Unit 5&6 Flashcards
Conducting Zone
(no gas exchange) :
Send air to respiratory zone
Conducting Zone’s Structure
- Nasal & oral cavities
- Pharynx & larynx
- Trachea
- Bronchi
- Terminal bronchioles
Respiratory Zone
(gas exchange):
Receive air from conducting zone
Respiratory Zone’s Structure
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sacs
- Alveoli
Def. of Ventilation
move air in & out of lungs
Def. of Transportation
oxygen & carbon dioxide between lungs & tissues
Def. of External respiration
gas exchange between lungs & blood
Def. of Internal respiration
gas exchange between blood & all body cells
Def. of Nasal Cavity
- Provides an airway for respiration
- Moisten, warm or cool, filter air
- Resonating chamber (speech)
- Olfactory receptors
What does Mucous contain and what it destroys?
lysozyme, bacteria
Function of Larynx
- Airway to the lungs
- Voice production
True vocal cords:
- Inferior to false vocal cords
- Vibrate (elastic) to produce sound as air rushes up from lungs
False vocal cords:
- Superior to true vocal cords
- No sound production
Sound is “shaped” into language by:
- Pharynx
- Tongue
- Soft palate
- Lips
Type I alveolar cells
Gas exchange
Type II alveolar cells
Secrete surfactant
Function of Alveolar pores
- Connect alveoli
- Equalize air pressure throughout lung
- Macrophages (dust cells) keep alveoli sterile
Sequence of Pulmonary Circulation
RV → Pulmonary trunk → pulmonary arteries → pulmonary capillaries (surrounding alveoli) → pulmonary veins → LA
Function of Parietal pleura:
Covers pleural cavity wall
Function of Visceral pleura:
Covers external lung surface
Inspiration (inhalation)
air enters lungs
Expiration (exhalation)
air exits lungs
Pulmonary Ventilation
- Depends on thoracic cavity volume changes
- Volume changes → pressure changes
- Pressure changes → gas flow
- Gases move along a pressure gradient (↑pressure → ↓pressure)
Boyle’s Law
-Describes an inverse relationship between pressure & volume of gases:
↑V → ↓P ↓V → ↑P
-P = gas pressure (mmHg)
-V = gas volume (mm3)
Inspiration according to Boyle’s Law
- ↑Thoracic cavity volume causes ↓pressure inside the lungs
- Air moves from atmosphere → lungs
Expiration according to Boyle’s Law
- ↓Thoracic cavity volume causes ↑pressure inside the lungs
- Air moves from lungs → atmosphere
Atmospheric pressure (Patm):
pressure exerted by air surrounding the body
Intrapulmonary pressure (Ppul):
pressure w/in alveoli
Intrapleural pressure (Pip):
- pressure w/in pleural cavity
- Intrapleural pressure is always <atmospheric pressure
Transpulmonary Pressure
- Transpulmonary pressure = intrapulmonary pressure – intrapleural pressure
- Keeps lung tissue expanded
- Prevents lung collapse
Def. of Friction:
major source of resistance to airflow
Relationship between flow (F) & resistance (R):
↑R → ↓F
↓R → ↑F
What is the normal transpulmonary pressure?
760 mmHg
What does severely constricted or obstructed bronchioles do?
Prevent normal ventilation
What does epinephrine do?
dilates bronchioles (↓resistance)
What does Ach (aceteylcholine) do?
Increase resistance, constrict bronchioles
Def. of surface tension
attraction of water molecules for one another
What does water in the alveolar surface coating do?
to ↓alveolar size (collapse)
Surfactant (phospholipid):
- Soap-like
- ↓Surface tension
- Prevents alveoli from collapsing
3 ways Thoracic Volume Increases During Inspiration
- Expansion → superior & inferior direction (top to bottom)
- Expansion → anterior & posterior direction (front to back)
- Expansion → lateral direction (sideways)
Muscles used during Inspiration
Diaphragm & external intercostal muscles contract
Inspiration
- Rib cage rises & expands
- Lung volume increases
- Intrapulmonary pressure decreases below atmospheric pressure
- Air flows into lungs (↑P → ↓P)
3 ways Thoracic Volume Decreases During Expiration
- Compression → superior & inferior direction (top to bottom)
- Compression → anterior & posterior direction (front to back)
- Compression → lateral direction (sideways)
Muscles used for NORMAL expiration
ALL muscles RELAX
Expiration
- Rib cage lowers
- Lung volume decreases
- Intrapulmonary pressure rises above atmospheric pressure
- Air flows out of lungs (↑P → ↓P)
Muscles used during FORCED inspiration
diaphragm, external intercostals, sternocleidomastoids scalenes, pectoralis minors contract
Muscles used during FORCED expiration
internal intercostals, abdominal muscles contract
Tidal Volume (TV)
air moving into & out of the lungs w/ each breath (500 mL)
Expiratory Reserve Volume (ERV):
air evacuated from the lungs below tidal volume (1200 mL)
Residual Volume (RV):
air remaining in lungs after forced expiration (1200 mL)
Vital Capacity (VC):
amount of exchangeable air during normal breathing (4800 mL)
VC = TV + IRV + ERV
Total Lung Capacity (TLC):
maximum amount of air that can be held in the lungs (6000 mL)
TLC = VC + RV
Respiratory Rate (RR):
total breaths per minute (BPM)
Respiratory Minute Volume (RMV):
normal air volume exchanged per minute (mL/ min)
RMV = RR x TV
Forced Vital Capacity (FVC)
air forcibly expelled after taking a deep breath
Forced Expiratory Volume (FEV)
air expelled during time interval (1.0 sec.)
