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Michaelmas Term lectures

Introduction; the Mammalian Cardiovascular System: Dr James Fraser (5 lectures)

The course will comprise five lectures on the cardiovascular system and its control. Topics to be covered will include the particular contributions of cardiac output and total peripheral vascular resistance in the control of arterial blood pressure, the role of peripheral baroreceptors and chemoreceptors in the control of arterial blood pressure and the distribution of the cardiac output. We will consider the central nervous system and its role in the regulation of the circulation. We will discuss the control of blood flow and formation of tissue fluid in all tissues of the body and focus on blood flow to the vital tissues and the skeletal muscular system. We will then consider the cardiovascular responses to exercise as an example of an integrated cardiovascular response to a powerful physiological challenge. We will also talk about the circulatory responses to hypoxia, which are much more interesting than the responses to changes in blood pressure, or the responses to haemorrhage (which we will briefly review).

Clinical Cardiovascular Physiology: Dr James Fraser (1 lecture)

Respiration: Dr Mike Mason (7 lectures)

Our ability to maintain optimum partial pressures of oxygen and carbon dioxide in arterial blood is dependent upon the appropriate matching of alveolar ventilation and blood perfusion of the lung. In this lecture block I will demonstrate how the elastic properties of the lung and chest wall influence alveolar ventilation. I will also detail how the characteristics of the pulmonary circulation and the influence of gravity interact to control pulmonary blood flow. Finally, I will demonstrate how regional differences in alveolar ventilation and blood perfusion of the lung interact in a somewhat curious fashion.

We will begin by conducting a review the of the key structure and function of the mammalian lung that brings about equilibration of the alveolar gases with the pulmonary venous blood. This lecture will act as a review of key concepts of the mammalian respiratory system introduced in IA Physiology of Organisms.

I will introduce the concepts of elasticity and compliance of the lung and chest wall and detail the determinants of elasticity in the respiratory system. The influences of regional lung compliance upon regional alveolar ventilation will be presented.

I will discuss the characteristics of the pulmonary circulation with particular emphasis on how the pulmonary circulation differs from the systemic circulation. In this lecture we will investigate how gravity influences regional blood flow in the lung.

I will discuss the implications of the differences in the profile of lung ventilation and lung blood perfusion and introduce the concept of the ventilation-perfusion ratio.

To end the lecture series we will look at the respiratory system under stress, highlighting the impact that altitute, hyperbaric breathing and exercise have on our ability to maintain respiratory homeostasis.

Endocrinology: Dr Matt Mason (3 lectures)

This short lecture course looks at some of the important hormones in the body that were not considered in IA Physiology of Organisms. Human physiology is emphasised, but illustrative examples based on other animals will be given throughout.

Lecture 1: Calcium Homeostasis
We shall consider the hormonal regulation of calcium ion concentration in the plasma. You will learn why it is vital to respond rapidly to challenges to calcium metabolism, and we shall look at examples of such challenges. You will see how parathyroid hormone has both short-term and long-term effects (some via vitamin D derivatives) on the bone, the kidneys and the intestines. You will also learn about the enigmatic role of calcitonin.

Lecture 2: The Pituitary Gland and Growth Hormone
We shall consider the structure, function and principles of control of the anterior pituitary gland. You will be introduced to two of the three families of anterior pituitary hormones. You will learn about the two contrasting roles of growth hormone, in growth and in fasting, and you will examine how growth is driven (in times of nutritional plenty) by insulin-related growth factors.

Lecture 3: The Hypothalamic-Pituitary-Adrenal Axis
We shall look at the POMC family of pituitary hormones, concentrating on MSH and ACTH. We will consider the factors tha control the release of ACTH from the anterior pituitary, and its actions on the adrenal cortex. You will look at the structure and functions of the adrenal gland, and the roles of the steroid hormones secreted from the adrenal cortex. We shall concentrate on cortisol, looking both at its glucocorticoid functions and several other actions of this hormone on the body. We will discuss the various roles of cortisol in coping with different kinds of stresses.

Human Renal Physiology: Dr Stewart Sage (5 lectures)

These lectures will explore renal function at the organ and cellular level. They will then examine how these activities are regulated by nerves, hormones and intrinsic mechanisms in order to achieve body fluid homeostasis. The regulation of extracellular Fluid volume will be looked at in detail, and the regulation of the concentrations of certain ions and other molecules will be examined.

Lecture 1. Introduction and overview of kidney function. The principle of balance. Body water and fluid compartments. Measuring compartment volumes by the dilution technique. Brief reminders of kidney structure, the renal tubule and renal vasculature. Recap of basic renal mechanisms. Glomerular filtration.

Lecture 2. Filtration pressures. Equilibrium and non-equilibrium filtration. Glomerular filtration rate. Evidence for urine formation by filtration rather than secretion. Autoregulation of renal blood flow and GFR. Overview of tubular reabsorption and secretion. Clearance. Measuring GFR and renal plasma flow using clearance and the Fick method. Tubular transport mechanisms. Reabsorption of glucose, amino acids and proteins. Secretion of organic ions.

Lecture 3. Brief reminder of water handling by the kidney and of osmoregulation. Evidence for the current models. Regulation of extracellular fluid volume. Sodium homeostasis. Physical factors influencing sodium excretion. Nervous and hormonal factors influencing sodium excretion.

Lecture 4. The renin-angiotensin system. Aldosterone. Atrial Natriuretic Peptide. Examples of volume regulation, osmoregulation and their interaction.

Lecture 5. Renal aspects of calcium homeostasis. Tubular calcium handling and its hormonal regulation. Potassium homeostasis. Hyperkalaemia and hypokalaemia. Excretion of potassium by the kidney and its regulation. Role of aldosterone in potassium excretion.

The Physiology of Blood and Lymph: Dr Milka Sarris (One lecture)

Physiology of pH Regulation: Dr Stewart Sage (Two lectures)

Lecture 1. Definition of pH. Buffering and the Henderson-Hasselbalch equation. Extra cellular fluid buffers. Roles of lungs, kidneys and liver in pH regulation.

Lecture 2. Transport of protons, ammonium and bicarbonate by the renal tubules. Acidosis and alkalosis. Examples of pH challenges and responses to them.

 Animal Models in Physiology: Prof. Jenny Morton (One lecture)