Chapter 27 Reproduction

Role of Sertoli cells

(aka sustentacular): supporting cells Provide nutrients, fluid for sperm transport, signals for spermatogenesis

Name the muscles involved in temperature regulation of the testes

-Cremaster muscle keeps testes ~3° cooler than body temp -Dartos muscle wrinkles scrotum to increase SA and conserve heat

Define vasectomy and how it is performed

-Cutting the ductus (vas) deferens -Male continues to make sperm and testosterone, but sperm can't exit body -Other secretions are still ejaculated

Relate the stages of mitosis to oocyte development

-Eggs start meiosis, but arrest in prophase I (primary oocyte) -Development resumes at puberty, when FSH stimulates some to complete meiosis I (secondary oocyte) -Remains a secondary oocyte unless fertilized, then becomes an ovum

Describe the hormones involved in the ovarian and uterine (menstrual) cycles

-GnRH (causes rising levels of FSH and LH) -FSH (and LH ensure only one oocyte matures at a time) -LH ( causes follicle to rupture or ovulate and then repairs it) -Estrogen (act as negative or positive feedback to reduce or increase FSH and LH) -Progesterone (Inhibits FSH and LH)

Days 1-5: Menstrual Phase

-Hypothalamus releases GnRH, which causes rising FSH and LH levels -Stratum functionalis detaches from uterine wall and is shed (menstrual flow 3-5days) -Growing ovarian follicles (specifically, follicular cells) start producing estrogen

Name the different types of cells that make up the testes and their roles

-Interstitial Endocrine Cells-Aka Leydig cells: secrete androgens (testosterone) into IF -Myoid Cells-Squeeze sperm and fluids thru tubules and out of testes -Spermatogenic cells in tubule epithelium-produce sperm

Prostate

-Milky secretion, slightly acidic -Contains citric acid to nourish the sperm -Contains antibacterial protein

Fertilization

-Occurs high in fallopian tube -Must occur within 24 hours of ovulation -Sperm can remain viable for up to 6 days -Female haploid nucleus + male haploid nucleus = zygote

Seminal Vesicles

-Secrete alkaline solution to neutralize vaginal acid -Contains FRUCTOSE to nourish sperm -Contains PROSTAGLANDINS to enhance sperm motility and decrease viscosity of cervical mucus

Bulbourethral gland

-Secretes thick, clear solution prior to ejaculation -Neutralizes acids and cleans urethra of residual urine -Lubricates the penis

Testes blood supply

-Testicular arteries -Pampiniform venous plexus: absorbs heat before it reaches testes

Describe the hormonal regulation of spermatogenesis

1. Hypothalamus releases GnRH 2. GnRH causes anterior pituitary to secrete FSH and LH 3. FSH stimulates spermatogenesis indirectly by causing Sertoli cells to release androgen-binding protein (ABP) 4. LH binds to Leydig cells causing them to release testosterone 5. Testosterone also stimulates development/maintenance of secondary sex characteristics 6. Rising testosterone levels inhibit GnRH secretion from hypothalamus and inhibit gonadotropin (FSH and LH) release from anterior pituitary 7. Sertoli cells secrete inhibin when sperm count is high, which inhibits GnRH and FSH release

Discuss the stages of follicular development

1. Primordial follicle: squamous-like follicle cells + primary oocyte 2. Primary follicle: Cuboidal/columnar follicle cells + primary oocyte 3. Secondary follicle: 2+ layers of follicle cells (now granulosa cells) + primary oocyte; zona pellucida forms 4a. Early vesicular follicle: antrum (fluid-filled space) begins to form 4b. Vesicular/Graafian/tertiary follicle: antrum formed, follicle bulges 5. Ovulation: follicle ruptures, secondary oocyte ovulated 6. Corpus luteum: develops from ruptured follicle after ovulation; degenerates leaving scar tissue

Describe the process of oogenesis, including each stage the oocyte undergoes during the ovarian cycle.

1. The germinal epithelial cells divide repeatedly until many diploid oogonia are formed 2. The oogonia grow to form primary oocytes that are surrounded by a layer of follicle cells. 3. The oocytes undergoes the first meiotic division to become a secondary oocyte and a first polar body. (haploid) 4. The follicle cells surrounding the primary follicle develop into the secondary follicle. -The follicle layer of the secondary oocyte thickens and folds to form the Graafian follicle. -When the Graafian follicle become matures, it will move towards the surface of the ovary wall and rupture to release the secondary oocyte(n). 5. The secondary oocytes that has complete meiosis II when it is fertilized by a sperm. The final product of meiosis II is the ovum and the second polar body.

