Respiratory System Flashcards
(21 cards)
Respiratory system
Network of organs and tissue that help you breath (oxygen in and carbon dioxide out). Incudes your airways, lungs, blood vessels and the muscles that power your lungs.
Main function:
- Provides extensive area fro gas exchange
- Regulation of blood pH
- Producing speech sounds
- Provides olfactory sensations
- Protection of the respiratory system
Cellular Respiration
Cellular respiration is a series’s of chemical reactions that break down glucose to produce ATP, which may be used as energy to power many reaction throughout the body.
Upper Airway
Nose & nasal passageways
- Primary air passage way
- Consists of bone & cartilage
- Covered by connective tissue & skin
Nasal mucosa
- Filters, cleans, warms & humidifies air
- Prepares air for lower respiratory system
- Detection olfactory stimuli )sensory receptors for olfactory stimuli, smell, are situated in the olfactory epithelium)
- Open into pharynx
Pharynx
- Hollow tube inside the neck that starts behind the nose and ends at the tops of the trachea (windpipe) and oesophagus.
- Common passageway of respiratory and digestive system.
Lower Airways
Larynx - “Voice box”
- Where the vocal cords are found - 9 pieces of cartilage.
- Thyroid cartilage (hyaline cartilage structure that sits in front of the larynx and above the thyroid gland) = Adam’s apple.
- Cricoid cartilage (is the only complete ring of cartilage around the trachea) = landmark for tracheotomy
- When you swallow food, the larynx moves upward and tips the epiglottis over the opening of the trachea.
- Sound produced when outgoing air passes over a pair of vocal cords.
Trachea - “windpipe”
- Extends from larynx to primary bronchi
- Connective tissue and smooth muscle - reinforced with c shaped rings of cartilage that protect trachea and maintains open passage way.
- Numerous cilia cells and goblet cells (produce mucus) - protection against dust/pathogens.
- Divides into left & right primary bronchi
Bronchi
C shaped cartilage rings for support
Right primary bronchus large
- Thus most blockages enter right bronchus.
Wher airways enters lungs primary bronchi and ther branches form bronchial tree
Primary, secondary & tertiary bronchi
The walls contain progressively less amounts of cartilage
As the mount of cartilage decrease the amount of smooth muscle increases
Anatomy of the lungs
Situated in the thorax
Closed compartment
- Bounded at neck
- Diaphragm separated thorax and abdomen
- Spinal column, ribs and sternum - wall
- Wall - also contains lots of connective tissue with elastic properties.
- Intercostal muscles lie between your ribs, attaching them to one another.
Lungs are a Pleural Sac
Pleura
A serous membrane that fold back on itself to form a two layered membranous pleural sac.
Lungs = Two pleural cavities separated by mediastinum
Pleura consists 2 layers
- Parietal pleura (outer) - covers inner surface of thoracic wall
Visceral pleura (inner) - covers the outer surface of the lungs. extending int fissures between lobes.
Lungs
2 lungs - left and right
- Greyish in colour and are spongy in appearance.
- Right - 3 lobes
- Left - 2 lobes
Bronchial tree
- Trachea -> Primary bronchi -> Secondary bronchi -> Tertiary bronchi -> Bronchioles -> Terminal bronchioles -> Respiratory bronchioles -> Alveolar ducts -> alveoli
Alveoli (tiny air sacs)
- Approx. 300 million in adults
- site of gas exchange
Conducting Zone
Consists of nasal cavity through to terminal bronchioles - no alveoli or gas exchange.
Low resistance pathway
Defence
Warm & moistens air
Vocal cords
Respiratory zone
Respiratory Brochioles - connected to individual alveoli
Alveolar ducts
Alveolar sacs
Contains alveoli
Site of gas exchange
Alveoli - Site of gas exchange
Alveolar walls contain capillaries & very small interstitial space - blood separated from air within alveolus by extremely thin barrier (0.2um compared to normal 7um)
Approx. 150 million per lung
Total surface area of alveoli in contact with capillaries - size of tennis court
Alveoli cont.
They exchange CO2 & O2
each alveolus surround by network of capillaries
Gases can dissolve and diffuse between the lungs and blood vessels
Blood that enters the vessel has a high leve of CO2 - from body tissue. Low/little oxygen
CO2 leaves the blood, into the alveoli and into the lungs.
Oxygen from the airl in the lungs then passes through the walls of the alveoli and blood vessels into the blood.
The CO2 is then expelled from the lungs as we exhale.
Pulmonary ventilation - Breathing
Physical movement of air into and out of respiratory tract.
Primary function id to maintain adequate alveolar ventilation.
Ensure continues supply of O2
2 phase ventilation - Inhalation (inspiration) & Exhalation (expiration)
Respiratory cycle - 1 inhalation followed by 1 exhalation
- 10-15 respiratory cycle per minute.
- Normal adult @ rest - approx. 4L fresh air enter lungs/min
- While 5L blood flows through pulmonary capillaries
- Durong heavy exercise - airflow can increase x20 and blood flow x5
Changes in thoracic volume & thus pressure are responsible for ventilatilation.
Boyle’s Law
Pressure of a gas is inversely proportional to its volume
An increas in the volume of container (lungs) decreases pressure of gas - air moves in
Pressure changes result from changes in dimension of chest wall and lungs.
Gas Exchange
Pulmonary ventilation ensures cells supplied with O2 & removes CO2 arriving from bloodstream
Gas exchange occurs between blood & alveolar air across respiratory membrane.
Need to understand
- Partial pressure of gasses involved
- Diffusion of molecules between a gas & liquid
Partial Pressure of Gases
The air we breath is not a single gas
Atmospheric pressure represents combined effect of collision
- Involving EACH type molecule in air - 78.6% collisions involve N2.
Partial pressure of a gas (P)
- Directly proportional to its concentration
- Net diffusion from high -> low partial pressures
- Affected by temperature
Dalton’s Law
Each gas contributes to total pressure in proportion to its relative abundance
Diffusion at Respiratory Membrane
- Substantial difference in partial pressures across respiratory membrane.
- Gas exchange occurs over small distance (on average 0.5um)
- Gases are lipid soluble
- Large surface area
- Coordinated blood flow & airflow
Respiratory Centres of the Brain
Breathing depends on cyclical excitation of respiratory muscles
- Diaphragm and intercostal muscles
Involuntary control centres - medulla oblongata
- Regulation of respiration muscles & control of rep isolation minute volume (volume of gas inhaled or exhaled from a person’s lungs per minute)
- Adjusts frequency and depth pulmonary ventilation.
Voluntary control centres - cerebral cortex
- Affects either - output of respiratory centres in medulla obligate & pons OR motor neurons in spinal cord controlling respiratory muscles.
Respiratory Reflexes
Activities of the respiratory system can be modified by sensory information from multiple sources including:
- Chemoreceptors - most potent stimulus for breathing is pH of bodily fluids.
- Baroreceptors
- Stretch receptors
- Irritating physical/chemical stimuli in both upper & lower respiratory zones.
- Other sensations (e.g. pain), changes in body temp & emotions
Ondine’s Curse
Congenital central hypoventilation syndrome (CCHS) or Primary alveolar hypoventilation
Can be congenial or as a results or sever neurological trauma to the brain stem.
Have to remember to take each breath
Cannot sleep without aid of mechanical respirator.
