Aspects of Human Physiology

• Credit value: 15 credits at Level 5
• Convenor: Dr Richard Rayne
• Assessment: three short-answer tests (10% each), a multiple-choice test (20%) and an end-of-module test (50%)

In this module we will examine fundamental concepts essential to developing a scientific understanding of the functioning of the human. We focus on the functioning of cardiovascular, respiratory and renal systems, with key principles being elucidated across the molecular, cellular, tissue/organ and organismal levels of organisation.

'Systems integration' will be emphasised, so inevitably will also include focused attention on systems of communication (nervous and endocrine) that contribute to the coordinated control of cardiac and smooth muscle, and to the maintenance of body fluid volume and osmolarity.

Indicative syllabus

• Cardiovascular physiology: structure and function of the heart; control of heart rate and force of contraction; the circulatory system
• Respiratory physiology: physical principles of lung function; gas exchange/transport; control of O₂ and CO₂ levels in the blood
• Renal physiology: basic processes of the nephron; control of body fluid composition and osmolarity
• Integration: control of blood pressure and cardiac output

By the end of this module, you will be able to:

• distinguish between flow rate and velocity of flow, and explain the expression Flow α ∆P/R; apply these principles to explain blood flow in the circulatory system and air flow in the lungs
• compare the anatomy and roles of arteries, arterioles, capillaries, venules and veins in the cardiovascular system; explain why velocity of blood flow is fastest in the arteries and slowest in the capillaries
• distinguish between myocardial contractile cells and myocardial autorhythmic cells and, using supplied diagrams, explain the mechanisms by which action potentials are generated in each cell type (including ions, channels and direction of ion movement)
• trace the pathway of electrical conduction through the heart, describing the route from SA node through to excitation of the ventricular contractile cells
• list the events of the cardiac cycle in sequence, beginning with atrial and ventricular diastole; note when valves open and close, and describe what happens to pressure and blood flow in each chamber at each step of the cycle
• review the contrasting effects of the parasympathetic and sympathetic output on heart rate and force of contraction explain briefly how these effects are achieved
• define the terms and consider the major factors influencing the following: cardiac output; stroke volume; heart rate; contractility; end-diastolic volume; mean arterial pressure
• enumerate the factors affecting total oxygen content of arterial blood and explain how the physicochemical properties of haemoglobin ensure it binds oxygen at the lungs and releases oxygen at the tissues
• list the parameters monitored by central and peripheral chemoreceptors monitor for the purpose of regulating ventilation and indicate which of these parameters is most important in normal physiology
• describe mechanisms used by the kidney to accomplish reabsorption of sodium, glucose and water, and, for each substance, indicate the locations within the nephron at which reabsorption occurs
• diagram the appropriate homeostatic compensation for the different combinations of body fluid volume and osmolarity disturbances; map the homeostatic compensation mechanisms for severe dehydration
• consider the homeostatic changes brought about by the baroreceptor reflex acting through the arterioles, the myocardium, and the pacemaker centres of the heart; map these reflex responses for cases of increased blood pressure and for decreased blood pressure.