Reproductive System

1
Reproductive System

• Introduction
• Overview of the Reproductive System
• Male Reproductive System
• Female Reproductive System
• Physiology of Sexual Intercourse

2
Introduction

• Meiotic Cell Division
• Sex Determination
• Functions of the Reproductive System
• Reproductive System Overview
• Male
• Female

3
Learning Objectives

• Meiosis
• Outline the major stages phases of meiotic cell
  division
• Sex Determination
• Explain how sex is determined genetically
  describe the consequences of the Sry gene
• Introduction
• Summarize the functions of the human reproductive
  system and its principle components

4
Meiotic Cell Division

• Interphase preparatory stage
• Meiosis I 1st nuclear division halving of the
  chromosome number
• 1st Cytokinesis division of the cytoplasm 2
  daughter cells formed

5
Meiotic Cell Division

• (Interkinesis) in some kinds of
  organisms
• Meiosis II 2nd nuclear division in both cells
  from meiosis I separation of the sister
  chromatids
• 2nd Cytokinesis division of the cytoplasm in
  both cells from meiosis I 4 daughter cells
  formed

6
Interphase

• G1 Phase
• cell grows larger organelles duplicated
• S Phase
• synthesis of DNA replication of chromosomes to
  form sister chromatids
• G2 Phase
• cell growth continues necessary materials for
  division are synthesized

7
Meiosis I Reduction Division

• Prophase I (includes Prometaphase)
• similar to mitosis except homologous chromosomes
  pair in synapsis to form tetrads
• Metaphase I
• similar to mitosis except homologs line up
  across the metaphase plate
• Anaphase I
• similar to mitosis except homologs are separated
  to opposite poles of the cell
• Telophase I
• similar to mitosis except nuclei may or may not
  reform completely

8
1st Cytokinesis

• Begins w/ telophase I ends after telophase I
• Results in 2 daughter cells
• Daughter cells contain ½ of original chromosomes
• haploid cells

9
Interkinesis

• Occurs in some species
• after telophase I 1st cytokinesis
• Nuclei of daughter cells completely reform
• Chromosomes still as joined as sister chromatids
  decondense
• G phases may occur NO S phase

10
Meiosis IIEquational Division

• Prophase II (includes Prometaphase)
• Metaphase II
• Anaphase II
• Telophase II
• same processes as mitosis for all phases

11
2nd Cytokinesis

• Begins w/ telophase II ends after telophase II
• Results in 4 daughter cells
• Daughter cells contain ½ of original chromosomes
• haploid cells
• 1 or more will form gametes

12
Review ofMeiotic Cell Division
13
Human Karyotype
2 sets Chromosomes diploid 46
1 set Chromosomes haploid 23
Note 23 pairs of chromosomes 2 sets
14
Sex Determination

• Autosomes
• Chromosomes that carry most of the structural
  genes NO sex characteristics
• 22 pairs
• Sex Chromosomes
• Chromosomes that carry sex genes determine sex
  in combination
• 1 pair

15
Sex Chromosomes

• Genetic characteristics
• X female characteristics
• X chromosome carries basic sex characteristic
  genes some structural genes
• Y male characteristics
• Y chromosome carries SRY gene that produces
  testosterone almost NO other genes
• Sex Determination
• XX female
• XY male

16
Comparison Male Female Development
2 Months
3 Months
4 Months
7 Months
Birth
17
Functions of the Reproductive System

• Perpetuation of the species
• Maintenance of secondary sex characteristics
• Promotion of pair bonding

18
Overview of the Reproductive System

• Gonads
• Reproductive organs that produce reproductive
  cells hormones
• Male testes
• gametes sperm
• hormones testosterone inhibin
• Female ovaries
• gametes ova
• hormones estrogens progesterone

19
Animal Life Cycle
20
Overview of the Male Reproductive System

• Duct System
• Epididymus
• Ductus (vas) deferens
• Ejaculatory duct
• Urethra
• Function
• Deliver sperm supporting secretions into the
  female reproductive system

21
Overview of the Male Reproductive System

• Accessory Organs Glands
• Seminal vesicles
• Prostate gland
• Bulbourethral glands
• General Functions
• Provide nourishment protection for spermatozoa
  (sperm)

22
Overview of the Female Reproductive System

• Duct System
• Uterine tubes (oviducts/fallopian tubes)
• Uterus
• Vagina
• Functions
• Deliver ovum or embryo to the uterus
• Provide environment for development of an
  embryo/fetus
• Serve as the birth canal
• Serve as an exit for menstrual fluids

