4.1 Sexual Reproduction In Humans Flashcards
Where is FSH produced and what’s it’s role?
Anterior pituitary
Stimulate maturing of follicle
Stimulates Oestrogen
Where is LH produced and what’s it’s role?
Anterior pituitary
Stimulates ovulation
Develops Corpus luteum
Stimulates progesterone
Where is progesterone produced and what’s it’s role?
Corpus luteum and placenta
Maintains uterine lining
Inhibits LH and FSH
Where is Oestrogen produced and what’s it’s role?
Ovary and placenta
Rebuild endometrium
Stimulate LH
Inhibit FSH
Inhibit prolactin and oxytocin
Where is Oxytocin produced and what’s it’s role?
Hypothalamus, anterior pituitary
Contraction of uterine muscles
Contraction of smooth muscles in milk ducts
Where is prolactin produced and what’s it’s role?
Anterior pituitary
Milk synthesis
Where is hCG produced and what’s it’s role?
Blastocyst, placenta
Maintains corpus luteum
Where is testosterone produced and what’s it’s role?
Leydig cells
Sperm development
What is the function of the fallopian tube?
Connects the ovaries and the uterus allowing the ovum to travel during ovulation
What is the function of the scrotum?
provide protection to the testies
What is the role of the epididimus?
Storage of sperm
What is the role of the vas deferns?
Duct connecting epididymis and ejaculatory duct
What is the role of the testis?
Gland producing spermatozoa and hormones
What is the role of seminal vesicles?
Provide and energy source for sperm
produce alkaline secretions to neutralise acidic vagina
What is the role of the prostate galnd?
Additional fluid for ejaculation
What is the function of the male reproductive system?
To produce, maintain, transport and nourish sperm and seamen
What is the function of the female reproductive system?
Produce ova and hormones
Pass sperm to the egg
provide an implantation site for the development of a foetus
What is the role of the endometrium?
the lining of the uterus to prepare for implantation
What is the role of the seminiferous tubules?
The site of sperm production
Describe the steps of spermatogenesis
Diploid germinal epithelium(2n) divides by mitosis
–>spermatogonia(2n) then divides by mitosis
—> primary spermatocytes(2n) that divide by meiosis
–> secondary spermatocytes(n) in first division then spermatids(n) in the second
—> mature to form spermatozoa(n)
What are the adaptations of sperm for survival?
Axial filaments in the tail (tubules allow whipping propelling forward)
many mitochondria
condensed haploid chromatin
nucleus in had
acrosome containing protease(digestive enzyme)
Describe the process of Oogenesis
Before birth: germinal epithelium splits by mitosis making oogonia that grow to form primary oocytes
Primary oocytes divide by meiosis but stop at Prophase 1
Germinal epithelium cells divide to form primary follicles that surround the 1oocytes
During ovulation: 1 completes meiosis
–> 2* follicle containing 2* oocyte and a small polar body
–> matures to Graafian follicle
–> migrates to ovary surface and bursts to release oocyte
—> meiosis 2 begins but stops at metaphase 2 until; fertilisation
What happens to the Graafian follicle after ovulation?
forms the corpus luteum
What challenges does the sperm face?
pH of vagina
Muscle contractions
cervix
2 fallopian tubes and 1 egg
rejection by egg
What is the function of Sertoli cells?
provide nutrients to developing spermatozoa
What does the capacitation reaction do?
Increases the permeability of the acrosome membrane
What are the steps of the acrosome reaction?
Protease is released and digests the corona radiata
Upon contact with zona pellucida acrosome membrane ruptures
Hydrolase is released and digests the Zona pellucida
Membrane of sperm and 2*Oocyte fuse + genetic material of sperm enters
What are the steps of the Cortical reaction?
Cortical granules fuse with cell membrane and alter the zona pellucida to form a fertilisation membrane
Meiosis II completes creating a 2* polar body
2 nuclei fuse and zygotic nucleus is formed
What is a blastocyst?
A ball of cells formed 5-6 days after fertilization that implants into the endometrial lining
What is cleavage?
The mitotic division of a zygote to from a blastocyst
Where is HCG secreted from after fertilisation?
The blastocyst
What is the function of HCG
Inhibit FSH and LH
Maintain endometrium
Supress uterine contraction
(Prevents menstruation and formation of a new follicle)
What hormones are secreted by the placenta during pregnancy?
HCG
progesterone
Oestrogen
What does oestrogen promote during pregancy?
Development of mammary glandes
growth of uterus
What is the function of the chorionic Villi?
larger surface area for diffusion and blood flow
prevents maternal white blood cells entering the foetus’ blood
What is the function of the intervillous spaces?
Contain maternal blood and bathe villi
Prevents high maternal BP from entering the foetus
What is the function of the umbilical cord arteries?
Deoxygenated blood and waste materials to chorionic villi for gas exchange and excretion
What is the function of the umbilical veins?
Carries oxygenated blood and nutrients to the foetus
What is the function of the amniotic fluid?
Shock absorber
lung development
finger lubricant
temperature stabiliser
What hormones decrease to prepare for birth? Why?
Progesterone and oestrogen
They inhibit oxytocin and prolactin
What causes uterine contractions?
Secretion of oxytocin in a positive feedback loop
What secretes oxytocin?
Posterior lobe of pituitary gland
Where is prolactin secreted from?
Anterior lobe of pituitary gland
What does prolactin stimulate?
Production of milk in mammary glands
What are the main developments in the 1st trimester?
Major organs
What weeks are the first trimester?
0-12
What main developments occur in the 2nd trimester?
Organ development
What weeks are in the 2nd trimester?
13-28
What main developments occur in the 3rd trimester?
Growth
What is the Amnion?
A membrane derived from the inner mass of a blastocyst
it has contact with the embryo until amniotic fluid develops
It then is pushed to chorion (inner layer of placenta)
