3.2 Transport In Animals (and some exchange surfaces and breathing) Flashcards
What substances do organisms need to survive?
Glucose
Oxygen
What substances do organisms need to get rid of?
Lactic acid
Urea
Carbon dioxide
How do small organisms obtain and get rid of substances?
Diffusion, phagocytosis and exocytosis
Why do small organisms not need an exchange system?
The substances reach all cells as they’re all in the external environment
How do large organisms obtain and get rid of substances?
An exchange system
Why do large organisms need an exchange system?
Not all cells are in an external environment as there is a low surface area to volume ratio
What features make a good exchange system?
Moisture
Rich blood supply
Thin membranes
Large surface area
What is inhalation?
Breathing in
What is exhalation?
Breathing out
What happens during human inhalation?
- Rib Cage muscles and diaphragm contract to move down and become flatter/raise displacing digestive organs
- The volume of the thorax increases
- The pressure in the chest cavity drops below atmospheric pressure
- Air is moved into the lungs
What is the thorax?
Thoracic/chest cavity
What happens during exhalation?
- The rib cage muscles and diaphragm relax pushing up the diaphragm from the organs and allowing the ribcage to fall
- The volume of the thorax decreases
- The pressure in the thorax and lungs increases rises above atmospheric pressure
- Air is moved out of the lungs
What is atmospheric pressure?
The pressure in the surrounding air
What is the importance of a large surface area in the lungs?
Provides more space for molecules to pass through. The individual alveoli are also covered with moisture
What is the importance of a barrier permeable to oxygen/CO2 in the lungs?
The plasma membrane readily allows the diffusion of oxygen and carbon dioxide as small and non-polar
What is the importance of a thin barrier in the lungs?
Reduces diffusion distances
How thick are the alveoli?
1 cell
What is the importance of a good blood supply in the lungs?
Maintains a steep concentration as brings/takes substances
What is the importance of ventilation in the lungs?
The air is consistently is being replaced
What is the process of air flow?
Mouth –> Trachea –> Bronchus –> Bronchioles –> Alveoli
How is a rich blood supply maintained in the lungs?
Capillaries run over the surface of alveoli
How is ventilation maintained in the lungs?
Surrounded by diaphragm and intercostal muscles
How is a large surface area in the lungs produced?
Many alveoli
What are the reasons for exchange systems?
- Large multicellular organisms need a breathing system
- Cells in centre of organisms would not receive any oxygen
- Need more energy/high metabolic rate
Describe the structure of the trachea
Supported by a layer of cartilage to hold open and prevent collapse however it is incomplete to allow bending when food is swallowed
Lined with ciliated epithelial cells /goblet cells
Describe the structure of the bronchus?
Extensions of trachea
Split in two (left and right)
Similar to trachea but smaller
Cartilage rings hold pipe open
Describe the structure of the bronchioles
1mm/less in diameter Smaller bronchi Held open by smooth muscles Contracted by smooth muscles Lined with a thin layer of epithelial cells
Describe the structure of the alveoli
Air sacs Where most gas exchange occurs 200-300 NM in diameter Made of thin layer epithelial cells Elastic fibres recoil allowing air to move out of the alveoli
What can the spirometer be used for?
the volume of gas breathed in and out
What happens to the trace on a spirometer when inspiring?
It goes down
What happens to the trace on a spirometer when expiring?
It climbs up
How do you find the volume of a single breath on a spirometer?
The peak of expiration to the low of inspiration
How is carbon dioxide absorbed in a spirometer?
Soda lime
What is the chamber filled with in a spirometer?
Oxygen
How are movements recorded from a spirometer?
The floating chamber lid moves as the person breathes. It is then recorded on a datalogger to produce a trace
What is the tidal volume?
The volume of air inhaled or exhaled in one breath usually measured at a rest