Chapter 15 - Reproduction in Humans Flashcards
(39 cards)
What is the Cervix?
Ring of muscle that dilates to allow the baby to be born
What is the function of the Ovary?
Produces egg cells
Secretes female sex hormones ( Oestrogen and Progesterone )
What is the Oviduct?
Site of fertilisation
What is the Uterus?
Site of implantation
What is the Vagina?
Where sperm are deposited during intercourse
What are the 2 female sex hormones?
Oestrogen and Progesterone
What is ovulation?
14th day of menstrual cycle when the ovary releases an egg cell
What is the function of the Penis?
Delivers sperm into the vagina
What is the function of the prostate gland?
Makes the fluid that sperm cells swim in
What is the function of the scrotum?
Holds the testes and keeps them cool
What is the function of the sperm duct?
Carries sperm away from the testes
What is the function of the testis?
Produces sperm and secretes male sex hormone ( testosterone )
What is the structure of a sperm cell from head to tail? Give a description of each part
Acrosome, enzymes in the acrosome break down the jelly coat of the egg
Haploid Nucleus
Middle Piece, contains mitochondria for respiration to provide energy for movement
Flagellum, used for movement
What is the structure of an egg cell? Give a description of each part
Jelly coat, becomes hard at fertilisation to prevent multiple fetilisations by other sperm entering the egg cell
Energy Stores, contain glycogen and lipids and are in the cytoplasm for early embryo development
Describe what happens at fertilisation
The sperm release enzymes made in the acrosome to digest the jelly coat so the sperm nucleus can enter the egg cell
The fertilisation membrane forms (or the egg membrane becomes impermeable) so no more sperm can enter
The sperm’s and the egg cell’s haploid nuclei fuse to form a diploid zygote (called fertilisation)
The jelly coat of the fertilised egg cell hardens to prevent multiple fertilisations
Describe what happens after fertilisation
The zygote divides by mitosis to form a ball of genetically identical cells called an embryo
The embryo travels to the uterus by peristalsis and ciliary action into the oviduct.
The ovary (or corpus luteum) continually releases progesterone to maintain the uterus lining thickness
The embryo implants into the uterus lining (this is known as implantation)
The development of the placenta also begins
After 3 months, the embryo will develop into a foetus, and the corpus luteum will also break down
The placenta will begin to release progesterone, due to the breakdown of the corpus luteum
What are the functions of Oestrogen and Progesterone?
Oestrogen repairs the uterus lining
Progesterone maintains the thickness of the uterus lining
What is the difference between an embryo and a foetus?
Embryo is a hollow ball of genetically identical cells
Foetus is an embryo which has developed and started to grow organs such as the eyes, heart and limbs
What is the difference between growth and development?
Growth refers to the increase in the number of cells and dry biomass
Development refers to the increase in complexity of an organism
Describe foetal development
Foetal development concentrates on increasing complexity (cells differentiate) in the early stages of pregnancy and increasing in size towards the end of pregnancy.
Which 4 factors affect the rate of diffusion across the placenta?
Higher temperature
Steeper concentration gradient
Larger surface area
Shorter diffusion distance
What is the function of the Amniotic sac?
Secretes and encloses the amniotic fluid
What is the function of the Amniotic fluid?
Protects the foetus from physical shock
Maintains a constant temperature and pressure
Protects the foetus from dehydration
Allows the foetus to move
Lubricates the cervix and vagina during birth
What is the function of the Umbilical cord?
The umbilical vein carries oxygenated blood to the foetus
The umbilical artery carries deoxygenated blood away from the foetus
