respiratory system Flashcards
Pulmonary ventilation
volume of air going into lungs from environment via mouth & nose
External Respiration
exchange of O2 and CO2 b/w lungs and blood
Internal Respiration
exchange of O2 and CO2 b/w blood and cells
Two structures of pulmonary system
- Conductive Zone: nose, mouth, nasal cavity, trachea, pharynx, bronchioles
- air transport - “anatomical dead space”
- warms/humidifies air and filters air using ciliated mucosal membranes
- Respiratory Zone: respiratory bronchioles, alveolar ducts, alveolar sacs, alveoli
- does not always function- “physiological dead space”
- gas exchange
What are the basic mechanics involved in breathing and how does Boyle’s Law work to aid breathing?
- pressure gradient
- resistance
Boyle’s Law: if temperature is constant then volume and pressure are inversely related
What are the major inspiratory and expiratory muscles at rest? During heavy exercise?
major muscles @ rest:
inspiratory: diaphragm, external intercostals, posterior serrate, scalenes
expiratory: passive - diaphragm relaxes & elastic return of lungs
major muscles during exercise:
inspiratory: same as resting but with faster contractions
expiratory: rectus abdominis, transperce abdominal, internal intercostals
Describe the pulmonary circulation and bronchial circulation
pulmonary circulation: external respiratory, parallels divisions of conductive zone and capillary blood matches lung structure
- R ventricle to pulmonary A to lungs to pulmonary V to L atrium
bronchial circulation: small systemic arteries
- aorta to lungs to pulmonary V to L atrium
What are the dynamic lung volumes?
FEV1: forced expiratory volume in 1 sec (80% of VC)
FEV3: forced expiratory volume in 3 sec (all of VC)
MVV: maximal ventilatory volume (maximal air exchange in 15-20 secs)
How does Dalton’s Law influence partial pressures of oxygen at different altitudes, i.e., sea level vs Pikes Peak?
There is the same amount of oxygen but at different barometric pressures
Sea Level: PO2 = 760mmHg x 0.2093 = 159 mmHg
PO2: lungs(104mmHg ) – blood(95mmHg) – cells(40mmHg)
Pikes Peak: PO2 = 440mmHg x 0.0293 = 99mmHg
PO2: lungs(40mmHg) – blood(40mmHg) – cells(45mmHg)
What are the two major respiratory centers located in the medulla oblongata and how do they function?
Inspiratory: most important center; rhythmical on/off depolarization of phrenic nerve
Expiratory: maintains inspiratory muscle tone and activates expiratory muscles during exercise
What are the other two respiratory centers located in the Pons and how do they function?
Apneustic: constantly stimulates inspiratory center unless inhibited by pneumotaxic center
Pneumotaxic: constantly inhibits inspiratory center and sometimes the apneustic center
Define and describe ATPS, BTPS, and STPD.
ATPS: ambient temp, pressure, saturated
BTPS: body temp, pressure, saturated
STPD: standard temp (0C) pressure (760mmHg) dry (0% humidity)
Discuss the five factors affecting control of pulmonary ventilation.
- Hypothalamus: involuntary action of SNS shock/pain inhibits & strong emotions stimulate
- Cerebral Cortex: provides a direct connection b/w motor cortex & respiratory muscles allowing for some voluntary action
- Systemic Receptors: in conduction zone of lungs resulting in reflex coughing/sneezes; deep/fast breathing inhibits apneustic and inspiratory centers
- Mechanoreceptors: proprioceptors in muscles & joints with no role at rest and only minor role during exercise
- Chemoreceptors: respond to chemical substance changes
- central: in medulla responds to increased PCO2 and acidity
- peripheral: in carotid A and aorta responds to increased PO2, K+ ions, acidity, and decreased PCO2 and pH
Discuss the four factors affecting diffusion across the alveolar-capillary membrane
- Solubility Coefficients (Henry’s Law): a mix of gases diffuses into a liquid in proportion to partial pressure & solubility coefficients until reaching equilibrium
- Diffusion Gradients: the larger the gradient, the faster the diffusion (excluding CO2)
- Membrane Thickness: increases in thickness reduces diffusion
- Alveolar Surface Area: decreases in surface area will decrease gas exchange
Discuss the different ways in which O2 can be transported and how to calculate oxygen content of arterial blood
- dissolved in plasma (1-3%)
- binds to heme portion of hemeoglobin (98%)
CaO2 = (SaO2 x Hb x binding constant) + (PaO2 x solubility coefficient)
