Lecture 9 Flashcards
What are the two types of respiration?
Internal and external
What is internal respiration?
Within the cell: CO2 produced (glycolysis) - Krebs cycle - O2 consumed (oxidative phosphorylation)
What is external respiration?
Ventilation: Exchange and transport of gases around the body
What does respiration rely on?
diffusion
Which systems act together for respiration?
Cardiovascular system (blood), Respiratory system ( lungs), the nervous system (breathing control)
What is the conducting zone comprised of?
Nose (nasopharynx), mouth (oropharynx), pharynx, larynx, trachea, bronchial tree, anatomical dead space (does not cover respiration)
How many generations of branches are there in the conducting zone?
16
What does the conducting zone do?
Provide pathways to get air to and from respiratory system
What is the respiratory zone comprised of?
Alveolar air spaces
What does the respiratory zone do?
Gas exchange
What are the functions of the conducting zone?
Conditions the incoming air; Filter e.g. hair in nose, mucus, Traps bacteria and particles
Warm: implication on solubility of gases, prevent problems
Humidify: prevent airways from drying out
What is the bronchial wall reinforced with and why?
Cartilage; prevents airway from collapsing
What is the bronchial wall comprised of besides cartilage?
Layer of smooth muscle: Controls airway diameter Big impact on resistance of airflow Mucous glands: On epithelial layer Produces secretions that trap particles Elastic tissue
What comprises the respiratory epithelium?
Ciliated epithelia (cilia maintains fluid beating), goblet cells (release mucins, helps develop mucous layer), sensory nerve endings (may be reacting to noxious chemicals)
How small are the diameters of the bronchioles?
Less than 1mm
Do the bronchioles have cartilage?
no
What are the bronchioles lined by?
respiratory epithelium
What is the diameter controlled most by?
smooth muscle
What is the Air Blood Barrier?
A “sandwich” created by flattened cytoplasm of type 1 pneumocyte and the capillary wall
What needs to happen for gaseous exchange?
Multiple barriers have to be crossed
What factors ensure gas exchange?
Large surface area Close contact with capillary walls Production of surfactant Gas has to pass several different barriers Bind to hemoglobin Maintaining small distances
What are the two processes of ventilation?
inspiration and expiration
What kind of muscles does quiet inspiration involve?
Primary muscles of inspiration: diaphram and external intercostals
What effect do the primary muscles of inspiration have?
Increases lung and thoracic volume
What law does air movement follow
Boyle’s law
What is Boyle’s law?
The increase in volume leads to a reduction in pressure. Air moves into the lungs down the pressure gradient. Volume increases and pressure decreases in a closed circuit, so air moves down pressure gradient
What muscles does forced inspiration involve?
Primary muscles, accessory (or secondary) muscles of inspiration
What are the accessory muscles of inspiration?
Scalenes, sternocleidomastoids, neck and back muscles, upper respiratory tract muscles (muscles contract to help pull the ribcage up)
What are the primary muscles of expiration?
There are none; quiet expiration is a passive process involving elastic recoil)
What muscles does forced expiration use?
Accessory muscles, internal intercostals (pulls ribcage back together), abdominal muscles, neck and back muscles
What is the pleural cavity filled with?
secretions
What are the functions of the pleura?
Prevents lungs from sticking to the chest wall
Enables free expansion and collapse of lungs (movements coordinated, subatmospheric pressure in pleural space)
What does the elastic nature of lungs tend them to do?
Collapse inwards
What does the elastic nature of lungs tend the chest wall to do?
Expand
What is a result of the elastic forces at rest?
The pressure in the intrapleural space is smaller than atmospheric pressure
What are the steps that occur in a pneumothorax?
- Puncture of pleural membrane of chest wall
- Atmospheric air in pleural space
- Ptp = Pa - Pip
(Ptp: transpulmonary pressure, Pa = alveolar pressure, Pip = Intrapleural pressure) - Lungs collapse down
- Have to seal lung
- Gradually reinstates negative pressure