Describe cervical cancer risks and prevention

Affects 450,000 women/year killing 50% Most common ages between 30-50 Risks: frequent cervical inflammation, STI's (including HPV) Papanicolaou (Pap) smear for detection -Recommended every 3 years for ages 21-30

Explain the process of spermatogenesis

Begins ~14yr olds, often earlier Takes 64-72 days -Spermatogonia (stem cell) --> Type B cell -->Primary spermatocyte --> Secondary --> Spermatid --> Spermatozoa (sperm)

Hormones: FSH and LH

Both released by anterior pituitary Functions of FSH -Initiates follicular growth Functions of LH -Stimulates ovulation and promotes formation of corpus luteum

Describe the two layers of the ovarian capsule

Capsule contains germinal epithelium (simple squamous/cuboidal epithelium) and a tunica albuginea (dense irregular CT)

Clamydia

Chlamydia bacterial (Chlamydia trachomatis) Symptoms Female: often no signs or symptoms ("silent STD"), possible discharge, irregular menses Male: Urethritis, testicular pain, discharge If left untreated: common cause of PID, could lead to sterility Treatment antibiotics

Describe the average number of sperm/mL and when the count is indicative of sterility

Contains ~ 20 - 150 million sperm/mL -- Fewer than 20 million/mL = sterile

Days 15-28: Secretory Phase

Corpus luteum secretes progesterone which: -Inhibits FSH and LH -Thickens endometrium -Causes nutrient secretion into uterus -Causes mucus thickening and formation of cervical mucus plug --prevents entry of sperm, pathogens, debris If fertilization doesn't occur: progesterone slows, then stops causing thickened endometrium to slough off (menstruation)

Function of the penis

Deliver sperm into female reproductive tract

Testes Structure

Develop in the abdomen and descend through the inguinal canal into the scrotum

Accessory Sex Organs

Ducts, glands, external genitals: transport gametes, produce supportive substances

Explain the process of spermiogenesis

Final stage of Spermatogenesis, takes place when Spermatids lose excess cytoplasm and form tails, sees the maturation of spermatids into mature, motile spermatozoa.

Discuss the structure and function of the mammary glands

Function: milk production to nourish newborn Milk: alveoli -->lactiferous ducts --> lactiferous sinuses --> out of nipple

Gonorrhea

Gonorrhea AKA "the clap" Bacterial (Neisseria gonorrhoeae) Can be passed vertically during birth Symptoms Female: increased discharge, burning sensation while urinating; can lead to PID and sterility Male: burning sensation while urinating, white/yellow/green discharge Treatment antibiotics

Describe the structure and function of sperm components

Head of Sperm -Acrosome-Modified lysosome contains enzymes required for fertilization -Nucleus-Contains male DNA Tail of Sperm -Mitochondria-for energy to swim to eggs -Flagella-for locomotion to egg

Name the ligaments holding the ovaries in place

Held in place by ovarian, suspensory, and broad ligaments

Herpes Simplex Virus 2 (HSV-2)

Herpes Simplex Virus 2 (HSV-2) viral Characterized by latent periods and flare-ups Can be passed to fetus and cause malformations Only 15% display signs of infection Symptoms Herpes lesions Treatment Acyclovir and other antiviral drugs

Human Immunodeficiency Virus (HIV)

Human Immunodeficiency Virus (HIV) viral Characterized by latent periods and flare-ups Can be passed to fetus and cause malformations Symptoms Flu-like symptoms weeks after exposure Can progress to AIDS Treatment Antiviral drugs

Human Papilloma Virus (HPV)

Human Papilloma Virus (HPV) viral 2nd most common STI in US 80% of cervical cancer linked to strains of HPV Most strains do not cause cancer Symptoms Warts (genital, mouth, throat) Treatment Difficult and controversial Cryotherapy for warts

Describe the location, structure, and function of the cervix

Location/ Structure: Narrow outlet of uterus which leads to vagina Structure:Composed of three layers Function:Cervical glands: secrete mucus that prevents spread of vaginal bacteria from entering uterus and blocks sperm entry (but thins out around ovulation to allow sperm entry)

