Respiratory system abridged Flashcards
Organs of respiratory pathway
- Nose
- Pharynx
- Larynx
- Trachea
- Main Bronchi
- Lungs – alveoli
Surfactant
- Lipid fat molecule made by cuboidal alveolar cells
- Coats gas-exposed alveolar surfaces so alveoli don’t collapse between breaths
- 28 to 30 weeks in pregnancy
- Dysfunctional to functional lungs
As we age, what happens to our lungs?
- Chest becomes more rigid and lungs slowly lose their elasticity
- By age 70, VC decreases by about 1/3
- More susceptible to sleep apnea
- Ciliary activity of the mucosa decreases
- More at risk for respiratory tract infections (pneumonia and influenza)
Physical factors that influence respiratory rate
- Exercise (more signals to resp. muscles)
- Increased body temperature (increase rate)
- Nonrespiratory movements
What does Pons do for respiratory system?
- Smooth out basic rhythm of breathing set by Medulla
Eupnea
- Normal breathing rate
- 12-15 respirations/minute
What does Medulla do for respiratory system?
- Sets basic rhythm of breathing via pacemaker
- Stimulates diaphragm and intercostal muscles
- Helps maintain eupnea (normal breathing)
Which nerves transmit respiratory messages from CNS?
- Phrenic
- Intercostal nerves
How is carbon dioxide transported in blood?
- Most transported in plasma as bicarbonate ion
- Smaller amount is transported inside RBCs bound to hemoglobin
- For it to diffuse out of blood into alveoli, must be released from bicarbonate form
- Bicarbonate ions enter RBCs and combine with hydrogen to make carbonic acid, this splits to form carbon dioxide and water; carbon dioxide diffuses from blood into alveoli
How is oxygen transported in blood?
- Most transported by RBC, via attachment to hemoglobin
- Very small amount is dissolved in plasma and transported that way
Nonrespiratory Movements: Yawn
Very deep inspiration
Nonrespiratory Movements: Hiccups
Sudden inspirations resulting from spasm in diaphragm
Nonrespiratory Movements: Laughing
- Release of air in a number of short expirations
- Primarily an emotionally induced mechanism
(same as crying)
Nonrespiratory Movements: Crying
- Release of air in a number of short expirations
- Emotionally induced mechanism
(same as laughing)
Nonrespiratory Movements: Sneeze
Same as cough, but upward air expels through nose
Nonrespiratory Movements: Cough
- Taking a deep breath, closing glottis, forcing air superiorly against glottis
- Glottis opens and blast of air is rushed upwards
- Acts to clear lower passageways
Inspiration/Inhalation
- Diaphragm/external intercostals contract
- Thoracic cavity increases
- Lungs adhere to thoracic walls
- Intrapulmonary volume increases
- Gases in lungs spread out
- Decrease in gas pressure in lungs creates parietal vacuum
- Air is sucked into lungs until pulmonary pressure equals atmospheric
Exhalation
- Inspiratory muscles relax
- Rib cage descends & lungs recoil
- Thoracic volume decreases
- Gases in lungs forced closer
- Intrapulmonary pressure raises higher than atmospheric pressure
- Gas flows out of lungs to equalize pressure
Pulmonary respiration
- “breathing”
- Air moves in and out of lungs so that gases in alveoli are continuously refreshed
Internal respiration
- At systemic capillaries, gas exchanges made between blood and tissue cells
External respiration
- Gas exchange between pulmonary blood and alveoli
- Alveoli always have more oxygen than blood
Cellular respiration
- Cornerstone of all energy-producing chemical reactions in body
- Actual use of energy by cell
- Making energy from fats, carbs, proteins
Protective mechanism: laryngal cartilages
Protects pathways
Protective mechanism: Alveolar macrophages
- “dust cells”- pick up bacteria, carbon particles, and other debris
Pathway of air from main bronchi to blood
- Bronchi
- bronchioles
- terminal bronchioles
- alveolar duct
- alveoli
Lungs
- Without mediastinum, lungs occupy entire thoracic cavity
- Site of gas exchange at respiratory membrane
- Apex is deep to clavicle; base rests atop diaphragm
- Covered with pulmonary/visceral serosa
- Stroma is mainly elastic connective tissue
Main Bronchi
- Formed by division of trachea
- Right bronchus is wider, shorter, and straighter
- Only warm, mostly cleansed, and well humidified air passes through bronchi
Nose
- Only exterior part of Resp. System
- First line of defense when filtering out air
- Palate separates it from oral cavity
- Sinuses lighten the skull
Pharynx
- Passageway for food and air, about 5 in.
- Nasopharynx > oropharynx > laryngopharynx > larynx
- Tonsils in nasopharynx and oropharynx
- Ear infections may follow sore throat
Larynx
- “Voice box”
- Routes food/air into proper channels
- Epiglottis, thyroid cartilage, vocal folds, cricoid cartilage
- Vestibular/Vocal folds formed by mucous membrane (Glottis between the two)
How is a cough triggered?
If anything other than air enters the larynx
Effect of hyperventilation on blood pH
- Decreased carbon dioxide retention
- Decreased carbonic acid
- Increase pH, leading to alkalosis
Effect of breathing into a bag on blood pH
- Increased carbon dioxide retention
- Increased carbonic acid
- Decrease pH, leading to acidosis
Intrapulmonary pressure relative to atmospheric pressure
- Negative during inspiration
- Positive during exhalation
- Intrapleural pressure is always negative*
