1. Flashcards
Breathing:
mechanical process where air moves in and put out the lungs
Gaseous Exchange:
Oxygen and carbon dioxide go across a gaseous exchange surface
Cellular Respiration:
gradual release of energy from organic compounds with O2 present
Necessities of Gaseous Exchange:
》respiratory system is to absorb O2 from atmosphere making it available to cells for respiration
》CO2 is released by cells during respiration and is continously removed during gaseous exchange
》CO2 concentration in the body can dangerously lower the pH in bodily fluids
Requirements for an effective gaseous exchange system:
》must be large to maximise gaseous exchange
》thin- quick and easy diffusion
》moist- O2 & CO2 must be in a solution so it can be diffused through a surface
》transport system- efficient transport of gases
》well protected- fragile & thin
Human Gaseous Exchange:
What do the air passages do and consist of?
》transportation of air to and from lungs
》nasal passages, pharynx, trachea, bronchi, bronchioli
What are the nasal cavities and what do they do?
》the 2 external nostrils lead to the 2 nasal cavities that are separated by a septum
》small hairs in the nasal cavities filtration largest particles from inhaled air
》they are divided into 3 passages by 3 curved turbinate bones
》lined with a mucous membrane (ciliated columnar epithelial cells)
• richly supplied with superficial blood capillaries that warm incoming air
What are goblet cells?
》secrete mucous
》traps dust and germs
》an antiseptic and prevents inhaled germs from multiplying
》moistens incoming air and prevent gaseous exchange surfaces from drying out
What do the cilia do?
》perform sweeping movements in the direction away from lungs, therefore dust carrying mucus is expelled to the outside
Pharynx:
》nasal cavities open into pharynx
》has 2 openings:
• glottis leading to the trachea
• oesophagus aka gullet
Trachea:
》a long, tubular structure (+/- 12cm) infront of the oesophagus
》larynx aka voice box houses the vocal chords which is located at the top of the trachea
》lined with ciliated columnar epithelial tissue that secrete mucus
》C-shaped cartilage rings
• covered with involuntary muscle tissue
Larynx:
》a 🔺️ cartilage box
》top of larynx, a thin leaf-shaped structure (epiglottis)
What does the epiglottis do?
》closes the glottis during swallowing
》prevents food from entering the trachea and choking
How does the involuntary muscle assist the oesophagus?
allows it to expand when food moves down
What happens when dust particles and germs enter trachea?
trapped in mucus and is moved to the pharynx by a sweeping action of cilia = coughing or swallowing
How is the trachea divided?
》Into the R and L bronchus
》entering the R and L lung
What is the bronchi lined with?
a mucous membrane
What are the bronchi held open by?
O-shaped cartilage rings
What does the bronchi divide into?
smaller branches
What happens when they become smaller branches?
they lose their cartilage and form bronchioles
Group of alveoli:
infundibulum (each bronchioli ends with one)
Adaption:
Nasal cavities have hairs
Function:
filters larger dust particles from inhaled air
Adaption: AIR PASSAGES
Richly supplied with superficial capillaries
warms incoming air
Adaption:
Goblet cells that secrete mucus
》traps dust and germs
》antiseptic- prevents multiplication of pathogens
》moistens incoming air- prevention of G.E. drying out
Adaption:
Cilia perform sweeping movements
carries dust-and-germs-carrying mucus outside
Adaption:
Opening to the trachea walls supported by C-shaped cartilage rings
supports and keeps trachea open
Adaption:
‘Open’ sides of C-shaped rings in contact with oesophagus
ability to stretch its walls when ingesting food
EXTERNAL STRUCTURE:
Lungs
》surround and protected by 12 pairs of ribs
》intercostal found between ribs
》R lung- 3 lobes
》L lung- 2 lobes
》Spongy & elastic
What is each lung surrounded by?
a double membrane aka the pleura
What lies between the double membrane and its functionality?
》intrapleural fluid
》prevention of friction when contracting and expanding
Why are the lungs conical?
there is a dome-shaped muscle plate that is situated at the bottom, aka the diaphragm
What epithelial tissue is surrounded by the alveoli?
squamous