The Reproductive System 27 The Reproductive System

Urinary bladder Superficial inguinal ring (end of inguinal canal) Testicular artery Spermatic cord Ductus (vas) deferens Penis Autonomic nerve fibers Middle septum of scrotum Pampiniform venous plexus Cremaster muscle External spermatic fascia Epididymis Tunica vaginalis (from peritoneum) Superficial fascia containing dartos muscle Tunica albuginea of testis Scrotum Internal spermatic fascia Skin Figure 27.2

Online Bull reproductive tract dissection Figure 27.3a Section of a testicle of a steer, blood vessels injected with red gelatine. 1 parenchyma 2 mediastinum testis 3 tunica albuginea 4 tail of epididymis 5 head of epididymis 6 spermatic cord with convoluted testicular artery Bull testes: Schematic drawing of testicle and epididymis. 1 Tunica albuginea, 2 Septula testis, 3 Lobulus testis, 4 Mediastinum testis, 5 Tubuli seminiferi contorti, 6 Tubuli seminiferi recti, 7 Rete testis, 8 Ductuli efferentes testis, 9 Ductus epididymidis, 10 initial part of deferent duct Online Bull reproductive tract dissection

Seminiferous tubule (c) Interstitial cells Spermatogenic cells in tubule epithelium Areolar connective tissue Myoid cells Sperm Figure 27.3c

Cross section of seminiferous tubule Testes Each lobule contains one to four seminiferous tubules Tightly coiled structures Function as sperm-forming factories Empty sperm into the rete testis Sperm travels through the rete testis to the epididymis Interstitial cells produce androgens such as testosterone Cross section of seminiferous tubule Figure 16.1

Spermiogenesis (64-72 days) Lumen FSH + testosterone + testosterone Maturation sequence + LH (ICSH) Lumen

Sperm: Head (Acrosome + Nucleus), Midpiece (Mitochondria), Tail

Suspensory ligament of ovary Infundibulum Uterine tube Ovary Fimbriae Peritoneum Uterus Uterosacral ligament Round ligament Vesicouterine pouch Perimetrium Rectouterine pouch Urinary bladder Pubic symphysis Rectum Mons pubis Posterior fornix Cervix Urethra Anterior fornix Clitoris Vagina External urethral orifice Anus Hymen Urogenital diaphragm Labium minus Greater vestibular (Bartholin’s) gland Labium majus Figure 27.10

Uterine (fallopian) tube Uterine tube Ovarian blood vessels Fundus Suspensory ligament of ovary Uterine (fallopian) tube Uterine tube Ovarian blood vessels Fundus of uterus Lumen (cavity) of uterus Ampulla Mesosalpinx Ovary Isthmus Mesovarium Infundibulum Broad ligament Fimbriae Mesometrium Round ligament of uterus Ovarian ligament Endometrium Body of uterus Myometrium Wall of uterus Ureter Uterine blood vessels Perimetrium Isthmus Internal os Uterosacral ligament Cervical canal Lateral cervical (cardinal) ligament External os Vagina Lateral fornix Cervix (a) Figure 27.12a

4. 3. 1. 2. 5. 6. 8. 7. Tunica albuginea Oocyte Granulosa cells Late secondary follicle 4. Degenerating corpus luteum (corpus albicans) Cortex 3. Mesovarium and blood vessels 1. 2. Germinal epithelium Vesicular (Graafian) follicle Primary follicles Antrum Oocyte 5. Ovarian ligament Zona pellucida 6. Theca folliculi Medulla 8. 7. Ovulated oocyte Corpus luteum Developing corpus luteum Corona radiata (a) Diagrammatic view of an ovary sectioned to reveal the follicles in its interior Figure 27.11a

Ovarian Tissue Corpora lutea

Oogenesis General Features Steps of Oogenesis The total supply of eggs are present at birth Ability to release eggs begins at puberty Reproductive ability ends at menopause Steps of Oogenesis Oocytes are matured in developing ovarian follicles Oogonia – female stem cells found in developing fetus, divide mitotically-> 1o oocytes Primary oocytes are surrounded by cells that form primary follicles in the ovary Oogonia no longer exist by the time of birth Primary oocytes are inactive until puberty Follicle stimulating hormone (FSH) causes some primary follicles to mature Meiosis starts inside maturing follicle producing a secondary oocyte and the first polar body Meiosis is completed after ovulation only if sperm penetrates and two additional polar bodies are produced

Mons pubis Labia Prepuce majora of clitoris Labia minora Clitoris (glans) Urethral orifice Vestibule Hymen (ruptured) Vaginal orifice Anus Opening of the duct of the greater vestibular gland (a) Figure 27.14a

Pectoralis major muscle Suspensory ligament First rib Skin (cut) Pectoralis major muscle Suspensory ligament Adipose tissue Lobe Areola Nipple Opening of lactiferous duct Lactiferous sinus Lactiferous duct Lobule containing alveoli Hypodermis (superficial fascia) Intercostal muscles (a) (b) Figure 27.15

Uterine (Menstrual) Cycle Cyclic changes in endometrium in response to ovarian hormones Three phases Days 1–5: menstrual phase Days 6–14: proliferative (preovulatory) phase Days 15–28: secretory (postovulatory) phase (constant 14-day length)

Endometrium of the Uterus Lumen of uterus Epithelium Capillaries Uterine glands Venous sinusoids Lamina propria of connective tissue Spiral (coiled) artery Straight artery Endometrial vein Smooth muscle fibers Radial artery Arcuate artery Uterine artery (b) Figure 27.13b

Uterine Cycle Menstrual phase Endometrial glands Blood vessels Menstrual flow Functional layer Basal layer Days Menstrual phase Proliferative phase Secretory phase Menstrual phase Ovarian hormones are at their lowest levels Gonadotropins are beginning to rise Stratum functionalis of the endometrium is shed and the menstrual flow occurs

Uterine Cycle Proliferative phase Endometrial glands Blood vessels Menstrual flow Functional layer Basal layer Days Menstrual phase Proliferative phase Secretory phase Proliferative phase Estrogen levels prompt generation of new functional layer and increased synthesis of progesterone receptors in endometrium Glands enlarge and spiral arteries increase in number Rebuilding of the functional layer of the endometrium (stratum functionalis). Perimetrium

Uterine Cycle Endometrial glands Blood vessels Menstrual flow Functional layer Basal layer Days Menstrual phase Proliferative phase Secretory phase Secretory phase Begins immediately after ovulation. Progesterone levels prompt Further development of endometrium Glandular secretion of glycogen Formation of the cervical mucus plug Enrichment of the blood supply and glandular secretion of nutrients prepare the endometrium to receive an embryo Perimetrium

Sheep vs Human Uteri Cow uterus dissection online

Mammary Glands