23
Overview of the Female Reproductive System

• Accessory Organs Glands
• Vestibular glands
• Mammary glands
• Functions
• Produce lubricating fluids to aide coitus
• Provide nourishment for offspring

24
Male Reproductive System

• Testes
• Spermatogenesis
• Spermiogenesis
• Accessory ducts
• Accessory glands
• Semen composition function
• External genitalia
• Hormonal controls

25
Learning Objectives

• Male Reproductive System
• Describe internal external components of the
  male reproductive system
• Describe the roles of the accessory ducts
  glands
• Spermatogenesis Spermiogenesis
• Outline the stages of sperm development
  maturation

26
Learning Objectives

• Semen Composition
• Discuss the composition of semen describe the
  function of the various glandular secretions
• Hormonal Control
• List the hormones associated w/ male reproductive
  physiology describe the role of each

27
Testes

• Testicular lobules
• Seminiferous tubules
• Produce gametes sperm
• Produce hormones testosterone inhibin
• Straight tubules
• Carry sperm from seminiferous tubules
• Rete testis
• Carry sperm to efferent ducts
• Efferent ducts
• Carry sperm to epididymus

28
Spermatogenesis
Diploid
Haploid
29
Spermiogenesis
30
Special Cells

• Sustentacular (Sertoli) cells
• Locus w/in seminiferous tubules
• Function nourish developing sperm
• stimulate spermatogenesis spermiogenesis
  secrete inhibin
• Interstitial (Leydig) cells
• Locus spaces btw seminiferous tubules
• Function stimulate activity of sustentacular
  cells secrete testosterone

31
Accessory Ducts

• Epididymus
• sperm maturation storage
• Ductus (vas) deferens
• sperm duct from epididymus to seminal vesicles
• Ejaculatory duct
• sperm duct from seminal vesicle to urethra
• Urethra prostatic/membranous/penile
• sperm duct into female

32
Male Reproductive System
33
External Genitalia

• Penis
• intromittent organ for delivery of sperm into
  female reproductive tract
• Scrotum
• pouch containing testes maintains sperm
  development at 35.9 oC (96.6 oF)

34
Penis

• Root crura connective tissue attached to pubic
  bone
• Shaft body of penis
• Erectile tissues
• Corpora cavernosa
• Corpora spongiosum
• Glans head of penis
• Prepuce (foreskin) cover often circumcised
• Stimulation function
• Urethral meatus opening

35
Penis
36
Accessory Glands

• Seminal vesicles
• Contribute to semen
• Prostate gland
• Contribute to semen
• Bulbourethral glands
• Preejaculatory fluid

37
Semen Composition

• Ejaculate volume
• 2 5 mL
• Analysis
• Spermatozoa 1
• Count 60 million
• Motility 60 beating flagella
• Morphology 60 normal shape

38
Semen Composition

• Analysis (cont)
• Seminal fluid
• From seminal vesicles 60
• From prostate gland 30
• From sustenacular cells of seminal tubules
  small glands in epididymus 5
• From bulbourethral glands 4

39
Seminal Fluid Function

• Seminal vesicle secretion
• Fructose nourished spermatozoa
• Prostaglandins stimulate contractions along
  male female reproductive tracts
• Fibrinogen forms temporary clot in vagina
• Alkaline fluid neutralize prostatic fluid
  vaginal acidity

40
Seminal Fluid Function

• Prostatic fluid
• Seminalplasmin antibiotic
• Slightly acidic fluid
• Bulbourethral gland secretion
• Alkaline mucus preejaculatory neutralizes
  acidity of urethra
• Lubricates glans

41
Male Reproductive Hormones

• GnRH (gonadotropin releasing hormone)
• Released by hypothalamus of brain
• Target tissue anterior pituitary
• Function/effect stimulate release of
  gonadotropic hormones FSH LH
• FSH (follicle stimulating hormone)
• Released by anterior pituitary
• Target tissue testes sustenacular cells
• Function/effect stimulation of spermatogenesis
  spermiogenesis
• release of inhibin

42
Male Reproductive Hormones

• LH (leutinizing hormone)
• Released by anterior pituitary
• Target tissue testes interstitial cells of
  testes
• Function/effect stimulate production of
  testosterone
• Inhibin
• Released by sustentacular cells of seminiferous
  tubules
• Target tissue anterior pituitary
• Function/effect feedback inhibition of FSH

43
Male Reproductive Hormones

• Testosterone
• Released by interstitial cells of testes
• Target tissue various
• Function/effect
• Stimulation of spermatogenesis spermiogenesis
• Maintenance of accessory glands organs
• Establishment maintenance of secondary sex
  characteristics
• Stimulation of bone muscle growth
• Effects on CNS libido aggression (?)

