lab 6`

what is pulmonary ventilation?

the movement of air into and out of the lungs.

how does air move in respiratory system?

via the contraction and relaxation of respiratory muscles that create changes in the volume of the thoracic cavity

pressure gradients between the lungs and the atmosphere dictate what?

the direction that air will flow in

air flows from an area of ___________ to an area of ____________

air flows from an area from high pressure to an area of low pressure

what happens when intrapulmonary pressure is lower than atmospheric pressure?

air flows INTO the lungs AKA inspiration

what happens in expiration? what about intrapulmonary and atmospheric pressures

intrapulmonary is higher than atmospheric pressure → air flows out

what happens during quiet inspiration?

the diaphragm and external intercostal muscles contract → this expands thoracic cavity and lowering the pressure in lungs so air can go in.

what happens in quiet expiration?

the inspiratory muscles relax and the elastic recoil of the lungs and the thoracic wall decreases the lung volume. intrapulmonary pressure increases and that drives it to push air out

what happens in forced inspiration?

we use additional muscles like the sternocleidomastoid, scalenes and pectoralis minor to further expand the thorax → creating an even lower intrapulmonary pressure

what happens in forced expiration?

we use additional muscles such as the internal intercostals and abdominal muscles to compress the thoracic cavity → creating higher intrapulmonary pressure to move more air out

what is tidal volume?

the amount of air moved in a normal breath → normal quiet inspiration and expiration

what is the average tidal volume?

~500mL

what is inspiratory reserve volume IRV?

this is the extra air that we can inhale beyond TV

what is expiratory reserve volume ERV?

this is the extra air that we can expire beyond TV

we can combine IRV and ERV to form what?

respiratory capacities!

what is vital capacity VC?

the max amount of air that can be exhaled after a max inhalation → also the max amount of air that can be moved into and out of lungs during a single respiratory cycle

what is inspiratory capacity IC?

the amount of air that can be inspired after a normal expiration

what is residual volume RV?

the air that remains in the lungs even after max expiration. this is because it helps lungs from collapsing