TP7 Respiratory System Flashcards
Describe the functions of the respiratory system (7 pts)
- Gas Exchange!! - O2 inspired, CO2 expired
- Temp regulation
- pH balance
- Elimination of water
- Removal of other wastes
- Phonation (speaking)
- Olfaction (nasal cavity)
List the components of the upper respiratory tract (5 pts)
- Nostrils
2.Nasal cavity - Pharynx
- Larynx (voice box)
- Trachea
List the components of the lower respiratory tract (2 pts)
- Trachea
- Lungs
Describe the Nares/Nostrils
- External openings of the airways
- In most species:
- Is soft, pliable and easily dilated
- Supported by cartilage - In pigs:
- Rigid nostrils for digging
- Contain bone
Describe the nasal cavity
- Separated by hard and soft palates
- Palate is divided into bony hard palate rostrally and fleshy soft palate caudally
- Divided into left and right by nasal septum
- Moisten and warms air entering lungs
Describe the location and function of the olfactory nerve
- Sense of smell originates from sensory ending of olfactory nerve
- Found in caudal area of the nasal cavity on conchal extensions of the bones in the front of the cranium
Name the three major conchae
- Dorsal conchae
- Ventral conchae
- Ethmoidal conchae
Describe the structure and function of nasal conchae
- Cartilaginous/slightly ossified scrolls
- Make inspired air more turbulent
- Increase S.A. in nasal cavity
- Airspace in nasal cavity partitioned by conchae into nasal meatuses
Describe the function and location of the pharynx
- Located at the back of the throat
- common passage for food and air
- Soft palate separates entrance of mouth and nasal cavity
Describe the structure and function of Paranasal sinuses
- Air filled spaces within skull bones that connect with the nasal cavity via narrow openings
- Prone to blockage if mucosa is inflamed or thickened
- Each sinus located below the bone of the same name in the skull
Name the common paranasal sinuses in all farm animals
- Maxillary sinus
- Frontal sinus
- Palatine sinus
- Sphenoid sinus
Describe the structure and location of the Pharynx
- Common passage for food and air
- Soft palate separates the entrance of the mouth and nasal passages
- Located at the back of the throat
Describe the structure and location of the Larynx
- Connects between pharynx and trachea
- Made up of five interconnected cartilages
- Epiglottis
- Thyroid
- Arytenoid
- Cricoid
- Allows only gases to lower respiratory tract
Describe the structure of the epiglottis
- Ensures only gases can pass into deeper regions of the respiratory tract
- epiglottis covers laryngeal opening when food is swallowed
List the parts of the Lower Respiratory Tract
- Trachea
- Lobes
- Bronchi: branch into secondary and tertiary bronchi in lungs
- Bronchioles
- Alveoli: Increases S.A. available for gaseous exchange
Describe the Trachea
- Incomplete cartilage rings connected dorsally by a muscle
- Bifurcates to become two bronchi
- Mucous membrane lining ciliated
- Mucociliary transport system
Describe the bronchi
- Incomplete cartilage rings
- Smooth muscles in walls - contraction = constricted airways
- Primary bronchi divides, forming secondary bronchi which further divide into tertiary bronchi
Describe bronchioles
- Tertiary bronchus branches to form bronchioles
- No supportive cartilage
Describe the role of terminal and respiratory bronchioles
Terminal bronchioles marks the end of the conducting zone and the respiratory bronchioles marks the beginning of the respiratory zone
Describe the roles of the alveoli
- Increase S.A. available for gas exchange between inspired air and blood
- Blood capillaries close to alveoli wall - allows gas exchange to take place
List and describe the two types of alveolar epithelial cells
- Type I alveolar epithelial cells: exchange gases
- Type II alveolar cells: secretes surfactant to reduce surface tension
Describe respiratory membrane
- Close association of capillaries to alveoli
Describe the Pleura
- Serous membrane covering lungs and inside thorax
- Facilitates movement of lung during breathing
List the two layers of the pleura
- Parietal pleura: pleural sac attached to the wall
- Visceral pleura: pleural sac attached to the lung
- space between layers is the interpleural space filled with fluid
Describe the structure of the Lungs
- Divided into left and right
- Each lung divided into lobes by fissures
- Soft, spongy texture
- Float in water (foetal lungs dont)
List the sections of the right lung
- Cranial
- Middle
- Caudal
- Accessory
List the sections of the left lung
- Cranial
- Caudal
Describe the structure of the diaphragm
- Musculotendinous division between thoracic and abdominal cavities
- Dome shaped
List the parts of the conducting zone
- Nose
- Nasal cavity
- Pharynx
- Larynx
- Trachea
- Bronchi
- Bronchioles
- Terminal bronchioles
List the parts of the respiratory zone
- Respiratory bronchioles
- Alveolar ducts
- Alveoli
Outline the functions of the conducting zone
- Passages for air to enter respiratory zone
- air warmed and humidified
- immune protection
- goblet cells secrete mucous
- ciliated cells move trapped particles in mucous out of lungs
Outline the functions of the respiratory zone
- Increase S.A.
