fertilisation Flashcards
What does the acrosome contain?
Hydrolytic enzymes
What is the function of the midpiece in sperm?
It is made up of lots of mitochondria, providing energy for movement.
What is the function of the flagella in sperm?
Responsible for movement of the sperm.
What is the role of the seminal vesicle?
Accounts for 60-70% of seminal fluid and produces fructose, a carbohydrate energy source for sperm.
What do prostaglandins do in the reproductive process?
Act on the smooth muscle of the uterus to stimulate contractions, moving sperm up the reproductive tract.
What is the function of coagulase in seminal fluid?
Allows sperm to latch onto the vaginal walls; sperm that do not latch on are lost.
What is the function of fibrinolysin in seminal fluid?
Breaks up some of the coagulation, releasing sperm into the uterus.
What is the role of relaxin in sperm motility?
Works on sperm to speed up motility.
What happens during Stage 1: Capacitation?
The sperm undergoes “cleaning off,” removing cholesterol and proteins from its head, leaving modified glycoproteins, and inducing hypermotility.
What happens during Stage 2: Acrosomal Reaction?
The sperm migrates toward the egg’s zona pellucida, binds to the ZP3 receptor, and releases digestive enzymes (e.g., acrosin, proteases) that break down the zona pellucida.
What occurs during Stage 3: Block to Polyspermy?
The sperm binds to the ovum’s protein, opening Na+ channels and causing an influx of Na+, leading to a positive charge across the membrane and inhibiting other sperm from binding.
What is the function of prostate glands in the male reproductive system?
They account for about 30% of seminal fluid and produce citrate (an energy source) and fibrinolysin.
What is the role of citrate in seminal fluid?
Citrate serves as an energy source for sperm
What is the role of fibrinolysin produced by prostate glands?
Fibrinolysin breaks up some of the coagulation to release sperm into the uterus.
How does fructose contribute to sperm function?
Fructose acts as an energy source for sperm and is broken down into ATP by mitochondria, which is used for motility.
How do prostaglandins help sperm during fertilization?
Prostaglandins stimulate uterine smooth muscle contraction, which moves sperm upwards into the reproductive tract.
What happens to sperm that don’t latch onto the vaginal walls using coagulase?
Any sperm that don’t latch onto the vaginal walls are lost.
What triggers the influx of sodium (Na+) in the egg during fertilization?
The sperm binds with a protein on the ovum, which opens Na+ channels, leading to an influx of Na+.
What is the significance of the positive charge created across the ovum membrane during fertilization?
The positive charge prevents additional sperm from binding to the egg, ensuring only one sperm fertilizes the egg.
What is the purpose of the “cleaning off” of the sperm’s head during capacitation?
The removal of cholesterol and proteins from the sperm’s head exposes specific glycoproteins and prepares the sperm for fertilization.