44
Female Reproductive System

• Ovaries
• Oogenesis
• Accessory ducts organs
• Accessory glands
• External genitalia
• Hormonal controls

45
Learning Objectives

• Female Reproductive System
• Describe internal external components of the
  female reproductive system
• Describe the roles of the accessory ducts,
  organs, glands
• Oogenesis
• Outline the stages of ova development maturation

46
Learning Objectives

• Ovarian Cycle
• Discuss the development of follicles in the
  ovary, ovulation, formation of the corpus
  luteum relate each stage to hormonal influences
• Uterine Cycle
• Discuss the changes in the endometrium of the
  uterus relative to the ovarian cycle and
  menstruation

47
Learning Objectives

• Mammary Glands
• Describe the structures associated with female
  mammary gland function
• Hormonal Control
• List the hormones associated w/ female
  reproductive physiology describe the role of
  each

48
Ovaries

• Follicles
• Primordial follicles
• Present at birth 2million oocytes arrested at
  meiosis I prophase 300,000 remain by age 7
• Primary oocyte (2n) 1 layer follicular cells
• Primary follicles
• Form after sexual maturity
• Primary oocyte layers of follicular cells
  granulosa cells

49
Ovaries

• Follicles (cont)
• Secondary follicles
• Primary oocytes granulosa cells
• Follicular fluid forms in follicle
• Tertiary (Graafian) follicles
• Meiosis I completes ? secondary oocyte (n)
• Oocyte in antrum
• Follicle bulges from ovarian surface
• Note 400-500 ova will reach this stage from
  puberty to menopause

50
Oogenesis
Diploid
Haploid
51
Accessory Organs Ducts

• Uterine tubes (oviducts fallopian tubes) site
  of fertilization
• Fimbriae infundibulum entrance to uterine
  tube captures ovulated ovum
• Ampulla (bend) isthmus (entry to uterus)
  fertilization occurs in this region
• Uterus nurturing environment for fetus
• Cervix mucus plug prevents uterine infection

52
Accessory Organs Ducts

• Vagina
• Receptacle for male organ holds spermatozoa
• Elimination of menstrual fluids
• Lower birth canal

Rugae
53
Female Reproductive System
Mons pubis
54
External Genitalia

• Female accessory external organs (cont)
• Vulva external genitalia
• Labia minora majora protect vaginal opening
• Clitoris stimulation

55
Accessory Glands

• Female accessory glands (cont)
• Lesser vestibular glands lubrication
• Greater vestibular (Bartholins) glands
  lubrication
• Vaginal mucus glands protection lubrication

56
Female Reproductive Hormones

• GnRH (gonadotropin releasing hormone)
• Released by hypothalamus of brain
• Target tissue anterior pituitary
• Function/effect stimulate release of
  gonadotropic hormones FSH LH
• FSH (follicle stimulating hormone)
• Released by anterior pituitary
• Target tissue ovaries follicular cells
• Function/effect stimulation of follicle
  development
• release of inhibin

57
Female Reproductive Hormones

• LH (leutinizing hormone)
• Released by anterior pituitary
• Target tissue ovaries tertiary follicle
• Function/effect stimulates ovulation
• stimulates progesterone production by corpus
  luteum
• Inhibin
• Released by granulosa cells (tertiary follicle)
• Target tissue anterior pituitary
• Function/effect feedback inhibition of FSH

58
Female Reproductive Hormones

• Estrogens
• Released by granulosa cells (developing
  follicles)
• Target tissue uterus various
• Types of estrogen
• Estradiol most common dominant prior to
  ovulation
• Estrone
• Estriol

59
Steroid HormoneSynthesis
60
Female Reproductive Hormones

• Estrogens (cont)
• Function/effect
• Stimulation of LH spike - after day 10
• Increase pulse frequency of GnRH
• Stimulation of corpus luteum development
  progesterone secretion by corpus luteum day 14
  (ovulation) to day 18
• Initiating repair growth of endometrium day
  7-28
• Maintenance of accessory glands organs
• Establishment maintenance of secondary sex
  characteristics
• Stimulation of bone muscle growth
• Effects on CNS libido

61
Female Reproductive Hormones

• Progesterone
• Released by corpus luteum
• Target tissue uterus
• Function/effect
• Maintenance of uterine endometrium for pregnancy
• Decreased pulse frequency of GnRH to lower FSH
  LH levels

