[4] Mammalian spermatogenesis

The ___ and ___ are exactly alike in both animals.

tunica albuginea; seminiferous tubules

the testis of rats have no ___ and the cells are orderly arranged such that the youngest cells are found near the ___ and the oldest ones are found towards the ___ of the tubules. Such arrangement of cells is known as ___. Roughly, it forms a ___ group of cells within the tubule

spermatocysts; basement membrane; center or lumen; Cell Association; triangular

Each segment of the seminiferous tubule is in one stage of the cycle and the next stage is in the tubular segment adjacent to it. Hence, there is a sequential order of stages along the entire length of the tubule. This is called the ___

wave of seminiferous tubule

There are ___ cell associations or stages of a cycle in rats and only ___ in human. All the stages of a cycle, thus, can be observed in one section of the testis.

14; six

the same types as those of the frog’s testis but are concentrically arranged from the periphery to the center of the tubule according to their stage of development

spermatogenic cells

nonspermatogenic cells

somatic cells

what are the somatic cells

• sertoli cells

• leydig cells

large cells with distinct nucleoli located inside the seminiferous tubules. They may be seen lying parallel to the basement membrane or its apical end towards the lumen

sertoli cells

a cluster of three to five large cells found in between the seminiferous tubules. They have a clear cytoplasm and nuclei. Blood vessels and nerves may be seen adjacent to them.

leydig cells

section through part of an adult rat testis

section through part of a rat testis showing seminiferous tubules

section through part of a rat testis showing seminiferous tubules

transverse section of a rat seminiferous tubule

transverse section of a rat seminiferous tubule

transverse section of a rat seminiferous tubule

transverse section of a rat seminiferous tubule

transverse section of a rat seminiferous tubule

transverse section of a rat seminiferous tubule

transverse section of a rat seminiferous tubule

The union of a haploid secondary oocyte (ovum) with a haploid spermatozoon to form a diploid zygote

fertilization

fertilization takes place in the ____

fallopian tube

_____ is a single cell capable of developing into a new individual of the species

zygote

fertilization begins with ___ (zygote formation) and ends with the initiation of ___ (start of cleavage)

gamete fusion; zygote mitosis

fertilization: 1. the sperm approaches the ___-

egg

fertilization: 2. the sperm’s ____ digest the egg’s _____

acrosomal enzymes; jelly coat

fertilization: 3. proteins on the ___ bind to receptors

sperm head

fertilization: 4. the ___ of the sperm and egg fuse

plasma membrane

fertilization: 5. the sperm nucleus enters the ____

egg cytoplasm

fertilization: 6. a ____ forms

fertilization membrane

fertilization: 7. the ___ of the sperm and egg fuse

nuclei

In mammals, Sex is determined by the sex chromosome of the ___ that fertilizes the ovum

spermatozoan

sex determination in mammals:

• Ova (X) + Sperm (Y) - ___ Offspring (XY)

• Ova (X) + Sperm (X) - ___ Offspring (XX)

Male; Female

In birds, sex is determined by the sex chromosome of the ____

ovum

sex determination in birds:

• Ova (Z) + Sperm (Z) = ___ Offspring (ZZ)

• Ova (S) + Sperm (Z) = ___ Offspring (ZS)

Male; Female