The document discusses morula in humans. It states that a morula: - Has almost equal quantity of cytoplasm as an uncleaved zygote but much more DNA. - Is an early stage embryo consisting of cells in a solid ball within the zona pellucida, produced through rapid division of the zygote. - Undergoes divisions rapidly because there is no growth, so cell number increases while size decreases, resulting in almost equal cytoplasm but more DNA compared to an uncleaved zygote.

1. practice question-Most Important
practice question-Previous Year
Which one of the following statements about morula in humans is correct ?
A
It has almost equal quantity of cytoplasm as an uncleaved zygote but much more DNA
B
It has more or less equal quantity of cytoplasm and DNA as in uncleaved zygote
C
It has far less cytoplasm as well as less DNA than in an uncleaved zygote
D
It has more cytoplasm and more DNA than an uncleaved zygote
Explanation
A morula is an embryo at an early stage of embryonic development, consisting of cells
(called blastomers) in a solid ball contained within the zona pellucida. The morula is
produced by embryonic cleavage, the rapid division of the zygote. The increase in
number of cells doesn't change the size of the original mass. The divisions are rapid
because there is no net growth of the embryo-the cell cycle alternates between DNA
replication and mitosis. In the absence of growth, the cell number in the embryo
increases while the cell size decreases. Thus, it has almost equal quantity of cytoplasm
as an uncleaved zygote but much more DNA.
Key Concepts

2. Seminiferous tubules are found in
A
Lung
B
Testis
C
Ovary
D
Kidney
Explanation
Each testicular lobules of testis contains two to three seminiferous tubules. Wall of each
seminiferous tubules is formed of a single layered germinal epithelium.
Key Concepts
Testis
Primary Concept
arrow icon

3. Testes in rabbit are
A
On either side of dorsal aorta
B
On the sides of the kidneys
C
Inside the body
D
In scrotal sacs
Explanation
In most of the mammals, testes are extra-abdominal as spermatogenesis requires a
lower temperature for its normal completion.
Key Concepts
Testis
Primary Concept
arrow icon

4. In mammals, failure of testis to descend into the scrotum is known is.
A
Paedogenesis
B
Impotency
C
Cryptorchidism
D
Castration
Explanation
Cryptorchidism is the failure of one or both of the testicles to descend into the scrotum.
Key Concepts
Testis

5. The abdominal passage which connects the abdominal cavity with the scrotal sac in
mammals is known as
A
Inguinal canal
B
Spermatic canal
C
Haversion canal D
Neurenteric canal
Explanation
Through this testes descend into scrotal sacs.
Key Concepts
Testis

6. practice question-tagMost Important
Which of the following is correct about mammalian testes.
A
Graafian follicle, Leyding cell, seminiferous tubules.
B
Graafian follicles, Sertoli cells, Leydig cells.
C
Graafian follicles, Sertoli cells, seminiferous tubules.
D-Sertoli cells, seminiferous tubules, Leydig cells.
Explanation
Graafian follicles are present in human ovaries. Sertoli cells, seminiferous tubules, Leydig cells
are present in human testes.

7. The Nutritive cells found in seminiferous tubules
are
A
Leydig's cell
B
Spermatogonial cells
C
Atretic folicular cells
D
Sertoli cellsExplanation
The tests are formed of numerous tubular seminiferous tubules. Each seminiferous tubule
shows an orderly arrangement of cells undergoing different phases of maturation. The
peripheral layer of cells next to the basement membrane is formed of spermatogonia or sperm
mother cells and is often described as germinal epithelium. In between the group of
spermatogonia are tall columnar cells, the Sertoli cells that provide nourishment of developing
sperm.
Key Concepts
Sertoli / Nurse Cell
Examples on Sertoli / Nurse Cell

8. Where do sperms mature and become
motile?
A
Epididymis
B
Leydig cells
C
Urethral meatus D None of these
Explanation
Vas deference is a tubular structure continuous with the epididymis. It enters the adominal cavity
and joins the seminal vesicle. The mature spermatozoa from epididymis pars in to vas deferens.
Here they partly swim and are mainly moved by muscular action of the vas deferens.
Key Concepts
Epididymis