Chapter 7 Flashcards
Tidal volume
Volume of air moving in and out during each breath
Minute volume
Tidal volume x respiratory rate = minute volume
Amount of air moved in and out of lungs in one minute.
Interference with the minute volume results in respiratory dysfunction.
Hypoxia
Low oxygen levels
Hypercapnia
High carbon dioxide levels
What detects changing oxygen and carbon dioxide levels?
Chemoreceptors
Plasma oncotic pressure
Proteins in the plasma attract water into bloodstream. Increases the blood pressure.
Hydrostatic pressure
Water pushed back out of blood vessels toward cells. Decreases the blood pressure.
Blood vessel dysfunction: loss of tone
Blood pressure is controlled by changing the diameter of blood vessels
Vessels lose ability to constrict and dilate properly
Dilated vessels with reduced blood volume results in a pressure drop. At an extreme, it can result in loss of tone.
Hypertension
Systemic vascular resistance (SVR) is the resistance in the circulatory system that is used to create blood pressure.
Hypertension is high blood pressure.
Stroke volume
Volume of blood pumped out of the left ventricle of the heart during each contraction.
Output of blood is based on preload, contractility, and afterload
What is the average stroke volume?
~70 mL blood per contraction
Cardiac output
Stroke volume x beats per minute = cardiac output
Very fast heart rates reduce cardiac output. There is not enough time for the heart to refill between contractions.
Pediatric compensation
- Rely on heart rate to compensate for poor perfusion
- Lack contractile muscles
- Cannot regulate the force of contraction
- Fast heart rate indicates compensation
4 Categories of shock
Hypovolemic = low blood volume
Distributive = low blood vessel tone
Cardiogenic = heart fails to pump
Obstructive = blood cannot flow
Distribution of water in the body
Body is 60% water
- 70% Intracellular
- 5% Intravascular
- 25% Interstitial
