Reproductive System Flashcards
What are examples that show that the reproductive system isn’t essential in maintaining homeostasis?
- getting pets fixed
- Hysterectomy (ovaries/uterus removed)
- Castration: 2 young boys had testes removed to keep voice high-pitched, both lived past 70
Describe the testis
= site of hormone and sperm production
- cased in tough capsule (for protection)
- located inside the scrotum (which is outside of the body in humans)
- Being outside of the body allows
- Cooling (testis must have a temp. lower than body)
- Cremaster muscles can elevate it to regulate temp.
Function of the VAS DEFERENS
= muscular tube that helps expel/propel sperm
(can also store some sperm)
- cut and tied off in vasectomy procedures
Function of the EPIDIDYMUS
- sperm storage (can store over a month’s supply)
- site of maturation
Function of the SEMINIFEROUS TUBULES
- make sperm; 100s packed in together
- produce hormones (mainly testosterone)
- 3 components: Sertoli cell, Leydig cell, Spermatocytes
Function of SERTOLI CELL
- support and regulate spermatogenesis (produce substances that help)
- makes up the wall of the tubule
Function of LEYDIG CELL
- produces testosterone (which diffuses into sertoli and nearby blood vessels after)
- found outside of the tubule, near blood vessels
Function of SPERMATOCYTES/SPERMATOGONIA
= sperm cells
- populate the seminiferous tubules prior to birth, start dividing once sufficient testosterone (aka at puberty)
Describe Spermatogenesis
- initiated at puberty (point where sufficient testosterone)
Spermatogonia (diploid) –> 1˚ spermatocytes –> 2˚ spermatocytes
–> spermatids (haploid) –> spermatozoa
Describe Testosterone and its properties
- Steroid hormone (hydrophobic, lipophilic … therefore, can cross membranes easily)
- Made from cholesterol (= the precursor)
- Androgen-Binding protein –> needs to a protein to transport it to thru blood and make it soluble
- Intracellular receptors that allow testosterone to bind and promote/inhibit transcription –> since it works at this DNA level, takes longer for effects to take place since must make proteins from scratch
- Precursor for DHT and estradiol
- Regulated by the hypothalamic-anterior pituitary feedback pathway
Functions of Testosterone in males
- negative feedback
- spermatogenesis
- secondary sex characteristics
- anabolic reactions (increase muscle mass)
What are the side effects of exogenous testosterone?
It will increase muscle mass but….
- shuts off LH/Leydig/testosterone production
- decreases sperm count
- results in testicular atrophy
Semen (other secretions + their origins)
Seminal Vesicle: 60%
- fructose –> energy source
- clotting proteins (alkaline) –> semen clots to retain in female for a short period of time
Prostate Gland: 30%
- citric acid –> energy source
- enzymes (slightly acidic) –> various functions, one stops clotting so it can move through female
Bulbourethral Gland: minor concentration
- mainly mucus (alkaline) –> protects sperm from acidic environment of vagina
Describe Prostate Enlargement/Prostate Cancer
- urethra passes right through the prostrate, therefore when the prostate is enlarge it prevents the urethra from draining and you from peeing
- Diagnosis: digital rectal exam to check for size
Define OVARIES
= site of production of sex hormones and reproductive cells
- 2 paired ovaries suspended on other side of the uterus (in upper pelvis)
What are the Major Differences between Spermatogenesis and Oogenesis
Spermatogenesis = initiated at puberty
- small amount before birth
- need testosterone to initiate
- constant division: both meiosis I and II happen consequently
- 1 spermatogonia: 4 spermatozoa
Oogenesis = well on its way at birth
- all the oocytes are made before birth
- just before birth, all are converted to 1˚ oocytes
- sit dormant until puberty
- after puberty: once a month, some divide into 2˚ oocyte
- meiosis II happens ONLY if fertilized
- 1 oogonia: 1 2˚ oocyte
Define ATRESIA
= degeneration/reabsorption of oogonia/oocytes
- starts before birth (leaves us with ~ 500 000 1˚ oocytes at birth)
- atresia continue after birth, resulting in 450 menstrual cycles (oocytes) throughout your lifetime
Define FOLLICLE
= oocyte + surrounding cell that support/promote maturation
Function of GRANULOSA CELLS
- support cells
- cuboidal shaped instead of flat
Define UTERUS
= site of implantation of zygote
Define FALLOPIAN TUBE
= passage for sperm/oocyte
- sperm travel up fallopian tubes were ovum is slowly travelling through
Define VAGINA
= site of sperm deposition and removal of menstrual fluid
Define FIMBRIAE
“catcher’s glove”
- oocyte is released by ovary and caught by fimbriae
- fimbriae sweeps it into the fallopian tube where it’s swept along (the oocyte itself isn’t motile)
Define ENDOMETRIUM
= inner lining of uterus (Menses = shedding of this)
What are the other effects of female sex hormones on the body?
Estrogen and Progesterone are both important in:
- bone health (increase bone density)
- protects hearing
- breast changes
Estrogen is also protecting of cardiovascular health (after menopause, decreased estrogen = increased heart disease)
How do oral contraceptive pills influence the monthly cycle?
- keeps hormone levels stable (no LH surge, no increased estrogen = suppresses ovulation)
- changes in uterine environment make zygote less likely to implant (if ovulation/fertilization did occur)
- women bleed for less time, making menses lighter
- uses negative feedback to work
Describe Endometriosis (+ treatments)
= endometrial tissue enters abdomen (plants itself on different organs all throughout the body, even brain/nose)
- behaves like endometrial tissue in these foreign areas
- tissues bleeds –> internal bleeding in foreign areas, cramps
- if cysts bursts, then endometriosis spreads
Treatments: endometriosis is linked to high estrogen
- therefore, slow the process using birth control
- can also remove ovaries to stop hormonal input (causes infertility)
Define Menopause and describe the change that occur during it
= end of menses, end of reproductive stage (can no longer become pregnant)
- ovaries become less responses, decreased hormone synthesis
- don’t produce estrogen and progesterone (fall to the same levels as men)
- follicle pool decreases
- hot flashes, lack of sleep, CNS (mood) changes
- average age of onset = 50
Sperm must have the ability to…
- swim to read the ovum
- bind and fuse with the ovum
- penetrate the zona pellucid for fertilization
What are parts and characteristics of a sperm cell?
HEAD: nucleus (23 chromosomes) + acrosome (enzymes that degrade environment like a torpedo)
MID PIECE: mitochondria for ATP production (drives swimming motion)
TAIL: flagellum; allows for swimming motion)
Describe CAPACITATION
- sperm is coated in cholesterol (it caps the head)
- this ensures that the acrosome is not released at the wrong time
- as the sperm travels through and hits the female tract, it will encounter the fluid/natural lubrication present
- this degrades the cholesterol coating, removing the cap and revealing the acrosome –> can now penetrate the ovum
The window for pregnancy is generally about…
3 days (ovum fertilized within 12-24hrs otherwise it dies + sperm able to survive for 48hrs)
Where does fertilization occur?
In the upper 1/3 of the fallopian tube (sperm meets ovum near the fimbriae)
Describe the route sperm must travel for fertilization to occur
Spermatozoa enter through VAGINA –> some make it to thru the CERVIX –> Sperm can detect which FALLOPIAN TUBE the oocyte is in and goes near the Fimbriae to meet the ovum
Define ZONA PELLUCIDA
= gelatinous layer covering ovum outside of the cell membrane
What are the functions of the placenta?
- providing nutrients to the fetus for growth and development
- gas exchange between fetus and mother
- removal of fetal waste products
- acts as endocrine tissue
