Respiration.

Question 1

Describe the different processes of respiration. Breathing, Gas exchange (internal), Gas transport, Gas exchange (external), (Usage of O2 to make ATP)

Answer 1

• Breathing
  
  • no exchange
  • ventilatin = air movement (only in the conduction zone), no exchange of gasses
• Gas exchange (external)
  
  • lung alveoli with blood capillaries
• Gas transport
  
  • Hemoglobin for O2 and bicarbonate for CO2
• Gas exchange (internal)
  
  • blood capillaries with tissue cells (body except lung)
• Usage of O2 to make ATP
  
  • cellular respiration uses O2 to produce ATP

Question 2

What are the functions of respiratory system?

Answer 2

1. Respiration (gas exchange)
2. Sound production
   
   1. via larynx
3. Odor detectin (olfactory sense)
   
   1. sensory nerves with nerve endings and immobile cilia
4. pH regular
5. Effects blood pressure
   
   1. respiratory pump - influences venous return
   2. ACE –> converts Ang 1 to Ang 2 Vasoconstriction

Question 3

Describe the changes in cell epithelium as you progress through the respiratory system.

What do goblet cells do?

Answer 3

• Starting with pseudostratifeid ciliated columnar cells
  
  • Relatively resistant to deflection
  • More importantly contains goblet cells
  • Goblet cells produce Mucin, mixes with water, allows mucus to be transported, for moisturing the epithelium and also for humidifying the air coming in, and moving particulate matter down to be coughed up or swallowed.
• Simple cilitated columnar epithelium
• simple ciliated cuboidal epithelium
• simple squamous epithelium
  
  • single layer basement membrane thats located in the alveoli
• Exception non-keratinized stratfied squamous epithelium
  
  • mouth and oropharynx
• General structure
  
  • The mucosa is composed of epithelium resting on a basement membrane and underlying lamina propria which is composed of areolar connective tissue.

Question 4

What is cellular structure of the upper respiratory tract/paranasal sinuses

What is its function?

Answer 4

• Continuous with the nasal cavity, sinuses, into the nasopharynx
• Structure
  
  • lined by pseudostratified ciliated columnar epithelium continuous with nasal cavity mucosa
  • Mucus swept into the pharynx and swallowed
• Function
  
  • warm, humidify clean incoming air
  • lighten the weight of the skull
  • give resonance to the voice.

Question 5

What is the mucociliary escalator?

Answer 5

• Cillia move against the airflow towards the pharynx, starting in the trachea to the bronchioles.
  
  • sweeps mucus towards towards the larynx so particulate matter and mucus can be removed.
  • Coordinated movement of the cilia is termed the escalator.
• Cilia sweep toward the pharynx to be swallowed or coughed up

Question 6

Describe the distribution of cartilage throughout the respiratory tract starting with the trachea. What is its function?

Answer 6

1. Trachea
   
   1. contains C-shaped rings that hold the trachea open without energy expenditure
   2. posterior side you have a muscular layer/smooth muscle layer that is part of the boundary between the esophagus and the trachea.
2. Left and right main bronchus
   
   1. Cartilage starts to become full rings.
3. lobar bronchi
   
   1. full rings start to become cartilaginous plates
4. segmental bronchi –> smaller bronchi
   
   1. inside the lobe of a lung, start to get less and less cartilaginous plates
5. Bronchiole –> Terminal bronchiole –> respiratory bronchiole –> alveoli
   
   1. respiratory bronchiole, no cartilage, all smooth muscle.

Question 7

What nervous system is responsible for bronchoconstritction/dilation

Answer 7

Dilation = sympathetic

constriction = para

Question 8

Describe the path of air once it reaches respiratory bronchiole. How does the bronchiole get its blood supply?

Answer 8

1. Respiratory bronchiole –> alveolar duct –> alveoli
2. Alveoli is where external gas exchange is going to occur
3. Bronchioles recieve their blood supply from the systemic circulation, not the pulmonary artery.

Question 9

What is the respiratory zone? What occurs here?

Answer 9

1. Respiratory bronchiole
2. alveoli
3. respiratory membrane
4. We have pockets of cells 4-5
   
   1. they include capillaries, alveolar type I and Type II cells.
   2. Type I = respiratory membrane
   3. Type II = produce surfactant
   4. Also have macrophages in this area
      
      1. phagocytize anything that shouldn’t be there
   5. Also have alveolor pores in the septum of alveoli
      
      1. allows air to move from one alveoli to another based on pressure
5. the alveolar epithelium (primarily type I cells) is fused with the endothelial endothelium in a basement membrane
   
   1. this means that there is only 3 layers that the gas exchange has to go through
   2. More than 3 layers, slows down gas exchange - ie fluid in the lungs.