- Decrease thickness of epithelial wall
- No cilia or goblet cells
Describe pulmonary ventilation
Movement of air into and out of lungs
Describe atmospheric pressure (Patm)
- Pressure of outside air
- Normally 760mmHg at sea level
- All other lung pressures expressed relative to atmospheric pressure
Describe Intra-alveolar pressure (Palv)
- Air pressure within alveoli
- At rest, is equivalent to Patm (therefore 0mmHg)
- Varies during phases of ventilation
- Pressure gradient due to difference between Palva and Patm
Describe intrapleural pressure (Pip)
- Pressure inside pleural space - around 4mmHg at rest
- Always less than Palv and always -ve during normal breathing
Describe how a collapsed lung occurs
- Pleural space breaks -> -ve Pip lost = lung recoils and collapses
Describe respiratory pressures
- Air moves down pressure gradient
- Inspiration: pressure in alveoli < atmospheric pressure = air moves in
- Expiration: pressure in alveoli > atmospheric pressure = air moves out
Describe Boyle’s Law
For a given quantity of gas, in a container at a constant temp, the pressure is inversely related to the volume of the container.
Therefore:
- Decrease vol = increase pressure
- Increase vol = decrease pressure
Describe Inspiration
- Active process - requires energy
- Enlargement of thorax and lungs
- Diaphragm contracts and is pulled down and intercoastal muscles contract
= CHEST ENLARGEMENT
Describe Expiration
- Passive process
- Decrease in size of thorax and lungs
- Relaxation of diaphragm and intercoastal muscles
= CHEST VOL DECREASES
Describe the gas exchange between blood and tissues
- Follows pressure gradient
- PO2 in blood > PO2 in tissues = O2 diffuses from blood into peripheral tissues
- PCO2 in tissues > PCO2 in blood = CO2 moves out of tissues into blood
Where does Oxygen transport occur
In blood in alveolar capillaries
Write the equation for carbon dioxide transport
CO2 + H20 <–> H2CO3 <–> H+ + HCO3-
Describe carbon dioxide transport in tissues
- Bicarbonate ions form in RBC with the help of the enzyme, carbonic anhydrase
- CO2 travels primarily as bicarbonate ions in the bloodstream
Describe carbon dioxide transport in the lungs
Once it reaches the lungs, CO2 diffuses down pressure gradient from blood in pulmonary capillaries to the alveoli for exhalation
- Causes bicarbonate and hydrogen ions in RBC’s to combine, forming carbonic acid, which is converted into CO2 and H2O
- Hydration reaction drives to the left!
How are lung volumes and capacities measured?
A technique called spirometry
Describe Tidal volume (VT)
Volume of air that moves into and out of lungs during a single, unforced breath
Describe Inspiratory reserve volume (IRV)
Max vol of air that can be inspired from the end of a normal inspiration
Describe Expiratory Reserve Volume (ERV)
Max vol of air that can be expired from the end of a normal expiration
Describe Residual Volume (RV)
Volume of air remaining in lungs after max expiration due to -ve intrapleural pressure
Describe Inspiratory capacity (IC)
Max vol of air that can be inspired at the end of a resting expiration
IC = VT + IRV
Describe Vital capacity (VC)
Max vol air that can be expired following max inspiration
VC = VT + IRV + ERV
Describe Total Lung Capacity
Vol of air in lungs at the end of max inspiration
TCL = VT + IRV + ERV + RV
How is respiration controlled?
- Controlled by the Respiratory control center in the medulla oblongata and pons of the brain stem
- Chemoreceptors detect chemical signals
Describe the following Pathological conditions:
- Hypoxia/Hyperoxia: lower/higher O2 than normal in blood
- Hypocapnia/Hypercapnia: lower/higher CO2 than normal in blood
- Emphysema: air sacs in lungs damaged and enlarged
- Pneumonia: lung inflammation due to bacterial/viral infection
- Anorexia: No oxygen
- Bronchitis: Infection/inflammation of bronchi
List the differences between avian and mammalian respiratory systems (6 pts)
- No blind ended alveoli
- Has conducting passages that eventually become tiny one-way passages, parabronchi
- Lungs aren’t divided into lobes
- No diaphragm
- Air capillaries open off walls of each parabronchus
- Larger S.A.:V ratio in avian
Describe the features of fish respiratory systems
- Ventilation unidirectional
- Water enters buccal cavity through the mouth, passes over row of gills and exits
Describe the structure of fish respiratory system (4 pts)
- Gill opening covered by operculum
- Gills consist of bony or cartilaginous stiffened arches - anchor pairs of gill filaments
- Lamellae are site of gas exchange
- Dense capillary beds
Describe the respiratory system of turtles
- Rib cage fused to shell
- Aquatic turtles: mucous membranes lining inside of mouth capable of extracting O2 from water
Describe the respiratory system of snakes and lizards
- Use intercoastal muscles to ventilate lungs
- Some sea snakes use skin of respiration when submerged
- Trachea, bronchi, lungs, air sac
- No diaphragm
Describe the respiratory system of crocodiles
- Connective tissues hepatic septum attached to liver; paired diaphragmaticus muscles
- Muscle anchored to pubic bone - pulls down lungs and expands them
- No diaphragm