Respirometer:
instrument that evaluates & measures respiratory function (spirogram)
What does Spirometry evaluates:
- Obstructive disorders
- Restrictive disorders
Name Obstructive disorders and its abnormal or normal value
- asthma, bronchitis emphysema
- Abnormal FEV
- Normal VC
Name Restrictive disorders and its abnormal or normal value
- pulmonary fibrosis, black lung, white lung, all others
- Normal FEV
- Abnormal VC
Eupnea
Normal respiratory rate & rhythm
What is the normal respiratory rate?
12-18 breaths per minute
Apnea
- Cessation of breathing
- Sleep apnea: cease to breathe for short periods during sleep
Dyspnea
- Difficult or labored breathing
- Often occurs in people who smoke
Hyperventilation
Above normal rate & depth of breathing
Hypoventilation
Below normal rate & depth of breathing
Shortness of Breath
Reduced ability to inhale completely
Anoxia
Severe oxygen deficiency
Pneumothorax
-Presence of atmospheric air between parietal pleural & visceral pleural membranes (pleural space)
-Causes:
Chest wall perforation
-Pneumothorax may lead to atelectasis
Atelectasis
- Collapsed lung
- Causes:
- Chest wounds (gunshot, stabbing, broken rib)
- Tearing of pleural membranes (auto accident, severe fall)
Chronic Obstructive Pulmonary Disease (COPD)
Chronic bronchitis & emphysema
Patient history of COPD
Smoking, dyspnea, coughing & frequent infections
What does COPD victims develop:
- Respiratory failure
- Hypoxia
- Carbon dioxide retention
- Respiratory acidosis
Asthma
- Characterized by: dyspnea, wheezing, chest tightness
- Airway inflammation
- Immune response to dust mites, cockroaches, dander, pollen, mold spores, rubber particles
- Stimulates IgE (recruits inflammation)
- Airways thickened w/ mucus (obstruction)
- Sense of panic
Tuberculosis
I-nfectious disease
- Cause: airborne bacterium -Mycobacterium tuberculosis
- Resistant strains are increasing
- Symptoms: fever, night sweats, weight loss, coughing, severe headache, blood in sputum, destruction of lungs & other body organs (“consumption”)
- Treatment: 12-month course of antibiotics
Bronchiogenic Carcinoma
- ⅓ of cancer deaths (U.S.)
- 90% of lung cancer patients were smokers
Emphysema
- Destruction of alveolar walls
- Chronic inflammation
- Loss of lung elasticity
- Collapse of bronchioles during expiration
- Typically caused by: smoking
Bronchitis
- ↑Mucus production
- Inflammation
- Frequent infections
- Causes: inhaled irritants (smoke, chemical fumes, dust, microbes)
Pneumonia
- Inflammation of lung passages & spaces
- Fluid accumulation w/in alveoli
- ↓Gas exchange (hypoxia)
- Potential for severe illness, death
- Mainly caused by viruses & bacteria
Cystic Fibrosis (CF)
- Overproduction of mucus
- Blocks: respiratory passageways, pancreatic duct, common bile duct
- Recessive genetic disease
- Caused by a faulty gene that codes for thickened mucus
Nitrogen (N2)
78.60% (.7860)
Oxygen (O2)
20.90% (.2090)
Carbon Dioxide(CO2)
.04% (.0004)
Water (H2O)
.46% (.0046)
Dalton’s Law of Partial Pressure
- Partial pressure = pressure exerted by a single gas in a system (atmosphere, blood, tissues, lungs)
- Sum of the individual partial pressures = total pressure in a system
- Total pressure = barometric pressure (760 mmHg at sea level)
Calculation of Partial Pressure
- Partial pressure is directly proportional to % of a gas in a mixture
- Partial Pressure (P) = % of gas x total pressure
Percentage of nitrogen in the atmosphere is 78.60%
Total barometric pressure of the atmosphere is 760 mmHg
What is PN2 partial pressure?
