Transcript The Urinary System This system includes the organs that
The Genitourinary System
Chapter 12 1
All the best Santas are furry.
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The Genitourinary System Includes animal reproduction and the processing of liquid waste… 3
The Urinary System This system includes the organs that produce and excrete the waste substance urine.
• • • • These organs are: Kidneys Ureters Bladder Urethra 4
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Feline Urinary System
Female
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The Kidneys (nephro or reno) • Bean shaped organs located on both sides of the vertebral column • Retroperitoneal - Situated outside the peritoneal cavity Renal fasciae surround the kidneys, holding them in • place.
• Hilus – A concave depression on each kidney’s medial • margin Provides an entrance for blood vessels, nerves and the ureter 6
The kidneys are dark reddish brown (except in felines, which are yellowish red). A cross section shows the external cortex and the internal medulla.
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Donor Kidney Transplantation Recipient 8
The Urinary System • Renal sinus – Cavity containing the renal pelvis, blood vessels and fat • Renal pelvis - A reservoir that occupies most of the sinus and funnels urine to thr ureter • Ureter - The outlet tube that connects the renal pelvis & bladder 9
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Medullary pyramids make up the medulla, & stud the walls of the renal sinus. Urine collects through ducts.
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The Nephron The nephron is the functional unit of the kidney, consisting of the renal corpuscle and renal tubule. There are about 1 million nephrons in the kidney.
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The renal corpuscle consists of a double walled cup shaped structure called the glomerular or Bowman’s capsule, which contains a twisted cluster of capillary channels called the glomerulus.
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The Kidney The kidney functions as a filter for waste products in the blood, excreting them in the urine.
These waste products include nitrogenous wastes from the breakdown of proteins, toxins , mineral salts, excess glucose and water.
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Urinary System: The Kidney (Video) http://www.youtube.com/watch?v=zEpUQkQ-uKM 17
Blood Pressure & The Kidneys • The speed that blood filters through the kidneys is affected by blood pressure (BP).
• If systemic BP drops, as in shock, blood filtration may slow to a point where the kidneys stop functioning.
• If BP is too high, kidney damage may result.
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The kidneys affect the rate of secretion of some hormones, synthesize other hormones and maintain the pH of the blood so it remains neutral.
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The Ureters • • • • • Muscular tubes extending from the kidneys to the bladder Walls of the ureters are made up of: An outer fibrous tissue layer Two central layers of smooth muscle Mucous membrane lining 20
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The Ureters • Enter the neck of the bladder obliquely at the trigone • The flow of urine back to the kidney is effectively controlled by a natural valve 22
Urine • Enters the bladder every 10-30 seconds in spurts, rather than a continuous flow • Spurts are produced by peristaltic waves. • Ureteral opening on bladder opens every 2-3 seconds, then closes until another peristaltic wave opens it again • Prevents urine from flowing back into the ureters during bladder contraction 23
The Urinary Bladder • An elastic sac lying in the pelvis • Formed of 3 layers of smooth muscle lined with mucous membrane • Size & position depends on how much urine it contains • Has 2 openings to receive urine from the ureters, and another opening into the urethra 24
The Bladder 25
Cystocentesis 26
At the junction of the neck of the bladder with the urethra is a sphincter muscle that controls the amount of urine that passes into the urethra. The bladder has two • • main functions: Storing urine Excreting urine 27
The voiding of urine from the bladder is called micturition. The act of preventing or concluding urination is a learned and voluntary action in more intelligent forms of animal life.
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The Urethra • A membranous tubular canal that carries urine from the bladder to the exterior of the body • In the female, urethral length varies by species • The exterior opening of the urethra is called the urinary meatus 29
In the female the urinary meatus is located between the vagina and the clitoris directly cranial to the vulva. The only function of the urethra is urination.
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• In the male, the urethra varies in length by species and penile structure.
• It is narrower than the female, so more prone to blockages from urolithiasis (stone formation).
• It extends from the neck of the bladder through the accessory sex glands, between the fascia and through the penis.
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Urinary Catheterization 32
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The Male Urethra Has 3 sections: • Prostatic • Membranous • Cavernous The exterior opening is called the urinary meatus and serves a dual function carrying both urine and reproductive secretions.
