Final Pt. 2 Flashcards
Functions of the respiratory system?
Pulmonary ventilation (Air in and out), external resiprayion (O/CO between blood and tissues)
Function of circulatory system?
Transport of O2/CO2 in blood
Internal respiration ( exchange of O2/CO2 between blood vessels & tissues)
The function of nose and paranasal sinus? (5)
Provides airway, moistens air, filters air chamber for speech/smell, mucous catches bacteria
Chonchae? (3)
Bone in nose, increase mucosal area, enhance air turbulence and heat, reclaim heat
What is the pharynx?
Funnel shaped tube made of skeletal muscle, connects nasal cavity and mouth to larynx (Nasophraynx, oropharynx, laryngopharnyx)
Nasopharynx?
Posterior to nasal cavity, cilitated pseudostartified columnar epithelium, soft palate closes
Oropharynx?
Passage for food/air (soft palate to epiglottis), stratified squamous
Laryngophraynx?
Posterior to upright epiglottis (to larynx), startified squamous
Larynx? (3)
Opens laryngopharynx, continues to trachea. provides airway, routes air and food, voice
Trachea?
Extends from larynx to mediastinum, divides into 2 bronchi
3 layers of trachea
Mucosa, Submucosa, Adventitia
Bronchi?
Right and left main bronchi, branch into lobar bronchi, branch into segmental bronchus (keep divinding), less than 1.0 mm diameter, terminal bronchioles less than 0.5 mm
Lungs?
Made of root, apex, and base, hilum
Left lung has superior/ inferior lobes
Right lung has superior/middle/inferior lobes, furthur divided into bronchopulmonary segment
WHat is pulmonary circulation?
Pulmonary arteries deliver venous blood from heart to lungs for oxygenation
Pulmonary veins carry oxygenated blood from respiratory zones back to heart
Long pressure, high volume
Bronchiol arteries/ veins?
Bronchial arteries provide oxygenated blood to lung tisue
Bonchial viens anastomose with pulmonary veins
Innervation of lungs?
Parasymp. constriction
Sym. Dialation
What are pleura?
thin serosal membrane that divides the thoracic cavity into two plural compartments/ mediastinum
Different types of pleura? (3)
Parietal pleura: membrane on thoracic wall, face of diaphragm, around heart, between lungs
Visceral pleura: membrane on external lung surface
Pleural fluid fills slit-like plural cavity
4 different pressures?
Patm = pressure exerted by air surround the body, respiratory pressures relative to
Ppul = pressure in alveoli, fluctuates with breathing
Pip= pressure in pleural cavity
Ppul- Pip= pressure that keeps lung spaces open
What is pulmonary ventilation?
inspiration/expiration
depends of volume changes in thoracic cavity, volume change leads to pressure change
Boyle’s Law: P1V1=P2V2
What is expirations?
Inspiratory muscles relax, thoracic volume decreases, lungs recoil, air flows out of lungs down pressure gradient until (Ppul=Patm)
Forced inspirations can occur during exercise or with pulmonary disease, accessory muscles activated to increase thoracic cage size
What are alveoli?
Terminal bronchioles feed into respiratory bronchioles, lead into alveolar ducts, alveolar sacs
What is the respiratory membrane?
Blood air barrier, consists of alveolar and capillary walls along basement membranes
allows gas exchange by simple diffusion
single layer simple squamous epithelium, scattered cuboidal, pores equalize pressure
What is dead space?
Does not contrivbute to gas exchange, air remains in passageway, or space occupied by non functional aveloi
External Respiration
Diffusion gases between blood and lungs
Internal Respiration
Diffusion of gases between blood and tissues
Tissue Po2 is lower then in arterial blood, oxygen moves from blood to tissues
Tissue Pco2 is higher than in arterial blood, CO2 moves from tissues into blood
Venous blood returning to heart is 40 mm Hg Po2 and 45 mm Hg Pco2
3 factors affecting external respiration gas exchange?
Partial pressure gradients and gas solubility, thickness and surface area of respiratory membrane, ventilationn-perfusion coupling
Action of the diaphram
when diaphragm contracts, it moves inferiorly and flattens out, increase thoracic volume
Action of the intercoastals
when external intercostals contract, rib cage is lifted up and out, increased thoracic volume
3 factors that influence air passage?
