Physiology Flashcards
4 steps of respiration?
Ventilation
Gas exchange (alveoli and blood)
Gas transport
Gas exchange (at tissue)
What is Boyle’s Law?
As the volume of a gas increases the pressure exerted by the gas decreases
Structure of cardiac muscle?
Striated with gap junctions for communication and desmosomes for adhesion
How does ventilation occur?
Chest wall stretches
The Increase in the size of the lungs make the intra-alveolar pressure to fall
The air then enters the lungs down its pressure gradient
What is alveolar surface tension?
Attraction between water molecules at liquid air interface- present in alveoli- stop COLLAPSE
What produces surfactant, and why?
Produced by type 2 alveoli
Lowers alveolar surface tension- prevents collapse
What is alveolar interdependence?
If an alveolus start to collapse the surrounding alveoli are
stretched and then recoil exerting expanding forces in the
collapsing alveolus to open it
Major muscle of inspiration?
Diaphragm and external intercostals
Accessory muscles of inspiration?
Sternocleidomastoid, scalenus, pectoral
What does parasympathetic innervation cause the bronchus to do?
Constrict
What does sympathetic innervation cause the bronchus to do?
Dilate
What is tidal volume?
Volume of air entering or leaving lungs during a single breath
What is residual volume?
Minimum volume of air remaining in the lungs even after a maximal expiration
What is functional residual capacity?
Volume of air in lungs at end of normal passive expiration
What is vital capacity?
Maximum volume of air that can be moved out during a single breath following a maximal inspiration
What is total lung capacity and how is it calculated?
Maximum volume of air that the lungs can hold
Vital Capacity + Residual Volume
Is actin thick or thin?
Thin
Is myocyin thick or thin?
Thick
How is muscle tension produced?
By sliding of actin filaments on myocin filaments
In cardiac muscle, where is the calcium released from?
Sarcoplasmic reticulum
What does inotropic mean?
Increase force of contraction
What does chronotropic mean?
Increase heart rate
Why is alveolar ventilation less than pulmonary ventilation?
Anatomical dead space
Causes of metabolic acidosis?
Lactic acidosis
Renal failure
Sepsis
Cause of metabolic alkalosis?
Vomiting
Causes of respiratory alkalosis?
Hyperventilation:
Anxiety
Pain
early sepsis
What is partial pressure?
The pressure that gas would exert if it occupied the total volume for the mixture in the absence of other components
Which part of the brainstem modifies respiration?
Pons
Which part of the brainstem generates the rhythm of respiration?
Medulla
What do central chemoreceptors respond to?
H+ level of CSF (increased H+ causes hypercapnia)
3 important pressures in ventilation?
Atmospheric
Intra-alveolar
Intrapleural