respiratory system Flashcards
Know the difference between external and internal respiration
External respiration -
exchange of gases with the external environment, and occurs in the alveoli of the lungs.
Internal respiration -
exchange of gases with the internal environment, and occurs in the tissues.
Be able to describe the parts of the respiratory system in the conducting zone vs. the respiratory zone
respiratory zone
where gas exchange occurs
capillaries, alveoli, pulmonary artery and vein
conducting zone
organs and structures not directly involved in gas exchange.
The external nose
- Root, Bridge (Dorsum nasi = length of the nose), Apex, Nostrils/ alae (singular = ala, plural = nares), or nostril opening, Philtrum
- Septal cartilage, alar cartilage.
nasal cavity, upper airway
- nares-> nasal cavity, left and right sections by nasal septum.
- - three bony projections, superior, middle, and inferior nasal conchae.
conchae and meatuses
- Conchae, aka turbinates, increase surface area of nasal cavity and disrupt flow of air as it enters the nose, causing air to bounce along epithelium, where it is cleaned and warmed.
- also prevent dehydration of nasal epithelium by trapping water during exhalation.
nasal cavity
- hard and soft palate.
- nasal cavities -> internal nares -> pharynx.
- mucous membranes: seb. glands and hair follicles
paranasal sinuses
- warm and humidify incoming air. lined with mucosa.
- frontal sinus, maxillary sinus, sphenoidal sinus, and ethmoidal sinus. sinuses produce mucus and lighten weight of the skull.
Study slide 14 being able to label the anatomy of the upper respiratory system
review!
Know the features of the upper respiratory epithelium - goblet cells, cilia
The epithelium contains goblet cells, specialized, columnar epithelial cells that produce mucus to trap debris.
The cilia of the respiratory epithelium help remove the mucus and debris from the
nasal cavity
Serous and mucus-producing cells also secrete the lysozyme enzyme and proteins called defensins, which have antibacterial properties.
Know the features of the upper respiratory epithelium - pharynx, uvula, larynx, epiglottis and vocal cords, trachea, bronchial tree
pharynx has three major regions: nasopharynx, oropharynx, and laryngopharynx
- nasopharynx: airway.
- pharyngeal tonsils, uvula, auditory (Eustachian) tubes
- oropharynx: passage for both air and food.
- fauces, palatine tonsil, lingual tonsil
- laryngopharynx regulate volume of air that enters and leaves lungs
- thyroid cartilage (anterior), epiglottis (superior), cricoid cartilage (inferior), the arytenoids, corniculates, and cuneiforms—attach to
epiglottis and vocal cords. glottis: vestibular folds, true vocal cords
The trachea (windpipe).
- 16 to 20 stacked, C-shaped pieces of hyaline cartilage
- trachealis muscle & elastic connective tissue together form fibroelastic membrane,
- trachea branches into right and left primary bronchi at the carina, which induces violent coughing if a foreign body, such as food, is present.
- The primary bronchi enter the lungs at the hilum, a concave region where blood vessels, lymphatic vessels, and nerves also enter the lungs.
bronchial tree (respiratory tree): multiple-branched bronchi. provide a passageway for air to move into and out of each lung. mucous membrane traps debris and pathogens.
- Primary bronchi -> secondary bronchi -> tertiary bronchi -> bronchiole -> terminal bronchioles (no cartilage here), which lead to structures of gas exchange.
Know the features, functions and anatomy of the respiratory zone
thin-walled structures that allow gas exchange: inhaled oxygen (O2) to diffuse into the lung capillaries in exchange for carbon dioxide (CO2).
The four structures that make up the respiratory zone are:
* the respiratory bronchioles
* the alveolar ducts
* the alveolar sacs
* the alveoli
terminal bronchioles -> respiratory bronchiole, the smallest type of bronchiole -> alveolar duct -> cluster of alveoli.
What is the respiratory membrane?
The simple squamous epithelium formed by type I alveolar cells is attached to a
thin, elastic basement membrane. This epithelium is extremely thin and borders
the endothelial membrane of capillaries. Taken together, the alveoli and capillary membranes form a respiratory membrane
- approx 0.5 mm thick.
- allows gases to cross by simple diffusion, allowing oxygen to be picked up by the blood for transport and CO2 to be released into the air of the alveoli.
Understand the anatomy of the alveolus paying attention to the types of cells and why they are important
alveolar duct -> cluster of alveoli (grape like sacs) -> alveoli connected by alveolar pores
Anatomy of the Alveolus
The alveolar wall = three major cell types:
- type I alveolar cells
- type II alveolar cells
- alveolar macrophages.
Type I alveolar cell: squamous epithelial cell of the alveoli, constitute up to 97 percent of the alveolar surface area. These cells are about 25 nm thick and are highly permeable to gases.
Type II alveolar cell:
interspersed among the type I cells and secretes pulmonary surfactant, a substance composed of phospholipids and proteins that reduces the surface tension of the alveoli.
Alveolar macrophage: phagocytic cell of the immune system that removes debris and pathogens that have reached the alveoli
Know about the features, anatomy and blood supply of the lungs
Features
- pyramid-shaped, paired organs
- trachea -> right, left bronchi -> pleurae, attached to mediastinum -> diaphragm
- right lung is shorter and wider than left lung, and the left lung occupies a smaller volume than the right.
