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Ch 23 - Respiratory System

Terms in this set (105)

Functions of the respiratory System
Regulates blood pH
Production of chemical mediators
Voice production
Olfaction
Protection against some microorganisms
Nose
Consists of external nose and the nasal cavity
External Nose
Primarily hyaline cartilage, with bridge supported by nasal bones and extensions of the frontal bones and maxilla
Nasal Cavity serves as a
Passageway for air
Cleans and humidifies air
Location for sense of smell
The paranasal sinuses, functions as a resonating chamber for speech
Openings of the nasal cavity
-Nares open to the outside, and the chonae lead to pharynx ((throat)
-Paranasal sinuses and the nasolacrimal duct open into the nasal cavity
Parts of the nasal cavity
-Floor is formed by hard palate
-Divided by nasal septum
-Anterior vestibule contains hairs that trap debris
-Lined with pseudostratified ciliated columnar epithelium that traps debris and moves it to the pharynx
-Superior part contains olfactory epithelium
Pharynx
Opening for digestive and respiratory systems
THROAT
3 regions:
1) Nasopharynx
2) laryngopharynx
3) Oropharynx
Nasopharynx
-Posterior to choanae, ends at uvula of the soft palate
-Contains the openings to the auditory tube and the pharyngeal tonsils
What does the uvula do?
If it gets touched you throw up
Vomit out things you don't want in the body
Oropharynx
From soft palate to epiglottis
Contains the palatine and lingual tonsils
Laryngopharynx
From epiglottis to openings of the trachea and esophagus
Larynx
Passageway for air between pharynx and trachea, anterior throat
Has outer casing of 9 cartilages connected by muscles and ligaments
3 Unpaired Cartilages of the Larynx
Thyroid- largest, adam's apple
Cricoid - most inferior, base of larynx
Epiglottis - Attached to thyroid, has a flap near base of tongue
6 Paired Cartilages of the Larynx
1) Arytenoid, corniculate, and cuneiform
Why does the male voice change at puberty?
Thyroid cartilage protrudes so vocal cords elongate
Two pairs of ligaments span the interior larynx from anterior to posterior
1) Vestibular folds (superior)
2) Vocal folds (inferior)
Closure of both ensures that objects do not enter the trachea and can block the passage of air
Trachea
"Windpipe"
Membranous tube passing from larynx to main bronchi
-Dense regular CT and smooth muscle
-Walls reinforced with C shaped cartilage
-Smooth muscle forms posterior wall, separating it from esophagus. Contracts during high coughing to expel mucous.
Tracheobronchial Tree
Trachea divides to form: L/R bronchi and carina
Carina
Cartilage at bifurcation. Membrane of carina especially sensitive to irritation and inhaled objects initiate the cough reflex
Primary Bronchi take air to
R and L lung
Secondary Bronchi take air to
Lobes of lungs (2 in L, 3 in R)
Tertiary Bronchi take air to
Bronchopulmonary segments (9 in L, 10 in R)
(lobules and alveoli)
Tertiary Bronchi subdivide into
smaller bronchi, bronchioles, then terminal bronchioles
Cartilage in tracheobronchial tree
Holds tube system open, smooth muscle controls diameter
As tubes get smaller, cartilage decreases and smooth muscle increases
What is the principle respiratory organs?
Lungs
Lungs
Base rests of diaphragm, apex is superior to clavicle
-Things enter lungs at hilus
-Right lung has 3 lobes, L has 2 and cardiac notch
Lungs are divided into
Bronchiopulmonary segments, which are divided into lobules, which lead to alveoli
Alveoli
Chambers where gas exchange takes place between the air and the blood
Walls have elastic fibers
What 2 cells are alveoli made of?
