Respiratory 3 Flashcards
What is Eupnea
Ventilation
What happens during inspiration
Thoracic volume increases
Pump handle motion
Scalenes and upper external intercostals
Bucket handle motion
Lower external intercostals
What muscles are involved in quiet expiration
No muscles (passive)
What happens during expiration
Diaphragm relaxes, thoracic volume decreases
Lungs recoil, alveolar volume decreases, compresses gas molecules, pressure in alveoli increase
Air moves out into lower pressure atm
What is size of pressure gradients created by changes in alveolar volume in quiet breathing
Small
What happens as soon as muscles stop contracting
Pressure rises
Before inspiration what is the relationship between Patm and Palv
Equal
No pressure gradient, no air flowing
When is their no air movement
Quick between inspiration and expiration
As soon as muscles begin to contract what happens to pressure
It drops
What additional accessory or secondary muscles become activated during forced inspiration
- sternocleidomastoids
- neck and back muscles
- upper respiratory tract muscles
What do the sternocleidomastoids do during forced inspiration
Lift the sternum outward, contribute to water pump handle effect
What do neck and back muscles do during forced inspiration
Elevate pectoral girdle increasing thoracic volume and extend back
What do upper respiratory tract muscles do during forced inspiration
Decrease airway resistance by dilating pharynx and larynx
Muscles of forced expiration
Abdominal muscles
Internal intercostals
Triangularis sterni
Neck and back muscles
What do abdominal muscles do during forced expiration
Pushes some visceral organs upward and pushes diaphragm up
What do internal intercostals do for forced expiration
Create opposite bucket handle
What does triangularis sterni do for forced expiration
Pulls sternum inward, negative pump handle
What do neck and back muscles do for forced expiration
Lean over- reduction in thoracic volume
What is the lungs attached to
Pleural cavity- double walled sack that surrounds each lung
What exists inside intrapleural fluid
Subatmospheric pressure exists in because lungs want to recoil inward
What is parietal pleura attached to
Wall of thoracic cavity and diaphragm
What is attached to visceral pleura
Outer wall of lung
What is intrapleural pressure that holds lungs in open state
-3 mmHg
Below Patm
What happens to pleura during inspiration
Move parietal away from visceral created more negative pressure in intrapleural
Creates more vacuum for lungs to be drawn outward towards neg pressure
What do inspiratory muscles do to parietal pleura layer
- Pull parietal away from visceral layer
- Increase volume of intrapleural cavity and decrease intrapleural pressure
- Visceral layer drawn towards neg pressure
- Pulls lungs outward
What is pressure at end of quiet expiration
-3 mmHg
What is intrapleural pressure during inspiration of quiet breathing
-4 to -6 mmHg
What happens with intrapleural pressure during inspiration
Intrapleural volume increases
Causes from in intrapleural pressure to more negative
Lungs drawn to more negative intrapleural pressure and thus expand
If cavity is larger what happens to pressure
Decreases
Complete steps of inspiration
- Diaphragm and inspiratory intercostals contract
- Thoracic cavity expands
- Intrapleural pressure becomes more subatmospheric
- Lungs expand
- Palv becomes subatmospheric
- Air flows into alveoli
All steps of expiration
- diaphragm and inspiratory muscles stop contracting
- Chest wall recoils inward
- Intrapleural pressure moves back to -3
- Lungs record towards preinspiration size
- Air in alveoli becomes compressed
- Palv becomes greater than Patm
- Air flows out of lungs
What is a pneumothorax
Collapse of lung due to interruption of normal intrapleural pressure
Need neg pressure to hold lungs open
What happens when theirs an interruption in intrapleural pressure
Pneumothorax (collapsed lung)
What are 2 types of pneumothorax
Traumatic (parietal or visceral or both)
Spontaneous (lung and visceral pleura ruptures)
What is the degree of lung expansion at any time proportional to
Change in pressure
Lung compliance
Stretchibility of lungs
How much any given change in pressure expands
What is lung elastance
Elastic recoil
Reciprocal of compliance
Ability to resist being deformed
What causes ease of expansion and more difficult expansion
More compliant - easier
Decreased compliance - harder
If high compliance what is elastance
Low
Easy to inspire, difficult to expire
Increased compliance
Don’t have passive expiration
No natural recoil
Difficult to fill with air
Decreased compliance
Pulmonary fibrosis
Formation or development of excess fibrous connective tissue in lungs (stiff lungs)
High levels of elastance, high recoil, easy to exhale
Effort to inspire
What causes pulmonary fibrosis
Inhalation of pollutants, infections, idiopathic
What is emphysema
Proteolytic enzymes secreted by leukocytes attack alveolar tissue
Alveoli merge; loss of capillaries and surface area
What happens to lungs from emphysema
- loss of lung recoil
- airway resistance
- inhale easy, force expire out
- increased compliance loss of elastance
Obstructive
In healthy lung what is not cause of compliance and lung recoil
Elasticity of pulmonary cells and Extracellular matrix
