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Ch 49 - Gas Exchange
BIOL197 @ UNLV; exam 3
45
Biology
Undergraduate 3
08/06/2011

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Cards

Term
Elephants
Definition

trunks & special connective tissues line the lungs 

allows breathing while swimming

Term
O2 and CO2
Definition

O2 = ATP production

CO2 = toxic in large concentrations

Term
Diffusion
Definition

movement of molecules down a concentration gradient

necessary for gas exchange

rate determined by Fick's law

Term
Partial Pressure in Air
Definition

barometric = atmospheric

partial = pressure exerted by O2 or CO2

gases depend on partial pressure and solubility in water

Term
Air
Definition

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

Term
Temperature
Definition

most water breathers are ectotherms

need more O2 as temperatures rise

temperature increase = metabolism increase

O2 content decreases with higher temp

Term
Altitude
Definition

O2 decreases with altitude

pressure is much lower at high altitudes

O2 is consistently 20.9% of air

Term
CO2 Diffusion
Definition

CO2 is more soluble in water

only .003% of air

diffuses easily

Term
Adaptations
Definition

increase surface area

maximize partial pressure difference

minimize diffusion path length

minimize diffusion that occurs in water

Term
External Gills
Definition

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

increase surface area

Term
Internal Gills
Definition

protected by body cavities

increase surface area

Term
Lungs
Definition

internal cavaties for respiratory exchange

highly divided and elastic

increase surface area

Term
Tracheae
Definition

system of branching air-filled tubes in insects

insects don't have forced air systems

Term
Maximizing Partial Pressure Difference
Definition

minimize path length - thin tissues

ventilation

perfusion

Term
Ventilation
Definition

active movement of the external medium over the area of exchange

maximizes concentration gradient

in us: external medium = air

Term
Perfusion
Definition

active movement of internal medium

maximizes concentration gradient

in us: internal medium = blood

Term
Fish Gills
Definition

counter current exchange

water flows one way

O2 flows the opposite way

Term
Bird Lungs
Definition

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

Term
Dead Space
Definition
air left in lungs after exhalation
Term
Air Sacs
Definition
receive inhaled air but don't exchange it
Term
Mammalian Lungs
Definition

tidal ventilation

bidirectional flow

inspiratory reserve volume - full

expiratory reserve volume - force it out

vital capacity = tidal + reserve volumes

residual volume - dead space

Term
Human Lungs - Airway
Definition

nose/oral cavity

pharynx

larynx

trachea

bronchi

bronchioles

alveoli (exchange)

Term
Alveoli
Definition

30 million alveoli make 70m2 area 

(1/4 of basketball court)

very little tissue between alveoli and blood

mucus

surfactant

Term
Mucus
Definition

eliminates foreign particles and pathogens

mucus escalator = method of removal via cilia

Term
Surfactant
Definition

reduces the surface tension of water

easier inflation of the lungs

like SOAP!

Term
Pleural Membrane
Definition

covers lungs in thoracic cavity

bound by diaphragm

Term
Inhalation
Definition

diaphragm contracts

thoracic cavity expands

intrapleural pressure is more negative

lungs expand

air rushes in

Term
Exhalation
Definition

the diaphragm expands

thoracic cavity contracts

intrapleural pressure is more positive

lungs contract

air rushes out

DIAPHRAGM IS RELE IMPORTANT

Term
Intercostal and Abdominal Muscles
Definition
contribute to expansion of thoracic cavity and expiratory reserve volume
Term
Hemoglobin
Definition

protein in red blood cells 

has a great affinity for O2

depends on partial pressure of O2 to deliver 

transports gases via blood

 

Term
CO2 and Hemoglobin
Definition

CO ties up hemoglobin ->

cannot transport O2

CO poisoning - quick and easy way to die

Term
Myoglobin O2
Definition
reserves in muscles to account for interruptions of blood flow
Term
O2 Binding Factors
Definition

hemoglobin composition

pH

2BPG, 3BPG

Term
Hemoglobin Composition
Definition
slight differences in structure change O2 affinity
Term

Bohr Effect

(pH)

Definition

acidic conditions reduce hemoglobin's affinity for O2

***

Term
2,3 BPG
Definition

biphosphoglyceric acid

metabolite of glycolysis

reduces hemoglobin's affinity for O2

Term

CO2 Transport

 

Definition

blood has to transport waste, too!

forms carbonic acid with nearby water 

transported as bicarbonate ions 

facilitated via carbonic anhydrase

Term
Llamas
Definition

basically live in trees, need to pull more O2

super hemoglobin = very high affinity for O2

 

Term
Maternal / Fetal Hemoglobin
Definition

moms have more hemoglobin than avg

(breathing for 2)

Term
Battle of O2 Transport
Definition

1. Llamas

2. Mamas

3. You.

Term
Breathing Regulation - Brain Stem
Definition

controlled in brainstem via autonomic NS

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

 

Term
Regulation - CO2
Definition

affects breathing rate

higher CO2 conc. = more we need to breathe

(convert CO2 = oxygen)

OPPOSITE for aquatic animals

 

Term
Ventral Surface of Medulla
Definition

senses partial pressure of CO2

H+ concentration >

 H+ binds to receptors

Term
Neural Firing!!!
Definition

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

H+ are required for breathing

we breathe to get rid of acid

 

Term
Aorta and Carotid Arteries
Definition

sense partial pressure of O2

request increases in breathing rate

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