Respiratory Physiology

Question 1

The trachea is lined with a ______

Answer 1

mucous membrane

Question 2

The bronchi is lined with

Answer 2

Smooth Muscle

Question 3

Ventilation: inhaling is described as ______ & exhaling is described as ________

Answer 3

Active, Passive

Question 4

The ventilatory muscle involved in breathing is _______

Answer 4

diaphragm

Question 5

_______ Dead Space – Air in tubes (150ml)

Answer 5

Anatomic

Question 6

__________ Dead Space – Near Apex
– Less O2/CO2 diffusion occurs here

Answer 6

Physiological

Question 7

___________ Muscles
– Quiet Breathing
* Diaphragm

Answer 7

Ventilatory

Question 8

–________ breathing
* Diaphragm
* Intercostals
* Scalenes

Answer 8

forced

Question 9

PCO2 is __________ respiratory stimulus

Answer 9

strongest

Question 10

PO2 is 105 mm/Hg in the _______

Answer 10

alveoli

Question 11

PO2 is only 40 mm/Hg in the _________

Answer 11

capillary

Question 12

Explain the physiology of a stitch.

Answer 12

Stitch
– Pain response interpreted by brain from low O2 in the respiratory muscles
* Un-trained individuals * Insufficient warm-up
* Too much in stomach * Talking while running
– This pain response will force you to reduce load on the respiratory muscles (ie. the pain slows you down)

Question 13

Explain why hyper-ventilating increases your breath-holding time.

Answer 13

Truth: We are exceptionally good at delivering oxygen to our cells. As humans we are so good that whether an athlete(aerobic or anaerobic), or even sedentary our O2 needs are well within capacity. We can deliver more O2 than our body would ever need to use.
Stimulus(why was I forced to breathe out?): by product production/waste products is what we use to regulate HR and respiration. HR + Respiration(linked)
Feedback loop: Chemoreceptors → talk to the medulla(specifically respiratory centres)[DRG & VRG]. DRG is a trigger that allows inspiratory breathing. VRG also deals with breathing rhythm –> DRG inhibits expiratory activity in VRG.

Variable/mechanism to control breath is PCO2(resting PCO2 35-45 mmHg)

We have a threshold associated with PCO2(50), before holding your breath PCO2 was fluctuating between 35-45. Holding breath means no more gas exchange occurs and PCO2 starts to rise. Once it reaches somewhere around 50 → forced to breathe out. Chemoreceptors alert that there is a significant rise and that’s no good:( need to balance out.
Hyperventilation drops PCO2 by about 15-20 mmHg → PCO2 levels have to rise past resting values and reach “blow off point”, then able to hold breath for longer.

Question 14

Which is preferred during exercise, fewer larger breathes, or more frequent shallower breathes? Explain.

Answer 14

Fewer deeper breaths
- 20 deep breaths 500ml
150ml lost in dead space
so amount inhale = 500 - 150 = 350 x 20 breaths = 7000

VS
- 40 short breaths at 250 mL = 250 - 150 = 50 x 40 breaths = 2000

Question 15

Explain why you may be breathing heavily after a bout of anaerobic exercise.

Answer 15

More PCO2 build up needed to be taken care of.

Question 16

Explain why and how VE increases during exercise.

Answer 16

VE is minute ventilation and it is the air breathed per minute. VE increases through exercise by:
- body having to adjust and regulate to body’s movements(homeostasis)
- More O2 being used
- More CO2 removed(metabolic demands)

Question 17

Explain how oxygen (or vice versa for CO2) in the air around us arrives at the mitochondria (site of Kreb’s Cycle and Electron Transport Chain) in our muscles. (be sure to include: the path O2 or CO2 takes in respiratory tract, a definition of diffusion, diffusion at the lungs, how O2 or CO2 is transported in the blood, diffusion at the muscle).

Answer 17

1. Path in the Respiratory Tract:
   Oxygen enters the body through the nose or mouth and travels down the respiratory tract.
   It passes through the pharynx, larynx, trachea, and then enters the bronchial tree.
   In the bronchial tree, oxygen moves through smaller and smaller air passages, eventually reaching the alveoli in the lungs.
2. Diffusion:
   Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration until equilibrium is reached.
   In the lungs, oxygen diffuses from the alveoli (where it is highly concentrated) into the surrounding capillaries (where it is lower in concentration) due to the pressure difference.
3. Diffusion at the Lungs:
   Oxygen diffuses across the thin walls of the alveoli and into the adjacent capillaries, where it binds to hemoglobin molecules in red blood cells.
   Hemoglobin acts as a carrier, allowing oxygen to be transported efficiently through the bloodstream.
4. Transport in the Blood:
   Oxygen is primarily transported in the blood bound to hemoglobin, forming oxyhemoglobin.
   Some oxygen is also transported dissolved in the plasma, but the majority is carried by hemoglobin.
   The oxygenated blood is then pumped by the heart from the lungs to the rest of the body, including the muscles.
5. Diffusion at the Muscles:
   As oxygen-rich blood flows through the capillaries surrounding the muscle cells, oxygen diffuses out of the blood and into the muscle cells.
   Inside the muscle cells, oxygen is used in the mitochondria to support aerobic metabolism, including the Krebs cycle and the electron transport chain.
   Carbon dioxide, a byproduct of cellular respiration, diffuses out of the muscle cells into the bloodstream and is transported back to the lungs for exhalation.

In summary, oxygen in the air around us travels through the respiratory tract, diffuses into the bloodstream at the lungs, is transported by hemoglobin in red blood cells, and then diffuses into muscle cells where it is used in cellular respiration. Conversely, carbon dioxide is produced as a byproduct of cellular respiration, diffuses into the bloodstream, is transported back to the lungs, and then diffuses out of the body during exhalation.