IM AnSci 111 Module 5 PDF

Module 5 - Urinary and Reproductive Systems MODULE 5 Urinary and Reproductive Systems Intended Learning Outcomes (ILO) At the end of this module, you will be able to: 1. Identify the components of the urinary and reproductive systems 2. Describe th...

Module 5 - Urinary and Reproductive Systems MODULE 5 Urinary and Reproductive Systems Intended Learning Outcomes (ILO) At the end of this module, you will be able to: 1. Identify the components of the urinary and reproductive systems 2. Describe the functions of the organs of the urinary and reproductive systems 3. Describe the processes involve in urine formation 4. Identify the parts of the avian reproductive system 5. Discuss puberty and estrous cycle 6. Discuss the processes involve from fertilization to lactation Recognition of Prior Knowledge 1. True or False? Chickens do not urinate 2. Which among the following is the primary sex organ in females? a. Vagina b. Uterus c. Ovary d. Vulva 3. Which comes first? a. Parturition b. Gestation c. Fertilization d. Lactation 4. What do you call a castrated horse? 5. What is ADH? AnSci 111 - Introduction to Animal Science 24  Module 5 - Urinary and Reproductive Systems CONTENTS Module 5 THE URINARY AND REPRODUCTIVE SYSTEMS The Urinary Systems, 25 Anatomy of the Kidney, 25 Urine Formation, 26 The Basic Functional Unit of the Kidney, 28 Role of ADH in Water Conservation, 30 The Reproductive System, 32 The Female Reproductive System, 32 The Male Reproductive System, 33 The Reproductive Systems of Female and Male Chickens, 35 Puberty and Estrus Cycle, 36 Pregnancy and Parturition, 37 Lactation, 38 Review Questions, 39 Self-Reflect, 40 References, 41 AnSci 111 - Introduction to Animal Science 25  Module 5 - Urinary and Reproductive Systems Content Focus The Urinary System In this module you will learn about the urinary and reproductive systems. These systems have distinct functions however there are some points that organs from these systems merged, thus the term urogenital. In order to have a more focus learning, the urinary system will be discussed first. It is composed of two kidneys, two ureters, a urinary bladder, and a urethra. The urinary system is responsible for maintaining the relatively constant internal environment of the body fluids. This is accomplished by the formation and excretion of urine of an appropriate volume and composition. Urine formation occurs in the kidneys, and by adjusting the volume and composition of urine in response to changes in dietary intake or metabolism, the kidneys regulate the body balance of water, various electrolytes, acids, and bases. The kidneys also excrete metabolic waste products in the urine, including the nitrogenous waste, urea, and a by-product of skeletal muscle metabolism, creatinine. Signs of kidney diseases include imbalances of water, electrolytes, acids, and bases and increases in blood levels of urea and creatinine. Anatomy of the Kidney Kidneys are paired reddish-brown organs, bean-shaped in most animals but heart- shaped in right equine kidney and lobated in the ox (Figure 5.1). The kidneys are located in the dorsal part of the abdominal cavity of each side of the oarta and caudal vena cava, just ventral to the first few lumbar vertebrae. In most domesticated animals the right kidney is slightly more cranial than the left. A tough connective tissue capsule surrounds the entire kidney called the renal capsule. Fig. 5.1 Right kidney of the horse (left), ox (center), and sheep (right). Inside, each kidney features a concavity called the hilus where arteries and nerves enter, and the ureter, veins and lymphatic vessels leave (Fig. 5.2). The origin of the ureter is the renal pelvis. The renal pelvis receives urine from the collecting tubules of the kidney, the AnSci 111 - Introduction to Animal Science 26  Module 5 - Urinary and Reproductive Systems cavity that contains the pelvis is the renal sinus. However, the bovine kidney does not have a renal pelvis, instead the ureter arises directly from the coalescence of individual calyces. Immediately surrounding the renal pelvis is the renal medulla, which appears straited because of the radially arranged collecting tubules. In the addition, the medulla also contains some loops of Henle (descending and ascending loops). The medulla is surmounted peripherally by the renal cortex, in which reside the renal corpuscles, the basic units of filtration. The renal cortex appear to be granular because of the large number of these renal corpuscles; also