human reproduction Flashcards
what is the scrotum
sac that holds the testes
- is a temperature regulator, 2/3 degrees lower than body temperature for formation of fertile sperm
- protection
What are the testes made up of [structure]
- many lobules containing highly convoluted tubules (seminiferous tubules)
- tubules lined with germinal epithelium
- between tubules are interstitial cells / cells of Leydig [group endocrine cells]
What are testes functions
- produce sperm by germinal layer
2. produce Testosterone by interstitial cells
Name all 3 ducts and their function in the Male reproductive system
- Epididymis
immature sperm enter this tubule and become fertile, motile and are stored
2.Sperm duct
muscular continuation of the epididymis, pushes mature sperm forward via peristaltic waves from epididymis into urethra [ejaculation]
- Urethra
common duct at the end of the uro-genital system leading to the exterior, both semen and urine.
What is the function of the prostate gland
secretes fluid containing enzymes which aids the transportation of sperm and makes them more active
[makes up 1/3 of seminal fluid]
Describe the structure of a penis
- penis consists of spongy erectile tissue which runs down the length of it.[3 sections]
- 2 situated on dorsal side [corpus cavernosa]
- 1 on ventral side [corpus spongiosum]
- urethra passes down the penis
What is the function of the fallopian tubes
- pathway between uterus and ovary for sperm, eggs and zygote
- site of fertilisation and initial cell division of the zygote
- enables egg/developing zygote to move towards uterus
What does the uterine wall consist of
myometrium [involuntary muscle layer]
-contractions of myometrium allow baby to be birthed
endometrium[richly suppled lining with blood vessels]
What happens to the endometrium during ovulation and if no fertilisation took place [menstruation]
at ovulation
-progesterone causes it to thicken to prep for implantation of blastocyst
no fertilisation
-upper layer of endometrium becomes detached and passes out vagina along with the unfertilised egg, every 28 days
What can puberty be classified as
process of physical and physiological changes leading to development of secondary sex characteristics and immature child becoming capable of reproduction
[period known as adolescence]
What initiates puberty
The pituitary gland gets stimulated by the hypothalamus to release gonadotropins
in males - ICSH stimulates testes to produce T
in females - FSH stimulates ovaries to produces O
Define Gametogenesis
formation of mature gametes
and involves meiosis for cell division from 46 chromo in body cells to 23 in gametes
=that way zygote has 46 chromosomes , 1/2 from mother and other 1/2 from father
List the phases in which mature haploid sperm are produced
[spermatogenesis]
1.multiplying phase
2.growth phase
3.reduction phase
4.differentiation phase
takes around 72days [look at notion for more detail]
What are the differences between Oogenesis and spermatogenesis
- mature eggs aren’t formed continuously like sperm
- oogenesis occurs in a monthly cycle
- egg number is determined before birth
What are the phases of Oogenesis, elaborate of them each
- Multiplying phase (before birth)
- germ cells from germinal epithelium surrounding the ovary sink in and divide by mitosis = primary follicles
- each follicle has a central cell [oogonium-2n] surrounded by theca [single layer] - Growth phase
- from puberty the primary follicles periodically grow to form Graafian follicles
- within these G follicles the oogonium grows in a primary oocyte [2n] - Reduction and maturity phase
- primary oocyte undergoes meiosis = egg [n]
- there is no splitting of the cell during this meiosis
- of the 4 haploid nuclei one will form the nucleus of the egg(others degenerate)
- Mature G follicles move periodically to the surface of the ovary where they burst = releasing mature egg and surrounding follicle cells AKA ovulation
