Chapter 22: Respiration Flashcards
What is ventilation?
The movement of air into or out of the pulmonary structures
What does ventilation provide?
Effective respiration
What is the epithelium in the nostril?
Stratified squamous epithelium with basement membrane (dermus)
What is the purpose of the nostril?
Air enters into the nasal cavity through the nostril.
Hairs in the nostril filter out particles when you breathe in and cleanse the air to prevent dirt from going into the lungs
Describe the sinuses.
Sinuses are connected to nasal passages but are a different structure that reduces the weight of the cranium.
Sinuses receive air when you ventilate.
What epithelium covers the nasal conchae and nasal meatus ridges?
Pseudo stratified epithelium; moist membrane with mucous present
What is the purpose of the nasal conchae and nasal meatus?
Create turbulence and increase surface area
What is the purpose of mucous?
Trap dirt (filter air) and start to humidify the air before it makes its way down to the lungs
What is the purpose of the pharyngotympanic tube?
Opening of the tube that leads back to your inner ear and drains fluid from the inner ear.
If clogged with mucous or the sinuses swell, it can’t drain so bacteria grows and infection occurs.
What is the purpose of lymphoid tissue?
Also known as an adnoid, the nasal passage is a resonating chamber that affects the sound of voice
What does the nasal cavity do if the air is cold?
Warms it
What is the purpose of the pharynx?
Tube that connects the nasal and oral cavity down to the larynx and trachea.
Chamber that connects other chambers together.
What are the pharynx parts?
Nasopharynx, oropharynx, and laryngopharynx
What is the purpose or the palatine and lingual tonsil?
Part of the lymphatic system; be present where bacteria has easy entrance to the body to protect
What is the purpose of the epiglottis?
Cover entry to voice box; open and close to prevent choking on food
Where does epithelium switch in the pharynx?
Shift from pseudo stratified epithelium to stratified epithelium by the time we get down to the oropharynx because food has to pass down. This epithelium is designed to deal with increased friction.
Which side is the esophagus on?
dorsal side
Which side is the trachea on?
ventral side
What are the 4 layers of the trachea?
- Adventitia
- Hyaline cartilage
- Submucosa
- Mucous membrane
What is the purpose of the adventitia?
Dense connective tissue; outermost layer
What is the purpose of the hyaline cartilage?
Makes up C shaped rings cartilage.
Flexible but fairly rigid.
Doesn’t form a circle.
Connected by trachealis muscle
What is the purpose of the trachealis muscle?
Smooth muscle that can contract to decrease size to minimize foreign matter entering into trachea.
Restricts airflow.
Can stretch.
When swallowing a bolus, this expands to make the esophagus larger and swallowing easier. This does not affect breathing because you don’t breath and swallow at the same time.
What is the purpose of the submucosa?
Deep to the mucous membrane.
Mucous glands that secrete watery mucous onto the surface of the mucous membrane.
What is the purpose of the mucous membrane?
Wet and heavily ciliated pseudostratified epithelium.
Produces thicker mucous.
Function is to keep membranes moist, trap dirt particles, and move mucous up towards larynx.
What is the purpose of bronchus (bronchi)?
Extend off trachea and contain certain amount of cartilage and almost no smooth muscle.
Can’t really stretch or expand.
What is the purpose of the bronchioles?
Really small; cartilage disappears and is replaced by smooth muscle.
This is where the radius of the lumen is affected and breathing is restricted.
Can regulate blood flow.
What is the purpose of the conducting zone?
No gas exchange, solely ventilation.
From the nasal to the terminal bronchiole.
What is the purpose of the terminal bronchiole?
Last bronchiole that makes up the conducting zone.
What occurs in the respiratory zone?
Respiration and ventilation take place
What is seen at the respiratory bronchiole?
appearance of alveoli
What is the purpose of alveoli?
Alveoli are individual tiny sacs where gas exchange can take place. Simple cuboidal. Still moist.
What is the purpose of the alveolar duct?
Short segment that branches off of the respiratory bronchiole that leads to an abundance of alveoli.
Has pores that lead back to the alveoli, and the pores lead back to other alveoli.
What is the purpose of alveolar pores?
Prevent overinflation.
What happens when you injure an alveoli?
They can’t be replaced and surface area is decreased
What is an alveolar sac?
Cluster of alveoli; like grapes.
Where can we regulate resistance to air flow?
Bronchioles
What is the purpose of capillaries?
What we exchange gases with
What is the purpose of elastic fibers?
Compress the alveoli.
Stretch when we inhale and the alveoli increase in size, and compress the alveoli, helping us to exhale.
How does smooth muscle help in the respiratory zone?
Aids in exhalation
What is alveolar respiration?
Exchange of gases between alveoli and capillaries
What are Type I cells of the alveolar wall?
Simple squamous.
Most abundant cell in alveolus.
What are Type II cells?
Surfactant-secreting cell.
