exchange surfaces Flashcards
describe what happens as you breathe in
air enters trachea
trachea splits into 2 bronchi, one bronchus to each lung
each bronchus branches off into smaller tubes called bronchioles
the bronchioles end in small air sacs called alveoli where gases are exchanged
what do the goblet cells do?
they secrete mucus, the mucus traps microorganisms and dust particles in the inhaled air, stopping them from reaching the alveoli
what do the cilia do?
beat the mucus, this moves the mucus upward away from alveoli towards through where its swallowed, this prevents lung infection
what do the elastic fibres do?
help the process of breathing out
what do the smooth muscle do?
allows their diameter to be controlled, during exercise the smooth muscle relaxes, tubes widen, less resistance to airflow
what do the rings of cartilage do?
provide support and is flexible to stop the trachea and bronchi collapsing when u breathe in and the pressure drops
which part of the lung has a large c shaped pieces of cartilage, smooth muscle, elastic fibres , goblet cells and ciliated epithelium
trachea
which part of the lung has a smaller pieces of cartilage, smooth muscle, elastic fibres , goblet cells and ciliated epithelium
bronchi
which part of the lung has no cartilage, smooth muscle, elastic fibres , goblet cells and ciliated epithelium
larger bronchiole
which part of the lung has no cartilage, smooth muscle, elastic fibres and ciliated epithelium
smaller bronchiole
which part of the lung has no cartilage, elastic fibres no ciliated epithelium
smallest bronchiole
which part of the lung has no cartilage, elastic fibres and no ciliated epithelium
alveoli
explain the process of inspiration
the external intercostal and diaphragm muscles contract
this causes the ribcage to move upwards and outwards, and the 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
ITS AN ACTIVE PROCESS, REQUIRES ENERGY
explain the process of expiration
the external intercostal and diaphragm muscles relax
ribcage move inwards and downwards and the diaphragm becomes curved again
thorax volume decreases, causing the air pressure to increase
air is forced out of the lungs
normal expiration=passive process
forced expiration=active process
define tidal volume
the volume of air in each breath
define vital capacity
the maximum volume of air that can be breathed in or out
define breathing rate
how many breaths are taken usually in a minute
define oxygen consumption or O2 uptake
the rate at which an organism uses up oxygen
why is soda lime used in a spirometer?
it absorbs carbon dioxide so theirs only oxygen in the chamber which the subject inhales from
what is a counter current system in fish?
when blood flows through the gill plates in one direction and water flows over in the opposite direction, it maintains a large concentration gradient between the water and the blood,
conc of O2 in water is always higher than that of blood so as much O2 diffuses from water into blood
what do the gill plates have to speed up diffusion
lots of blood capillaries, thin branches called gill filaments and thin surface layer of cells
describe fish ventilation
fish opens mouth lowering the floor of the buccal cavity.
volume of the buccal cavity increases decreasing the pressure inside the cavity
water is sucked into the cavity
how does air move into the tracheae in an insect?
through pores on the insects surface called spiracles
what movement do insects use to change the volume of their bodies and move air in and out of the spiracles
rhythmic abdominal movements
why do multicellular organisms need exchange surfaces?
there is a big difference between some cells and the distance between them and the outside environment
larger animals have a smaller SA:VOL, its difficult to supply a large volume of animal through a relatively small outer surface
they have a high metabolic rate so they use up O2 and glucose faster
how are root hair cells adapted to improve their efficiency
the cells on plant roots grow into long hairs, which stick out into the soil, this gives roots a large surface area which helps to increase the rate of absorption of water and mineral ions from the soil
how is the alveoli adapted to improve their efficiency
each alveolus is made from a single layer of thin flat cells called the alveolar epithelium
surrounded by a large capillary network giving each alveolus its own blood supply, blood constantly takes away oxygen and brings CO2, these features help maintain the conc gradient
how are fish gills adapted to improve their efficiency
fish gills contain a large network of capillaries so they are well supplied with blood
well supplied with blood-fresh water constantly passes over them