-Type 1: pneumocytes (squamous epithelial)
-Type 2: pneumocytes, which produce surfactant (lowers surface tensions)
Respiratory Membrane
Part of the lungs where gas exchange between air and blood
-Thin layer of fluid lining alveolus
-Basement membrane ofAlveolar epithelium
-Thin interstitial space
-BM of capillary endothelium
Thoracic Wall
Comprised of bony and cartilagenious structures (thoracic vertebrae, ribs, costal cartilages, sternum) and various muscles. Responsible for ventilation
Ventilation
Air movement
Muscles of Inspiration
Contract to increase the volume of thoracic cavity
Diaphragm, external intercostals, pect minor, scalenes
Muscles of Expiration
Contract to decrease volume of thoracic cavity (passive)
-Internal intercostals, abdominal muscles
Pleural Membrane
Surround each lung seperately
Visceral pleura surrounds
lungs
Parietal Pleura lines the
INside of the thoracic cavity
Superior surface of the diaphragm
Lateral surface of mediastinum
Newly oxygenated blood leaves the
lungs to the heart via pulmonary veins
Deoxygenated blood travels from
the heart to the lungs via pulmonary arteries
Oxygenated blood that nourishes lung tissues is delivered via
bronchial arteries of systemic circulation
Ventilation (breathing) is dependent on
-Gas exchange between atmosphere and lungs
-Flow of air INTO and OUT of the lungs requires a pressure gradient
-Movement of air governed by Boyle's law
Boyle's Law
Assuming temperature is constant volume of gas varies inversely with pressure
Inspiration
-Diaphragm contracts and flattens so increase in vertical dimension of thoracic cavity (moves towards abdominopelvic cavity)
-External intervostals contract so increase in ant, post dimension of thoracic cavity
-Volume of pleural spaces increases
-Intra alveolar and intra pleural pressure decreases
-Air rushes from atmosphere into lungs
Expiration
-Diaphragm relaxes (gases go back into thoracic cavity)
-External intercostals relax (elastic recoil of lungs)
-Volume of pleural spaces decrease
-Intra alveolar and intra pleural pressure increases
-Air goes from lungs to atmosphere
If you contract the muscles of inspiration,
What happens to the volume of the pleural cavity?
Increases
If you contract the muscles of inspiration,
What happens to the pleural pressure?
Decreases (more -)
If you contract the muscles of inspiration,
What is the effect on the intra- alveolar volume?
increase
If you contract the muscles of inspiration,
What is the effect on the intra alveolar pressure?
Decreases
If you contract the muscles of inspiration,
what is the direction of air flow?
From atmosphere into lungs
If you contract the muscles of expiration,
What happens to the volume of the pleural cavity?
Decreases
If you contract the muscles of expiration,
What happens to the pleural pressure?
increases
If you contract the muscles of expiration,
What is the effect on the intra- alveolar volume?
...
If you contract the muscles of expiration,
What is the effect on the intra alveolar pressure?
increases
If you contract the muscles of expiration,
what is the direction of air flow?
Lungs to atmosphere
Measurement of lung function
Compliance of the lungs and thorax
Pulmonary volumes and capacities
Minute ventilation and alveolar ventilation
Compliance of the lungs and thorax
Greater the compliance, easier it is for a change in pressure to cause an expansion
Tidal Volume
Volume of air inspired or expired during normal respiratory cycles
Inspiratory Reserve Volume
Amount of air that can be inspired after normal tidal volume
Expiratory Reserve Volume
Amount of air that can be forcefully expired after expiration of normal tidal volume
Residual Volume
Volume of air remaining in lungs after most forceful expiration
Minimal Volume
Volume of air remaining in lungs after residual volume
Inspiratory Capacity
Tidal volume + inspiratory reserve volume
Functional Residual Capacity
Expiratory reserve volume + residual volume
Vital Capacity
Tidal volume + inspiratory reserve volume + ERV
Total Lung Capacity
TV + ERV + IRV + RV
Minute Ventilation
Total amount of air moved in and out of the respiratory system per minute
Dead space
is the part of the respiratory system where gas exchange does not take place
Alveolar Ventilation
How much air per minute enters the part of the respiratory system where gas exchange takes place
Partial Pressure
Contribution of gas to the total pressure of a mixture of gases ( Daltons Law)
% of the gas in the mixture X total pressure of the mixture
Diffusion of gases into and out of liquids
Concentration of a dissolved gas in a liquid is determined by its pressure and by its solubility coefficient (henrys law)
= partial pressure of the gas over the liquid X solubility coefficent
Diffusion of gases through the respiratory membrane depends on
A) Respiratory membrane thickness (must be thin)
B)Diffusion coefficient of the gas
C) SA of respiratory membrane (must be large)
D) Partial pressure gradient across the resp membrane
Most of the oxygen transported in the blood from the lungs is combined with the molecule
Hemoglobin in RBC
(rest in the plasma)
Oxygen moves from the alveoli into
The blood. Blood is almost completely saturated with oxygen when it leaves the capillary. Oxygen moves from tissue capillaries into the tissues
CO2 Partial Pressure Gradient
CO2 moves from tissues into tissue capillaries. CO2 moves from the pulmonary capillaries into alveoli
Oxygen is transported by _______ and is dissolved in _________
hemoglobin
Plasma
The oxygen hemoglobin dissociation curve shows the relationships between
Hb% saturation and PO2.