Question 10

Describe the function of the following 4 systems in regards to the lungs.

Pulmonary circulation

bronchial circulation

lymph drainage

autonomic nervous system

Answer 10

1. Pulmonary circulatoin
   
   1. replenishies oxygen and eliminates CO2, pulm veins can recieve blood from bronchiole veins
2. bronchial circulation
   
   1. part of systemic circulation (thoracic transports oxygenated blood to bronchi and bronchioles (aorta)
3. Lymph drainage
   
   1. within the lung, around the bronchi and in the pleura.
      
      1. collects particles and pollutatns not removed by the cilia
4. autonomic nervous system innervates
   
   1. larynx => innervated only by PNS, vagus nerve
   2. Trachea and bronchial tree => sympathetic and parasympathetic I.
   3. Lungs => sympathetic (exits T1-T5, sympathetic chain) causes bronchodilation
      
      1. parasympathetic, vagus n, usually bronchoconstriction

Question 11

Describe the location of pleural membranes, whats inbetween them?

Answer 11

1. Visceral pleura - on the lungs themselves
2. parietal pleura - on the thoracic cavity
3. In between there is a pleural cavity, this cavity is filled with fluid.
   
   1. these cavities are seperated, on each side. Helps with if there is damage to one or if there is infection. this is called compartmentalization

Question 12

Describe the 4 respiratory processes?

Answer 12

1. Pulmonary ventilation
   
   1. Air containing CO2 is exhaled
   2. air containing o2 is inhaled
2. Alveolar gas exchange
   
   1. o2 moves into the blood
   2. this is termed external gas exchange
3. gas transport
   
   1. blood containing o2 is moved throughout the body
4. systemic gas exchange
   
   1. o2 moves into the systemic cells
   2. Co2 then moves into the blood
   3. this is termed internal gas exchange
5. gas transport
   
   1. blood containing co2 moves through the body and back into the lungs
6. alveolar gas exchange
   
   1. Co2 moves into the alveoli where it can be exchanged with o2 once again.

Question 13

What is pulmonary ventilation based on?

Answer 13

1. Based on a respiratory cycle
   
   1. Single cycle of inspiration and expiration
      
      1. inspiration –> active process (muscle contraction)
         
         1. leads to lung expansion –> increased volume
         2. affects pressure –> initially decreasing pressure in pleural cavity –> translates to a decrease in pressure in the lung itself, air comes in.
      2. expiration - passive process (muscle relaxation)
         
         1. leads to decrease in lung volume
         2. increases pressure and air moves out.
2. Normal respiratory rate is termed Eupnea
   
   1. 12-15 breaths/min
   2. Gas pressure and volume –> inverse relationship

Question 14

Why does the lung remain inflated?

Answer 14

• The lung remains inflated because intrapulmonary pressure is greater than intrapleural pressure.
• The intrapulmonary pressure is great enough that it puts pressure against the intrapleural cavity and causes it to remain inflated.

Question 15

Describe the pressures in the lung during quiet inspiration and quiet expiration.

Answer 15

• Quiet inspiration
  
  • intrapulmonary pressure is equal to atm pressure
    
    • atm = 760 mmHg
    • intrapleural pressure = 756 mmHg
    • intrapulmonary pressure = 760 mmHg
  • Intrapulmonary pressure becomes less than the atomospheric pressure; air flows in.
    
    • air flows in ~500mL in a quiet breath
    • intrapleural cavity volume increases, and pressure decreases 754mmHg
    • alveolar volume increases, intrapulmonary pressure decreases. 759mmHg
• quiet expiration
  
  • intrapulmonary pressure = atm pressure
  • intrapulmonary pressure becomes greater than the atmospheric pressure and air flows out.
    
    • Pleural cavity volume decreases, pressure increases 756mmHg
    • alveolar volume decreases, pressure increases, air flows out 761mmHg

Question 16

What are the muscles used in quiet breathing and forced breathing including inspiration and expiration.

Answer 16

1. Quiet breathing
   
   1. diaphragm
   2. external intercostal
2. Forced breathing
   
   1. inhalation
      
      1. sternocliedomastoid
      2. scalene muscles
      3. seratus posterior and superior
      4. pec minor
      5. erector spinae
   2. exhalation
      
      1. transverse thoracis
      2. serratus posterior inferior
      3. internal intercostal
      4. external oblique
      5. transversus abdominal.

Question 17

What are the three changes in volume that occur with the thoracic cage? What do these establish?

