Tag: pregnancy and birth

Questions Related to pregnancy and birth

Mammalian egg contains negligible yolk so the survival of such embryo is made possible by the fact that they are

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

  1. Nourished through placenta

  2. Too small and need no much food

  3. MiIkfed

  4. None of the above.

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Correct Option: A
Explanation:
All mammals except the monotremes are viviparous. In viviparous animals (such as humans ) the eggs have hardly any food reserve. In these animals, embryo receives nutrients from the mother through a special structure called placenta and remains enclosed in the womb (uterus) until birth. This kind of situation is found in higher mammals (eutherians) and some fishes (sharks). In contrast, eggs of oviparous and ovoviviparous animals contain yolk which is utilized by the developing embryo. The yolk contains all the required nutrients. This kind of situation is found in fishes, amphibians, reptiles, birds and primitive mammals. 

The placenta functions as

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

  1. A protective barrier between mother and embryo

  2. Supply oxygen and nutrients for growth of embryo

  3. Expel the waste matter excreted by the embryo

  4. All of the above

Show answer
Correct Option: D
Explanation:

The placenta is the region which is the main connection between mother and child. It connects the umbilical cord of the developing foetus to the mother's uterine wall to perform several functions. It acts as a barrier between the mother and embryo. It helps in the nutrient uptake, waste elimination, thermoregulation and gas exchange in the foetus through the mother's blood supply. 

Thus, the correct answer is option D. 

Placenta is the region, where

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

  1. Foetus is supplied by maternal blood

  2. Embryo is attached to mother by notocord

  3. Foetus receives maternal blood and nutrition

  4. Embryo is enclosed by membranes

Show answer
Correct Option: C
Explanation:

The placenta is an organ that develops in the uterus during pregnancy. This structure provides oxygen and nutrients to the growing baby and removes waste products from the baby's blood. The placenta attaches to the wall of the uterus, and the baby's umbilical cord arises from it. In most pregnancies, the placenta attaches to the top or side of the uterus. 

Therefore, the correct answer is option C.

Which substance normally passes from a fetus to its mother through the placenta?

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

  1. Alcohol

  2. Glucose

  3. Oxygen

  4. Urea

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Correct Option: D
Explanation:

The placenta is an organ responsible for providing oxygen and nutrients to the fetus from the mother, and removing waste substances like urea from the fetus to the mother.

Pick the mammal with true placenta.

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

  1. Kangaroo

  2. Echidna

  3. Platypus

  4. Mongoose

Show answer
Correct Option: D
Explanation:

The mammals that show the presence of a placenta is called placental mammals. They are also called eutherians. Mongoose is a placental mammal. The placenta is the connection between the developing fetus to the mother's uterine wall. The placenta performs several functions such as nutrient uptake, waste elimination and gaseous exchange in the fetus through the mother's blood supply. Thus the correct answer is option D.

Which of the following structure is lacking from the placenta?

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

  1. Arteries

  2. Veins

  3. Smooth muscles

  4. Nerves

Show answer
Correct Option: D
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'.

Which one of the following develops from the trophoblast?

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

  1. Placenta

  2. Allantois

  3. Epidermis of the skin

  4. Yolk sac

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Correct Option: A
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'.

Foetus is nourished by

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

  1. Placenta

  2. Yolk

  3. Sertoli cells

  4. Phagocytosis

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Correct Option: A
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.

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

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

  1. One

  2. Two

  3. Three

  4. Four

Show answer
Correct Option: C
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.'

Attachment of foetus of placenta occurs through

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

  1. Chorda mesoderm

  2. Spinal cord

  3. Umbilical cord

  4. Notochord

Show answer
Correct Option: C
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'