Reproductive System

Sex Determination

occurs around the 7th week of gestation

SRY gene; Y chromosome

presence of ____ on the ______ will trigger genes essential for male development

seminiferous tubules

sperm is produced in the ________ of testes through meiosis

Sertoli cells; Leydig cells

______ and _____ aid with sperm development

nucleus; digestive enzymes

The head of the sperm contains the ______ and is covered in _______ to penetrate the egg’s membrane

Tail of Sperm

flagellum for swimming

Middle of Sperm

filled with mitochondria for energy

40 million sperm

there are ______ per milliliter of ejaculate

100 sperm

less than ______ reach the egg

epididymis; vas deferens

sperm are stored in the ______ and _______ until they are used

urethra

during arousal, sperm enter the ______, which runs through the penis

Penis

cylindrical organ in front of scrotum, filled with erectile tissue that fills with blood to cause erection for copulation

Semen

sperm-containing fluid produced by glands around the urethra

Ejaculation

_____ occurs at peak sexual arousal

Contractions; penis

_________ of the epididymis, vas deferens and _____ force semen out the tip of the penis

Orgasm

a rush of pleasure hormones

Refractory Period

occurs after ejaculation; erections cannot occur immediately

Review Meiosis

Testes

make sperm via meiosis

also produce testosterone

Seminiferous Tubules

site of meiosis and sperm formation

Testosterone

the male hormone

responsible for many of the male characteristics

responsible for male pattern baldness

Epididymis

collects mature sperm which is eventually propelled the vas deferens

Vas Deferens

sperm travel through this tube, joins the urethra

Vasectomy

the tube is cut to prevent sperm leaving

can be done in doctor’s office

Foreskin

hood of skin covering the head (glans) of penis

Circumcision

foreskin is surgically removed, exposing the end of the penis

Prostate

gland that produces a fluid that carries sperm during ejaculation

it surrounds the urethra

Digital Rectal Exam

doctors use the _______ as a relatively simple test to check the prostate

Benign Prostate Hypertrophy

prostate enlarges with age, slowing the flow of urine

Spermatogenesis Location

occurs in the walls of seminiferous tubules

Spermatogenesis 1st Step

Spermatogonial stem cells (SSCs) reside in the peripheral walls of seminiferous tubules

Spermatogenesis 2nd Step

As SSCs differentiate, they migrate towards the center

Spermatogenesis 3rd Step

commitment to differentiation is followed by several rounds of mitotic division to make up the primary spermatocytes

Spermatogenesis 4th Step

there will be two meiotic divisions to generate the haploid spermatozoa

self-renew; differentiate

SSCs will either _____ to keep the population or ______

Breast (External Structure)

contain mammary glands

Vulva (External Structure)

external genitalia

Clitoris (Vulva)(External Structure)

erectile tissue, sensory function

Labia Majora (Vulva)(External Structure)

external folds of tissue

Labia Minora (Vulva)(External Structure)

folds of tissue within the labia majora

Vestibular Glands (Vulva)(External Structure)

lubrication

Ovaries (Internal Structures)

egg-producing organs contained within the abdominal cavity

Fallopian tubules (Internal Structures)

carry immature oocytes (egg cells) from ovaries to uterus

Uterus (Internal Structures)

thick-walled, muscular organ that carries embryo during gestation

Cervix (Internal Structures)

narrow end of the uterus

Endometrium (Internal Structures)

vascular lining of uterus

Vagina (Internal Structures)

tube leading from uterus out of body, through which offspring are delivered

Follicles

oocytes are produced in the _______ of ovaries through meiosis

provide nourishment and protection

Follicle Retention

females contain 2 million follicles at birth

300,000-400,00 left by puberty

only about 400 mature and get ovulated

Ovulation

mature follicle ruptures at surface of ovary, releasing oocyte into the fallopian tube

month to month

Each ovary alternates ovulation ________

Corpus Luteum

following ovulation, the follicular tissue that surrounded the egg grows into a solid mass

Corpus Albicans

scar tissue of corpus luteum after egg is released and fertilization doesn’t occur

Oogenesis 1st Step

Oogonium goes through several rounds of mitosis

Oogenesis 2nd Step

primary oocytes will start meiosis and arrest in prophase I prior to birth

Oogenesis 3rd Step

after puberty hormones will cause development of a number of follicles

Oogenesis 4th Step

primary oocyte will finish meiosis I

At meiosis I (oogenesis)