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Normal Urine • A clear, pale amber color in most species, with a characteristic odor. • Is about 95% water • Contains dissolved substances such as nitrogenous waste, electrolytes, toxins, pigments, hormones, and abnormal substances like glucose, albumin or blood 35
Average urine output in a 24 hour period • • • • varies by: Species Temperature Water intake Type of work the animal is performing 36
The Reproductive System 37
Male Reproductive Organs • The basic male reproductive organs (gonads) are the testes • The ducts are the epididymides, vas deferentia, ejaculatory ducts and urethra 38
Accessory sex glands (not present in all species) include the seminal vesicles, prostate, bulbourethral and coagulating glands. The penis, scotum and spermatic cord are the primary reproductive structures.
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The Testes • A pair of egg-shaped glands normally located in a sac-like structure called the scotum.
• Size, shape, and location vary depending on species.
• Each testicle is enclosed in a fibrous, white capsule called the tunica albuginea.
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The Testes • • The testes have two functions: Producing spermatozoa Secreting hormones Sperm cells are produced by the .
hormone, testosterone, is secreted by the cells of Leydig.
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• • Testosterone has several functions: Induces/maintains male secondary sex • characteristics Massive head/shoulders, crest of withers, tusks on boars, horns on rams Influences muscle and bone growth 45
Male Female
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Male animals generally have less subcutaneous fat, and the meat is less tender and juicy. Castration is performed on all animals intended for meat production to eliminate accumulation of testosterone after maturity.
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• • • Testosterone also influences: Fluid & electrolyte metabolism Has an excitatory effect on the kidney tubule Suppresses anterior pituitary secretions 48
Epididymus • A pair of tightly coiled tube-like structures • Acts as a place for sperm to mature and stores sperm before ejaculation • Secretes a small portion of the seminal fluid 49
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Vas Deferens • A pair of muscular tubes with diameters that vary by species • A continuation of the tail of the epididymis, and runs through the inguinal canal. • Each is encased in the spermatic cord 51
Vas Deferens • Travels to the bladder and connects with the seminal vesicle to form the ejaculatory duct • Moves sperm from the tail of the epididymis to the ejaculatory duct 52
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Ejaculatory Ducts Two short tubes formed by the joining of the vas deferens with the ducts of the seminal vesicles. They pass through the prostate gland and extend to the urethra.
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Vesicular Glands • Called seminal vesicles in stallions • Two twisted pouches lying along the dorsal and caudal surface of the bladder, ventral to the rectum • Not found in the dog and cat • Secrete the mucid, liquid part of semen 56
Prostate Gland • Made of smooth muscle & glandular tissue • Secretes a viscous, alkaline substance that makes up most • of the seminal fluid This alkalinity protects the sperm 57
Spermatic Cords - White fibrous tissue encasing the vas deferens, blood and lymph vessels and nerves • • • Scrotum: Saclike structure that houses the testicles Separated internally by scrotal septum Regulates testicular temperature 58
Penis • Made of three rounded masses of erectile tissue encased in a fibrous capsule • Contains the urethra, which carries both reproductive secretions and urine 59
Female Reproductive Organs • • • • Ovaries: Caudal to the kidneys Each is connected to the uterus by a ligament Formed by a single layer of cells The interior consists of a network of connective tissue where the follicles are embedded, and these contain the ova.
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• The functions of the ovaries are • ovulation and hormonal secretion: Estrogen induces female characteristics and uterine preparation.
Progesterone prepares the uterus to receive the fertilized ovum 61
Fallopian Tubes (ovaducts) • Consist of an inner ciliated mucous membrane layer, a middle smooth muscle layer and outer layer of serous tissue • Act as ducts to the uterus for the ova • Fertilization usually takes place here 62
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Uterus (metro, hystero) A thick-walled hollow organ made up of the: • • • Body (corpus) Cervix (neck) Two horns (cornus) 64
Uterus • • • Uterine walls are made of three layers: Endometrium (inner) Myometrium (middle) Perimetrium (external) The perimetrium is continuous with a band of the peritoneum known as the broad ligament.