found in the renal cortex are proximal and distal convoluted tubules and other segments of the loops of Henle. The renal medulla and cortex are arranged in units called lobes, cone-shaped aggregates of renal tissue. The medullary portion of each lobe comprised a renal pyramid, whose apex, the renal papilla, is directed toward the renal pelvis. The renal cortex of the equine, ovine, and caprine kidney lacks visible divisions into individual lobes. The renal papillae are fused in these species into a longitudinal renal crest (Fig. 5.3). The bovine kidney is grossly divided into lobes, each of which communicates with a minor calyx (Fig. 5.3). The porcine kidney lacks external divisions into lobes, but the renal papillae of the medulla distinguish each lobe internally (Fig. 5.3). Fig. 5.2 Internal anatomy of a bean shaped kidney. AnSci 111 - Introduction to Animal Science 27  Module 5 - Urinary and Reproductive Systems Fig 5.3 Internal anatomy of kidney of equine, ovine, and caprine (top left), bovine (top right), and porcine (bottom) Arteries that Supply the Kidneys The blood supply to the kidney is much more extensive than the size of the organ would suggest due to its functions of maintaining the composition of the blood plasma. The two renal arteries may receive as much as one-fourth of the total cardiac output. Each kidney is supplied with blood by a single renal artery which arises from the abdominal aorta. Each renal artery divides the pelvis. These arterial branches pass between the calyxes and penetrate the parenchyma. within the parenchyma, these arteries are designated as interlobar. At the junction of cortex and medulla, the interlobar arteries bend over the bases of the pyramids to form a series of incomplete arches, the acriform arteries. The interlobar arteries arise at right angles from the acriform arteries and run radially toward the periphery in the cortical medullary rays. In their course through the cortex they give rise to short lateral branches, the afferent arterioles, each of which supplies a glomerulus. The Basic Functional Unit of the Kidney The kidneys are composed of thousands to millions of similar microscopic functional units, the nephrons (Fig. 5.4). Nephrons in all mammalian kidneys are similar in basic structure and function, bu the number of nephrons differs among mammals. Large animals have more nephrons per kidney than small animals (e.g. 4 million for cattle and 500,000 for dogs). AnSci 111 - Introduction to Animal Science 28  Module 5 - Urinary and Reproductive Systems Nephrons consist of a spherical structure (Bowman’s capsule) that contains a capillary tuft (glomerulus) and a single long tubule connected to Bowman’s capsule. It consists of two layers of cells. The inner (visceral) layer closely surrounds the glomerular capillaries, and the outer (parietal) layer is continuous with the first segment of the tubule. A Bowman’s capsule with its contained glomerulus is a renal corpuscle. The single tubule is divided into segments based on differences in histological appearance, location in the kidney, and function. These segments are the proximal (convoluted) tubule, loop of Henle, and distal (convoluted tubule). The distal tubules of numerous nephrons connect to another tubular structure found in the kidney, the collecting duct (tubule). Collecting ducts begin in the renal cortex, where they connect with distal tubules, and extend into and through the renal medulla. Fig 5.4 The parts of a nephron. Urine Formation The processes involved in urine formation are the following: 1. Glomerular filtration 2. Selective tubular reabsorption 3. Selective tubular secretion High-pressure blood is supplied to the nephron via a tuft of capillaries called the glomerulus. Most of the contents of the blood except the cells and large protein molecules filter from the glomerulus into the (Bowmans) capsule. This fluid flows down a coiled part of the tubule (proximal convoluted tubule) where useful substances like glucose, amino acids and various ions are reabsorbed. The fluid flows to a looped portion of the tubule called the Loop of Henle where water is reabsorbed and then to another coiled part of the tubule (distal convoluted tubule) where more reabsorption and secretion takes place. Finally, the fluid passes down the collecting duct where water is reabsorbed to form concentrated urine (Fig 5.5). AnSci 111 - Introduction to Animal Science 29  Module 5 - Urinary and Reproductive Systems Fig 5.5 The nephron and the processes associated with urine