What is expiratory reserve (ERV)
Extra air exhaled beyond normal expiration.
What is inspiratory reserve (IRV)
Extra air inhaled beyond normal inspiration. Measures maximal inspiratory effort.
CO2 - Capillary relationship
CO2 diffuses easily so perfusion and ventilation defects = hypercapnia or hypocapnia
What causes low V/Q?
Poor ventilation (COPD, asthma)
What causes high V/Q?
Poor perfusion (PE). This is a major cause of hypoxia
What is the pathophysiology of PNA?
Alveolar consolidation with neutrophils and fibrin. Impaired gas exchange, lobar or bronchopneumonia pattern
Emphysema Patho
Elastin breakdown from protease-antiprotease imbalnce leads to air trapping and decreased recoil.
Cellular changes in chronic bronchitis
Hyperplasia: Goblet cells increase mucus secretion
Hypertrophy: Thickened smooth muscle
Metaplasia: Coulmnar -> squamous = Decreased cilia and increased infection risk.
Explain oxyhemoglobin curve
Left shift = High affinity (alkalosis, hypothermia, hypocapnia)
Right shift = Decreased affinity (acidosis, hypercapnia)
Acyanotic heart defects
ASD, VSD, PDA -> Pulm overload.
Cyanotic heart defects
Tetralogy, transposition -> Desaturation.
Explain remodeling of the heart
RAAS activation and catecholamines induce hypertrophy, fibrosis, dilation which leads to systolic/diastolic dysfunction, which can lead to heart failure.
Explain the significance of chronic ischemia of the heart.
Myocardium downregulates metabolism and contractility to reduce O2 demand. Works at low but viable function, leads to remodeling.
Explain stunning
When reversible ischemic event is reversed/reperfused, there is Ca overload and an increase of free radicals.
Why is cancer “immortal”?
Telomerase is reactivated, telomere length is maintained, there is limitless replication and evasion of apoptosis as a result of p53 and BAX loss.
Describe angiogenesis in cancer
Angiogenesis in cancer is driven by VEGF and bFGF, activated by HIF-1a under hypoxia, and leaky vessels support tumor growth and metastasis.
What is the difference between oncogene and proto-oncogene?
A proto-oncogene encodes proteins in the process of signal transduction, celly cycle regulation, transcription, and DNA repair. Oncogenes disrupt normal cell growth and cause increased proliferation and decreased apoptosis.
