Pulm #1: Anatomy And Control Of Breathing

Front 1

1. What is the principal muscle of breathing?

2. What is it's innervation?

3. Actions/direction of movement?

Back 1

1. Diaphragm

2. C3, C4, C5 (roots that supply phrenic nerve)

3. ↑volume (↓P in chest --> intake air).
piston like= expands downwards.
non-piston like= expands outwards (push out ribs).

Front 2

Functions of the bony thorax?

Back 2

1.Attachment (for muscle of resp.)
2. Protect internal organ
3. Ventilation (can expand and increase volume)

Front 3

Accessory muscles of respiration for-

1. Inspiration
2. Expiration

Back 3

1. Inspiration (external intercostals, scalenes, SCM)
2. Expiration (Internal intercostals, abdominal)

Front 4

Active or passive: inspiration vs. expiration

How many dimensions does the chest expand in and what directions does it have?

Back 4

Inspiration = active, Expiration= passive

3 dimensions, A-P (pump handle), Transverse (bucket handle)

Front 5

Function of the upper airway?

The ____ maintains patency of the airway.

The ____ protects the airway from swallowing foreign objects.

The larynx connects the ____ to the ____. Function?

Back 5

Function: filters, warms, and humidifies air.

Genioglossus (pharyngeal dilator)

Epiglottis, glottis protect airway

Larynx connects pharynx to trachea

Front 6

What type of epithelium lines the trachea?

Why is it plausible that esophageal tumors can constrict the trachea?

Back 6

Ciliated pseudostratified columnar epithelium

C shapes cartilage rings anteriorly. So posterior eosphageal tumors can compress trachea (b/c of lack of cartilage).

Front 7

What is the Carina?

Difference between the Conducting and Acinar airways?

Back 7

Carina= midpoint (when trachea branches into mainstem bronchi)

Conducting- no gas exchange, just passage of air

Acina- respiratory bronchioles and alveolar ducts and sacs (site of gas exchange)

Front 8

What must air travel through when inhaled through nose?

(include how many generations of airways you would have to go through?

Back 8

Nose- nasopharynx- larynx-trachea-bronchi-bronchioles-terminal bronchioles-23 division of airway-alveolus

Front 9

Layers of the wall of the bronchus from out to in.

What happens to branching frequency and cross sectional area as you move distally?

Back 9

Ciliated pseudostratified columnar - smooth muscle- glands- cartilage (plates)

Branching becomes more frequent and cross sectional area increases in small airways.

Front 10

What do the terminal bronchioles give rise to? How many branches before you get pure alveolar sacs?

Back 10

Terminal bronchioles --> respiratory bronchioles (have alveoli protruding off walls)

8-9 generations of branching between TB and alveolar sacs

Front 11

What is the basic gas exchange unit of the lung?

Primary vs. Secondary pulmonary lobule

Back 11

Basic unit = acinus

Primary= acinus (RB, alveolar duct, alveoli)
Secondary= polyhedral structure bound by fibrous septa, contain up to 12 acini/lobule

Front 12

What are the "Pores of Kohn"?

Layers that air passes through from lumen when air is inhaled?

Back 12

Lumen --> alveolar epithelium --> fused basement membrane --> capillary endothelium --> blood

Front 13

What is "respiratory epithelium"? How does it change throughout the airway?

Back 13

Ciliated, pseudostratified columnar epithelium. @ level of Bronchiole --> simple epithelium
@ level of Alveolus --> no longer ciliated

Front 14

Name some different cell types in the respiratory epithelium.

What is the "mucociliary ladder"?

Back 14

Epithelial cells, Goblet cells (mucous), Basal cells (stem cell-like fxn), Mast cell (immune), Clara cell (secretory role, surfactant like substance), Neuroendocrine cell

Mucociliary ladder- cilia beat upwards, moving mucous with trapped pathogens out through the trachea.

Front 15

SIADH is commonly associated with what type of carcinoma?

Back 15

Small cell lung cancer (APUD, i.e. neuroendocrine cells can mutate and give rise to this cancer)

Front 16

Type 1 vs. Type 2 alveolar cell

Back 16

Type 1: gas exchange, thin walls, large surface area (cover 91% of alveolus) but least numerous

Type 2: surfactant production, smaller surface area but more numerous

Front 17

What are "Dust cells"?