.786 x 760 mmHG = 597.36 mmHg
Percentage of oxygen in the atmosphere is 20.90%
Total barometric pressure of the atmosphere is 760 mmHg
What is PO2 partial pressure?
0.209 x 760 mmHg= 158.84 mmHg
Percentage of carbon dioxide in the atmosphere is 0.04%
Total barometric pressure of the atmosphere is 760 mmHg
What is PCO2 partial pressure?
0.0004 x 760 mmHg= 0.304 mmHg
Percentage of water in the atmosphere is 0.46%
Total barometric pressure of the atmosphere is 760 mmHg
What is PH2O partial pressure?
0.0046 x 760 mmHg= 3.496 mmHg
Pulmonary Ventilation
- Air exchange between atmosphere & lungs (breathing)
- Depends on chest & diaphragm movements, clear airways
Def of Inhalation (inspiration)
- ↓pressure inside lungs (air moves in)
Def of Exhalation (expiration)
- ↑pressure inside lungs (air moves out)
External Respiration
-Gas exchange between lung alveoli & pulmonary circulation blood
-Depends upon:
*Gas partial pressure differences
*Lung membrane health
* Blood flow into & out of lungs
ALVEOLUS ↔ BLOOD
Internal Respiration
-Gas exchange between blood & body cells
-Depends upon:
* Gas partial pressure differences
BLOOD ↔ CELLS
Respiration Summary Equation
ALVEOLUS ↔ BLOOD ↔ CELLS
Law of Diffusion:
- gases move from a region of high partial pressure (↑) to a region of low partial pressure (↓)
- If lungs have a higher gas pressure than blood, gas moves into blood along a partial pressure gradient (↑ to ↓)
O2 Partial Pressure Gradients of Venous blood oxygen (PO2)
40 mmHg
O2 Partial Pressure Gradients of Alveolar blood oxygen (PO2)
104 mmHg
O2 Partial Pressure Gradients
- Steep gradient
- Oxygen partial pressures rapidly reach equilibrium
- Blood moves quickly through a pulmonary capillary but will still normally add O2
CO2 Partial Pressure Gradients of Venous blood carbon dioxide (PCO2)
46 mmHg
CO2 Partial Pressure Gradients of Alveolar blood carbon dioxide (PCO2)
40 mmHg
CO2 Partial Pressure Gradients
- Non-steep gradient
- Carbon dioxide partial pressures rapidly reach equilibrium
- Blood moves quickly through a pulmonary capillary but will still normally remove CO2
Gas Solubilities
- Carbon dioxide has a non-steep partial pressure gradient compared to oxygen
- Henry’s Law
- Carbon dioxide is 20x more soluble in plasma than oxygen
- Result: Carbon dioxide diffuses in equal amounts w/ oxygen
Carbon Dioxide (CO2) Transport Dissolved in Plasma %
10%
Carbon Dioxide (CO2) Transport Chemically Bound to Hemoglobin in the RBC
20%
Carbon Dioxide (CO2) Transport As a Bicarbonate Ion (HCO3–) in Plasma
70%
Oxygen ( O2) Transport Dissolved in Plasma
1%
Oxygen ( O2) Transport Chemically Bound to
Hemoglobin in the RBC
99%
Oxyhemoglobin
- Forms when an oxygen molecule reversibly attaches to the heme group of hemoglobin
- Heme contains iron (Fe)
- Iron provides attractive force for O2
- Hb + O2 → HbO2
Lung (alveolar) or Body Cells?
