BMS Unit 5 Exam

Gonads

organs that produce gametes and hormones

Ducts

receive and transport gametes

Accessory glands

secrete fluids into ducts

Path of sperm through male reproductive system

testes, epididymis, vas deferens, urethra

Spermatic cord

- begins at entrance to inguinal canal

- descends into the scrotum

- enclose the vas deferens, blood vessels, nerves, and lymphatic vessels of the testes

Inguinal hernia

- protrusion of visceral tissues into inguinal canal

- common in males because spermatic cord creates weak point in abdominal wall

Temperature requirement in the testes

- normal sperm development requires temperatures 1.1 C lower than rest of body

Temperature regulation in the testes

when air or body temp increases

- cremaster and dartos muscles relax, moving testes away to keep them cooler

Seminiferous tubules

- slender, tightly coiled tubules in the lobules of the testes

- location of sperm production

the blood-testis barrier is located between the:

spermatogonia and primary spermatocytes

Mitosis

results in 2 identical cells

Meiosis

results in 4 unique cells

After completion of meiosis II, all gametes are....

haploid

Spermatogenesis

process of sperm production

- begins at puberty

- takes about 64 days

Spermiogenesis

differentiation of a spermatid into a sperm

- approx 24 days

Cell types in testes

- Germ cells

- Leydig cells

- Sertoli cells

Germ cells

produce spermatogonia

Leydig cells

(interstitial cells) synthesize testosterone

Sertoli cells secretions

(nurse cells)

synthesize anti-mullerian hormone, inhibin, androgen binding globulin

Sertoli cell function

- maintain blood-testis barrier (tight junctions)

- secrete androgen-binding protein (keeps testosterone high to support spermatogenesis)

- support spermiogenesis

- support mitosis and meiosis

Epididymis

coiled tube that serves as start of male reproductive tract. Site of:

- sperm storage

- sperm maturation

- recycling of damaged sperm

Structure of epididymis

- Head: largest part that receives sperm produced in seminiferous tubules

- Body: on the posterior surface of each testis

- Tail: begins near inferior border of testis and ascends to connection with the ductus deferens (primary storage location)

Sperm entering the lumen of the seminiferous tubules are:

immature and immotile

Sperm motility post epididymis

sperm leaving epididymis are not capable of coordinated movement or fertilization, must undergo capacitation

Sperm capacitation

- sperm become motile when mixed with secretions of seminal glands

- become capable of fertilization when exposed to the female reproductive tract

Bulbourethral gland

- alkaline mucus to neutralize urinary acids in the urethra

- lubricates tip of penis

Seminal gland

- fructose (nutrient for sperm)

- prostaglandins (stimulates smooth muscle contractions)

- fibrinogen (forms temporary clot in vagina)

- slightly alkaline (neutralize acids in vagina)

- first step in capacitation

Prostate gland

- slightly acidic with enzymes that prevent sperm coagulation in the vagina

Fibrinogen forms a temporary clot in the vagina, and is found in

seminal gland

Exogenous administration of excessive testosterone can eventually lead to male infertility by decreasing the levels of

Gonadotropin-releasing hormone, follicle-stimulating hormone, and luteinizing hormone

In males, you would find receptors for follicle-stimulating hormone on

Sertoli cells

Uterine tubes

- Mucosa consists of ciliated columnar epithelial cells

- Peg cells secrete fluid that completes sperm capacitation

- Nutrient rich for sperm and oocytes

What mechanisms in the fallopian tubes move oocytes to the uterus?

