Answer the following questions from your knowledge of human embryology - Leaving Cert Biology - Question c - 2004
Question c
Answer the following questions from your knowledge of human embryology.
(i) What is a germ layer? List the three germ layers.
(ii) Relate each of the germ layers t... show full transcript
Worked Solution & Example Answer:Answer the following questions from your knowledge of human embryology - Leaving Cert Biology - Question c - 2004
Step 1
What is a germ layer? List the three germ layers.
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Answer
A germ layer is a layer of cells in the blastula (embryo) that has the potential to give rise to specific tissues or organs in the developing organism. The three germ layers are:
Ectoderm
Endoderm
Mesoderm
Step 2
Relate each of the germ layers that you have listed in (i) to an organ or system in the adult body.
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Answer
Ectoderm: Develops into structures such as skin, hair, nails, and the nervous system.
Endoderm: Forms the inner lining of the gut and gives rise to organs such as the liver and pancreas.
Mesoderm: Gives rise to muscles, the skeleton, and systems like the excretory system, respiratory system, and circulatory system.
Step 3
From what structures does the placenta develop? State three functions of the placenta.
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Answer
The placenta develops from structures including the uterine tissue and embryonic tissue.
Three functions of the placenta are:
It produces hormones to support pregnancy.
It allows the passage of nutrients and oxygen from the mother to the fetus while removing waste products.
It acts as a barrier to protect the fetus from harmful substances.
Step 4
Name a hormone associated with the maintenance of the placenta.
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The hormone associated with the maintenance of the placenta is Progesterone.
Step 5
Describe the amnion and state its role.
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Answer
The amnion is a sac or membrane that surrounds the embryo in the amniotic cavity. Its role is to hold amniotic fluid, which protects the embryo or fetus by cushioning it from physical shocks and maintaining a stable temperature.
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