______ unequal division, polar body dies

Oogenesis 5th Step

secondary oocyte will arrest in metaphase II

At metaphase II

______ oocyte is released and travels to the uterus

Oogenesis 6th Step

If fertilized, it will complete meiosis II

Identical Twins

single zygote splits

share one placenta

have the same genetics

Fraternal Twins

develop from fertilization of two individual eggs

babies are not the same

Estrogen

responsible for the appearance of secondary sex characteristics of females

promotes function of sex organs

affects body hair and fat distribution

wider hips for safer delivery of offspring

Progesterone

regulates menstration

promotes endometrial growth

Days 1-5 (Menstrual Cycle)

low levels of sex hormones, endometrium disintegrates and is released during menstruation

Days 6-13 (Menstrual Cycle)

estrogen increases, causing endometrium to thicken again

Day 14 (Menstrual Cycle)

ovulation occurs

Days 15-28 (Menstrual Cycle)

Progesterone causes endometrium to double in thickness and secrete mucus, ready to receive an embryo

menstrual cycle starts over

If pregnancy does not occur _______

Menstruation

if no fertilized egg reaches the uterus, the lining is shed monthly

Zygote

fertilized ovum (egg)

The Menses Phase

phase where lining is shed

occurs in early days of follicular phase when FSH, LH, and progesterone levels are low

degradation of the corpus luteum

In menses phase, progesterone levels decline as a result of _______

Proliferative Phase 1st Step

Endometrium begins to proliferate

Proliferative Phase 2nd Step

the rising estrogen concentrations stimulate the endometrial lining to rebuild

Proliferative Phase 3rd Step

high estrogen concentrations will eventually lead to a decrease in FSH as a result of negative feedback

will also stimulate the LH surge that will trigger ovulation

Proliferative Phase 4th Step

ovulation marks the end of the proliferative phase as well as the end of the follicular phase

Day 14

What day does ovulation occur on a typical 28-day menstrual cycle?

High estrogen levels cause (secretory phase)

Prompt the LH surge

result in uterine tube contractions that facilitate the pick-up and transfer of the ovulated oocyte

slightly decrease the acidity of the vagina, making it more hospitable to sperm

Luteal Phase (Secretory Phase)

in the ovary, the corpus luteum is formed

progesterone prepares the endometrium for implantation

glycogen

In secretory phase, over the next 10 to 12 days, the endometrial glands secrete a fluid rich in ______

If fertilization has occurred (Secretory Phase)

the fluid from the glands will nourish the zygote

arteries develop to provide blood to the thickened stratum functionalis

If fertilization does not occur within 10-12 days

corpus luteum ——> corpus albicans

levels of both estrogen and progesterone will fall, and the endometrium will grow thinned

prostaglandins will be secreted that cause constriction of the spiral arteries, reducing oxygen supply

the endometrial tissue will die, resulting in menses (first day of cycle)

estrogen; progesterone

Both ________ and _______ contribute to breast development

Menopause

time when female’s menstrual cycles cease, typically between 45 and 55

women can no longer conceive after this

PAP test; 21-25; 3 years

Women should receive a ________ beginning at age _____ for average risk every ______

PAP Smear

cells are removed from cervix and checked for abnormalities

doctor also checks for abnormalities with uterus and the bladder

Factors that sperm may be hindered by (fertilization)

acidity of the vagina

thick cervical mucus of the uterus

phagocytic uterine leukocytes

The Journey (Fertilization)

________ facilitated by uterine contractions

______ takes from 30 minutes to 2 hours

3-5 days

if the sperm does not encounter an oocyte immediately, they can survive in uterine tubes for another ______

before ovulation

Fertilization can still occur if intercourse takes place a few days ___________

24 hours; does not result on fertilization

Because an oocyte can survive independently for only _____ following ovulation, intercourse more than a day after ovulation usually _______

Capacitation (priming)

fluids improve the motility of the spermatozoa and deplete cholesterol molecules embedded in the membrane of the head of the sperm

this thins the membrane and releases lysosomal enzymes needed for the sperm to penetrate the oocyte’s exterior

if the sperm reaches the oocyte before this is complete, they will be unable to penetrate the oocyte’s thick outer layer of cells

Zygote

first cell after fertilization

Fertilization 1st Step

Egg and sperm will fuse to form the zygote

Fertilization 2nd Step

Corona radiata and zona pellucida on egg provide protection and nutrients to the cell

Fertilization 3rd Step

acrosome of sperm will have enzymes needed to fuse with and bind to zona pellucida and trigger reactions

Fertilization 4th Step

once both plasma membranes have fused the sperm nucleus will be transferred into the egg making it diploid

Fertilization 5th Step

proteins will then be released from the egg preventing another sperm from fusing