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Physics Chemistry Organic Chemistry Biology
The Reproductive System
Scientific Figures
Click the link above to visit The Reproductive System in the Exploration Environment.
Click the thumbnails to reach 800 by 600 presentation slides.

The human male reproductive system

Human male reproductive system and adjacent structures

Penis, testis, urethra, prostate, bladder, rectum

Transverse section through the left side of the scrotum and the left testis.

Testicle of a cat: 1 Extremitas capitata, 2 Extremitas caudata, 3 Margo epididymalis, 4 Margo liber, 5 Mesorchium, 6 Epididymis, 7 testicular artery and vene, 8 Ductus deferens

1 Epididymis 2 Head of epididymis 3 Lobules of epididymis 4 Body of epididymis 5 Tail of epididymis 6 Duct of epididymis 7 Deferent duct (ductus deferens or vas deferens)

1 Head or upper pole of testis - 2 Tunica albuginea - 3 Testicular septa - 4 Anterior margin (free margin) - 5 Lateral surface - 6 Tail or lower pole of testis - 7 Testicular lobules - 8 Parenchyma of testis - 9 Efferent ductules - 10 Mediastinum testis - 11 Posterior margin

The right testis, exposed by laying open the tunica vaginalis.

microscopic picture of seminiferous tubule (cross section)

Transverse section through the left side of the scrotum and the left testis. (Semeniferous tubules visible in center, but not labeled.)

1: Testicular septa - 2: Convoluted seminiferous tubules - 3: Testicular lobules - 4: Straight seminiferous tubules - 5: Efferent ductules - 6: Rete testis

The deeper branches of the internal pudendal artery. (Bulbourethral gland labeled at center left.)

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

Vertical section of the testis, to show the arrangement of the ducts. (Labeled as vasa efferentia as top center.)

The spermatic cord in the inguinal canal.

Fundus of the bladder with the vesiculæ seminales.

Vertical section of bladder, penis, and urethra.

Prostate with seminal vesicles and seminal ducts, viewed from in front and above.

Cross-section of vas deferens through a microscope

Testis

Cross-section of seminiferous tubules. Arrows indicate location of Leydig cells.

Prostate

Prostate

Lobes of prostate

Zones of prostate

Prostate histology

Testosterone

Dehydroepiandrosterone

Androstenedione

Androsterone

Dihydrotestosterone

Dihydrotestosterone 3D

A sperm cell attempts to penetrate an ovum coat to fertilize it.

Diagram of a human spermatozoon

Cross section of the epithelium of a seminiferous tubule showing various stages of spermatocyte development

Germinal epithelium of the testicle. 1 basal lamina, 2 spermatogonia, 3 spermatocyte 1st order, 4 spermatocyte 2nd order, 5 spermatid, 6 mature spermatid, 7 Sertoli cell, 8 tight junction (blood testis barrier)

Histological section through testicular parenchyma of a boar. 1 Lumen of Tubulus seminiferus contortus, 2 spermatids, 3 spermatocytes, 4 spermatogonia, 5 Sertoli cell,

Schematic diagram of Spermatocytogenesis

Scheme showing analogies in the process of maturation of the ovum and the development of the spermatids (young spermatozoa).

Human spermatozoön

The human female's reproductive system.

The human female's reproductive system.

Schematic frontal view of female anatomy

Organs of the female reproductive system.

Schematic vulva anatomy.

Uterus and right broad ligament, seen from behind.

Sagittal section of the lower part of a female trunk, right segment.

Posterior half of uterus and upper part of vagina.

Vessels of the uterus and its appendages, rear view.

Median sagittal section of female pelvis.

Vertical section of mucous membrane of human uterus.

Histopathologic representation of endometrioid adenocarcinoma demonstrated in endometrial biopsy. Hematoxylin-eosin stain.

Section of the ovary. 1. Outer covering. 1’. Attached border. 2. Central stroma. 3. Peripheral stroma. 4. Bloodvessels. 5. Vesicular follicles in their earliest stage. 6, 7, 8. More advanced follicles. 9. An almost mature follicle. 9’. Follicle from which the ovum has escaped. 10. Corpus luteum.

Order of changes in ovary. - - 1 - Menstruation - 2 - Developing follicle - 3 - Mature follicle - 4 - Ovulation - 5 - Corpus luteum - 6 - Deterioration of corpus luteum

Diagram of folliculogenesis, starting from pre-antral (late secondary), courtesy NCBI

Histology of the preovulatory follicle

Section of vesicular ovarian follicle of cat. X 50.

Human ovarian follicle

Diagram showing the reduction in number of the chromosomes in the process of maturation of the ovum.

