Respiratory System Flashcards
What is internal respiration
Exchange of gas in the lungs and body tissues.
diffusion of oxygen from lung into the blood
and CO2 from blood to lungs
diffusion of oxygen from blood into into the cells
and CO2 from cells to blood
what is External respiration
process of inhaling air and transporting oxygen from nose or mouth to the lungs till oxygen is defused in the blood stream. And vice versa, where we expel CO2
this function is controlled by the prephiral system - the autonomic nervous system - because it’s done unconsciously
however we constant control the depth and rate of our breathing
Explain inhilation process
1.Air enters mouth or nose
2.Air passes through pharynx (tube between nose and larynx) and then to larynx (voice box)
3.Air passes to Trachea (semi-regid tube built with cartilage rings).
4.Trachea branches into 2 bronchi servicing each lung
5.Particles in the air get caught here the mucus lined walls of bronchi and trachea then slowly back up the mouth
6.Bronchi split into 2 again and again
7.As air passes through, it gets moist and warm
8.Bronchi eventually end at the Avleoli. Its walls are coated with fine layer of moisture
9.Alveoli are small spherical bags grouped in Alveoli sacs.
10.Membrane of the alveoli are thin and surrounded by capillaries
11.The pressure of oxygen in the air helps with the oxygen diffusion into the blood
12.The oxygen molecules entering each alveolus dissolve into liquid and through its members and into the capillaries, into the blood plasma
13.O2 molecules bind to the haemoglobin in the red blood cells
14.oxygenated blood passes to the left side of the heart, which then pumps it out into the body via arteries.
Explain Expiration
1.Simultaneously, deoxygenated blood travels to the right side of the heart
2.Pumps it back into the alveoli
3.In the Alveoli sac, CO2 molecules in the blood diffuse across the membrane into the alveoli from where they are expelled from the body via breathing out. Some of this process also happens at the final stages of bronchi
How much oxygen does the brain take
(even though our brain makes up 2% of our body weight) our brain consumes 20% of the oxygen we take in
how many alveolis are in normal human
300,000 alveolis exist in the body - this makes up 80m2 of gas exchange area
during hard excercise, how fast does blood pass from alveoli to capillaries
To keep the body oxyginated during excercise, it take 0.3 seconds for blood to pass from alveoli to capillaries
how many inhilations/exhilations are made per min and what does this equate in heart beats per min
15 inhilations & exhilations per min
= 70 heart beats/min
Relationship between Oxygen and Carbon Dioxide
- Body stores more CO2 than O2 hence why the body needs sufficient levels of O2
- CO2 helps body regulate O2
- CO2 helps maintain chemical balance in the body
- Breathing rate is affected by CO2 but also stress, anxiety, illness or injury
- O2 saturation levels in the blood is usually held at 98%. It drops below 90% when the Partial Pressure drops to 60mmHG
- Might seem when take in a lot of oxygen when we exercise but oxygen levels in the blood are held at tight limits
External mechanism to assist the lungs in external respiration
Brochi don’t have the ability to support themselves, therefore the lungs cannot inflat themselves. Infact, lungs can collapse if pressure in lungs is lower than that of the chest cavity
therefore, external mechanism is required that relies on:
Pleural cavity
Thorax
Diaphragm
InterCostal muscle
What is pleural cavity
The lungs are protected by the pleural membrane
The space between the lungs and the pleural memberane is the pleural cavity
What is thorax
Lungs and heart are located in the Thorax (chest cavity)
The thorax also has airtight membrane
the thorax is seprated from lower abdominal cavity by the diaphragm
What is the diaphragm
a muscle that separates thorax from abdominal cavity.
it flattens when breathing in, and relaxes into cone shape when breathing out.
Explain what happens when breathing in
Breathing in causes the diaphragm to flatten because the volume of ai in the lungs expands.
Here the pressure in the pleural cavity is lower
compared to the pressure in the lungs
What happens when breathing out
Breathing out causes the diaphragm to relax and go back to its cone shape.
the volume of air in the lungs reduces.
Here the pressure in the pleural cavity is higher
compared to the pressure in the lungs
the compressed lungs expel CO2
What is the muscle that helps the Diaphragm
During intense excercise, the body needs a lot of oxygen and to the support the speed of inhalation and exhilation, the diaphragm needs the
InterCostal Muscle - sits in the ribs and helps expand the ribs to allow the lungs to expand ( more volume) and vice versa
What is volutary respiration
When you can consciously control your breathing (holding breath, signing, etc)
Involunatry repiration
Occurs in the inenr body (with the brain) and to some degree is automatic
How does Carotid arteries assis in involutary respiration
in the coratid artery, there are sensors that monitor the acidity of the blood and the levels of CO2 and O2.
If CO2 are high, these sensors send signals to the brain and the brain sends signals to the Thorax to expand and ‘inhale’ more air
Hyperventiation definition
when body is needing to **breath fast and deeply **more oxygen more than the usual
feeling breathlesness even though you are breathing more oxygen
What is happening physiologically during hyperventilation
Overbreathing causes excessive flushing out of CO2 from the body.
The carotid artery recognizes that the carbonic acid is reduced and thus sends signals to the nervous system, and this signal constricts the blood vessels …..hence reduced blood flow to the brain
What causes hyperventilation
Anxiety & stress
Movements such as: turbulence, vibration, g force, motion sickness
Stroke & brain injury
Voluntary hyperventilation
