Exchange surfaces & Breathing Flashcards
What is the function of Goblet cells?
Secrete mucus that traps microorganisms inhaled in the air
What is the function of the Cilia?
Moves the mucus and trapped microorganisms away from alveoli, helping prevent lung infections
What is the function of Elastic fibres in the gaseous exchange system?
Help process of breathing out, (lungs inflate and fibres are stretched, and recoil to push out air when exhaling)
What is the function of Smooth muscle?
Control diameter of Trachea, Bronchi, Bronchioles. In exercise, it relaxes, widening tube so air can get in/out easier
What is the function of the rings of cartilage?
In walls of trachea and bronchi and provide support, sp trachea doesn’t collapse when you breathe in and the pressure drops
Describe the cartilage present in the trachea
Large C-shaped pieces
What happens in Inspiration?
AIR FLOWS IN
- Volume of thorax increases, decreasing pressure
- Internal intercostal muscles contract causing ribs to
move upwards and outwards
- Diaphragm muscles contract, causing diaphragm to
move downwards and flatten
What happens in Expiration?
AIR IS FORCED OUT
- Thorax volume reduces, air pressure increases
- External intercostal muscles relax, causing ribs to move
inwards and downwards
- Diaphragm muscles relax, causing diaphragm to become curved again
What is ‘Tidal volume’?
The volume of air in each breath
What is ‘Vital capacity’?
The maximum volume of air that can be breathed in/out
What is ‘Breathing rate’?
How many breaths are taken, usually in a minute
What is ‘Oxygen consumption/uptake’?
The rate at which an organism uses up oxygen
What machine can be used to investigate breathing?
A Spirometer
Why are root hair cells a good example of an exchange surface with a large surface area?
Each root has millions of these hair cells that give the root a large surface area to increase rate of absorption of water
Why are the Alveoli a good example of a thin exchange surface?
Each one is made of a single layer of thin flat cells (Alveolar Epithelium)
Thin cells help decrease the diffusion distance for the 02 and CO2, increasing the rate of diffusion
Why are the Alveoli a good example of an exchange surface with a good blood supply?
Alveoli are surrounded by a large network of capillaries to give each one its own blood supply, taking oxygen away and bringing more CO2, helping maintain conc. gradient
Which types of organisms need specialised exchange systems?
Large multicellular organisms
Why do multicellular organisms need Transport Systems?
- Low SA:V ratio, higher metabolic rate
- Active = Large number of cells respiring v. quickly
- Diffusion won’t meet needs of cells constantly requiring
oxygen
How does the circulatory system work in fish?
Heart pumps deoxygenated blood to gills to pick up oxygen, then on through the rest of the body, and back do the heart, deoxygenated
Describe an open circulatory system?
- Heart is segmented, it contracts in a wave, pumping
blood into a single main artery - Artery opens up into the body cavity
- Blood flows around insects organs, making way back to
heart segments through series of valve
Describe the structure of a Capillary
A layer of Endothelium one cell thick
Describe the structure of a Vein
- Large lumen
- THIN muscle wall
- Endothelium
Describe the structure of an Artery
- Folded Endothelium
- THICK muscle layer
- Elastic tissue in wall
How is tissue fluid formed?
- At start of capillary bed, nearest arteries, hydrostatic pressure inside capillaries is greater than in the tissue fluid
- This difference forces fluid out of capillaries into spaces around the cells = forming tissue fluid
Where does excess tissue fluid drain?
Into the Lymph system
Why are Red blood cells only in the blood?
They’re too big to get through capillary walls into tissue fluid
Why are no/very few white blood cells in the tissue fluid?
Because the only enter tissue fluid when there’s an infection
