Breathing Flashcards
Explain Inspiration?
dome shaped diaphragm contracts, flattening and lowering.
external intercostal muscles contract moving the ribs upwards and outwards.
Volume of the thorax increases, pressure is reduced .
Lower pressure than atmospheric air allows air to enter .
How is breathing controlled?
chemoreceptors in the medulla is sensitive to concentration of carbon dioxide in the blood.
if concentration is high, nerve impulses sent to the diaphragm to increase breathing rate.
Lungs expand, stretch receptors, send impulses to the expiratory centre.
Inspiratory system switches off, stretch receptors not stimulated, become inactive.
Role of the nasal cavity?Features?
large surface area with a good blood supply.
Warms air to body temperature.
Hairy lining and secretes mucus to trap dust and bacteria to protect delicate lung tissue from irritation and infection.
Role of the Trachea?Features?
main airway carrying clean, warm, moist air into the chest.
supported by incomplete rings if strong, flexible cartilage, stop it from collapsing.
rings are incomplete so oesophagus can sit behind.
lined with ciliated epithelium and goblet cells between and below epithelial cells.
What are goblet cells?They work with cilia how?
they secrete mucus into the lining of the trachea to trap dust and microorganisms that escape the nose lining.
Cilia beat and move the mucus along with dirt and microorganisms.
What is the bronchus?
in the chest.
Divides to form left and right bronchi.
similar to the trachea but smaller.
What are bronchioles?
In the lungs.
Bronchi divide to form many small bronchioles.
Diameter < 1mm, contain no cartilage.
Walls contain smooth muscle, when muscle contracts bronchioles constrict.
Lined with thin layers of epithelium, making some gaseous exchange possible.
What is the alveoli?Role?
tiny air sacs, main gas exchange surfaces of the body.
diameter of 200 to 300um.
consists of a thin layer of flattened epithelial cells, along with collagen and elastic fibres.
Elastic tissue allow alveoli to stretch.
They help to squeeze air known as elastic recoil of the lungs.
How is oxygen dissolved in the alveoli?
inner surface of the alveoli is covered in a solution of water, salt and lung surfactant. Surfactant makes it possible for alveoli to remain inflated. Oxygen dissolves in water before diffusing in the blood.
What is a spirometer?What does it do?
a device thats measure oxygen taken in. a chamber filled with oxygen on a tank of water. breathing out causes thenlid to float up. movement is recorded via a data logger.
How do insects perform gas exhange?
small opening called spirales allow air to enter and leave also water vapour. spiracle leads to the tracheae which are lined with spirals of chitlin.Chitlin is imprermeable to gases. Tracheae branch to form smaller tracheoles, have no chitlin so are permeable to gases. Tracheoles are small and run between cells so a lot of gas exchange takes place.
How do gases move through the tracheloles?
diffusion.
What is tidal volume?
volume of air that moves into and out of the lungs with each resting breath.
Its about 500cm3 in most adults at rest.
About 15% if the vital capacity
Vital capacity?
is the volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible intake if breath.
Inspiratory reserve volume?
the Max volume of air you can breath in over and above a normal inhalation
