physiology this week hemorrhage diagram due on friday: 15 minutes to complete from memory. check the...
TRANSCRIPT
Physiology This Week
Hemorrhage Diagram due on Friday: 15 minutes to complete from memory.Check the website for Schedule of times Assistants are available.
Lab this week: Respiratory Physiology. A case study and lung function tests.Bring your textbook and a calculator.
Announcement about Exam Schedule.
Bronchopulmonary segments and Surgical resection
Bronchopulmonary segments and Surgical resection
Why is lung cancer so common?Why is lung cancer so common?
How are the delicate living tissues of the respiratory protected?
How are the delicate living tissues of the respiratory protected?
RespiratoryEpitheliumof Airway(Not alveolus!)
Goblet cells, ciliated cells and
the mucus escalator
Smoker’s hackSmoker’s hack
Cystic fibrosisCystic fibrosis
Figure 13-2
Anat
omic
al D
ead
Spac
e
Impaction
Sedimentation
Brownian Diffusion
Particle Filtration: deposition varies
DecreaseIn Velocity
Pulmonary arterial blood = low in O2Pulmonary arterial blood = low in O2
Cartilage prevents collapse of airways during expiration.
V/Q inequality = imperfect match between air flow and blood flow
Response of pulmonary arterioles to low P O2
Matching blood flow (Q, also called “perfusion” ) to ventilation (V) by pulmonary arterioles that constrict in response to low O2 anddilate in response to hi O2
(Note this response to O2 is opposite that of systemic arterioles!)
Thus, poorly ventilated regions of the lung will receive less blood flow.
So…. Q is “matched” to V, but not perfectly.
And low perfusion in a region leads to bronchoconstriction.
V/Q inequality
V/Q inequality is the result of an imperfect match between blood flow and air flow
At rest, capillaries at the upper extend of the lungs mayhave no blood flow, due to low pressure in the pulmonary circuit.
Type I pneumocytes are simple squamous epithelia that comprise the majority of the surface area.
Type II pneumocytes secrete surfactant.
Gas exchange by diffusion based on gradients.
Elastin fibers in interstitium stretch with inhalation, recoil assists exhalation.
Chronic inhalation of irritants stimulates alveolar macrophages………Degradation of elastin &Isolation by fibroblasts (fibrosis)
Surfactant reduces surface tension which reduces the mechanical effort of ventilation and prevents the collapse of smaller alveoli.
Who cares? Respiratory Distress Syndrome of the Newborn
Elastin fibers in interstitium stretch with inhalation, recoil assists exhalation.
Chronic inhalation of irritants stimulates alveolar macrophages………Degradation of elastin &Isolation by fibroblasts (fibrosis)
Compliance and elastance of balloon and plastic bag.
Syringe with internal spring
V = VT x f
VA = (VT – VDS) x fAnatomic dead space = air remaining in conducting zone (typically 150 ml.)
What is VA if Tidal Volume is 150 ml?
O2 uptake
CO2 production= Respiratory Quotient
=0.8 for mixed diet 200mlCO2/min250 ml O2/min
= 0.8 for proteins= 0.7 for fat= 1.0 for carbohydrate
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy
Figure 13.27
CO2 and O2 bound to Hb do not contribute to partial pressure (no longer a dissolved gas!)
Bound & Free
Peripherial chemoreceptors can detect ONLY dissolved gasses!
Partial Pressures are the same, but total oxygen content differs!