Ex phys chapter 7 Flashcards
The purpose of the respiratory system is to
carry O2 to and remove CO2 from all body tissues
The 4 processes that carry out the respiratory process are
- Pulmonary ventilation (external respiration)
- Pulmonary diffusion (external respiration)
- Transport of gases via blood
- Capillary diffusion (internal respiration)
Pulmonary ventilation
is the process of moving air into and out of lungs (transport zone, and exchange zone)
At rest, air drawn into lungs through nose, but:
through mouth when demand exceeds
Nose/mouth → pharynx →
larynx → trachea → bronchial tree → alveoli
Lungs suspended by pleural sacs
- Parietal pleura lines ______wall
- Visceral (pulmonary) pleura attaches to lungs
- Lungs take size and shape of rib cage
thoracic
Anatomy of lung, pleural sacs, diaphragm, and rib cage determines:
airflow into and out of lungs
- Inspiration
- Expiration
inspiration is a ___ process.
active
Involved muscles in inspiration::
- _____ ______ move rib cage (up & out) and sternum (up & forward)
- ________ flattens down toward the abdomen
- External intercostals
- Diaphragm
Inspiration:
-Expands thoracic cavity in ____ dimensions
- Expands volume inside ______ cavity
- Expands volume inside lungs
- three
- thoracic
Lung volume ↑, intrapulmonary pressure ↓
- ______ law regarding pressure versus volume
- At constant temperature, pressure and volume inversely ______
- Boyle’s
- proportional
during respiration Air passively rushes in due to
pressure difference
Forced breathing uses additional muscles such as
____ _____ &_______ that
Raise ribs even farther
Scalenes, sternocleidomastoid, pectorals
expiration is usually a ____ process
passive
expiration: Usually passive process
- ______ muscles relax
- ____ ____ ↓, intrapulmonary pressure ↑
- Air forced out of lungs
- Inspiratory
- lung volume
when expiration is an active process (forced breathing):
- ____ ___ pull ribs down
- Also, ____ ____ & ____ ____
- Abdominal muscles force diaphragm back up
- Internal intercostals
- latissimus dorsi, quadratus lumborum
Respiratory pump
- Changes in intra-abdominal, intrathoracic pressure promote : ____
- Pressure ↑ → venous compression/squeezing
- Pressure ↓ → venous filling
venous return to heart
Milking action from changing pressures assists :
right atrial filling (respiratory pump)
pulmonary volumes:
Measured using
spirometry
pulmonary volumes: Measured using spirometry
- Lung volumes, capacities, flow rates
- _______– air entering & leaving the lungs
- _______ – greatest air volume expired
- _______ – air remained in lungs
- ________– sum of VC and RV
- Tidal volume
- Vital capacity (VC)
- Residual volume (RV)
- Total lung capacity (TLC)
spirometry
Diagnostic tool for respiratory disease
pulmonary diffusion is:
Gas exchange between alveoli and capillaries
Gas exchange between alveoli and capillaries
- Inspired air path: bronchial tree → arrives at _____
- Blood path: right ventricle → _____ → pulmonary arteries → pulmonary capillaries
- Capillaries surround alveoli
- alveoli
- pulmonary trunk
Pulmonary Diffusion Serves two major functions:
- Replenishes blood oxygen supply
- Removes carbon dioxide from blood
At rest, lungs receive ______ blood / min
~4 to 6 L
RV cardiac output = LV cardiac output
Lung blood flow = _______
systemic blood flow
Low pressure circulation
- Lung MAP = ___ mmHg versus aortic MAP = ___ mmHg
- Small pressure gradient (15 mmHg to 5 mmHg)
- Resistance much lower due to _______
- 15
- 95
- thinner vessel walls
Respiratory Membrane is also called
alveolar-capillary membrane
respiratory membrane Also called alveolar-capillary membrane is made up of
Alveolar wall
Capillary wall
Respective basement membranes
Respiratory membrane: Surface across which gases are exchanged:
-Very thin: _ to _ μm
-Large surface area: ___ alveoli in close proximity to blood
Maximizes gas exchange
- 0.5-4
- 300 MILLION
Pulmonary Diffusion:
Partial Pressures of Gases
Air=
79.04% N2 + 20.93% O2 + 0.03% CO2
Total air P:
atmospheric pressure
Individual P:
partial pressures
Standard atmospheric P =
760 mmHg
Dalton’s Law: total air P = PN2 + PO2 + PCO2
PN2 + PO2 + PCO2
PN2 = 760 x 79.04% = \_\_\_ PO2 = 760 x 20.93% = \_\_\_\_\_\_ PCO2 = 760 x 0.04% = \_\_\_\_\_\_
- 600.7 mmHg
- 159.1 mmHg
- 0.2 mmHg
Henry’s Law:
gases dissolve in liquids in proportion to partial P
Also depends on specific fluid medium, temperature
Solubility in blood constant at given temperature
Partial P gradient most important factor for
determining gas exchange
- Partial P gradient drives gas ____
- Without gradient, gases in equilibrium, no ____-
- Diffusion
- Diffusion
Atmospheric PO2 =
159 mmHg
Alveolar PO2 =
105 mmHg
Pulmonary artery PO2 =
40 mmHg
PO2 gradient across respiratory membrane: ____
Results in pulmonary vein PO2 ~100 mmHg
65 mmHg (105 mmHg – 40 mmHg)
