29.01.25 Flashcards
(25 cards)
What is menopause in women?
A finite number of ovarian follicles, reduction in hormones by ovary in response to gonadotrophins, hypothalamic-pituitary-ovary axis shuts down, resulting in hot flushes, sleeping difficulties, and mood swings.
What is an egg in humans?
A single germ cell with haploid nucleus, surrounded by somatic non-germ cells, released by ovulation.
What is a chicken egg?
An already fertilized zygote within an enclosed structure, expelled from the mother reproductive tract.
What are cleidoic eggs?
Eggs with an external membrane that provides nutrition and protection, preventing desiccation and infection, allowing gas exchange.
How are gamete-containing eggs fertilized in birds, mammals, and some vertebrates?
Internally by sperm through copulation, leading to embryo development either internally, in cleidoic eggs, or outside.
What are viviparous animals?
Animals that deliver young to the external environment.
What are oviparous animals?
Animals that give birth to young that have developed from cleidoic eggs.
How do invertebrates, fish, and amphibians reproduce?
They release gamete-containing eggs to the environment, with fertilization occurring outside.
What is microlecithal yolk?
Very little or no yolk, found in all eutherian mammals and some marine animals.
What is centrolecithal yolk?
Yolk and haploid germ cell located centrally, found in insects, other arthropods, and cnidaria.
What is mesolecithal yolk?
Moderate amount of yolk, unevenly distributed, found in amphibians and teleost fish.
What is macrolecithal yolk?
A large amount of yolk, unevenly distributed, found in birds, reptiles, and some mammals.
What is viviparity in mammals?
The placenta allows the birth of free-living young that develop inside the mother and depend on her after birth.
What are marsupials?
Animals that have a pouch for young, with short development in the uterus and provide protection and milk.
What are monotremes?
Egg-laying mammals that have young that take milk from mammary glands and exhibit long parental care.
What is the function of the acrosome in sperm?
It is derived from the Golgi and contains enzymes necessary for penetrating the zona pellucida.
What are the stages of fertilization?
- Attraction and activation of sperm by female reproductive tract
- Sperm binds to zona pellucida
- Release of enzymes from acrosome to lyse hole
- Passage of sperm through zona
- Fusion of sperm and oocyte plasma membrane
What is schizotomy in annelid reproduction?
A form of asexual reproduction involving fission.
What is parthenogenesis in insects?
Production of unfertilized eggs which result in female or male offspring.
What are the three types of metamorphosis in insects?
- Incomplete (hemimetaboly)
- Complete (holometaboly)
- No metamorphosis
How do fish reproduce?
They fertilize eggs externally, releasing eggs and sperm into the water.
What is the metamorphosis process in amphibians?
Hatchling is a tadpole with external gills, growing hind legs, front legs, and then losing the tail, controlled by hormones from the thyroid.
What are angiosperms?
Flowering plants that undergo meiosis in both male and female organs.
What are gymnosperms?
Non-flowering plants, such as conifers and cycads.
