Chp 51 EXAM 4 Flashcards
Can animals asexually reproduce? Name all of the processes that are used.
Yes they can. 3 major forms:
Budding- A piece of the parent organism pinches off to form new one
Regeneration- Complete organism formed from fragment of the parent body
Parthenogenesis- Development of offspring from unfertilized eggs (always female) (EX of asexual reproduction)
What is the difference between sexual and asexual reproduction?
Sexual: Meiosis
*Production of a new individual by the joining of 2 haploid gametes
*Haploid Egg+Sperm=Diploid Zygote
*Allows more rapid adaptation to environmental changes
Asexual: Mitosis
*Offspring are clones of parent
Gametogenesis-
production of gametes
2 possibilities
Spermatogenesis
oogenesis
Describe spermatogenesis and oogenesis.
Spermatogenesis-
* Primary spermatocytes undergo meiosis I to produce 2 haploid secondary spermatocytes
* Undergo meiosis II to produce 4 haploid spermatids
* Eventually become sperm
* 1 cell becomes 4 gametes
* Sperm has head (with acrosome), midpiece, and tail
Oogenesis-
*Unlike males, females will only form 1 gamete from each primary oocyte
*Each meiotic division results in 1 large cell (secondary oocyte in meiosis I and ovum in meiosis II) and 1 small cell (polar body)
*One or many ova can develop at a time
*2 layers around ova (zona pellucida and cumulus mass)
Does semen contain just sperm?
No, Semen and fluid
Sperm about 5% of volume
Fluid from seminal vesicles (fructose) {2/3}
bulbourethral glands (alkaline mucus) {3-5%}
prostate gland (protective fluid) {1/3}
Describe the hormones in the male reproductive system, what kind of system are they regulated by.
Testosterone
Gonadotropin-releasing hormone (GnRH)- made by the hypothalamus stimulates the anterior pituitary to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH)
LH- stimulates Leydig cells to produce testosterone
FSH (with testosterone) - stimulates Sertoli cells and spermatogenesis
All are regulated by negative feedback
SLIDE 16
Identify and define the function of each part of the female reproductive tract.
SLIDE 20
2 layers around ova (egg)- zona pellucida and cumulus mass
Mature ovum- Stays
Second polar body- degenerates
Ovary- egg develops
Oviduct- Completely lined with cilia that cause fluid to flow in 1 direction
What is the corpus luteum and what does it produce?
An empty follicle during ovulation when follicle ruptures to release egg
Progesterone
What is the function of the follicle cells?
They provide structural support, nourishment, and hormonal regulation necessary for successful follicular development, ovulation, and female fertility.
Compare oogenesis in females to spermatogenesis in males. What is the difference in time period and longevity of process? Who can produce more?
Timing and Location: Oogenesis begins during fetal development, where oogonia (precursor cells) undergo mitotic divisions to form primary oocytes. Spermatogenesis begins at puberty and occurs continuously throughout a man’s reproductive life within the seminiferous tubules of the testes
Quantity Produced: In humans, only one mature egg (secondary oocyte) is typically produced during each menstrual cycle. Spermatogenesis results in the production of vast quantities of sperm cells
What is an ectopic pregnancy?
When the released egg gets stuck and grows in the oviduct
What is menopause?
the ovaries gradually decrease their production of estrogen and progesterone, resulting in changes to the menstrual cycle and eventually the cessation of menstruation altogether. typically occurs as a result of the natural depletion of ovarian follicles over time.
How does an egg attract a sperm? and what’s the process of it fertilizing it?
Chemical attraction called chemotaxis
Will only be attracted to same species
*Sperm swims up to chemical gradient then uses proteolytic enzymes(in acrosome) to digest and breakthrough Zona pellucida, receptors on egg mem. identify species
Compare and contrast Internal and external fertilization.
External: Eggs+Sperm released closely in oceans or freshwater (so gamete doesn’t dry out), usually it’s a lot of eggs
Internal: Sperm released IN female. Why? protects gametes from hazardous conditions.
Fast block to polyspermy-
fusion of egg and sperm causes depolarization (ion channels open) of eggs so no more sperm can enter
