ch 9 gas exchange Flashcards

1
Q

what is the pathway of air

A

air drawn in through nose or mouth -> pharynx -> trachea -> bronchi -> bronchioles -> alveoli

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2
Q

what is the function of the nasal cavity

A

contains hair which filters the air (traps particles of size around 5-10micrometer e.g. sand, dust and pollen)

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3
Q

how is nasal cavity adapted

A
  • large number of capillaries and moist lining which warm and humidify the incoming air respectively which prevents excessive heat and H2O loss from from the respiratory surface
  • olfactory cells for smelling
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4
Q

what is pharynx

A

a common passage for both air and food

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5
Q

what is epiglottis

A

a moveable flap in the throat which bends over to close up the glottis when food is being swallowed

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6
Q

what is the glottis

A

opening from throat to trachea

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7
Q

what is the larynx

A
  • the voice box (adam’s apple)

- sits on top the trachea

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8
Q

what are the functions of larynx

A
  • voice production
  • acts as a valve; during swallowing, the larynx is raised and comes in contact with the epiglottis and forms a lid to close off the trachea to prevent choking
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9
Q

what is the trachea

A

branches into the left and right bronchi (bronchus-singular) which lead air into and out of the lungs

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10
Q

what is the bronchus

A

-left and right bronchi branch further into smaller and smaller tubes and end up in alveoli

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11
Q

what is the alveoli

A

branching into alveoli increases surface area:volume ratio and facilitates gas exchange in alveoli

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12
Q

what are the microscopic structures

A
  • cartilage
  • goblet cells
  • smooth muscle
  • cilia of epithelial cells
  • blood vessels
  • elastic fibre
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13
Q

what is the function of cartilage

A
  • keeps the airways open to reduce air resistance and allow rapid air flow
  • prevents the tube from collapsing or bursting when the air pressure changes during breathing
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14
Q

what is the arrangement of cartilage

A
  • c shaped cartilage rings in interior of trachea

- irregular cartilage blocks in bronchi

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15
Q

where are goblet cells found

A

in between the ciliated epithelial cells

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16
Q

what is the function of goblet cells

A
  • produce and secrete mucus

- moist lining also humidifies the incoming air to prevent desiccation of respiratory surfaces

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17
Q

what is mucus

A

a slimy solution of mucin, which is made up of glycoproteins with many carbohydrate chains to make them sticky to trap air particles in inhaled air (e.g. sand, dust, pollen, bacteria, fungal spores and viruses)

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18
Q

where is smooth muscle found

A

at the posterior side of trachea and bronchi arranged transversely and longitudinally

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19
Q

what is the function of the smooth muscle

A
  • expands and recoils to adjust the diameter and length of trachea and bronchi during inhalation and exhalation
  • the muscle can also contract during coughing to force the air out
  • at terminal bronchiole, can contract or relax to adjust the diameter of the terminal bronchiole
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20
Q

how does smooth muscle help during exercise

A

smooth muscle relaxes, so the diameter of the terminal bronchiole increases, increasing air flow to the alveoli

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21
Q

what is the function of the cilia of epithelial cells

A

the cilia, each with a hooked end, beat continuously to sweep the mucus and trapped particles upwards into the pharynx

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22
Q

function of blood vessels in gas exchange

A
  • warm the incoming air to body temperature to prevent excessive heat loss
  • carries macrophage and other white blood cells which can leave the capillaries into the lining of air passages to remove dust particles and pathogens
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23
Q

where is elastic fiber found in the gas exchange system

A

found in alveolar walls

24
Q

function of elastic walls in gas exchange system

A
  • found in alveolar walls
  • elastic to allow alveoli to expand according to air volume inhaled during inspiration and recoil during expiration to help force the air out efficiently
25
Q

in which airways is lumen present in

A

trachea, bronchus, T. bronchiole, R. bronchiole, alveolus (all)