Corpus luteum

Early folliculogenesis from primordial to early tertiary.

First stages of segmentation of a mammalian ovum.

Steroidogenesis

Estrone

Androstendione converting to estrone

Estradiol

Estradiol - 3D

Conversion of testosterone to estradiol

Progesterone

Progesterone - 3D

Conversion of Pregnenolone to Progesterone

Progesterone is important for aldosterone (mineralocorticoid) synthesis, as 17-hydroxyprogesterone is for cortisol (glucocorticoid), and androstenedione for sex steroids.

Follicle Stimulating Hormone

The Activin dimer

Hormone levels during the menstrual cycle

HCG polypeptide structure

Menstrual cycle

An ovary about to release an egg.

In most mammalian fertilization, hyaluronidase is released by the acrosome of the sperm cell after it has reached the oocyte, by digesting proteins in the zona pellucida, thus enabling conception.

Acrosin is released from the acrosome of spermatozoa as a consequence of the acrosome reaction.

Acrosome reaction on a Sea Urchin cell

Human ovum. The zona pellucida is seen as a thick clear girdle surrounded by the cells of the corona radiata.

Blastocyst with an inner cell mass and trophoblast.

Section through ovum imbedded in the uterine decidua. Semidiagrammatic. - - am. Amniotic cavity. - b.c. Blood-clot. - b.s. Body-stalk. - ect. Embryonic ectoderm. - ent. Entoderm. - mes. Mesoderm. - m.v. Maternal vessels. - tr. Trophoblast. - u.e. Uterine epithelium. - u.g. Uterine glands. - y.s. Yolk-sac.

Primary chorionic villi. Diagrammatic.

Secondary chorionic villi. Diagrammatic

Blastodermic vesicle of Vespertilio murinus.

Section through embryonic disk of Vespertilio murinus.

Transverse section of a chorionic villus.

Scheme of placental circulation.

Placenta

Diagram showing earliest observed stage of human embryo.

Diagram illustrating early formation of allantois and differentiation of body-stalk.

Diagram showing later stage of allantoic development with commencing constriction of the yolk-sac.

iagram of a transverse section, showing the mode of formation of the amnion in the chick. The amniotic folds have nearly united in the middle line. Ectoderm, blue; mesoderm, red; entoderm and notochord, black. (Villi of chorion labeled at upper left.)

Surface view of embryo of Hylobates concolor.

Human embryo—length, 2 mm. Dorsal view, with the amnion laid open. X 30.

Model of human embryo 1.3 mm. long. (Villi of chorion labeled at lower right.)

Section through the embryo.

Human embryo of about fourteen days, with yolk-sac.

Human embryo of 2.6 mm.

Fetal circulation; the umbilical vein is the large, red vessel at the far left. The umbilical arteries are purple and wrap around the umbilical vein.

Human embryo from thirty-one to thirty-four days

The liver and the veins in connection with it, of a human embryo, twenty-four or twenty-five days old, as seen from the ventral surface. (Vitelline veins visible at center bottom.)

Diagram of the vascular channels in a human embryo of the second week. (After Eternod.) The red lines are the dorsal aortæ continued into the umbilical arteries. The red dotted lines are the ventral aortæ, and the blue dotted lines the vitelline veins.

Front view of two successive stages in the development of the digestive tube.

Sketches in profile of two stages in the development of the human digestive tube. (Vitelline duct labeled on bottom image.)

Sectional plan of the gravid uterus in the third and fourth month.

Anatomical model of a human pregnancy

Fetus in utero, between fifth and sixth months.

Opened uterus with cat fetus in midgestation: 1 umbilicus, 2 amnion, 3 allantois, 4 Yolk sac, 5 developing marginal hematoma, 6 maternal part of placenta (endometrium)

Fetus of about eight weeks, enclosed in the amnion. Magnified a little over two diameters.

Embryo at 4 weeks after fertilization

Fetus at 8 weeks after fertilization

Fetus at 18 weeks after fertilization

Fetus at 38 weeks after fertilization

Woman at the first month of pregnancy.

Relative size in 3rd Month (simplified illustration)

Relative size in 5th Month (simplified illustration)

Relative size in 9th Month (simplified illustration

7 weeks

13 weeks

17 weeks

20 weeks

The Lactating Breast. When the baby sucks, a hormone called oxytoxin starts the milk flowing from the alveoli, through the ducts (milk canals) into the sacs (milk pools) behind the areola and finally into the baby's mouth.

Cross section of the breast of a human female.

Dissection of a lactating breast. - 1 - Fat - 2 - Lactiferous duct/lobule - 3 - Lobule - 4 - Connective tissue - 5 - Sinus of lactiferous duct - 6 - Lactiferous duct


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