Ch 27 The Reproductive System - PowerPoint Presentation

Ch 27 The Reproductive System& Related Issues

ASSIGNMENTMW Class: Please have this ppt filled in for MondayWF Class: Please have this ppt filled in for Wednesday

I. Reproductive System-Introduction Purpose Sexual Organs 1. Primary sex organs (gonads): testes and ovaries Functions: a) * Produce gametes = b) *Secrete Steroid Hormones: 2. Accessory reproductive organs: ducts, glands, and external genitalia

C. Human Life Cycle– Production of Gametes Homologous Chromosomes: Everyone has 23 pairs of Chromosomes, one from mom and one from dad; which is 46 total The Chromosomes of a pair are Homologous: Have same traits, but different genes for traits Diploid chromosomal number, 2n: 46 or 2 X 23 pairs Most body cells = diploid (2n) Haploid chromosomal number, 1n: Gametes are haploid because they have only one chromosome of each of the 23 pairs of homologous which is chromosomes= 23 total Fertilization restores the diploid number for offspring

C. Production of Gametes …5. Meiosis is the cell division that takes 1 diploid (2n) cell and divides it twice to form 4 haploid (1n) gametes each with one chromosomes, the mom one or the dad one, of each homologous chromosomes paira) Each egg randomly inherits only one chromosome of a pair, either the mom one or the dad one (or actually maternal grandmother or maternal grandfather to the potential offspring). There lots of different combinations. b) Each sperm also randomly inherits only one chromosome of a pair, either the mom one or the dad one (or actually paternal grandmother or paternal grandfather to the potential offspring). There are lots of different combinations. c) Offspring: Depending on which egg and which sperm unit to form the offspring, there are many, many different combinations possible for the offspring to inherit. See EXAMPLE NEXT SLIDE 

6 MOM (A = Grandma, B = Grandpa) DAD 1A 1B 2A 2B 3A 3B 4A 4B 5A 5B 1A 1B 2A 2B 3A 3B 4A 4B 5A 5B 6A 6B 7A 7B 8A 8B 9A 9B 10A 10B 11A 11B 12A 12B 6A 6B 7A 7B 8A 8B 9A 9B 10A 10B 11A 11B 12A 12B 13A 13B 14A 14B 15A 15B 16A 16B 17A 17B 18A 18B 13A 13B 14A 14B 15A 15B 16A 16B 17A 17B 18A 18B 19A 19B 20A 20B 21A 21B 22A 22B 23A 23B 19A 19B 20A 20B 21A 21B 22A 22B 23A 23B 1B 2B 3A 4B 5A 6A 7B 8B 9A 10A 11B 12B 13A 14B 15A 16A 17B 18B 19B 20A 21A 22B 23A = X 1A 2B 3B 4A 5B 6A 7A 8B 9B 10A 11B 12A 13A 14B 15B 16B 17A 18A 19A 20B 21A 22A 23B = Y EGG SPERM BABY

II. Anatomy of the Male Reproductive System A. Testes Seminal vesicle Prostate Bulbourethral gland Epididymis Testis Scrotum Ductus (vas) deferens Ejaculatory duct Urethra Outer Connective Tissue coverings Lobules : 250–300 per testes 3 . * Seminiferous Tubules : define Lobule

3. Seminiferous Tubules … 1-4 per Lobule *Function: Produce ? They end up i n fluid filled lumen spermatogenic cells within stratified epithelium that produce spermSustenacular (Serotoli) cells: are supporting cells that surround the developing sperm to protect them Interstitial Endocrine Cells (Cells of Leydig ): produce? Tunica vaginalis Tunica albuginea Spermatic cord Seminiferous Tubules Lobule Interstitial Endocrine Cells Spermatogenic Cells

Seminiferous Tubules … 4. Rete testis: sperm travel there from seminiferous tubules5. Descent of Testes: when? From where? 6. Sperm path : Seminiferous tubules → Rete Testis  Epididymis Scrotum 1. External genitalia = scrotum + penis2. *Scrotum:Function: has what within it?? *Two Muscles: Overall function? * Dartos Muscle : function? ii) * Cremaster Muscle : function? Rete testis Epididymis

Cremaster muscle Superficial fascia containing dartos muscle Skin Scrotum

C. The Penis = male copulatory organ1. Parts: root, shaft, head 2. * Erectile tissues: define copora cavernosa + corpus spogiosum*Function3. * Prepuce (foreskin ) : define D. The Male Duct System 1. Epididymis – functions: Stores sperm Gives nutrients to sperm * How long to mature?*During ejaculation: what does it do?Corpora cavernosa Corpus spongiosum Corpora cavernosa Prepuce (foreskin) Root of penis Shaft (body) of penis Crus of penis Head Epididymis Cross-Section Anterior View Ductus Deferens Epididymis

D . The Male Duct System Spongy urethra Ductus deferens Prostatic urethra Membranous urethra Ejaculatory duct Epididymis 2. Ductus Deferens: define * Function: Thick muscle layer does what? * Vasectomy: Spermatic Cord : to-and-from testes and through inguinal canal. Contains: Testicular Artery Venous Plexus Autonomic nerve Cremaster muscle Ductus Deferans 3. Ejaculatory duct – after seminal vesicle duct joins ductus deferens 4. * Urethra– Spongy , Membranous, & Prostatic: define Spermatic Cord

