Lecture 16: Mediastinum, Lungs, Pleura

Question 1

what structures are found w/in the mediastinum

Answer 1

heart, great vessels, esophagus, trachea, autonomic and phrenic nerves, thymus, thoracic duct

Question 2

what organs do the great vessels supply blood to?

Answer 2

head, neck, thoracic limbs

Question 3

what spinal cord levels is the phrenic nerve located

Answer 3

C5-C7

Question 4

sheets of mesothelium (single cell layer) that secrete small amounts of fluid and compost the pleura

Answer 4

serous membrane layer

Question 5

what is the function of pleura

Answer 5

allows the external surfaces of lung lobes to smoothly glide during expansion and deflation

Question 6

the out pouching of the foregut forms the ??

Answer 6

respiratory diverticulum AKA tracheobronchial diverticulum

Question 7

what does the tracheobronchial tube form

Answer 7

larynx, trachea, lungs

Question 8

what is the visceral pleura adherent to? what is the parietal (costal) pleura adherent to?

Answer 8

Visceral pleura - lung surface
Parietal (costal) pleura - body wall

Question 9

what is central circulation and its inlet/outlet

Answer 9

blood supply to the heart
inlet: coronary arteries
outlet: cornonary sinus

Question 10

what is systemic circulation and its inlet/outlet

Answer 10

oxygenated blood flow to the body

inlet: aorta
outlet: vena cavae

Question 11

what is pulmonary circulation and its inlet/outlet

Answer 11

poorly oxygenated blood flow to the lungs for gas exchange
inlet: pulmonary arteries
outlet: pulmonary veins

Question 12

where are the great vessels located

Answer 12

cranial mediastinum

Question 13

what is the name of the embryonic layer that lines the developing gut tube

Answer 13

endoderm

Question 14

what are the airways, lungs and visceral pleura derived from

Answer 14

visceral mesoderm and endoderm

Question 15

what are muscle, CT and cartilage derived from

Answer 15

visceral mesoderm

Question 16

what is internal epithelial lining and glands derived from

Answer 16

endoderm

Question 17

what is the pleural cavity derived from

Answer 17

coelom

Question 18

where is the horizontal fissure of the lungs

Answer 18

b/w the cranial lobe and middle lobe

Question 19

where is the oblique fissure of the lungs

Answer 19

b/w middle lobe and caudal lobe

Question 20

what is the cardia notch

Answer 20

a gap where the cranial and middle lung lobes don’t cover the heart

Question 21

what type of epithelium is found at the mucosa layer and what 3 cell types

Answer 21

respiratory epithelium
- ciliated cells
- goblet cells
- basal cells

Question 22

what is the Lamina Propria and where is it found

Answer 22

it is a layer of highly vascular loose CT
- has mucous and seromucous glands
**primary site of immune response (lymphocytes+neutrophils)

Question 23

what happens to the epithelium as the tracheobronchial tree branches out

Answer 23

it gets shorter and thinner closer to alveoli

lose goblet cells then ciliated cells

Question 24

what do basal cells become

Answer 24

basal cells –> club cells –> type II alveolar cells

Question 25

characteristics of the smooth layer of epithelium

Answer 25

• smooth muscle
• bronchoconstriction
• parasympathetic innervation

Question 26

the mucosa layer is comprised of what two things

Answer 26

epithelium lining
lamina propria

Question 27

layer of tissues that is characterized by dense, irregular fibroelastic CT and mucus and seromucous glands

Answer 27

submucosa

Question 28

cartilage layer

Answer 28

hyaline cartilage support
adventitia

Question 29

characteristics of club cells

Answer 29

• dome shaped
• no cilia
• secretory granules provide protection from pollutants + prevent luminal adhesion (collapse)

Question 30

what is the anatomical unit of gas exchange

Answer 30

alveolus

Question 31

site of blood-air barrier

Answer 31

alveolar septum

Question 32

what cells are found in the alveoli and what are their functions

Answer 32

type I alveolar (pneumocyte): gas exchange
- makes up 95% of alveolar surface

type II alveolar: secrete surfactant and regenerate the epithelium

alveolar macrophages