Describe the location, structure, and function of the ovaries

Location: Left and right side of uterus on the ends of the fallopian tubes Structure: 2X the size of an almond, Capsule, Cortex, Medulla Function: make eggs and hormones

Describe the location, structure, and function of the vagina

Location:Below the cervix Structure:Vaginal walls have: mucosa, muscularis, adventitia Stratified squamous epithelium to withstand friction >>>Rugae to stimulate penis<<<< Hymen = partial covering over opening formed by mucosal folds Function: Female copulatory organ and passage for menstrual blood and baby

Describe the location, structure, and function of the uterus

Location:Opening before the cervix Structure:Made of 3 layers of smooth muscle to propel baby from uterus Function:Baby implants here

Describe the location, structure, and function of the uterine tubes

Location:Right and left side of Uterus and connects to the ovaries Structure: aka fallopian tubes or oviducts Function:Delivers ovulated egg from ovary to uterus (peristalsis) and site of fertilization

Days 6-14: Proliferative Phase

Low (but RISING) levels of estrogen act as negative feedback -FSH and LH secretion are reduced to ensure only one oocyte matures at a time HIGH estrogen levels act as positive feedback -FSH and LH are secreted more -Surge in LH causes follicle to rupture (ovulation) -LH repairs the ruptured follicle corpus luteum

Describe the anatomy of the female external genitalia and their counterparts in the male (See Slide 16)

Mons Pubis-Protective fatty layer over pubic symphysis Clitoris (glans)-Counterpart of male glans penis; contains numerous nerve endings Labia Majora-Counterpart of male scrotum Opening of the duct of the greater vestibular gland-Release mucus into vestibule for lubrication

Describe the common forms of birth control and list them according to effectiveness

Most effective--->Least effective 1/100 women in a year -Implant -Intrauterine Device -Male/Female Sterilization 6-12/100 women in a year -injectable -pill -patch -ring -diaphragm 18+/100 women in a year -male/female condom, withdrawal, sponge, fertility awareness based methods, spermicide

Compare and contrast normal vs. ectopic pregnancy

Normal Pregnancy- The egg implants in the uterus Ectopic Pregnancy- The egg implants in the fallopian tube

Path of the Oocyte: If fertilization occurs:

Ovary --> fallopian tube (about a week)--> implant into uterine wall

Path of the Oocyte: If fertilization doesn't occur:

Ovary --> fallopian tube -->uterus --> cervix --> vagina Shed w/lining of the uterus called endometrium

Primary Sex Organs

Primary Sex Organs Gonads (testes and ovaries): make gametes (oocytes and sperm) and secrete hormones

Discuss the physiological effects of progesterones

Secreted by corpus luteum Functions -Prepare and maintain endometrium for implantation of fertilized ovum -Prepares mammary glands for milk secretion -High levels of progesterone inhibit secretion of GnRH and LHt

Discuss the physiological effects of estrogens

Secreted by follicular cells Functions -Promote development of female reproductive structures -Moderate levels of estrogens inhibit release of GnRH by the hypothalamus and secretion of LH -Faciliatate calcium uptake (stronger bones)

Discuss the physiological effects of gonadotropins (FSH and LH)

Secreted by hypothalamus Functions -Stimulate release of FSH and LH from anterior pituitary gland -Inhibited by progesterone (which is high during pregnancy or when taking certain hormonal birth control medications)

Relative proportion of semen components and characteristics

Semen = sperm + secretions from seminal vesicles (~70%) and prostate (~30%) Characteristics: -- ~2-5 mL/ejaculation -- Milky white -- pH = 7.5

3 accessory glands of male reproduction

Seminal Vesicles Prostate Bulbourethral gland (aka Cowper's glands)

List the structures sperm must travel through to exit the body

Seminiferous tubules --> straight tubules --> rete testes --> efferent duct --> epididymis --> ductus (vas) deferens --> ejaculatory duct --> urethra

Testes function

Sperm and hormone secretion

Syphilis

Syphilis bacterial (Treponema pallidum) May or may not become dormant Symptoms Infected fetus can be stillborn Asymptomatic infection for 2-3 weeks If left untreated: non-itchy rash at infection site, joint pain, possible blindness, heart problems, CNS dysfunction, death Treatment penicillin

List the components of a follicle

immature follicle surrounded by follicle and granulosa cells

Importance of testes being located in the scrotum

to maintain the correct temperature to produce sperm