1. The Lungs and Chest Wall
Chapter 2

2. The Lungs as Organs Apex: upper rounded part of lung
apices extend above clavicles
Base: lower concave part of lung
Rests on the diaphragm
Major muscle of ventilation
Separates the thoracic and abdominal cavity
Mediastinum contains heart, aorta, esophagus, great veins, trachea, mainstem bronchi

3. Lung Topography

4. Lung Features Diaphragm ≈ 9th-11th rib COPD = Lower Rt Lung = 3 lobes
Lt Lung = 2 lobes
Which one has less volume?
Left side… Because of the heart

5. Lungs as Organs (cont’d)
Cardiac notch—left lung’s anterior border
Diaphragm—major muscle of ventilation
Separates thorax from abdomen
Dome-shaped
Lower margin at T10
Highest margin T8-T9
Right hemi-diaphragm is higher than left
Liver pushes it up; heart pushes left side down

6. Hilum Pulmonary ligament
where arteries, veins, and bronchi enter and leave lungs
Pulmonary ligament
connects lung’s surface membrane with diaphragm
Lingula: tongue-like anterior portion of left upper lobe that overlaps heart
Lingula = counterpart of right middle lobe
Hilum
where arteries, veins, and bronchi enter and leave lungs
Pulmonary ligament
connects lung’s surface membrane with diaphragm
Lingula: tongue-like anterior portion of left upper lobe that overlaps heart
Lingula = counterpart of right middle lobe

7. Pleural Membranes Form sealed envelope around each lung
Visceral pleura
attached to lung’s surface
Parietal pleura
attached to inner chest wall surface
Pleural space
potential space between visceral and parietal pleura
Visceral pleura
attached to lung’s surface
Parietal pleura
attached to inner chest wall surface
Pleural space
potential space between visceral and parietal pleura

8. Pleural Membranes Visceral pleura Parietal pleura Pleural space
attached to lung’s
surface
Parietal pleura
inner chest wall surface
Pleural space
potential space between visceral and parietal pleura
Form sealed envelope around each lung
Visceral pleura
attached to lung’s surface
Parietal pleura
attached to inner chest wall surface
Pleural space
potential space between visceral and parietal pleura

9. Costophrenic Angles Where lowest margin of diaphragm meets chest wall
Pleural effusion
fluid in pleural space
fluid settles into costophrenic angles, blunting their points on chest x-ray images
thoracentesis — surgical removal of excess pleural fluid via tube insertion into pleural cavity

11. Blood Supply to the Lungs
Mr. Cosa’s Drawing

12. Rough Schematic

13. Pulmonary Blood Flow

14. Regulation of fluid in the lung: Lymphatic System
Lymph: clear, protein-containing fluid in interstitial spaces (Pleura)
Normal fluid filtration
30 L plasma/day filters into interstitium
27 L plasma/day gets reabsorbed
3 L in lung interstitium returns to the systemic circulation via the lymphatic system
If Lymphatic System does not filter the 3 L out, it can accumulate in the alveoli and cause pulmonary edema

15. Somatic nervous system
The Nervous System
Central nervous system (CNS)
Brain & Spinal cord
Peripheral nervous system
(portion of nervous system laying outside brain and spinal cord)
Sensory (afferent) neurons – Carry signals that are transmitted to the brain and spinal cord
Motor (efferent) neurons – carry signals away from CNS
Autonomic nervous system
Non voluntary
Parasympathetic branch
Sympathetic branch
Affarent – Signals that are transmitted to the brain and spinal cord
Somatic Neurons send motor signals… Motor signals are those signals that tell the body to lift, walk, or breath… In order for you to manipulate and stop these neurons, you have to induce paralysis… Those drugs are called “neuromuscular” blocking agents…
Autonomic Nervous System controls the involuntary movements of the body… For example – Heart Rate… Pupil Dilation… Salivation…
And from here you can break it up into two categories… The parasympathetic and sympathetic branches.
Somatic nervous system

16. Autonomic Afferent Neurons Somatic Neurons
So again, you have the affarent neurons…
They send signals regarding what you see, feel, hear… They send signals back to the brain and spinal cord
The Somatic motor neurons are voluntary control of the skeletal muscle… Your brain sends signals whenever you want to lift, walk, or run…
And then the Autonomic are the signals that are sent that you have no control over… They are called “involuntary” control… heart beat.. Eye dilation… adrenaline pumping… etc..
Table 2-1 (pg. 29) shows you the function of the Somatic And Autonomic System.
Ach = Acetylcholine
NE = Norepinephrine
Both of these are what we call “neurotransmitters”… These are chemicals your body produces and shoots from the end of the nerves… It’s like “wifi” transmission… but chemicals… with no nerve attached…

17. Phrenic nerves Intercostal nerves Stimulation of Diaphragm
If injury from surgery, disease, or trauma
may paralyze diaphragm
breathing is possible if accessory nerves are intact
Intercostal nerves
spinal nerves that stimulate/innervate intercostal muscles
Phrenic Nerves Originate from C3 – C5 of the cervical (head) nerves

18. Autonomic Innervation
Controls Involuntary Movements
Example: Heart Rate… Pupil Dilation… Salivation…
Two branches arise:
Sympathetic
Parasympathetic
Autonomic Nervous System controls the involuntary movements of the body…
For example – Heart Rate… Pupil Dilation… Salivation…

19. Sympathetic (Adrenergic)
Innervates
adrenal medulla
Neurotransmitter = Noradrenaline
Aka norepinephrine
Alpha, Beta 1, Beta 2
Stimulation of ß2 receptors in the airway causes bronchodilation
Draw both sides of the system

20. Which would you recommend?
Alpha vs. Beta 2
Upper airway swelling s/p extubation
Lower airway wheezing/asthma
clinical Focus 2-4 pg. 36
This question is in clinical Focus 2-4 pg. 36

21. Parasympathetic (Cholinergic)
Innervates
smooth airway muscle
mucous glands
pulmonary vasculature
Neurotransmitter = Acetylcholine
Overstimulation
bronchospasm
increased mucous production & thickness
Innervates = excites

22. Thoracic Anatomy Thorax is formed by rib cage and intercostal muscles
vertebrae
sternum
diaphragm

23. Thoracic Cage 12 ribs 7 attach directly to sternum anteriorly
3 (ribs 8-10) connect to sternum
2 do not attach anteriorly
floating ribs
Puncture – Pneumothorax
Fracture – Flail Chest

24. Ventilatory Muscles Primary muscles used for quiet breathing
Diaphragm (major effect)
Scalenes (minor effect)
Accessory muscles used for increased work of breathing (WOB)
scalenes (inspiration)
sternomastoids (inspiration)
pectoralis major (inspiration)
abdominals (expiration)
Diaphragm (major effect)
parasternal intercostals (minor effect)
Scalenes (minor effect)
scalenes (inspiration)
sternomastoids (inspiration)
pectoralis major (inspiration)
abdominals (expiration)

25. Muscles of Ventilation
Diaphragm (major effect)
Scalenes (minor effect)
scalenes (inspiration)
sternomastoids (inspiration)
pectoralis major (inspiration)
abdominals (expiration)
Fig. 2-13