Exchange + Transport Flashcards
Why don’t single-celled organisms need specialised exchange systems?
Substances can diffuse directly into cell
Give 2 reasons why organisms need specialised exchange systems
- Some cells are deep in the body
- Large animals have low SA:V ratios so hard to supply all cells with small SA
- Multicellular organisms have high metabolic rate so substances used up faster
Give 2 adaptions of root hair cells
- Shape creates large SA to increase rate of absorption
- Thin walls reduce distance needed to move
State 2 adaptions of alveoli
- Thin, flat cells reduces distance for diffusion to occur
- Good blood supply maintains high conc. gradient
Describe the structures air travels through to get to the lungs
- As you breathe, air enters trachea
- Trachea split into 2 bronchi
- Each bronchus branches off into bronchioles
- Air enters alveoli at end of bronchioles
What is the function of goblet cells?
Secrete mucus to trap pathogens + dust
What is the role of cilia in your airways?
- Waft mucus upwards to prevent lung infection
What do elastic fibres allow for during breathing?
Allow for stretching and recoiling of alveoli
What is the function of smooth muscle in the respiratory system?
Controls tube diameters; relaxes to widen airways during excersise
Why are cartilage rings C-shaped?
To allow for flexibility
What is the function of cartilage rings around the trachea?
To support and prevent collapse of airways
What 2 muscles contract during inspiration?
External intercostal muscles and diaphragm
Describe the movement of the ribcage during inspiration
Up and out, to increase volume of thorax
How does the movement of the ribcage allow air to move into the lungs?
The increase in volume decreases air pressure so air is sucked in
Is inspiration a passive or active process?
Active process! Needs energy
What occurs to muscles during expiration?
External intercostal muscles + diaphragm relax
Describe the movement of the ribcage during expiration
Down and in
Why is air exhaled out of the lungs when the ribcage moves in?
Thorax volume decreases so air pressure increases and air is forced out of lungs
Does expiration require energy?
No
What is tidal volume?
The volume of air inhaled per breath
What is vital capacity?
The maximum volume of air breathed in or out
What is the breathing rate?
Breaths/minute
Define O2 uptake/consumption
The rate of usage of oxygen (per minute)
What is the role of soda lime in a spirometer?
To absorb CO2
