The Reproductive Systems Flashcards
Designed to provide for the continuation of life
Process by which genetic information is passed from generation to generation
The Reproductive Systems
Sexual reproduction involves the process of _________ – form male and female gametes
Gametogenesis
Primary sex organs (gonads) produce:
Gametes and sex hormones
Accessory structures include:
Ducts, glands and external genitalia
Primary sex organ – testes
Accessory ducts – epididymus, ductus (vas) deferens, ejaculatory duct, urethra
Accessory glands – seminal vesicles, prostate gland, bulbourethral glands
Male Reproductive System
Male reproductive system:
Primary sex organ –
Testes
Male reproductive system:
Accessory ducts –
Epididymus, ductus (vas) deferens, ejaculatory duct, urethra
Male reproductive system:
Accessory glands –
Seminal vesicles, prostate gland, bulbourethral glands
Paired oval glands (5 cm long, 2.5 cm diameter)
located in scrotum: pouch of skin and subcutaneous tissue outside abdominal cavity
Testes
Cooler temperature in scrotum by at least 3 degrees below body temp. (~ 34°C) is needed to produce viable _______
Sperm
Testes involves ______ and _______ muscles of scrotum
Dartos; cremaster
Fibrous capsule surrounding the testes that divides the testes into > 250 lobules
Tunica albuginea
Each lobule contains 1-4 highly coiled seminiferous tubules where ______ are produced
Sperm
Are 2 types of cells in seminiferous tubules:
Spermatogenic cells
Sertoli (sustentacular) cells
Give rise to sperm
Spermatogenic cells
Nourish, protect and support spermatogenic cells
Sertoli (sustentacular) cells
Between tubules are Leydig (interstitial) cells which produce
Testosterone
Large cells that extend from the basement membrane of tubule to lumen
Tight junctions join Sertoli cells
Form blood – testis barrier
Sertoli (Sustentacular) Cells
Substances from blood must pass thru Sertoli cells before they reach developing
Sperm
Sertoli (Sustentacular) Cells prevents an immune response against ________ cell’s surface antigens which are “foreign” to immune system (as immune system develops before puberty)
Spermatogenic
Nourish spermatocytes, spermatids + sperm Phagocytize excess spermatid cytoplasm Control movements of spermatogenic cells Control release of sperm into lumen Produce fluid for sperm transport Regulate effects of FSH and testosterone
Function of Sertoli cells
Sertoli cells secrete hormone – inhibin which:
Inhibits FSH release
Sertoli cells secrete ________ – binding protein into lumen → binds testosterone therefore keep it high for final stages of spermatogenesis
Androgen
Occurs in seminiferous tubules
Takes about 64-72 days
Starts from outer wall of tubule towards lumen
Spermatogenesis
Spermatogonia (stem cells that are 2N and remain dormant until puberty) divide by mitosis giving rise to:
Type A and B spermatogonia
Remain at basement membrane as a reservoir of cells for future cell division
Type A cells
Grow and move toward lumen, called primary spermatocytes
Type B cells
Spermatids are small, round cells close to lumen and undergo spermiogenesis to become _________ – shed cytoplasm
Spermatozoa
Spermatozoa has 3 parts:
- head
- midpiece
- tail
Has nucleus and acrosome
Head
Contains mitochondria
Midpiece
Is a flagellum
Tail
Sperm are released into lumen of:
Seminiferous tubule
At puberty, hypothalamus increases secretion of gonadotropin-releasing hormone
Stimulates anterior pituitary to release LH and FSH
Hormone control of Testes
FSH (follicle stimulating hormone) stimulates _____ cells to release androgen binding protein
Sertoli
LH (luteinizing hormone) stimulates _____ cells to release testosterone
Leydig
Combined effect (LH and FSH) is to stimulate:
Spermatogenesis
Testosterone also promotes development of male _________ sex characteristics
Secondary
Stimulates male development of reproductive systems ducts + descent of testis; development of external genitalia
Testosterone before birth
Enlargement of male sex organs + development of secondary sex characteristics (facial/chest hair, enlarged larynx for deep voice, bones/muscles ↑ in size and mass)