When does a type 2 cell mature?

Back 17

Dust cell= alveolar macrophages (remove debris)

Type 2 cells mature in late gestation (after 24 weeks, cells start making surfactant but doesn't get going till 36 wks).

*NRDS (neonatal RDS)- premature babies, lack of surfactant

Front 18

What are the "dual circulation of the lungs"?

Back 18

Pulmonary Circulation and Systemic circulation.

Pulmonary- RV to PA to lungs
Bronchial- Systemic circulation (aorta) to bronchial artery to airways

Front 19

Describe the pressure, vascular resistance, and distensibility of pulmonary circulation as compared to the systemic circulation.

Back 19

LOW pressure (RV can't generate as much force because weak muscle)

LOW resistance (vasodilated, allows low resistance to flow)

HIGHLY distensible

Front 20

What is the function of bronchial circulation?

What is the meaning of the "physiologic shunt"?

Back 20

Bronchial circulation= supplies nutrients, heat to airways

Deoxygenated bronchial venous blood mixes with pulmonary venous blood (so pulm venous return is not 100% oxygenated)

Front 21

Where does leaked fluid that ends up in the interstitum of the lung go?

Back 21

Pulmonary lymphatic returns fluid to vasculature via THORACIC DUCT (drains into left Brachiocephalic vein).

Front 22

Origin of the pleura?

What are the two functions?

Back 22

Origin= mesothelial cells (from celomic cavity during fetal growth)

Static- couples lung to chest wall (separates lobes of the lung)

Dynamic- fluid acts as lubricant

Front 23

What three factors govern breathing pattern? Which is the most important?

Back 23

- CO2 excretion (maintenance of CO2 levels = most important factor)
- Demand for O2
- Acid-base balance (pH)

Front 24

Where does the signal for normal breathing originate and where does it end up?

What happens when you hold your breath?

Back 24

Respiratory neurons in medulla --> bulbospinal tract --> C3,C4,C5 --> phrenic --> diaphragm

When you hold your breath--> voluntary center in motor cortex sends signal down corticospinal tract (CST) --> bypasses medulla and inhibits breathing (temporarily)

Front 25

What is the "core rhythm generator"?

Back 25

- Group of inspiratory neurons in medulla (send output to phrenic)
- Influenced by signals in medulla, pons, and chemoreceptors.
- contains opioid receptors that inhibit receptor activity

Front 26

Ventilation _____ (↑↓) profoundly with small rises in arterial PCO2.

What is the response to CO2 in the setting of hypoxia? decreased sleep? narcotics?

Back 26

Ventilation INCREASES with small rises in pCO2 (want to blow it off to maintain pH).

With hypoxia, CO2 response increases.
With lack of sleep and narcotics response decreases (APNEA of SLEEP).

Front 27

How does PO2 stimulation of ventilation differ from PCO2 stimulation of ventilation?

Back 27

pO2, unlike pCO2, levels must fall SIGNIFICANTLY below normal in order for ventilation to be stimulated.

Front 28

Central vs. Peripheral chemoreceptors

What stimulates each?

Back 28

Central= multiple sites in medulla and cerebellum (sense pH in CSF)

Peripheral= carotid body & aortic body (sense ↓ arterial pO2, ↓ pH, ↑ pCO2)

Front 29

What are some different respiratory tract receptors?

What is an example of a common reflex that they mediate?

Back 29

stretch, mechanoreceptors, cold receptors, C-fibers, irritant

-->mediate COUGH for example

Front 30

What are the following reflexes:

- Hering-Breuer reflex
- Diving reflex
- Cough reflex

Back 30

- Hering-Breuer: inhibit inspiration with sustained inflation of lung

- Diving reflex: cold water on face stimulates apnea and bradycardia

- Cough: initiated by activation of irritant or mechanoreceptors in larynx, airways.

Front 31

Difference between sympathetic and parasympathetic input to the lungs.

Back 31

Sympathetic (Epi/catecholamines released --> binds to B2 adrenergic receptor on smooth muscle --> bronchodilation)

Parasympathetic (vagus efferents release Ach --> cause bronchoconstriction of smooth muscle AND increase secretion of mucous gland)