Describe the anatomy of the Respiratory System
made up of two parts
Nose,Nasal Cavity,Pharynx,Larynx,Trachea Bronchi,Bronchioles,Terminal Bronchioles
Respiratory Bronchioles,Alveolar Ducts, Alveoli
What does the respiratory system do?
Delivers O2 to the Blood
Removes CO2 from the Blood
Differentiate between the respiratory zone and conducting zone organs. What do they do?
The conducting zone is the pathway that gets air down to the lungs, while the Respiratory zone is where gas exchange takes place.
List the pathway that an air molecule would take to get to an alveolus.
- Nasal Cavity
- Pharynx (naso, oro, laryngo)
- Bronchi primary
- Bronchioles secondary
- Alveolar Ducts
List the three divisions of the pharynx.
Describe the anatomy of the larynx, including the hyoid.
- The larynx attaches superiorly to the hyoid bone, opening into the laryngopharynx, and attaches inferiorly to the trachea.located between pharynx and trachea
- Hyoid bone anchors the larynx
- vestibular fold true vocal chord
- laryngeal prominence or adams apple.
- Thyroid cartilage
- vocal fold false vocal chord
- Cricoid cartilage
- the glottis is the opening into the trachea and is for air under normal circumstances.
- .Tracheal cartilages
Describe tracheal histology.
- pseudostratified columnar epitheleaium faces towards lumen)
- goblet cells in 1rst layer
- hyaline cartilage
- smooth muscle
Describe the bronchial tree.
The bronchial tree is an essential part of the respiratory system. It consists of several interacting structures, such as the bronchi, bronchioles, and alveoli. These structures work together to provide a network system between the lungs and the trachea. Without this system, a person could not breathe properly.
they are the primary or bronchi, secondary or bronchioles, and tertiary.
splits 23 times getting smaller each time.
More smooth muscle present as it gets smaller.(bronchodialation/constriction)
terminal bronchial ends in smallest possible airway and it ends in a respritatory bronchiole. which is covered in alveoli which is where gas exchange takes place.
Describe how gas exchanges occur between the pulmonary capillaries and the alveoli
pulminary capilary linked to p vein.
- Gas exchange depends on:
- 1. Partial pressures and gas solubilities
- 2. Ventilation-Perfusion Coupling
- 3. Thickness and surface area of respiratory membrane
- Gas is exchanged between the alveoli and the pulmonary capillaries via diffusion: gas molecules will move from an area of high concentration to an area of low concentration.
- The partial pressure of oxygen (PO2) is lower in the alveoli in comparison to the external environment, which allows for diffusion of oxygen into the alveoli.
- The partial pressure of carbon dioxide (PCO2) is higher in the capillaries than in the alveoli, which allows for diffusion into the alveoli where it is exhaled during expiration.
- The ventilation/perfusion ratio (V/Q) ensures that the ideal amount of blood and gas is received by the alveoli for efficient gas exchange
Describe the anatomy of the respiratory membrane
The respiratory membrane consists of a single layer of simple squamous epithelium. one layer thick tunca intima - one layer on capillary wall one layer on aveolar wall so each together makes 2 layers of simple squamous cells.
what cavity contains the lungs?
thoracic pleural cavity
Describe the pleural membranes within the lungs.
Pleural space with fluid fluid reduces friction when breathing.
- too much is pulmonary edema
- too little is pleurisy.
Distinguish between atmospheric pressure (ATM) and intrapulmonary pressure.
- pressure changes in the lungs which influences whether air can move in / out
- when the pressure inside lung is 756 for example the lungs will allow air to come in because the pressure inside the lung is less than that outside.
- this happens and creates a pressure gradient because pressure always moves high to low.
- ATM atmospheric pressure is 760 mmhg it is constant does not change.
- Atm is the pressure that is being forced from the outside against the lung.
- Intrapulmonary pressure can change it is NOT constant.
Pressure recorded within the alveoli
Changes with inspiration / expirationabout 1 mm Hg, back and forth at rest
Attempts to equalize with atmospheric pressure: 759 mm Hg 760 mm Hg
Describe the two basic laws that influence air movement.
Intrapulmonary pressure is the pressure in the alveoli, which rises and falls during respiration, but always eventually equalizes with atmospheric pressure.
Intrapleural pressure is the pressure in the pleural cavity. It also rises and falls during respiration, but is always about 4 mm Hg less than intrapulmonary pressure.
Dalton’s Law of Partial Pressures Relates gas pressure to gas
2. At a gas-liquid interface: Henry’s Law Relates gas dissolved in water to gas concentration and solubility, and temperature
The total pressure exerted by a mixture of gases is the sum of the
pressures exerted independently by each gas in the mixture.
The pressure exerted by each gas– its partial pressure—is directly proportional to its percentage in the mixture.
Pressure is the force exerted on the wall of a container by the
particles contained within it.
As the volume of a container (lung) s
the pressure in the container s…OR
As the volume of a container (lung) s,
the pressure in the containers.
P1V1 = P2V2
The volume of gas that will go into solution at a given partial
pressure depends onto its solubility in the liquid (plasma) and
CO2 = very solubleO2 = 1/20 as soluble as CO2N2 = virtually insoluble
Less in solution as temperature increases
list and describe the 4 processes of respiration.
- Pulmonary Ventilation
bringing air in and out
2. Gas Exchange pulmonary capillary and alveolus systemic capillaries and tissues
3Transport of Respiratory gases
4.Control of Respiration
What muscles are involved in inspiration and expiration?
