fertilisation Flashcards
In pigs, how many sperm reach the oviduct?
1 in 100,000
What stain is used to simply observe sperm on slides
Toluidine blue
How does live dead staining work?
-Based on plasma membrane integrity
-If the plasma membrane is compromised, the red dye mixture is able to get into the spermatozoa
How does JC-1 staining work?
-Mitochondrial membrane potential
- If the mitochondria are active, ie producing ATP, then the middle piece will show as yellow
How can flow cytometry be used when assessing sperm quality?
Can automatically assess the amount of sperm with specific dyes
Male factors affecting fertility: What problems can arise in the testis?
-Sperm assembly
-DNA condensation
Male factors affecting fertility: What problems can arise in the epididymis?
-Sperm maturation
-lipid and protein modification
-sperm storage
Male factors affecting fertility: What problems can arise in the seminal plasma?
-Accessory secretions
-adsorbance to sperm surface
Male factors affecting fertility: What problems can arise in the sperm transport?
-Highly complex interactions with the female tract
Which animal exhibit cooperative sperm swimming?
-South American marsupials
- Mice
Sperm selectivity: which species have intravaginal insemination and what prevents sperm entry to the uterus?
-Sheep
-Rodents
-Primates
-Cervical mucus and complex anatomy
Which species has transcervical insemination?
Pigs
What may prevent sperm entry to the oviduct via the UTJ?
-If the cell surface lacks specific proteins
-ADAM, calmegin and calreticulin
How does sperm binding to the OEC protect sperm?
Binding induces HSP synthesis, which enters the oviduct and protects the sperm surface
Which hormone secretion stimulates selective sperm chemotaxis and hyperactivation?
Progesterone
What process does sperm entry into the uterus induce?
Post-mating inflammatory response and leukocyte invasion
What does sperm selection at the UTJ involve?
-head and tail morphology
-swimming behaviour
-correct response to extracellular signals
What modulates gene expression in oviductal epithelial cells?
Sperm microRNA
What modulates sperm motility in oviductal fluid?
Bicarbonate
What reduces polyspermy and causes ZP hardening?
Oviductal fluid
In humans, what proportion of sperm reach the site of fertilisation?
1 in 30,000
How can sperm properties be assessed?
- Can assess using microscopy but this is limited
- should observe them in action
-Cervical mucus penetration test
-Migration efficiency
How can DNA contribute to poor sperm quality?
-Direct damage to purines/pyrimidines
-Single/double-strand breaks
-crosslinking
-chromosomal rearrangements
How can mitochondria contribute to poor sperm quality
Damage to mDNA causes decreased ATP production which causes impaired motility