All Module 3 Flashcards
How do substances diffuse in a single celled organism
What is the diffusion rate in a single celled organism
How do substances diffuse in a multicellular organism
What is the diffusion rate in a multicellular organism
In a single celled organism it diffuses directly into the cell.
The diffusion rate is quick in a single celled organism
In multicellular organism diffuse slowly because some cells are too deep within the body - too far from the surface
The diffusion rate is slow in multicellular organisms
What type of special features do exchange surfaces have.
Eg. Alveoli
A large surface area
Good blood supply/ ventilation
For alveoli it has a single layer of thin flat cells. The thin layer helps decrease the distance over which O2 and CO2 diffuse
Alveoli surrounded by a large capillary network, these feature help maintain concentration gradient
List what’s in the lungs
Trachea Rib cage Kung Diaphragm Intercostal muscles (internal and external) Bronchus Bronchiole alveoli
Explain what the:
Goblet cells
Cilia
Elastic fibres do
Goblet cells: line the airway, secrete mucus. Mucus traps microorganisms and dust particles. Stopping them from reaching the alveoli
Cilia : on surface of cells lining airway. Beat mucus. Moves mucus upwards. Prevents lung infection
Elastic fibres : in walls of trachea, bronchi, bronchioles + alveoli. Help process of breathing out. Stretches outwards when inhale. Recoils back during exhalation
Explain what the:
Smooth muscles
Rings of cartilage do
Smooth muscle: in walls of trachea, bronchi + bronchioles. Allows their diameter. During exercise smooth muscles relax. Making tubes wider
Rings of cartilage: in walls of trachea and bronchi provide support. Stops trachea + bronchi collapsing
What is inspiration
External intercostal + diaphragm muscles contract.
Cause rib cage to move up + out
Diaphragm flatten, increasing the volume of thorax ( space where lungs are)
Volume of thorax increases = lung pressure decreases
Causes air to flow into the lungs
Inspiration is an active process - it requires energy
What is expiration
External intercostal + diaphragm muscles relax
Rib cage moves down + in
Diaphragm curves
Thorax volume decreases = air pressure increases
Air forced out of lungs
Expiration = passive process
What is a spirometer
It’s an oxygen-filled chamber with a movable lid
It’s to give readings of tidal volume, vital capacity, breathing rate and oxygen uptake
What system do fish use for gas exchange
A counter-current system
Explain the process of a counter-current system for gas exchange in fish (pt 1)
1) Water, containing onygen, enters the fish through its mouth and passes out through the gils
2) gill is made of lots of thin branches caled gill filaments/ primary lamellar, which give a big surface area for exchange of gases The gill filaments are covered in lots of tiny structures called gill plates or secondary lamellae, which increase the surlace area even more. Each gill is supported by a gill arch.
3) The gill plates have loes of blood capillaries and a thin surface layer of cells to speed up diffusion
Explain the process of a counter-current system for gas exchange in fish (pt 2)
4) Blood flows through the gill plates in one direction water flows over in the opposite direction This is called a counter-current system, It maintains a large concentration gradient between the water and the blood. The concentration of oxygen in the water is always higher than that in the blood, so as much oxygen as possible diffuses from the water into the blood.
How do fish gills ventilate
1) The fish opens its mouth, which lowers the floor of the buccal cavity ithe space inside the mouth. The volume of the buccal cavity increases decreasing the pressure inside the cavity. Water is then sucked in to the cavity
2) When the fish closes is mouth the floor of the buccal cavity is raised again. The volume inside the cavt decreases, the pressure increases, and water is forced out of the cavity across the gill filaments
3) Each gill is covered by a bony flap called the operculum iwhich protects the gill. The increase in pressure forces the operculum on each side of the head to open, allowing water to leave the gills