Airway resistance, Alevolar surface tensoin, lung compliance
Pneumonia/ ephysema
Pneumonia: lungs become waterlogged, thickness of respiratory membrane increases, tissues become oxygen deprived
Emphysema: alveoli walls break down, surface area decreases
2 ways molecular O2 is carried?
1.5% dissolved in plasma
98.5% loosely bound to each Fe of hemoglobin
(deoxyhemoglobin) created
As O2 binds, Hb changes shape, increasing its affinity for O2
Influence of Po2 on hemoglobin saturation
In systemic arterial blood Po2 is 100 mm Hg, Hb 98% saturated
In systemic venous blood Po2 is 40 mm Hb, Hb is 75% saturated
Other factors that affect O binding to HB (4)
Temp (heat decreases affinity), pH, Pco2, concentration of biphosphoglycerate
Declining blood pH and increasing Pco2 cause HB-O2 bond to weaken
Three forms of CO2 transport?
Dissolved in plasma as Pco2 (7 to 10%)
Chemically bound to hemoglobin (20%)
As bicarbonate ions in plasma (around 70%)
What do O and CO2 bind to?
Most O2 attached to Heme, most CO2 attached to globin
Why is so much Co2 converted to bicarbonate
In systemic capillaries, after HCO3 is created, it quickly diffuses from RBCs into plasma
In pulmonary capillaries, the process occurs in reverse
HCO3 moves into RBCs while Cl (transits through) RBCs into plasma
HCO3 binds with H to form H2CO3, split by carbonic anhydrase into CO2 and water
CO2 diffuses into alveoli
What is the haldane effect?
Amount of CO2 transported is affected by Po2
The lower the Po2 and hemoglobin O2 saturation, the more CO2 can be carried in blood
Encourages CO2 exchange at tissues and at lungs
Carbonic acid-bicarbonate buffer system helps…
blood resist changes in pH
What is hypoxia?
inadequate O2 delivery to tissues, can result in cyanosis and is classified by cause
Different types of hypoxia (5)
Anemic hypoxia, Ischemic hypoxia, Histotoxic hypoxia
Hypoxemic hypoxis, Carbon monoxide poisioning
How does breathing affect blood
Shallow breathing increases CO2, drop in pH
Deep breathing decreases CO2, rise in pH
Neural controls for respiration?
Neurons in reticular formation of medulla and pons
Medullary respiratory centers: Ventral respiratory group and dorsal respiratory group
Ventral respiratory group?
network of neurons from spine to pons
Sets up eupnea, normal respiratory rate and rhythm
Inspiratory neurons excite inspiratory muscles via phrenic and intercostal nerves
Rate determined by how long center is active
Dorsal group?
Network of neurons near cranial nerve IX
Integrates input from peripheral stretch/ chemoreceptors, sends info to vrg neurons
Pontine respiratory centers?
Neurons modify activity of VRG to smooth transition between inspiration/expiration
Transmit impulses to VRG that fine-tune breathing rhythms
3 factors that control respiration?
Chemicals, Higher brain centers, reflexes
Chemicals?
Levels of chemicals sensed by central and peripheral chemoreceptors
If blood levels rise, CO2 accumlates in brain and becomes carbonic acid
Causes drop in pH, increased H stimulates chemoreceptors
Respiration increases and speeds up
Influence of PO2:
Peripheral chemoreceptors sense arterial O2 levels
Substantial drop in arterial PO2 to stimulate increased ventilation
Slight effect on ventilation because of huge O2 reservoir bound to Hb
Higher brain centers?
Hypothalamic controls: act through limbic system to modify rate/ depth of respiration
Cortical controls: direct signals from cerebral motor cortex that bypass medullary controls
Reflexes?
Pulmonary irritant reflexes: receptors in bronchioles respond to irritants, promote construction of air passages
Inflation reflex: Hering-Breuer reflex, stretch receptors in pleurae and airways stimulated by lung inflation, send inhibtoary signals to end inhalation/ allow expiration
