The Reproductive System. Presenter: Dr. Jim Hurrell

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1 The Reproductive System Presenter: Dr. Jim Hurrell

2 A Warm Welcome from My Faculty TEAM and Me!!! 2

3 The Pledge of Allegiance 3

4 Veterinary Technician/NURSE Oath 4

5 5

6 Come Hang Out with Us in Our Awesome Facebook Group! 6

7 The Reproductive System 7

8 Putting Things in Perspective! ANIMAL REPRODUCTION 8

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10 Canine Behavior? 10

11 Feline Behavior? Client Behavior? 11

12 Comparative Reproductive Anatomy 12

13 Ever Happen to You? 13

14 Why Are There So Many Rabbits??? 14

15 Aren t Genetics and Reproduction FASCINATING??? 15

16 Like Rabbits? 16

17 Comparative Reproductive Physiology Theriogenology 17

18 Anybody Know What She Is Doing? 18

19 Prolapsed Uterus? 19

20 Ovariohysterectomy (OHE) Uterine Horns 20

21 What Is This? 21

23 Overview Sexual Reproduction WHY SEX? ASEXUAL VS. SEXUAL REPRODUCTION MITOSIS VS. MEIOSIS SPERMATOGENESIS VS. OOGENESIS 23

24 Why Sex? Survival of the species All other body systems are about the survival of the individual animal Economic system for agricultural species Dairy Beef Equine (horse racing) Pork 24

25 Asexual vs. Sexual Reproduction Asexual reproduction massive numbers of offspring in short period of time, all organisms with same DNA Bacteria, protozoans, cloning Sexual reproduction fewer numbers of offspring, all organisms with different DNA Increased genetic diversity (larger gene pool) Increased survival of the species Most multicellular organisms 25

26 Animal Reproductive System Physiology Works to ensure survival of the species of the animal Interacts with other body systems Purely reproductive structures are not essential to the life of an animal Requires a second animal (of the opposite sex) to fully carry out its function Process begins with fertilization Head of spermatozoon must penetrate into the cytoplasm of ovum 26

27 Chromosomes Coiled masses of DNA in the nuclei of cells Each cell in an animal's body (except spermatozoa or ova) contains paired, identical chromosomes Diploid chromosome number = 2n Total number of chromosomes in the nucleus of each body cell is the same (except for reproductive cells) Always an even number chromosomes occur in pairs. 27

28 Sex Chromosomes Designated as either "X" chromosomes or "Y" chromosomes If both of the sex chromosomes are X chromosomes (XX), the individual is genetically female If one is an X and the other is a Y (XY), the individual is genetically male 28

29 The Genetics of Sex 29

30 Mitosis vs. Meiosis Mitosis diploid chromosome number (2n) Production of all cells in body except gametes Meiosis haploid chromosome number (n) Production of gametes (sex cells) Fertilization Sperm (n) + ovum (n) = = zygote (2n) 30

31 Cell Division Mitosis = 2n Each chromosome produces a duplicate copy of itself Half of chromosomes go to one daughter cell, and half go to the other Genetic makeup exactly the same as each other and as the parent cell Meiosis = n Chromosomes do not produce duplicate copies before daughter cells pull apart Random half of total chromosomes go to each daughter cell 31

32 Diploid Chromosome Numbers 32

33 Mitosis INTERPHASE PROPHASE METAPHASE ANAPHASE TELOPHASE 33

34 Mitosis Most body cells divide after the cell first makes a duplicate copy of its chromosomes Half the chromosomes go to one daughter cell and half go to the other Genetic makeup of the two daughter cells is exactly the same as each other and as the parent cell 34

35 Mitosis Overview 35

36 Mitosis Summary 36

37 Mitosis Review Again 37

38 Meiosis SPERMATOGENESIS OOGENESIS 38

39 Meiosis Cell division that produces basic reproductive cells Ova Spermatozoa Process ensures that the genetic makeup of each new animal is unique 39

40 Meiosis Creation of reproductive cells (gametes) Sperm & egg Occurs in gonads (sex organs) Diploid (2n) number haploid (n) number Meiosis I Tetrads Crossing over Meiosis II Like mitosis 40

41 Meiosis I & Meiosis II 41

42 Meiosis The Entire Story 42

43 Haploid Chromosome Number The reduced number of chromosomes in the gamete Results from a reduction division (meiosis) Cell divides Total number of chromosomes in each daughter cell is reduced to ½ number of the parent cell Ensures that fertilized ovum from union of ova and spermatozoa has the diploid number 43

