Unit 6 Flashcards
– moving air into and out of
the lungs
Pulmonary ventilation
gas exchange between the
lungs and the blood
External respiration
transport of oxygen and carbon
dioxide between the lungs and tissues
Transport
– gas exchange between
systemic blood vessels and tissues
Internal respiration
Major Functions of the Respiratory System
Gas exchange
Regulation of blood pH
Voice production
Olfaction
Protection
Oxygen enters blood and carbon dioxide leaves
Gas exchange
Altered by changing
blood carbon dioxide levels (increase CO2 = decrease pH)
Regulation of blood pH
Movement of air past vocal folds makes sound and speech
Voice production
Smell occurs when airborne molecules are drawn into nasal cavity
Olfaction
Against microorganisms by preventing
entry and removing them from respiratory
surfaces
Protection
organs in upper tract of respi
nose, pharynx and associated structures
organs in lower tract of respi
larynx, trachea, bronchi, lungs and the tubing within the lungs
-Passageway for respiration
-Receptors for smell
-Filters incoming air to filter larger foreign material
-Moistens and warms incoming air
-Resonating chambers for voice
Upper Respiratory Tract
maintains an open airway, routes food and air appropriately, assists in sound production
Larynx
transports air to and from lungs
Trachea
branch into lungs
Bronchi
transport air to alveoli for gas exchange
Lungs
– Site of gas exchange
– Consists of bronchioles, alveolar ducts, alveolar sacs
and alveoli
Respiratory zone
– Provides rigid conduits for air to reach the sites of gas
exchange
– Includes all other respiratory structures
Conducting zone
diaphragm and other
muscles that promote ventilation
Respiratory muscles
The external portion of the nose is made of
___ and skin and is lined with __
- cartilage
- mucous membrane
formed by the frontal, nasal, and maxillary bones
bony framework of the nose
Cavities within bones surrounding the nasal
cavity: Frontal Bone, Sphenoid Bone,
Ethmoid Bone, Maxillary Bone
Paranasal Sinuses
Surface Anatomy of the Nose
- Root
- Apex
- Bridge
- External naris
superior attachment of the nose to the frontal bone
root
tip of the nose
apex
bony framework of the nose formed by nasal bones
bridge
nostril; external opening into nasal cavity
external naris
functions of paranasal sinuses
- Lightens the skull
- Acts as resonating chambers for speech
- Produce mucus that drains the nasal cavity
passageway for air
and food, provides a resonating chamber for
speech sounds, and houses the tonsils, which
participate in immunological reactions against
foreign invaders
Pharynx
-voice box is a passageway that connects the pharynx and trachea
-contains vocal folds
Larynx
produce sound when they vibrate
vocal folds
extends from the larynx to the primary bronchi
trachea
location of bronchi
At the superior border of the 5th thoracic vertebrae,
branching of bronchial tree
trachea
main bronchi
lobar bronchi
segmental bronchi
bronchioles
terminal bronchioles
- paired organs in the thoracic cavity
- enclosed and protected by the pleural membrane
Lungs
“air sacs” found within the lungs
alveoli
– form nearly continuous lining, more numerous than type II, main site of gas exchange, secrete Angiotensin Converting Enzyme (ACE)
Type I alveolar cells
– form nearly continuous lining, more numerous than type II, main site of gas exchange, secrete Angiotensin Converting Enzyme (ACE)
Type I alveolar cells
free surfaces contain microvilli, secrete alveolar fluid
(surfactant reduces tendency to collapse)
Type II alveolar cells (septal cells)
The respiratory membrane is composed of
- A layer of type I and type II alveolar cells and
associated alveolar macrophages that constitutes
the alveolar wall - An epithelial basement membrane underlying the
alveolar wall - A capillary basement membrane that is often
fused to the epithelial basement membrane - The capillary endothelium
It is the site of external respiration and diffusion of
gases between the inhaled air and the blood
Gas exchange
Blood enters the lungs via
pulmonary arteries (pulmonary circulation)
