respiratory 1

Question 1

respiration = ____, specifically…

Answer 1

gas exchange b/w environment and organism
specifically, the uptake of oxygen and the excretion of CO2

Question 2

describe the steps of gas exchange during respiration

Answer 2

oxygen uptake: get oxygen from environment into lungs –> get oxygen from lung into blood –> oxygen transported to circulatory system by blood in bulk transport –> exchange b/w blood and tissues –> O2 then exchanged b/w intracellular parts of tissue and mitochondria where it is used by oxidative phosphorylation to generate ATP (that process in mitochondria produces CO2, the major toxic waste product from carbohydrate metabolism) –> starts taking reverse route to be eliminated from body, CO2 diffuses from mitochondria into tissue –> from tissue to blood –> carried in bulk transport to lung where it diffused from blood into airspace in lung –> expelled into atmosphere

Question 3

list the 5 respiration events by name

Answer 3

1- breathing/ventilation (air from environment into lungs)
2- external respiration (exchange of gases b/w air in lungs & blood)
3- gas transport by blood (bulk transport- transport of O2 to body cells & return of CO2)
4- internal respiration (exchange gases b/w blood and body cells)
5- cellular respiration (actual use of oxygen in processes to generate ATP and production of Co2)

Question 4

in general, lungs hold ___L of air, they have a huge ____…

lungs weigh ___, and at rest, contain ___ mL of blood…can hold ___mL during exercise

Answer 4

4L, huge surface area (75-80 sq meters)

600 grams, contain 60-140 mL of blood –> it increases during exercise, can hold up to 200 mL of blood when heart pumping blood into lungs thru exercise

Question 5

structurally, lungs can be divided into 2 structural groups:

Answer 5

airways (upper & lower) and terminal lung sacs (alveoli)

Question 6

airways of the lungs can be divided into ___ and ___, which each consist of…

Answer 6

upper airways: nose, sinuses, pharynx, vocal cords

lower airways: trachea, left & right bronchus, bronchioles

Question 7

airways of the lung have 3 functions:

Answer 7

1- deliver air into deep parts of lung (into alveoli, terminal airsacs)
2- warm the air, airways give up a little bit of heat so that its as close to core body temp when in deepest parts of lungs)
3- moisturize the air (as breathe in, add a little bit of water vapor to air to prevent deep parts of lungs from drying out)

Question 8

overall, the functions of the airways of the lung do what?

Answer 8

condition the air as it goes into lungs, they act as first line of defense to keep germ-free

Question 9

describe the structural branching of the lower airways

Answer 9

trachea branch into left & right bronchus –> these branch into about 1 million bronchioles in the lung –> the alveoli (terminal air sacs) branch off the ends of the bronchioles (300 alveoli at the end of each bronchiole, so 300 million alveoli in lungs)

Question 10

how much volume of air does the nose hold?
volume of air that goes b/w lungs per day = ___
describe nose

Answer 10

20 mL of air
10,000-15,000 L of air

• nose has huge surface area due to all the folds called the nasal terminae
• lots of secretory cells in nose that secrete immunoglobulins, interferons help keep the air sterile as you breathe in
• nasal cavity acts as a filter (lined with hairs), anything above 10 microns gets filtered out
• surrounding nose are sinus cavities- lined with cilia, mucus-producing cells (trap particles & clear sinus cavity)

Question 11

what do the lower airways function in? what are the cell types in them?

Answer 11

function in defense

epithelial cells & goblet cells (5:1 ciliated cells to goblet cells)

Question 12

epithelial cells of the lower airways are lined with ___ that face…

why do airway epithelial cells have their name?

Answer 12

cilia that face the airways

epithelial refers to position, means these cells contact air

Question 13

goblet cells of the lower airways produce what?

Answer 13

produce and secrete mucus, mucus is only produced in patches along airways in goblet cells, then beating of cilia spreads the mucus evenly across surface of the airways (mucus traps foreign particles and the cilia beats upwardly toward throat to expel the foreign stuff)

Question 14

normally mucus is fairly ___, it is produced by the transport of what ion? explain

Answer 14

watery, loose

produced by transport of Cl ions out of goblet cells into the paricilliary layer (Cl pulls water with it across osmotic gradient)- main Cl channel responsible is CFTR (cystic fibrosis transmembrane regulator), when it functions normally, outward movement of Cl is greater than inward movement of sodium –> more water moves out, making parcilliary layer watery and loose (gives mucus a water consistency to be easily moved by cilia)

Question 15

what do the chemical compounds of cigs damage in the lower airwaud?

