Sexual Reproduction

• Sexual reproduction is the process by which organisms create offspring by uniting gametes, such as sperm and egg.
• Male reproductive organs produce gametes in the form of sperm, secrete androgen hormones, and facilitate fertilization.
• Female reproductive organs produce gametes in the form of ova, secrete female hormones, facilitate fertilization, and sustain the growth of the embryo and fetus.
• The gonads, testes in males and ovaries in females, are responsible for gamete production and hormone secretion.
• Ducts play a role in storing and transporting gametes.
• Accessory sex glands create secretions to protect gametes and assist in their movement.
• Supporting structures function in the delivery of gametes.
• Gynecology is the medical specialty focused on treating disorders and diseases of the female reproductive system.
• Obstetrics specializes in the care of women during pregnancy.
• Urology is the medical specialty focused on treating disorders of the urinary system, including disorders involving the male reproductive system.

Male Reproductive System Anatomy

• Male gonads are the testes.
• Ducts of the male reproductive system are the ducts of the testis, epididymis, vas deferens, ejaculatory ducts, and urethra.
• Male accessory sex glands include seminal vesicles (2), prostate (1), and bulbourethral glands (2).
• Male supporting structures include the penis, scrotum, and spermatic cord.
• A white fibrous capsule, known as the tunica albuginea, surrounds each testis and forms septa that divide each testis into 200-300 compartments called lobules.
• Each lobule contains 1-3 seminiferous tubules, which are the sites of sperm production.

Spermatogenesis

• Spermatogenesis, the process of sperm formation, begins at puberty and continues throughout life.
• In humans, spermatogenesis usually takes between 65-75 days.
• Follicle-stimulating hormone (FSH) and testosterone stimulate spermatogenesis.
• Spermatogenesis starts with diploid (2n) stem cells called spermatogonia and ends with haploid (n) spermatozoa.
• Spermatogenesis occurs in the seminiferous tubules, beginning in the outer region of each tubule, maturing closer to the lumen of the tubule as the cells mature.
• Each day about 300 million sperm complete spermatogenesis that includes structures highly adapted for reaching and penetrating a secondary oocyte.
• Sperm head contains the nucleus with 23 highly condensed chromosomes.
• The acrosome is a cap-like vesicle that covers the anterior two-thirds of the nucleus which is filled with enzymes that help a sperm to penetrate a secondary oocyte to bring about fertilization.
• The tail contains 4 parts: the neck, middle piece, principal piece, and end piece. The middle piece contains mitochondria to provide the energy (ATP) for locomotion.

Hormonal Control of Spermatogenesis

• Unknown initiating factors at puberty causes the hypothalamus to increase the secretion of gonadotropin-releasing hormone (GnRH).
• GnRH in turn increases release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary.
• LH stimulates Leydig cells, which are located between seminiferous tubules, to secrete testosterone, which then directly stimulates the final steps of spermatogenesis.
• FSH and testosterone stimulate Sertoli cells to release androgen-binding protein (ABP)
• ABP binds to testosterone, ensuring that testosterone levels remain high in the seminiferous tubules, indirectly stimulating spermatogenesis.

Additional Androgen Effects

• Prenatal secretion of testosterone assists testicular descent.
• DHT is responsible for the development of male external genitals during prenatal development.
• Testosterone and DHT at puberty lead to the development of male sexual characteristics.
• Androgens contribute to male sexual behavior and contribute to sex drive in both males and females.
• Androgens are anabolic hormones that stimulate protein synthesis.

Male Reproductive System Ducts

• After formation in the seminiferous tubules, sperm travel through straight tubules, rete testis, efferent ducts, and epididymis
• Sperm maturation, gaining motility and the ability to fertilize an ovum, occurs in the epididymis where sperm may also be stored for up to several months.
• Sperm then travels through vas deferens and ejaculatory ducts
• Lastly, sperm travels through urethra which consists of 3 regions in order, prostatic, membranous, and spongy (penile).
• Semen is defined as being a mixture of sperm and seminal fluid.
• Semen volume in a typical ejaculation is 2.5-5 milliliters (mL), with 50-150 million sperm per mL
• If sperm falls below 20 million/mL, the male is likely to be infertile.

