mod9 (resp) Flashcards
ventilation
movement of air in and out of lungs
respiration
exchange of gases at the cellular level
external respiration
O2 brought into lungs is picked up by blood in lung capillaries, which gives up its CO2 in exchange
Internal Respiration
blood delivers O2 to body tissue cells and collects CO2 from these cells
upper respiratory tract
nose, nasal cavity, pharynx and associated structures
lower respiratory tract
larynx, trachea, bronchi and lungs
conducting zone
series of interconnecting cavities and tubes that filter, warm and moisten air and conduct air into lungs
respiratory zone
consists of tissues within the lungs where gas exchange occurs btw air and blood
nasal cavity
space inside the internal nose; below cranium and above mouth
nasal septum
divides nasal cavity into right and left sides
nasal conchae
form the lateral walls of nasal cavity; produces sound as air moves through
goblet cells
within mucous membrane of nose; produce mucous to moisten air and trap dust
ciliated cells
within mucous membrane of nose; moves air along toward internal nares
nasopharynx
connects with internal nares with two openings to eustachian tubes; receives mucus packages which are moved by cilia to the mouth; ***contains pharyngeal tonsils
oropharynx
middle portion of pharynx; opens into mouth and nasopharynx; palatine and lingual tonsils exist here; passage for air and food
larynx functions
open airway
can direct food or air (Switching mech)
produce sound
thyroid cartilage
cartilage that makes up larynx; male sex hormone causes it to enlarge (adam’s apple); epiglottis attaches to thyroid cartilage
cricoid cartilage
other type of cartilage that forms larynx; composed of hyaline cartilage
movement of larynx/pharynx during swallowing
pharynx and larynx rise, elevation causes epiglottis to form a lid over larynx so that food will enter the esophagus
false vocal chords
in larynx; functions to hold breath against pressure of thoracic cavity (don’t produce sound)
true vocal chords;
produce sound; lower folds made of elastic ligaments that stretch btw pieces of rigid cartilage; when muscles contract this tightens the ligaments causing chords to vibrate (**greater the pressure the louder the sound_
How is pitch controlld?
pitch is controlled by tension of true vocal chords; lower sounds are produced by decreasing muscular tension (males have longer and thicker chords causing them to vibrate slower and produce lower pitch)
trachea
anterior to esophagus; from larynx to 5th thoracic vertebra then divides into R and L primary bronchi;supported by stack of 16-20 hyaline rings connected by ligaments
mucous membrane lining trachea is compose of:
ciliated cells (moves particles TOWARDS pharynx), goblet cells and basal cells
parietal pleura
pleural membrane that is attached to chest wall and diaphragm
visceral pleura
pleural membrane that is attached to the lungs
cardiac notch
indentation on the left lung in which the heart lies (left lung is about 10% smaller than right lung)
Pleural sac/cavity
a POTENTIAL space rather than actual space; filled with fluid
alveolar sacs
two or more alveoli that share a common opening to the alveolar duct
where does exchange of gases occur
in respiratory bronchioles
exchange of O2 and CO2 btw air sacs in lungs and blood
takes place by diffusion across alveolar and capillary walls (form respiratory membrane)
respiratory membrane consists of:
layer of alveolar cells that from walls of alveolus
layer of epithelial basement membrane underlying alveolar cells
capillary basement membrane that is fused to epithelial basement
endothelial cells of capillary wall
movement of O2 and CO2 in alveoli
O2 moves across alveolar wall from ALVEOLUS to capillary lumen, while CO2 moves in opposite direction from lumen across alveolar wall into alveolar space
Quiet Inspiration (breathing at rest) (***alveolar pressure exceeds atmospheric pressure causing air to enter lungs)
active process; contraction of external intercostals and diaphragm; these contractions increase volume of thoracic cavity pulling the lungs open; this cause pressure inside lungs (alveolar pressure) to decrease causing air to enter lungs
Expiration
passive process; external intercostals relax and lungs recoil
breaths at rest (# and amount of air moved/breath)
12 breathes/min; each inhalation/exhalation moves about 500ml of air
tidal volume
volume of one breath (ie. 500ml)
minute ventilation (MV)
total volume of air inhaled and exhaled each minute (breathing rate x tidal volume)
Anatomic Dead space
conducting airways that hold about 30% of tidal volume and does not participate in gas exchange
residual volume
after exhalation considerable air remains in the lungs and airways (1200ml in males, 1100ml in females)
total lung capacity
tidal volume + inspiratory and expiratory reserve volume + residual volume
Inspiratory capacity
sum of tidal volume and inspiratory reserve volume
Functional residual capacity
sum of residual volume and expiratory reserve volume
vital capacity
sum of inspiratory reserve volume, tidal volume, and expiratory reserve volume
Partial pressure
concentration of gas in expressed as its partial pressure; when its higher in one area than in another, the gas will move to area of lower partial pressure
process of internal respiration (systemic gas exchange)
at tissue caps; O2 unloads and CO2 is picked up; the pO2 in blood is higher than that in the tissues, therefore O2 enters tissue, pCO2 is opposite
factors influencing amount of O2 released by hemoglobin (3)
CO2: as pCO2 rises in tissues; Hb releases O2 readily
Acidity: in acidic enviro, Hb releases O2 more readily
Temp: as temp increases so does amount of O2 released from Hb
*** all of these are from active metabolism
CO2 transported in blood in 3 main forms:
- dissolved CO2 (7%) in blood plasma
- bound to amino acids (23%) usually bound to Hb (carbaminohemoglobin); high pCO2 promotes formation of carbaminohemoglobin
- bicarbonate ions (70%)
chloride shift
movement of negative ions that maintains the electrical balance btw blood plasma and RBC cytosol
as blood passes through pulmonary capillaries in the lungs:
CO2 dissolved in plasma will diffuse into alveolar air
CO2 combined with Hb will split and diffuse into alveoli
HCO3 reenter RBCs from plasma and combine with H to form carbonic acid which splits into CO2 and water
3 areas of brain control respiration:
cerebral cortex, medulla, pons
cerebral cortex
controls voluntary breathing; holding breath can decrease pO2 and increase pCO2 and increase H; at this point negative fb in medulla will be activated; overriding voluntary breathing
negative FB control of breathing in response to change in blood O2, CO2 and H (pH level)
some stimulus increases pCO2 (or decreasing pO2 or pH)
PERIPHERAL AND CENTRAL chemoreceptors send nerve impulse to inspiratory centre in medulla
medulla sends nerve impulses to muscles of inhalation and exhalation to contract more forcefully and frequently
