the urogenital system

TheUROGENITAL

SYSTEM

Objective:By the end of this report, the students will be

able to:

• List down the important functions of the urinary and reproductive system.

• Describe the location, structure, and parts of the urinary and reproductive system.

• Trace the anatomical path taken by urine.• Explain the events that occur during meiosis:

spermatogenesis and oogenesis.• Explain the effect of hormonal activities to the

concentration of urine; and to the changes in male and female during puberty.

The URogenital System

I. Functions of the Excretory SystemII. Animal OsmoregulationIII. Excretory System

a. Phylogeny & DevelopmentIV. Human Excretory System

a. Kidneyb. Nephrons; Ducts; and Bladderc. Urine Formation:

Glomerular Filtration,Tubular Reabsorption and Secretion

d. Urine Movemente. Regulation of Urine

Concentration andBalance

VI. Functions of Reproductive SystemVII. Animal ReproductionVIII. Reproductive System

a. Development and Variations

IX. Human Male Reproductive Systema. Penis and Scrotumb. Accessory Glandsc. Spermatic Ductsd. Testes 1. Spermatogenesise. Hormonal Regulation

X. Human Female Reproductive Systema. Vagina and Vulvab. Oviducts and Uterusc. Ovaries 1. Oogenesisd. Hormonal Regulation and Menstruation

Anterior view of the Urogenital System.

FunctionsThe Kidney and Homeostasis

1. The kidneys excrete metabolic wastes such as urea.2. Maintenance of water-salt, which in turn affects blood volume and blood pressure3. Maintenance of acid- base balance

Other parts1. Ureters transport urine2. Urinary bladder stores urine3. Urethra passes urine to outside

Animal Osmoregulation

Osmoregulation- (electrolyte homeostasis) the general term for the processes by which animals control solute concentrations and balance water gain and loss.

Osmoconformers- (mostly marine animals)which match their body osmolarity to their environment actively or passively.

Osmoregulators-  actively control salt concentrations despite the salt concentrations in the environment.

• Stenohaline (stenos- narrow; halos- salt)- organisms cannot tolerate a wide fluctuation in the salinity of water.

• Euryhaline (eurys- broad; halos- salt)-  organisms are able to adapt to a wide range of salinities.

In most animals, osmoregulation and metabolic waste disposal rely on Transport epithelia - one or more layers of epithelial cells that specialize for moving particular solutes in controlled amounts and in specific directions.

Body fluid regulation of bony fishes. Marine bony fishes employ different mechanism compared to freshwater fishes in order to osmoregulate their body fluids.

Aquatic Animals

(b.) Freshwater Fishes

(a.) Marine Fishes

Adaptation of aquatic birds to a high salt environment

Terrestrial Animals

The salt glands found above the eye sockets of the skull act as a second pair of kidneys in a way as they desalinate water.

To the right, a Marine Iguana. Below, a Leatherback Sea Turtle.

In marine turtles, the salt gland is a modified tear (lacrimal) gland, and in sea snakes, a salivary sublingual gland beneath the tongue gets rid of excess salt. Sharks' glands are found in their rectum, birds' and reptiles' in or on the skull in the area of the eyes, nostrils or mouth.

Chacoan waxy monkey frog (Phyllomedusa sauvagii); adapted to hot and arid conditions, has excellent kidneys to recycle water, this species secretes a waxy lipid which it wipes over its skin to prevent desiccation.

A Kangaroo rat.

Nitrogenous Waste Products

• Ammonia - Amino groups removed from amino acids immediately form ammonia (NH3) by the addition of a third hydrogen ion-Toxic and can be an excretory product if a good deal of water is available to wash it from the body

• Urea - production requires the expenditure of energy because it is produced in the liver by a set of energy-requiring enzymatic reactions-Less toxic than ammonia and can be excreted in a moderately concentrated solution, conserving water

• Uric Acid - synthesized by a series of enzymatic reactions that requires expenditure of even more ATP than urea-Uric acid is routinely excreted by insects, reptiles, and birds

Excretory System

Nephridia- general term for animal excretory organs; they consist of nephridial tubules.

