Session 1: Introduction Flashcards
What are capillaries?
Single layer of endothelial cells surrounded by basal lamina
What type of molecules can diffuse through capillaries?
Lipid soluble molecules - O2, CO2
What are the factors that affect the rate of diffusion? (3)
- Area available for exchange
- Diffusion ‘resistance’ - nature of the molecule, the barrier, the path length
- Concentration gradient
What types of tissues will have a higher capillary density?
More metabolically active tissues
What determines the concentration gradient driving oxygen diffusion into cells?
Rate of blood flow
What is perfusion rate?
Rate of blood flow
Which organs in the body need a high rate of blood flow and when do they need it? (5)
- Brain - constantly
- Heart muscle - constantly, increases with exercise
- Kidneys - constantly
- Skeletal muscle - during exercise
- Gut - after a meal
What is the cardiac output for a 70kg man at rest? (L/min)
5L/min
What is the maximum cardiac output for a 70kg man eg. during exercise?
25L/min
Anatomically, where is the apex of the heart?
Fifth intercostal space, midclavicular line
What is pericardium?
Double-walled sac containing the heart - outer fibrous layer and inner double layer of serous membrane
What dangers does changes to the thin film of fluid in the pericardial cavity pose?
- Excess fluid building up rapidly can compress the heart due to the inextensible fibrous layer
- Compression of the heart can lead to cardiac tamponade
What happens if a major coronary artery gets blocked?
Myocardial infarction
What are the different layers/parts of the pericardium? (6)
- Endocardium
- Myocardium
- Epicardium - visceral layer
- Pericardial cavity
- Parietal layer
- Fibrous layer