Answer 15

kill cilia and makes goblet cells stop producing mucus, it damages the first line of defense in trachea, more irritation

Question 16

what materials/muscle are the upper and lower airways lined with?

Answer 16

upper airways- trachea runs parallel to esophagus, trachea lined with both cartilage & smooth muscle- cartilage is formed in a C, where it meets the esophagus, there is no cartilage –> allows esophagus to expand when swallowing food

lower airways only lined with smooth muscle (especially bronchioles)- smooth muscle layers are thick enough to prevent diffusion of oxygen from airways and into blood (no exchange of oxygen b/w airways and lungs- diffusion distance is too big) –> so the airways are termed the anatomical dead space of the lung

Question 17

what equation describes ventilation of the lungs?

Answer 17

Boyle’s law PV = nRT

pressure and volume in lung are inversely related - when volume increases, pressure decreases

Question 18

lungs are inflated by the action of these 2 muscles…explain how they change the pressure and volume of lungs

Answer 18

diaphragm and intercostal muscles

these expand chest cavity (diaphragm flattens out and intercostal allows chest cavity to expand –> increases volume of lungs –> that lowers the pressure inside your lungs, but atmospheric pressure stays the same (air moves down pressure gradient from environment to lungs), atmospheric pressure is 760 mmHg, when lungs expand, pressure in lungs drops to 757 mmHg (lower pressure than surrounding, so air moves into lungs b/c air has such low density, that even a small pressure change allows it to move) –> when inhale, diaphragm and intercostal muscles activated (diaphragm activated by phrenic nerve and intercostal activated by intercostal nerve) –> they contract, diaphragm pulls down, intercostal pulls out –> lungs volume increases –> pressure drops by 33 mmhg, air fills lung

Question 19

inspiration is a ___ process & expiration is a ___ process

Answer 19

active, activates muscles to move the volume

passive, especially at rest (muscles relax and spring back to normal positions)

Question 20

the plural cavity is a little layer of ___ between the lining of the ___ and intestinal lining of the ___

the lining of the lung is called the ___
lining of chest cavity is called ____

Answer 20

fluid
lung & chest cavity

visceral pleura
parietal pleura

Question 21

describe pleura pressure

Answer 21

pleura pressure is negative, which helps the lung stick to the chest wall

when inhale, diaphragm/lungs pull down and chest pulls out, this could potentially tear the lung away from the lining of the chest cavity…but the negative pressure of pleura increases which keeps the lung stuck to chest cavity and allows it to inflate/deflate

Question 22

alveoli (terminal air sacs) are ___ sacs that bud off the end of the ___

Answer 22

blind-ending
bronchioles (look like grapes hanging off stem)

Question 23

what is the avg alveoli diameter? how does its diameter change with respiration?

Answer 23

avg diameter is 200 microns (but not all same size, range from 50-300 microns)

each individual alveolus will expand its diameter during inhalation and reduce its diameter during exhalation

Question 24

each individual alveolus is surrounded by ___…

alveoli are connected together by ___…

Answer 24

15-20 capillaries –> 6 billion capillaries in the lung

big web of capillaries that surround alveoli of the lung (looks more like a sheet of blood tho)

connected together by smaller alveolar pores - this helps even out air flow to all the alveoli when you breathe

Question 25

alveoli have ___ surface area

describe the 3 main cell types in alveoli

Answer 25

huge SA

type I alveolar epithelial cell - thin & flat (.1 microns), these are the main cell type that make up alveolar cell wall

type II alveolar epithelial cell - little thicker & bigger (much less abundant), they synthesize and secrete pulmonary surfactant (a glycoprotein/phospholipid mix that coats inside of alveolar wall)

alveolar macrophage - a hunter-killer cell, tracks down bacteria, engulfs and digests them

Question 26

which cell type in alveoli synthesize and secrete pulmonary surfactant

Answer 26

type II alveolar epithelial cells

Question 27

the distance b/w alveolar air space and the blood is called the ___…

Answer 27

respiratory membrane - the distance oxygen has to cross to get from air in lung into the blood (membrane is very thin

