anaphy respi part 2

Main Bronchi

• Formed by division of the trachea

• Divides at the level of carina

• Each bronchus enters the lung at the hilum (medial depression)

Right bronchus

is wider, shorter, and straighter than left

Lungs

Occupy the entire thoracic cavity except for the central mediastinum

Base rests on the diaphragm

Serosa

covers the outer surface of the lungs

Pulmonary (visceral) pleura

covers the lung surface

Parietal pleura

lines the walls of the thoracic cavity

Pleural fluid

• fills the area between layers

• Allows the lungs to glide over the thorax

• Decreases friction during breathing

Pleural space

• between the layers

• is more of a potential space

Bronchial Tree

• Conduits to and from the respiratory zone

• Main bronchi subdivide into smaller branches and eventually into bronchioles

Alveoli

Simple squamous epithelial cells largely compose the walls

Alveolar pores connect neighboring air sacs

Stroma of lung

• is elastic connective tissue

• scaffolding/backbone structure of the lungs

Alveolar macrophages ("dust cells")

Add protection by picking up bacteria, carbon particles, and other debris

Surfactant-secreting cells

• maintain surface tension in alveol

• prevents alveoli from collapsing when deflating kapag nag-exhale

Pulmonary ventilation

moving air into and out of the lungs (commonly called breathing)

External respiration

• gas exchange between pulmonary blood and alveoli

• Oxygen is loaded into the blood

• Carbon dioxide is unloaded from the blood

Respiratory gas transport

transport of oxygen and carbon dioxide via the bloodstream

Internal respiration

gas exchange between blood and tissue cells in systemic capillaries

Diaphragm

is the major muscle for inspiration

inspiration (inhalation)

• Intrapulmonary volume increases

• Gas pressure decreases

• Air flows into the lungs

Expiration

• Intrapulmonary volume decreases

• Gas pressure increases

• Gases passively flow out to equalize the pressure

Forced expiration

can occur mostly by contraction of internal intercostal muscles to depress the rib cage