Testosterone at puberty
A hormone released by the Sertoli cells which suppresses the production of FSH once spermatogenesis has progressed
Inhibin
From _________ tubules (#1), sperm enter straight tubules (#2)
Seminiferous
Next, enter network of ducts, ____ testis (#3)
Rete testis
To move into coiled efferent ducts in the _______ (#4)
Epididymis
_______ (#5) lies on surface of testes
- takes about 20 days to travel
- storage and maturation site of sperm
Epididymis
Are expelled during ______ into ductus (vas) deferens (#6)
- spermatic cord consists of the ductus deferens, blood vessels and nerves
Ejaculation
_______ joins with the duct of the seminal vesicle to form the short ejaculatory duct (#7)
Ampulla
Ejaculatory duct enters ______ gland and empties into urethra (#8)
Prostate
Extends from bladder to tip of penis
Urethra
Muscular tube that passes into pelvic cavity
- ends behind urinary bladder
- enlarges to form ampulla
Ductus deferens
Contains 3 cylindrical masses of erectile tissue: blood sinuses lined by endothelial cells surrounded by smooth muscle and elastic CT
Penis
Two lateral masses
Corpora cavernosa
Midventral mass containing the spongy urethra
Corpus spongiosum
= enlargement and stiffening of penis
Erection
= sympathetic reflex
- close urethra at base of bladder
Ejaculation
Accessory glands of the Penis produce seminal fluid and include:
- Seminal Vesicles (2)
- Prostate Gland (1)
- Bulbourethral Glands (2)
Produce viscous alkaline fluid
Adds ~ 60% of seminal fluid
Released into ejaculatory ducts
Seminal Vesicles (2)
Surrounds urethra below bladder
Adds ~ 35% of seminal fluid
Slightly acidic secretion
Empties into prostatic urethra
Prostate Gland (1)
Produce thick clear mucus prior to ejaculation
Alkaline secretion
Lubricates end of penis and lining of urethra
About 5% of fluid volume
Released into urethra
Bulbourethral Glands (2)
- mixture of sperm and seminal fluid
- about 2-5 ml released per ejaculation
- contains about 100 million sperm/ml (if # below 20 million sperm/ml considered infertile)
- pH is 7.2-7.7
Semen
Semen functions to provide sperm with a:
Transport medium
Semen functions to provide sperm with ________
Nutrients
Semen functions to ________ ______ of male urethra and female vagina
Neutralize acidity
Semen contains an _______ to destroy bacteria in semen and lower female reproductive tract
Antibiotic
Primary sex organ – ovaries
Accessory ducts – uterine tubes (oviducts), uterus, vagina
Female Reproductive System
Female Reproductive System primary sex organ:
Ovaries
Female Reproductive System accessory ducts:
Uterine tubes (oviducts), uterus, vagina
Paired almond-shaped organ, held in place by broad, ovarian and suspensory ligaments
Surrounded by tunica albuginea covered by germinal epithelium
Ovaries
Ovary has:
Cortex and medulla
Outer cortex contains:
Ovarian follicles
Inner medulla contains:
Loose CT, blood vessels, lymph vessels and nerves
Oogenesis begins:
BEFORE BIRTH!!
Occurs in ovarian follicles in cortex of ovary
Takes years to complete
Oogenesis
Oogonia (2N) are formed when the female is a:
Fetus
Divide by mitosis to form primary oocytes (2N)
Oogonia (2N)
Primary oocytes (2N) are arrested in prophase I of meiosis until:
Puberty
Is surrounded by a layer of follicle cells and is called a primordial follicle
Primary oocytes (2N)
At puberty, secretion of FSH results in primordial follicle becoming a:
Primary follicle
Follicle cells grow and become:
Granulosa cells
Granulosa cells produce:
Estrogen
Fluid-filled cavity (antrum) forms and becomes a _________ follicle
Secondary follicle
Primary oocyte completes meiosis I and gives rise to a large secondary oocyte (n) and first polar body
- becomes a mature ______ follicle that is ovulated
Graafian
Graafian follicle migrates to:
Ovary surface
LH triggers _______ and follicle ruptures
Ovulation
Secondary oocyte is released into pelvic cavity and swept into:
Oviduct
FERTILIZATION TAKES PLACE IN THE:
OVIDUCT!!
