EXPLAIN THE TERM IN VITRO FERTILISATION
Involves removing eggs from the ovary and fertilising them outside the body.
SUGGEST A REASON FOR THE REMOVAL OF SEVERAL EGGS
A number of eggs are removed to increase the chances of fertilisation occurring and getting an embryo to implant.
IDENTIFY A GERM LAYER FROM WHICH THE SKIN OF THE DEVELOPING EMBRYO ARISES ?
Ectoderm
FROM WHICH TISSUES DOES THE PLACENTA FROM
The placenta is formed from the chorion (the outer membrane of the embryo) and the mother’s blood vessels.
EXPLAIN WHY MIXING MUST NOT OCCUR
Blood groups may be different types, if their bloods mix, an immune response would be triggered
Mother’s blood pressure may harm the embryo as it is too high.
FUNCTIONS OF THE PLACENTA
The placenta allows substances to be exchanged between mother and embryo, e.g. gases, nutrients, antibodies, etc.
The placenta also produces progesterone.
STATE ONE CHANGE THAT OCCURS AND APPROXIMATE DAYS OF THE CYCLE ON WHICH IT OCCURS
- Days 1-5: The endometrium breaks down.
- Day 14: The Graafian follicle bursts releasing the egg from the ovary.
WHERE ARE THE HORMONES LH AND FSH PRODUCED
Pituitary gland
STATE ON ROLE OF EACH
Role of FSH: It stimulates the egg to develop.
Role of LH: It causes ovulation.
NAME 2 OTHER HORMONES
Progesterone: produced by the corpus luteum ensures the endometrium remains in place (in case the egg is fertilised).
Oestrogen: Causes growth of the endometrium, stimulates LH
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DRAW DIAGRAM OF MALE REPRODUCTIVE SYSTEM
DRAW X WHERE MEIOSIS OCCURS
SUGGEST WHY SPERM CELL NEED SO MANY MITOCHONDRIA
Mitochondrion are the site of respiration and so produce energy in respiration. The sperm need a lot of energy to swim to the egg.
EXPLAIN WHY MITOCHONDRIA ARE EXCLUSIVELY INHERITED FROM THE MOTHER
It is just the chromosomes in the nucleus that are inherited from both parents. The cell organelle must come from the egg.
STATE SURVIVAL TIMES OF EGG AND SPERM IN THE FEMALE BODY
Egg 0 - 48 hours
Sperm 3 days/72hours
GIVE ONE FUNCTION OF A NAMED GLAND
The prostate gland (with the seminal vesicles and Cowper's gland) produces seminal fluid, which provides a medium for sperm to swim and also provides a food source for the sperm.
WHAT IT IS THE NEXT DEVELOPMENTAL STAGE AFTER THE MORULA
Blastocyst
GIVE ONE CHANGE EXPERIENCED BY THE MOTHER INDICATING THE BIRTH PROCESS IS STARTING
Contractions/ amnion breaks releasing the amniotic fluid
GIVE A SHORT ACCOUNT OF THE BIRTH PROCESS
Stage 1
Contractions on the uterus push foetus towards the cervix
Cervix dilates
amnion break releasing
Amniotic fluid
Stage 2
Foetus passes through the cervix and birth canal head first
Baby is delivered
Umbilical cord is tied and cut
Stage 3
Uterus contracts again and expels after birth (umbilical cord and placenta)
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NAME THE 3 GERM LAYERS
Ectoderm, mesoderm and endoderm
FOR EACH DERM NAME A STRUCTURE IN THE ADULT BODY THAT DEVELOPS IT
ectoderm- nervous system, mesoderm - skeletal system, endoderm- digestive system
FROM WHAT TISSUES DOES THE EMBRYO DEVELOP
Embryonic
WHAT IS AN AMNION
A membrane (sac) that surrounds the embryo
EXPLAIN THE IMPORTANCE OF AN AMNION FOR A FOETUS
Protects the embryo
WHAT IS SEMEN
Seminal fluid and sperm
NAME A FEMALE MENSTRUAL DISORDER
Fibroids
Cause: unknown. OEstrogen and progesterone are the hormones produced by the ovaries. They cause the uterine lining to regenerate during each menstrual cycle and may stimulate the growth of fibroids
Treatment: radiation or surgically removed
MORULA: Solid ball of cells
BLASTOCYST: Fluid filled or hollow ball of cells
2 BIOLOGICAL ADVANTAGES OF BREASTFEEDING
Ideal balance of nutrients for baby
Contains essential antibodies protecting the baby against infection