formation. Role of ADH in Water Conservation Due to the high pressure of the blood and the large pores in the nephron, enormous amount of fluid passes into the kidney tubules which could lead to the animal being drained after 30 minutes. However, most fluid are reabsorbed by the collecting tubules. The Antidiuretic Hormone [ADH] produced by the posterior pituitary gland controls the reabsorption of water in the collecting ducts. If the animal is deprived of water, ADH is released to increase reabsorption of water so that concentrated urine is produced. When the animal drink plenty of water, the release of ADH is put on hold so that no or minimal water reabsorption occurs, diluted urine is then produced. Concentration of the blood is maintained precisely through this mechanism. Ureters, Urinary Bladder, and Urethra The ureter (Fig. 5.6) is a muscular tube that conveys urine from the kidney to the urinary bladder. The smooth muscle of the ureter undergoes peristaltic waves of contraction that encourage the flow of urine to the urinary bladder. Each ureter originates at the renal pelvis (or the major calices of the bovine kidney) and empties into the urinary bladder, the AnSci 111 - Introduction to Animal Science 30  Module 5 - Urinary and Reproductive Systems manner in which the ureter passes obliquely through the wall of the urinary bladder creates a valve to prevent reflux flow of urine to the kidney. The urinary bladder (Fig. 5.6) is a hollow muscular organ that varies in size and position with the amount of urine it contains. The empty, contracted bladder is a thick- walled, piriform organ on the floor of the pelvic cavity. As it fills with urine, it’s wall thins, and it enlarges craniad toward and into the abdominal cavity. The neck of the bladder is continuous with the urethra (Fig. 5.6) caudally. The smooth muscle of the urinary bladder wall is arranged in three sheets; at the neck of the bladder these may form a smooth muscle sphincter that controls passage of urine into the urethra, although the precise role of the intramural muscle of the urinary bladder is not yet agreed upon. The pelvic urethra extends from the urinary bladder across the floor of the pelvic canal to the ischial arch. In female animals, it opens onto the floor of the vaginal vestibule. In the male animal, it receives the ductus deferens and ducts from the accessory sex glands, then passes through the penis as the penile urethra. In both sexes, the pelvic urethra is surrounded by a true sphincter, the striated skeletal m. urethralis, over which the animal exercise voluntary control. The m. urethralis is innervated by the pudendal nerve. Fig 5.6 The kidney and other associated organs in the pelvic cavity. Micturition Micturition is the term for expulsion of urine from the bladder. It normally is a reflex activity stimulated by stretch receptors in the bladder wall that respond to distension of the urinary bladder created by the constant inflow of urine by way of the ureters. The bladder relaxes to accommodate a gradual increase in urinary volume until the stretch becomes great enough to stimulate reflex centers in the spinal cord, AnSci 111 - Introduction to Animal Science 31  Module 5 - Urinary and Reproductive Systems The Reproductive System Two forms of reproduction 1. Asexual – in this process, it does not require the sex organ to facilitate the perpetuation of the species. Unicellular organisms reproduced by fission, while plants is through cuttings or by budding, marcoting or by propagating plant cell in culture media. 2. Sexual - male and female sex organs are involved in the process of propagation. The union of sex cells, ovum, and sperm cell are involved to form a new individual. The Female Reproductive System Ovaries - the principal sex organs of the female Functions: 1. the production of sex cell or ovum; 2. the production of female sex hormone - estrogen The accessory reproductive tract 1. Infundibulum 2. Oviduct 3. Horn of the uterus 4. Cervix 5. Vagina 6. Vulva Fig 5.7 The parts of the female reproductive system. AnSci 111 - Introduction to Animal Science 32  Module 5 - Urinary and Reproductive Systems 1. Infundibulum ٠ It is funnel-shaped structure which picks up the egg when released by the ovary. ٠ It has celia-like structures at the rim of the infundibular funnel which attract the eggs into the infundibulum. 