Key concepts Types of respiration

Cellular Respiration is the chemical breakdown of food substances to yield ATP. Different organisms use different kinds of breathing mechanisms in order to transport oxygen

throughout their bodies. Evolutionary adaptations of gas exchange systems and respiration

Different plant adaptations in acquiring CO2 from the environment evolved: C3, C4, and CAM pathways.

Structural adaptations of respiratory apparatus depend on the animal’s habitat. The three most common respiratory organs are gills, tracheae, and lungs.

The respiratory system and circulatory system cooperate directly with each other. Mammalian respiration

The respiratory system is divided into the upper respiratory tract (nasal passages, mouth, throat, larynx and trachea) and lower respiratory tract (bronchi and the lungs).

Air enters (inhalation) the respiratory system due to a pressure drop inside the lungs (negative pressure).

Air exits (exhalation) the respiratory system due to an increase in pressure inside the lungs. Breathing is regulated by control centers in the brain (medulla oblongata and pons) Gases are transported via passive diffusion throughout the body.

Respiratory diseases and their prevention Respiratory disorders may be congenital or environmental. Respiratory disorders can be prevented through a combination of proper diet and lifestyle

change.

Vocabulary words aerobic respiration air sacs alveolus anaerobic respiration asthma blood pH Bohr shift breathing bronchiole bronchus C3 pathway C4 pathway CAM pathway cell respiration countercurrent exchange cutaneous respiration diaphragm dissociation curve

emphysema epiglottis gas exchange gills glottis glycolysis hemocyanin hemoglobin larynx (voicebox) lung Cancer lungs medulla oblongata myoglobin nasal cavity negative pressure breathing nose parabronchi partial pressure pharynx photosynthesis

pneumonia pons positive pressure breathing residual volume respiratory medium respiratory pigments respiratory surface rib muscles spiracle surface tension syrinx thoracic cavity tidal volume trachea or windpipe tracheae tuberculosis ventilation vital capacity vocal cords of the larynx

Cellular Respiration- Transformation of chemical energy into ATP- Overall Reaction: C6H12O6 +6O2 → 6CO2 +6H2O + 36 ATP

NADH and FADH2 are e- donors that enable the formation of ATP

Photosynthesis

Method of converting sun energy into chemical energy usable by cells

Light reactions Dark

reactions/Calvin Cycle

6 CO2 + 6 H2O + light energy → C6H12O6 + 6O2

Plant adaptations for acquiring CO2 from the environment

C3 (most abundant) CO2 converted to a 3C sugar, 3-

phosphoglycerate RuBisCO (Ribulose-1,5-bisphosphate

carboxylase/oxygenase) enzyme catalyzes carbon fixation

prone to photorespiration, lessens efficiency of food production during hot and dry days

C4 store CO2 in specialized compartments convert CO2 into a 4C compound, oxaloacetate converted into the 3C sugar and CO2 used in

the C3 pathway/Calvin cycle minimizes photorespiration and enhances sugar

production CAM

succulent plants f ix CO2 at night and store it as 4C organic acids minimizes water loss and enhances sugar

production

Gas exchange supplies oxygen for cellular respiration and removes CO2 Gas exchange –

uptake of O2 from environment and discharge of CO2

Mitochondria need O2 to produce more ATP, CO2 is the by-product

C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP Diffusion rate

α SA large α 1/d2 thin

Moist so gases are dissolved first

DIFFUSION

Respiratory surfaces and gas exchange Respiratory

surface Size of organism Habitat Metabolic demands

Unicellular organisms Entire surface area

for diffusion

Simple invertebrates Sponges,

cnidarians, flatworms

diffusion

Respiratory surfaces and gas exchange More complex

animals Thin, moist

epithelium Separates medium

from capillaries Entire outer skin

small, long, thin organisms

Specialized respiratory organs that are extensively folded and branched

Gills in aquatic animals

Outfoldings of the body surface suspended in water

Sea stars Segmented worms

or polychaetes Molluscs and

crustaceans Fishes Young amphibians Total surface area is

greater than the rest of the body

Water as a respiratory medium Surfaces are kept moist O2 concentrations in

water are low Ventilation – increasing

flow of respiratory medium over the surface

Countercurrent exchange – process in which two fluids flow in opposite directions, maximizing transfer rates

Why are gills impractical for land animals?

Just keep swimmin

g swimmin

g swimmin

g!

Air as a respiratory medium Air has a higher

concentration of O2 O2 and CO2 diffuse

much faster in the air less ventilation

Difficulty of keeping surface moist

Solution: respiratory infolding inside the body

Tracheal system of insects – network of tubes that bring O2 to every cell

Spiracles

Lungs Heavily vascularized

invaginations of the body surface restricted to one location

Found in spiders, terrestrial snails, vertebrates

Amphibians supplement lung breathing with skin

Turtles supplement lung breathing with moist surfaces in mouth and anus

Mammalian respiration

Lung ventilation through breathing

Positive pressure breathing in frogs

“Gulping in” air

Negative pressure breathing in reptiles and mammals

Rib muscles and diaphragm change lung volume and pressure

Lung volumes Factors

Sex Height Smoking Physical activity Altitude

Tidal volume Volume of air inhaled

and exhaled with each breath

Vital capacity Maximum volume

inhaled and exhaled during forced breathing

Residual volume Air left in alveoli after

forced exhalation

Avian breathing

Air sacs act as bellows to keep air flowing through the lungs.

Control centers in the brain regulate breathing

Gases diffuse down pressure gradients

concentration and pressure drives the movement of gases into and out of blood

Respiratory pigments O2 transport

Low solubility of O2 in H2O

Respiratory pigments are proteins with metal atoms Hemoglobin – Fe Hemocyanin – Cu Allow reversible binding

of O2 Drop in pH results in a

lowered affinity of hemoglobin for O2

Respiratory pigments

CO2 transport 7% in plasma 23% bound to

hemoglobin 70% as HCO3-

buffer

Fetal hemoglobinHbF has greater affinity to O2 than Hb

low O2% by time blood reaches placenta fetal Hb must be able to bind O2 with greater

attraction than maternal Hb

Deep-diving mammals

Seals, whales, dolphins are capable of long underwater dives

Weddell seal 5% O2 in lungs, 70% in blood

Huge spleen stores huge volumes of blood

Large concentrations of myoglobin in muscles

Heart rate and O2 consumption rate decrease

Blood is redirected from muscles to brain spinal cord and eyes