Exchange Surfaces Flashcards
(24 cards)
What is the relationship between body mass and metabolic rate?
The greater the mass of an organism,the higher the metabolic rate.
What is Basal Metabolic Rate (BMR)?
The metabolic rate of an organism when at rest. The BMR is significantly lower than when an organism is actively moving
What makes an efficient exchange surface?
- Large surface area
- Short diffusion distance (thin)
- Rich blood supply
- Ventilation
What is simple diffusion?
Passive movement of molecules from an area of high concentration to an area of low concentration.
Features of the alveoli.
- Walls are one cell thick and these cells are flattened allowing quicker gas exchange due to the short diffusion distance.
- Large number of alveoli increasing surface area available for oxygen and carbon dioxide to diffuse across.
- Extensive network of capillaries (also made up of one cell thick walls of flattened cells) allowing a constant flow of blood.
What is the process of Inhalation?
- Diaphragm contracts and moves downwards.
- External intercostal muscles contract moving the ribcage up and out.
- Cavity volume increases
- Pressure in the lungs decreases below atmospheric pressure
- Air moves into the lungs from an area of higher pressure to an area of lower pressure
What is the process of exhalation?
- Diaphragm relaxes and moves upwards
- External intercostal muscles relax,Internal intercostal muscles contract moving the ribcage down and in
- Cavity volume decreases
- Pressure in the lungs increases above atmospheric pressure
- Air moves out of the lungs from an area of higher pressure to an area of lower pressure
What is cartilage?
- Strong flexible tissue found in various places around the body
- e.g rings along the trachea (tracheal rings) helping to support the trachea keeping it open while allowing it to move and flex while we breathe.
What is ciliated epithelium
- Specialised tissue found along the trachea down to the bronchi
- Each cell has small projections of cilia which swaft/sweep mucus,dust and bacteria upwards and away from the lungs and the epithelium itself.
What are goblet cells?
- mucus producing cells that secrete viscous mucus which traps dust, bacteria and other microorganisms and prevents them from reaching the lungs.
- found scattered through the ciliated epithelium in the trachea.
- Swept along by the cilia and then swallowed where the mucus and microorganisms will be destroyed by the acid in the stomach.
What is a squamous epithelium?
- found in the lining of the alveoli to allow gas exchange.
- Creates a very thin alveolar wall and is permeable for gas exchange
What is the smooth muscle?
- Found throughout the walls of the bronchi and bronchioles
- Helps regulate the flow of air into the lungs by dilating when more air is needed and constructing when less air is needed.
What are elastic fibres?
- Present in all lung tissues
- Enable the lungs to stretch and recoil
- The ability to recoil makes exhalation a passive process.
What are capillaries?
- An extensive network of small,thin and narrow tubes that are only wide enough to allow one blood vessel to travel through at a time ensuring sufficient time and opportunity for gas exchange to occur.
- Surround every alveolus
- Carbon dioxide diffuses out of the capillaries,oxygen diffuses into the capillaries to be carried around the body.
What are mucus glands?
Glands that work with goblet cells in the trachea and bronchi to produce mucus.
What is the trachea?
- The channel that allows air to travel to the lungs.
- C-shaped cartilage rings ensure that the trachea remain open at all times.(They are C-shaped to prevent any friction from rubbing with the oesophagus located close behind)
- Its lined with ciliated epithelium
- The wall of the trachea contains smooth muscle and elastic fibres.
What is the bronchi?
- A channel that allows air to travel to the lungs.
- Similar to the trachea but have thinner walls and a smaller diameter.
- Have full rings of cartilage and can also form irregular blocks
What are bronchioles?
- Narrow self supporting tubes with thin walls
- Not usually supported by cartilage but can sometimes have some
- Lined with ciliated epithelium but don’t tend to have goblet cells
- Vary in size and structure, getting smaller as they get closer to the alveoli
- Larger bronchioles contain elastic fibres and smooth muscle that adjust the size of airway to change the airflow
What are alveoli?
- Located at the ends of bronchioles
- Alveolar wall consists of a single layer of squamous epithelium
- Elastic fibres are located in the extracellular matrix
- Have an extensive network of capillaries
- Watery fluid lines the alveoli facilitating the diffusion of gases.
What is vital capacity?
The maximum volume of air that can be breathed in and out
What is tidal volume?
The volume of air that is breathed in or out in one breath
What is a breathing rate?
The number of breaths taken in one minute (one breath = taking air in and breathing it back out again)
What is oxygen uptake?
The volume of oxygen used up by someone in a give time