Question 28

b/c airways act as first line of defense, alveoli of the lung are always considered to be ____, in normal conditions, all alveoli are ___ and functions in ____

Answer 28

aseptic (germ-free)
open and function in absorbing oxygen into blood

Question 29

if there is infection/injury, some alveoli may be blocked and not function …so what are they called

Answer 29

air in those alveoli represent dead air/dead space, these blocked alveoli are called physiological dead space (airways + any non-functioning alveoli)

Question 30

describe the experiment with rats and alveolar macrophages

Answer 30

rat spits out fluid, including macrophages –> u centrifuge them and study how they track down bacteria (signals and receptors used to track the chemical scent of bacteria) –> have a capillary tube and put bacteria on one end and put macrophages in tube and you watch how the macrophages track and eat the bacteria

hook rat up to cig smoking machine –> alveolar macrophages turn black –> test their ability to clear bacteria (if no smoke, kills/clears all bacteria), but when given smoke, only 5% clearing, lose their ability to track the bacteria

so cig smoke kills alveolar macrophages

Question 31

pulmonary surfactant is a chemical liquid lining of membrane consisting of ___ and ___, it is ___ molecule(s) thick that lines the inside surface of the lung

Answer 31

glycoproteins and phospholipids
1

Question 32

what is the unique and main feature of pulmonary surfactant?

Answer 32

its surface tension is directly proportional to alveolar diameter

surface tension is the lateral attraction of molecules for each other, pull toward each other –> pulmonary surfactant molecules pull toward each other laterally across alveolar surface, the pulling tightens the surface

Question 33

what equation describes the relationship of surface tension and alveolar diameter

Answer 33

LaPlace equation
Pressure = 4 x surface tension / radius

surface tension puts an inward pressure on the gas inside a bubble –> ST, inward pressure, and diameter come together to form LaPlace equation

Question 34

alveoli are ___ that bud off the bronchioles, they have ___ so they are all connected together, gas can move freely thru all the alveoli

what would happen if alveoli were simply lined with water?

Answer 34

bubbles, alveolar pores

one small alveoli (radius 0.05) & one large alveoli (radius 0.3) , they both have constant surface tension –> if plug into LaPlace equation, smaller bubble will always have larger inward compressing pressure

–> if this were the case in lungs, when inhale, the pressure in the different alveoli would be diff (pressure larger in smaller alveoli, when pressures try to equalize, air moves from smaller alveoli into bigger ones, the smaller ones would collapse and be functionally useless in taking up oxygen (so having them only lined with water would be bad)

but instead, lungs lined with pulmonary surfactant which have variable ST :)

Question 35

what is the FIRST impt function of pulmonary surfactant?

Answer 35

pulmonary surfactant equalizes surface tension b/w diff diameter bubbles and allows them to be open and functional during inhalation & exhalation

smaller diameter have lower ST and larger diameter have higher ST –> pressures in both are same

Question 36

what is the SECOND impt function of pulmonary surfactant?

Answer 36

surfactant makes the alveolar wall flexible, easy to inflate/expand because lower surface tension

• involves when alveoli are at their smallest diameter, this happens at beginning of inhalation, when empty –> at this point, pulmonary surfactant ST is 5 dynes, so alveolar wall is most flexible and easy to fill with no resistance –> this reduces the work load of respiratory muscles for inhaling
• if alveoli were lined with just water, even at rest when empty, ST = 70 dynes, work load would be huge b/c so much resistance and wall is most rigid

the max surfactant surface tension is 45 dynes (occurs when surface area of lung is largest when inflated) –> the high ST provides about 2/3 of the elastic recoil that helps shrink the alveoli, helps during passive exhalation

Question 37

what is the THIRD impt function of pulmonary surfactant?

Answer 37

its max ST (45 dynes) is still well below the ST of water (70), ST squeezes and creates inward pressure, this draws fluid into alveoli from interstitial space (air pressure has to balance inward suction created by ST) –> at 45 dynes, the max ST is low enough so the air pressure can act against it and prevent fluid from leaking into the alveoli

if alveoli were lined with water (70) –> creates huge inward pressure/suction, pulls water into alveoli from interstitial space –> results in pulmonary edema –> renders alveoli useless for exchanging oxygen