Anatomy and Histology of the Male and Female Reproductive Systems, Lab Reports of Physiology

Download Anatomy and Histology of the Male and Female Reproductive Systems and more Lab Reports Physiology in PDF only on Docsity! Lab Activity 33 Anatomy of the Reproductive System Portland Community College BI 233 2 Scrotum • Sac of skin and superficial fascia that hangs outside the abdominopelvic cavity at the root of the penis • Contains paired testicles separated by a midline septum • Its external positioning keeps the testes 3°C lower than core body temperature Seminal VESiCle ggg urinary bladder Prostate gland Prostatic urethra Urogenital! diaphragm - aS : Bulbourethral Glans External urethral orifice 6 Penis Histology 7 Testicles • Seminiferous tubules: • Produce the sperm • Converge to form the tubulus rectus • The straight tubulus rectus conveys sperm to the rete testis • From the rete testis, the sperm: • Leave the testis via efferent ductules • Enter the epididymis • Surrounding the seminiferous tubules are interstitial cells 10 Seminiferous Tubules “Sperm Factory” • Sertoli Cells (sustentacular cells) • Support and nourish the spermatogenic cells • Completely surround the spermatic cells undergoing meiosis • Creates the blood-testes barrier • Stimulated by FSH • Secretes: • Androgen binding protein (ABP): Concentrates testosterone in the seminiferous tubules • Inhibin: Released when sperm production is too high (slows it down). Inhibits the secretion of FSH and GnRH Seminiferaus tubule Epidichy ris Immature sperm Seminiferous Tubules Leydig cell 12 15 Ductus Deferens and Ejaculatory Duct • Ductus Deferens: Runs from the epididymis through the inguinal canal into the pelvic cavity • Ampulla: The expanded terminal end on posterior bladder • Ejaculatory Duct: Formed from the ampulla and the duct of the seminal vesicle • Most of it is in the prostate gland • Propels sperm from the epididymis to the urethra Ampulla Seminal vesicle i J Ss oo 16 17 Spermatic Cord • Contains the structures running from the testicles to the pelvic cavity. • Passes through the inguinal canal • Contents: • Vas Deferens • Nerves • Blood Vessels 20 Accessory Glands: Prostate Gland • Doughnut-shaped gland that encircles part of the urethra inferior to the bladder • Plays a role in the activation of sperm • Enters the prostatic urethra during ejaculation • Prostatic secretions include: • Citrate: is a food source (TCA cycle) • Proteolytic enzymes: acts to "decoagulate" the semen that was coagulated by seminal vesicle secretions, which helps the sperm begin their journey once inside the vagina 21 Bulbourethral Glands (Cowper’s Glands) • Pea-sized glands inferior to the prostate • Produce alkaline mucus prior to ejaculation that neutralizes traces of acidic urine in the urethra 22 Sperm Summary • Produced: Seminiferous tubules • Stored: Epididymis • Transported through epididymis by rhythmic peristaltic contractions as they mature • Epididymis
Vas Deferens
Ejaculatory duct (ampulla of vas deferens fuses with duct of seminal vesicle “ejaculatory duct”)
prostate
prostatic urethra (then passes the bulbourethral gland)
membranous urethra
penile urethra 25 Vagina • Thin-walled tube lying between the bladder and the rectum, extending from the cervix to the exterior of the body • Wall consists of three coats: fibroelastic adventitia, smooth muscle muscularis, and a stratified squamous mucosa • Mucosa near the vaginal orifice forms an incomplete partition called the hymen • Vaginal fornix: upper end of the vagina surrounding the cervix 26 Bartholin’s Glands (aka: Vestibular Glands) • The Bartholin's glands are located on each side of the vaginal opening. • They secrete fluid that helps lubricate the vagina. • Sometimes the ducts of these glands become obstructed. • Fluid backs up into the gland and causes swelling (Bartholin's cyst) Female: Lateral View Uterine tube Broad ligament Myometrium Vesicouterine pouch Perimetrium | Uterus Endometrium Pubic symphysis Urethra Paraurethral glands Clitoris “ Labium minus Labium majus 30 Uterine Tubes (Fallopian Tubes) • Receive the ovulated oocyte and provide a site for fertilization • Empty into the superolateral region of the uterus via the isthmus • Expand distally around the ovary forming the ampulla • The ampulla ends in the funnel-shaped, ciliated infundibulum containing fingerlike projections called fimbriae 31 Uterine Tubes (Fallopian Tubes) • Function: events occurring in the uterine tube • Fimbriae sweep oocyte into tube, cilia & peristalsis move it along, sperm reaches oocyte in ampulla, fertilization occurs within 24 hours after ovulation & zygote reaches uterus about 7 days after ovulation 32 Fallopian Tube Histology Cilia sweep egg/zygote toward the uterus 35 Uterine Histology • Endometrium • Simple columnar epithelium • Stroma of connective tissue and endometrial glands • Stratum functionalis: Shed during menstruation • Stratum basalis: Replaces stratum functionalis each month • Myometrium • 3 layers of smooth muscle • Perimetrium • Visceral peritoneum Lumen of uterus Uterine Histology ¢ Simple columnar epithelium Endometrial stroma Endometrial gland Stratum functionalis Endometrium 4 Stratum basalis Myometrium 37 Endometrium Simple columnar epithelium Endometrial glands Ovary Histology Mesovarium