L6 Resp Zone and Blood Supply

Question 1

4x components of Respiratory Zone

Answer 1

1. Respiratory bronchioles (limited gas exchange)
2. Alveolar ducts
3. Alveoli Sacs
4. Alveoli (individual)

Question 2

17th Generation of branching

Answer 2

Infection threshold crosses

end of conducting zone (defense against infection)

Question 3

Lobule

Answer 3

Tube supplied by a terminal bronchiole

Question 4

Acini

Answer 4

Supplied by respiraotry bronchiole (individual units)

related to lower regions and end of respiratory tree

Question 5

Difference between terminal and respiratory bronchiole

Answer 5

Respiratory bronchiole has small holes/buds of alveoli in the walls
-can start undergoing gas exchange

Question 6

Smooth Muscle in respiratory zone

Answer 6

Large elastic bands spiralling randomly around

+ elastic fibres

Question 7

Respiratory bronchiole epithelium

Answer 7

Simple Ciliated cuboidal epithelium
Majority of cells: Club/Clara cells
Thick. No gas exchange

Question 8

Club cells

Answer 8

Clara cells
Dome shaped
1) act as stem cells to regenerate the lower airways. 2) Secretory cells. Watery secretion to keep airways hydrated. secretions contain lipoproteins that prevent
a) luminal adhesion if the airway was to collapse.
b) anti-microbial properties.

Question 9

Efficient use of space in lung

Answer 9

No tube/airway
will be backed fill with alveoli tissue (filling space around tube)
-spongy= majority of surface area of lung is alveoli

Question 10

Alveolar Duct

Answer 10

Hallway with doors on either side
-Smooth muscle pegs (identifying feature)
-door frames of smooth muscle (entrances to alveoli)
Sometimes respiratory bronchiole will go straight into alveolar sac

Question 11

Type I Pneumocytes

Answer 11

95% Majority of alveoli SA
Squamous cells (thin barrier, faster diffusion rate)
Cytoplasm + nucleus
-bulk of air is exchanged

Question 12

Type II Pneumocytes

Answer 12

Surfactant cells
-5% of SA beucuase limited gas exhcange
-premature birth, Neonatal Resp. Distress Syndrome, babies born too early with insufficient Type II surfactant cells
Secrete Surfactant lining surface of all squamous cells = Decreased surface tension in alveoli
Ruffled Border
Contain busy/metbaolic lamallar cells (active function)

Question 13

Surfactant

Answer 13

Type II surfactant cells
Secrete Surfactant lining surface of all squamous cells
-phospholipid
1) = Decreased surface tension in alveoli
=want to keep alveoli relatively open (lil recoil via elastic). avoid extra energy to reinflate millions of alveoli
2) + moist walls of alveoli. so if alveoli do collapse surfactant makes it much easier to reinflate
3) Reduces work of breathing

Question 14

Alveolar Macrophages

Answer 14

Last defence
-important in heart failure
Wandering cells /Dust cells
(pac man) Phagocytose/consume/chop up debris (impaired muco-ciliary clearance. fine carbon particles in smog/industrial area)
-never get rid of some carbon particles
1) macrophages work upwards and get trapped in mucus and removed/broken down
2) wander into Inter-alveolar Septa and sit forever sitting with black fibres

Question 15

Alveolar Septa/walls

Answer 15

contains connective tissues

a) collagen: support capillary entrance and exit + alveoli
b) elastin: expand + elastic recoil to push air out through
- fibrotic lung disease

Question 16

Diffusion distance

Answer 16

0.5 microns

endothelium + alveolar epithelium type I + some surfactant

Question 17

Lamalar bodies

Answer 17

Increased contents/busyness= increased metabolic activity

-characteristic of secretory cells/esp. surfactant

Question 18

Fibrotic lung disease

Answer 18

increased collagen
= thicker and stiffer
=harder to inflate alveoli
= increased diffusion distance for air
(more hypoxic - higher partial pressure gradient in alveoli)

Question 19

Emphesema

Answer 19

Decreased elasticity in lung
1) Inflammatory Enzymes: stimulates by noxious particles (smoking)
=destroys elastin and collagen
a)=reduces recoil
= air get trapped, cant push air out (no Smooth muscle)
=barrel chest
b) =decreased SA available for gas exchange
=destruction of interalveolar septa (one big grape)

Question 20

Pulmonary Circulation

Answer 20

DEO blood into lungs –> heart –> OX blood out of lungs
Low pressure
Short system
Bulk flow of gases
1) Large/same size Pulmonary artery w. bronchus (O2 poor, large, low pressure) (thin wall and large lumen)
-narrows simulatenously with branching
2) less second to get through capillary to get oxygenated
3) Ct septa through bronchopulomanary segments
4) branch of pulmonary vein through lung parenchyma thin sheets of CT
5) hilum

Question 21

Systemic Circulation

Answer 21

Bronchiole circulation
Blood supply for metabolic need of mucus production, cilia beating
-in walls of airway
-smaller (micro)
-Artery –> Capillary –> Vein (Bronchial + Azygous)

Question 22

Pulmonary artery vs Pulmonary vein

Answer 22

Location
-pulmonary artery always next to airway
-shared CT
Vein: lonely

Question 23

Pulmonary and Systemic Anastomoses

Answer 23

Bronchopulmonary anastomoses b/w
1. Bronchial arteries (oxygenated) + Respiratory Bronchiole’s P arteries
2) Systemic Capillaries + Pulmonary Veins (Ox)
-decreases partial pressure of O2 down. important for respiratory drive
=mixed venous blood

Question 24

Pulmonary Circuit Function, Arteries, Veins + Pressures

Answer 24

Function: conducting
Arteries: next to bronchi
Vein: in parenchyma
Pressures: arteries: 25-15mmHg. vein: 5-0mmHg

Question 25

Systemic Circuit Function, Arteries, Veins + Pressures

Answer 25

Function: supply tissue of lung with O2 + remove CO2
Arteries: in walls of airways
Vein: anastomose –> drain into azygous
Pressures: arteries: 120-80mmHg —> 40mmHg. vein: