Module 3 Exchange And Transport Flashcards
Diffusion
Movement of particles from an area of high concentration to an area of low concentration
Osmosis
Movement of water from an area of high water potential to low water potential across a semi permeable membrane.
Active transport
Movement of particles from an area of low concentration to high concentration which require energy.
What is an exchange surface
A specialised area that is adapted to make it easier for molecules to cross from one side of surface to other
What is better for gas exchange, low or high surface to volume ratio
High
What are features of efficient gas exchange
Large SA, thin layers, blood supply(maintains large diffusion gradient), moist(allow gases to be dissolved, faster exchange), ventilation(maintains diffusion gradient), temperature(hotter particles move quicker).
Equations for sphere
Volume= 4/3 x pie x r^3. SA= 4 x pie x r^2
Equations for cuboids
Volume= length x width x height. SA= (4 x length x height) + (2 x height x width)
Equations for cylinders
Area of a circle= pie x r^2. Volume= pie x r^2 x h. SA= (2 x pie x r x h) + 2 x pie x r^2
Why do multicellular organisms need a exchange surface and single celled don’t
Single celled have a shorter diffusion distance due to single cell, whereas, multicellular have a high metabolic rate so use oxygen and glucose faster aswell smaller SA and longer distance of diffusion.
What is the better word than amount
Volume
What precautions should you take with a spirometer
Person is sitting down so they don’t faint, single use mouthpiece
Why might scientists record lung volumes
Test for health issues
What is the purpose of soda line in the canister attached to breathing tubes
Absorbs carbon dioxide
Why might a person using a spirometer to measure tidal volume wears a nose clip
Valid measurements of breaths through the mouth and not nose
Ventilation
Inspiration(breathing in) and expiration( breathing out), controlled by movements of diaphragm, intercostal muscles, ribcage
What happens during inspiration
External intercostal and diaphragm muscles contract. Causes ribcage to move upwards and outwards and diaphragm to flatten, increasing the volume of the thorax. As the volume of the thorax increases the lung pressure decreases. This causes air to flow into the lungs. Inspiration is an active process, requires energy.
What happens during expiration
The external intercostal and diaphragm muscles relax. The ribcage moves downwards and inwards and the diaphragm becomes curved again. Thorax volume decreases,causing air pressure to increase. Air is forced out of the lungs. Normal expiration is a passive process, doesn’t require energy. Can be forced though, internal intercostal muscles contract, to pull ribcage down and in.
Tidal volume
The volume of air in each breath, about 0.4dm^3
Vital capacity
The max volume of air that can be breathed in and out
Breathing rate
How many breaths are taken per unit time (usually per min)
Oxygen uptake
The rate at which a person uses up oxygen
How to use a spirometer
Person breathes through a tube connected to the oxygen chamber. As the person breathes in and out, the lid of the chamber moves up and down. These movements are recorded by a pen attached to the lid of the chamber, spirometer trace, or hooked up to a motion sensor. The soda lime in the tube absorbs carbon dioxide.
Why does the total volume of gas in the chamber decrease over time
Air breathed out is a mixture oxygen and carbon dioxide. Carbon dioxide is absorbed by the soda lime, only oxygen in chamber which subject inhales (by respiration).
Why do fish have special adaptions
There is lower concentration of oxygen in water than in air
Structure of gills
Water, containing oxygen, enters the fish through its mouth and passes out through the gills. Each gill is made of lots of thin plates called gill filaments or primary lamellae which gives a big surface area for exchange of gases(increase rate of diffusion). The gill filaments are covered in tiny structures called gill plates or secondary lamellae, which increase the surface area even more. Each gill is supported by a gill arch. The gill plates have lots of blood capillaries and thin surface layer of cells to speed up diffusion between the water and the blood.
Counter current system
In the gills of a fish, blood flows through the gill plates in one direction and water flows over in the opposite direction. The counter current system means that the water with a relatively high oxygen concentration always flows next to blood with a lower concentration of oxygen. This means a steep concentration gradient is maintained between water and blood, better diffusion.
Ventilation in fish
Fish opens its mouth, which lowers the floor of the buccal cavity. The volume of the buccal cavity increases, decreasing pressure inside the cavity. Water is sucked in to cavity. When the fish closes its mouth, the floor of the buccal cavity is raised again. The volume inside the cavity decreases, pressure increases, water if forced out of cavity across gill filaments. Each gill is covered by a bony flap called the operculum. The increase in pressure forces the operculum on each side of the head to open, allowing water to leave the gills.
Dissecting fish
Place fish in a dissection tray, push back operculum and use scissors to carefully remove the gills, cut each gill arch through the bone at the top and bottom, you should be able to see gill filaments.
What safety to remember with dissections
Wear a lab coat, clean tools, sharp tools, gloves
The features of the trachea
Large c shaped pieces of cartilage, smooth muscle, elastic fibres, goblet cells, ciliated epithelium
