bio 2: respiratory system 1

what is the main fuel for cellular respiration

glucose

what does the respiratory saturate with oxygen

plasma and hemoglobin

pathway of air

nose/mouth → pharynx (throat) → larynx (voice box) → trachea → bronchi → bronchioles → alveoli

what do the lungs accomplish by being highly branched and terminating in hundreds of millions of alveoli

maximize surface area

what is the inner lining of the trachea covered in

mucus

what do the cilia in tracheal epithelial cells do

beat back and forth to move particles trapped in mucus up to be coughed out

what are bronchioles wrapped in

smooth muscle that contract to control airflow in the lungs

type 1 alveoli

flat like pancakes; O2 and CO2 diffuse across these

type 2 alveoli

secrete surfactant which reduces surface tension of water

how does gas move across pressure gradients in the lungs (low to high or high to low)

from high to low

when does inhalation occur

when the diaphragm and intercostal muscles contract

• increase volume → decrease pressure → air moves into lungs

when does exhalation occur

when the diaphragm and intercostal muscles relax

• decrease volume → increase pressure → air moves out

what percent of atmospheric air is oxygen

21%

what is the partial pressure of O2 at sea level

160 mmHg

how do O2 and CO2 diffuse across membranes

simple diffusion

what drives the diffusion of O2 into erythrocytes?

pressure gradients

pathway of O2 from alveolar space to hemoglobin

alveolar space → plasma → erythrocyte cytosol → bound by hemoglobin

by the time air reaches the alveoli, the PO2 of inspired air is…

a little over 100mmHg

why does O2 diffuse down its pressure gradient from the alveolar space into blood plasma

the PO2 in the alveolar space (100mmHg) is higher than PO2 in the plasma of deoxygenated blood in the lung capillaries (40mmHg)

The PO2 of the plasma and the erythrocyte cytosol are constantly reaching _____

equilibrium

how does high altitude cause altitude sickness

high altitude → decreases atmospheric pressure → decreases atmospheric PO2 → decreases alveolar PO2 → decreased PO2 gradient between alveolar space and blood → decreased O2 diffusion into the plasma from the alveoli

how many oxygens can one hemoglobin bind

4

what is hemoglobin composed of

4 globin subunits which binds heme groups which binds iron

what would you expect if there was no iron in hemoglobin

O2 wouldnt be able to bind