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• • • The uterus has several • • functions: Accepts fetus Specialized structures for attachment of placenta Produces uterine milk to nourish embryo before implantation Maintains & supports developing fetus Contracts to move fetus into birth canal 67
The Cervix • Composed of smooth muscle arranged in a ring-like structure called a sphincter • Prevents foreign bodies from entering • • the uterus during gestation Tightly closed except during estrus, when it relaxes to allow sperm to enter. During pregnancy, the cervix is filled with a mucus plug.
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The Vagina • An elastic tube lined with a mucous membrane • Before sexual maturity the external vaginal orifice may be occluded by a fold of mucous membrane called the hymen.
• Acts as a sheath to accept the penis during copulation • Provides passage for uterine secretions and the neonate during pregnancy 70
The Vulva The vulva consists of the vaginal orifice, vestibular glands, clitoris, hymen, and the urethral orifice. 71
Mammary Glands • Milk-producing glands composed of connective and adipose tissue • Milk secreting cells (alveoli) form larger ducts called the udder cistern, which transport milk to the base of the teat.
• Milk production is stimulated by the lactogenic hormone prolactin. • The emptying of milk secreting tissue is caused by the hormone oxytocin.
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Roxy’s Puppies: 6 Days Old Other Videos: 3 ½ weeks: http://www.youtube.com/ watch?v=OsDVPF7xdUw 6 ½ weeks: http://www.youtube.com/ watch?v=oF-apbLoDsc 9 ½ weeks: http://www.youtube.com/ watch?v=lbXTayxEwIg http://www.youtube.com/watch?v=h1-fIs6eyBM 73
The Estrous Cycle • The estrous cycle prepares the uterus to receive a fertilized ovum. • At the beginning of the cycle, ova within the follicles in the ovaries develop until they reach ripened follicle size (graafian follicle).
• One or more of these graafian follicles eventually rupture and the ovum is expelled into the uterine tube.
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Ovulation usually occurs during estrus, when the animal is said to be in heat. The ruptured follicle grows larger and fills with a yellow lipoid material before becoming the corpus luteum.
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Most animals are considered spontaneous ovulators, with cyclical heats. Some animals are considered induced ovulators, meaning ovulation occurs after copulation (cats, rabbits, ferrets, llamas, minks).
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• • • The corpus luteum secretes progesterone.
If fertilization occurs, the corpus luteum continues to secrete progesterone and prevent future estrous cycles during pregnancy. If fertilization does not take place, the corpus luteum and its secretions diminish forming a corpus albicans.
Reduced hormone levels will lead to a new estrous cycle.
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Stages of Estrous The estrous cycle has four phases: • Proestrus • Estrus • Metestrus • Diestrus And, in some species, anestrus.
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Proestrus • The “building up” phase • Follicle stimulating hormone (FSH) is secreted by the pituitary gland, causing the follicle to develop within the ovary. • FSH stimulates the ovary to release increased estrogen, which causes changes to the vagina, uterus, oviducts and ovaries.
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Estrus • Period of sexual receptivity • Ovulation occurs • FSH levels decrease and luteinizing hormone (LH) increases causing the ripened follicle to rupture (ovulation).
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Metestrus • The postovulatory phase • The corpus luteum forms and produces • progesterone, while estrogen levels decrease. Progesterone is responsible for proper implantation, and maintaining pregnancy. • If pregnancy does not occur, the corpus luteum decreases in size to a corpus albicans.
• Can be followed by pregnancy, false pregnancy, diestrus, or anestrus.
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Approaching Parturition 82
Diestrus & Anestrus • Diestrus is a short inactive phase before the onset of the next proestrus in polyestrus animals • Anestrus is a period of sexual inactivity. Canines are in estrus twice a year and have long periods of anestrus between cycles 83
Pregnancy • The period between conception and parturition • After fertilization, the ova moves from the uterine tube to the uterus • Until implantation the organism is called an embryo. • After implantation the organism is called a fetus. • The placenta is the only connection between the dam and the fetus.
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Gestation periods vary: bovine: 280 days equine: 336 days caprine, ovine: 150 days porcine: 114 days canine and feline: 63 days 85