26
Q

properties of epithelium in the trachea

A

(see diagram in table)

  • ciliated
  • pseudostratified
  • columnar
27
Q

properties of epithelium in bronchus

A
  • goblet cell

- mucin droplets

28
Q

properties of epithelium in T. bronchiole

A
  • ciliated

- columnar

29
Q

properties of epithelium in R. bronchiole

A
  • ciliated

- cuboidal

30
Q

properties of epithelium in alveolus

A
  • no cilia

- squamous

31
Q

in which airways is goblet cell present it

A

trachea and bronchus

32
Q

which airways have connective tissue

A

trachea, bronchus, T. bronchiole, R.bronchiole, alveolus (all)

32
Q

which airways have connective tissue

A

trachea, bronchus, T. bronchiole, R.bronchiole, alveolus (all)

32
Q

which airways have connective tissue

A

trachea, bronchus, T. bronchiole, R.bronchiole, alveolus (all)

33
Q

which airways have connective tissue

A

trachea, bronchus, T. bronchiole, R.bronchiole, alveolus (all)

34
Q

which airways have smooth muscle

A

trachea, bronchus, T. bronchiole, R. bronchiole

35
Q

which airways have elastic fibre

A

trachea, bronchus, T. bronchiole, R. bronchiole, alveolus (all)

36
Q

what type of cartilage does the trachea have

A

c-shape

37
Q

what type of cartilage does the bronchus have

A

fragmented

38
Q

how many trachea are there

A

1

39
Q

how many bronchus are there

A

2

40
Q

how many T. bronchiole are there

A

48000

41
Q

how many R. bronchiole are there

A

300000

42
Q

how many alveoli are there

A

3x10^9

43
Q

what is the size differences between the airways

A

the diameter decreases from trachea to alveoli, from 1.8cm to 250micrometer

44
Q

what cells are present inside an alveolus

A
  1. endothelial cell (capillary)
  2. red blood cell
  3. macrophage
  4. white blood cell
  5. squamous epithelial cell
  6. surfactant secreting cell
45
Q

where does gas exchange occur

A

gas exchange occurs between the air in the alveoli and the blood in the capillary
(the site of gas exchange is between the alveolus and capillary)

46
Q

what is the formula for rate of diffusion (ficks law)

A

diffusion rate = (surface area x concentration gradient)/length

47
Q

functions of surfactant

A
  1. moisten gas exchange surface on alveoli
    - to allow gases to diffuse across the alveolar wall
  2. reduce surface tension (due to extensive H bonds in water surface)
    - prevents alveolus from collapsing
  3. kill bacteria
48
Q

how is the gas exchange system adapted to increase surface area:volume ratio

A
  • branching of tubes leads to millions of alveoli

- alveoli are small

49
Q

what are the features of gas exchange system to increase diffusion rate

A
  • surfactant
  • large surface area to volume ratio
  • short diffusion distance
  • steep diffusion gradient
  • umbrella shaped red blood cells
50
Q

how is the gas exchange system adapted for short diffusion distance

A

-alveolus and capillary are very close to each other and only 2 cells apart/thick
(2 squamous epithelial cells thick)

51
Q

how is the gas exchange system adapted for steep diffusion gradient

A

ventilation of the lungs for continuous blood flow

  • oxygenated blood transported away
  • deoxygenated blood transported to alveolus
  • partial pressure of O2 is high due to constant breathing
52
Q

how are red blood cells adapted for gas exchange

A

the red blood cell squeezes through the capillary
-it can do this because it is small (7micrometer) and flexible due to specialized cytoskeleton
the red blood cell is also umbrella shaped for greater surface area : volume for rapid uptake of O2

53
Q

Where are the lungs located?

A

Thoracic chest cavity

54
Q

How are the lungs (area around lungs) adapted to ventilation

A
  • Lungs are surrounded by an airtight space between the 2 pleural membranes
  • pleural cavity between the 2 pleural membranes