What is the primary function of the respiratory system?
Absorption of O2 and excretion of CO2
What is the secondary function of the respiratory system?
Filters both inhaled contaminants and small clots or chemicals from blood
What is internal respiration?
Gas exchange between tissues and systemic capillary blood "into lungs"
What is external respiration?
gas exchange between lungs and atmosphere
What are the stages in the development of respiartory therapy?
- Embryonic period - conception - week 6
- Psuedoglandular period - week 7-16
- Canalicular period - week 17-26
- Saccular and alveolar period - week 27 - roughly 25 years of age
When does respiratory development begin in the embryonic period?
On or about the 22nd day after fertilization
What happens in respiratory development at the 5th week of development?
Tracheal bud continues to develop and bifurcates (divide into to parts) into Left and Right primary bronchial buds
What happens during the 6th week of respiratory development?
Gestation, lungs and airway development has the appearnce of a glandular structure hence the name, Pseudoglandular stage
What happens at week 10 of respiratory development?
Growth and branching of the tracheobronchial (TB) tree and pulmonary vasculatre continue with formation of terminal and respiratory bronchioles
What 2 bronchioles develop during the 10th week and what do they do?
- Terminal Bronchiole - conducts airways that do not participate in gas exchange with blood
- Respiratory Bronchiole - are capable of gas exchange
What appears during 16-17 week of development of the respiratory?
Acini appear, they are the basic gas exchanging unit of the lung
What happens at week 20-24 of respiratory development?
- Fourth Phase, terminal saccular stage
- Type 1 and 2 pneumocytes begin to appear (epitheial cells that cover the gas exchange surface)
What happens at week 32 until 601 years of age in respiratory development?
- Mature alveoli occur
- Alveolar period
What happens to alveoli when child is around 10 years old?
Type 1 and 2 pneumocytes covering the pulmonary capillaries that have formed just below the basement membrane
What is surfactant?
- It keeps lungs open giving child ability to breathe
- Reduces surface tension of fluid in the lungs and helps alveoli more stable
- Made from Type 2 pneumocytes
What does surfactant consist of?
- Phospholipids, some protein and a trace of carbohydrates
- Type 2 pneumocytes
What is the umbilical cord consits of?
- 1 umbilical vein
- 2 arteries
What is the purpose of fetal lung fluid?
Keeps the lung inflated and is constantly being produced
What expels fetal lung fluid during birth?
1/3 of the fetal lung fluid is expelled through the mouth by Thoracic compression and the rest is absorbed byt he lymphatic system
Do maternal and fetal blood ever touch? What exchanges does it permit?
- They come in close contact but remain sepearted by an emryonic membrane
- Exchange of O2, CO2, water, ions, various metabolic molecules and hormones
What are the 3 important bypass pathways in fetal circulation?
- Ductus Venosus
- Ductus Arteriousus
- Foramen Ovale
2/3 of blood flow go through what and bypass the livers circulation and flows to the inferior vena cava?
Approx 50% of this blood is shunted from the Right atrium into the Left atrium through?
The Ductus arteriosus stays open because?
- Decreased O2 (hypoxia)
- Prostaglandins from the mother
90% of blood flow entering pulmonary artery takes the path of least resistance by shunting through the?
Ductus Arteriosus, only 10% actually flows through the lungs.
During postnatal lung development, infants breathe through their?
The ______ is much rounder and the ________ is much larger relative to the size of the oral cavity.
Greater relative weight in the head can cause what in infants?
acute flexion of the cervical spine
The larynx is located where in an infant?
- Lies higher in the neck than in later years, with the glottis located between C3 and C4
- It is also more funnel shaped that that of an adult
What is the narrowest region of the upper airway?
What makes newborns and infants more susceptible to Upper Respiratory infections?
- Bigger head
- narrower cricoid cartilage (funnel shaped)
- Bigger tongue
If the chest was split in half, what would the left or right be called?
Left or Right Hemithorax
If hemithorax was split in half what would that be called?
How long is a normal newborn trachea?
5-6 cm and is shorter and narrower
What do phrenic fibers do?
Form to carry motor signals to diaphragm and intercostal muscles
The phrenic nerve is connected to what on the spine?
C3, C4 and C5 of spine
What are the primary muscles of respiration?
Diaphragm and intercostal muscles
What do parasympathetics do?
Mucous gland to cause mucous production
What do sympathetics do?
Blood vessels to cause vasoconstriction
What is the 10th carnial nerve that carries motor and sensory signals of the parasympathetic system?
During chest wall development an infants thoracic wall...?