Male Accessory Sex Glands

• Most of the fluid portion of semen is from the male accessory sex glands, specifically the seminal vesicles, prostate, and bulbourethral glands.
• The seminal vesicles secrete a viscous, alkaline fluid (mainly during ejaculation) which makes up 60% of the total semen volume.
• Seminal vesicles secrete fructose, prostaglandins, and clotting proteins, where prostaglandins stimulate smooth muscle contractions
• The the alkalinity neutralizes the acidity of the male urethra and the female reproductive tract
• The prostate is chestnut-sized gland that secretes about 25% of semen volume which includes contains citric acid, acid phosphatase, and proteolytic enzymes
• The bulbourethral glands are pea-sized glands inferior to the prostate and secrete a protective alkaline mucus.
• The alkaline mucus decreases sperm damage in the urethra

Male Anatomy

• The scrotum is the supporting structure for the testes that consists of a sac of loose skin and superficial fascia hanging from the root of the penis
• The location and contraction of muscle fibers (dartos and cremaster muscles) regulates testicular temp to that required for sperm production (2-3°C below the core temp)
• The spermatic cord is a supportive structure that ascends out of the scrotum.
• The spermatic cord consists of the ductus deferens, testicular artery, veins, autonomic nerves, lymphatic vessels, and the cremaster muscle
• The spermatic cord and ilioinguinal nerve pass through the inguinal canal which is a passageway in the aponeuroses of the abdominal muscles

Penis

• Penis contains the urethra and is a passageway for the ejaculation of semen and the excretion of urine
• It is cylindrical in shape and consists of a body, glans penis and a root that is supported by the fundiform ligament and the suspensory ligament
• Body of the penis is composed of three cylindrical masses of erectile tissue covered tunica albuginea
• The two dorsolateral masses are the corpora cavernosa and the smaller midventral mass is the corpus spongiosum (contains the spongy urethra and keeps it open during ejaculation)

The Male Sexual Response

• Upon sexual stimulation, sacral parasympathetic fibers initiate and maintain an erection.
• Nitric oxide dilates arteries that supply the penis, allowing blood to enter a network of sinuses in the erectile tissue, also relaxing the smooth muscle resulting in widening of blood sinuses
• After an erection, sympathetic stimulation is necessary for the rest of the sexual response, including ejaculation.
• During ejaculation, the smooth muscle sphincter at the base of the urinary bladder must close, followed by semen being propelled into the penile portion of the urethra
• Peristaltic contractions culminate in the release of semen from the urethra to the exterior

Female Reproductive System

• Female gonads are the ovaries.
• Ducts of the female reproductive system are the uterine tubes.
• Female accessory sex glands are the Paraurethral, Greater vestibular, and Lesser vestibular glands
• The female supporting structures are the uterus, vagina, and vulva.

Ovaries

• The ovaries are oval-shaped organs held in place in the pelvic cavity by the suspensory ligaments and the ovarian ligaments.
• Germinal Epithelium-covers the surface of the ovary, but does not give rise to ova.
• Ovarian Cortex-contains the ovarian follicles.
• Ovarian Medulla-contains blood vessels, lymphatic vessels and nerves.
• Primary role of the ovaries are to produce mature oocytes (female gametes) and release during each monthly cycle.
• Secrete estrogen, progesterone, inhibin and relaxin.

Uterine Tubes

• Upon receiving 2o oocytes, the uterine tubes provide a site for fertilization.
• If fertilization occurs, the 2o oocyte becomes an mature egg.
• Uterine tubes also have an ampulla (widest, longest point)
• Uterine tubes also have isthmus which helps them to join is to the uterus.
• The uterus is a pear-shaped organ situated between the urinary bladder and the rectum and its functions include providing pathways so sperm reaches uterine tubes.
• Site of implantation of an ovum
• If no implantation uterus = the source of menstrual flow.

Uterus Ligaments

• Broad Ligaments provide support to the uterus by attaching it to the pelvic cavity.
• Uterosacral Ligaments attach to the sacrum
• Fundus- the upper portion known as the anatomical subdivisions of the uterus.
• Body- central portion tapers to narrow isthmus within uterus.
• Cervix- Inferior portion and inside is the cervical canal with internal os and external os.

