Respiratory System

Which lung is bigger? Why is it bigger?

Why does breathing in cold air hurt?

Can you get sick from breathing in cold
air?
Function
Gas
exchange for the body
–Supply O2
–Remove CO2
Structure
Two
major divisions:
–Upper Respiratory Tract
–Lower Respiratory Tract
Upper Respiratory Tract

Think holes
and tubes
Nasal/oral
cavities
 Pharynx
 Larynx
 Trachea

Upper Respiratory Tract
Air is
–Filtered
–Moistened
–Warmed
Lower Respiratory Tract

Think upside

Bronchi

Bronchiole

Alveoli
down tree
Bronchus vs. Bronchiole

Bronchus – lots of cartilage – won’t
collapse

Bronchiole – more muscle – so can dilate
and constrict
Alveoli
300 million alveoli in each lung
 Wall is single cell layer thick

Where does Respiration Occur?
Respiration:
Gas exchange
across a
membrane

Ventilation:
Conducting air
in/out


Which lung is bigger? Why is it bigger?

Why does breathing in cold air hurt?

Can you get sick from breathing in cold
air?
As Nate would say, “I don’t want to
breathe anymore…”
Ciliated
epithelial cells
in trachea (250
cilia/cell)
 Goblet cells
located between
these cells
produce ½ cup
of mucus/day

Coughing and Sneezing
the cilia beat about 1,000 1,500/minute,
moving mucus up about 10-20 mm/min
(1 mile/week)
 You cough when nerve endings in the
larynx, trachea, or larger bronchi are
irritated.
 You sneeze when nerve endings at the
back of the nasal cavity are irritated.


HOW do we breathe?

What keeps your lungs from collapsing?

How MUCH do we breathe?

How do we TRANSPORT what we breathe?

What makes us take the next breath?
HOW do we breathe?
What is the relationship between pressure
and volume?
HOW do we breathe? Inhaling:
1.
2.
3.
4.
Diaphram and intercostal muscles
contract – thoracic cavity expands
Lungs expand (adhered to walls)
Since intrapulmonary volume has
increased, pressure ____________.
Air is sucked in
http://www.smm.org/heart/lungs/breathing.htm
How do we breathe? Exhaling
1.
2.
3.
4.
Diaphram and intercostals relax
Thoracic/intrapulmonary volume
decreases
Intrapulmonary pressure is now ______
Gases flow out
So what keeps your lungs from
collapsing?

Intrapleural pressure is always negative

If it equalizes with atmospheric pressure (as in
a chest wound), lungs immediately collapse

Air in intrapleural space
= pneumothorax
How MUCH do we breathe?

Tidal volume – normal exhaled breath

Vital Capacity – largest exhaled breath

Residual Volume - left over amt after VC

Total Lung Capacity – RV + VC
How MUCH do we breathe?
How MUCH do we breathe?

Tidal volume – 500 ml

Vital Capacity – 4800 ml

Residual Volume - 1200 ml

Total Lung Capacity – 6000 ml
How do we TRANSPORT what we
breathe?
OXYGEN: Transported by hemoglobin (Hb) as
oxyhemoglobin (HbO2)

Each O2 attaches to
one Heme

Each RBC has 250
million hemoglobins
How do we TRANSPORT what we
breathe?
Carbon Dioxide: two methods
1.
On the globin of Hb
2.
As bicarbonate:
CO2 + H20
H2CO3
H+ + HCO3-
This occurs inside the RBC – but then the HCO3goes back into the blood plasma. WHY?
Carbonic anhydrase
Oxyhemoglobin
- HbO2
Carbaminohemoglobin
Bicarbonate
-
HCO3
- HbCO2
What makes us take the next
breath?
Too dangerous to wait for O2 levels to drop
 The major stimulus for inspiration is a slight
increase in blood acidity:

H+ + HCO3-
normoventilation
respiratory control
center in brain

What happens when you hypoventilate?

What happens when you hyperventilate?
What Is Asthma?

Spasmodic contraction of bronchi

Bronchial swelling

Increased production of mucus
What is bronchitis?

bronchi are inflamed and swollen

mucus is hypersecreted

Why?
What is emphysema?

Airways are permanently damaged

Alveoli are permanently damaged

Reduced ability to exchange gases
Diphtheria