Reproductive and Urinary Systems

How are the reproductive systems divided?

into make and female systems

What does each reproductive system have?

gonads and accessory reproductive organs

What are gonads?

primary sex organs responsible for producing gametes (eggs and sperm) and secreting sex hormones (testes and ovaries)

What are accessory reproductive organs?

structures used to transport and nourish gametes prior to fertilization

Where are sperm formed?

sperm are formed in the testes. each testis has many tightly coiled seminiferous tubules where sperm are produced

Where do sperm go after production?

after production, sperm are transported into the rete testis and then to the epididymis

What is the epididymis?

the epididymis is a highly coiled tube (6 meters long). the sperm mature during the 20 days it takes to travel through the epididymis before reaching the ductus deferens (vas deferens)

Where are sperm stored?

sperm are stored in the enlarged ampulla of the ductus deferens

What happens when a man is sexually stimulated?

sperm are expelled into the ejaculatory duct and out through the urethra in a process called ejaculation

What are the three major glands associated with the male reproductive system?

seminal vesicles, prostate gland, and bulbourethral glands (Cowper's glands)

What do the accessory glands do?

they produce secretions that form semen, which dilutes the sperm and protects them as they travel

What do the seminal vesicles do?

nutrition, mobility through muscular contraction, clotting of ejaculate

What does the prostate gland do?

thins semen for easier sperm movement and citric acid for energy

What do the bulbourethral glands (Cowper's glands) do?

alkaline mucus to neutralize the urethra and lubricate the penis

What are the two major external structures of the male reproductive system?

the scrotum and penis

What is the scrotum?

it is a flap of skin between the legs that contains the testes. the scrotum maintains an ideal temperature for sperm survival, which is 2-3 degrees Celsius lower than normal body temperature

What are the cremaster muscles?

they control how near the testes are to the body based on external temperature

What is the penis?

the structure that delivers sperm into the female reproductive tract

What is the penis composed of?

shaft, glans penis (tip), and erectile tissue (spongy internal tissue that fills with blood during sexual excitement causing an erection)

What happens during sexual intercourse?

the erect penis is inserted into the female vagina and the semen is ejaculated, propelling the sperm into the female reproductive tract

What is spermatogenesis?

the process of sperm production

What does spermatogenesis begin with?

stem cells called spermatogonia

What happens during spermatogenesis?

diploid spermatogonia divide through meiosis to create four spermatids with only 23 chromosomes each (half the number of necessary chromosomes)

What is spermiogenesis?

it is the final process of sperm production where the spermatids take the final shape of mature sperm

Where do sperm travel as they develop?

they migrate closer to the lumen of the seminiferous tubules, where they will eventually be released

What are the three parts of sperm?

head, midpiece, tail

What does the head of the sperm do?

the head contains the nucleus and has an acrosome on the front portion, which contains enzyme to break into the egg cell during fertilization

What does the midpiece of the sperm do?

the midpiece is surrounded by mitochondria, giving the sperm ample energy to swim

What does the tail of the sperm do?

the tail (flagellum) provides the movement

What are the primary reproductive organs of the female reproductive system?

the ovaries

What do the ovaries do?

the ovaries release egg cells (ova) to be fertilized by sperm. the ovaries contain about 400,000 follicles (clusters of cells surrounding an egg) at a female's birth. only about 400 of these follicles will mature and be released as eggs

What is ovulation?

the release of a mature egg

How does an egg travel to the uterus?

the ovaries release the mature ovum into the finger-like fimbriae that extend from the uterine tubes (Fallopian tubes). the ovum is funneled into the infundibulum before entering the tubes. the ovum is carried through the tubes by cilia towards the uterus

What is the uterus?

the uterus is a hollow, muscular structure that recieves and nourishes an egg as it develops into a baby

What are the three portions of the uterus?

the fundus (superior), the body (hollow middle poriton), and the cervix (inferior)

What are the three layers of the uterus?

endometirum, myometrium, perimetrium

What is the endometrium of the uterus?

