XII Chap 3 Human Reproduction Flashcards
What are the 6 reproductive events in humans?
- Gametogenesis
- Insemination
- Fertilisation
- Implantation
- Gestation
- Parturition
Both male and female reproductive systems are in the pelvic regions. T or F?
True
What are the components of the male reproductive system?
- Testes (pair)
- Accessory Ducts
- Accessory Glands
- External genitalia
Scrotum?
Pouch outside abdominal cavity;
contains testes;
maintains low temperature to allow for spermatogenesis
What temperature does the scrotum maintain?
2-2.5° C lower than internal body temp
Shape + Dimensions of Testis?
Covering?
Compartments?
In adults - oval, 4-5 cm long, 2-3 cm wide
Has a dense covering
Has 250 compartments called testicular lobules
What are testicular lobules?
compartments inside the testis in which sperm are produced
How many testicular lobules in male body?
250 * 2 (since pair of testis)
How many testicular lobules in a testis?
250
Seminiferous tubules?
Inside a testicular lobule (3 per lobule) in which sperms are produced;
highly coiled structures
What are the 2 types of cells in seminiferous tubules and their functions?
- Spermatogonia (male germ cell) - produce sperms by meiotic division
- Sertoli cell - provide nutrition to the germ cells
What are interstitial cells?
Regions outside seminiferous tubules;
contain small blood vessels;
secrete androgens
Interstitial cells are another name for Sertoli cells. True or False?
False. Leydig cells = Interstitial cells = outside seminiferous tubules
Sertoli cells = nutrition for germ cell inside tubule
Name the male accessory ducts
- Rete testis
- Vasa efferentia
- Epididymis
- Vas deferans
Describe the path a sperm would take through the male reproductive system
Produced in seminiferous tubules -> rete testis -> vasa efferentia -> epididymis -> vas deferans, which ascends over abdomen loops over urinary bladder -> duct from seminal vesicle -> ejaculatory duct in urethra
Where does the urethra originate from and terminate in males?
Urinary bladder, extends through penis, terminates in external opening (urethral meatus)
What is the external male genitalia called?
Penis
What is the penis made up of?
Special tissue for erection and insemination
What is the glans penis?
Enlarged end of the penis
Foreskin?
Covering on glans penis
Name the male accessory glands
- Paired seminal vesicles
- Prostate
- Paired Bulbourentral glands
What role do the male accessory glands play?
Seminal vesicles, prostate and bulbourenthral secrete “seminal plasma” which contain fructose, calcium and enzymes
Bulbourenthral gland also helps lubricate penis
What are the components of the female reproductive system?
- Pair of ovaries
- Pair of oviducts
- Uterus
- Vagina
- Cervix
- External genitalia
What are ovaries?
Primary female sex organ; produce ovum (gamete) and steroid (ovarian) hormones; one on each side of lower abdomen
Describe the morphological attributes of ovaries
2-4 cm in length;
connected to pelvic wall and uterus via ligaments;
thin epithelium covering that encloses ovarian stroma (binding connective tissue)
What are the 2 zones in the ovarian stroma?
Peripheral cortex
Inner medulla
What’s another name for fallopian tube?
Oviducts
Fallopian tubes are usually _________ in length
10-12 cm
Fallopian tube extends from the ______ to the ______
Periphery of EACH ovary to the uterus
3 parts of the oviduct?
- Infundibulum - closer to the ovary, funnel-shaped
- Ampulla - wider part
- Isthmus - narrow lumen, joins uterus
What are fimbriae?
Finger-like projections;
At edges of the infundibulum;
Responsible for ovum collection at end of ovulation
Another name for uterus
Womb
Uterus is always single. T or F?
True
What are perimetrium, myometrium and endometrium?
3 layers of tissue in the uterine wall
Uterus is attached via ligaments to the ________
pelvic wall
Shape of uterus?
Inverted pear
What is the perimetrium?
Thin, membranous, external
What is the myometrium?
Thick, smooth, middle;
responsible for contractions during delivery
What is the endometrium?
Glandular, inner (lines the uterine cavity);
cyclical changes in menstrual cycle
What is the cervix?
Lower part of the uterus that opens into the vagina
The cavity in the cervix is called the birth canal. T or F?
False, it’s called the cervical canal.
Birth canal includes vagina.
Birth canal?
Cervical canal + vagina
What are the female genitalia?
- Mons pubis
- Labia majora
- Labia minora
- Hymen
- Clitoris
What is the mons pubis?
Fatty tissue with skin and pubic hair
Differentiate between labia majora and minora
Majora - fleshy folds of tissue, extending from mons pubis down to and surrounding the vaginal opening
Minora - paired folds of tissue under the majora
What is the hymen?
membrane partially covering the vaginal opening, may or may not be torn in first coitus
What is coitus?
