Structure of lungs 4.1

four point one

Explain how air enters the lungs

air enters through the mouth or nose, then travels down the pharynx and is diverted to the trachea by the epiglottis, passing over the larynx as it does, and finally into the two primary bronchi to deliver the air to each lung.

what is the nose lined with and what does it do

mucous membranes that warm the air, and hair and mucus that catch dust and debris

pharynx

the broad term for the nasal cavity to top of the trachea/oesophagus

epiglottis

flap of elastic cartilage that covers oespoahgus when inhaling, and the larynx when eating

oesophagus

where food goes

larynx

the cartilage that joins the pharynx and trachea

vocal cords

contained in larynx, mucous membranes that vibrate as air passes over them

Trachea/windpipe

made of c shaped cartilage rings
splits into two branches taking air into each lung

what lines the trachea

epithelial lining that produces mucus to trap dust and debris from entering lungs
cilia take the debris to the pharynx to be swallowed and digested

what are the 5 sections of the bronchi

primary bronchi - one per lung
secondary bronchi - air into each lobe of the lung
tertiary bronchi - further divisions
bronchioles - no cartilage, only smooth muscle
terminal bronchioles - millions, end of bronchi, no cartilage

what are the bronchi made up of

c shaped cartilage rings that get smaller and more spread apart with smooth muscle and elastin forming their structure
cilia and mucus are present to remove dust and debris

why do bronchioles not have cartilage

to control airflow and expand when lungs need more oxygen
cilia and mucus present

what is between the lungs

the mediastinum that contains the heart and blood vessels

how many lobes do the lungs have

left - 2
right - 3

what membrane lines the chest and lungs

pleura

what fluid is between the lungs and chest and what does it do

pleural fluid holds lungs against chest wall and allows them to slide while breathing

what is at the end of the terminal bronchioles

alveoli (alveolus singular)

what are alveoli

the surface for gas exchange

explain the structure of the alveoli

small wall that is 1 cell thick surrounded by capillaries
they’ve got bumps on them for higher SA:vol

ribs

framework and support for chest

intercostal muscles

muscles between the ribs that move them up and out during inhalation

diaphragm

separates chest and abdomen and flattens downwards during inspiration to make room

the process in which air is moved in and out of lungs

ventilation