Secrete surfactant into the alveolus, which mixes with water that lines the inside of the alveolus.
What is surfactant?
Surfacent is detergent.
Detergents can act with a polar and nonpolar molecule.
(can allow water and oil to mix)
What are resident macrophages?
Last line of defense
What is the basement membrane for simple squamous of alveolus and capillary fuse?
Share basement membrane, which helps to decrease distance for diffusion.
What does ventilation require?
Contraction/relaxation of the diaphragm to change pressures within the thoracic cavity
Inspiration: sequence of events
- Inspiratory muscles contract (diaphragm descends; rib cage rises)
- Thoracic cavity volume increases
- Lungs stretched, intrapulmonary volume increases
- Intrapulmonary pressure drops to -1 mmHg
- Air (gases) flows into lungs down its pressure gradient until intrapulmonary pressure is 0 (equal to atmospheric pressure)
Inspiration: changes in anterior-posterior and superior-inferior dimensions
Ribs elevated and sternum flares as external intercostals contract.
Diaphragm moves inferiorly during contraction.
Inspiration: changes in lateral dimensions
External intercostals contract
When is expiration passive?
Under normal conditions
Expiration: sequence of events
- Inspiratory muscles relax (diaphragm rises; rib cage descends due to recoil of costal cartilages)
- Thoracic cavity volume decreases
- Elastic lungs recoil passively; intrapulmonary volume decreases
- Intrapulmonary pressure rises to +1 mmHg
- Air (gases) flows out of lungs down its pressure gradient until intrapulmonary pressure is 0
Expiration: changes in anterior-posterior and superior-inferior dimensions
- Ribs and sternum depressed as external intercostals relax
- Diaphragm moves superiorly as it relaxes
Expiration: changes in lateral dimensions
External intercostals relax
Define Boyle’s law
The pressure of a gas varies inversely with its volume
Change in pressure during inspiration
- Pull on parietal layer of the plural membrane (connective tissue) –> volume in cavity increases –> intrapleural cavity pressure decreases (-4 mmHg –> -6 mmHg)
- Lungs expand into lower region of pressure –> volume in lungs increases –> intrapulmonary pressure decreases = intrapulmonary pressure < atmospheric pressure
- Air goes down its gradient and we inhale
What does breathing in involve the manipulation of?
2 different volumes
Passive exhalation
- Relax diaphragm and internal intercostals
- Ribs fall
- Volume in cavity decreases –> intrapleural cavity pressure increases
- Volume in lungs decreases –> intrapulmonary pressure increases
- Intrapulmonary pressure > atmospheric pressure
- Air goes down gradient and we exhale
Why do we ventilate?
So we can respirate
Does atmospheric pressure change?
No, it never changes. Everything else does
What is ventilation?
The movement of air and its contents
What does respiration involve?
The exchange of gas molecules that make up the air
What is Dalton’s Law of Partial Pressure?
The total pressure exerted by a mixture of gases is the sum of the pressures exerted independently by each gas
What is barometric pressure?
760 mmHg
What are the concentration of gases?
O2 = 20.93%
CO2 = 0.03%
N2 = 78.60%
H2O = 0.46%
What are the partial pressures of gases?
PO2 = 159.07 mmHg
PCO2 = 0.228 mmHg
PN2 = 597.36 mmHg
PH2O = 3.496 mmHg
What is residual lung volume?
When you exhale, you don’t exhale all the air and there is a little left over
Why is the partial pressure of O2 in alveoli a little over 100?
New air mixes with the old air
How is oxygen transported in the blood?
hemoglobin
How does hemoglobin load and unload oxygen?
Shape
What are the partial pressures of inspired air?
PO2 = 160 mmHg
PCO2 = 0.3 mmHg
What are the partial pressures of the alveoli of lungs?
PO2 = 104 mmHg
PCO2 = 40 mmHg
What are the partial pressures of blood leaving tissues and entering lungs?
PO2 = 40 mmHg
PCO2 = 45 mmHg
What are the partial pressures of blood leaving the lungs and entering tissue capillaries?
PO2 = 100 mmHg
PCO2 = 40 mmHg
What are the partial pressures of tissues?
PO2 < 40 mmHg
PCO2 > 45 mmHg
What happens to partial pressures when you exercise?
PO2 = decrease
PCO2 = increase
What are the 2 heme shapes?
Taut: doesn’t want to bind, empty
Relaxed: bound
When will O2 attach to hb?
When hemoglobin travels to alveoli and is exposed to high partial pressure of O2, O2 will bombard the Hb. 1 O2 will hit the heme group and bind, changing the shape and all heme groups will now be exposed.
When is a hemoglobin saturated?
When all 4 heme groups are full
What is normal saturation and what does it mean?
98%; 98% of heme groups are saturated with O2
What happens with Hb in arterial blood?
Hb is closed and bombarded with O2. Hb changes shape so O2 binds and Hb is saturated. Go to where low PO2 is, which will encourage O2 molecule to fall off
