Principles of Animal Physiology


Learning Outcomes

On completion of the module the student should:
● Demonstrate via a written examination an understanding of how key physiological principles underpin animal activity and behaviour
● Have gained experience in designing, executing, interpreting data and writing-up an assessed physiology experiment using an animal model


This module is designed to draw together the fundamental principles underpinning animal physiology via a series of integrated lectures, practical classes, video demonstrations and written assessments.


Physiology is the investigation of the normal functioning of a living organism and its component parts. It is an integrative science, studying how the different organ, tissue and cellular systems co-ordinate in the intact organism. A changing external environment (aquatic or terrestrial) usually presents the greatest problem for animals. This module starts with a review of the central theme in animal physiology, the concept of homeostasis and feedback control i.e. the animal's co-ordinated response to change to maintain internal stability. The lectures clarify other themes that form the basis for investigating animal physiology, such as control, integration of function, metabolism and growth.

Nervous systems have evolved to allow animals to rapidly distinguish important events in their environment, make a decision on the appropriate action, and then to co-ordinate their bodies to carry out these necessary responses. Thus, the first set of lectures in the control section describes the common parts of the animal nervous system (function and organisation, neurons, action potentials and synapses). With this foundation, the major features of sensory physiology (components of a sensation, sensory pathways, receptor classification and neural circuitry) are considered. The next set of lectures explores the relationship between animal glands and secretions (types of secretion, generalized exocrine and endocrine gland structure). The endocrine system of an animal is closely associated with the nervous system, and neurons and hormones often work together to control a single process. Hormones influence behaviour via sensory mechanisms, activity in the central nervous system and effector mechanisms. Therefore, a set of lectures will explore the basis of hormonal activity (structure, mechanism of action, transport and elimination) and the structure and function of key endocrine glands e.g. pituitary, thyroid and adrenals. The final lecture set in this block describes the motor systems that produce adaptive responses. Motor systems consist of motor organ (muscles) and the neural circuits that control them. This lecture starts with a review of movement strategies and, using skeletal muscle as model, describes muscle structure (from gross to molecular level) and the sliding filament mechanism of muscle contraction.

The integration section starts with an assessment of the key elements of the animal circulatory system (basic parts and diversity, the concept of open and closed circulation, structure of the heart, arteries, capillaries and veins) and the concept of cardiovascular control. An understanding of the circulatory system logically allows a consideration of respiration i.e. the basic components of a gas-transfer system, transport of gases in blood, functional anatomy of gas-exchange and function of haemoglobin. The structure and function of lungs, control of respiration and types of breathing are also examined. The next block of lectures reviews the relationship between ionic and osmotic balance (osmosis/osmotic concentration and water/ion budgets) and mechanisms used by invertebrates and vertebrates to respond to change in their environment. The effect of temperature on change on physiological and behavioural processes in animals is also investigated. The lecture course concludes with a study of animal feeding and digestion strategies (classification of feeding mechanism, the structure and function of the generalised digestive system).

The video presentations (key animal physiology experiments) and the practical sessions with living animals (sensory physiology in nematodes and behavioural physiology in beetles) develop the key issues that are raised in the lectures. There are no dissections in this module.