Sexual intercourse
Clitoris?
Tiny, finger-like structure at upper junction of the 2 labia minora, above urethral opening
Only some female mammals have mammary glands. T or F?
False, all do
What are the mammary glands?
Paired structures (breasts) that contain glandular tissue and fat
All females have the same amount of fat in their mammary glands. T or F?
False, variable amounts
__________ is divided into mammary lobes. How many?
Glandular tissue of each breast;
15-20 mammary lobes
How many mammary lobes in each female mammal?
30-40 (two breasts)
What are alveoli?
Clusters of cells that make up mammary lobes;
secrete milk stored in their cavities (lumens)
How does milk travel in the mammary gland?
Lumens (cavities) of alveoli –> mammary tubules ==> mammary ducts ==> mammary ampulla –> a lactiferous duct –> milk is sucked out
Female reproductive system + mammary glands are separate in structure and function. T or F?
False, they are integrated
What processes do the female reproductive system and mammary glands together support?
Ovulation; Fertilisation; Pregnancy; Birth; Childcare
In humans, male gamete is _______ and female gamete is ________
sperm;
ovum
What is the process of gamete production in humans called?
Gametogenesis
Primary male sex organ is ________;
primary female sex organ is _________
Testes;
Ovaries
primary because they produce the gametes
Define spermatogenesis
Immature male germ cells in testis produce sperms
When does spermatogenesis begin?
Puberty
Explain the process of spermatogenesis in detail
Increase in GnRH (hypothalmic hormone);
acts at pituitary gland;
stimulates secretion of LH and FSH;
LH => Leydig cells => androgens => spermatogenesis
spermatogonia (immature germ cells) => mitosis => increase in number => primary spermatocytes (2n) => meiosis I => two secondary spermatocytes (n) => meiosis II => 4 spermatids (n) => spermatozoa (sperms)
What is another name for the spermatogonia?
male germ cell
What is the role of LH and FSH in men?
LH - luteinising hormone - Leydig cells - androgens - spermatogenesis
FSH - follicle stimulating hormone - Sertoli cells - secretions - spermiogenesis
What is spermiogenesis?
Process by which spermatids are transformed into spermatozoa (sperms)
Where are sperms stored after spermatogenesis and how are they released?
Sperm heads become embedded in the Sertoli cells => released by spermiation
What are the ploidy of the following? Spermatogonia Primary spermatocytes Secondary spermatocytes Spermatids Spermatozoa
Spermatogonia - 2n Primary spermatocytes - 2n Secondary spermatocytes - n Spermatids - n Spermatozoa - n
Name the 4 main parts of the sperm
Head, neck, middle & tail
Sperm head has a plasma membrane that covers it. T or F?
False, plasma membrane envelopes the entire sperm body, not just head
Describe the head of the sperm
Nucleus - elongated, haploid
Acrosome - cap-like cover for anterior portion of nucleus, enzymes to fertilize ovum
Describe the middle of the sperm
Middle - contains mitochondria that provide energy for movement of tail (motility)
How many sperms are ejaculated during coitus?
200-300 million
What are the characteristics of sperm in a normal, fertile man?
60% of sperms are of normal shape & size
40% show vigorous mobility
Sperms are released from _________ and transported by ____________
seminiferous tubules;
accessory ducts
Secretions of epididymus, vas deferans, seminal vesicle & prostrate help in ______ and ______ of sperms
maturation and motility
What is semen?
Seminal plasma + sperms
Functions of the male sex accessory ducts and glands are maintained by ________
androgens (testicular hormones)
What is the formation of female gametes called?
Oogenesis
When does oogenesis and spermatogenesis begin?
Oogenesis - in embryo (fetal stage)
Spermatogenesis - at puberty
What is oogonia?
Gamete mother cells formed in the fetal ovary
How many oogonia does a female have?
Couple million formed in fetal ovary; no more formed/added after birth
Explain the process of oogenesis in detail
Initiated in embryonic stage;
couple million oogonia formed in fetal ovary => prophase-I of meiotic % and temporary arrest => primary oocytes;
Each primary oocyte gets granulosa cell layer => primary follicle => one more layer + new theca => secondary follicle => one more layer => tertiary follicle => mature/Graafian follicle
Primary oocyte grows => meiosis => secondary oocyte + first polar body
Secondary oocyte gets “zona pellucida” membrane
Graafian follicle ruptures, releasing secondary oocyte (ovum)
Oogonia until a female hits puberty. True or False?
False; stop after birth
Primary oocytes degenerate from birth onwards, so that there are ________ in each ovary by puberty
60-80k
Tertiary follicle has a special feature?
