Body Systems - Respiratory System

Non-AP Bio 20 content

Anaerobic Respiration

Respiration that doesn’t use oxygen. Occurs in all organisms (glycolysis). Produces very little ATP

Aerobic Respiration

Respiration that uses oxygen. Occurs in the mitochondria and produces many ATP (34-36)

Respiratory System

System through which gases are exchanged, oxygen in CO2 out.

1. Mouth/Nasal Passage

2. Pharynx

3. Larynx

4. Trachea

5. Bronchus

6. Bronchioles

7. Lungs

8. Alveoli

Gas Exchange

Movement of oxygen and CO2 between environment, capillaries, and cells. Require moist membranes, high surface area, and thin tissue for optimized exchange. Occurs in the alveoli

Gas Exchange - Surface Area

Maximize gas exchange rate. More CO2 and oxygen move across cell membrane by diffusion

Gas Exchange - Moist Membranes

Gases have to diffuse in water to get dissolved in the blood. Can’t have lungs sticking together

Gas Exchange - Thin Membrane

Easier for gases/fluids to travel across

Counter-Current Exchange System

Oxygen-rich water moves through gills of a fish, losing concentration as it goes further in. Blood is circulated so that the most oxygen-rich blood is where the most oxygen-rich water is (allows for continuous diffusion of water into system).

Gas Exchange on Land - Advantages

• Increased concentration of oxygen

• Oxygen and CO2 diffuse faster through air

• Respiratory surfaces exposed to air don’t have to be as thoroughly ventilated (lungs vs gills)

• Air is lighter than water, easier to pump → decreased energy expended moving air in and out

Gas Exchange on Land - Disadvantages

• Need to keep large respiratory surface moist, increased water loss

  • Counteracted by having internal lungs

Positive Pressure

Air is forced down into the lungs, pushed out because of elasticity of lung tissue. Occurs in amphibians

Negative Pressure

Air is sucked into lungs by creating area of lower pressure than surrounding environment by lowering the diaphragm. Intercostal muscles contract to raise ribs and sternum. Air forced out when muscles/diaphragm relax. Occurs in humans

Mechanics of Breathing

1. Medulla oblongata determines rhythm of breath

2. Air enters nostrils (warmed, filtered, humidified)

3. Passes through pharynx, larynx, trachea, bronchi, bronchioles to alveoli

Air filtering

• Nostrils - nose hairs catch small particles

• Epithelial lining covered by cilia with mucus - traps particles like dust and pollen, beating cilia moves mucus upwards to pharynx to be swallowed

Homeostasis

Keeping internal environment of body balanced, different than equilibrium. Balances O2 in, CO2 out and ATP production

Effect of exercise on breathing

Need to breathe faster: produce more ATP, remove more CO2, bring in more O2. CO2 produced when exercising, raises pH and signals increased need to cycle gases

Effect of disease on breathing

Poor lung and heart function result in needing to breathe faster. Need to work harder to bring in O2 and remove CO2

Surfactants

Substance to reduce surface tension/disrupt hydrogen bonds of water in alveoli. Prevents alveoli from clumping together and collapsing. Amount increases in babies as birth weight increases

Hemoglobin

Oxygen carrier molecule because oxygen isn’t soluble enough in water for animal needs. Reversibly binds to O2 (can pick up from blood and drop off at cells). Progressively more attracted to O2 as picks up O2 (first binding of oxygen changes shape to bind easier to other oxygen, works in reverse with releasing). Has iron to allow bonding to oxygen, red colour

Hemocyanin

Hemoglobin equivalent in insects. Copper based, blue/green colour

Effect of pH

Decrease in pH (increased CO2) cause more O2 to be released from hemoglobin (increased cellular respiration increases carbonic acid to lower pH). Causes a Bohr shift

Bohr Shift

Drop in pH increases hemoglobin’s affinity for O2. Increases in temperature lowers hemoglobin’s affinity for O2. Lets more oxygen get released at muscles that are being used

CO2 Transport

Mostly diffused in red blood cells. Dissociates into bicarbonate ions where it then binds with a proton to make HCO3-. Buffers pH, diffuses into plasma as bicarbonate ion

Hemoglobin bound to oxygen

Oxyhemoglobin

Hemoglobin bound to CO2

Carbaminohemoglobin

Hemoglobin Binding

Binding of proton releases oxygen in tissues with low pH. Binding of oxygen releases proton (proton then combines with HCO3- to make H2CO3)

CO2 to the lungs

Hemoglobin releases proton and HCO3- combines with proton to make H2CO3. H2CO3 converted back into CO2 and H20, CO2 diffuses into interstitial fluid → alveoli to be diffused out.

CO2 from blood to lungs

Lower CO2 pressure in lungs allows CO2 to diffuse out of the blood into the lungs

Adaptations for Pregnancy

Mother and fetus exchnage oxygen and CO2 across placental tissue.

Fetal hemoglobin (hemoglobin with greater attraction to O2 - decreased O2% by the time blood reaches placenta) used to allow fetus to breathe

Regulations of Breathing

Regulated by CO2 concentration not O2, negative feedback loop

1. Medulla oblongata monitors CO2 levels, when pH decreases sends signal to increase breathing rate at diaphragm and intercostal muscles

2. Expels excess CO2

3. Carotid Artery: Artery to monitor CO2 and O2 levels

4. When O2 drops or CO2 increases, message to medulla to increase breathing

Chemoreceptors

Chemical receptors. CO2 receptors more sensitive, trigger breathing first. O2 receptors only kick in when CO2 levels stay the same (eg in high altitude)

Lung Volume Vocaulary

1. Tidal Volume

2. Vital Lung Capacity

3. Inspiratory Reserve Volume

4. Expiratory Reserve Volume

5. Residual Volume

6. Total Lung Capacity

Tidal Volume

Regular breathing volume

Vital Capacity

Maximum intake and expiration of air

Inspiratory Reserve Volume

Breathing in normally and then whatever else you can breathe in

Expiratory Reserve Volume

Breathing out normally and then whatever else can be forced out

Residual Volume

Air left in lungs after maximum exhale (because lungs don’t become flat)

Total Lung Capacity

Total air that can be held in the lungs

Bronchitis

Narrowing of bronchiole tubes (bronchus or bronchioles). Causes mucus, swelling, narrowing of airways, and decreased air flow. Bronchioles may collapse because not supported by cartilage rings

Emphysema

Inflammation of the alveoli. Alveoli lose elasticity and may burst, affects gas exchange

Pneumonia

Fluid buildup in the lungs

Asthma

Inflammation of bronchioles. Hard to force air out