E . Accessory Glands *Seminal Vesicles: define - * Fluid pH: ? Why? - Nutrients given to sperm; Fructose- *% of semen: ?2.* Prostate – define Nutrient to sperm: Citrate Helps activate sperm * % of semen: ? Prostate-specific Antigen (PSA) Prostate Cancer Bulbourethral Gland and Duct: thick, clear mucusfor Lubrication & neutralizes urine Prostate Seminal vesicle

F. Semen Nutrients: Fructose & CitrateAlkalinity: pH=7.2-7.6 Vagina = pH3.5 - 4Antibiotic chemicals to kill some bacteria Suppress female immune responseE nhance sperm motility Amount per ejaculation = 2-5 ml Each ml has 20-150 M sperm

II. Physiology of the Male Reproductive Sys A. Male Sexual Response 1. Erection: Parasympathetic: via nitric oxide  arterioles & veins : dialate Expansion of corpora cavernosa Corpus spongiosum – urethra open 2. Ejaculation - sympathetic:Ducts/glands contract/empty contents in with sperm Bladder sphincter constricts : no urine in ejaculate Bulbospongiosus muscles: rapid contractions

Figure 27.7c Basal lamina Spermatogonium (stem cell) Cytoplasm of adjacent sustentacular cells Sustentacular cell nucleus Tight junction between sustentacular cells Lumen of seminifer- ous tubule Late spermatids Early spermatids Secondary spermatocytes Primary spermatocyte Spermatozoa Type B daughter cell Type A daughter cell remains at basal lamina as a stem cell (c) A portion of the seminiferous tublule wall, showing the spermato - genic cells surrounded by sustentacular cells (colored gold) B . Spermatogenesis in S eminiferous Tubule 1. Spermatogonium = stem cells at basal lamina of tubule Mitosis yields Type A and B daughter cells Type A = stem cell; 2. Meiosis forms four Spermatids from Type B cells 3. Four Sperm form when Spermatids physically change - B egins at puberty

Figure 27.7c Basal lamina Spermatogonium (stem cell) Cytoplasm of adjacent sustentacular cells Sustentacular cell nucleus Tight junction between sustentacular cells Lumen of seminifer- ous tubule Late spermatids Early spermatids Secondary spermatocytes Primary spermatocyte Spermatozoa Type B daughter cell Type A daughter cell remains at basal lamina as a stem cell (c) A portion of the seminiferous tublule wall, showing the spermato- genic cells surrounded by sustentacular cells (colored gold) B. Spermatogenesis … 4 . Sperm mature in e pididymis Production: 100 to 300 Million sperm produced per day b) Major Sperm parts i ) Head : genetic region w/ helmet-like acrosome = hydrolytic enzymes for egg penetration ii) Midpiece : metabolic region; mitochondria iii) Tail : locomotor region = flagellum

Figure 27.8a, b Centrioles Spermatid nucleus Golgi apparatus Acrosomal vesicle Mitochondria Approximately 24 days Excess cytoplasm Nucleus Acrosome Microtubules Flagellum Tail Head (a) (b) 1 2 3 4 5 6 7 Midpiece 4 . Sperm …

5. Role of Sustentacular (Sertoli) Cells Functions: a) Secrete testicular fluid with Androgen Binding Protein b) Protect sperm from immune system , 6. Interstitial (Leydig) CellsProduce androgens Sustentacular cell nucleus Tight junction between sustentacular cells Interstitial cells

C. Hormonal Regulation of Male Reprod. Function 1. HPG Axis– hypothalmus -pituitary-gonad Hypothalamus releases gonadotropin-releasing hormone (GnRH) which stimulates the Anterior P ituitary to secrete FSH and LH LH Interstitial cells release testosteroneFSH Sustentacular cells release androgen-binding protein (ABP) Testosterone then causes spermatogenesis & maturation of sex organs. W hen levels are high, it feeds back to inhibit the Hypo. & Pituitary Seminiferous tubule GnRH 1 Anterior pituitary Via portal blood LH FSH 2 2 Sustentacular cell 3 Testosterone Interstitial cells 4 Spermatogenic cells 5 6 7 Inhibin 8 Stimulates Inhibits

2. Effects of Testosterone During Puberty, Testosterone matures the male sex organs and then continues to maintains these organs along with male sex drive, and spermatogenesis Male Secondary Sex Characteristics – Non-reproductive affects by testosterone Appearance of pubic, axillary, chest, and facial hair Deepening of voice Skin thickens/becomes oilyBones grow and increase in densitySkeletal muscles increase in size and mass

Next ppt part-b

Review QuestionsThe ________ are the primary male sex organs and contain __________ ________ that actually manufacture sperm. seminiferous tubules testes

Review QuestionsGametes are generated through a cell division process called _________ which creates up to ___ haploid cells, each with _____ chromosomes in humans. 4 meiosis 23

