BMS201 - Control of the Internal Environment (10 credits)
Module Co-Ordinator: Dr M. Cambray-Deakin
Aims
This module aims to provide students with an increased knowledge and understanding of the principles of human cardiovascular, respiratory and renal cell biology and physiology, building on the foundations established in Level 1 modules.
Content
The course content is divided into three main blocks covering: heart and circulation (7 lectures), respiratory system (6 lectures), and renal system (3 lectures). The cardiovascular system section deals first with the initiation and conduction of electrical activity evoked during the contraction of the heart and describes how this is generated by the changes in individual cardiac cell membrane potential. Pressure and volume changes in the heart and vasculature throughout the cardiac cycle are covered in detail, as is the microcirculation. Also included are a section regarding the control of the heart and circulation by intrinsic and extrinsic mechanisms, discussion of heart – vessel coupling. The respiration block covers the mechanics of ventilation, examining factors that affect the elastic recoil of the lungs and airway resistance. Ventilation – perfusion relationships are considered.
The generation of rhythmic respiration by the respiratory centres of the brain and its modification by mechanical and chemical reflexes are discussed. The renal lectures will examine three separate topics linked to cardiovascular and respiratory physiology: the glomerulus and its role in the formation of an ultrafiltrate; urine concentration; the roles of blood buffers, respiration and the renal system in acid – base homeostasis. A study of hypertension, to show how renal, respiratory, and cardiovascular systems are involved, concludes the module.
Objectives
In line with the general degree course objectives, on completion of this module students should have enhanced their understanding of the areas of cardiovascular, respiratory and renal physiology and should be able to:
- describe the conduction of electrical activity through the heart and produce annotated diagrams demonstrating the cardiac and pacemaker action potentials.
- describe normal and some abnormal changes in blood pressure and flow that occur throughout the cardiovascular system during the cardiac cycle and relate them to the ECG and valve movements.
- list the intrinsic and extrinsic factors affecting cardiac output.
- explain how circulatory biophysics affect blood pressures and flow.
- describe blood flow through capillaries, tissue fluid production and oedema.
- describe the control of the peripheral circulation by intrinsic and extrinsic factors.
- explain how central nervous system control is involved in governing the cardiovascular system.
- define compliance and explain what it measures.
- explain the significance and special properties of the fluid lining the lungs.
- define airway resistance and describe the mechanical and chemical factors that affect it.
- describe normal regional variations in blood flow and ventilation
- assess the significance of the ventilation – perfusion ratio.
- give an account of the regions of the brain responsible for a normal respiratory pattern.
- give an account of the mechanical reflexes that modify the respiratory rhythm.
- describe the locations of peripheral and central chemoreceptors and the factors that stimulate them.
- describe the forces that regulate the production of a glomerular ultrafiltrate.
- calculate the clearance of a substance.
- describe the transport processes involved in the production of a concentrated urine.
- explain how alterations in body acid – base balance modify the blood, respiratory and renal systems.
Teaching Methods
The module will be taught by traditional 50-minute lectures, with a modular tutorial at the end of the course. The module will be supplemented by a Figures book. Feedback is provided via self-assessment sample questions placed on the module Web page.
Assessment
The module is assessed by a 90 minute combined examination with a multiple - choice, guessing-corrected section and a short-answer or essay section. The multiple choice section should last 60 minutes and will account for 2/3 rds of the final score. The essay/short answer section should last 30 minutes and contribute 1/3 rd to the assessment.