1.Diaphragm, scalenes, external intercostals contract
2. Contraction:diaphragm drops intercostals/scalenes move
rib cage UP and OUT
lung volume: RISES intrapulmonary pressure: FALLSair flows: IN to equalize with ATM
diaphragm: moves up
intercostals/scalenes relax: rib cage in and down
2. lung volume: FALLS intrapulmonary pressure: RISES air moves: OUT to equalize with ATM
3. Forced expiration: contraction abdominal muscles
3 factors that increase energy required to breathe.
1.Increase airway resistance
2.Increase alveolar surface tension
3.Decrease lung compliance
what factors could cause the increased energy required to breathe?
airway resistance- Blocked passageways: tumor, mucus Bronchiole constriction: parasympathetic stimulation via irritants or histamine
surface tension-water molecules sticking to the alveoli ir sac which cause it not to inflate (pnemonia)
decrease lung compliance- lungs cannot stretch like they should Compliance: Increased fibrosis, decrease in flexibility of thoracic cage, low surfactant
What is a surfactant and what does it do?
The remarkable property of the surfactant which coats the alveoli is that it reduces the surface tension by a factor of about 15 so that the 1 mmHg pressure differential is sufficient to inflate the alveoli.
describe and give the normal values for: TV,IRV,ERV,VC,RV,TLC
TV - 500ml
IRV - 3100 ml
ERV - 1200 ml
VC - 4800ml forced exhale TV+ERV+RV=
RV - 1200ml air left remaining in the lungs non exchangeable air
TLC - 6000 ml total amount of air exchangeable and non exchangeable.
compute minute or total ventilation
General measure of health: total ventilation rate
Minute or total ventilation: V = (ml of air/ breath ) ( # breaths / min)
V = (500 ml air) (12 breaths per min) = 6000 ml per minute
Compute alveolar ventilation rate and why is this preferred to minute or TV
AVR= deadspace times breaths per minute
AVR accounts for anatomical dead space
AVR = (TV-dead space)(# breaths/min)
AVR = (500ml-150ml)(12 breaths/min)
= (350 ml)(12 breaths/min)
= 4200 ml/min
AVR is a better measure of health than total ventilation. How so?
Good minute ventilation may not mean good alveolar ventilation
2 People Can Have Same Total Ventilation: One Healthy, One Near Death
Very briefly describe Daltons law and Henrys law. List the composition of air.
Dalton’s law of Partial Pressures (Px mm Hg)-
- The total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas in the mixture. The pressure exerted by each gas- it’s partial pressure-is directly proportional to its percentage in the mixture.
✩ Dalton’s Law of partial pressures in a mixture of gases relates gas pressure to gas concentration. Slide 40/Pg 847
Henry’s law (Gas Solubility) Pg 824
- The volume of gas that will go into a solution at a given partial pressure depends on its solubility in the liquid (plasma) and temperature.
- less in solution as temperature increases
✩ Henry’s Law at a liquid-gas interface relates gas dissolved in water to gas concentration, solubility, and temperature. Slide 40
22b. List the composition of air. Slide 40
Oxygen (O2), Carbon Dioxide (CO2), Nitrogen (N2)
- Nitrogen is the most common and more abundant
Describe the solubilities of CO2, O2, N2
- Carbon Dioxide (CO2) = very soluble
- Oxygen (O2) = 1/20 as soluble as Carbon Dioxide (CO2)
- Nitrogen (N2) = virtually insoluble
Note: Less insoluble as temperature raises
Differentiate between external and internal respiration
External respiration is between lungs and blood concerning how O2 and CO2 are swapped:
- Oxygen (O2) goes from alveoli to blood.
- Carbon dioxide (CO2) goes from blood to alveoli.
Internal respiration is between the blood and tissue cells:
- Oxygen (O2) goes from blood to cell tissues.
- Carbon dioxide (CO2) goes from cell tissues to blood
How is Oxygen (O 2 ) and
Carbon Dioxide (CO 2 ) each
transported around the body?and what are their preferred modes of transport
O2 - Carried in two ways:1. Dissolved in plasma ~ 1.5% 2. Bound to hemoglobin
- Dissolved in Plasma (~10 %)
- Bound to Hemoglobin (~20%)
- As a Bicarbonate (HCO3) (~70 %)
Note: A Bicarbonate makes something “basic”.
CO2 travels through blood and O2 travels on Hb through blood.
How many O2 molecules can bind to 1 Hb molecule?
Up to 4 (4 is full)
Describe how changing PH and body temperature can affect the affinity of Hb for O2?
- If Ph and temp too high, Hb tells O2 goodbye
- If PH and temp too low, Hb just wont let go (of o2)
Describe the chloride shift
chloride shift. The movement of chloride ions from the plasma into red blood cells as a result of the transfer of carbon dioxide from tissues to the plasma, a process that serves to maintain blood pH.
describe the peripheral and central chemo-receptors and what they each each are measuring.
Peripheral Chemoreceptors sensitive to
O2, CO2, pH
1. In Arotic Arch
(via vagus nerves, X)
2. At bifurcation of Common Carotids (glossopharyngeal nerves, IX)
Central Chemoreceptors sensitive to H+
Brainstem, esp along medulla in contact with CSF
Describe the respiratory centers in the pons and medulla
Medullary centers set the basic rhythm of inspiration /
Inspire 2 seconds
Expire 3 seconds
Thought to be due to reciprocal inhibition
Brainstem centers activate neurons leading to:
Diaphragm via phrenic nerves
External Intercostals via intercostal nerves
Pontine centers modify rate and depth of breathing