Hb + O2 –> HbO2
Lungs (alveolar)
HbO2–>Hb + O2
Body cells
Hb + CO2 –> HbCO2
Body cells
HbCO2 –> Hb + CO2
Lungs (alveolar)
Rank the attraction of Hemoglobin attraction. (CO, CO2, O2)
1) Carbon monoxide (CO)
2) Oxygen (O2)
3) Carbon Dioxide (CO2)
Carbaminohemoglobin
-Forms when a carbon dioxide molecule reversibly attaches to the heme group of hemoglobin
-Heme contains iron (Fe)
-Iron provides attractive force for CO2
Hb + CO2 → HbCO2
Carboxyhemoglobin
-Forms when a carbon monoxide molecule irreversibly attaches to the heme group of hemoglobin
-Heme contains iron (Fe)
-Iron provides attractive force for CO
Hb + CO → HbCO
Carbonic Acid
-Forms in RBC when carbonic anhydrase catalyzes water to combine w/ carbon dioxide to form carbonic acid
CO2 + H2O → H2CO3
Bicarbonate Ion
-Forms in RBC when carbonic acid breaks down to release hydrogen ion & bicarbonate ion
H2CO3 → H+ + HCO3–
Chloride Shift in Tissue Capillaries
- As RBCs move through tissue capillaries, they take in carbon dioxide & release the bicarbonate ion to the plasma
- As the bicarbonate ion is released, chloride ion (Cl–) shifts into the RBC in order to replace the negative bicarbonate ion (HCO3–)
- Preserves charge balance in RBC
Chloride Shift in Pulmonary Capillaries
- As RBCs move through pulmonary capillaries, they take in the bicarbonate ion from the plasma & release carbon dioxide to the plasma
- As the bicarbonate ion (HCO3–) shifts into the RBC from the plasma, chloride ion (Cl–) shifts out of the RBC to the plasma
- Preserves charge balance in RBC
Bohr Effect on CO2 and O2 in blood
- ↑Carbon dioxide in blood
- Oxygen Dissociation Curve shifts to right
- Right-shift decreases ability of hemoglobin to hold oxygen
- Results in additional oxygen unloaded to cells
Bohr Effect on pH
- When pH is decreased, oxygen saturation decreased from 75% to about 65%
- This makes an extra 10% oxygen available during any increase in physical activity
Factors that Induce Hemoglobin to Unload Oxygen
These factors cause a right shift in the oxygen dissociation curve (↑oxygen unloaded)
1. ↑Temperature (Root Effect) 2. ↑H+ from acids (Bohr Effect) 3. ↑H+ from CO2 (Bohr Effect) 4. ↑2,3-diphosphoglycerate (DPG)
About the Pons (Respiratory Center Locations)
1) What 2 center does Pons contain?
2) primary or secondary respiratory center?
- Pons contains Pneumotaxic center
- Pons contains Apneustic center
- Both centers are SECONDARY respiratory centers
- They do not set the primary respiratory rhythm
- They both modify the basic respiratory rate
Medulla oblongata (Respiratory Center Locations) 1) Is it primary or secondary respiratory center?
- Medulla oblongata contains the medullary respiratory center
- This center is the PRIMARY respiratory center
- It does set the basic respiratory rate
- It is modified by both secondary respiratory centers in the pons
Respiratory Center Functions of Pneumotaxic
inhibits (–) inspiration
Respiratory Center Functions of Apneustic
stimulates (+) inspiration
Respiratory Center Functions of Medullary
stimulates basic breathing
Higher Brain Centers
-Cerebral motor cortex (brain) can bypass brain stem (respiratory center) controls
Examples:
*Voluntary breath-holding
*Taking a voluntary deep breath (inhalation)
*Removing a voluntary deep breath (exhalation)
Hering-Breuer Reflex
- Inflation reflex
- Lung stretch-receptors are stimulated by lung inflation
- During inflation, inhibitory signals are sent to the medullary inspiration center to end inhalation & allow expiration
- Prevents over-inflation of lungs
- Prevents damage to the alveoli
Irritant Reflex
- Pulmonary irritant reflex
- Irritants promote constriction of air passages
- ↓Air flow to prevent damage to the lungs caused by any irritant
- Inhalation is inhibited to prevent damage from inhaled irritants
Exercise
- Proprioceptors (stretch receptors) in skeletal muscles activate during exercise
- Proprioceptor activation causes:
- ↑Rate of breathing
- ↑Depth of breathing
Central Chemoreceptors
-CO2 levels are monitored by central chemoreceptors (brain stem)
>H+ cannot cross the blood-brain barrier
>Carbon dioxide in the blood diffuses into cerebrospinal fluid (CSF)
>Carbonic acid forms in the CSF
Result:
*↑Rate of breathing
*↑Depth of breathing
Peripheral Chemoreceptors
-H+ levels in the blood are monitored by the aortic bodies & carotid bodies
-If carbon dioxide is not removed (hypoventilation), peripheral chemoreceptors are stimulated (↑acidity/↓pH)
Result:
*↑Rate of breathing
*↑Depth of breathing
Other Receptors- Hypothalamus
- Hypothalamus modifies rate & depth of respiration:
- Anger → ↓respiratory rate
- ↑Body temperature → ↑respiratory rate
- ↓Body temperature → ↓respiratory rate
Developmental Aspects of Respiratory Centers
-Respiratory centers are activated at birth
>Alveoli inflate
>Lung function begins
-Respiratory rate is highest in newborns & slows down into adulthood
-Lungs continue to mature
>More alveoli are formed until young adulthood
-↓Respiratory efficiency w/ ↑age
