1. Macro Respiration
Chapter 42

2. What you need to know
The general characteristics of a respiratory surface.
The pathway a molecule of oxygen takes from the air until it is picked up by the hemoglobin of a red blood cell.

3. Respiration Uptake of O2 and discharge of CO2
Respiratory Medium is the source of O2
Air (21% O2)
Water (varies with temperature and salinity but always less than 21%)
As temp and salinity increase, O2 decreases
Gas diffuses based on gas pressure (partial pressure)
Always from high to low (simple diffusion)

4. Respiratory Surfaces
Always moist, single cell layer, epithelial tissue (skin cells)
Lungs, air sacs, trachea
In folding of body/skin *(favorable surface area to volume ratio)
Reduces water loss for terrestrials
Gills
Outer folding of body/skin *
Countercurrent exchange
Skin

5. Types of Respiration Skin Breathing (worms)
No specialized respiratory surface, high surface area to body volume required, they have to stay small, must live in moist environments

6. Types of Respiration Tracheal System (insects)
Extensive branching tubes reach every cell, no circulatory system required, low efficiency, organisms are small and ectothermic

7. Types of Respiration Gills (organisms)
Two or more, countercurrent exchange, high energy requirement

8. Types of Respiration Lungs (terrestrial vertebrates)
Large surface area through intense in-folding
Covered with moist epithelial tissue

9. Human Pulmonary System
Flow of air into the body:
Mouth or nose 
Pharynx (throat) 
Epiglottis (skin flap) 
Larynx (voice box) 
Trachea (windpipe) 
Bronchi (2 bronchus: 1 to each lung) 
Lungs which contain bronchioles (small tubules) and alveoli (tiny air sacs at the end of each bronchiole)

10. Functions of Organs Nasal cavity: cleans, moisturizes, and warms air
Larynx: sound
Epiglottis: separating food from air
Cartilage flap that covers the entrance to the trachea, only opens when you breath
Nervous system cross inhibition prevents swallowing and breathing at the same time

11. Functions of Organs
Trachea & bronchi: ciliated epithelial cells which secrete mucus to trap and remove any remaining dirt/dust/debris particles
Mucus is transported by cilia dispelling mucus out the throat and nose
Cystic fibrosis is a recessive mutation leading to thick mucus which is a breeding ground for bacteria

12. Functions of Organs
Lungs: spongy tissue with enormous surface area (football field)
Right lung has 3 lobes, left lung has 2
Surrounded by capillaries
Gases pass through 2 cell layers: alveoli cell and capillary wall cell

13. Gas Exchange Alveoli are tiny lung sacs 1 cell layer thick
Gases diffuse from high to low concentrations (higher O2 in alveoli, higher CO2 in the blood)

14. Gas Transport
Hemoglobin: quaternary protein, iron chelate in vertebrate erythrocytes (RBC)
Myoglobin: similar to hemoglobin, O2 storing protein in muscles
Hemolymph: protein/copper chelate in mollusks and arthropods
Most CO2 is bound in the blood liquid as carbonic acid (HCO3-)

15. Mechanics of Breathing
Diaphragm is a dome-shaped (relaxed) muscle separating the thorax from the abdomen
When the muscle contracts it flattens, pulling down the lungs, which creates a vaccuum = inhalation
Relaxation of the muscles = exhalation
Vital Capacity = maximum volume of air in lungs

16. Control Inovluntary Blood chemistry influences breathing rate
Medulla oblongata (brain stem) has O2 sensors

17. Respiratory Diseases
Infections: ears, nose, throat, bronchi (bronchitus), lungs (pneumonia)
Allergies: hayfever
Asthma: extreme allergic reaction leading to the constriction of bronchi
Emphysema: repeated infections and irritations leads to the replacement of alveoli with scar tissue
CF, smoking, pollution
Lung Cancer: mutated alveoli cells