2. Oviduct ٠ Tubular structure connecting the infundibulum to the horn of the uterus. ٠ passage way of the egg on its way to the uterus. ٠ site of fertilization and the beginning of embryonic development after fertilization 3. Horn of uterus ٠ site of implantation for the fertilized egg ٠ the place where fetus would develop during the stage of pregnancy ٠ the two horns are connected by the body to the cervix 4. Cervix ٠ neck of the uterus ٠ os uteri, closes when the animal gets pregnant to protect the uterine contents ٠ serves as sperm receptacle in certain animals 5. Vagina ٠ organ of copulation ٠ serves as sperm receptacle in many species ٠ comprises a part of the birth canal at parturition 6. Vulva ٠ common passageway for the products of reproduction and for urine ٠ comparable to the ventral portion of the cloaca in birds ٠ homologous with scrotum of the male 7. Clitoris ٠ rudimentary organ ٠ homologous to the glans penis of the male 8. Broad ligament Regions of the broad ligament ٠ mesometrium ٠ mesosalpinx ٠ mesovarium AnSci 111 - Introduction to Animal Science 33  Module 5 - Urinary and Reproductive Systems The Male Reproductive System 1. Testes ٠ male generative organ ٠ produces sperm cells in the seminiferous tubules ٠ secrete hormone testosterone in the interstitial cells or cells of leydig ٠ contained in the scrotum; the thermoregulatory organ [NOTE: Failure of the testes to descend into the scrotal sac is referred to as cryptorchidism] Fig 5.8 The parts of the primary sex organ in males. 2. Epididymis It is a long tube connecting the efferent duct of the testis with vas deferens. Consists of head, body and tail Functions: ٠ Maturation of sperm cells ٠ Storage of sperm cells ٠ Passageway for sperm cells ٠ Makes sperm cells concentrated by absorbing some fluids 3. Vas/ductus deferens ٠ connects tail of epididymis to the ejaculatory duct ٠ serves as passageway for sperm cells at ejaculation [NOTE: Vas deferens is only a part of the spermatic cord; cutting of this organ is called vasectomy] AnSci 111 - Introduction to Animal Science 34  Module 5 - Urinary and Reproductive Systems 4. Penis ٠ male copulatory organ, made up of erectile tissues ٠ the free end is protected by a sheath or prepuce ٠ in certain species (e.g. bull, buck, ram and boar), the penis presents a sigmoid flexure which makes it possible for the penis to lengthen. 5. Urethra ٠ found inside the penis ٠ common passage for semen and urine Accessory sex glands: 1. Ampullae – enlargement of the end of vas deferens which contributes fluid to semen (absent in boars). 2. Seminal vesicles – located dorsal to the urinary bladder which add volume to the semen (absent in dogs). 3. Prostate gland – more or less completely surrounding the pelvic urethra which produces alkaline secretions giving semen its characteristics odor (unpaired glands). 4. Bulbourethral or Cowper’s gland - found on each side of the pelvic urethra; its secretion given alkaline reaction that neutralizes and prepares the urethra for the passage of sperm cells. AnSci 111 - Introduction to Animal Science 35  Module 5 - Urinary and Reproductive Systems The Reproductive Systems of Female and Male Chickens Parts of Avian Oviduct Parts of male reproductive system Puberty and Estrus Cycle Puberty – the age of first breeding potential or when gametes are already produced. Estrus cycle – the period from the beginning of one heat to the beginning of the next heat. Types of estrus: Proestrus – the vaginal wall thicken ٠ increased vascularity of the uterine mucosa ٠ maximum follicular growth Estrus – female accepts the male in act of mating ٠ graafian follicles are mature and released from the ovary Metestrus – uterus makes preparations for pregnancy ٠ corpus luteum formation and secretion of progesterone Diestrus – the longest phase ٠ corpus luteum is fully developed (1st part) and regresses if no pregnancy AnSci 111 - Introduction to Animal Science 36  Module 5 - Urinary and Reproductive Systems Average ages or times of reproductive parameters for selected species Fertilization During ejaculation, the male may deposit several hundred million sperm in the vagina, near the cervix. The sperm have a long way to go, however, before one of them encounters an egg. Random swimming takes some sperm through the cervical opening, through the uterus, and up to two oviducts. The journey can take hours or even a day or more. Fertilization occurs when a sperm encounters an oocyte in an oviduct and penetrates the zona pellucida. Some sperm may be viable for up to five days in the female reproductive tract, although most do not last more than two days. Pregnancy and Parturition 1. Pregnancy – is the time in which the