Secondary oocyte will only complete meiosis II if:
Fertilization occurs
Produces large ovum and second polar body
Secondary oocyte
Nuclei of sperm cell and ovum unite to form a diploid ______ that begins to undergo cell divisions
Zygote
Remainder of ruptured follicle becomes ______ _____ within ovary which will secrete progesterone and estrogen
Corpus luteum
If fertilization does not occur, corpus luteum degenerates as LH levels decrease (becomes corpus ________)
Albicans
Once corpus luteum degenerates, hormones decrease and FSH and LH:
Restart cycle
Pathway of oocyte:
Secondary oocyte is drawn into funnel-shaped infundibulum of oviduct by action of:
Fimbriae
Takes 4 days to travel oviduct, helped by cilia and _______
Peristalsis
FERTILIZATION OCCURS IN THE:
OVIDUCT
Unless fertilized within first ____ hours after ovulation oocyte degenerates
24
A fertilized egg arrives at the uterus ____ days after ovulation
6-7
Uterus is composed of 3 sections:
Fundus, body, cervix
Receives fertilized ovum
Protects and nourishes embryo
Uterus
Uterus wall has 3 layers:
- outer perimetrium
- thick middle myometrium of 3 layers of smooth muscle
- inner endometrium
Part of visceral peritoneum
Outer perimetrium
Thick middle, 3 layers of smooth muscle
Myometrium
Composed of superficial Functional layer and a deeper Basal layer
Inner endometrium
Highly vascularized
Contains numerous uterine glands (invaginations of epithelium) that secrete nutritious glycogen into uterine cavity to sustain embryo until it implants
Inner endometrium
Inner endometrium is divided into 2 layers:
1) Functional layer
2) Basal layer
Sloughs off during menstruation
Functional layer
Permanent layer that gives rise to a new functional layer after menstruation
Basal layer
Extends from cervix to external genitalia
Vagina
Passageway for infant, discharge of menstrual fluid and receives semen
Lined with non-keratinized stratified squamous epithelium for protection from abrasion
Contains stores of glycogen – produces organic acids (acidic pH)
Vagina
Cervix mucosal cells produce:
Mucus
At ovulation, cervix mucus is less:
Viscous
Cervix mucus can block cervical canal when not _______ (impedes sperm)
Fertile
Blocks spread of bacteria (vagina → uterus)
Cervix mucus
Cyclical changes occur in the ovaries and uterus under the control of hormones secreted by the:
Hypothalamus, anterior pituitary and ovaries
Events involved in maturation of an oocyte
Ovarian cycle
Events that prepare uterine endometrium to receive a fertilized ovum
Menstrual (Uterine) cycle
Cycle is about ___ days
28
Ovarian cycle is composed of 2 phases:
- Follicular Phase
2. Luteal Phase
Ovarian cycle: days 1-14 (can vary from female to female)
Follicular Phase
Period of follicle growth
Hypothalamus secretes GnRH which causes anterior pituitary to release FSH and LH
Follicular Phase
FSH and LH stimulate follicle ______ and maturation
Growth
Follicle cells produce ________ which results in an increase in LH released
Estrogens
Ovulation occurs on day ___ (mid cycle) – triggered when ant. pit. releases surge of LH
14
Graafian follicle _______ and releases secondary oocyte
Ruptures
Days 15-28 (constant length)
- Luteal Phase
Period of corpus luteum activity
Luteal Phase
Corpus luteum forms from ruptured follicle and secretes:
Progesterone and estrogens
High levels of estrogen and progesterone inhibit release of ___ and ____ from anterior pituitary
LH; FSH
If secondary oocyte not fertilized, corpus luteum degenerates about day 24 to Corpus ______
Corpus albicans
As a result, progesterone and estrogen levels ______ and inhibition of anterior pituitary ends
Decrease
If secondary oocyte is fertilized, corpus luteum remains active to maintain progesterone and estrogen levels until ______ takes over this function
Placenta
Embryo implants in uterus ~ _ days after fertilization
6
Embryo produces human chorionic gonadotropin (HCG) – stimulates secretory activity of:
Corpus luteum
Presence of ____ in maternal blood or urine is detected as a positive pregnancy test
