Respiratory System Flashcards
(41 cards)
1
Q
What are the two divisions of the respiratory tract?
A
- Upper respiratory tract (nose, pharynx, larynx)
- Lower respiratory tract (trachea, bronchial tree, and lungs)
2
Q
Differentiate between the respiratory membrane and the respiratory mucosa.
A
The respiratory membrane separates the air in the alveoli from the blood in surrounding capillaries.
The respiratory mucosa is covered with mucus and lines the tubes of the respiratory tree.
3
Q
Describe the structure of the respiratory mucosa.
A
- ciliated pseudostratified columnar epithelium (lines most of tract; produces mucus)
- stratified squamous epithelium (lines nostrils, vocal folds, pharynx; protective function)
- simple squamous epithelium (lines alveoli; facilitates gas exchange)
4
Q
Describe the function of respiratory mucosa.
A
- more than 125mL of mucus produced each day forms a “mucous blanket” over much of the respiratory mucosa
- mucus serves as an air purification mechanism by trapping inspired irritants such as dust and pollen
- ciliary escalator (cilia on mucosal cells beat in only one direction, moving mucus upward to pharynx for removal
5
Q
Describe the structure of the nose.
A
- nasal septum separates interior of nose into two cavities
- lined by mucous membrane
- frontal, maxillary, sphenoid and ethmoid sinuses drain into nose
6
Q
Describe the function of the nose.
A
- warms, filters and moistens air
- contains sense organs of smell (olfactory receptors)
7
Q
Describe the structure of the pharynx.
A
- (throat) about 12.5cm long
- divided into nasopharynx, oropharynx, and laryngopharynx
- two nasal cavities, mouth, esophagus, larynx, and auditory tubes all have openings into the pharynx
- tonsils form a ring of lymphoid tissue around throat (pharyngeal tonsils open into nasopharynx, lingual and palatine tonsils found in oropharynx)
- lined by mucous membrane
8
Q
Describe the function of the pharynx.
A
- passageway for food and liquids
- air distribution; passageway for air
9
Q
Describe the structure of the larynx.
A
- nine pieces of cartilage form framework
- thyroid cartilage (Adam’s apple) is largest
- epiglottis partially covers opening into larynx
mucous lining - vocal cords stretch across interior of larynx
10
Q
Describe the function of the larynx.
A
- air distribution; passageway for air to move to and from lungs
- voice production
11
Q
Describe the structure of the trachea.
A
- tube about 11cm long and 2.5cm wide
- extends from larynx into the thoracic cavity
- mucous lining
- c-shaped rings of cartilage hold trachea open (but allow for swallowing)
12
Q
Describe the function of the trachea.
A
- passageway for air to move to and from the lungs
- obstruction (blockage of trachea occludes the airway and, if complete, causes death in minutes)
13
Q
Describe the structure of the bronchial tree.
A
- trachea branches into right and left bronchi
- each bronchus branches into smaller and smaller tubes eventually leading to bronchioles
- bronchioles end in clusters of microscopic alveolar sacs, the walls of which are made up of alveoli
14
Q
Describe the function of the bronchial tree.
A
- air distribution
- passageway for air to move to and from the alveoli
15
Q
Describe the structure and function of alveoli.
A
- respiratory membrane (thin wall that separates pulmonary blood from alveolar air, allowing diffusion of gases
- exchange of gases between air and blood
16
Q
What is surfactant?
A
Surfactant is a substance released into alveoli to reduce surface tension and thus prevent collapse of alveoli.
17
Q
Describe the structure and function of the lungs.
A
- size - large enough to fill the chest cavity, except for middle space occupied by heart, large blood vessels, thymus, and esophagus
- apex - narrow upper part of each lung, under collarbone
- base - broad lower part of each lung, rests on diaphragm
- function - external respiration
18
Q
What is the pleura?
A
- thin membrane that lines thoracic cavity (parietal pleura) and covers outer surface of each lung (visceral pleura)
- moist, smooth, slippery serous membrane reduces friction between the lungs and chest wall during breathing
- Pleurisy (pleuritis) - inflammation of the pleura
19
Q
What are the three types of respiration?
A
- External respiration - pulmonary ventilation (breathing) and pulmonary gas exchange
- Cellular respiration - a series of chemical reactions that break down glucose to produce ATP, which may be used as energy to power many reactions throughout the body.
