M3 chapter 7 Exchange surfaces and breathing Flashcards
in what type of cell is the SA:V smaller?
in larger cells
what is the trachea surrounded by?
16-20 rings of hyaline (c-shaped) cartilage which provide support to prevent it collapsing
what else supports the trachea?
Ligaments connect the rings. a smooth muscle known as the trachealis muscle bridges the gap between the ends of the incomplete rings and runs along the back wall of the trachea.
what is the trachea lined with?
lined by ciliated pseudostratified columnar epithelium
what do goblet cells do?
release and create a mucus between the CPCE, which helps trap microorganisms
how does the trachea trap and destroy pathogens?
mucus traps the pathogens and the cilia beat the mucus up in to the oesophagus to go to the stomach to be destroyed
where are the brochi?
trachea branches into left and right bronchi at the 4th thoracic vertebra
what happens after the trachea branches into left and right bronchi?
the primary bronchi enters the lungs at a point called the hilum and branch into secondary bronchi as they get narrower, which then branch into tertiary bronchi
what happens to the tertiary bronchi as they get narrower?
they become bronchioles which rely in elastic fibres that are attached to the surrounding lung tissue , as they get smaller they become terminal bronchioles which become respiratory bronchioles.
what do respiratory bronchioles do?
these deliver air to the alveoli for gas exchange
why is there an indentation on the left lung?
the heart sits just under the left lung creating an indentation called the cardiac notch
what type of epithelium do the bronchioles have?
start having simple ciliated columnar epithelium, this then changes to simple cuboid epithelium
what adaptation do the alveoli have to them to help diffusion?
they have a moist lining inside them called a surfactant which keeps the alveoli inflated and allows gases to dissolve in.
what are the lungs enclosed in?
a pleural sac which contains pleural fluid to allows inner and outer walls to slide over each other without causing friction during breathing
what is ventilation?
the movement of air into and out of the lungs to supply oxygen to the body and remove carbon dioxide.
where is the diaphragm and what is it controlled by?
muscle which sits near the bottom of the chest and is controlled by the phrenic nerve where it is under autonomic control
what are the 3 openings in the diaphragm?
caval opening (vena cava)
aorta
oesophagus
describe the process of inhalation?
the external intercostal muscles contract whereas the internal ones relax, as a result cause the ribs to raise upwards. The diaphragm contracts and flattens. This causes the volume inside the thoracic cavity to increase, this lowers the pressure. The difference between the pressure inside the lungs and atmospheric pressure creates a gradient, causing the air to enter the lungs