Lecture 26. Fundamentals of Cardiovascular and Respiratory Physiology Part 1. Flashcards
What is the cardiac cycle ?
The contraction and relaxation of the heart in a rhythmic cycle
What is another word for the contraction of the heart ?
Systole
What is another word for the relaxation of the heart ?
Diastole
What is the flow of blood through the heart known as ?
Unidirectional
What is backflow of blood prevented by ?
AV and semilunar valves
What makes the lub dub heart sound ?
Valve closure
What is the cardiac output ?
Volume of blood pumped by each ventricle each minute
What regulates cardiac function ?
Autonomic nervous system
What does the parasympathetic division of the autonomic nervous system do to the cardiac function ?
Innervates the SA node which slows the heart rate
What does the sympathetic division of the autonomic nervous system do in cardiac function ?
Innervates the SA node which increase heart rate
How does exercise effect autonomic nervous system function ?
Decreases parasympathetic activity and increases sympathetic activity
What is gas exchange ?
The uptake of oxygen from the environment and the discharge of carbon dioxide to the environment
What is boyle’s law ?
At constant temperature, pressure and volume are inversely related
What biological process is Boyle’s law a part of ?
Breathing
What is spirometry ?
Method of measuring lung function
What is the gas composition of air ?
- 79% nitrogen
- 21% oxygen
- Trace amounts of carbon dioxide, helium, argon etc.
What do gasses diffuse down ?
Pressure gradients (High pressure to low pressure)
What is partial pressure ?
The pressure exerted by a particular gas in a mixture of gases
In gas mixtures, what do gases diffuse down ?
Partial pressure gradients (High partial pressure to low partial pressure)
How is heart beat initiated by autorhythmic activity ?
- Signals from SA node spread through atria
- Signals are delayed at AV node
- Bundle branches pass signals to heart apex
- Signals spread throughout ventricle
What is heart rate and contractile strength modulated by ?
Autonomic nervous system
What is tachycardia ?
Abnormally fast heart rate
What is bradycardia ?
Abnormally slow heart rate
What is fibrillation ?
Loss of coordination of electrical activity. Can be corrected by defibrillation
What does atrial fibrillation result in ?
Weakness
What does ventricular fibrillation result in ?
Death in minutes, damage to heart muscle
What is haemodynamics ?
How blood moves through the circulation
What is the process of gas exchange ?
- Inhaled air
- Alveolar spaces
- Pulmonary veins and systemic arteries
- Body tissue
- Pulmonary arteries and systemic veins
- Exhaled air
Where is oxygen not very soluble ?
Plasma
Where is haemoglobin present ?
In erythrocytes
How many molecules of oxygen can haemoglobin bind ?
4
Where does carbon dioxide from respiring cells go ?
- Diffuses into the blood and is transported in blood plasma bound to haemoglobin
- Diffuses into erythrocytes and reacts with water to form H2CO3
What does CO2 affect ?
Blood pH
What is the bohr shift ?
Carbon dioxide produced during cellular respiration lowers blood pH and decreases the affinity of hemoglobin for oxygen
Where are the breathing control centers found ?
The medulla oblongata of the brain
What is the function of the medulla oblongata ?
Regulates the rate and depth of breathing in response to pH changes in the cerebospinal fluid
What is hypoxia ?
Low oxygen levels in the tissues
What is the V02max defined as ?
The rate of oxygen usage under maximal aerobic metabolism
What is oxygen uptake measured in ?
ml/min or ml/min/kg body weight
What does the V02 max rely on ?
Cardiovascular and respiratory performance