Fluid-filled cavity called antrum
How is the theca layer in the tertiary follicle organized?
outer theca externa
inner theca interna
Secondary oocyte retains which key feature of the primary oocyte?
Nutrient rich cytoplasm
Does the first polar body born out of first meiotic division divide further or degenerate?
We don’t know at present
What is the zona pellucida?
The new membrane of the secondary oocyte that’s formed before it gets expelled from the Graafian follicle; sperm induces changes in this membrane when entering so no other sperm can fertilize the same ovum
What becomes the ovum?
Primary oocyte Primary follicle Secondary oocyte Secondary follicle First polar body Graafian follicle
Secondary oocyte
What is menstruation?
Reproductive cycle in female primates if ovum is not fertilised; repeated every 28/29 days
When does the menstrual cycle cease?
If egg is fertilized or menopause
What is the first menstrual cycle called?
Menarche
Describe the menstrual cycle in detail
- Menses - endometrium breakdown - 3-5 days
- Follicular phase - primary to Graafian follicle - endometrium proliferates - LH, FSH and estrogen increase
- Ovulatory phase - LH surge => Graafian follicle ruptures => release of ovum;
- Luteal phase - corpus luteum => if no fertilization, corpus luteum degenerates => no more progesterone => disintegration of endometrium => new cycle
What are the alternate names for follicular phase? luteal phase?
follicular = proliferative phase luteal = secretory
What is LH surge?
LH and FSH at peak on day 14
Name the 2 ovarian hormones
Estrogen and Progesterone
Name the 2 pituitary hormones
FSH & LH
How many ovums released per menstrual cycle?
ONE
Changes in what hormones induce changes in ovary and uterus in menstrual cycle?
Estrogen, Progesterone, FSH and LH
LH and FSH are __________
gonadotropins
What is the term for when the endometrium regenerates?
Proliferation
What causes blood flow in the menstrual phase?
Breakdown of endometrium and its blood vessels
What are all the phases in menstrual cycle?
Menses / Menstrual phase
Follicular / Proliferative phase
Ovulation / Ovulatory phase
Luteal / Secretory phase
Define corpus luteum
Remains of the Graafian follicle after it ruptures, source of progesterone
LH and FSH stimulate ____ which stimulates _____
follicular development which stimulates estrogen secretion
Ovulation occurs in the middle of the menstrual cycle. True or False?
True
Menopause in humans occurs at age _____
50
What is fertilization and where does it take place?
Fusion of sperm with ovum; ampullary region
What is insemination?
When semen is released from the penis and into the vagina
What is the trajectory of the sperm in the female reprod system?
Swim through the cervix -> uterus -> ampullary region where fertilization occurs
Why does not all coitus lead to pregnancy?
Fertilisation can only happen if sperm and ovum are transported to the ampullary simultaneously
Describe in detail what occurs during fertilization?
Coitus => insemination (semen released from penis to vagina) => sperms swim through cervix to uterus to ampullary region
Sperm enters the zona pellucida layer of the ovum -> changes the membrane to block other sperm
Acrosome secretion helps the sperm enter
Sperm -> plasma membrane -> cytoplasm
Secondary oocyte -> meitotic division -> haploid ovum (ootid) and second polar body
Ootid + sperm fuse to produce a diploid zygote
What is an ootid?
Haploid ovum after secondary oocyte undergoes meitotic division
Chromosomes in male and female
XX - female
XY - male
50% of sperms carry X chromosome and 50% carry Y chromosome => there’s always a 50% chance in a pregnancy that the child is a girl or a boy. True or False?
True
What is cleavage?
Mitotic division as zygote moves through isthmus & oviduct towards uterus;
2 -> 4 -> 6 -> 8 daughter cells formed
The daughter cells formed by the zygote during cleavage are called _________
blastomeres
Define blastomeres, morula and blastocysts
Daughter cells (2-16) are called blastomeres
Morula: embryo with 8-16 blastomeres
Blastocysts: After morula divides sufficiently (has outer and inner layer, trophoblast + inner cell mass)
What are the components of a blastocyst?
Trophoblast - outer layer - gets attached to endometrium
Inner cell mass –> differentiates as embryo
How does implantation occur?
Trophoblast layer gets attached to endometrium;
Inner cell mass differentiates into embryo;
After attachment, uterine cells divide rapidly and cover the blastocyst => blastocyst gets embedded => implantation
What happens after implantation?