HCG (Human chorionic gonadotropin)
Menstrual (Uterine) Cycle has 3 phases:
- Menstrual Phase – days 1-5
- Proliferative Phase – days 6-13
- Secretory Phase – days 14-28
Days 1-5
Discharge of menstrual flow
Shed entire functional layer of endometrium
Occurs when ovarian hormones are low
Menstrual Phase
Days 6-13
As estrogen levels increase from developing follicles, basal layer regenerates a new functional layer
Glands and blood vessels increase in number
Proliferative Phase
Days 14-28
Progesterone and estrogen from the corpus luteum stimulate further development of the endometrium (becomes even more vascular and glandular to prepare for implantation of embryo)
If fertilization does not occur, corpus luteum degenerates which lowers the hormone levels and triggers the menstrual phase to begin again
Secretory Phase
Union of egg + sperm cells
Occurs in uterine tube (oviduct)
Slim “window of opportunity” – 3 days (out of 28)
- from 2 days before ovulation to 1 day after ovulation
- secondary oocyte is viable 24 hours after ovulation
- sperm is viable 48 hours after deposition in vagina
Fertilization
Move up reproductive tract by flagella + contraction of uterus and uterine tube (caused by prostaglandins in semen)
Sperm
When sperm cell contacts ovum, acrosome releases enzyme:
Hyaluronidase
- dissolves part of membrane covering the secondary oocyte
- normally only 1 sperm fertilizes egg, because once it enters, ovum develops a “fertilization membrane” that is impermeable to other sperm
- secondary oocyte completes meiosis II
- divides into larger ovum (mature egg) and smaller second polar body that disintegrates
Hyaluronidase
About age 50, menstrual cycle becomes irregular
Menopause
_______ → cessation of menstrual cycle occurs shortly after
Menopause
Menopause results from failure of ovaries to respond to stimulation of LH + FSH from ant. pituitary therefore, no ________
Ovulation
Some atrophy (degeneration) of ovaries, uterus, uterine tubes, vagina, external genitalia + breasts (due to low ________)
Estrogen
May experience sweating, fatigue, anxiety, headaches, muscular pain
Menopause
The _______ muscle is the skeletal muscle at the scrotum.
Cremaster
The corpus luteum will secrete:
Estrogen
Which cells produce testosterone?
Leydig cells
The myometrium is made of:
Smooth muscle
Final maturation of sperm cells occurs in the:
Epididymus
Transport medium for sperm
Provide sperm with nutrients
Neutralizes acidity of male urethra and female vagina
Contains antibiotic to destroy bacteria
Function of semen
The structure that surrounds the urethra (males) just below the bladder is the:
Prostate gland
Which hormone triggers ovulation?
Luteinizing Hormone
During spermatogenesis, which cell type undergoes meiosis I to produce a haploid cell?
Primary spermatocyte
Smooth muscle in scrotum: if cold, muscle contracts & scrotal skin will contract to reduce heat loss
If too hot, muscle relaxes, scrotal skin is loose to promote heat loss
Dartos muscle
Sperm cell from most immature to most mature:
Spermatogonium Primary Spermatocyte Secondary Spermatocyte Spermatids Spermatozoa
First incidence where sperm cell is haploid:
Secondary spermatocyte
Sperm require full mobility in epididymis and can be stored here ___-___ days, if not ejaculated then body reabsorbs them
40-60
Seminal fluid contains ________ and ____________
Fructose; clotting proteins
Energy for sperm
Fructose
Help semen coagulate after ejaculation
Clotting proteins
Attaches to the ovaries by mesovarium (double layered fold of peritoneum)
Broad ligament
Anchor ovaries to uterus
Ovarian ligament
Attach ovaries to pelvic wall
Suspensory ligaments
At puberty ~40,000 oocyte (2N) remain, the rest have already __________
Degenerated
Ovarian cycle and menstrual cycle:
Happen at the same time
Promotes growth & development of female reproductive organs at puberty, responsible for secondary sex characteristics - breast growth, wide hips, etc.
Estrogen
