Question

1. Explain the specific contribution of animal models to the study of humans in science in connection with the theory of evolution.

2. A neurotransmitter released into the synaptic space can bind to postsynaptic receptors. List four other possible scenarios following the release of the neurotransmitter into the synaptic cleft.

Answer 1

Animal models are employed in the study of humans because of their similarity to humans in terms of genetics , anatomy and physiology. Also ,animal models are often preferable for experimental disease research , because of unlimited supply and ease of manipulation.

Darwin's description of " descent with modification" points to two aspects of evolution that can help us to assess the matching between a prospective model species and it's intended target.Evolution offers both a rich source of possible models and guidance for choosing the best ones for a given purpose.

Humans and animals share hundreds of illness and consequently animals can be used as models for the study of human illness. Also animals have short life span , so they can be studied throughout their whole lifespan or across several generations.

Scenarios following release of neurotransmitter into synaptic cleft.

• After release into the synaptic cleft , neurotransmitter interacts with receptor proteins on the membrane of the post synaptic cells, causing ionic channels on the membrane to either open or close.
• When these channels open, depolarisation occurs resulting in initiation of action potential.
• Reuptake : neurotransmitters are actively taken back into the neurones that released them.
• If reuptake is blocked , it would result in augmentation of conduction of nerve impulse at those synapse.