Tag: zoology

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Questions Related to zoology

Multiple choice zoology reproduction in humans placenta pregnancy and birth fertilization and post fertilization in humans

Which of the following structure is lacking from the placenta?

  1. Arteries

  2. Veins

  3. Smooth muscles

  4. Nerves
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The placenta is an organ, that connects the fetus to the uterine wall. This allows the nutrient uptake, waste elimination and gas exchange via the mother's blood supply, fights against internal infection and produces hormones to support pregnancy. Placenta connects the fetus by an umbilical cord which contains two umbilical arteries and one umbilical vein. The placenta is encircled by a ring of smooth muscle cells.
The placenta does not have nerves.
Thus, the correct answer is option (D), 'Nerves'.

Multiple choice zoology reproduction in humans placenta pregnancy and birth fertilization and post fertilization in humans

Which one of the following develops from the trophoblast?

  1. Placenta

  2. Allantois

  3. Epidermis of the skin

  4. Yolk sac
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Trophoblasts are the cells forming the outer layer of a blastocyst, which provides nutrients to the developing embryo and it develops into a large part of placenta. Thus, trophoblasts are specialized cells of the placenta that plays an important role in embryo implantation.
Thus, the correct answer is option (A), 'Placenta'.

Multiple choice zoology reproduction in humans placenta pregnancy and birth fertilization and post fertilization in humans

Foetus is nourished by

  1. Placenta

  2. Yolk

  3. Sertoli cells

  4. Phagocytosis
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A placenta is formed from interdigitation of the trophoblast layer of the embryo and the endometrial lining during implantation. It facilitates the supply of oxygen and nutrients to the developing foetus and is also responsible for removal of carbon dioxide and excretory waste products of the foetus.

Yolk sac along with the allantois layer forms the umbilical cord, the connection between the embryo and the placenta.
Phagocytosis is the ingestion of bacteria and other foreign agents by the defence system of the body.  So the correct answer is A.

Multiple choice zoology reproduction in humans placenta pregnancy and birth fertilization and post fertilization in humans

In simplest type of placenta, six barriers separate maternal blood from foetal blood. How many barriers are lost in human placenta?

  1. One

  2. Two

  3. Three

  4. Four
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
In human placenta, the barriers include uterine epithelium, uterine connective tissue and endothelium of maternal blood vessels are absent.
So the correct option is 'Three.'
Multiple choice zoology reproduction in humans placenta pregnancy and birth fertilization and post fertilization in humans

Attachment of foetus of placenta occurs through

  1. Chorda mesoderm

  2. Spinal cord

  3. Umbilical cord

  4. Notochord
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In humans, the placenta is chorionic in nature. It attaches the foetus and the mother and is responsible for the nutrition and excretion and exchange of gases.

The umbilical cord is a tube-like structure that connects the foetus and mothers placenta. The belly button is the entry point of the umbilical cord in the foetus. The umbilical cord contains arteries and veins and is protected by a jelly-like substance known as the Wharton's jelly.
So, the correct option is 'Umbilical cord' 

Multiple choice zoology reproduction in humans placenta pregnancy and birth fertilization and post fertilization in humans

Extra structure which provides nutrition to embryo is

  1. Umbilicus

  2. Chorion

  3. Placenta

  4. Amnion
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

After implantation, finger-like projections appear on the trophoblast called chorionic Villi which are surrounded by uterine tissue and maternal blood. The chronic villi and uterine tissue become interdigitated with each other and jointly form a structural and functional unit between developing embryo that is foetus and maternal body called placenta. Placenta facilitate the supply of oxygen and nutrients to the embryo and also helps in removal of carbon dioxide in excretory waste materials produced by the embryo.

 So, the correct option is 'Placenta'.

Multiple choice zoology reproduction in humans placenta pregnancy and birth fertilization and post fertilization in humans

Which one is not a character of haemochorial placenta?

  1. $CO _2$ and excretory products pass from foetus to mother's body.
  2. $O _2$ and nutrients from mother's body enter the foetus.

  3. Chorion villi are covered by blood sinuses of mother.

  4. It protects foetus from mechanical shocks.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The haemochorial placenta is the type of placenta in which maternal blood is in direct contact with the chorionic villi which are covered by maternal blood and exchange of gases and nutrients from mother's blood and foetus takes place as observed in humans.

So the correct option is 'It protects foetus from mechanical shocks'

Multiple choice zoology reproduction in humans placenta pregnancy and birth fertilization and post fertilization in humans

Which is not correct about placenta?

  1. It prevents passage of maternal IgG to foetus.

  2. It acts as foetal lung.

  3. It acts as foetal liver.

  4. It acts as endocrine gland.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The placenta is a cushion-like tissue which facilitates the supply of oxygen and nutrients to the embryo and also the removal of carbon dioxide and excretory waste materials produced by the embryo. It also acts as an endocrine tissue and produces several hormones such as human chorionic gonadotropin, human placental lactogen, estrogens, progesterone and relaxin during pregnancy.
So, the correct option is 'It prevents passage of maternal IgG to the foetus'.
Multiple choice zoology reproduction in humans placenta pregnancy and birth fertilization and post fertilization in humans

Which of the following is not the function of placenta?

  1. Secretes oxytocin during parturition
  2. Facilitates supply of $O _2$ and nutrients to embryo

  3. Secretes estrogen
  4. Facilitates removal of $CO _2$ and waste products from embryo
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The placenta is a cushion-like tissue which facilitates the supply of oxygen and nutrients to an embryo and also the removal of carbon dioxide and excretory waste materials produced by the embryo. It also acts as an endocrine tissue and produces several hormones such as human chorionic gonadotropin, human placental lactogen, estrogens, progesterone and relaxin.
So, the correct option is 'Secretes oxytocin during parturition'.