- cardiac notch is an indentation on the surface
of the left lung, and it allows space for the heart.
- apex of the lung: superior region
- base is near the diaphragm.
- costal surface borders the ribs
- mediastinal surface faces the midline.
Each lung composed of -> lobes, fissures separate lobes from each other -> right lung three
lobes: superior, middle,
inferior -> left lung two lobes: superior and inferior.
The major fx of the lungs: to perform gas exchange, requires blood frm pulmonary circulation.
deoxygenated blood travels to the lungs where erythrocytes, pick up oxygen to be transported to tissues throughout body.
pulmonary trunk -> pulmonary artery carries deoxygenated, arterial blood -> pulmonary capillary network -> capillary wall, alveolar wall (respiratory membrane) -> alveoli, blood is oxygenated -> multiple pulmonary veins -> hilum, exit lungs
What is the hilum of the lung and be able to identify the structures that enter the lungs at the hilum?
The hilum (root) is a depressed surface at the center of the medial surface of the lung.
It is the point at which various structures enter and exit the lung.
Both left and right
hilum contain a pulmonary artery, pulmonary veins (superior and inferior), and
bronchial arteries.
left hilum, there is principal bronchus,
in the right hilum, there are two bronchi.
How does the autonomic nervous system affect bronchial function? Sympathetic vs. parasympathetic
Dilation and constriction of the airway are achieved through nervous control by the
parasympathetic and sympathetic nervous systems.
parasympathetic system
causes bronchoconstriction
sympathetic system
stimulates bronchodilation
Reflexes (coughing, ability of the lungs to regulate oxygen and carbon dioxide levels), also result from this autonomic
nervous system control.
Know about the features and anatomy of the pleura
The pleura: (plural = pleurae) serous membrane that surrounds lung.
The right and left pleurae separated by the mediastinum.
The pleurae: two layers.
- visceral pleura: superficial to the lungs, extends into and lines lung fissures
- parietal pleura: outer layer that connects to the thoracic wall, the mediastinum, and the diaphragm. The visceral and parietal pleurae connect
to each other at the hilum.
- pleural cavity is the space between visceral and parietal layers.
The pleurae perform two major functions:
- produce pleural fluid and
- - create cavities that separate the major organs.
Pleural fluid is secreted by mesothelial cells from both pleural layers and acts to
lubricate their surfaces.
Understand the anatomical and physiological features of breathing
Pulmonary ventilation
act of breathing, movement of
air into and out of the lungs. dependent on the air pressure of the atmosphere and within the lungs. air flows down a
pressure gradient
- Inspiration causes air to enter the lungs: diaphragm and external intercostal muscles.
- expiration causes air to leave the lungs.
A respiratory cycle is one
sequence of inspiration and expiration.
Inspiration
- diaphragm contracts, moves inferiorly toward abdominal
cavity, larger thoracic cavity
- Contraction of the external intercostal muscles moves the ribs upward and outward
- adhesive force of the pleural fluid, forces the lungs to stretch and expand as well.
- decrease in intra-alveolar pressure, creating a pressure lower than atmospheric pressure. As a result, a pressure
gradient is created that drives air into the lungs.
Expiration
- passive, energy is not required
- elasticity of lung tissue causes lung to recoil, as diaphragm and intercostal muscles relax
- thoracic cavity & lungs decrease in volume, causing
increase in intrapulmonary pressure.
Types of Breathing
- Quiet breathing, eupnea, occurs at rest. diaphragm and external intercostals must contract.
- Diaphragmatic breathing, a deep breath, diaphragm contract
- shallow, or costal breathing, contraction of the intercostal
muscles
- Forced breathing, hyperpnea, exercise or actions that require active breathing.
accessory muscles that
also contract: muscles of the neck (scalenes), during forced
inspiration or muscles of the abdomen (obliques), during forced expiration
Understand the 4 main types of respiratory volumes
Respiratory Volume
various volumes of air moved by or associated with the lungs at a given point in the respiratory cycle.
There are four major types of
respiratory volumes: tidal, residual, inspiratory reserve, and expiratory reserve.
- Tidal volume (TV) amount of air that normally enters lungs during quiet breathing,
which is about 500 milliliters.
- Expiratory reserve volume (ERV) amount of air you can forcefully exhale past a normal tidal expiration, up to 1200 ml
- Inspiratory reserve volume (IRV) produced by a deep inhalation, past a tidal inspiration. extra volume that can be brought into lungs during a forced inspiration
- Residual volume (RV) air left in the lungs if you exhale as much air as possible. makes breathing easier by preventing the alveoli from collapsing.
Understand the concept of dead space
Dead Space
Anatomical dead space, which is air that is present in the airway that never reaches
the alveoli and therefore never participates in gas exchange. Found in conducting
airways from the nose or mouth down to the level of the terminal bronchioles, and is
about 150 ml on the average in humans. The anatomic dead space fills with inspired air at
the end of each inspiration, but this air is exhaled unchanged
Has 3 advantages: warming, filtration, humidification
Alveolar dead space involves air found within alveoli that are unable to function, such as
those affected by disease or abnormal blood flow.
Total dead space is the anatomical dead space and alveolar dead space together, and
represents all of the air in the respiratory system that is not being used in the gas exchange
process.
