What is the purpose of the seminiferous tubules?
1
Produce sperm
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| Term | Definition |
|---|---|
What is the purpose of the seminiferous tubules?
1 | Produce sperm |
What do leydig cells do? what type of cell are they?
2 | - Secrete testosterone
- Interstitial cells |
What do sertoli cells do? what type of cell are they?
2 | - Support sperm development
- Epithelial cells |
What do smooth muscle cells do? what type of cell are they?
2 | - Peristalsis (propel sperm)
- Myoid cells |
What comprises the blood-testis barrier?
3 | - Tight junctions
- Luminal compartment
- Basal compartment |
What does "tropic role" mean? | Support sperm development |
T/F: myoid cells secrete luminal fluid for sperm housing | False, sertoli cells do this |
Sertoli cells: What is the androgen-binding protein?
2 | - Androgen buffer
- Maintain steady conc of Androgen in lumen |
What do sertoli cells do in relation to testosterone and FSH?
2 | - Act as target cells for those hormones
- Secrete paracrine factors which stimulate spermatogenesis |
Sertoli cells: what does inhibin do?
| - Secreted by sertoli cells
- Hormone for negative feedback loop of FSH |
T/F: Sertoli cells phagocytize old sperm | True |
Where is the site of immunosuppression? | Sertoli cells
(Blood testis barrier) |
What are the traits of adolescence?
2 | - Up to age 10-14
- Unable to reproduce |
What are the traits of puberty?
3 | - Usually at age 10-14 (later in boys)
- Sexual maturation (can produce gametes)
- Secondary sexual traits develop |
What are secondary sexual characteristsics?
3 | - Hair
- Voice
- Height |
Can androgens stimulate spermatogenesis? Can they stimulate sex drive? | Yes |
T/F: Androgens do not promote secondary sexual traits? | False, they do |
What is the anabolic effect? | Promote protein synthesis in skeletel muscle |
What stimulates growth hormone secretion? | Androgens |
What are the 3 main phases of spermatogenesis? | - Mitosis: ensures supply of spermatogonia
- Meiosis: half the chromosome number
- Differentiation and packaging: transport genetic material |
Where does spermatogenesis occur?
2 | - From basement membrane to lumen
- Occurs in space between adjacent sertoli cells |
Where does mitochondria occur in sperm? | Midpiece |
What is the sperm head made of?
2 | - Nucleus (chromosomes)
- Acrosome (enzymes for fertilization) |
Where is spermatozoa released into? | Lumen of semineferous tubules |
How does fluid from sertoli cells go to epididymis? | - Pressure from cells |
How does sperm and fluid go to vas deferens? | Peristalsis |
LH vs FSH | LH: androgen secretion
FSH: spermatogenesis |
What are functions of seminal fluid?
3 | - Dilute sperm
- Provide energy (fructose)
- Form semen clot |
What are the accessory glands?
3 | - Seminal vesicles
- Prostate gland
- Bulbourethral glands |
Purpose of seminal vesicles | Secrete alkaline fluid with fructose, enzymes, prostoglandins |
Purpose of prostaglandins | - Secrete citrate and enzymes |
Purpose of bulbourethral glands | Secrete viscous fluid w/ mucus |
T/F: male response controlled by CNS | False, its by ANS |
What are the phases of the male sexual response?
3 | - Erection: parasympathetic
- Emission: sympathetic stimulation to smooth muscles of ducts
- Ejaculation: contraction of skeletal muscle for semen release (somatic control) |
Menarche | Onset of puberty for females |
Menstruation | Female reproductive system cycles |
Menopause | Lose ability to reproduce around 45-50 |
What are the female reproductive organs?
