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