Is more compliant and their muscles are less developed then those of an adult and provide little structure and support
What is more box-like and ribs being horizontally elevated?
Infants thoracic cage
By age 10, ______ has the configuration of an adult. Ossification of ribs and sternum is complete by the age of 25 and with msucle stiffens the chest wall
Ribs and sternum
What is the chest wall made up of?
- skeletal muscles and bony muscles form over portion of the wall
What is the function of chest wall?
- Cone shaped cavity contains vital organs
- To protect organs
- Ability to change shapes, facilitates breathing
What is the parietal pleura lined with?
- Lining of the chest wall
- inner layer is lined with serious membrane
What covers the lungs?
What is seperated by thin fluid layer?
Why is pleural space needed?
To decrease friction/lubricate between parietal and visceral pleura
How many pairs of ribs do we have? which ones are true? which ones are false?
- true ribs = first 7, connect directly to sternum
- false ribs = 8-10
- floating ribs = 11 and 12
What muscles do we use for respiration?
Active during resting breathing, 75% of the work is performed by diaphragm other 25% is by intercostal muscles
What accessory muscles do we use for inspiration?
scalene and sternocleidomastoids
Scalene muscles lifts what while inspiration?
Upper chest area and clavicle
What muscles are used during expiration?
abdominal muscles and ribs being pulled down by internal intercostal muscles
What is the costophrenic angle or diaphragmatic angle?
Where the parietal and pleura departs chest wall to diaphragm
How many lobes are in the lungs?
- 2 in the left
- 3 in the right
What are the lobes in the lungs seperated by and what are they called?
- Seperated by fissures
- Oblique fissures are in the bottom of the lobes
- Transverse or horizontal fissure in the top right lobe
The pulmonary venous circulation delivers what TO which atrium?
Oxygenated blood blood tTO the left atrium
Pulmonary arterial circulation delivers what FROM which ventricle?
Deoxygenated blood FROM right ventricle
What is the reason for higher resistance in systemic circulation vs pulmonary respiration?
- Increased pressure = increased resistance
- Systemic circulation needs higher pressure because it travels a much longer distance
How many places can the lungs get O2 from its own tissues?
- Alveoli/inspired gas
- Bronchial circulation from Left ventricle (oxygenated blood)
What is the function of the lungs?
Lung elasticity results from alveolar surface tension and elastic connective tissue
What does the Hering-Breuer reflex do?
- Negative feedback
- Stretch receptors function to limit further stretch
- Probably inactive during further breathing
Dust and foreign body in lungs are expelled through what? or how?
- Irritant reflexes
- Cough, sneeze, bronchospasms, hyperpnea, closing of glottis, vasovagal reaction (bradycardia), irritant reflexes
What are some components of the Upper Respiratory Tract? URT
- Nasal cavities or nares
- Oral cavity
What is the nasal cavity for?
- Humidifies air
- Filters air
- Warms air
- Gas exchange
What are your four sets of sinues?
What is another name for the adam's apple?
What is the space between vocal cord?
What is the function of sinuses?
- Reduce weight of head
- Strengthen skull
- Modify the voide during phonation
What is the ideal breathing position for unconscious PT for intubation?
- "Sniff position"
- Neck extended back pulling jaw down
What gland secretes along the airway?
What are the functions of mucus?
- Protects from irritants
- Protects from toxic particles
- Prevents fluid/water loss
What is the only purpose of conducting airwaysin the LRT?
Convey gas from URT to area of gas exchange (lung parenchyma)
What is the wave like or movement of cilia called?
What mainstream bifurcates at carina?
the Right bronchus is at what angle or degree? why is it easier for foerign aspirate to get into?
20-30 degree angle
What is the degree or angle of left bronchus?
How many segments do the lungs have?
10 segments each
What is the measure of anatomic deadspace?
~2 ml/kg of lean body weight, typically 150ml
What are the 3 layers of the airway wall?
What are the 2 functions of respiratory bronchioles?
- Conduct gas deeper in respiratory zone
- Participate in gas exchange
What is the airway on terminal bronchi called?
Conductivity airway = its for movement not respiration
Terminal bronchi to alveoli is called?
Acinus = functional of the lung
What can impair cilliary movement?
- Drying of mucus
The process of gas exchange is called?
Diffusion (high pressure to low pressure)
What part of the heart gives blood supply to lungs?
Bronchial circulation and pulmonary circulation
If the costrophrenic angle can not be seen in a chest x-ray, what does that mean?
Pleural effusion = fluid in the pleural space