3.1.5 Sexual Reproduction in Humans Flashcards
What is the Role of the Penis in the Male reproductive system?
Passes urine out of the body from the bladder and allows semen (sperm) to pass into the vagina of a woman during sexual intercourse.
What is the Role of the Testis in the Male reproductive system?
Contained in a bag of skin (Scrotum) and produces sperm and testosterone (hormone)
What is the Role of the Scrotum in the Male reproductive system?
Sac supporting the testes outside the body to ensure sperm at a temperature slightly lower than body temperature.
What is the Role of the Urethra in the Male reproductive system?
A tube running down the center of the penis that can carry out sperm or urine, a ring in the Urethra prevents the sperm and urine from mixing.
What is the Role of the Prostate Gland in the Male reproductive system?
Produces fluid called semen that provides sperm cells with nutrients.
What is the Role of the Sperm Duct in the Male reproductive system?
Sperm passes through the sperm duct to be mixed with fluids produced by the glands before being passed into the urethra for ejaculation.
What is the Role of the Oviduct in the female reproductive system?
Connects the ovary to the uterus and is lined with ciliated cells to push the released ovum down it. Fertilization occurs here
What is the Role of Ovary in the female reproductive system?
Contains Ova (Female Gamete) which will mature and develop when hormones are released.
What is the Role of the Uterus in the female reproductive system?
Muscular bag with a soft lining where the fertilized egg (Zygote) will be implanted to develop into a fetus
What is the Role of the Vagina in the female reproductive system?
A muscular tube that leads into the inside of a woman’s body, where the male penis will enter during sexual intercourse and where sperm are deposited
What is the Role of the Cervix in the female reproductive system?
Ring of muscle at the lower end of the uterus to keep developing fetus in place during pregnancy
A gamete is a :
Sex cell, in animals: sperm and ovum; in plants pollen nucleus and ovum
Why do gametes differ from normal cells?
Gametes differ from normal cells as they contain half the number of chromosomes (23) found in other body cells (46). This is because they only contain one copy of each chromosome, rather than the two copies found in other body cells
In human beings, a normal body cell contains how many chromosomes
46 chromosomes
How many chromosomes are in each gamete
each gamete contains 23 chromosomes
Name all the 4 structures of a sperm cell
#1. Flagellum (tail) #2. Haploid Nucleus #3. Acrosome #4. Midpiece containing Mitochondria
What is a Haploid Nucleus
A cell nucleus with half the normal number of chromosomes (sperm and ova)
Name all the 4 structures of an egg cell
#1. Cell Membrane #2. Cytoplasm #3. Haploid Nucleus #4. Mitochondria
(Adaptive Features Sperm) has a flagellum:
Reason: The flagellum enables the sperm cell to swim to the egg.
(Adaptive Features Sperm) Contains enzymes in the head region (Acrosome)
Reason: To digest through the jelly coat and cell membrane of an egg cell when it meets one.
(Adaptive Features Sperm) Contains many mitochondria
Reason: Provides energy from respiration so that the flagellum can move back and forth for locomotion.
(Adaptive Features Egg) Cytoplasm containing a store of energy
Reason: Provides energy for dividing the zygote (fertilized egg) after fertilization
(Adaptive Features Egg) Jelly like coating that changes after fertilization
Reason: Forms an impenetrable barrier after fertilization to prevent other sperm nuclei from entering the egg cell.
What is the size of the Sperm and Egg Cell
Sperm: 45 Micrometers
Egg: 0.2 Millimeters
What is the Description of the structure of the Sperm and Egg Cell
Sperm: Head Region and Flagellum, many structural adaptations.
Egg: Round cell with few structural adaptations covered in a jelly coating
What is the movement of the Sperm and Egg Cell
Sperm: Capable of Locomotion
Egg: Not capable of Locomotion
What are the production numbers of the Sperm and Egg Cell
Sperm: Produced every day, around 100 million per day.
Egg: Thousands of immature eggs in each ovary, but only one is released each month.
During ejaculation in the male, millions of sperm cells move along the sperm duct, also known as the:
vas deferens
The sperm are suspended in:
Semen, a fluid secreted by the prostate gland
The semen passes into the:
urethra
Describe the entire process of fertilization.
1. During sexual intercourse, semen is ejaculated into the vagina of the female, near the cervix
#4. If a sperm cell meets an egg cell in the oviduct, fertilization can occur - This is most likely to occur 1-2 days after the female has ovulated (released an egg cell from one of her ovaries into an oviduct)
Fertilization is the fusion of the nuclei from:
A male gamete (Sperm) and a Female Gamete (Egg Cell)
During fertilization, the head of a sperm cell releases enzymes, why?
To digest a path through the protective outer layer of the egg cell, allowing the sperm to pass through the egg cell membrane.
Once this occurs, the egg cell immediately releases a thick layer of material that prevents any more sperm cells from entering, ensuring only one sperm cell can fertilize the egg cell
When the male and female gametes fuse, what do they become?
A zygote (fertilized egg cell)
How many chromosomes does a zygote contain
This zygote contains the full 46 chromosomes
The zygote divides by mitosis to form two new cells, which then continue to divide like this until, what?
An embryo (early stage of development) is formed after a few days.