Protonephridia- which inner ends are closed by ciliated/flagellated cells (Flame cell, if ciliated; Solenocyte, if flagellated).

Phylogeny of Nephridial tubules

Metanephridia- which inner ends open into coelom by a ciliated funnel.

Malpighian tubules of: above, cockroach (indicated by yellow arrow) ; right, bee

Archinephros (holonephros)- earliest vertebrate kidneys probably extended the entire length of the body cavity & had external glomeruli.

Development of Kidney and Ducts

Fate of Nephrogenic MesodermThe diagram shows the development of the urinary system. Also, the animals where these are found.

• Pronephros (-nephroi pl. form) - develops from the most anterior part of mesomere/nephrotome over a limited, usually small, number of segments.

Mesonephros (Opisthonephros in anaminiotes)- develops in the mesomere immediately or shortly behind the pronephroi.

Urogenital organs of male salamander.

• Metanephros- third nephridia of vertebrates, found only in amniotes. The collecting system develops from an outgrowth put out from the mesonephric duct near its entrance into the cloaca.

• Urinary Bladder- a sacciform evagination from the ventral cloacal wall.

- in fishes, when present, bladder is formed by the enlargement of terminal portions of mesonephric duct.- urinary bladder of amphibians is a thin large ventral outpocketing of the cloaca- in amniotes, there’s enormous cloacal evagination called allantois. Adult bladder forms at the base allantoic stalk.- birds lack urinary bladders.

Human Kidney

• Bean- shaped pair of organ, about the size of a tightly clenched fist.

• Lie posterior to the abdominal wall. Left kidney is nearer to midline and to diaphragm than the right one.

Posterior relation

• Ribs- 11and 12 for left and 12th for right• Muscles- 3 muscle

a. Psoas majorb. Quadratus luborumc. Transversus abdominis

• Nerves- 3 nervesa. Subcostal nerveb. Iliohypogastric nervec. Ilio-inguinal nerve

• Diaphragm

Coverings of the Kidney• Fibrous capsule ( true capsule)• Perinephric fat• Renal fascia( fascia of Gerota)

a. Fascia of Toldtb. Fascia of Zuckerkendl

• Paranephric fat

The functional unit of the kidney is the nephron

The glomerulus is composed of capillaries with pores. The inner layers of Bowman’s capsule consists of specialized cells called podocytes.

The cross section of renal cortex (right), it is composed of nephron limbs and ducts; the glomerular capsule; and venules and arterioles.

• Scheme of filtration barrier (blood-urine) in the kidney. A. The endothelial cells of the glomerulus; 1. pore (fenestra).B. Glomerular basement membrane: 1. lamina rara interna 2. lamina densa 3. lamina rara externaC. Podocytes: 1. enzymatic and structural protein 2. filtration slit 3. diaphragma

The c.s. of Renal Medulla showing the:

Thin Descending LimbsThick Ascending Limbs

Juxtaglomerular Apparatusa. Macula Densa- sensitive to NaCl concentrationb. Juxtaglomerular Cells- made up of smooth muscle cells, responsible for production of reninc. Extraglomerular Cells- (a.k.a. Lacis/ Goormaghtigh/Polkissen Cells)

associated with the secretion of erythropoietein

The inner lining of the ureter, urinary bladder and urethra are transitional epithelia and layers of connective tissues.

Micturition- discharge of urine from the bladder.

Micturition Reflex- contraction of the urinary bladder stimulated by stretching of urinary bladder walls.

Regulation of Urine Concentration and Balance

Hormonal Mechanisms1. Antidiuretic Hormone (Posterior Pituitary Gland)2. Renin- Angiotensin- Aldosterone3. Atrial Natriuretic Hormone (Right atrium of heart)4. Parathyroid Hormone-Calcitonin

Sympathetic Innervation

FunctionsReproductive System

1. The main function is to make sure that a specie survives by producing new offspring.

Male R. S.1. Production of sperm cells2. Sustaining and transfer of sperm

to the female3. Production of male hormones.

Female R. S.4. Production of egg cell.5. Reception of sperm cells from

male.6. Protecting and nourishing

offspring/s until birth.7. Production of female hormones.