bronchial arteries (systemic circulation)
Blood exits the lungs via
pulmonary veins and the bronchial veins
-perfusion coupling
Ventilation
- Inhalation and exhalation
- Exchange of air between atmosphere and alveoli
Pulmonary ventilation/ breathing
- Exchange of gases between alveoli and blood
External (pulmonary) respiration
- Exchange of gases between systemic capillaries and tissue cells
- Supplies cellular respiration (makes ATP
Internal (tissue) respiration
Transport of oxygen and carbon dioxide via the bloodstream
Respiratory gas transport
flow of air into lung
Inspiration
air leaving lung
Expiration
– The volume of a gas varies inversely with its
pressure
-pressure of a gas in a closed container is
inversely proportional to the volume of the container
Boyle’s Law
Pressure inside alveoli must become lower than
atmospheric pressure for air to flow into lungs
- 760 millimeters of mercury (mmHg) or 1 atmosphere (1
atm)
-most important muscle of inhalation
* Flattens, lowering dome when contracted
* Responsible for 75% of air entering lungs during normal
quiet breathing
Diaphragm
- Contraction elevates ribs
- 25% of air entering lungs during normal quiet breathing
External intercostals
– Holds the pleural membranes together, which assists with lung expansion
– Surfactant reduces surface tension within the alveoli
Surface tension
– Pushing air out of the lungs
– Pressure in lungs greater than atmospheric pressure
– Normally passive – muscle relax instead of contract
Expiration
Expiration can be aided by:
Thoracic and abdominal wall muscles that pull the thoracic cage
downward and inward, decreasing intra-alveolar pressure
- Muscles included in inspiration
– External intercostals
– Diaphragm
accessory muscles inspiration
– Sternocleidomastoid
– Pectoralis minor
– Scalenes (neck muscles)
Muscles of inspiration relax
– The rib cage descends
– The lungs recoil
Breathing - Expiration
- It is an active process
– Occurs in activities such as blowing up a balloon, exercising, or yelling - Abdominal wall muscles are involved in forced expiration
– Function to ↑ the pressure in the abdominal cavity forcing the abdominal organs upward against the diaphragm
Expiration
Factors Affecting Pulmonary Ventilation
(1)Air pressure differences drive airflow
(2) Surface tension of alveolar fluid
(3) Lung compliance
– Inwardly directed force in the alveoli which must
be overcome to expand the lungs during each
inspiration
– Causes alveoli to assume smallest possible
diameter
– Accounts for 2/3 of lung elastic recoil
– Prevents collapse of alveoli at exhalation
Surface tension of alveolar fluid
- The ease with which the lungs may be expanded,
stretched, or inflated - Depends primarily on the elasticity of the lung
tissue
Lung compliance
refers to the ability of the lung to recoil after
it has been inflated
Elasticity
Results in difficulty resuming the shape of the lung during
exhalation
Emphysema
Results in difficulty expanding the lung because of increased
fibrous tissue and mucous
Cystic fibrosis
Opposition to air flow in the respiratory passageways
Airway Resistance
Airway Resistance examples
– Asthma
– Bronchospasm during an allergic reaction
release via the sympathetic nervous system dilates
bronchioles and reduces air resistance
Epinephrine
shallow chest breathing due to
contraction of external intercostals
Costal breathing
deep abdominal
breathing due to outward movement of
abdomen due to the contraction and descent of
the abdomen
Diaphragmatic breathing
Breathing Patterns and Respiratory Movements
- Eupnea
- Apnea
- Dyspnea
- Tachypnea
- Costal breathing
- Diaphragmatic breathing
Can be caused by reflexes or voluntary
actions
Non Respiratory Air Movements
Non Respiratory Air Movements examples
- Cough and sneeze
- Laughing
- Crying
*Yawn - Hiccup
total volume of air inhaled and exhaled each minute
Minute ventilation (MV)
Factors affecting respiratory capacity
size, sex, age, physical condition
tidal volume reaches respiratory zone
70%
30% of tidal volume remains in
conducting zone
conducting airways with air that does not
undergo respiratory gas exchange