Answer 17

• Volume changes lead to pressure changes, establishes a gradient for airflow
• Boyle’s law - inverse pressure and volume relationship
• Vertical changes
  
  • Diaphragm contracts and vertical demensions of the thoracic cavity increase
  • diaphragm relaxes and vertical dimensions of thoracic cavity narrow
• lateral changes
  
  • ribs are elevated and thoracic cavity widens
  • ribs are depressed and thoracic cavity narrows
• anterior/posterior changes
  
  • inferior portion of the sternum moves anteriorly and the thoracic cavity expands
  • inferior portion of the sternum moves posteriorly and the thoracic cavity compresses

Question 18

Review the respiratory volumes and capacities.

Answer 18

Tidal volume = normal respiration ~500

Inspiratory reserve volume - max air you can take in after a normal inhalation

inspiratory capacity - from exhale to biggest breath

expiratory reserve volume - volume left in lungs after normal breath

residual volume - volume in lungs you can’t exhale

Functional residual capacity - ERV +RV

Note - capacities always include more than 1 measurement

Volume = specific measurement

Question 19

What are factors influencing airflow?

Answer 19

1. Resistance => bronchial tree and trachea = variable resistance (mucus)
   
   1. variable resistance via the autonomic NS
      
      1. bronchodilation = sympathetic
      2. bronchoconstriction = parasymp
2. Compliance - how easily the lung expands, influecned by factors that cause resistance to distension
   
   1. surface tension (influenced by the amount of surfactant)
   2. elasticity of lung tissue (tendency to return to initial size)
   3. mobility of the thoracic cage
3. alveolar ventilation (ml/min) = air vol./breath x respiration rate
   
   1. get a ml/breath
   2. Eupnea = 12-15 breath/min
   3. air volume = tidal volume - anatomical dead space (-physiological dead space)

Question 20

What is the general concept of the law of laplace?

Answer 20

1. Law of lapace states that pressure in the alveolus is directly proportional to surface tension; and inversely related to the radius of the alveoli
   
   1. thus, pressure in smaller alveoli would be greater than in larger alveoli, if ST were the same in both
   2. greater pressure of smaller alveollus would cause it to move its empty air into the larger one. This occurs through bronchioles

Question 21

Describe this picture in generation of breathing.

Answer 21

1. Respiratory center in the cerebral cortex.
   
   1. Motor output coming from the cerebral cortex goes down through midbrain through the pontine respiratory center and then goes to the skeletal muscles of breathing.
      
      1. phrenic nerve to the diaphragm
      2. intercostal nerves to the intercostal muscles
   2. If you need more breath in
      
      1. still coming from the respiratory center of the cerebral cortex but then also going to the accessory muscles.
2. Other sensory receptors
   
   1. irritant receptors in the lungs, baroreceptors,
   2. proprioceptors - in the skeletal muscle, all tell the lungs to breath a little faster.
   3. These have input into the dorsal respiratory group.
3. Also have chemoreceptors
   
   1. central chemoreceptors that detect changes in pH/Co2 or bicarb levels in the CSF
      
      1. these send information to the pontine respiratory center.
4. chemoreceptors in the carotid bodies and the aortic arch,
   
   1. peripheral chemoreceptors, detects increased CO2, increased H+ and decreased O2
   2. This information goes to the Dorsal respiratory group.
5. DRG sends impulses to VRG
   
   1. this sends impulses to increase breathing.

Question 22

Control of breathing - sensory

Answer 22

1. Input to the respiratory centers
   
   1. chemoreceptors - CO2, O2, pH
      
      1. central: in medulla oblongata
      2. peripheral: carotid and aortic bodies
   2. proprioceptors
      
      1. muscles and joints –> activity and mobility
   3. stretch receptors
      
      1. vagus nerves –> decreases breathing depth
   4. irritant receptors
      
      1. in respiratory epithelium of conduction zone (mucosa)

Question 23

Control of breathing - REGULATION

Answer 23

1. Brain stem respiratory centers
   
   1. medulla oblongata
      
      1. VRG –> sets rhythym, 2 sec inhalation/3 sec exhalation
      2. DRG –> influences by senosry neurons (adjusts rhythm)
   2. pontine respiratory group
      
      1. override (crying)
2. Higher centers: hypothalamus, limbic system, cerebral cortex.

Question 24

Terminology for respiratory rhythm

Answer 24

1. eupnea –> relaxed quiet brething characterized by tidal volume 500ml and respriatory rate of 12-15
2. apnea - temporary cessation of breathing
3. dyspnea - labored, gasping breathing; shortness of breath
4. hypercapnea - increased rate and depth of breathing in response to exerise, pain, or other conditions
5. hyperventilatoin - increased pulmonary ventilation in excess of metabolic demand (respiratory alkalosis, decrease CO2)
6. hypoventilatino - reduced pulmonary ventilation
7. Kussmaul respiratoin - deep, rapid breathing, often induced by acidosis (diabetes)
8. orthopnea - dysnpnea that occurs when a person is lying down
9. respiratory arrest - permanent cessation of breathing
10. hypercapnia - elevated PCO2 in the blood >43mmHG
11. Hypocapnia - low PCO2 in the blood <37 mmHg

Question 25

Gas exchange and transport. Gas diffusion - what is daltons law? Alveolar air versus inspired air?