STEEP at low partial pressure
FLAT at high partial pressure
Hemoglobin almost completely saturated when PO2 is 80mm Hg or above.
At lower partial pressure, the hemoglobin
releases O2
High PO2 more O2 combines with Hb.
Curve Shifts to the
left
Low PO2 more O2 released from Hb:
Curve shifts to the
right
Hemoglobin's ability to hold oxygen decreases and the oxygen hemoglobin dissociation curve shifts to the right due to
v pH (Bohr effect)
^ H+
^ pCO2
^ temp
^ levels of BPG in RBC
v O2 = ^ CO2 = ^ H+ = v pH
hb deliver more O2
curve shifts to the right
% saturation hb decreases
Hemoglobin's ability to hold oxygen increases and the oxygen hemoglobin dissociation curve shifts to the left due to
^ pH (bohr effect)
v H+
v pCO2
v temp
At lungs
^ O2 = v CO2 = v H+ = ^ pH
hb picks up O2
Curve shifts left
% sat hemoglobin increases
Bohr Effect
Effect of pH on oxygen- hemoglobin dissociation curve
-As pH of blood declines amount of oxygen bound to hemoglobin at any given PO2 declines
-Occures bc decreased pH yields increase in H+ that combines with hemoglobin changing its shape and oxygen cannot bind to hemoglobin
If you increase BPG
Hemoglobin can't hold O2
BPG increases hemoglobin's ability to ________ oxygen
release
Fetal Hemoglobin
Higher affinity for oxygen than maternal hemoglobin does
Most of CO2 is transported as
HCO3-
What happens in tissue capillaries?
-CO2 enters blood plasma, and then most will enter RBC
-Inside RBC, CO2+ H20 -> H2CO3 requires carbonic anhydrase
H2CO3 dissociates to H+ and HCO3-
HCO3- exits RBC in exchange for Cl- entering the RBC from plasma (chloride shift)
H ions bind to hemoglobin
CO2 bound to hemoglobin (haldane effect)
Haldane Effect
Less oxygen is bound to hemoglobin, the more CO2, will bind to hemoglobin, and vice versa
Chloride Shift
HCO3- exits the RBC in exchange for Cl- entering the RBC from plasma
In pulmonary caps, what occurs in tissue caps
-CO2 diffuses from plasma and RBCs into alveoli
-HCO3- enters RBCs. Cl- exits
-INSIDE RBC, HCO3- + H+ > H2CO3
then H2CO3 > CO2 + H2O (requires carbonic acid)
-CO2 released from hb due to lower H+ and ^ O2
-More CO2 diffuses into alveoli
Medullary respiratory center consists of
-Dorsal respiratory group: stim contraction of diaphragm
-Ventral respiratory group: stim the intercostal and abdominal muscles
Pontine Respiratory Group is involved in
Switching between inspiration and expiration
Generation of Rhythmic Ventilation
-Neurons in the medullary respiratory center est the basic rhythm of ventilation
-When stimuli from receptors or other parts of the brain exceed a threshold level, inspiration begins
-As respiratory muscles stim, neurons that stop inspiration are stimulated. When the stimulation of these neurons exceeds a threshold level, inspiration is inhibited
Cerebral Control of Ventilation
Ventilation can be voluntarily controlled and can be modified by emotions
Herin Breuer Reflex
Stretch of the lungs during inspiration can inhibit the respiratory center and contribute to a cessation of inspiration - protective in babies
Effect of exercise on ventilation
COllateral fibers from motor neurons and from proprioceptors stimulate the respiratory centers
Other Modifications of Ventilation
Touch, thermal, and pain sensations can also modify ventilation
Decreased O2 is detected by receptors in the
carotid and aortic bodies, which then stimulate the respiratory center
What is the major regulator of ventilation?
CO2
Central chemoreceptor in
medulla oblongata
Peripheral chemoreceptor in
aorta and carotid
An ^ in CO2 or a v in pH can stimulate
the chemosensitive area, causing an ^ in rate and depth of ventilation
A decrease in CO2 or an increase in pH can result in a
decreased rate and depth of ventilation
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