- Ciliary movement

- peristaltic contractions

Uterus

- muscular organ that protects, nourishes, and removes wastes for developing embryos

Cervix

inferior portion of uterus that extends to the vagina

Layers of the uterine wall

- perimetrium

- endometrium

- myometrium

Perimetrium

outer thin layer that covers the surface of the uterus

Endometrium

- inner lining of uterus

- thin, glandular, and vascular

- supports fetus

Myometrium

- thick layer of smooth muscle

- contractions move fetus

Vagina

- highly distensible, muscular tube that extends between cervix and vestibule

Functions of vagina

- passageway for elimination of menstrual fluids

- receives penis

- forms portion of birth canal

- vestibular glands: secrete during sexual arousal

External female genitalia

- clitoris

- labia minora

- labia majora

Clitoris

small projection containing erectile tissue, derived from same embryonic structures as penis

Labia majora

- prominent folds of skin and adipose tissue that encircle and conceal labia minora and adjacent structures

Labia minora

Small folds around vestibule covered with smooth, hairless skin

Mammary glands

- consist of lobes

- each lobe: several secretory lobules separated by dense connective tissue

- mammary gland ducts converge, forming lactiferous duct

Lactiferous sinus

where milk accumulates during nursing

Lactiferous duct

A duct through which milk is secreted and which opens at the nipple

Ovarian follicle

specialized follicle where oocyte grows and matures

Maturation of oocyte in ovary

- Primordial oocytes surrounded by a single layer of squamous cells

- Primary surrounded by simple cuboidal

- Secondary surrounded by stratified cuboidal epithelium

- Tertiary filled with follicular fluid secreted by deeper follicular cells

Oogenesis

- oogonia complete mitotic divisions before birth

- between 3-7 months of fetal development, primary oocytes undergo meiosis but halt at prophase of meiosis I

- during puberty, FSH triggers ovarian cycle

- Meiosis I is completed by LH stimulation

- Fertilization causes Meiosis II completion

Female germ cells enter meiosis I

before birth

Female germ cells complete meiosis II

at fertilization

Menopause

- time that ovulation and menstruation cease

- circulation concentrations of estrogen and progesterone decrease

- increase in GnRH, FSH, LH

Decrease in levels of estrogen during menopause leads to

- reductions in size of uterus and breasts

- thinning of urethral and vaginal epithelia

- reduction in rate of bone deposition

Which uterine phase is marked by the initial buildup of endometrium in response to rising estrogen levels?

Proliferative phase

High levels of GnRH will lead to an increase in

FSH, testosterone, inhibin

High levels of estrogen from the dominant follicle cause a _____ feedback to the hypothalamus that leads to ______ levels of luteinizing hormone

positive feedback, increased

Contraceptive types

- short acting

- long acting

- hormonal

- non hormonal

Hormonal contraceptives

- pills

- patch

- ring

- some IUDs

- injection

Combined hormone contraceptives

- contain synthetic estrogen and progesterone

- exposure to estrogen and progestin for 3 wks followed by a 1 wk break

Mechanism of estrogen/progesterone based contraception

- hormones impair folliculogenesis, and inhibit ovulation

- exposure is sufficient to induce endometrial development

- removal of exposure is sufficient to induce menses

Progestin-only contraception

- mini-pill

- injection

Mechanism of progestin-only contraception

- exposure to progestin impacts folliculogenesis

- thicken cervical mucus, blocking sperm

- impair endometrial development

- prevent ovulation (variable between individuals)

Long-term reversible contraceptives

- hormonal IUD (Kyleena, Mirena, etc)

- implant

- copper IUD (Paragard)

Mechanism of IUD (hormonal)

- releases progestin into uterus

- thickens cervical mucus to block sperm

- thins uterine lining

- may prevent ovulation

Mechanism of IUD (copper)

- mechanical barrier that blocks sperm from reaching and fertilizing egg

- prevents implantation

- doesn't inhibit ovulation

Mechanism of implants

- release progestin up to 3 years

- thickens cervical mucus, thins uterine lining, may prevent ovulation

Emergency contraception

- IUD

- morning after pill

Levonorgestrel (LNG)

- synthetic progestin

- blocks LH surge and delays ovulation

- less effective in those > 155lbs

Ulipristal acetate

- progesterone receptor modulator

- blocks LH surge and ovulation

- greater efficacy in those > 155lbs

- lower efficacy in those > 195 lbs

Which of the following acts as a contraceptive by directly inhibiting a hypothalamic hormone?

