Test 1 Flashcards
Explain the mechanics of the diaphragm- in which direction does it move, what impairs its function?
As we take a breath in, the diaphragm contract and moves in a descending position. It shortens or until stopped by abdominal contents.
Then we relaxdiaphragm and it moves basck up to resting position and passively moves air out causing passive expiration
How to the ribs move?
Ribs 1-7 (true ribs)- pump handle, move anterior / post
Ribs 8-10( false ribs) - bucket handle lateral/transverse
Ribs 11,12 free floating
Movement of teh rib cage increases aas go ant and inferiorly
What is the normal breath sequence?
Upper abdominals, lateral coastal, upper chest
What causes limitation of rib expansion?
Bony deformity, decreased joint mobility
Lumbar brace
Quadriplegic or rib fx breathing pattern
Quadriplegic patient with paralysis of inner costals.
Diaphragm contracts, pulls down and a (-) interthoracis pressure is created this time b/c of the lack of stability of the ant rib cage, those ribs are pulled in. Inefficient breathing pattern.
Breathing with a flail chest
We have a section of ribs that have bee fractured & separated from the rest of the rib cage. The diaphragm contracts pulls air in & also b/c of the (-) inter-thoracic pressure the flail section of ribs is also pulled in. Inefficient breathing pattern
How do abdominals help in breathing?
Stabilize the lower rib cage
Provide visceral support
W/o abdominals the diaphragm is flat
Expand T6-L1
Produce force expiration and cough
What are the accessory muscle and how do they work?
Overall they help assist the diaphragm and intercostals
- SCM: helps anterior chest expansion
- Pec Major and minor: lift ant chest, substitute for intercostals
- serratus anterior: post expansion of rib cage
- scalenes: and and sup expansion Ribs 1,2
- erector spinae: post stabilization, extension
- trapezius: with fixed head it lifts clavicles. Stabilizes scapula for serratus ant and pect minor
What do cilia do— what are things that slow their function?
Until terminal bronchioles
- Goblet, serous cells cells secret mucous
- bottom layer- sol 90% water
- top layer- gel traps foreign objects.
The cilia move the secretions until they are coughed out.
Paralyzed by cigarette smoke, alcohol, anethesia up to 20 mins.
Helped by coughings
What is the significance of the pores of Khon?
Allow for ventilation between 2 adjacent alveoli. Which is important b/c if one alveoli gets plugged with mucous it can’t participate in air exchange. B/c of the Pores of khon air can get from one open alveoli into adjacent one
Tell patient to take a deep breath
Parasympathetic system causes what…?
Innervated by vagus nerve
- bronchial constriction
- pulmonary artery dilation
- increased secretions
Sympathetic system causes what…?
- bronchial relaxation
- pulmonary artery constriction
- decreased glandular secretions
What is tidal volume?
The amount of air that we move in and out normally in each breath avg 500 ml/breath
Inspiratory and expiratory reserve volume and residual volume
Inspiratory- on top of the normal inspiration if we breathe in as much as we can 2-3 L.
Expiratory- if we breathe out more at the end of norma tiddal volume ~1L. Beyond that is what we call teh Residual volume ~1L. Air that we cannot mobilize.
Vital capacity and total lung capacity
If we add up all the air that we cann breathe in and out, that forms teh Vital Capacity ~5L. If we add to that the residual volume that we can’t move that gives us total Lung capacity ~6L
Respiratory cycle of dead space
Dead space= 150 mL
When we take in a breath of air, we take the air from that conducting zone which we call teh dead space area. Even though we say the normal tidal volume is 5L of air not all of that participates in air exchange some of it just sits in dead space area
Ventilation vs perfusion?
Ventilation = air exchange Perfusion = blood flow
- Neither are consistent throughout the lungs. In upright poture, ventilation is greater in the apices, perfusion greater in bases. V/Q ratio = 0.8
Blood clot affect of perfusion?
- Increase Physiologic dead space
- even if alveolus has “o” ready to be picked up a blood clot blocks teh blood from picking it up
CLosed alveoli affect on ventilation
Decreased ventilation from closed alveoli
- plugged w/ mucous so no oxygen can come down
Creates a Right to left shunt: normally blood is sent from the right side of the heart to the lungs. If blood goes to alveoli and there is no “O” to pick up, no air exchange takes place. It is as though blood is shunted from right side to left w/o “o”
Elastance vs Compliance
Compliance- how easy it is for lungs to expand
Elastance- how easily lungs return to normal shape
Small resting lung volumes- high compliance: quite easy to expans - room to grow
Large resting lung volumes- low compliance: already full or air - not easy to expans more Ex: COPD
What is teh significance of surfactant?
In the lung we have large alveoli and small ones. Normally if a large alveoli were to expand during inspiration, it would suck all the air out of smaller alveolus. The smaller alveolus would collapse. This does not happen due to production of suurfactant. Surfactant is a mixture of lipoproteins that line themselves up and inc density.
Resistance to air flow and critical closing pressure
Low flow is laminar
High flow is turbulent
As lung volume increases air resistance drops off.
- when the volumes are really low i.e. patient is not taking deep breaths we reach a point called the critical closing pressure where the resistance to flow is do great that the airways collapse.
Oxyhemoglobin dissociation curve
This shows that the greater the Partial pressure of “O” in solution , the greater the diffusion across teh membrane —
The arterial wall consists of…
Adventitia- outer layer: collagen/connective tissue
Media: fibro-muscular, Opens and closes artery
Intime- inner layer: collagen and elastin, permeable to LDL, with age, degenerates and calcifies