Lec 18- Respiratory system Flashcards
Ventillation
Moves air in and out of lungs for gas exchange with blood.
Gas exchange
between blood and tissues. Passive. O2 in and CO2 out
O2 utilizaton
cellular respiration
External respiration
Air that moves in and out of lungs
Internal respiration
Gas exchange between blood and tissues and )2 use by tissues.
Diaphragm
Skeletal muscle below the lungs that aid in ventilation.
Thoracic cavity
chest cavity. Lungs take up the most space.
Peritoneal cavity
The peritoneal cavity is a true space between the parietal peritoneum (the peritoneum that surrounds the abdominal wall) and visceral peritoneum (the peritoneum that surrounds the internal organs).
Intrapleural space
Between the parietal and visceral pleura is the intrapleural space, or pleural cavity. This contains a small amount of serous fluid which establishes adhesion between the layers and allows smooth movement between the lung and chest wall, and between individual lobes of the lungs.
Visceral pleura
covering lungs
Parietal pleura
lining thoracic cavity walls
Pharynx
throat. Serves as the common passageway for both respiratory and the digestive system.
Larynx
voice box, located at entrance to trachea
Esophagus
tube in which food passes through to get to the stomach.
Type I alveolar cells
Make up the alveolar walls.
Type II alveolar cells
secrete pulmonary surfactant.
Surfactant
Surface acting agents.
Consists of phospholipids secreted by type II alveolar cells.
Lowers surface tension by getting between H2O molecules, reducing their ability to attract each other via hydrogen bonding.
Boyle’s law
P1V1=P2V2
Inspiration
Taking in air from outside
Contraction of diaphragm, external intercostal muscels.
Expiration
expelling air from outside
Contraction of internal intercostal muscles and abs for forced air expulsion.
External intercoastal muscles
Contraction needed for inspiration.
Internal intercoatal muscles
Contraction needed for forced expiration.
Scalenes
Contraction needed for forced inspiration.
Sternocleidomastoids
Contraction needed for forced inspiration.
Intrapulmonary
Inside the lung.
Pressure during inspiration -3 mmHg.
Pressure during expiration +3 mmHg
Transpulmonary
Positive transpulmonary pressure (intrapulmonary - intrapleural pressure) keeps lungs inflated.
Transmural
net outward pressure differential pushes out on the lungs, stretching or distending them.
Compliance
The distensibility of a hallow, elastic structure, such as a blood vessel or the lungs; a measure of how easily the muscle can be stretched.
Pneumothorax
The abnormal condition of air entering the pleural cavity.
Spirometry
Detects changes in lung volume.
Consists of an air-filled drum floating in a water filled chamber.
Anatomical dead space
No gas exchange occurs.
Part that remains in the conducting airways.
Tidal volume
Air moved in and out of the lungs during relaxed breathing.
Avg = 500 mL
Inspiratory reserve volumes
The extra volume of air that can be actively inspired over and above the typical resting tidal volume.
Avg = 3000 mL
Expiratory reserve volumes
The extra volume of air that can be actively expired by maximally contracting the expiratory muscles beyond the tidal volume.
Avg = 1000mL
Residual volume
Air left in the lungs after a maximum exhalation.
Avg = 1200 mL
Total lung capacity
The maximum volume of air that the lungs can hold.
Avg = 5700 mL
Vital capacity
The maximum volume of air that can be moved out during a single breath following a maximal inspiration.
Avg = 4500 mL
Restrictive pulmonary disease
Decreased lung compliance. reduced inspiratory volume, in other words, there is a reduced vital capacity but with normal forced vital capacity.
E.g. pulmonary fibrosis, respiratory distress syndrome.
Obstructive pulmonary disease
Increased airway resistance - can be related to loss of elasticity - reduced airway flow (reduced diameter), in other words, there is a normal vital capacity but expiration is slowed down.
E.g. emphysema, asthma, pulmonary edema. Collectively, these are referred to as COPD
FEV 1 - forced expiratory volume
This test measure the rate of expiration.
Is at about 80% = Patient has restrictive pulmonary disease.
If less than 80% = patient has obstructive type pulmonary disease.
Dyspnea
shortness of breath;most common symptom of COPD
Asthma
A condition in which a person’s airways become inflamed, narrow and swell, and produce extra mucus, which makes it difficult to breathe.
Trachea
windpipe; through which air is conducted to the lungs.
Bronchus
Branch off the trachea to each lung.
Bronchioles
Branch off bronchus
Terminal bronchioles
Terminal bronchioles. The terminal bronchiole is the most distal segment of the conducting zone. It branches off the lesser bronchioles. Each of the terminal bronchioles divides to form respiratory bronchioles which contain a small number of alveoli.
Respiratory bronchioles
The respiratory bronchioles are the narrowest airways of the lungs, 0.5 mm across. The bronchi divide many times before evolving into the bronchioles. The respiratory bronchioles deliver air to the exchange surfaces of the lungs. They are interrupted by alveoli which are thin walled evaginations.
Alveolar sacs
Site where gas exchange occurs
Conducting zone
humidifies and warms inspired air.
Surface tension
Lungs secrete and absorb fluid, normally leaving a thin film of fluid on alveolar surface.
This film causes ST because H2O molecules are attracted to other H2O molecules.
Fibrosis
Fibrosis is the formation of excess fibrous connective tissue in an organ or tissue in a reparative or reactive process. This can be a reactive, benign, or pathological state. In response to injury, this is called scarring, and if fibrosis arises from a single cell line, this is called a fibroma.
Elasticity
Is tendency to return to initial size after distension.
Due to high content of elastin proteins.
Elastic tension increases during inspiration and is reduced by recoil during expiration.
Cystic fibrosis
defect in the CFTR gene. Messes with chloride channels.
Law of Laplace
states that pressure in alveolus is directly proportional to ST and inversely to radius alveloi.
Pressure in smaller alveoli would be greater than in larger alveoli, if ST were the same in both.
ARDS - respiratory distress syndrome
In adults, spetic shock may cause acute respiratory distress syndrome (ARDS) which decreases compliance and surfactant secretion.
RDS - respiratory distress symptom
Premies are often born with immature surfactant system Have trouble inflating lungs.
Emphysema
Emphysema is a type of COPD involving damage to the air sacs (alveoli) in the lungs. As a result, your body does not get the oxygen it needs. Emphysema makes it hard to catch your breath. You may also have a chronic cough and have trouble breathing during exercise. The most common cause is cigarette smoking.
COPD - chronic obstructive pulmonary disease
Emphysema, asthma, pulmonary edema. Increased airway resistance.
Atelectasis
Atelectasis is collapse of lung tissue with loss of volume.
