week 3 lower respiratory Flashcards
(30 cards)
Lower respiratory tract
Trachea
- Descends: larynx through neck into
mediastinum - Divides in thorax into two main
(primary) _________ - 16-20 c-shaped rings of ________
cartilage joined by fibroelastic
connective tissue - Flexible for bending
- Stays open despite pressure changes
during breathing
bronchi
hyaline
Trachea
- ________ muscle can decrease diameter of trachea
- Esophagus can expand when food swallowed
- Food can be forcibly expelled
- Wall of trachea has layers common to
many tubular organs – filters, warms
and moistens incoming air
Trachealis
Carina
- Ridge on internal aspect of last tracheal cartilage
- Point where trachea branches
- Mucosa highly sensitive to irritants: cough reflex
has a mucosa highly sensitive to irritants that can help with the COUGH REFLEX
also this region is the ridge on internal aspect of last tracheal cartilage
CARINA
Main stem bronchi
* Right main stem bronchus is wider and
shorter than the left
* This in addition to the angulation of
the bronchus predisposes the _____
lung for aspiration of foreign objects
Right
Lower respiratory tract
Main=primary bronchi divide into secondary bronchi, each supplies one lobe
* __on the right
* __on the left
Lobar bronchi branch into segmental bronchi
* Continues dividing: about 23 times
Tubes smaller than 1 mm called bronchioles
Smallest are the terminal bronchioles
* less the 0.5 mm diameter
3 on the R
2 on the L
Lower respiratory tract
Tissue changes as becomes smaller
* Cartilage plates, not rings, then disappears
- Pseudostratified columnar → simple columnar → simple cuboidal without mucus or cilia
- Smooth muscle important: sympathetic relaxation “broncho________”, parasympathetic constriction “broncho________ ”
bronchodilation
bronchoconstriction
Respiratory zone
- End-point of respiratory tree
- Structures that contain air-exchange
chambers are called _______ - Respiratory bronchioles lead into alveolar
ducts: walls consist of alveoli - Ducts lead into terminal clusters called
alveolar _____ – are microscopic chambers - There are ~400 million alveoli
alveoli
sac
- Movement of air in and out of lungs
- Continuous replacement of gases in alveoli (air
sacs)
Pulmonary ventilation
- Gas exchange between blood and air at alveoli
- O 2 (oxygen) in air diffuses into blood
- CO 2 (carbon dioxide) in blood diffuses into air
External respiration
- Between the lungs and the cells of the body
- Performed by the cardiovascular system
- Red blood cells are the transportation
Transport of respiratory gases
Internal respiration
Internal respiration
- Gas exchange in capillaries between blood and tissue cells
- O 2 in blood diffuses into tissues
- CO 2 from tissues diffuses into
blood
Cellular Respiration
Cells will use the O 2 to produce ATP
Gas exchange
* Air filled alveoli account for most of the lung volume
Alveolar wall
* Single layer of squamous epithelial cells 0.5μm (15 X thinner than tissue paper)
* External wall covered by capillary beds
Respiratory membrane: fusion of the basal laminas of
* ________wall
* ________wall
alveolar wall and the capillary wall
air-blood barrier
- This “air-blood barrier” (the respiratory
membrane) is where gas exchange occurs - Oxygen diffuses from air in alveolus to blood in capillary
- Carbon dioxide diffuses from the
blood in the capillary to the alveolus
Surfactant
Surface-active lipoprotein complex
* Detergent-like substance which is secreted in fluid coating alveolar surfaces – it decreases tension
- Type II granular pneumocytes are scattered in alveolar walls
- Without it the walls would ______ ______ during exhalation and the lungs would collapse
- Premature infants– problem breathing is largely because they lack _______
- Produced at 24-28 weeks
stick together
Surfactant
Lungs and Pleura
Around each lung is a flattened sac of serous membrane called pleura
Parietal pleura – outer layer
Visceral pleura – directly on lung
Pleural cavity - space filled with pleural fluid
Acts as a lubricant to reduce ______ during breathing»_space; lungs cling to wall and are forced to expand and recoil as volume of thoracic cavity changes during breathing
friction
- Paired lungs occupy all thoracic cavity lateral to the mediastinum
- Mediastinum contains (mainly): heart, great blood vessels, trachea, main bronchi, ________
esophagus
Lungs
* Cone-shaped with anterior, lateral and posterior surfaces contacting ribs
- Superior tip is _____, just deep to clavicle
- Concave inferior surface resting on diaphragm is the base
apex
Hilus or (hilum)
* Indentation on medial surface
* Place where blood vessels, bronchi, lymph vessel, and nerves ______ and _____ the lung
“Root” of the lung
* Above structures attaching lung to mediastinum
* Main ones: pulmonary artery and veins and main bronchus
enter and exit
- Right lung: _ lobes
- Upper lobe
- Middle lobe
- Lower lobe
- Left lung: _ lobes
- Upper lobe
- Lower lobe
R lung 3 lobes
L lung 2 lobes
Lungs
Each lobe is made up of bronchopulmonary segments separated by dense connective tissue
* Each segment receives air from an individual segmental (tertiary) bronchus
* Limit spread of ______
Smallest subdivision seen with the naked eye is the lobule
* Hexagonal on surface, size of pencil eraser
* Served by large bronchiole and its branches
* Black carbon is visible on connective tissue separating individual lobules in smokers and city dwellers
infection
Lungs
* Pulmonary arteries bring oxygen-poor
blood to the lungs for oxygenation
* They branch along with the bronchial tree
* The smallest feed into the pulmonary
capillary network around the alveoli
* ________ veins carry oxygenated blood
from the alveoli of the lungs to the heart
pulmonary
Lungs
Blood supply
Lungs get their own blood supply from bronchial
arteries and veins
Innervation
Pulmonary plexus contains sympathetic,
parasympathetic and visceral sensory fibers to
each lung
Lungs
Blood supply
Lungs get their own blood supply from bronchial
arteries and veins
Innervation
Pulmonary plexus contains sympathetic,
parasympathetic and visceral sensory fibers to
each lung
