Topic 16 (Reproduction in humans) Flashcards
What are the main parts of the male reproductive system?
Penis, sperm duct, testis, scrotum, urethra, prostate gland.
What are the main organs of the female reproductive system?
Ovaries, fallopian tube, uterine lining, uterus, vagina, egg cell, cervix.
What are the differences between male and female gametes? (male gametes)
Structure:
*Has a head, a middle piece and a tail
*Nucleus contains either X and Y chromosome
*About 60 μm long, with a head that has a
diameter of 2.5 μm
Motility:
*Motile
*Has a tail that enables it to swim towards the
oviduct
Number:
*Numerous sperm are produced throughout life
from puberty onwards.
*A large number of sperm is released per
ejaculation.
What are the differences between male and female gametes? (female gametes)
Structure:
*Spherical in shape
*Nucleus has one X chromosome
*Diameter of 120 150 μm
Motility:
*Non motile
*Passive movement of egg along the oviduct is
due to the action of cilia along the oviduct and
peristalsis of the oviduct wall.
Number:
*Number of eggs is determined at birth.
*Only one egg is released per month. Both
ovaries together produce about 500 mature
eggs.
What is puberty?
Puberty is the stage of human growth and development in which a person is physically mature.
What are the secondary sexual characteristics in males?
Facial hair starts to grow. Hair appears in the pubic
region and under armpits.
The penis and testicles increase in size.
Larynx enlarges and voice deepens.
Production of sperm starts.
What are the secondary sexual characteristics in females?
Hair appears in the pubic region and under armpits.
The breasts and uterus enlarge.
Hips broaden.
Menstruation and ovulation start.
What is the sign of puberty for females?
A sign of puberty for a female is usually the monthly discharge of blood or menses from the uterus via the vagina.
This is called menstruation.
What is the menstrual cycle?
Menstrual cycle is the cycle of events that takes place in the female reproductive organs every month. The
average menstrual cycle is 28 days , but this can vary.
When does the menstrual cycle permanently stop?
As a female ages, the ovaries will eventually stop releasing eggs and the menstrual cycle will stop. This is called
menopause . Menopause usually takes place between 45 and 55 years of age.
What happens if no fertilisation occurs?
*The egg breaks down.
*The corpus luteum breaks down and blood progesterone level decreases.
*On the 28th day, without progesterone, the uterine lining begins to break down. Menstruation begins again.
*The whole cycle repeats.
What happens if fertilisation occurs?
*The fertilised egg becomes a zygote. The zygote develops into an embryo.
*The embryo embeds itself in the uterine lining.
*The embryo secretes a hormone that prevents the corpus luteum from breaking down until a structure called the
placenta is formed.
*The corpus luteum secretes progesterone and oestrogen until the placenta is able to take over hormone production.
What is mating or sexual intercourse?
When a male’s penis is placed inside the vagina of a female, this is known as mating, copulation or sexual intercourse.
How does the embryo develop after fertilisation?
The zygote continues to move slowly towards the uterus. As it proceeds it divides by mitosis. Soon a ball of cells called the embryo forms.
When the embryo reaches the uterus, it sinks into the uterus wall. This is known as Implantation.
(Memorize diagrams in slide 19)
Describe the development of the placenta.
