respiratory system

- everything needs to breathe

-oxygen=necessary for chemical reactions inside cell known as cellular respiration- break up nutrient from food such as sugars- set free energy-drive cells life process

- oxygen from air- 1/5 oxygen

- breathe air into our lungs- oxygen absorbed into the blood- sent around the body

-nose/throat/windpipe/two lungs=all involved in breathing = respiratory system

breathed in air flows through nose

small hairs filter out bits of dust and floating particles

sneezing clears dust particles from the nose

Windpipe- trachea

- divides into two main airways- bronchi=insides lined with sticky fluid, mucus-traps dirt and tiny hairs that propel mucus to top of windpipe where swallowed

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diaphragm

-chest filled by two lungs, heart and main blood vessels

- dome shaped muscle sheet that forms the base of chest and roof of abdomen

-main breathing muscle 

Nasal cavity

- air is warmed,cleaned by tiny hairs and moistened by mucus

- dust particles/pollen/germs can irritate nasal passage and cause you to sneeze- clearing it

Trachea(windpipe)

- held open by cartilaginous rings which prevent it from collapsing during breathing

- eppiglottus closes of the windpipe during swallowing to stop food

- if food does pass through and get caught in windpipe= choke/ cough to expel it

Bronchi and bronchioles

- trachea branches  into bronchi- one to each lung - then branck into smaller bronchioles

- directly connected to alveoli

The alveoli

- tiny hollow air sacs, supplied with cappilaries- either carry oxygen away to the body or bring carbon dioxide to be expelled from the body

The diaphragm

- muscular wall between the chest and the abdomen and joined to six lower ribs of rib cage

- whe contracts- flattens and bushes downwards- the ribs expand chest= sucking air into lungs from outside

- when breath out opposite happens= the diaghragm relaxes- pushing upwards- forcing air out of lungs