Review Questions _____ stimulates the anterior pituitary to release ____ that stimulates sustenacular cells to release _____, and ___ that stimulates ____________________ cells to release testosterone. GnRH FSH ABP LH interstitial (Leydig)

Review QuestionsThe ____________ is the site of sperm maturation. The ________ _________ are responsible for secreting 70% of the volume of semen and their secretions include _________, a sugar to feed the sperm. epidydimus seminal vesicles fructose

Figure 27.5 (1 of 2) Mother cell (before chromosome replication) Chromosome replication Chromosome replication 2 n = 4 MITOSIS Replicated chromosome Prophase Chromosomes align at the metaphase plate Sister chromatids separate during anaphase 2 n 2 n Metaphase Daughter cells of mitosis Tetrad formed by synapsis of replicated homologous chromosomes Tetrads align at the metaphase plate Homologous chromosomes separate but sister chromatids remain together during anaphase I No further chromosomal replication; sister chromatids separate during anaphase II Daughter cells of meiosis II (usually gametes) n n n n Prophase I Metaphase I Daughter cells of meiosis I Meiosis II MEIOSIS Mitosis vs. Meiosis

Meiosis: Spermatocytes to Spermatids Basal lamina Spermatogonium (stem cell) Mitosis Growth Early spermatids Secondary spermatocytes Primary spermatocyte Late spermatids Spermatozoa Type B daughter cell Enters meiosis I Meiosis I completed Meiosis II Type A daughter cell remains at basal lamina as a stem cell (b) Events of spermatogenesis, showing the relative position of various spermatogenic cells

Figure 27.7c Basal lamina Spermatogonium (stem cell) Cytoplasm of adjacent sustentacular cells Sustentacular cell nucleus Tight junction between sustentacular cells Lumen of seminifer- ous tubule Late spermatids Early spermatids Secondary spermatocytes Primary spermatocyte Spermatozoa Type B daughter cell Type A daughter cell remains at basal lamina as a stem cell (c) A portion of the seminiferous tublule wall, showing the spermato- genic cells surrounded by sustentacular cells (colored gold) B . Spermatogenesis in seminiferous tubule 1. Spermatogonium = stem cells at basal lamina of tubule Mitosis yields Type A and B daughter cells Type A = stem cell; 2. Type B = primary spermatocyte These do Meiosis I to form 2 secondary spermatocyte that vary genetically All this begins at puberty

Figure 27.7c Basal lamina Spermatogonium (stem cell) Cytoplasm of adjacent sustentacular cells Sustentacular cell nucleus Tight junction between sustentacular cells Lumen of seminifer- ous tubule Late spermatids Early spermatids Secondary spermatocytes Primary spermatocyte Spermatozoa Type B daughter cell Type A daughter cell remains at basal lamina as a stem cell (c) A portion of the seminiferous tublule wall, showing the spermato- genic cells surrounded by sustentacular cells (colored gold) B. Spermatogenesis … 3. Secondary Spermatocytes undergo Meiosis II to each form 2 identical spermatids 4. Spermatids then physically change to become spermatozoon, sperm 5. Sperm mature in e pididymis 100 to 300 Million sperm produced per day

6. Role of Sustentacular (a.k.a. Sertoli) CellsSustentacular cell Functions, absorb excess cytoplasm from sperm, secrete testicular fluid with Androgen Binding Protein protect sperm from immune system , Blood-Testis Barrier-from tight junctions between Sustentacular cells and dividing spermatogonia: Prevents sperm antigens from activating the immune system 2. Basal compartment — spermatogonia and 1◦ spermatocytes Adluminal compartment — meioticaly active cells and lumen Sustentacular cell nucleus Tight junction between sustentacular cells

C. Hormonal Regulation of Male Reproductive Function 1. HPG Axis– hypothalmus-pituitary-gonad REVIEW Hypothalamus releases gonadotropin-releasing hormone (GnRH) GnRH stimulates anterior pituitary to secrete FSH and LH FSH  sustentacular cells release androgen-binding protein (ABP), concentrates testosterone near spermatogenic cellsLH interstitial cells release testosterone Seminiferous tubule GnRH 1 Anterior pituitary Via portal blood LH FSH 2 2 Sustentacular cell 3 Testosterone Interstitial cells 4 Spermatogenic cells 5 6 7 Inhibin 8 Stimulates Inhibits

C. Hormonal Regulation of Male reproductive Function … 1. HPG Axis … Testosterone  spermatogenesis (+ other somatic/psychological effects) Feedback inhibition on hypothalamus and pituitary due to: Rising levels of testosterone Inhibin (released when sperm count is high) Seminiferous tubule GnRH 1 Anterior pituitary Via portal blood LH FSH 2 2 Sustentacular cell 3 Testosterone Interstitial cells 4 Spermatogenic cells 5 6 7 Inhibin 8 Stimulates Inhibits

A. Testes … 2. Lobules: 250–300 per testes3. Seminiferous Tubules 1-4 per Lobule fluid filled lumen where sperm are Cells: spermatogenic cells within stratified epithelium w/Myoid cells: muscle outer layer Serotoli cells: are suporting cells called sustenacular cells that surround the developing sperm Tunica vaginalis Tunica albuginea Spermatic cord