Lungs- General Anatomy, Structure & Function Flashcards
what occurs to the trachea
turn into right and left principle bronchus (primary/chief) –> enter at “root” or hilus of lung
what is the tracheal bronchus
in ruminant and pigs –> cranial to bifurcation –> cranial lobe right lung
what occurs to bronchus
subdivided –> lobar; segmental; med-small bronchi
what occurs to cartilage support with increasing subdivision of bronchus
cartilage support decreases with subdivision
what is the final part of the airway conducting system
bronchioles and terminal bronchioles
do bronchioles have cartilage support
no
what are the structures shown in the bronchgram
what is the pathway of air from the trachea to lungs
trachea –> left and right primary bronchus (+ tracheal bronchus)
where does deoxygenated blood travel from
from heart to lungs –> pulmonary trunk –> left and right pulmonary arteries
where does oxygenated blood travel
from lungs returns to heart via pulmonary veins
where do bronchial arteries arise and what is their function
directly from aorta and supply lung tissue with oxygenated blood
what occurs to cartilage in the intra-pulmonary branches
cartilage rings become irregulat plates
what forms between the cartilage and mucosa of intra-pulmonary branches
smooth muscle forms continuous spirals between cartilage and mucosa
what is the function of smooth muscle in the intra-pulmonary branches
controls airway diameter –> parasympathetic constriction
asthma: sympathomimetric drugs cause relaxation
smooth muscle continues to level of alveolar ducts
what glands are present in intra-pulmonary branches
seromucus glands
what is BALT
bronchial associated lymphoid tissue in lamina propria
what cells become less numerous in the intra-pulmonary branches
goblet cells
what are these structures
what is the difference between a bronchus and bronchiole
bronchus has cartilage support, ciliated epithelium
bronchiole more simplified epithelium, no BALT
what are the features of bronchioles (5)
- no cartilage
- no seromucus glands
- smooth muscle persists
- simple cuboidal epithelium
- club cells (clara cells) dominate
- goblet cells gradually disappear
what structure is this
bronchiole
how do bronchioles prevent themselves from collapsing
have elastic fibres within walls –> elastic recoil after contraction of smooth muscle
produces surfactant –> changes surface tension
what cells are these and where are they
club cells
in bronchioles
what are the structures
what are the 2 main cell types in the alveoli
- type 1 pneumocyte (97%)
- type 2 pneumocyte (3%)
what are type 1 pneumocytes
squamous alveolar
what are type 2 pneumocytes and what is their function
septal cells
produce surfactant
reduces surface tension and stops alveolar collapse
what are the alveolar structures
what is another cell type in alveoli
alveolar macrophages
what are the functions of alveolar macrophages
defence of lung
efficient phagocytes
carried along with surfactant to pharynx and swallowed
where do alveolar macrophages reside
cross alveoli capillary wall to reside on gaseous surface of alveolus (diapedesis)
what is the origin of alveolar macrophages
bone marrow monocyte
what is the blood gas barrier and its 3 components
- type 1 pneumocyte (alveolus)
- fused basal membranes of alveolar and endothelial cells
- endothelial cell (capillary)
how does the larynx, trachea and lung develop embryonically
ventral outgrowth of primitive pharynx (foregut, endoderm)
tracheo-esophageal septum eventually separates trachea and esphagus at level of developing larynx
blind ending respiratory diverticulum continues to grow caudally into mesoderm –> splits into 2 lung buds, buds further split to form the bronchial tree
what is the cartilage/smooth muscle components derivered from
mesoderm
what are the phases of lung parenchyma development
- pseudo glandular phase: mid gestation-bronchial pattern becomes established
- canalicular phase: alveoli begin to develop
- saccular phase: type 2 pneumocytes form and start to produce surfactant
- alveolar phase: alveoli continue to develop after birth
lung is fluid filled and alveoli are collapsed until first breath
what are the structures
what structure is this
alveoli
