Gametogenesis Part 2

Question 1

what is oogenesis

Answer 1

primordial cell to ova

Question 2

discuss oogenesis at prenatal

Answer 2

begins in fetus - primordial germ cell replicate via mitosis

Question 3

oogenesis at 3rd month

Answer 3

oogonia arranged in clusters surrounded by follicular cells (single flat epithelial cells)

Question 4

oogenesis at 5th month

Answer 4

oogonia at peak development - 7 000 000

Question 5

oogenesis at 7th month

Answer 5

majority of oogonia degenerates and those that survive become primary oocytes and enter meiosis 1

about 2000000 survive

Question 6

primary oocytes + single flat epithelial cell

Answer 6

primordial follicle

Question 7

discuss oogenesis at antenatal

Answer 7

at birth - all primary oocytes are at prophase of meiosis 1 and rests at diplotene

OMI or oocyte maturation inhibitor arrests oocytes at diplotene = freeze

Question 8

discuss oogenesis at puberty

Answer 8

only one oocyte reaches full maturity each month - ovarian cycle

meiosis 1 is completed d/t luteinizing hormone (LH) = 2 haploids but only one secondary oocyte survives

if sperm fertilizes it goes to meiosis 2

no sperm egg dies

Question 9

discuss oogenesis at menopause

Answer 9

there are only 500 eggs available hence there will come a time that there will be no more eggs to ovulate

Question 10

discuss oogenesis at fertilization

Answer 10

secondary oocyte will enter meiosis 2 but arrests at metaphase - around 3 hrs before ovulation

only upon fertilization will it continue otherwise it degenerates

Question 11

discuss spermatogenesis in general

Answer 11

begins at puberty when sertoli cells nurture spermatogonium in seminiferous tubules

ends when haploid motile sperm cell sloughs off inner wall of ST

Question 12

discuss spermatogenesis at primary spermatocyte

Answer 12

produced from mitosis of 1 spermatogonium @ seminiferous tubules

undergoes meiosis 1 = 2 diploid secondary spermatocytes

Question 13

discuss spermatogenesis at secondary spermatocyte

Answer 13

2 diploid secondary spermatocytes undergo meiosis 2 @ seminiferous tubules = 4 spermatids (haploid)

Question 14

discuss spermatogenesis at spermatids

Answer 14

matures in sperm with heads and tail = motile

Question 15

golgi phase of spermiogenesis

Answer 15

spermatid acquires prepared for head, mid piece and tail

golgi appraatus produces lytic enzymes that will form that acrosome or cap

mitochondria will fill in the mid piece

DNA undergoes packing at protamines - inactive

Question 16

cap phase of of spermiogenesis

Answer 16

golgi surrounds anterior of spermatid = acrosome

Question 17

tail phase of spermiogenesis

Answer 17

elongation of microtubules on one side of centrioles will form an axoneme in 9 + 2 configuration

pair of microtubules at center surrounded by 9 doublet microtubules

tail is oriented towards center of lumen of ST

Question 18

maturation phase of spermiogenesis

Answer 18

sertoli cells phagocytosis the remaining cytoplasm and organelles

final product - non motile spermatozoon; sterile

becomes motile in epididymis

migrates to epididymis via spermiation

Question 19

discuss the head of sperm

Answer 19

has haploid nucleus and acrosome that contains enzymes to penetrate the egg

Question 20

discuss the middle piece of sperm

Answer 20

full of mitochondria that converts glucose into ATP for tail movement

Question 21

discuss the tail of sperm

Answer 21

flagellum

Question 22

this refers to changes to the structure or number of chromosomes

Answer 22

chromosomal abnormalities

Question 23

discuss deletion

Answer 23

common - short arm of chromosome 5 or cri du chat syndrome

reduced head size and high pitched crying

Question 24

discuss inversion

Answer 24

genetic material is flipped in opposite direction mostly affects chromosome 2 and does not cause disease

Question 25

discuss duplication

Answer 25

extra genetic material duplication of chromosome 17 = weakness

Question 26

discuss translocation

Answer 26

piece of one chromosome detached and attached to another

Question 27

trisomy 21

Answer 27

most common trisomy - produced from mitosis of spermatogonium extra chromosome 21 - down syndrome dysmorphic: small head and flat face and CV problems

Question 28

trisomy 18

Answer 28

edwards syndrome severe mental disability, clenched hands, large back of head, small mouth, rocker bottom foot

Question 29

trisomy 13

Answer 29

patau syndrome severe mental disability, clenched hands, large back of head, small mouth, rocker bottom foot

Question 30

klinefleter syndrome

Answer 30

XXY - 7 chromosomes found in males sterile, testicular atrophy, hyalinization of ST, gynecomastia

Question 31

turner's syndrome

Answer 31

monosomy compatible for life = 45 chromosomes, X karyotype absence of ovaries, short stature, webbed neck and wide spaced nipples

Question 32

triple X syndrome

Answer 32

47 - XXX mild physical features and girls have problems with speech and self esteem AKA super female