44 Meiosis Gamete Formation Diploid number haploid number of chromosomes Spermatogenesis in male animal 1 spermatogonium 4 mature sperm Oogenesis in female animal 1 oogonium 1 mature egg (ovum) + 3 polar bodies 44

45 Spermatogenesis The process where spermatozoa (male gametes) are produced in large numbers in the seminiferous tubules of the testes 45

46 Spermatogenesis Primary spermatocyte divides by meiosis into secondary spermatocytes haploid number The secondary spermatocytes divide by mitosis into four spermatids Spermatids grow tails and undergo other physical changes that convert them to spermatozoa. 46

47 Spermatogenesis When the spermatozoa are fully developed, they detach and are carried to the epididymis for storage before ejaculation Half of the spermatozoa produced have an X sex chromosome, and half have a Y sex chromosome The male sperm determines the sex of the offspring! 47

48 Oogenesis The process where ova (female gametes) are produced (a few at a time) in the follicles of the ovaries Female has fixed number of primary oocytes at or soon after birth 48

49 Oogenesis Primary oocyte divides by meiosis into a large secondary oocyte and a small "polar body" Each has the haploid chromosome number Secondary oocyte and the first polar body divide by mitosis into an ovum and three polar bodies 49

50 Comparing Spermatogenesis & Oogenesis Spermatogenesis Oogenesis 50

52 Male Reproductive System 52

53 The Male Reproductive System The testes are the male gonads The male reproductive cells are formed in the testes Testes located outside body in the scrotum 53

54 Canine Reproductive System Bassert Lab Manual 54

55 Male Reproductive System Physiology Produces male sex hormones Develops spermatozoa Deliver the spermatozoa to the female system at the appropriate time 55

56 Trace a Sperm Cell (Bovine) 56

57 Comparative Anatomy (Canine) 57

58 Comparative Anatomy Male Dog & Cat 58

59 Scrotum Cremaster muscle Tunica albuginea Testicles (testes) Epididymis Spermatic cord Ductus deferens (vas deferens) Testicular vessels Male Reproductive System Bassert Lab Manual 59

60 Scrotum Sac of skin that houses the testes Helps regulate temperature of testes Testes must be kept slightly cooler than body temperature Cremaster muscle passes down through the inguinal ring and attaches to the scrotum. Adjusts the position of the testes relative to the body depending on temperature 60

61 Canine Scrotum Bassert Lab Manual 61

62 Tunica Albuginea (White Coat) 62

63 Fibrous connective tissue capsule that encloses each testis Septa divide each testis into tiny lobules that contain the seminiferous tubules Tunica Albuginea 63

64 Produce sperm and hormones Located outside the abdomen in the inguinal region Housed in a sac of skin the scrotum Testes (Testicles) 64

65 Seminiferous tubules Produce sperm (spermatogenesi s) Interstitial cells (Cells of Leydig) Produce testosterone Histology of Testicle 65

66 Site of spermatogenesis Seminiferous Tubules Long, convoluted U-shaped tube attached at both ends to system of ducts (rete testis) Interstitial cells endocrine cells between the seminiferous tubules -produce androgens Sertoli cells Support developing spermatids 66

67 Seminiferous Tubules spermatogenesis takes place in U-shaped tube = rete testis interstitial endocrine cells produce androgens Sertoli cells support developing spermatids and shield from body s immune system 67

68 Seminiferous Tubules 68

69 Testicle Development Develop just posterior to kidneys Descends into scrotum by passing through inguinal canal Gubernaculum (cordlike structure containing muscle) extends from the testicle to the inner lining of scrotum It shortens, and guides the testicle to the scrotum 69

70 Descent of Testes 70

71 Functions of the Testes Spermatogenesis Spermatozoa are produced in seminiferous tubules of the testes Hormone production Androgens (male sex hormones) produced in interstitial cells of the seminiferous tubules Principal androgen = testosterone 71

72 Spermatozoa Structure HEAD MIDPIECE TAIL 72

73 Sperm Structure 73

74 Spermatozoa Long, thin cells 3 main parts Head Covered by caplike acrosome Midpiece Tail 74

75 Contains nucleus Covered by acrosome Contains digestive enzymes that help spermatozoon reach and penetrate ovum Head 75