2 | - Gonads (ovaries)
- Reproductive tract (uterus, uterine tuber, vagina) |
T/F: Ovaries are separate from reproductive tract | True |
Purpose of uterine tubes | Transport ova from ovaries to uterus |
Purpose of infundibulum and fimbriae
2 | - Pick up released ovum
- Move/release ovum through uterine tubes |
What is the outer layer of the uterus? | Perimetrium
- Epithelial cells and connective tissue |
What is the middle layer of the uterus? | Myometrium
- Thick
- Smooth muscle |
What is the inner layer of the uterus? | Endometrium
- Layer of epithelial cells
- Layer of connective tissue
- Glands |
What is the cervix? | Canal leading to vagina |
What is the birth canal? | Cervix + vagina |
What is the female gamete? | Egg, or an oocyte |
How many oocytes are in 1 follicle during primary oocyte stage? | One |
What is a primordial follicle? | - Oocyte
- Layer of specialized epithelial cells |
What are granulosa cells? | Layer of epithelial cells divides to become more than 1 layer |
What is folliculogenesis? | - Granulosa cells process through zona pellucida and form gap juntions
- Nutrients/paracrine factors sent through junctions to help oocyte growth |
What is FSH's effect on granulosa cells? and estrogen? | - Stimulate cell multiplication
- Produce estrogen |
What type of receptors do theca cells have? | LH receptors |
What does LH do to theca cells? | Stimulate androgen secretion |
What do androgens do to granulosa cells? What does it lead to for estrogen? | - Permeate to cells and convert to estrogen in granulosa cells
- Estrogen secretion rises and dominant follicle selected |
Functions of granulosa cells
6 | - Secrete antral fluid
- Provide nutrients for oocyte
- Secrete paracrines for follicle
- Secrete inhibin
- Secrete estrogens
- Secrete substances that forms zona pellucida |
What is the pulse generator? | Frequency and amp of pulses change every 24hr of menstrual cycle |
Is number of oogenia for females fixed or continually producing? | Fixed at birth |
When does mitosis start in embryonic life? | In first 2 months |
When does meiosis 1 begin? | In fetal life |
When does meiosis 1 stop? | Through birth until puberty |
When does 1st meiotic division complete in dominant follicle? | Prior to ovulation |
When does meiosis II complete? | After fertilization |
What is the net result of Oogenesis? | 1 primary oocyte produces 1 egg (n) |
What is the net result of spermatogenesis? | 1 primary spermatocyte produces 4 spermatozoa (n) |
Are ovarian hormones required for female differentiation before birth? | No |
What graph do ovarian hormones regulate? | Hypothalamic-pituitary gonadal axis |
What are the components of the hypothalamic-pituitary gonadal axis?
3 | E: Both + and - feedback effects
P: - feedback only
Inhibin: - feedback on FSH |
What do low plasma levels of estrogen cause? When? | Negative feedback early to mid follicular phase |
What do high levels of estrogen cause? | LH surge during late follicular phase |
What happens during the menstrual phase?
4 | - Shed uterine lining
- BF to tissue decreases
- Dead tissue and fall into vagina = flow
- Hormones: due to decreased E/P
Hormones decrease when corpus luteum degenerates |
How does the uterus prepare for fertilized ovum during proliferative phase?
5 | - Endometrial lining develops
- Endometrial layer grows
- Endometrial glands enlarge
- Smooth muscle thickens (myometrium)
- Cervical glands secrete mucus |
What do estrogens do to uterine lining? | Stimulate development of it |
How does the endometrium prepare for implantation during secretory phase?
3 | - Increased blood supply
- Glands enlarge and secrete glycogen-rich fluids
- Cervical secretions more sticky = plug |
What is to product of the fusion of male and female gametes? | Zygote |
How long are the sperm and oocyte viable for fertilization? | Sperm: 5 days
Oocyte: 12-24 hrs |
What does the block to polyspermy do?