Anatomic (respiratory) dead space
volume of air per
minute that actually reaches respiratory zone
Alveolar ventilation rate
Amount of air that can be taken in forcibly over
the tidal volume
Inspiratory reserve volume (IRV)
Amount of air that can be forcibly exhaled
Expiratory reserve volume (ERV)
Air remaining in lung after expiration
Residual volume
Residual volume
About 1200 ml
Expiratory reserve volume (ERV)
Approximately 1200 ml
Inspiratory reserve volume (IRV)
Usually between 2100 and 3200 ml (Ave = 3100
ml)
The total amount of exchangeable air
Vital capacity
Vital capacity formula
TV + IRV + ERV
Total Lung Capacity formula
Vital capacity + Residual Volume
Air that actually reaches the respiratory zone
Functional volume
Functional volume
*Usually about 350 ml
Air that remains in conducting zone and never
reaches alveoli
Dead space volume
Dead space volume
About 150 ml
Sounds are monitored with a stethoscope
Respiratory Sounds
produced by air rushing
through trachea and bronchi
Bronchial sounds
soft sounds of
air filling alveoli
Vesicular breathing sounds
Respiratory Sounds
Bronchial sounds
Vesicular breathing sounds
Bronchovesicular
– Each gas in a mixture of gases exerts its own pressure as if no other gases were present
– Total pressure is the sum of all the partial pressures
Dalton’s Law
Quantity of a gas that will dissolve in a liquid is
proportional to the partial pressures of the gas
and its solubility
Henry’s law
Oxygen movement into the blood
Carbon dioxide movement out of the blood
Blood leaving the lungs is oxygen-rich and
carbon dioxide-poor
External Respiration
- The alveoli always has more oxygen than the
blood
*Oxygen moves by diffusion towards the area of
lower concentration
- Pulmonary capillary blood gains oxygen
Oxygen movement into the blood
- Blood returning from tissues has higher
concentrations of carbon dioxide than air in the
alveoli - Pulmonary capillary blood gives up carbon
dioxide
Carbon dioxide movement out of the blood
External Respiration in Lungs: oxygen process
– Oxygen diffuses from alveolar air (PO2 105 mmHg) into blood of pulmonary capillaries (PO2 40 mmHg)
– Diffusion continues until PO2 of pulmonary capillary blood matches PO2 of alveolar air
– Small amount of mixing with blood from conducting portion of respiratory system drops PO2 of blood in pulmonary veins to 100 mmHg
External Respiration in Lungs: carbon dioxide process
– Carbon dioxide diffuses from deoxygenated blood in pulmonary capillaries (PCO2 45 mmHg) into alveolar air (PCO2 40 mmHg)
– Continues until of PCO2 blood reaches 40 mmHg
internal respiration occurs in
tissues throughout body
Internal Respiration: oxygen process
– Oxygen diffuses from systemic capillary blood (PO2 100 mmHg) into
tissue cells (PO2 40 mmHg) – cells constantly use oxygen to make ATP
– Blood drops to 40 mmHg by the time blood exits the systemic
capillaries
Internal Respiration: carbon dioxide process
– Carbon dioxide diffuses from tissue cells (PCO2 45 mmHg) into systemic
capillaries (PCO2 40 mmHg) – cells constantly make carbon dioxide
– PCO2 blood reaches 45 mmHg
internal respiration at rest
- only about 25% of the available oxygen is used
– Deoxygenated blood would retain 75% of its oxygen capacity
Rate of Pulmonary and Systemic Gas Exchange Depends on
– Partial pressures of gases
– Surface area available for gas exchange
– Diffusion distance
– Molecular weight and solubility of gases
Oxygen transport
– Only about 1.5% dissolved in plasma
– 98.5% bound to hemoglobin in red blood cells
Factors Affecting the Affinity of Hb for O2
- PO2
- pH
- Temperature
- Type of Hb
Relationship between Hemoglobin and Oxygen Partial Pressure
- Higher the PO2, More O2 combines with Hb
– Fully saturated
tense state; very difficult for
oxygen to gain access to the iron-binding sites
Deoxyhemoglobin
relaxed state of hemoglobin
Oxyhemoglobin
Cooperative binding
once an oxygen binds to one site, iron moves
slightly and so do parts of the peptide chains
attached to it, making it easier for the next oxygen
to bind until all 4 sites are occupied by oxygen
