Sec 30.2: Respiration & Gas Exchange Flashcards
What does cellular respiration require? What does it produce?
It requires O2 and produces CO2 as a waste product
What is gas exchange?
It is an autonomic function that occurs in the alveoli and their capillaries and is regulated by the medulla & pons in the brain stem
What are the 3 principles that gas exchange is based on?
- O2 & CO2 are carried by the blood
- Gases move by diffusion from an area of higher concentration to an area of lower concentration
- The lining of the alveoli must be moist to help gases diffuse.
What are the characteristics of alveoli?
- 1 alveolus is about the size of a grain of sand
- all together give lungs a surface area of 100 meters squared, which allows lungs to extract enough O2
- they are surrounded by capillaries that contain lower concentration of O2
How do gases diffuse between alveoli and their surrounding capillaries?
O2 diffuses from alveoli (high conc.) to capillaries (low conc.)
CO2 & water, aka carbonic acid, a waste product produced by every cell, diffuse from capillaries (high conc. in blood) to alveoli where they are separated into CO2 and water again then exhaled
What do capillaries contain? And what are they?
They contain red blood cells, which are a type of cell that picks up oxygen in the lungs and delivers it to body cells
What do O2 molecules bind to?
They bind to hemoglobin, which is an iron-rich protein that can bind to 4 O2 molecules and gives blood its reddish-brown color
What is a cause of blood toxicity?
When CO binds irreversibly to hemoglobin
How do the medulla and pons regulate gas exchange?
They monitor dissolved gases in the blood - particularly CO2 concentrations
What is the medulla’s role in gas exchange?
Sensors in the respiratory and circulatory systems signal change to brain stem, so medulla sends messages through the nervous & endocrine systems that stimulate the diaphragm & rib cage muscles to work harder
It also regulates depth and frequency of breath based on activity
How does the level of activity change the blood acidity?
The more activity, the higher the level of CO2 in the blood, and the more acidic the blood becomes.
What is the leading cause of respiratory diseases?
Smoking, as it results in lung cancer, emphysema, etc.
What can the chemicals in tobacco smoke do?
They can paralyze cilia, damage alveoli, and cause genetic mutations that lead to cancer.
What are 3 examples of respiratory diseases?
Emphysema, Asthma, and Cystic Fibrosis
What is emphysema?
It is a lung disorder, caused mainly by smoking, where many alveoli are destroyed, gradually reducing the surface area for gas exchange = not enough oxygen can enter the blood.
