Term
| 1st developmental step of lung structure |
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Definition
| a widely branched respiratory tree with a mucociliary cleaning mechanism |
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Term
| 2nd developmental step of lung structure |
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Definition
| a complex gas exchange region with a short diffusion distance |
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Term
| 3rd developmental step of lung structure |
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Definition
| a thick net of capillaries that stands in close contact with air spaces (blood air barrier) |
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Term
| 4th developmental step of lung structure |
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Definition
| a surface film (surfactant) that reduces surface tension and thereby reduces the tendency of alveoli to collapse |
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Term
| how is the lung subdivided morphogically? |
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Definition
1) air conducting part- air conducting respiratory passages
2) gas exchanging part- pulmonary parenchyma |
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Term
| prenatal function and lung state |
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Definition
serve function as amniotic fluid producing organ
air spaces filled with fluid that must be abruptly be replaced by air with the first breath |
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Term
| afterbirth lung function and lung state |
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Definition
| lungs srve fucntion as gas exchanger apparatus. dramatic change from fluid air at first breath |
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Term
| besides lung function what else changes dramatically after birth? |
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Definition
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Term
| name five stages of fetal lung developmental |
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Definition
embryonic
pseudoglandular
canalicular
terminal sac or saccular
alveolar |
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Term
| what happens during embryology stage? |
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Definition
- buds begin to form at the 26th day
-branching occurs from the 25th to the 32nd day
-cartilage and mesoderm appear
-connective tissue forms at the end of the 5th week
-abnormalities include Tracheo-esophageal fistula
-formation of BP segments marks the end of this stage
-During this stage, the lungs and the mesoderm are growing into bilateral pleural cavities |
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Term
| when does the embryonic period begin and end? |
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Definition
| starts at fertilization and ends at 5 weeks |
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Term
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Definition
-conducting system undergoes 16 or more generations of branching
-subsegments form (terminal bronchioles)
-ciliated cells form by 10th week
-pleura and lymphatics form by 8th week
-by week 14, 75% of airways are developed
-abnormalities include diaphragmatic hernia and agenesis |
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Term
| what weeks are included in the pseudoglandular period? |
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Definition
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Term
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Definition
-gas exchange portion of the lungs forms
-thinning of epithelium lining respiratory bronchioles
-capillary network begins to form
-by 20th week, type II pneumocytes appear
-abnormalities include pulmonary hypoplasia |
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Term
| what weeks are included in the canalicular period? |
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Definition
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Term
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Definition
-alveoli begin to develop
-type 1 and type II pneumocytes mature
-production of surfactant begins
-increase of lung volumes and surface areas
-at week 28 air/blood interface is sufficient to support extra uterine life |
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Term
| what weeks are included in the terminal sac or saccule period? |
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Definition
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Term
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Definition
-50 million by term
-300 million by 3 years of age
-alveoli increase in number and size until 8 years old. Then they only increase in size as the chest wall expands until 18 to 22 years of age
-surface area of the lungs by adulthood is the size of a tennis court |
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Term
| weeks included during the alveolar period? |
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Definition
| from 36 weeks to 8 years old |
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Term
| what blood vessel in the fetus has the most oxygenated blood? |
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Definition
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Term
| what is the shunt on the liver called? |
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Definition
| it is called the ductus venosus- the blood doesnt need to be detoxified. |
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Term
| what does the inferior vena cava carry? |
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Definition
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Term
| which compartment has the highest saturation of mixed blood? |
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Definition
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Term
| what are the two cardiac shunts in the fetus? |
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Definition
the ductus arteriosum
the foramen ovale |
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Term
| percent of blood that goes through the foramen ovale? |
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Definition
| 30% of blood from the inferior vena cava |
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Term
| what percentage of blood gos through the ductus arteriosus? |
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Definition
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Term
| how does pressure in compartment contribute to opening or closing of shunts? |
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Definition
- when the pressure of the right atrium is higher than the pressure of the left atrium, then the foramen ovale opens
-when the pressure in the left atrium is higher than the pressure in the right atrium, then the foramen ovale closes. |
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