Fick’s Law:
rate of diffusion proportional to surface area and partial pressure gas gradient
Ficks Law:
PO2 gradient: ___ mmHg
PCO2 gradient: __mmHg
- 65
- 6
Diffusion constant influences diffusion rate:
- Constant different for each gas
- CO2 _____ diffusion constant than O2
- CO2 diffuses _____ despite lower gradient
- Lower
- easily
O2 diffusion capacity
-O2 volume diffused per minute per 1 mmHg of gradient
-Note: gradient calculated from capillary mean PO2,
≈
11 mmHg
Resting O2 diffusion capacity
- 21 mL O2/min/mmHg of gradient
- 231 mL O2/min for 11 mmHg gradient
Maximal exercise O2 diffusion capacity
- Venous O2 ↓↓ → PO2 bigger gradient
- Diffusion capacity ↑ by three times resting rate
At rest, O2 diffusion capacity limited due to incomplete
lung perfusion
At rest, O2 diffusion capacity limited due to incomplete lung perfusion
- Only bottom ___ of lung perfused with blood
- Top ____ lung surface area → poor gas exchange
- 1/3
- 2/3
During exercise, O2 diffusion capacity ↑ due to more even _____
-lung perfusion
During exercise, O2 diffusion capacity ↑ due to more even lung perfusion
- Systemic blood pressure ↑ _____ top 2/3 perfusion
- Gas exchange over full lung surface area
-opens
Pulmonary artery PCO2
~46 mmHg
Alveolar PCO2 ~
40 mmHg
6 mmHg PCO2 gradient permits diffusion
- CO2 diffusion constant ___ times greater than O2
- Allows diffusion despite lower gradient
20
Oxygen Transport in Blood
Can carry ___ mL O2/___ mL blood
~__ L O2/__ L blood
> __% bound to hemoglobin (Hb) in red blood cells
- 20 & 100
- 1 & 5
- 98%
- 2%
O2 + Hb:
oxyhemoglobin
Hb alone:
deoxyhemoglobin
High PO2 (i.e., in lungs)
- Loading portion of O2-Hb dissociation curve
- ____ change in Hb saturation per mmHg change in PO2
Small
Low PO2 (i.e., in body tissues)
- Unloading portion of O2-Hb dissociation curve
- ____ change in Hb saturation per mmHg change in PO2
large
Blood pH
- More acidic → O2-Hb curve shifts to ____
- Bohr effect
- More O2 unloaded at acidic exercising Muscle
- Right
- Muscle
Blood temperature
- Warmer → O2-Hb curve shifts to ___
- Promotes _____ O2 unloading during exercise
- Right
- tissue
Maximum amount of O2 blood can carry
- Based on Hb content (___-___ g Hb/___ mL blood)
- Hb __ to __% saturated at rest (0.75 s transit time)
- Lower saturation with exercise (shorter transit time)
- (12-18 g Hb/100 mL blood)
- Hb 98 to 99% saturated at rest (0.75 s transit time)
- Lower saturation with exercise (shorter transit time)
Blood Oxygen-Carrying Capacity Depends on ___ ___ ____
1 g Hb binds ____ mL O2
Blood capacity: ___ to __ mL O2/100 mL blood
Anemia → ↓ Hb content → ↓ O2 capacity
- blood Hb content
- 1.34
- 16 to 24
Carbon Dioxide Transport in Blood is released as ___ from cells
waste
Co2 is carried in blood three ways:
- As bicarbonate ions
- Dissolved in plasma
- Bound to Hb (carbaminohemoglobin)
Bicarbonate Ion Transports __ to __% of CO2 in blood to lungs
60 to 70%
Carbon Dioxide Transport:
Bicarbonate Ion
-CO2 + water form carbonic acid (H2CO3)
- Occurs in ______
- Catalyzed by:
- Red blood cells
- carbonic anhydrase
Carbonic acid dissociates into bicarbonate
CO2 + H2O → H2CO3 → HCO3- + H+
H+ binds to Hb (buffer), triggers _____
Bicarbonate ion diffuses from red blood cells into __-
- Bohr effect
- plasma
Carbon Dioxide Transport:
Dissolved Carbon Dioxide:
-__ to ___% of CO2 dissolved in plasma
-When PCO2 low (in lungs), CO2 comes out of solution, diffuses out into _____
- 7 to 10
- alveoli
Carbon Dioxide Transport:
Carbaminohemoglobin:
___ to ___% of CO2 transported bound to Hb
20-33
Carbon Dioxide Transport: Carbaminohemoglobin: >Does not compete with \_\_\_\_\_\_ -O2 binds to heme portion of Hb -CO2 binds to protein (-globin) portion of Hb
O2-Hb binding
Carbon Dioxide Transport: Carbaminohemoglobin: Hb state, PCO2 affect CO2-Hb \_\_\_\_\_ Deoxyhemoglobin binds \_\_\_ easier versus oxyhemoglobin – ↑ PCO2 → easier CO2-Hb binding – ↓ PCO2 → easier CO2-Hb dissociation
- binding
- Co2
Bicarbonate Ion: Transports __- to __% of CO2 in blood to lungs
60 to 70%
CO2 + water form _______ (H2CO3)
Occurs in ______
Catalyzed by carbonic anhydrase
- carbonic acid
- Red blood cells
Carbonic acid dissociates into bicarbonate
- CO2 + H2O → H2CO3 → HCO3- + H+
- H+ binds to Hb (buffer), triggers ____ effect
- Bicarbonate ion diffuses from red blood cells into _____
- Bohr
- plasma
during carbon dioxide transport __ to __% of CO2 dissolved in plasma
7 to 10
When PCO2 low (in lungs), CO2 comes out of solution, diffuses into ___
alveoli to be exhaled
during Carbaminohemoglobin
20 to 33% of CO2 transported bound to ___
HB
Carbaminohemoglobin does not compete with ____
- O2 binds to heme portion of Hb
- CO2 binds to protein (-globin) portion of Hb
-O2-Hb binding
O2 binds to heme portion of Hb
CO2 binds to protein (-globin) portion of Hb