Reproductive System and Fetal Development

Primary sex organs

testes ad ovaries

Produce sex cells (gametes); Secrete steroid sex hormones

Primary sex organs function

Development and function of the reproductive organs, Sexual behavior and drives, and Growth and development of many other organs and tissues

Sex hormones play a role in…

Testes

produce sperm; surrounded by two tunics; divided into 250 to 300 lobules

Male duct system

Epididymis, ductus deferens, ejaculatory duct, urethra, Accessory sex glands, seminal vesicles, Prostate, bulbourethral glands

Two tunics of testes

Vaginalis and Albuginea

1-4

____ seminiferous tubules

Scrotum

Sac of skin and superficial fascia in which testes are contained in to maintain a temperature that sperm production can have in

Portions of penis

root and shaft that ends in glans penis, prepuce or doreskin, curra

Corpus cavernosa and corpus spongiosum

Two types of erectile tissue (males)

Erection

erectile tissue fills with blood leading the penis to enlarge and becomes rigid, Parasympathetic reflex promotes release of nitric oxide (NO)

Epididymis

Stereocilia absorb testicular fluid and pass nutrients to stored sperm; lead sperm to become morile

Ductus deferens

Receives expelled sperm from spididymis, Passes through the inguinal canal, Expands to form the ampulla, the joins the duct of the seminal vesicle to form the ejaculatory duct

Vasectomy

cutting of ducus deferens

Seminal vesicles

Produces viscous alkaline seminal fluid, 70% of the volume of semen, Fructose, ascorbic acid, coagulating enzyme (vesiculase), and prostaglandins

Prostate

Encircles part of the urethra inferior to the bladder; Secretes milky, slightly acid fluid that contains citrate, enzymes, and prostate-specific antigen (PSA), plays a role in sperm activation

Semen

of sperm and accessory gland secretions; contain nutrients, protects and activates sperm, and daciliates movement, alkalinity, antibiotic chemicals

Coagulating favtors

coagulate semen

Fibrinolysin

Liquifies sperm

2-5 ml; 20-150

_____ of semen are ejaculated cotaining ___ sperm\ml

Impotence:

inability to attain erectiion

Ejaculation

Propulsion of semen from the male duct system, Sympathetic spinal reflex; ducs and accesroyglands contract; bladder spincter muscles constrict, bulbospongiosus muscles. undergo rapid contractions

Spermatogenesis

Sequence of events that produces sperm in the seminiferous tubules of the testes; haploid sperm from di[loid spermatigonia

Meiosis

Two consecutive cell divisions (meiosis I and II) following one round of DNA replication; four daughter cells; genetic variation

Head (Nucleus and Acrosome), Midpiece(metabolic region), Tail (Flagellum)

Major regions of sperm

Sustentacular cells

Extend through the wall of the tubule and surround developing cells; provide nutients ad signals to dividing cells, dispose of excess cytoplasm, secrete testicular fluid into lumen for transport of sperm; form blood testis barrier

GnRH

released from hypothalamus and stimualtes anterior pitutary hormones

FSH

____ causes sustentacular cells to release androgen-binding protein (ABP), which makes spermatogenic cell receptive to testosterone

LH

stiumulates interstitial cells to release testosterone

Testosterone

__ is the final trigger for spermatogenesis; also responsoible for libido and secondaru sex characteristics

Stages of ovarian follicles

Primordial follicle, Primary follicle, Secondary follicle, Vesicular (Graafian) follicle

Ovulation

Ejection of the oocyte from the ripening follicle

Ampulla

__ is the usual site of fertilization

Cilliated fibriae

_____ of indundibulum create currents to move oocyte into uterine tube

Persistaltsis and ciliary acrtion

Oocyte is carried by

Perimetrium, Myometrium, and Endometrium

Three layers of uterine wall

Two layers of edometriym

Functional and basal

Functional endometrial layer

Changes in response to ovarian hormone cycles; Is shed during menstruation. Spiral arteries

Vagina

Birth canal and organ of copulation

Vagina histolofy

Fibroelastic edventition, smooth muscle muscularis, and stratified squamous mucos

Portions of vulva

Mons pubis, labia minor, labia majora, vestibule, greater vestiular gland. clitoris, perineum

Greater vestibular glands

Homologous to the bulbourethral glands; Release mucus into the vestibule for lubrication

Clitoris

Erectile tissue hooded by a prepuce; Homologous to penis.

Mammary glands

Modified sweat glands consisting of 15–25 lobes

glandular alveoli that produce milk

Lobules of each mammary lobes contain….

