trunks & special connective tissues line the lungs 

allows breathing while swimming

O₂ = ATP production

CO₂ = toxic in large concentrations

movement of molecules down a concentration gradient

necessary for gas exchange

rate determined by Fick's law

barometric = atmospheric

partial = pressure exerted by O₂ or CO₂

gases depend on partial pressure and solubility in water

better medium than water

O₂ content air > O₂ content water

O₂ diffuses 8,000 x faster in air

easier for animals to move in air

harder for aquatic animals to live

most water breathers are ectotherms

need more O₂ as temperatures rise

temperature increase = metabolism increase

O₂ content decreases with higher temp

O₂ decreases with altitude

pressure is much lower at high altitudes

O₂ is consistently 20.9% of air

CO₂ is more soluble in water

only .003% of air

diffuses easily

increase surface area

maximize partial pressure difference

minimize diffusion path length

minimize diffusion that occurs in water

highly branched and folded extensions of body surface to exchange in water

increase surface area

protected by body cavities

increase surface area

internal cavaties for respiratory exchange

highly divided and elastic

increase surface area

system of branching air-filled tubes in insects

insects don't have forced air systems

minimize path length - thin tissues

ventilation

perfusion

active movement of the external medium over the area of exchange

maximizes concentration gradient

in us: external medium = air

active movement of internal medium

maximizes concentration gradient

in us: internal medium = blood

counter current exchange

water flows one way

O₂ flows the opposite way

compress during inhalation 

expand during exhalation (opp. of us!)

unidirectional air flow

very little dead space

air sacs

need 2 breaths for blood to be useful

tidal ventilation

bidirectional flow

inspiratory reserve volume - full

expiratory reserve volume - force it out

vital capacity = tidal + reserve volumes

residual volume - dead space

nose/oral cavity

pharynx

larynx

trachea

bronchi

bronchioles

alveoli (exchange)

30 million alveoli make 70m² area 

(1/4 of basketball court)

very little tissue between alveoli and blood

mucus

surfactant

eliminates foreign particles and pathogens

mucus escalator = method of removal via cilia

reduces the surface tension of water

easier inflation of the lungs

like SOAP!

covers lungs in thoracic cavity

bound by diaphragm

diaphragm contracts

thoracic cavity expands

intrapleural pressure is more negative

lungs expand

air rushes in

the diaphragm expands

thoracic cavity contracts

intrapleural pressure is more positive

lungs contract

air rushes out

DIAPHRAGM IS RELE IMPORTANT

protein in red blood cells 

has a great affinity for O₂

depends on partial pressure of O₂ to deliver 

transports gases via blood

CO ties up hemoglobin ->

cannot transport O₂

CO poisoning - quick and easy way to die

hemoglobin composition

pH

2BPG, 3BPG

Bohr Effect

(pH)

acidic conditions reduce hemoglobin's affinity for O₂

***

biphosphoglyceric acid

metabolite of glycolysis

reduces hemoglobin's affinity for O₂

CO₂ Transport

blood has to transport waste, too!

forms carbonic acid with nearby water 

transported as bicarbonate ions 

facilitated via carbonic anhydrase

basically live in trees, need to pull more O₂

super hemoglobin = very high affinity for O₂

moms have more hemoglobin than avg

(breathing for 2)

1. Llamas

2. Mamas

3. You.

controlled in brainstem via autonomic NS

medulla adjusts it for eating, speaking, coughing, and emotion

affects breathing rate

higher CO₂ conc. = more we need to breathe

(convert CO₂ = oxygen)

OPPOSITE for aquatic animals

senses partial pressure of CO₂

H⁺ concentration >

 H⁺ binds to receptors

stimulus: H⁺ conc (acid) that exists in body because of CO₂

H⁺ are required for breathing

we breathe to get rid of acid

sense partial pressure of O₂

request increases in breathing rate