62
The Ovarian Cycle

• Follicular Phase
• Preovulatory phase
• Follicle maturation
• Day 1-10
• Ovulatory Phase
• Follicle rupture release of ovum from ovary
• Day 11-14
• Luteal Phase
• Postovulatory phase
• Formation of corpus luteum
• Day 15-28

63
Follicular Phase

• Step 1 Formation of primary follicles
• Primordial follicles FSH? primary follicles
• 1o oocyte (2n) surrounded by layers of granulosa
  cells
• Zona pellucida microvilli interface
• Many primordial follicles enter this phase
• Step 2 Formation of secondary follicles
• Follicular fluid separates inner granulosa layer
  1o oocyte from outer granulosa cells
• Only a few primary follicles enter this phase

64
Primary Follicles
1o oocyte
Oocyte nucleus
Granulosa cells
65
Secondary Follicle
1o oocyte
Follicular fluid
Granulosa cells
66
Follicular Phase

• Step 3 Formation of a tertiary (Graafian)
  follicle
• 1o oocyte (2n) --LH? 2o oocyte (n) polar body
• Note oocyte has been in prophase I since before
  birth
• Antrum central chamber
• 2o oocyte ring of granulosa cells now zona
  radiata drift into antrum
• Only one secondary follicle becomes a tertiary
  follicle

67
Tertiary Follicle
Antrum w/ follicular fluid
2o oocyte
Corona radiata
Granulosa cells
68
Ovulatory Phase

• Step 4 Ovulation
• 2o oocyte (n) --LH? bursts from (vesicular)
  follicle into pelvic cavity
• 2o oocyte surrounded by corona radiata held to
  oocyte by zona pellucida
• 2o oocyte swept by fimbriae-generated currents
  into infundibulum uterine tube

69
Tertiary Follicle
Ovulation
70
Luteal Phase

• Step 5 Formation of the corpus luteum
• Tertiary follicle collapses
• LH influences remaining granulosa cells form
  endocrine gland corpus luteum
• Corpus luteun secretes
• Lg amnts of progesterone
• Sm amnts of estrogens

71
Luteal Phase

• Step 6 Degeneration of the corpus luteum
• Without fertilization of ovum resulting
  pregnancy
• Corpus luteun degenerates to corpus albicans 12
  days after ovulation
• Cessation of estrogen progesterone production

72
Ovarian Follicles
73
The Uterine Cycle(Menstrual Cycle)

• Menses (Phase)
• Degeneration of the functional zone of
  endometrium
• Caused by reduced blood flow in absence of
  progesterone
• Menstruation blood tissues slough into
  uterine cavity exit via cervical os vagina
• Day 1-5 (follicular phase of ovarian cycle)

74
Uterine Wall
75
Menses
Myometrium
Functional zone
Basilar zone
Endometrial glands
76
The Uterine Cycle(Menstrual Cycle)

• Proliferative Phase
• Growth vascularization of the functional zone
  of the endometrium
• Endometrial gland formation
• Caused by increased blood flow nutrient input
  due to increasing levels of estrogen from
  developing follicles
• Day 6-13 (follicular phase of ovarian cycle)

77
Proliferative Phase
Basilar zone
Myometrium
Functional zone
Endometrial glands
78
The Uterine Cycle(Menstrual Cycle)

• Secretory Phase
• Enriched blood nutrient flow to the functional
  zone of the endometrium
• Endometrial gland enlargement
• Caused by increasing levels of progesterone (
  moderate estrogen) from the corpus luteum
• Day 14-28 (ovulation through luteal phase of
  ovarian cycle)

79
Secretory Phase
Endometrial glands
80
Uterine Cycle
81
Terminology

• Menarche
• First menstruation
• At puberty age 10-12
• Amenorrhea
• Primary failure to initiate menses
  developmental/genetic abnormalities
• Secondary - transient or temporary failure of
  menses emotional or physical stress

82
Terminology

• Menopause
• Last menstruation
• Results from lack of ova able to enter the
  ovarian cycle
• Estrogen progesterone loss due to termination
  of ovarian cycle
• Late middle-age age 45-55

83
Mammary Glands Tissues

• Structure
• Lobular arrangement
• Mammary glands ? lactiferous ducts ? lactiferous
  sinuses ? nipple
• Separate openings in nipple at center of areole
• Supported by suspensory ligaments
• Underlying pectoral fat pad atop pectoralis
  muscle integumentary origin
• Lactation
• Stimulated by prolactin from anterior pituitary
  at end of pregnancy

84
Mammary Glands
85
Hormonal RegulationOvarian Cycle
86
ComparisonOvarian, Uterine, Hormonal Cycles