Respiration Chapter 42. Respiration Gas exchange Movement of gas across membrane Diffusion...
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Transcript of Respiration Chapter 42. Respiration Gas exchange Movement of gas across membrane Diffusion...
Respiration
Chapter 42
Respiration
Gas exchange
Movement of gas across membrane
Diffusion (passive)
To improve gas absorption
Increase surface area for diffusion
Decrease distance diffused gas travels
Respiratory organs
Fish
Amphibians
Lungs
Cutaneous respiration
Amphibians
Birds
Parabronchi (lungs) Air sacs
Fig. 42-26
Anteriorair sacs
Posteriorair sacs Lungs
Air
Lungs
Air
1 mm
Trachea
Air tubes(parabronchi)in lung
EXHALATIONAir sacs empty; lungs fill
INHALATIONAir sacs fill
Anatomy
Mouth (nose)
Pharynx (back of throat)
Larynx (voice box)
Trachea
Anatomy
Anatomy
Anatomy
Bronchi (Bronchus)
Bronchioles
Alveoli
Air sacs
Gas exchange
One cell layer thick
Lung tissue consists of millions
Anatomy
Anatomy
Anatomy
Lungs
3 right lobes
RUL, RML, RLL
2 left lobes
LUL, LLL
Anatomy
Anatomy
Anatomy
Lung covered by a double folded membrane
Visceral pleural membrane:
Covers the lung
Parietal pleural membrane:
Lines inner wall of thoracic cavity
Anatomy
Pleural cavity:
Space between two membranes
Filled with fluid
Helps with movement of lungs
Breathing
Diaphragm
Muscle
Separates thoracic cavity from abdominal cavity
Intercostal muscles
Muscles between the ribs
Inhalation (inspiration)
Diaphragm contracts & flattens
Intercostal muscles contract
Raises the ribs
Increases volume (decreases pressure)
Air flows into the lungs
Exhalation (expiration)
Diaphragm relaxes & elevates
Intercostal muscles relax
Ribs lower
Decreased volume
Forces air out
Breathing
Breathing measurements
Tidal volume
Amount of air moved into & out of lungs at rest
Vital capacity
Maximum amount of air that can be expired after forceful exhalation
Breathing measurements
Control of breathing
Normal breathing Medulla oblongata Respiratory control center Neurons send impulse for muscles
(diaphragm/intercostal) to contract Inspiration (inhalation) Stop sending impulse Expiration (exhalation)
Control of breathing
Blood O2 & CO2 in normal range Neurons respond to a change in O2
& CO2
More response to CO2
Increase CO2 Increases carbonic acid (H2CO3) CO2 + H2O ⇆H2CO3 ⇆ H + HCO3
Lowers pH
Control of breathing
Stimulates peripheral chemoreceptors
Aorta & carotids
Send impulses to respiratory control center (medulla oblongata)
Stimulates increased breathing
Control of breathing
Central chemoreceptors
Located in brain
Respond to increased amount of CO2
Peripheral receptors immediate response
Central receptors maintained response until pH is back to normal
Transport of gas
Hemoglobin
Contains four heme groups
Center of each heme group is an iron
Oxygen binds the iron (4 O2 molecules)
Oxygen in blood is mostly bound to Hgb
Little is dissolved plasma
Transport of gas
Transport of gas
Oxyhemoglobin
Hemoglobin full of oxygen
Lungs
Deoxyhemoglobin
Hemoglobin releases some oxygen
Capillaries
Transport of gas
Blood that leaves lungs 97% saturated
Circulates oxygen diffuses into tissues
75% saturated
Allows for reserves of oxygen
Exercise
Cardiac arrest
Transport of gas
Decreased pH Lower affinity of oxygen for
hemoglobin Releases oxygen Increased temperature Lower affinity Exercise Increased CO2, decreased pH,
increased temperature Increased release of O2 to muscles
Transport of gas
CO2
In tissues
Small amount bound to protein part of Hgb
Remaining CO2 in RBC
Forms carbonic acid H2CO3
Carbonic anhydrase
Transport of gas
Carbonic acid separates
Bicarbonate (HCO3-1) & H+1
Buffer
Blood at alveoli
Carbonic anhydrase reverses
Forms water & CO2
CO2 diffuses into lungs
Abnormalities
Emphysema Lung disease that destroys alveoli sacs Decreases vital capacity Traps air Hypoventilation Decreased air movement increased CO2
Hyperventilation Increased air movement decreased CO2
Emphysema