Chapter 23 Respiratory
pulmonary ventilation
breathing
inhalation and exhalation of air between the atmosphere and the aveoli of the lungs
pulmonary ventilation
External Respiration
exchange of gases between the aveoli of the lungs and the blood in the pulmonary caoillaries
Internal Respiration
exchange of gases between blood in systemic capillaries and tissues
provides for gas exchange thru the intake of O2 and removal of CO2
funct of resp. system
Funct of resp. system
helps regulate blood pH
Contains receptors for sense of smell, filters inspired air, produces vocal sound, and excretes small amounts of water and heat
Funct of resp. system
conducting and respiratory zones
functional areas of respiratory system
Respiratory Zone
the main site of gas exchange and consists of the respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli
Conducting Zone
involved with bringing air to the site of external respiration and consists of the nose, pharynx, larynx, trachea, bronchi, bronchioles, and terminal bronchioles
filter air, warm air, moisten air, conducts air into the lungs
condcuting zone
bone framework of nose
fronta, nasal, maxillary bones
Nasal Conchae
subdivide the sides of nasasl cavity into grove-like passage ways called superior, middle. and inferior meatuses
increase surface area in the nose and prevent dehydration by trapping water droplet during exhalation
Nose conchae
Internal nares/choane
the openings that connect the nasal cavity to the pahrynx
External Nares
two openings on the undersurface of the external nose
leads into nasal vistubules
External Nares
Nasopharynx
respiratory passage
lies posterior to nasal cavity and extends to the soft palate
nasopharynx
oropharynx
involved in respiratory and digestive systems
posterior to the oral cavity adn extends from the soft palate inferiorly to the level of the hyoid bone
oropharynx
larynopharynx
involves respiratory and digestive system
begins at the level of hyoid bone and extends to the esophagus
laryngopharynx
soft palate and uvula
pull superiorly to close off the nasophrynx and prevent foods and liquids from entering the nasal cavity
larynx
voice box
short passage way that connects the pharynx to trachea
larynx
composed of nine pieces of carilage
larynx
arytenoid cartilage (layrnx)
most important bc they influence changes in the vocal folds for speech
Thryroid cartilage (larynx)
adam's apple
consists of two fused plates of hyaline cartilage that form the anterior portion of larynx
thyroid cartilage
Cricoid cartilage
superior-vestibular folds
inferior-vocal folds
Vestibular Folds (larynx mucus membrane)
not involved in voice production
function in holding the breath in the thoracic caivty (ex: lifting something heavy)
vestibular folds
vocal folds
main structures for voice production which occurs by opening and closing the rima glottidus
Epiglottis
flap of elastic cartilage covere with a mucus membrane
Carina
internal ridge located at the junction of the two mainstem bronchi
sensitive area for triggering the cough reflex
carnina
increases during activity such as exercise, causes relaxation of smooth muscle in bronchioles dilating the airway and increasing ventilation
Bronchioles (SNS)
Bronchioles (PNS)
causes constriction of smooth muscles in bronchioles (ex. asthma attack)
Cardiac Notch
in the left lung (indentation for the heart) makes the left lung 10% smaller than the right lung
Type I Alveolar Cells (Alveolus Wall)
simple squamous epithelium; most numerous
allow exchange of gases with the pulmonary capillaries
Type I Alveolar Cells
Type II Alveolar Cells (alveolus wall)
secretes surfactant that lowers the surface tension of the alveolar flid which reduces the tendency of the alveoli to collaspe
Respiratory Membrane
1. Type I and II Alveolar Cells
2. Epithelial Basement Membrane
3. Capillary Basement Membrane that is often fused to the epithelial basement membrane
4. Capillary endothelium
Pulmonary Ventilation
air flows between the atmosphere and the alveoli of the lungs bc of alternating pressure differences created by contraction and relaxation of respiratory muscles
the pressure of a gas in a closed container is inversely proportional to the volume of chamber; if the size of the container is increases, the pressure of the gas inside the container decreases
Boyle's Law
Inhalation
before the air pressure in lungs is equal to atmospheric pressure, air must be less in lungs than atmosphere
lung size must increase by contraction of diaphragm, the phrenic nerve flattens diaphragm, then external intercostal muscle contract, increasing the size of thoracic cavity
Inhalation
Exhalation
pressure in lungs is greater than the atmospheric pressure
passive as inspiratory muscles relax; active during forceful breathing
exhalation
Dorsal Respiratory Group (DRG)
collection of neurons in the medullary respiratory center for inspiration
compliance
refers to how much effort s needed to stretch the lung and chest walls
high-lungs and chest wall will expand easily; low-lungs and chest wall will resist expansion
compliance
related to elasticity and surface tension
compliance
Infant Respiratory Distress Syndrome
common problem in premature babies where surfactant production is not sufficient to support normal lung function
7%-plasma
23% CO2 carried by Hb inside RBCs as carbominohemoglobin
70% CO2 transported as HCO3-
CO2 Transport
Chloride Shift
in exchange for HCO3- moving into the blood plasma, chloride ions (CI-) move from plasma into the RBC to maintain the electrical balance
Carbonic anhydrase
enzyme that reacts with water when CO2 diffuses into RBC to form carbonic acid which in turn disassociates into H+ and HCO3-
H2O+CO2--H2CO3--H+HCO3-
carbonic anhydrase
Haldane Effect
the lower the amount of oxyhemoglobin, the higher CO2 carrying copacity of the blood
Ventilation-Perfusion Coupling
unique feature of pulmonary blood vessels is the ability to constrict during hypoxia
diverts blood from poorly ventilated areas of the lungs to welll ventilated area to increase gas exchange efficiency
Ventilation-perfusion coupling
increase in CO2, decreases HB affinity for O2
factors affecting the affinity of Hb for O2
decrease in pH, decrease in Hb affinity for O2
factors affecting the affinity of Hb for O2
factors affecting the affinity of Hb for O2
Increase in BPG, decrease in Hb affinity for O2
factors affecting the affinity of Hb for O2
fetal Hb has greater affinity than adult Hb
Partial pressure differences of the gases (affects gas exchange)
alveolar O2 pressure must be greater than blood oxygen pressure for O2 to diffuse from aveoli into the blood
any pulmonary disorder that decreases the surface area of alveoli for gas exchange decreasing the rate of external respiration
factor that affect gas exchange
diffusion distance (factors affect gas exchange)
greater the dffusion distance, the larger the decrease in rate of diffusion
CO2 outflow is much faster than O2 input
Molecular wt and solubility of gasses (factors affect gas exchange)
Central chemoreceptors
respond to changes in H+ and/or concentration of CO2 in the cerebrospinal fluid
Peripheral Chemoreceptors
sensitive to changes in O2, H+, adn CO2 in the blood
forceful exhalation
DRG and VRG inactive
neurons of VRG send nerve impulses to the accessory muscles which then contract resulting in a forceful exhalation
forceful exhalation
pre-Botzinger complex
VRG-a group if neurons that are involved in the generation of rhythm breathing
Normal quiet breathing
the DRG sends impulses to the diaphragm via phrenic nerve and the external intercostal muscles via the intercostal nerves
Surface tension
thin layer of alveolar fluid coatsthe luminal surface of alveoli adn exerts force