Lung anatomy

Question 1

all respiratory muscles are skeletal muscles

Answer 1

respiratory air flow is determined by the pressure difference between mouth and alveoli

Question 2

inspiration

Answer 2

-alveolar volume increases
-palv decreases
-inspriatory muscles contract
-Pip becomes more negative
-increases differente between Palv and Pip=increases Ptp
Important: Ptp is synonymous with alveolar wall distension-the larger the Ptp -the greater the alveolar wall distension

Question 3

Expiration

Answer 3

-alveolar volume decreases
-palv increases
-inspiratory muscles relax
-Pip becomes less negative
-decreases difference between Palv and Pip=decreases Ptp
so, if Ptp is smaller -the alveolar wall recoils-elastic recoil

Question 4

Pneumothorax

Answer 4

-pleural seal broken ,with pathway either:
inwards through lung tissue
outwards through chest wall
-negative pressure can’t be generated-.ventilation ineffective
-natural tendency of lung to collapse now unopposed
-elastic ercoli of alveoli

Question 5

Resistance

Answer 5

• resistance of respiratory tract to airflow during inspiration and expiration
• affected by diameter of airways

Question 6

compliance

Answer 6

-expandibilty of lungs, low compliance -fibrosis
high compliance-emphysema
value varies as lungs inflate

Question 7

Poiseuille’s law

Answer 7

directly proportional to viscosity of fund and the length of tube and inversely proportional to the forth power of the radius of the tube
conditions associated with changes in r
-asthma,bronchitis,croup

Question 8

smooth muscle

Answer 8

• contains thick myosin and thin actin ,no troponin
• actin and myosin not organised into myofibrils, no sarcomeres
• contraction initiated via Ca2+ as with skeletal muscle

Question 9

bronchial smooth muscle contractions

Answer 9

• a number of triggers can cause initiation of contraction in the bronchi
• calmodulin +Ca2+ complex activates MLCK
• to relax myosin must be dephosphorylated and Ca2+ extruded out of the cell or to the SR

Question 10

mid clavicular line

Answer 10

6th rib

Question 11

mid axillary line

Answer 11

8th rib

Question 12

mid scapular line

Answer 12

10th rib

Question 13

right lung

Answer 13

3 lobes

Question 14

left lung

Answer 14

2 lobes

Question 15

cystic fibrosis

Answer 15

• chloride ions blocked
• sodium does not follow chloride ions
• water does not follow sodium ion
• dehydration of mucus sets in