Session 1 Flashcards
What is diffusion resistance dependent on?
The path length (which is dependent on capillary density)
What is diffusion affected by?
The capillary density
Diffusion resistance
Concentration gradient
How do lipid soluble and hydrophilic molecules pass through capillary walls?
Lipid soluble - pass through the cell membrane of the endothelium
Hydrophilic - pass through pores
What does the concentration gradient depend on?
The flow of blood through capillaries
The concentration of nutrients in the blood
What is the blood flow required by the brain?
750 ml/min
Why is capacitance important?
Allows the circulation to withstand changes in cardiac output. Can store blood in the veins.
Where is the heart located?
In the middle mediastinum in the thoracic cavity
What are the two layers of the pericardium?
The fibrous and the serous
What are the layers of the serous pericardium?
The parietal (outer) and visceral (inner)
What is the serous pericardium mainly composed of?
Mesothelium
How is the pericardium secured?
Attached anteriorly to the sternum by ligaments
Continuous inferiorly with the central tendon of the diaphragm
Bound posteriorly by loose connective tissue to structures in the posterior mediastinum
What are the functions of the pericardium?
Fixes the heart in the mediastinum and limits its motion
Prevents overfilling of the heart by preventing the heart from increasing in size due to its fibrous layer
Lubrication reduces friction
Protection from infection
What is the nerve supply to the pericardium (and the diaphragm)?
The phrenic nerves (C3, C4, C5)
How might pericarditis present?
Chest pain
Rustling through a stethoscope