Uterus Wall

• Endometrium- Inner stratum that sheds during menstruation.
• Myometrium- Includes inner and outer layers with longitudinal running muscle.
• Perimetrium -part of visceral peritoneum.
• The vagina extends to the exterior of the body to the uterine cervix and 3 basic functions serves as menstrual flow, Penis during sexual and lower birth canal.

Vulva Anatomy

• The vulva is female eternal genitalia and made up of mon pubis
• Labia majora (outer limits of vulva), labia minora(covers the vestibule) , clitoris has erectile tissue
• Vestibule - area between the labia minora , hymen, vaginal orifice+ glands
• Glands of the vestibule include Paraurethral (Skene's) glands secrete mucus.
• Homologous to prostate gland in males, greater vestibular (Bartholin) glands lubricating with mucus and analogous to bulbourethral.
• Preineum is diamond shaped media to the thighs and buttocks in external genitalia and anus.

Mammary Glands

• Modified sudoriferous gland that produces milk.
• Consists of 15 to 20 divided lobes with lobules milk secreting glands in alveoli.
• The milk then travels through the ducts exiting via lactiferous ducts located in the nipples.
• Similar to the male the origin sexual response is stimulation of sacral parasympathetic fibers and nitric oxide dilation.
• Sexual climax creates systemic discharge and contraction in the pelvic area.

Oogenesis

• The oogenesis process involves cells in ovarys
• Oogenesis begins in females when in birth unlike males where puberty takes affect
• The gametes devlope in cells and that process is known and follicular development.
• The gametes are estrogenic and progestin.

More Oogenesis Notes

• Germ cells move to the ovaries migrate and morph into oogonia .
• These ogonia are divided and make themselves.
• There is a prophase and meiosis aspect of gametes and ootcytes , oocytes are surrounded by flat folliculal cell.
• At puberty this cycle decreases its production and begins to be controlled by anterior pituitary.
• Primary follicles differ because primary follicles have a clear layer and granolas cells.
• Thera are always stromal cells around the basement.

Oogenesis and Maturation

• There are different phases of follicular devlopment.
• With continuing maturation the primary follicles develop into the secondary follicles.
• Granola cells secrete fluids that develop a cavity.
• And innermost layer is then now called corona radiata and the other layers are still theca
• The mature follicle ruptres at mesophase 2 and ovulation begins and the oocyte matures.

Female reproductive cycle

• From menarche to menopause there is a cycle roughly around 28 days
• Ovarian cycle creates secoundary oocytes , which prepares for the female system for a potential fertilsation.
• Hormonal cycle is controlled by the hypothalamus
• Note the term female cycle involves uteran and orvarian with its changing breast cycles.
• GnRH stimulates cycle releases FSH and LH by anterior pituitary to activate estrogen.
• This then cause mid-cycle LH surge and promotes formation and release of Progesterone and relaxin and inhibin

Estrogen and progesterone and female cycle

• Estrogens help develop structure , 2nd characteristics and even increase protein but lower blood cholersterol.
• Progesterone is repsonsible to mature uterine and branst is inhibited through a negative feedback loop
• Relaxion is released during pregnancy/birth.
• These key phases determine specific female stages by 28 day cycle/ menstural is between 1 and 5 , then ovulation 14 with post ovulatory being 15.

Reproductive Cycle events and hormones

• Menstrual 1-5: FSH causes primordial ovaries release lining
• Prevulatory 6-13 Dominat follicle increase strogen causing mature follicle , which stimulates endorium repair.
• Lastly we have progesteron to increase endometrial lining.
• When the cycle does not occur Human chorionic hormone rescues cycle
• When it does not hormones decrease

Birth Control methods and abortion

• The best method to avoid is total abstinence.

• surgical

• hormonal

• Spermacides or barriers

• periodic Lastly abortion is premature

• Development starts with intermediate

• Wolffin = males mullein males

• With testosterone = male no test= female

• Hometogous is equal parts like testis ovaries equal

Systems over life

• Females is menstral from meanrche to menopause then in older men reproductive funcntio decreases
• As so does muscle strength and prostate disorders become more common

Issues w/ female reproductive disorders

• Lastly dysfunction is abnormal bleeding usually estrogen imbalance.
• STD can induce peritonitis and salpingitis.

Sexual reproduction merges gametes from male and female reproductive systems. Male organs produce sperm and androgens and facilitate fertilization. Female organs produce eggs and hormones, also nurturing the embryo and fetus.