Lecture 2.2- case 2a sperm
Self-study:
Spermatozoid: male gamete
continuously produced in very large numbers by adult male individuals
(post-puberty).
Oocytes: female gamete
only produce them intermittently (at more or less regular intervals).
Ovarian cycle:
- ovulation: one or more oocytes are released from the ovaries at regular
intervals.
- Oestrus: the period around ovulation and allow mating.
- Oestrous cycle: the period between two ovulations, 4 phases:
1. Prooestrus
2. Oesttus
3. Metoestrus
4. Dioestrus
The prooestrus is the period in which one or more of the largest antral follicles
located in the ovary develop into Graafian follicles. In this period the ovaries are
under the influence of the pituitary hormone FSH.
The oestrus is the period in which the female shows oestrus behaviour and allows
mating and during or shortly after which ovulation of the Graafian follicle(s)
occur, and the released oocyte(s) can be fertilised. Ovulation is caused by the
pituitary hormone LH.
During the metoestrus, the remains of the Graafian follicles luteinize under the
influence of LH, and form corpora lutea that produce progesterone.
The dioestrus is the longest period and is characterized by the presence of
functional corpora lutea in the ovaries. The transition from dioestrus to
prooestrus is characterized by the regression of the corpora lutea; not pregnant.
- Rabbits are an exception, cause the ovulate while mating.
Spermcell production :
Adult male animals of the species that do not have seasonal reproduction have a
continuous semen production or spermatogenesis, which takes place in the
testes, which lay outside of the body in the scrotum. This adjustment is necessary
because the spermatogenesis in these species can only occur at temperatures
lower than body temperature.
If semen production is continuous, spermatogenesis is usually significantly higher
during the breeding season than outside the reproductive season, as for example
in the ram. Spermatogenesis is clearly influenced by day length and seasonal
variation in semen production and quality are clearly present.
Self-study:
Spermatozoid: male gamete
continuously produced in very large numbers by adult male individuals
(post-puberty).
Oocytes: female gamete
only produce them intermittently (at more or less regular intervals).
Ovarian cycle:
- ovulation: one or more oocytes are released from the ovaries at regular
intervals.
- Oestrus: the period around ovulation and allow mating.
- Oestrous cycle: the period between two ovulations, 4 phases:
1. Prooestrus
2. Oesttus
3. Metoestrus
4. Dioestrus
The prooestrus is the period in which one or more of the largest antral follicles
located in the ovary develop into Graafian follicles. In this period the ovaries are
under the influence of the pituitary hormone FSH.
The oestrus is the period in which the female shows oestrus behaviour and allows
mating and during or shortly after which ovulation of the Graafian follicle(s)
occur, and the released oocyte(s) can be fertilised. Ovulation is caused by the
pituitary hormone LH.
During the metoestrus, the remains of the Graafian follicles luteinize under the
influence of LH, and form corpora lutea that produce progesterone.
The dioestrus is the longest period and is characterized by the presence of
functional corpora lutea in the ovaries. The transition from dioestrus to
prooestrus is characterized by the regression of the corpora lutea; not pregnant.
- Rabbits are an exception, cause the ovulate while mating.
Spermcell production :
Adult male animals of the species that do not have seasonal reproduction have a
continuous semen production or spermatogenesis, which takes place in the
testes, which lay outside of the body in the scrotum. This adjustment is necessary
because the spermatogenesis in these species can only occur at temperatures
lower than body temperature.
If semen production is continuous, spermatogenesis is usually significantly higher
during the breeding season than outside the reproductive season, as for example
in the ram. Spermatogenesis is clearly influenced by day length and seasonal
variation in semen production and quality are clearly present.
