RespirationRespiration

Cellular RespirationCellular RespirationA reaction that occurs in the mitochondria

of the cell that requires O2 and that breaks down the end products of glycolysis into CO2 and water while capturing large amounts of energy as ATP.

Cellular RespirationCellular Respiration

What does diffusion mean?What does diffusion mean?

3 requirements that facilitate 3 requirements that facilitate diffusion in animal respiratory diffusion in animal respiratory

systemssystems

Respiratory surfaces must remain moistRespiratory surfaces must be very thinRespiratory system must have a large

surface area in contact with the environment

Not all animals Not all animals have lungs or gillshave lungs or gills

Some animals breath through their skinHave thin, gas permeable skin that provides

adequate surface area for the diffusion of gases

Usually live in moist habitatsUsually have low metabolic demands

Skin breathing animalsSkin breathing animals

Microscopic roundworm Flatworm

Sea jelly (jellyfish) Earthworm

Gas exchange (animals with Gas exchange (animals with well-developed resp. systems)well-developed resp. systems)1. Air or water is moved past a respiratory

surface by bulk flow2. O2 and CO2 are exchanged through the

respiratory surface by diffusion3. Gases are transported between the

respiratory system and the tissues4. Gases are exchanged between the tissues

and the circulatory system by diffusion

Gas ExchangeGas Exchange

GillsGills

Respiratory structures of aquatic animalsMay be extensions of the body surface into

the surrounding waterOr may be elaborately folded or branched

structures that increase surface area for gas exchange

GillsGills

Fish gills

Mexican axolotl

Shark

Mollusk

Terrestrial animalsTerrestrial animals

Transition from water to land - animals had to evolve respiratory structures that were:– Protected – Supported – Covered with a film of water

Tracheae – insectsLungs – terrestrial vertebrates

Tracheae - insectsTracheae - insects

Tracheae – elaborately branched internal tubes that convey air throughout the body

Are reinforced with chitin and found throughout the body tissues

Branch into microscopic tissues called tracheoles Which allow for gas exchange Spiracles – where air enters and leaves tracheae

(series of openings)

Insect tracheael systemInsect tracheael system

Terrestrial vertebrates use lungsTerrestrial vertebrates use lungs

Lungs – chambers containing moist respiratory surfaces that are protected within the body where water loss is minimized and the body wall provides support

Terrestrial vertebratesTerrestrial vertebrates

Tadpoles Bullfrog

Coral snake

Painted bunting

Wildebeest

Human respiratory systemHuman respiratory system

Can be divided into 2 parts:– Conducting portion– Gas-exchange portion

Conducting portionConducting portion

Brings air to the lungs Air enters: Nose or mouth Pharynx Larynx Trachea Branches into 2 bronchi Brochioles Alveoli

Larynx Larynx

Epiglottis – covers larynx and prevents food from entering

Contains Vocal Cords which are bands of elastic tissue controlled by muscles

Human respiratory passageHuman respiratory passage

Complications of the Complications of the respiratory passagesrespiratory passages

Smoking

Normal lung tissue Smokers lung

EmphysemaEmphysema

Complications Complications of the of the

respiratory respiratory passagespassages

Choking - Heimlich maneuver

Complications of the Complications of the respiratory passagesrespiratory passages

Asthma

Gas exchangeGas exchangeAlveoli – where gas exchange takes placeProvides large surface area for diffusionNetwork of capillaries cover most alveolar

surfaceRespiratory membrane

– Single layer of epithelial cells on alveoli (innermost portion)

– Single layer of endothelial cells that form the wall of each capillary

Respiratory membraneRespiratory membraneDiffusion of CO2 and O2 is a short distance

between air and blood – only 2 layers of cells thick

Alveoli Alveoli Surfactant lines alveoliThin layer of oily fluid that reduces surface

tension and prevents the alveoli from collapsing during exhalation

Gas exchangeGas exchangeDeoxygenated blood coming from heart

– Blood - High in CO2; Low in O2– Arrives at the alveoli in the lungs– CO2 travels down concentration gradient

through respiratory membrane into air Air in lungs – High in O2; Low in CO2

– O2 travels down concentration gradient through respiratory membrane into blood

– Oxygenated blood returns to heart to be pumped throughout body

In the tissues, O2 diffuses into cells because the concentration of O2 is lower in the cells than in the blood

Gas exchangeGas exchange

Transport of gases – CO2Transport of gases – CO2 CO2 transported in 3 different ways

– A little is dissolved in plasma– Some loosely bound to hemoglobin (iron-

containing protein in red blood cells)

– Most forms bicarbonate ion – HCO3-

Diffuses into plasma; helps maintain proper blood pH

This reverses when capillaries flow past the alveoli

CO2 wants to move down its concentration gradient into alveoli

Transport of gases – O2Transport of gases – O2

O2 carried by hemoglobin in red blood cellsHemoglobin can carry up to 4 O2 moleculesRemoves O2 from plasma, allowing O2 to

move down its concentration gradient from air to blood

Hemoglobin bound to O2 changes its shape and color

HemoglobinHemoglobin

Carbon monoxide (CO) poisoningCarbon monoxide (CO) poisoning

BreathingBreathingInvoluntary 2 stages1. Inhalation

– Contracts diaphragm muscle – enlarges chest cavity

– At rest, diaphragm domes upward– Rib muscles contract – lift ribs up and

outward– As chest expands - lungs inflate – draws

in air2. Exhalation

BreathingBreathing

Exhalation– Occurs automatically when muscles relax– Can also forcibly contract abdominal muscles

to exhale additional air

BreathingBreathing