Chapter 26: Reproductive Systems BIO 218 Fall 2015 Male Male reproductive system is composed of... Gonads (testes) Duct system (epididymis, ductus deferens, ejaculatory ducts, urethra) Accessory sex glands (seminal vesicles, prostate, cowper s glands) Supporting structures (scrotum, penis) 1
Male gonads = Testes (aka testicles) Tunica vaginalis Tunica albuginea Septa Lobules Seminiferous tubules Fig. 26.3a Testis Seminiferous Tubules Testis Wall of Seminiferous Tubule 2
Sertoli(sustentacular) cells Fig. 26.4a Sertoli Cells Support and protection of developing germ cells Nourish developing germ cells Spermiogenesis Spermiation Produce fluid for sperm transport Secrete the hormone inhibin Form blood-testis barrier Sertoli cells & blood-testis barrier Fig. 26.4b 3
Spermatocytogenesis Spermatogenesis Meiosis Spermiogenesis Spermiation Spermatocytogenesis & Meiosis Spermatogonia Spermatocytes Spermatids Fig. 26.5 Spermiogenesis 4
Spermiation Sperm cells are released from Sertoli cells into the lumen of the seminiferous tubules Cells are not motile, fluid secreted by Sertoli cells aids in their transport Fig. 26.5 Spermatozoa 300 x 10 6 per day Fig. 26.6 Leydig Cells http://www.colorado.edu/intphys/class/iphy3430-200/image/figure20f.jpg 5
Scrotum 28_02 Descent of the Testes 6
Visceral Layer of Tunica Vaginalis Parietal Layer of Tunica Vaginalis Hydrocele 7
Seminiferous Tubules Straight Tubule Rete Testis 8
Efferent Ductules Epididymis Epididymis Lined with PCET & smooth muscle Microvilliincrease the surface area for the reabsorption of degenerated sperm During sexual arousal, peristaltic waves aid in sperm transport towards the ductus deferens Sperm maturation occurs here (acquire motility & the ability to fertilize female gametes) Sperm storage 9
28_09a Fig. 26.9 60% of ejaculate Components of fluid Seminal Vesicles Alkaline, viscous fluid Fructose Prostaglandins Clotting proteins 28_09a Fig. 26.9 10
25% of ejaculate Components of fluid Prostate gland Citric acid Proteolytic enzymes (PSA, pepsinogen, etc.) Acid phosphatase (?) Seminalplasmin 28_09a Fig. 26.9 11
Bulbourethral(Cowper s) gland Components of fluid Alkaline fluid Mucus (lubricates the end of the penis and the lining of the urethra, decreasing injury during ejaculation) 28_09a Fig. 26.9 Penis Passageway for semen and the excretion of urine Body (erectile tissue) Root (bulb & crura) Glans Fig. 26.10a 12
Erectile Tissue Fig. 26.10c Erection NO from the PNS causes smooth muscle in the walls of the arterioles to relax NO also causes smooth muscle in erectile tissue to relax (widening of blood sinuses) Blood enters erectile tissue Expansion of the blood sinuses compresses veins draining the penis Ejaculation Spinal reflex (sacral) Smooth muscle sphincter at base of urinary bladder closes Peristaltic contractions of epididymis, ductus deferens, seminal vesicles, ejaculatory ducts, and prostate propel semen into the penile urethra 13
Female 28_12 Fig. 26.12a Ovaries Germinal epithelium, tunica albuginea, cortex, medulla, ovarian follicles Fig. 26.13 14
Oogenesis & Follicular Development Oogenesis begins prior to birth Primordial germ cells migrate to the ovaries PGCs differentiate into oogoniawhich proliferate by mitosis Most oogonia will degenerate (atresia) Some oogonia will develop into primary oocytes (arrest in Prophase I) Primary oocytesare surrounded by a single layer of follicular cells Primordial Follicle Primary oocyte + follicular cells Development does not continue until puberty At birth 2 million At puberty 40,000 Ovulated - 400 Fig. 26.14a Primary Follicle Primary oocyte surrounded by several layers of granulosa cells Zona pellucida Theca folliculi Fig. 26.14b 15
Secondary Follicle Primary oocyte Granulosa cells secrete follicular fluid which is found in the antrum Corona radiata Theca folliculi becomes theca interna and theca externa Fig. 26.14c Graafian Follicle Large follicle Large antrum Primary oocyte resumes meiosis Fig. 26.14d 28_15 16
Ovulation of Secondary Oocyte 28_table_01 Table 26.1 28_23 17
Uterine Tubes aka Fallopian tubes aka Oviducts Fig. 26.16a 28_17b Fig. 26.17c Oviducts Mucosa Ciliated simple columnar epithelium Cilia help move oocyte or ovum towards the uterus Peg cells provide nutrition Muscularis peristaltic contractions aid in movement of oocyte (ovum) towards uterus Serosa 18
Tubal Ligation Uterus Fig. 26.16a Uterus - functions Pathway for sperm to reach the oviducts Site of implantation of the pre-embryo Site of embryonic & fetal development Part of birth canal 19
Uterine Walls Perimetrium Myometrium Endometrium Fig. 26.18 Stratum basalis Stratum functionalis Endometrium Fig. 26.18b 28_19 Uterine arteries Arcuate arteries Radial arteries Straight and spiral arterioles Uterine veins Internal iliac veins 20
Cervix mucus production Vagina Vagina functions Female copulatory organ Outlet for menstrual flow Part of birth canal 21
Vulva (pudendum) includes... Mons pubis Labia majora (labium majus) Labia minora (labium minus) Clitoris Vestibule Hymen Vaginal orifice EUO Ducts Fig. 26.21 Perineum Fig. 26.22 28_22 Fig. 26.23 22
Female Reproductive Cycle 28_24a Fig. 26.25 23