Chorionic villi (on trophoblast) and uterine becoming interdigitated to form placenta
What is placenta
structural and functional unit between embryo and maternal body connecting them by umbilical cord;
supplies oxygen, nutrients;
removes CO2 and waste
What are chorionic villi
finger-like projections on trophoblast,
appear after implantation - at which time surrounded by uterine tissue and maternal blood
Placenta releases hormones => acts as ___________ tissue
Endocrine
Hormones produced by placenta?
hCG (Human chorionic gonadotropin)
hPL (human placental lactogen)
estrogens
progestogens
What hormones are released during pregnancy?
hCG hPL estrogens progestogens relaxin cortisol thyroxine prolactin
hCG and hPL are produced only during menstruation and pregnancy. True or False?
False, only during pregnancy
Relaxin is produced only during early pregnancy. True or False
False, only in later stages of pregnancy
How does embryo differentiate after implantation?
Ectoderm, endoderm first
Later mesoderm comes in the middle of those two
What produces all the tissues (organs) in adults?
Ectoderm, mesoderm, endoderm
Inner cell in embryo contains _____ cells that produce all tissues and organs
Stem
Key features of 1 month of pregnancy?
Heart forms
Key features of 2 months of pregnancy?
limbs and digits form
Key features of 1st trimester of pregnancy?
most organ systems formed;
limbs, external genitals formed
Key features of 5 months of pregnancy?
first movements; hair on head
Key features of 2nd trimester of pregnancy?
fine hair on body, eyelids separate, eye lashes form
What is common name for gestation period?
Pregnancy
What is scientific name for delivery?
Parturition
What is parturition?
Expulsion of baby through birth canal
How is parturition induced?
Complex neuroendocrine mechanism involving cortisol, estrogen and oxytocin
Starts with foetal ejection reflux (mild contractions);
Contractions and oxytocin increase each other until baby expelled
What is foetal ejection reflux?
Mild uterine contractions at beginning of parturition
What is expelled first? Placenta or baby?
Baby, then placenta
Mammary glands differentiate after pregnancy to produce milk. T or F?
F, differentiate during pregnancy
What is lactation?
Production of milk by mammary glands
What is colostrum?
Milk of the initial day; high in antibodies to build resistance in newborn baby
Differentiate between spermatogonia spermatogonium spermatogenesis spermiogensis spermatozoa sperm spermatid spermatocytes spermiation
spermatogonia - male germ cells
spermatogonium - singular, one male germ cell
spermatogenesis - process by which sperms are produced
spermiogenesis - process by which spermatids become sperms
spermatozoa - sperms
sperms - male gamete
spermatid - step before sperm, formed by secondary spermatocytes
spermatocytes - some of the spermatogonia that undergo meiosis
spermiation - when sperm heads are released from Sertoli cells in seminiferous tubules
Which are parts of male/female reproductive organs that come in pairs?
testes / ovaries
seminal vesicles, bulbourethral glands
oviducts (aka fallopian tubes)
mammary glands
Primary oocyte completes its first meiotic division within:
primary follicle - secondary follicle - tertiary follicle - Graafian follicle
tertiary follicle
Structure of a testis of mammal can be identified by the presence of:
spermatogonia - spermatocytes - Sertoli cells - spermatids
Sertoli cells
Graafian follicle secretes which hormone:
cortisone - relaxin - progesterone - none of the above
progesterone
How many sperms are produced by a secondary spermatocyte?
2
each secondary spermatocyte produces 2 => 4 in total
Hormones for the menstrual cycle are produced by ______
ovary and anterior pituitary
What is the correct hormonal sequence in the case of menstruation? estrogen > FSH > progesterone estrogen > progesterone > FSH FSH > progesterone > estrogen FSH > estrogen > progesterone
FSH > estrogen > progesterone
Epididymis is located in the _____ of the testis:
a) anterior surface
b) lateral surface
c) posterior surface
d) anterolateral surface
posterior surface
Which of these is correct? Ovary is not
a) covered by thick epithelium to enclose stroma
b) having stroma with outer part cortex and inner medulla
c) 2-4 cm in length
d) secreting several steroidal hormones
a) covered by thick epithelium to enclose stroma
- it’s covered by a THIN epithelium that encloses stroma
Clitoris is located at
a. upper junction of two labia minora
b. upper junction of two labia majora
c. below the urethral opening
d. more than one option is correct
a. upper junction of two labia minora
Mammary lobe does not have:
a. alveoli
b. lumens
c. mammary tubules
d. lactiferous duct
d. lactiferous duct
Secretions of _______ seminal vesicle and prostate are essential for maturation and motility of sperm
a. epididymis
b. vas deferans
c. both
c. none
c. both
Widest peak during standard menstrual cycle is observed for:
FSH - LH - estrogen - progesterone
progesterone
Sex of the baby is determined at:
insemination - zygote formation - implantation - gestation
zygote formation
Parturition is induced by:
neural mechanism - endocrine mechanism - both of above - local mechanism
both of above
Oxytocin acts on:
foetus - placenta - uterine muscles - more than one option
uterine muscles