Animal Reproduction

• Animals have evolved to a large number of strategies, both asexual and sexual, for producing offspring.

• Asexual Reproduction- generation of new individuals, from a single parent, without fusion of gametes (egg and sperm). Offspring is genetically identical to parents.

• Sexual Reproduction- a two parents give rise to offspring that have unique combination of genes inherited from both parents

• Fission- separation of a parent individual to a two individuals of approximately equal size.

• Budding- new individuals arise from an outgrowth of existing ones.

• Fragmentation & Regeneration- breaking and regrowth of body parts.

Parthenogenesis- is an asexual reproduction in which an egg develops without being fertilized.

Animal Reproduction

Vertebrates exhibit sexual reproduction. Zygote results from the union of male and

female gametes. Ova and spermatozoa are produced in the

gonads, the testes and ovaries respectively. Gonads are derived from the mesoderm. Deferent ducts in male, and oviducts in

female transport gametes to the outside of the body.

• Ovuliparity- fecundation is external. E.g. Fishes and some amphibians.

• Oviparity- syngamy is internal, the female lays zygotes as eggs with large vitellus. E.g. Birds

Modes of Reproduction

• Oviviparity- fertilization is internal with retention of zygotes in the female’s body or in the male’s body E.g. Hippocampus and Gymnophiona and some reptiles.

• Viviparity- conception and development occurs inside the female’s body until offspring/s can independently live.- Histotrophic- the zygotes develop in the

female’s oviducts, but find their nutriments by intrauterine cannibalism (E.g. Sharks)

- Hemotrophic-  nutrients are provided by the female (E.g. Placental mammals)

• Hermaphroditism- an individual has both the male and female reproductive system.

-Sequential Hermaphroditism†Protandry†Protogyny, †Bidirectional Sex Changer

-Simultaneous Hermaphroditism-Pseudo- hermaphroditism

Reproductive SystemDevelopment and Variations

Gonadal primordia

Gonads arise as a pair of embryonic genital ridges, which are the thickenings of the coelomic mesothelium medial to the mesonephroi

• Lateral to the undifferentiated pair of gonad is two parallel pair of ducts. The Wolffian Duct and the Mullerian Duct

In both males and females the cloaca becomes separated into the anterior urogenital sinus and posterior rectum by a urorectal septum. 

Elasmobranchs’ testes

• Paired symmetrical structures

• Suspended by mesorchium

• Other fishes have elongated and lobulated testes.

Amphibian testes

• Shape corresponds to body shape

• Elongated in caecilians, short or irregular in urodeles

• Oval or rounded and more compact in anurans

Reptiles’ testes• Oval rounded or pyriform compact

structures• Snakes’ and lizards testes’ have one

testes that occupies farther forward in the body cavity than the other

Birds’ testes

• Oval or round-shaped and changes in size depending on the period of the year.

Mammalian testes

• Tunica albuginea a thin tough fibrous envelop of the testis

• Vaginal sac is a diverticulum of the peritoneum into the scrotum

• Tunica vaginalis is the extension from vaginal sac that comes in close contact with the tunica albuginea

• Vary in vertebrates and are several times smaller than the ova

• All possess tails for locomotion

• Number produced by the human male is about 4ml or 300 million per ejaculation

• Boar produces about ½ liter

Spermatozoa

Male genital ducts

• Some fishes (e.g., gar & sturgeon) & amphibians - mesonephric duct transmits sperm & urine

• Some amphibians - mesonephric duct transports only sperm; new accessory urinary duct drains the kidney

Male genital ducts• Sharks - mesonephric

duct is used primarily for sperm transport; accessory urinary duct develops

• Teleosts - mesonephric duct drains kidney; separate sperm duct develops

• Amniotes - embryonic mesonephric ducts transport sperm in adults

Alosa fallax (Female)Illustration of a hen genital tract and the eggs.

Table: Comparison of Animal Ovaries

Animal Description

Fishes Cyclostome, chondrichthyes, dipnoans and some primitive ray-finned fishes have a solid but less compact ovary.

Adult teleost have hollow and fused ovaries

Amphibians One or several large lymph space is present within the ovary. Stroma is absent and it is pleated. Ripening eggs hang in the central cavity.