- Internal respiration - systemic gas exchange between the body and body cells
20
Q
Describe the basic principles of the mechanics of breathing.
A
- pulmonary ventilation includes two phases called inspiration (movement of air into lungs) and expiration (movement of air out of lungs)
- changes in size and shape of thorax cause changes in air pressure within that cavity and in the lungs
- pressure differences (gradients) cause air to move into and out of the lungs
21
Q
Describe the process of inspiration (inhalation).
A
- active process - air moves into lungs
- inspiratory muscles include diaphragm and external intercostals
- diaphragm flattens when stimulated by phrenic nerve during inspiration (increases top-to-bottom length of thorax)
- external intercostal muscles contract and elevate the ribs (increases the size of the thorax from the front to the back and from side to side)
- increase in the size of the chest cavity reduces pressure within it; air then enters the lungs by moving down its pressure gradient
22
Q
Describe the process of expiration (exhalation).
A
- quiet expiration is ordinarily a passive process
- during expiration, thorax returns to its resting size and shape
- elastic recoil of lung tissues aids in expiration
- expiratory muscles used in forceful expiration are internal intercostals and abdominal muscles
- internal intercostals (contraction depresses the rib cage and decreases the size of the thorax from the front to back)
- abdominal muscles (contraction elevates the diaphragm, thus decreasing size of the thoracic cavity from the top to bottom)
- reduction in size of the thoracic cavity increases its pressure and air leaves the lungs
23
Q
What is Tidal Volume (TV)?
A
The amount of air normally breathed in or our with each breath.
24
Q
What is Vital Capacity (VC)?
A
The greatest amount of air that one can breath out in one expiration.
25
What is Expiratory Reserve Volume (ERV)?
The amount of air that can be forcibly exhaled after expiring the tidal volume.
26
What is Inspiratory Reserve Volume (IRV)?
The amount of air that can be forcibly inhaled after normal respiration.
27
What is Residual Volume (RV)?
The air that remains in the lungs after the most forceful expiration.
28
Describe the brainstem control of respiration.
- most important central regulatory centers in the brainstem are called respiratory control centers
- medullary centers - under resting conditions the medullary rhythmicity area produces a normal rate and depth of respirations (12-18/min)
- pontine centers - as conditions in the body vary, these centers in the pons can alter the activity of the medullary rhythmicity area, this adjusting breathing rhythm
- brainstem centers - influenced by info from other parts of the brain and from sensory receptors located in other body regions.
29
Describe the cerebral cortexes role in respiration.
Voluntary (but limited) control of respiratory activity.
30
Describe the two respiratory reflexes.
- Chemoreflexes - chemoreceptors respond to changes in carbon dioxide, oxygen, and blood acid levels (receptors located in carotid and aortic bodies)
- Pulmonary stretch reflexes - respond to the stretch receptors in lungs, this protecting respiratory organs from overinflation
31
What is Eupnea?
Normal breathing
32
What is hyperventilation?
Rapid and deep respirations
33
What is hypoventilation?
Slow and shallow respirations
34
What is dyspnea?
Laboured or difficult respirations
35
What is apnea?
Briefly stopped respiration
36
What is respiratory arrest?
Failure to resume breathing after a period of apnea.
37
What is Cheyne-Stokes respiration (CSR)?
Cycles of alternating apnea and hyperventilation associated with critical conditions
38
Describe pulmonary gas exchange (exchange of gases in lungs).
- carbaminohemoglobin breaks down into carbon dioxide and hemoglobin
- carbon dioxide moves out of lung capillary blood into alveolar air and out of body in expired air
- oxygen moves from alveoli into lung capillaries
- hemoglobin combines with oxygen, producing oxyhemoglobin
39
Describe systemic gas exchange (exchange of gases in tissue).
- oxyhemoglobin breaks down into oxygen and hemoglobin
- oxygen moves out of tissue capillary blood into tissue cells
- carbon dioxide moves from tissue cells into tissue capillary blood
- hemoglobin combines with carbon dioxide, forming carbaminohemoglobin
40
Describe the blood transport of oxygen.
- only small amounts of oxygen can be dissolved in blood
- most oxygen combines with hemoglobin to form oxyhemoglobin (HbO2) to be carried in blood
41
Describe the blood transport of carbon dioxide.
- dissolved carbon dioxide - 10%
- carbaminohemoglobin - 20%
- bicarbonate ions - 70%