female carries her developing young within the uterus (also called gestation) until delivery. The fertilized ovum gets its food from the yolk and uterine secretions (uterine milk) until implantation occurs in the uterus. Implantation varies (e.g. 10-18 d – ewe, 12-24 d – cow and 30-60 d – mare) 2. Parturition – the act of giving birth to young by the mother It is theorized that the growing fetus causes a distention of the uterus and an increased pressure on the cervix, resulting in parturition. Proper hormonal balance is responsible for the onset of parturition. Fetal cortisol production increases which stimulate the placenta to convert progesterone to estrogen. Estrogen stimulates prostaglandin synthesis from the placental membrane and myometrium. Elevation of prostaglandin lowers the threshold to oxytocin, and oxytocin and/or prostaglandin led to myometrial contractility. Prostaglandin destroys the CL thus, cutting off progesterone secretion from the CL. It also stimulates the ovary to produce relaxin. AnSci 111 - Introduction to Animal Science 37  Module 5 - Urinary and Reproductive Systems Stage of labor and related events in farm animals Lactation 1. Lactation or milk production is associated with parturition. 2. Immediately prior to parturition, colostrum synthesis is initiated and the udder begins to enlarge greatly. 3. Milk secretion is a continuous process and is reversible Factors affecting lactation: ٠ Inheritance or genetic constitution of the animal ٠ Secreting tissue (udder size) ٠ Stage and persistency of lactation ٠ Frequency of milking ٠ Age ٠ Animal size ٠ Estrus ٠ Disease ٠ Dry period ٠ Body condition at parturition ٠ Environmental temperature ٠ Feed ٠ Preparation for milking ٠ Stress ٠ Suckling stimulus AnSci 111 - Introduction to Animal Science 38  Module 5 - Urinary and Reproductive Systems Review Questions Matching Exercises (Organ:time) ______1. Magnum a. 90 min ______2. Isthmus b. 15 min ______3. Uterus c. 20 hours ______4. Infundibulum d. 3 hours ______5. Vagina e. few min True or False _______1. The kidneys eliminate excess water from the body. _______2. The cervix closes when the animal gets pregnant. _______3. Cryptorchidism is a condition in which two testicles failed to descend to the scrotal sac during development resulting to sterility. _______4. Ampullae produce alkaline secretions thus rendering the semen’s pH, neutral. _______5. Sperms can live up to 7 days in the female reproductive tract. Fill in the blanks 1. Increase in fetal cortisol production stimulates the placenta to convert __________ to estrogen. 2. __________ and/or ___________ led to myometrial contractility during parturition. 3. _______________ stimulates the ovary to produce relaxin. 4. Unicellular organisms reproduce by ________. 5. _________ is a vasoconstrictor, it reduces medullary and papillary blood flow in the renal interstitium. Identification _______________1. Shape of the horse’s left kidney. _______________2. Artery that the supplies blood to the kidneys. _______________3. Picks up the egg when releases by the ovary. _______________4. Site of implantation of the fertilized egg. _______________5. Common passage of semen and urine. Short Answer (maximum of 30 words only) Is it possible that chickens can lay two eggs in a day? How? AnSci 111 - Introduction to Animal Science 39  Module 5 - Urinary and Reproductive Systems Self Reflect Write what you have learned on this third module. Focus on your knowledge gained, skills to be developed, and proper attitude towards studying nervous and endocrine systems. See you on the next module. Knowledge gained: _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________. Skills to be developed: _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _________________________________________________________________. Attitude towards studying urinary and reproductive systems: _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________ ____________________________________________________________. AnSci 111 - Introduction to Animal Science 40  Module 5 - Urinary and Reproductive Systems References Flanders, F.B. 2012. Exploring Animal Science. Delmar Cengage Learning. Frandson, R.D. Wilke, W.L. and Fails, A.D. n.d. Anatomy and Physiology of Farm Animals. 7th Edition. Wiley-Blackwell. Johnson, M.D. n.d. Human Biology Concepts and Current Issues. 4th Edition. Benjanmin Cummings Publishing. Microsoft ® Encarta ® 2008. © 1993-2007 Microsoft Corporation. All rights reserved. AnSci 111 - Introduction to Animal Science 41