it is the mucosal layer. if an egg is fertilizsed by sperm in the uterine tubes, the developing embryo will implant in this layer. if the egg is unfertilized, the endometrium will slough off (menstruation)

What is the myometrium of the uterus?

muscular layer responsible for contractions during childbirth

Whst is the perimetrium of the uterus?

the outer uterine wall

What is the vagina?

it is a thin-walled tube located inferior to the cervix. it recieves the penis during intercourse and is the passageway for menstruation and delivery of a baby during childbirth

What does the external female genitalia (vulva) include?

mons pubis (fatty area covered with pubic hair) and labia majora / labia minora (skin folds which protect the area known as the vestibule)

What does the vestibule contain?

clitoris (similar to male penis, swells when stimulated), urethral opening (for urine), vaginal opening, and vestibular glands (lubricate the vagina during intercourse)

What does oogenesis begin with?

stem cells, called oogonia

How do oogonia divide?

before birth, the oogonia divide and develop into primary oocytes, which are housed in follicles

What happens to oocytes at puberty?

hormons stimulate a small number of follicles to mature and make the first meiotic division

What is produced from this meiotic divison?

this division is unequal- a large secondary oocyte and a tiny polar body are produced (the polar body, along with its chromosomes, degenerates)

What happens if the secondary oocyte is fertilized?

the second meiotic division will occur. this produces another polar body and reduces the female chromosome number to 23. the male and female nuclei join to form a zygote with 46 chromosomes

What happens after ovulation?

the follicle degenerates into the corpus luteum

What three hormones do the male reproductive system depend on?

testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH)

What is testosterone?

produced in the interstitial cells of the testes; responsible for maturation of reproductive organs and secondary sex characteristics

What is the luteinizing hormone (LH)?

produced in anterior pituitary gland; stimulates release of testosterone

What is the follicle-stimulating hormone (FSH)?

produced in anterior pituitary gland; stimulates sperm production

What are secondary sex characteristics in males?

increased muscle mass and strength, increased bone mass, facial and pubic hair growth deepening of voice, increased sex drive

What four hormones affect the female reproductive system?

LH, FSH, estrogens, progesterone

What do estrogens do?

secreated by the ovaries; causes female secondary sex characteristics

What does progesterone do?

produced by corpus luteum after ovulation; helps to maintain the menstrual cycle

What are female secondary sex characteristics?

breast development, pubic hair growth, increased fat deposits on hips and breasts, widening of hips, and onset of menstrual cycle

What is the difference between male and female mammary glands?

both sexes have mammary glands, but estrogens cause female mammary glandsw to increase in size during puberty

What makes up a breast?

within the center of each breast is a darker areola surrounding a nipple. beneath the skin, 15-25 lobes of alveolar glands are connected by connective tissue and fat

What happens during lactation?

when lactating, the alveolar glands produce milk and pass it via the lactiferous ducts through the nipple

What is the uterine (menstrual) cycle?

it involves recurring changes to the endometrium of the uterus due to hormone fluctuations

How long is the menstrual cycle?

on average, the cycle is 28 days long with ovulation occuring on day 14

What are the three stages of the uterine cycle?

menstrutaion (days 1-5), proliferative phase (days 6-14), and secretory phase (days 15-28)

What is menstruation?

endometrium is shed through the vagina (called a period)

What is the proliferative phase?

the follicles in the ovaries grow and produce estrogens, which cause the endometrial lining to thicken again. one of the mature follicles releases an egg

What happens in ovulation?