Answer 25

• Gas diffusion is based on a couple of principles
  
  • composition of air (partial pressure)
    
    • Dalton Law: sum of all partial gas pressure = total gas pressure
  • Alveolar air versus inspired air.
    
    • N2
      
      • inspired 78.6% 597mmHg
      • alveolar 74.9 596mmHg etc
    • look at picture.

Question 26

What are the factors that influence external respiration? –> ie alveolar gas exchange.

Answer 26

1. Difference in partial pressure
   
   1. Po2 = 104-40mmHg
      
      1. comes in at 40, leaves at 104mmHg
   2. PCo2 = 40-45 mmHg
      
      1. comes in at 45, leaves at 40
2. Solubility of gas
   
   1. CO2 >>>> O2
3. At steep gradients
   
   1. there will be rapid diffusion (Hyperbaric chamber 100%o2)
4. At reduced gradients
   
   1. there will be slower diffusion (air at 10k feet)
5. During gas exchange
   
   1. both gases diffuse down their concentration gradient until the partial pressure of each gas in the air is equal to the partial pressure in the capillary/water
   2. Oxygen specifically, the higher partial pressure of oxygen in the air favors its diffusion into the water and film of the alveoli, it lowers solubility and slows down the process
      
      1. equilibration time in the blood is 0.25sec
      2. at rest RBC transit time is 0.75 sec to pass through the capillary; RBC transit time with vigourous exercise is 0.3sec
         
         1. transit time is usually not a factor in healthy individuals
6. Membrane thickness
   
   1. if the membrane gets thicker, pneumonia, gas diffusion becomes slower
7. total surface membrane
   
   1. changes in emphysema - confluent alveoli
8. ventilation perfusion coupling
   
   1. regulates air flow, blood flow
   2. autonomic NS influences both

Question 27

Describe ventilation perfusion coupling

Answer 27

1. Under circumstances where there is increased CO2 inside the air (inside the bronchiole)
   
   1. the bronchiole will dilate (so we can get rid of the CO2)
   2. the capillary bed will constrict
2. Under circumstances where there is decreased CO2 inside the bronchiole
   
   1. the bronchiole will constrict, can direct air that is low in CO2 to areas that are higher in CO2
   2. the capillary bed will dilate
3. If there is increased PO2, or decreased PCO2
   
   1. the arterioles will dilate
4. If there is decreased PO2, or increased PCO2
   
   1. the arterioles will constrict.
5. In general
   
   1. Changes in bronchiole diameters
      
      1. High CO2 leads to increased ventilation of the area, because blood brings CO2
   2. Changes in arteriole diameter
      
      1. high oxygen leads to high perfusion of the area b/c there is lots of oxygen to pick up

Question 28

Describe external respiration (alveolar gas exchange)

Answer 28

Depends on, pressure gradient, solubility, membrane thickness, total surface area, ventilation perfusion coupling

Question 29

Describe the four things that can enhance the release of oxygen. How does this translate to hemoglobin curve.

Answer 29

1. increase temperature –> decrease affinity between o2 and Hg
2. increase H+ –> “ “ (Bohr effect)
3. Increased 2,3 BPG –> “ “
4. Increased CO2 –> “ “

Decrease affinity shifts the curve to the right. Increase affinity shifts the curve to the left.

Question 30

Describe internal respiration

Answer 30

1. Opposite of external respiration, have to travel through different membranes too.
   
   1. Co2 from the blood and O2 from tissue cells have to travel through their plasma membrane, the interstitial fluid, and then the capillary endothelium.
2. Co2 enters the RBC, CO2 and H20 join together via carbonic anhydrase forming H2CO3, this splits into HCO3- and a hydrogen ion.
3. HCO3- leaves the cell and Cl- enters, chloride shift.

Question 31

What are the different imbalnces that can occur in regards to ventilation?

Answer 31

1. Hydrogen/carbon dioxide are the main regulators of ventilatory rate
2. oxygen imbalance –> hypoxia
   
   1. hypoxemic hypoxia
      
      1. low oxygen in the blood (ventilation/respiratory problem) as cause of low tissue oxygen (ie low PO2 or low external exchange)
   2. ischemic hypoxia (circulatory)
      
      1. no or low blood flow to tissue as cause
   3. Anemic hypoxia
      
      1. low oxygen carrying ability in the blood (ie carbon monoxide)
   4. histotoxic hypoxia
      
      1. toxic agent such as cyanide or alcohol –> decreased ATP production, tissue does not use oxygen.