Week 4 -Pulmonary (Resperatory) Physiology Flashcards
What are the roles of the pulmonary system?
- Regulate plasma levels of oxygen and carbon dioxide - most important function - failure of this is fatal. duh.
- Regulate plasma pH
- Protect against inhaled pathogens
- Provide an adequate surface for gas exchange with the external environment
- Assure adequate alveolar air movement by alterations in rate and depth of ventilation
- Support vocalization of sound
What is the overview of pulmonary system?
- Oxygen and carbon dioxide move into and out of the blood at pulmonary and systemic capillaries
Pulmonary System Basic Anatomy
Describe the thoracic cavity when it is relaxed
- Diaphram is relaxed
- Lungs are inflated becuase of negative pressure in pleural space, lungs want to collapse and ribs want to expand which creates this negative pressure
Thoracic cavity during inhallation
- Diaphram contracts, moving downwards, lungs expand and pressure difference pulls air into lungs
What happens in thoracic cavity during exhalation?
- Diaphram relaxes and thoracic cavity volume decreases
- Valsalva manuver during defacation.. huge pressure of diaphram upwards.. this stops air going into lungs and venus blood flow to heart stops… FAINT.
- Next beat is bad too when blood flow returns to heart.. causes a huge beat with lots of pressure and can blow open vessels in brain causeing stroke - major cause of stroke in elderly..
What are the factors that affect airway resistance?
FLow = pressure diff / resistance
- Normally have very low resistance to air flow in lungs
- Upper airways - mucus or food obstruction
- Lower airways - just before alvioli - asthma, histamines cause this, parasympathetic neurons
- Bronchodialators - CO2 and epinepherine (think anaphylaxis)
What are normal circumstances of thoracic cavity (pleural space)?
What happens when this is disrupted?
- Normally, the pleural space is at subatmospheric pressure.
- Pneumothorax results in collapsed lung that cannot function normally
- Pneumothorax can also be caused by really bad infection… can also be caused by puncture
What is a spirometer?
- Used to asses resp function
What are the lung volumes and capacities?
Normal Values
Tidal Volume (VT)
Expiratory Reserve Voluem (ERV)
Residual Volume (RV)
Inpiratory Reserve Volume (IRV)
Vital Capacity
Dead Space
Dead space - air that is in nose and trachea..
What are the different types and patterns of ventilation?
Eupnea
Hyperpnea
Hyperventilation
Hypoventilation
Tachypnea
Dyspnea
Apnea
Hyperventilation - blows off CO2, vessels in brain constrict - ischemia - fainting- treatment is to breath into paper bag, this will increase CO2.
Classifications of Hypoxias..
Hypoxic
Anemic
Ischemic
Histotoxic
How is ventilation regulated?
Peripheral chemoreceptors
- Located in carotid and aortic arteries
- Specialized glomus cells
- Sense and respond to changes in PO2, pH, and PCO2
Central chemoreceptors
- Changes in CO2
Carotid Body Cell
- Carotid body oxygen sensor releases neurotransmitter when PO2 decreases
Central Chemoreceptors
- Central chemoreceptors monitor CO2 in cerebrospinal fluid
- Just need to know they sense this and react.. not how
Factors that effect respiration…
What is negative feed back system for changes in respiratory system?
- Plasma levels of oxygen, carbon dioxide and pH are the “Controlled Variables” that influence pulmonary (respiratory function.
- Response to increased plasma PCO2 and decreased PO2
Just recognize that there is a negative feedback process…