76 Midpiece Large concentration of mitochondria arranged in a spiral pattern 76

77 Tail Contains muscle-like contractile fibrils Produces a whip-like movement of tail and propel sperm cell forward 77

78 Duct System After detaching from Sertoli cells, spermatozoa enter the rete testis Then flow through the efferent ducts to the epididymis Single, long, convoluted tube that connects the efferent ducts of the testis with the vas deferens Storage and maturation of spermatozoa Then flow into the vas deferens of the spermatic cord 78

79 Storage site for spermatozoa and a place for them to mature Flat ribbon-like structure that lies along the surface of the testis Head Body Tail The Epididymis 79

80 Vas Deferens Ductus deferens; part of the spermatic cord Passes through inguinal ring then separates from spermatic cord and connects with urethra Ampulla enlargement of the vas deferens just before it joins the urethra found in some species contain glands that contribute material to semen 80

81 Spermatic Cord Blood and lymphatic vessels, nerves, and the vas deferens. Pampiniform plexus meshwork of veins that surrounds testicular artery Maintains testes at a temperature slightly lower than body temperature Warms blood back to body temperature before it returns to the abdomen. 81

82 Spermatic Cord 82

83 The Vas Deferens moves the spermatozoa from the epididymis up to the urethra when ejaculation occurs spermatozoa mixed with secretions from accessory glands = semen 83

84 The Urethra 2 functions in the male Urinary Reproductive (ejaculation) Urine flow blocked during 2 portions in the male Pelvic portion Penile portion this function 84

85 Urethra Pelvic portion - entry point of vas deferens and accessory reproductive glands Penile portion - runs down the length of the penis Spermatozoa from vas deferens and secretions from accessory reproductive glands enter urethra and are pumped out as semen Carries urine from the urinary bladder outside the body. Urine flow temporarily blocked when ejaculation occurs 85

86 Accessory Reproductive Glands Ducts of glands enter pelvic portion of the urethra Different species have different combinations of glands 86

87 The Answer Key for the Previous Slide! 87

88 Comparative Anatomy Male Accessory Reproductive Glands Bassert Lab Manual 88

89 Accessory Reproductive Glands Produce alkaline fluid to help counteract acidity of female reproductive tract Electrolytes Fructose Prostaglandins Seminal vesicles Prostate gland Bulbourethral glands = Cowper s glands 89

90 Male breeding organ The Penis Composed of muscle, erectile tissue, connective tissue, a large blood supply, and many sensory nerve endings Urethra runs down center 3 main parts The roots The body The glans 90

91 The Penis The roots 2 bands of crura attach penis to brim of pelvis The body 2 bundles of erectile tissue Sinuses engorge with blood = erection ocorpus cavernosum urethrae = corpus spongiosum ocorpus cavernosum penis 91

92 The Penis The glans Distal end of penis with numerous sensory nerves Prepuce = sheath of skin that encloses the penis when it is not erect 92

93 Penis Comparative Anatomy CANINE EQUINE BOVINE 93

94 Canine Penis Urethra runs through groove on os penis Bulb of the glans remains swollen after ejaculation... the tie 94

95 Canine Penis Os Penis Bone 95

Equine Penis Contains large component of erectile tissue Glans flares into distinctive mushroom shape Corona glandis Urethral process extends from

96 Equine Penis Contains large component of erectile tissue Glans flares into distinctive mushroom shape Corona glandis Urethral process extends from central depression called the fossa glandis From Dyce KM, Sack WO, Wenseng CJG: Textbook of veterinary anatomy, ed 4, St Louis, 2010, Saunders. 96

97 Equine Penis 97

98 Equine Erection 98

99 Bovine Penis 99

100 Sigmoid Flexure Erection results from straightening the S shape of non-erect penis Penis protrudes from prepuce for breeding Retractor penis muscle pull penis back to non-erect, S shape 100

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102 Why Neuter? 102

103 Neutering by Species Species Intact Castrated Dog Dog Neutered Dog Cat Tom Neutered Tom Horse Stallion Gelding Cattle Bull Steer Pig Boar Barrow Sheep Ram Wether 103

104 Castration, neutering, OE Definition surgical removal of testicles Medical vs. behavioral reasons What age? Client education! Orchidectomy 104

105 McCurnin 8 th edition Page

106 Review Male Anatomy Trace a Sperm Cell 106

107 Male Dog Anatomy Review Answer Key 107

108 Quiz

109 Tom Cat Anatomy Review Answer Key 109

110 Quiz

The Reproductive System

PowerPoint Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College The Reproductive System 16PART A The Reproductive System Gonads primary sex organs Testes in males