11-1: 11/28: Pulmonary Anatomy And Control Of Breathing

Front 1

What is the principal muscle of breathing?

Back 1

Diaprhagm--but not absolutely necessary for breathing to occur

Front 2

Which nerves innervate the diaphragm and from which roots do they originate?

Back 2

Phrenic nerve from C3, C4, C5

Front 3

Motions of the diaphragm:
Piston-like vs Non-piston Like

Back 3

Piston-like: Contraction shortens muscle, expands throacic volume by displacing ABDOMINAL contents ANTERIORLY

Non-piston: Lower thorax (ribs) moved outward

So chest doesn't just move anteriorly, also moves outward

Front 4

What are the accessory muscles of inspiration?

Back 4

External intercostals
Scalenes (attach to upper ribs)
SCM

Front 5

What are the accessory muscles of expiration?

Back 5

Internal intercostals
Abdominal muscles

Front 6

What pressure changes occur during breathing?

In quiet breathing, is expiration or inspiration active?

Back 6

Inspiration: active; negative pressure, air flows into lungs

Expiration: passive; pressure is positive, air flows out

***Changes in intrathoracic pressure result from changes in volume***

Front 7

Bucket-handle vs Pump-handle movements of inspiration.

Back 7

Bucket-handle: lower ribs--movement in transvarse (outward) directions during inspiration

Pump-handle: upper ribs--motion of ribs expand chest in A-P diameter

Front 8

What structures comprise the upper airway? Role in breathing?

Back 8

Nose, mouth, pharynx, larynx

Filter, warm, humidify inspired air

Front 9

Role of genioglossus in breathing.

Back 9

Genioglossus = pharyngeal dilator muscle; contracts to maintain patency of airway

Front 10

Role of larynx in breathing.

Back 10

Connects pharynx to trahea; allows phonation

Front 11

Trachea:
Cell histology
Position of catilage

Back 11

Trachea:
lined by ciliated pseudostratified columnar epithelium
C-shaped cartilage anterolaterally ONLY; no cartilage posteriorly

--bifurcates into mainstem bronchi

Front 12

What structures comprise the conducting airways?

Back 12

Trachea, bronchi, bronchiles, terminal bronchioles, transitional bronchioles

Front 13

What structures comprise the acina airways?

Back 13

Transitional bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs

In summary, about 23 generations of branching!

Front 14

Bronchi:
Cell histology (mucosa vs submucosa)
Position of cartilage

Back 14

Bronchi:
Mucosa lined by ciliated pseudostratified columnar epithelium
Submucosa contain mucus glands, SM, lymphoid tissue

Carilage is distributed in walls cirfumferentially

Front 15

Bronchioles vs Bronchi

Back 15

Bronchioles: no longer have cartilage in walls; lined by ciliated simple cuboidal epithelium

Bronchi: circumferential distribn of cartilage, lined by ciliated pseudostrat columnar epithelium

Front 16

What are the contents o a secondary pulmonar lobule?

Back 16

well-defined by interlobular septa and contain 3-5 terminal bronchioles, and many resp bronchioles, alveolar ducts, and alveoli

Front 17

Primary Pulmonary Lobule:
Role
Contents

Back 17

Functional gas exchange unit of lung

Consists of respiratory bronchiole, alveolar ducts, and alveoli arising from this bronchiole

Front 18

What is senile emphysema?

Back 18

Enlargement of alveolar ductal airspaces seen in lungs of the elderly; a NORMAL process

Front 19

Role of Clara Cells

Back 19

More common distal airways; have secretory functions, and probably can replicate (~stem cells)

Front 20

Up until what point is the respiratory epithelium cliated?

Back 20

Ciliated through bronchiolar level

Front 21

How does pulmonary circulation differ from systemic circulation in terms of pressure, vascular resistance, and cardiac output?

Back 21

Pulmonary circulatino is a low pressure system, with low vascular resistance; howver, handles same cardiac output that systemic circulation does.

Note: Lungs have dual circulation: pulmonary and bronchial.

Front 22

How is the low vascular resistance of pumlonary circulation achieved?

Back 22

Low resistance achieved by vasodilated state (which is induced by vasoactive mediators secreted by endoehtlial and SM cells)

Front 23

Which arteries in the lung arise from systemic circulation (aorta)?

Back 23

Bronchial arteries

Front 24

How does bronchial circulation differ from pulmonary circulation?

What is its role?

Back 24

Bronchial arteries (which oiginate from systemic circulation) are HIGH pressure; supply nutrients, heat to airways

(Some bronchial venous blood mingles with pulm venous blood and forms physiologic shunt)

Front 25

The pulmonary lymphatics drains fluid from the ____________ and returns it to vascular system via ________.

Back 25

Pulm lymphatics drain filtered fluid from LUNG INSTERSTITIUM and return it to vasc system via THORACIC DUCT

Front 26

What is the pleura?

Static and dynamic functions?

Back 26

Pleura: airtight space lined by mesothelial cells

Static fn: couples lungs to chest wall

Dynamic fn: fluid in pleural space acts as lubricant (allows lungs to move freely)

Front 27

Where is the respiratory center in the brain located? How can it be bypassed?

Back 27

Medullary esp Center (sends signals via spinal cord to phrenic nerve)

Can be bypassed by voluntary centers in motor cortex temporarily

Front 28

Pre-Botzinger Complex:
Role in breathing

Back 28

Generated rhythm of breathing; located in medulla!

Front 29

Opioid receptors in the ________ can _______ breathing.

Back 29

Opioid receptors in pre-Botzinger complex can SUPPRESS breathing

Front 30

Maintenance of constant ___________ is the major influence on respiratory drive.

Back 30

Constant arterial CO2 = major influence on respiratory drive

Note: elevated CO2 stimulates ventilation but depressed CO2 can result in apnea (cessation of breathing)

Front 31

How does the influence of O2 on respiration differ from the influence of CO2?

Back 31

Changes in CO2 result in steep respiratory changes

Changes in O2 don't result in respiratory changes (stimulation of ventilation) until levels fall significantly before normal

Front 32

Central chemoreceptors vs Peripheral chemoreceptors:
Location
Response (triggers and time of response)

Back 32

Central chemoreceptors found throughout brainstem and cerebellum; respond to CSF pH changes (which changes in response to CO2 changes; high CO2-->decreased pH-->increased breathing)

Peripheral chemo: respond to CO2 and O2; causes increased ventilation; located in carotid sinus; less sensitive to CO2 than central chemoreceptors, and act FASTER than chemoreceptors

Front 33

What nerve is required for respiratory tract receptor reflexes?

NT required?

Back 33

Vagus efferents which release ACh and induces bronchial SM bronchoconstriction with increased mucosal secretions