Lungs- General Anatomy, Structure & Function

Question 1

what occurs to the trachea

Answer 1

turn into right and left principle bronchus (primary/chief) –> enter at “root” or hilus of lung

Question 2

what is the tracheal bronchus

Answer 2

in ruminant and pigs –> cranial to bifurcation –> cranial lobe right lung

Question 3

what occurs to bronchus

Answer 3

subdivided –> lobar; segmental; med-small bronchi

Question 4

what occurs to cartilage support with increasing subdivision of bronchus

Answer 4

cartilage support decreases with subdivision

Question 5

what is the final part of the airway conducting system

Answer 5

bronchioles and terminal bronchioles

Question 6

do bronchioles have cartilage support

Answer 6

no

Question 7

what are the structures shown in the bronchgram

Answer 7

Question 8

what is the pathway of air from the trachea to lungs

Answer 8

trachea –> left and right primary bronchus (+ tracheal bronchus)

Question 9

where does deoxygenated blood travel from

Answer 9

from heart to lungs –> pulmonary trunk –> left and right pulmonary arteries

Question 10

where does oxygenated blood travel

Answer 10

from lungs returns to heart via pulmonary veins

Question 11

where do bronchial arteries arise and what is their function

Answer 11

directly from aorta and supply lung tissue with oxygenated blood

Question 12

what occurs to cartilage in the intra-pulmonary branches

Answer 12

cartilage rings become irregulat plates

Question 13

what forms between the cartilage and mucosa of intra-pulmonary branches

Answer 13

smooth muscle forms continuous spirals between cartilage and mucosa

Question 14

what is the function of smooth muscle in the intra-pulmonary branches

Answer 14

controls airway diameter –> parasympathetic constriction

asthma: sympathomimetric drugs cause relaxation

smooth muscle continues to level of alveolar ducts

Question 15

what glands are present in intra-pulmonary branches

Answer 15

seromucus glands

Question 16

what is BALT

Answer 16

bronchial associated lymphoid tissue in lamina propria

Question 17

what cells become less numerous in the intra-pulmonary branches

Answer 17

goblet cells

Question 18

what are these structures

Answer 18

Question 19

what is the difference between a bronchus and bronchiole

Answer 19

bronchus has cartilage support, ciliated epithelium

bronchiole more simplified epithelium, no BALT

Question 20

what are the features of bronchioles (5)

Answer 20

1. no cartilage
2. no seromucus glands
3. smooth muscle persists
4. simple cuboidal epithelium
5. club cells (clara cells) dominate
6. goblet cells gradually disappear

Question 21

what structure is this

Answer 21

bronchiole

Question 22

how do bronchioles prevent themselves from collapsing

Answer 22

have elastic fibres within walls –> elastic recoil after contraction of smooth muscle

produces surfactant –> changes surface tension

Question 23

what cells are these and where are they

Answer 23

club cells

in bronchioles

Question 24

what are the structures

Answer 24

Question 25

what are the 2 main cell types in the alveoli

Answer 25

1. type 1 pneumocyte (97%) 2. type 2 pneumocyte (3%)

Question 26

what are type 1 pneumocytes

Answer 26

squamous alveolar

Question 27

what are type 2 pneumocytes and what is their function

Answer 27

septal cells produce surfactant reduces surface tension and stops alveolar collapse

Question 28

what are the alveolar structures

Answer 28

Question 29

what is another cell type in alveoli

Answer 29

alveolar macrophages

Question 30

what are the functions of alveolar macrophages

Answer 30

defence of lung efficient phagocytes carried along with surfactant to pharynx and swallowed

Question 31

where do alveolar macrophages reside

Answer 31

cross alveoli capillary wall to reside on gaseous surface of alveolus (diapedesis)

Question 32

what is the origin of alveolar macrophages

Answer 32

bone marrow monocyte

Question 33

what is the blood gas barrier and its 3 components

Answer 33

1. type 1 pneumocyte (alveolus) 2. fused basal membranes of alveolar and endothelial cells 3. endothelial cell (capillary)

Question 34

how does the larynx, trachea and lung develop embryonically

Answer 34

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

Question 35

what is the cartilage/smooth muscle components derivered from

Answer 35

mesoderm

Question 36

what are the phases of lung parenchyma development

Answer 36

1. pseudo glandular phase: mid gestation-bronchial pattern becomes established 2. canalicular phase: alveoli begin to develop 3. saccular phase: type 2 pneumocytes form and start to produce surfactant 4. alveolar phase: alveoli continue to develop after birth lung is fluid filled and alveoli are collapsed until first breath

Question 37

what are the structures

Answer 37

Question 38

what structure is this

Answer 38

alveoli