Reptiles Solid and compact with relative much stroma,

>however, snakes’ and lizards’ ovaries are saccular and elongated. Lutea corpora forms in certain species.

Aves >however, birds’ right ovary degenerates, and the left becomes the functional gonad. Cicatrix forms when mature ova escapes the ovarian follicles.

Mammals >however, mammalian ovaries have space within each maturing follicle. Antra is the only cavitation present in egg follicle.

Frog

Shark

Table: Comparison of Female Ducts of Animals

Animal Description

Fish

Narrow distensible oviduct on either side. Elasmobranchs have ostium tubae, which opens into the

coelom. Shell gland is an enlargement of the oviduct.

Amphibian Paired, elongated tubes with ostia, line with cilia. Enlarged posteriorly to form a short uterus or uterine

enlargement . Uterus opens independently into the cloaca. Uteri in most amphibians serve for temporary storage for ova.

Reptiles Open into the coelom through slit-like ostia. Turtles and crocodilians have glands in the upper part that

secrete albumen. Shell is deposited in the uterus or shell gland in snakes and

lizards. Uteri enter cloaca independently.

Hen

Table: Comparison of Female Ducts of Animals

Animal Description

Aves Most, except birds of prey, have only the left oviduct that is functional.

Long, coiled, and consists of several regions. Ostium is bordered by fimbriae. Albumen is secreted by the glandular portion.

Mammals

Paired, with various degrees of fusion between the two sidesDivided into three regions: Oviduct, uterus and vagina.4 uterine variationa. Duplexb. Bipartitec. Bicornuated. Simplex

a. Two completely separated uteri and two vagina.b. A uterus with two horns and two totally separated passageways within the

body of uterus.c. A uterus with two horns and a single passageway within the body of

uterus.d. No uterine horns and the vagina opens directly into the body.

Human Male Reproductive System

Human Penis

The penis consists of a root, body, and glans.

• It is composed of three cylindrical cavernous bodies of erectile

• tissue: the paired corpora cavernosa dorsally and the

• single corpus spongiosum ventrally.

Scrotum

• A sac-like structure containing the testes

• Beneath the skin is a layer of of smooth muscle called dartos muscle.

• Another muscle is found inside: the cremaster muscle

Accesory Glands

• Prostate Gland- surrounds the urethra and ejaculatory ducts immediately inferior to the urinary bladder. The thin, milky secretion of the prostate constitutes about 30% of the semen.

• Seminal Vesicle- are a pair of glands posterior to the urinary bladder. Contribute a viscous yellowish fluid, the last component of the semen to emerge.

• Bulbourethral (Cowper’s) gland- are named for their position near a dilated bulb at the inner end of the penis. They produce a clear slippery fluid that lubricates the head of the penis

• Efferent ductules- carry sperm to the epididymis. Duct of the epididymis- a site of sperm maturation and storage.

• Ductus deferens- It passes upward through the spermatic cord and inguinal canal and enters the pelvic cavity.

• Ejaculatory duct- where the ductus deferens and duct of the seminal vesicle meet. It passes through the prostate gland and empties into the urethra.

• Testes- are oval organs within the scrotum.

• Combined endocrine and exocrine glands that produce sex hormones and sperm.

• Vagina- long fibromuscular canal lined with mucous membrane that extends from the exterior of the body to the uterine cervix.

Human Female Reproductive System

• It allows for the discharge of menstrual fluid, receipt of the penis and semen, and birth of a baby.

• Vulva- consisting of the vestibule and the surrounding structures. Two glands maybe found in each side of the vestibule the:*Lesser Vestibular Gland*Greater Vestibular Gland

• Oviducts (salpinges)- are canals about 10 cm long leading from each ovary to the uterus, at the distal ovarian end is the infundibulum, with finger-like projections.

• Uterus- - is a thick muscular chamber that opens into the roof of the vagina and usually tilts forward over the urinary bladder.

• Its function is to harbor the fetus, provide a source of nutrition, and expel the fetus at the end of its development.

• Ovary- - produce egg cells (ova) and sex hormones.

• The ovary is an almond- shaped organ

Puberty