LH and FSH levels peak, causing the egg to be released from the ovary into the uterine tube

What is the secretory phase?

the corpus luteum secreates progesterone, which causes uterine lining to further thicken. gloands within the endometrium secrete nutrients to sustain an embryo. if the egg is unfertilized, estrogen and progesterone levels decrease, causing the uterine lining to stop thickening

In order for fertilization to occur, when must intercourse occur?

due to the viability of the oocyte and spermatozoa, intercourse must occur five days before ovulation up to one day afterwards

How many sperm cells are chemically attracted to the oocyte?

hundreds of millions of sperm cells are chemically attracted to the oocyte and travel through the uterine tube until they reach it

How many sperm reach the egg?

only a few hundred sperm reach the oocyte. when they do, they all swarm around it simultaneously

What does the acrosome of the sperm do?

the acrosome on the tip of the sperm cells release enzymes that break down the protective layer around the oocyte

What happens when sperm penetrates an egg?

when one sperm penetrates the barrier, the ovum releases granules that coat the outside of the ovum, preventing other sperm from penetrating

What happens after fertiziliation?

the oocyte nucleus completes the second meiotic division, and the chromosomes of the ovum and sperm unite, makin a full diploid set. this fertilized egg is now called a zygote

What are the two major stages in the development of a baby?

embryonic development (fertilization-week 8) and fetal development (week 9-birth)

What is cleavage?

as the embryo moves down the uterine tube, it already begins to divide

How is the embryo when it reaches the uterus?

the embryo is made of 16 cells by the time it reaches the uterus (now known as a morula)

What is a blastocyst?

the stage of embryonic development after the morula divides further to 100 cells. the blastocyst implants itself into the uterine wall 6-7 days after fertilization

What happens during the first two weeks of a blastocyst?

it arranges itself into two layers- an inner cell mass and an outer trophoblast

How does a blastocyte implant into the uterus?

the trophoblast forms projections (chorionic villi) that embed it into the uterus, eventually becoming the placenta

What is the inner cell mass made of?

embryomic stem cells with differentiate into 3 germ layers: ectoderm, mesoderm, and endoderm

What does ectoderm consist of?

neuron and epithelial cells (skin and nervous system)

What does mesoderm consist of?

red blood cell and cardiomyocytes (muscular, reproductive, and cardiovascular systems)

What does endoderm consist of?

liver cells and pancreas cells (respiratory, digestive, urinary, and endocrine systems)

What is an embryo called after 8 weeks?

a fetus

What are some milestones that happen at 12 weeks in fetal development?

fingers and toes are distinct, placenta is complete, fetal circulation is complete, and organ systems are complete

What are some milestones that happen at 16 weeks in fetal development?

sex is differentiated, rudimentary kidneys secrete urine, heartbeat is present, nasal septum and palate close

What are some milestones that happen at 20 weeks in fetal development?

lanugo covers entire body, fetal movements are felt by the mother, heart sounds are perceptible by auscultation

What are some milestones that happen at 24 weeks in fetal development?

skin appears wrinkled, vernix caseosa appears, eyebrows and fingernails develop

What are some milestones that happen at 28 weeks in fetal development?

skin is red, pupillary membrane disappears from eyes, fetus has an excellent chance of survival, eyes open and close

What are some milestones that happen at 32 weeks in fetal development?

fetus is viable, eyelids open, fingerprints are set, vigorous fetal movement occurs

What are some milestones that happen at 36 weeks in fetal development?

face and body have loose wrinkled appearance because of subcutaneous fat deposit, lanugo disappears, amniotic fluid

What are some milestones that happen at 40 weeks in fetal development?

skin ais smooth, eyes are uniformly slate colored, bones of skull are ossified and nearly together at sutures

What happens at 40 weeks of pregnancy?

oxytocin and prostaglandins cause powerful contractions of the uterus through a positive feedback mechanism

What are the three stages of labor?

dilation stage, expulsion stage, placental stage

What happens in the dilation stage?

amniotic sac ruptures (aka water breaking) and cervix becomes thinner and widens, eventually up to 10 cm

What happens in the expulsion stage?

baby is pushed out through the vagina and cervix

What happens in the placental stage?

within 15 minutes after the baby is delivered, the uterus contracts again to expel the placenta (this prevents unnecessary bleeding)

diagram of internal male reproductive anatomy

diagram of internal female reproductive anatomy

diagram of external female reproductive anatomy