and blood vessels Vesicular (Graafian) follicle Primordial follicles Oocyte Ovulated oocyte Corpus luteum Developing corpus luteum 40 41 Ovary Histology 42 Zona pellucida 1° Oocyte (arrested in prophase I) Granulosa cellsThecal cells Nucleus Primordial follicle Primary Follicle 45 Ovulation • LH from the pituitary gland will cause the Graafian follicle to rupture • The oocyte will be released (ovulation) • The follicle is now a corpus luteum • Secretes estrogen and progesterone 46 Mammary Glands • Modified sweat glands that produce milk (lactation) • Amount of adipose determines size of breast • Milk-secreting glands open by lactiferous ducts at the nipple • Areola is pigmented area around nipple • Suspensory ligaments suspend breast from deep fascia of pectoral muscles (aging & Cooper’s droop) @-Alveolus ~~ Ductule Lactocyte Copyright € 2004 kellyman.esm 47 Lab Activity 34 Gametogenesis 51 Gametogenesis • Each cell has two sets of chromosomes (one maternal, one paternal) and is said to be diploid (2n chromosomal number) • Humans have 23 pairs of homologous chromosomes • Gametes only have 23 chromosomes and are said to be haploid (n chromosomal number) • Gamete formation is by meiosis, in which the number of chromosomes is halved (from 2n to n) Homologous Chromosomes and Sister Chromatids Centromere Sister A: ij chromatids \ 1 Homologous chromosomes ae | 55 Prophase • First part of cell division • Centromeres migrate to the poles 56 Metaphase • Sister chromatids align in the center of the cell along the spindle that radiates from the centromeres 57 Anaphase • Sister chromatids are pulled toward the poles so that each new cell will get only one copy of the chromosome • The cell begins to elongate 60 Meiosis I Meiosis II Original cell Cell with replicated DNA just prior to starting meiosis Cells at the end of meiosis I (sister chromatids stay together) 61 Prophase I: Synapsis • Homologous pairs of chromosomes undergo synapsis and form tetrads with their homologous partners (4 chromosomes) • Crossover: Genetic material is exchanged between the homologous chromosomes. • Parts of maternal chromosomes may be exchanged with paternal ones • Genetic recombination produces gametes unlike either parent 62 Exchange of Genetic Material • Genes are exchanged between homologous chromosomes 65 Results of Meiosis I • At the end of meiosis I each daughter cell has: • Two copies of either a maternal or paternal chromosome • (Compare to mitosis where you get one copy of maternal and one copy of paternal) • A 2n amount of DNA and haploid number of chromosomes 66 Meiosis II • Mirrors mitosis except that chromosomes are not replicated before it begins • Meiosis II accomplishes two tasks: • It reduces the chromosome number by half (2n to n) • Each of the daughter cells produced by meiosis I divides during meiosis II and the net result is 4 genetically unique haploid cells or gametes. tt. | Ce me Ny ht 67 Spermatogenesis Meiosis {late spermatogenesis) (early spermatogenesis) Spermiogenesis Spermatogonium (stem cell) Spermatogonium Cytoplasm of (stem cell) Basal lamina Daughter cell type A spermatogonium remains at basal lamina as a precursor cell Daughter cell type B spermatogonium Mitosis Growth Enters : meiosis | Moves to adluminal compartment Meiosis | Primary completed spermatocyte Meiosis II Secondary spermatocytes Early spermatids Late spermatids Spermatozoa Tight junction between Cytoplasmic bridge S. Lumen of / seminiferous tubule sustentacular cells sustentacular cells Sustentacular cell nucleus Basal compartment Adluminal compartment Spermiogenesis: Spermatids to Sperm Golgi apparatus Acrosomal vesicle Mitochondria Spermatid Centrioles rm if) nucleus Microtubules —' Midpiece Head (a) @ Flagellum —= 1 ff @ 71 72 Sperm • Sperm have three major regions 1. Head :contains DNA and has a helmet-like acrosome containing hydrolytic enzymes that allow the sperm to penetrate and enter the egg 2. Midpiece: contains mitochondria spiraled around the tail filaments 3. Tail :a typical flagellum produced by a centriole 75 Oogenesis: After Puberty • Each month, hormones cause several follicles to develop, which triggers the primary oocyte to resume meiosis I • Polar bodies: When the cell divides, all the cytoplasm and organelles stay with one of the new cells, the other cell is just DNA, and is called a polar body and is discarded • Secondary oocyte: The stage at which ovulation occurs. 76 Oogenesis: After Puberty • The secondary oocyte begins meiosis II, but stops in metaphase II • The secondary oocyte is ovulated • Meiosis II is completed only if it is fertilized. Oogenesis & Oogonium ® Meiosis | Primary oocyte Secondary oocyte ey @ @ First polar body Vulation y \ YL "@ @ © Sperm + Secondary cell oocyte TN » Ovum y Zygote 2, polar body During fetal development meiosis | begins but stops in prophase. After puberty, primary oocytes complete meiosis |, which produces a secondary oocyte and a first polar body that may or may not divide again. The secondary oocyte begins meiosis || but stops in metaphase. A secondary oocyte (and first polar body) is ovulated. Meiosis II After fertilization, meiosis II resumes. The oocyte splits into an ovum and a second polar body. The nuclei of the sperm cell and the ovum unite, forming a diploid (2n) zygote.