Nervous Pathway Eliciting Reproductive Behaviour - Anatomy & Physiology
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- Reproductive behaviour can only take place if the neurons in the hypothalamus have been sensitized to respond to sensory signals.
- Testosterone is aromatized to oestradiol in the brain. Oestradiol promotes reproductive behaviour.
- Testosterone is produced in small episodes every 4-6 hours.
- Relatively constant supply of testosterone, thus oestradiol, to the hypothalamus in the male.
- This allows the male to initiate reproductive behaviour at any time.
- Only experiences high oestradiol during the follicular phase.
- Will only display sexual receptivity during oestrus.
Generic Neural Pathway for Sexual Behaviour
- Under the influence of oestrogen, sensory inputs such as olfaction, audition, vision and tactility send neural messages to the hypothalamus .
- Sensory afferent neurons synapse directly on neurons in the ventromedial and pre-optic hypothalamic regions.
- These sensory inputs cause neurons in the hypothalamus to release behaviour specific peptides that serve as neurotransmitters.
- Neurotransmitters act on neurons in the midbrain.
- Neurons in the midbrain serve as receiving zones for the peptides produced by hypothalamic neurons.
- Midbrain translated neuropeptide signals into a fast response.
- Neurons in the midbrain synapse with neurons in the brain stem (medulla).
- Nervous signals are integrated in the medulla.
- From the medulla, nerve tracts extend to the spinal cord where nerves synapse with motor neurons that innervate muscles that cause lordosis and mounting.