Changes

== Fertilisation, Implantation and Early Embryonic Development ==

== Fertilisation, Implantation and Early Embryonic Development ==

After mating has occured, sperm must [[Copulation -Sperm in the Female Tract - Anatomy & Physiology|travel]] along the female reproductive tract towards the uterus in order to [[Fertilisation, Implantation and Early Embryonic Development -Fertilisation- Anatomy & Physiology|fertilise]] the oocyte. A single spermatazoon penetrates the oocyte and the male and female pronuclei fuse to form an ootid which divides repeatedly to form the [[Fertilisation, Implantation and Early Embryonic Development -Embryonic Development of the Blastocyst- Anatomy & Physiology|blastocyst]]. At this stage the genetic sex of the offspring is determined as male gametes are [[Fertilisation, Implantation and Early Embryonic Development -Sexual Differentiation- Anatomy & Physiology|heterogametic]]. The blastocyst continues to divide and grow until the outer layer, the zona pellucida ruptures and the blastocyst 'hatches' and becomes free floating within the uterus. The blastocyt continues to grow and develop until it becomes an embryo with placntal and embryonic membranes such as the amniotic sac: the placental membranes then attach to the uterine endometrium in a process known as [[Fertilisation, Implantation and Early Embryonic Development -Implantation- Anatomy & Physiology|implantation]]. During embryonic development the process of [[Male Reproductive Tract -Internal and External Genitalia Development - Anatomy & Physiology|sexual differentiation]] begins.

After mating has occured, sperm must [[Copulation -Sperm in the Female Tract - Anatomy & Physiology|travel]] along the female reproductive tract towards the uterus in order to [[Fertilisation, Implantation and Early Embryonic Development -Fertilisation- Anatomy & Physiology|fertilise]] the oocyte. A single spermatazoon penetrates the oocyte and the male and female pronuclei fuse to form an ootid which divides repeatedly to form the [[Fertilisation, Implantation and Early Embryonic Development -Embryonic Development of the Blastocyst- Anatomy & Physiology|blastocyst]]. At this stage the genetic sex of the offspring is determined as male gametes are [[Fertilisation, Implantation and Early Embryonic Development -Sexual Differentiation- Anatomy & Physiology|heterogametic]]. The blastocyst continues to divide and grow until the outer layer, the zona pellucida ruptures and the blastocyst 'hatches' and becomes free floating within the uterus. The blastocyt continues to grow and develop until it becomes an embryo with placntal and embryonic membranes such as the amniotic sac: the placental membranes then attach to the uterine endometrium in a process known as [[Fertilisation, Implantation and Early Embryonic Development -Implantation- Anatomy & Physiology|implantation]]. During embryonic development the process of [[Male Reproductive Tract -Internal and External Genitalia Development - Anatomy & Physiology|sexual differentiation]] begins.

== Gestation ==

== Gestation ==