Human Reproduction Flashcards
Give the function of the seminiferous tubules
Spermatogenesis
Give the function of the epididymis
Sperm collect and mature here
Give the function of the vas deferens
The tube that takes sperm from testis to urethra during ejaculation
Give the function of the seminal vesicle
Releases nutrients which sperm can use for respiration to swim
Give the function of the prostate gland
Releases alkaline fluid to neutralise acidic urine
Give the steps of spermatogenesis in order
Germinal epithelium (mitosis)->, spermatogonia (mitosis and growth)-> primary spermatocytes (meiosis 1)->secondary spermatocytes (meiosis 2), spermatids (differentiation)-> spermatozoa
Which cells nourish and protect developing sperm in the seminiferous tubules?
Sertoli cells (nurse cells)
Which cells in the testes release testosterone?
Leydig cells (also called interstitial cells)
What is the name for the lysosome found in the head of a sperm cell, and what is its function?
Acrosome. Releases digestive enzymes during the acrosome reaction to hydrolyse the zona pellucida
What are the terms for the inner lining of the uterus that sheds, and the muscular layer below?
Endometrium (lining) and myometrium (muscle layer)
What are the first haploid cells produced in spermatogenesis?
The secondary spermatocytes
What are the terms for the inner lining of the uterus that sheds, and the muscular layer below?
Endometrium (lining) and myometrium (muscle layer)
What is the name of the muscular ring at the neck of the uterus?
Cervix. This dilates during labour
What steps of oogenesis occur before birth?
Germinal epithelium (mitosis)->,oogonia (mitosis and growth)-> primary oocytes (begin meiosis 1 but stop at prophase 1). The primary oocytes are found in primary follicles
What steps of oogenesis occur each month after puberty?
Each month FSH is released from the pituitary gland and causes some primary oocytes to finish meiosis 1, forming secondary oocytes and 1st polar bodies in secondary follicles. One of these fully develops to a Graafian follicle and bursts (ovulation), releasing the secondary oocyte from the ovary
What steps of oogenesis occur after fertilisation?
When the sperm fuses with the secondary oocyte it finishes meiosis 2, forming an ovum and a second polar body. When the nucleus of the sperm fuses with the nucleus of the ovum it is a diploid zygote
What is the name of the single fully developed follicle that forms in an ovary each cycle, and the name of the fluid filled space within it
Graafian follicle, fluid filled antrum
Name the layer of glycoproteins that surrounds a secondary oocyte and the layer of cells on the outside of this that sperm must pass through
Zona pellucida (glycoprotein layer) and corona radiata (cells)
What does FSH stand for and where is it released from?
Follicle stimulating hormone, the anterior pituitary gland
What does LH stand for and where is it released from?
Luteinising hormone, the anterior pituitary gland
What is the function of FSH?
It stimulates primary follicles to begin developing into secondary follicles and stimulates thecal cells in the Graafian follicle to release oestrogen
What does oestrogen do in the first half of the menstrual cycle (follicular phase)
Causes the rebuilding of the endometrium, inhibits FSH secretion and stimulates LH secretion
Give two functions of LH
Causes ovulation, causes the burst Graafian follicle to become the corpus luteum
Which hormones are produced by the corpus luteum?
Oestrogen and progesterone
What is the function of progesterone in the menstrual cycle?
Maintains the endometrium to prevent shedding, thickens it further, inhibits release of FSH and LH
What causes the endometrium to shed in the menstrual cycle?
After 14 days, if there is no implantation, low LH and FSH cause the corpus luteum to breakdown, reducing its release of progesterone. This allows the endometrium to shed
Where does fertilisation occur?
The beginning of the fallopian tubes
What process happens to sperm as it swims through the fluid of the uterus?
Capacitation. The membrane covering the acrosome becomes more fluid and influx of Ca2+ increases motility
How does the secondary oocyte prevent polyspermy?
The cortical reaction. Enzymes released by exocytosis from cortical granules harden the zona pellucida to prevent further sperm entering
Name the hollow ball of cells formed by mitosis of the diploid zygote
The blastocyst. Division of cells to form this is called cleavage
Which hormone is released from the blastocyst and what is its function?
Human Chorionic Gonadotropin (HCG). This is detected in a pregnancy test. It prevents the corpus luteum breaking down, so it continues to release oestrogen and progesterone
Where do oestrogen and progesterone come from after the second month of pregnancy?
They are released by the placenta
List five functions of the placenta
Production of progesterone and oestrogen (replacing the corpus luteum), Exchange of O2 / CO2, nutrients / wastes, A barrier to high blood pressure, bloodborne pathogens and toxins in maternal blood, Allows maternal antibodies to protect the foetus, Prevents antibodies attacking the foetus
Which blood vessels carry deoxygenated blood away from the foetus?
The foetal arteries
Which blood vessel carries oxygenated blood towards the foetus?
The foetal vein
Why is maternal blood in the placenta in lacunae?
It can bathe the foetal capillaries, shortening the diffusion distance as oxygen does not have to pass through maternal capillary walls
Give the functions of the amniotic fluid in the amniotic sac
Maintaining temperature, Providing lubrication, Contributing to lung development, Allowing movement, Acting as a shock absorber
What does oestrogen do during pregnancy?
Inhibits release of FSH, stimulates the growth of the uterus to accommodate the foetus and causes growth and development of the mammary glands
What does progesterone do during pregnancy?
Inhibits release of FSH and LH, suppresses uterine contractions
Where is oxytocin secreted from and what is its function?
Oxytocin is secreted by the posterior pituitary gland and causes contractions of the myometrium. After birth it causes contractions of milk ducts in lactation
Where is prolactin secreted from and what is its function?
Prolactin is secreted by the anterior pituitary gland and stimulates the mammary glands to synthesise milk.