4 | - Change membrane potential
- Release contents of cortical granules
- Enzymes enter and harden zona pellucida
- Enzymes inactivate sperm binding receptor |
What does the fusion of sperm to oocyte mean for division? | Stimulates 2nd meiotic division of oocyte
Oocyte -> ovum |
What happens to sperm plasma membrane during fertilization? | Disintegrates |
What happens to DNA during fertilization? | Replicated -> zygote |
What are mitotic divisions called? | Morula |
How do you get identical twins? | Division of totipotent morula cells |
How do you get fraternal twins? | Fertilization of two oocytes (during same cycle) |
What does the outer cell layer of a blastocyst become? what is it called? | - Becomes fetal placenta
- Trophoblast |
What does the inner cell mass of a blastocyst become? | Becomes embryo |
What is the fluid filled cavity of a blastocyst called? | Blastocoele |
T/F: By 5 weeks, the placenta is functioning and heart is beating | True |
Functions of the placenta
3 | - Endocrine organ
- Exchange tissue
- Immunity/filter |
What are the 4 major hormones of pregnancy?
| - hCG: Human chorionic gonadotropic
- hCS: human chorionic somatomammotropin
- Progesterone
- Estrogen |
Purpose of hCG?
1 | Maintain luteum functions in early pregnancy |
Purpose of hCS?
2 | - GH like and anti-insulin actions in mother
- Helps fetus get more glucose |
Purpose of progesterone?
4 | - Decrease contractions
- Inhibit LH and FSH
- Grow mammary alveolar glands
- Secrete sperm unfriendly mucus |
Purpose of estrogen?
3 | - Growth of uterus
- Grow mammary ducts
- Inhibit LH and FSH |
What does the mammary gland look like from birth to puberty? | A few ducts is any alveoli |
What does the mammary gland look like at puberty? | - Ducts grow/branch
- Alveolar growth
- Fat deposit around alveolar tissue |
What does the mammary gland look like during pregnancy and lactation? | - Prolactin
- hPL
- Oxytocin |
What is the purpose of PRL? prolactin | Lactogenesis
- Initiation of milk synthesis
- Low estrogen and progesterone |
What is the purpose of hPL?
| Growth factors |
What is the purpose of oxytocin? | Milk ejection |
What is galactopoiesis? | Maintenance of lactation
- Needs PRL |
What are the three factors to determine the sex of a person? | - Genetic: type of sex chromosome
- Gonadal: Ovaries/testes
- Genitgal/phenotypic: type of internal and external genetalia |
T/F: chromosomal (genetic sex) is determined in 2nd trimester | False, its determined at fertilization |
What dictates differentiation of bipotential gonads to become testes? | Presence of SRY gene on Y chromosome |
What does XY dictate? | Male, testes develop |
What does the presence of more than one X chromo mean? | Impaired spermatogenesis |
What is the chromosomes of someone w/ Klinerfelters syndrome? | XXY Male |
What is Turners syndrome? | Lack of X chromos |
T/F: XXY males are fertile | False |
In males, what do the testes secrete from sertoli cells? | MIH |
What does MIH do? | Cause regression of Mullerian duct and regression of internal female genitalia |
What do testes secrete from Leydig cells? | Testosterone |
What is testosterone converted to? | DHT |
What does DHT do? | Causes masculinization of male genitalia |
In females, what does the absence of MIH do? | Allow mullerian duct to grow into female internal genitalia |
What does the absence of testosterone do? for females | Prevent development of Wolffian duct = no male internal genitalia |
Sexual disorders: Female XX but outwardly male | Congenital adrenal hyperplasia |
What happens to hormones during Congenital adrenal hyperplasia? | Decreased cortisol = increased ACTH to adrenal androgens to masculrize external genitalia |
Sexual disorders: Male XY but outwardly female | Androgen sensitivity syndrome |
What happens during androgen sensitivity syndrome? | No internal ducts develop
- breasts develop
- Androgens converted into E targeted tissues
- Infertile |
What triggers the onset of puberty? | Increased secretion of GnRH from pulse generator
-> increased LH/FSH -> increased sex steroids -> puberty changes |
How does follicular depletion happen? | Apoptosis |
What does decreased follicle #'s and decreased responsiveness to gonadotrophs do to E? | Decreased E and inhibin |
What does no ovulation mean for progesterone? | No corpus luteum = decreased progesterone |
What does decreased E, inhibin, and P do to FSH and LH? | Removes neg feedback inhibition = increased FSH/LH |