Oogenesis

Production of female gametes

Steps of oogenesis

Infancy and childhood, meosis I (arrested in metaphase until ovulation), meosis II (arrested in metaphase II until fertilization)

Ovum and 3 polar bodies

Oogenesis leads to…

Two cyckes of female reproductive cycle

Ovarian and Uterine

3 phases of uterie cycle

Menstrual, proiferative, secdretory

Ovarian cycle

Monthly series of events associated with the maturation of an egg

Follicular and Luteal

Two phases of ovarian cycle

Follicular phase

Period of follicle growth

Primordial follicle to primary follicl

squamous like cells become cuboidal

Primary follicle to secondary follicle

Stratified epithelium (granulosa cells) forms around oocyte, Granulosa cells and oocyte guide one another’s development

Secondary follicle to late secondary follicle

Connective tissue (theca folliculi) and granulosa cells cooperate to produce estrogens, Zona pellucida forms around the oocyte, Fluid begins to accumulate

Late secondary follicle to vesicular follicle

Antrum forms and expands to isolate the oocyte with its corona radiata on a stalk, Vesicular follicle bulges from the external surface of the ovary, The primary oocyte completes meiosis I

positive feedback

High estrogen exerts ___ on FSH and LH midcyle, causing a surge

LH

surge of __ leads to ovulation

Corpus luteum

Produces inhibin, progesterone, and estrogen to inhibit FSH and LH release

ends luteal activity and inhibits follicle development

Declining LH and FSH …

Menstrual cycke

Ovarian hormones are low, Gonadotropins are beginning to rise. Stratum functionalis is shed and the menstrual

flow occurs

Proliferative phase

Estrogen levels stimulate new functional layer and increased synthesis of progesterone receptors in endometrium.Glands enlarge and spiral arteries increase in number

Secretory phase

Progesterone levels prompt Further development of endometrium, Glandular secretion of glycogen and Formation of the cervical mucus plug

Corpus luteum degenerates, Progesterone levels fall, Spiral arteries kink and spasm, and Endometrial cells begin to die

If fertilization does not occur …

Estrogen

Promote oogenesis and follicle growth in the ovary, Exert anabolic effects on the female reproductive tract, Support the rapid but short-lived growth spurt, Metabolic affects, ecodary sex characteristics

Progesterone

establish and regulate uterine cycle with estrogen

Placental progesterone

Inhibits uterine motility

– Helps prepare the breasts for lactation

Menopause

When menses have cesead for an entire year; lead to a decline in estrogen lebr

Capacitation

the process whereby the ejaculated sperm become capable of fertilizing the egg

Acrosomal reaction

release of digesive enxymes and help of hundreds of sperm to breach an egg

Prevention of polyspermy

Penetration of the egg membrane by the first sperm causes the membrane to depolarize and Ca2+ entering cahses cortical reaction

Completes meiosis II and Casts out the second polar body

Upon entry of sperm, the secondary

oocyte…

morula to blastocyst

Zygote undergoes cleavage to and on to _; should be completed in the uterine tube

Implantation

egg implanting into uterus

2-3

Blastocyst “floats” in the uterus for ___ days

6-7; 14

Blastocyst implants ___ after ovulation and implation is completed by __ days

Cytotrophoblast and syncytiotrophoblast

Trophoblast proliferates into ….

Cytotrophoblast

cells of the inner layer that retain their cell boundaries

syncytiotrophoblast

cells in the outer layer that lose their plasma membranes and invade the endometrium

Chorion

develops from trophoblast after implantation, continues hCG stimulus; develops fingerlike villi that become vascularized, extend to the embryo as umbilical arteries and veins, lie immersed in maternal blood, forms the bulk of the placenta

Ectopic pregnancy

implantation in uterine tube

chorion, allantois, and amnion.

The embryo is supported by three external embryonic membranes: _______

Allantous

a small out pocket at the caudal end of the yolk sac; structual base for the ubillical cord, becomes pat of urinary bladder

Yolk sac

hypoblast cells that form a sac on the ventral surface of the embryo forms part of the digestive tube, produces earliest blood cells and vessels, and s the source of primordial germ cells

Amniotic fluid

comes from maternal blood, and, later, fetal urine adds to it – acts as a liquid shock absorber to protect the fetus – Helps maintain a constant homeostatic temperature – may be sampled to determine certain aspects of fetal health

hCG

____ maintains the corpus luteum which produces estrogen and progesterone (positive eedback)

upper epiblast and lower hypoblast

Before becoming three-layered, the inner cell mass subdivides into the …

primitive streak; endoderm, then mesoderm, then ectoderm

During the 3rd week, a ___ appears that estavlishes longitudal axis of embryo, first cells that enter form ___, then mesoderm, and the cells thay remain on embryos dorsal surface form ___

Ectoderm

forms structures of the nervous system and skin epidermis

Endoderm

forms epithelial linings of the digestive, respiratory, and urogenital systems

Mesoderm

forms all other tissues (all connective tissues, bone, all types of muscle, blood and blood vessels, the gonads and the adrenal cortex)

Neurulation

the first event of organogenesis gives rise to the brain and spinal cord; induced by notochord which ectoderm thickens and forms neural plate

22nd dat

By the ___, the neural folds fuse into a neural tube, which

pinches off into the body,

spina bifida

Incomplete neural tube formation causes ___ and

other neural tube (birth) defects

brain; spinal cord

Anterior end of nerual tube becomes __ and the rest become the

epithelial lining of Gi tract and hollow organs of digetsive and respiratory tracts

ENdoderm tube bforms the

the gonads and kidneys

Intermediate mesoderm forms

dermis of the skin in the ventral region parietal serosa of the ventral body cavity, bones, ligaments, and dermis of the limbs

somatic mesoderm fporms

heart, blood vessels and most connective tissues of the body

splachnic mesoderms forms the