- FSH

- estrogen

- progesterone

- luteinizing hormone

Progesterone

Trichomoniasis

- protozoan

- antibiotics

Chlamydia

- bacterial

- antibiotics

Syphilis

- bacterial

- antibiotics

- cannot undo damage already done

Genital HPV

- human papillomavirus

- cannot be cured, rather managed and treated

HIV

- human immunodeficiency virus

- if untreated, progress to AIDS

Gonorrhea

- bacterial

- antibiotics

- resistant strains increasing

Which of the following STDs is caused by a bacteria?

- Trichomoniasis

- Syphilis

- Genital HPV

- AIDS

Syphilis

Who is at risk for STDs?

- college age people (chlamydia, gonorrhea, syphilis, HPV)

- elderly (lack of condom bc no pregnancy)

Levels of sex determination

- genetic (XY, XX)

- gonadal (Testes, ovaries)

- phenotypic (external genitalia, glands, tracts)

Genetic sex determination

- Chromosomes (23rd pair, XX or XY)

- autosomes (22 pairs)

- X chromo (need 1)

- Y chromo (SRY gene for males)

Gonadal development is ONLY dependent on ........

genes

Ovary development

RSPO1, beta-catenin, and WNT4 are active and block SOX9

Testis development

SRY upregulates SOX9, which blocks RSPO1, B-catenin, and WNT4

Gonadal sex determination

- undifferentiated until 6th week of development

- bipotential (can be ovary or testis)

- RSPO1, B-catenin, WNT4, and SOX9 are autosomal factors on every cell

RSPO1/WNT4 is responsible for:

a. initiating puberty

b.triggering ovulation

c. development of an ovary

d.maintenance of the corpus luteum

Development of an ovary

Mullerian duct

- female reproductive tract progenitor

- differentiates into oviduct, uterus, cervix, and vagina

Wolffian duct

- male reproductive tract progenitor

- differentiates into epididymis, vas deferens, seminal vesicle

Alfred Jost experiments

- embryos without gonads (regardless of genetic sex) acquired a female phenotype

- regression of Wolffian ducts and maintenance of Mullerian ducts

What maintains the Wolffian ducts?

testosterone

What is required to maintain the Mullerian ducts?

nothing

What is released by the testes for the regression of the mullerian ducts?

Anti-Mullerian hormone (AMH)

Which of the following is TRUE?

a. Anti-Mullerian hormone (AMH) is necessary for the development of the Mullerian duct

b. Estrogen is necessary for the development of an ovary

c. Testosterone is necessary for the development of a testis

d. Chromosomal sex determines gonadal sex, which then determines phenotypic sex

Chromosomal sex determines gonadal sex, which then determines phenotypic sex

Phenotypic sex determination

- ovaries secrete estrogen and progesterone, leading to development of the breasts, uterus, vagina, and ovaries

- testes secrete testosterone and AMH

How does external genitalia differentiate?

- initially undifferentiated

- feminization is default (forms vaginal opening, labia minora/majora, and clitoris)

- Masculinization requires dihydrotestosterone (DHT) which forms penis, urethra, and scrotum

Which of the following does not develop from the Mullerian duct?

- uterus

- uterine tubes

- cervix

- lower vagina

lower vagina

A mutated Y chromosome that lacked an SRY gene would lead to the:

- degradation of the Wolffian duct

- development of testes

- activation of SOX9

- masculinization of external genitalia

degradation of the Wolffian duct

Turner Syndrome

- XO

- Ovaries

- Internal: Mullerian (no AMH or T)

- External: feminization (no DHT)

Klinefelter Syndrome

- XXY

- Testes

- Internal: Wolffian duct (AMH + T)

- External: masculinization (DHT)