Developmental Bio Flashcards
Function of epididymus
Sperm storage and maturation
Vas deferens function
Transfers sperm to urethra
Function of penis
Transfers sperm to outside, houses urethra
Function of seminiferous vesicles
Secrete substances that aid with ejaculation
Function of prostate gland
Neutralizes acidity of vagina
Bulbourethral glands
Secrete fluids that lubricate urethra
Process of sperm generation
Starts in seminiferous tubules. Spermatogonia stem cells undergo mitosis to become primary spermatocytes. Meiosis I occurs. Secondary spermatocytes. Meiosis II occurs. Spermatids. Spermatids travel to epididymis to mature, becoming spermatozoa. Nourished by sertorli cells
Components of sperm head
Nucleus and Acrosome
Acrosome
Located in interior of sperm head. Has enzymes necessary for penetrating the egg. From Golgi apparatus.
Contents of neck of sperm
Contains mitochondria
Sperm tail is made up of ______
Flagella
Ovaries
Site of ovum storage
Oviduct
Pathway from ovaries to uterus
Uterus
Contains endometrium
Endometrium
Cushion of blood cells where embryo develops
Cervix
Connects vagina to uterus
Process of oogenesis
Oogonium cells undergo mitosis to produce two primary oocytes. Primary oocytes undergo meiosis I but stop at prophase I until puberty. Meiosis I occurs and a secondary oocyte and polar body is produced. If the secondary oocyte is fertilized it becomes a ootid. Ootid becomes ovum.
Follicular Phase
Follicle secretes estrogen, allowing primary oocyte to become secondary oocyte
Ovulation
Mature ovum released from follicle (now called corpus lateum)
Luteal Phase
Corpus luteum secretes estrogen and proestrogen
Proliferative Phase
Endometrium thickens
Secretory phase
Endometrium is maintained by proestrogen from corpus luteum
Menstrual Phase
Endometrium is expelled through vagina
Name of a mature follicle
Corpus luteum
Ovulation occurs due to a spike in ?
LH hormone
Capacitation
Dissolving of sperm cholesterol coat upon entering the vagina
Pathway of sperm into ovum
Corona radiata, zone pellucida, acrosome releases digestive enzymes, fusion of sperm with ovum, meiosis II happens in ovum to finalize fertilization
Methods of blocking polyspermy
Fast block (depolarization), cortical reaction
Depolarization of fertilized ovum
Na+ enters ovum
Cortical reaction
Releases calcium 2+ , triggering the release of cortical vesicles which from a fertilization membrane
Monozygotic twins
Zygote divides into separate zygotes
Dizygotic twins
Two zygotes carrying different genetic material
Determinate Cleavage
Produces cells with a developmental fate. Found in protostomes.
Indeterminate Cleavage
Produces cells without a developmental fate. Common in deuterosomes.
Holoblastic cleavage
Occurs when little yolk is present (humans) Lead to even blastomeres
Meroblastic cleavage
Occurs with abundance of yolk. Lead to uneven blastomeres
Morula
Occurs after 8-cell stage. Allows for differentiation into outer trophoblast and inner intercellular mass
Blastula
Contains blastocoel. Zygote implants into the uterus
Gastrulation Process
Formation of endoderm, mesoderm, and ectoderm. Internal cavity arises.
What does the endoderm give rise to?
Digestive organs, lungs, etc
What does the mesoderm give rise to?
Heart, muscles, skeletal system
What does the ectoderm give rise to?
Skin, hair, nervous system
Process of neurulation
Mesoderm forms notochord, ectoderm forms neural plate. Neural tube becomes CNS. Neural crest becomes PNS.
Amnion
Innermost layer of embryo. Provides amniotic fluid to cushion embryo.
Yolk Sac
Nourishment to embryo in birds and reptiles
Allantois
Transports waste
Chorion
Forms placenta
What structure gives rise to the placenta?
Chorion
What structure gives rise to the umbilical cord?
Allantois
Function of yolk in birds and reptiles
Nutrition of embryo
Function of yolk in mammals
Site of RBC formation
Function of allantois in birds and reptiles
Site of uric acid excretion
Function of chorion in reptiles
Gas exchange
