of bleeding between menstrual cycles// extensive bleeding// if done having children just take it out ii. Removal of only uterus// not ovaries// why essential to leave = bc hormones necessary and leads to premature menopause iii. You also do not remove the vagina// esential bc sex iv. 7. Fibroids 8. Miscarriage a. Spontaneous loss of unborn child b. Many things can contribute i. Alcohol consumption// is toxic to placenta ii. diabetic// improper control of glucose 1. Diabetes mellitus iii. smoking/ increases the risk iv. Certain drugs 9. Proper birth position: head first, facing backwards a. Head first, face down b. Cervix will dilate c. The mom should be facing the moms spine d. If not in right presentation = breech presentation vagina 1. Components a. Very different from uterus// thin wall of sm // esp cmp to u// strat sq epi, like lining of mouth and skin// lining repairs itself// is not shed during menstruation b. pH is 4.5 // acid end to discourage bacteria// bc don’t want vaginal infection // is corrected during intercourse because spermatozoa wouldn't survive 2. Functions 3. Hymen a. Mucous membrane that covers the opening of the vagina b. Thin covering of vaginal opening// sometimes found in little girls// usually ends up lost i. Not everyone born with it ii. Just disappears not felt, reabsorbed// disappear before menstrual flow iii. Previously believed to be indicator of virginity 1. Bc menstrual flow wouldn’t be possible with hyman 4. Yeast infection//infections do occur// most common yi// discharge with really bad odor// pain during sex/ and itching = symptoms external genitalia 1. Course conspicuous hair grows on the mons pubis a. Mons = soft mound b. Beginning of puberty the hair grows 2. Folds of skin that also develop hair = outer fold = labia majora a. Larger folds, hair at puberty 3. Second folds/ always hairless = labia minora The two labia enclose three structures 1. Clitoris a. Like a penis, contains delicate foreskin, erectile tissue// some countries circumcise clitorise causing hemmhorage b. Circumcision of girls very unnecessary c. Clitoral disease/ infection and cancer extremely rare 2. Female urethra opening below clitoris 3. Opening of vagina below that Floor of women pelvis = perineum 1. In female includes very strong a. Perineal body b. Right between external genitalia and anus c. Must be protected during childbirth d. May stretch during birth and tear// can cause all internal organs to fall i. Surgical procedure performed and perineal body cut by obgyn// ii. episiotomy// when child delivered obgyn stitches this up// give permission in advance menopause Both men and women go through menopause 1. Women stop menstruating breast Before puberty same in boys and girls 1. Nipple and areola In male lactiferous ducts grow in male In female ducts grow like spokes of a wheel 1. Don’t develop very extensively 2. Size and shape due to how much fut present in the region 3. Correlated with how much fat formed in region 4. Nothing to do with chest muscles under the breast 5. 20 or so lactiferous lobules/ mil producing a. When women pregnant these glands grow b. Breast become larger anticipating need for breast milk c. First milk that child receives is very rich in antibodies// first milk of lactation i. First several days essential for providing good immune protection// fewer allergies etc ii. Much better than formula 6. Within breast there are suspensory ligaments = sir astley cooper = coopers sensory ligaments a. Extend into skin like spokes of the wheel// hold breast in proper position b. Sometimes when older the breasts fall//cooper's ligaments weaker i. Pendulous breast c. Import regard to breast cancer// sometimes cooper's ligaments will contract around it and wrinkle the skin// maybe to keep cancer in breast// check if wrinkled // many forms of breast cancer - dangerous thing is that it can spread through lymph nodes // dangerous/ metastasis common