respiratory system

Question 1

structurally

Answer 1

upper respiratory system- clena, humidify and warm incoming air, reabsorb head and water from outgoing air
lower respiratory system- conducts air to the gas exchange surfaces, gas exchange

Question 2

functionally

Answer 2

conducting zone- passageways that conduct the air, as well as cleanse, humidify and warm the incoming air and reabsorb heat and water from outgoing air
respiratory zone- respiratory bronchioles, alveolar ducts and alveoli, where gas exchange occurs

Question 3

nose & nasal cavity

Answer 3

nasal cavity- mucosal epithelium- produces mucus humidifies incoming air traps particles contains antibacterial compounds
bears cilia which moves contaminated mucous to the throat

Question 4

pharynx and larynx

Answer 4

pharynx- passage way for air and food
larynx- arrangement of cartilages
open passageway for air to reach the trachea
routes food and air into the correct passageways

Question 5

trachea and lungs

Answer 5

windpipe, c shaped cartilage rings

lie within the thoracic cavity- pleural cavity
pleural fluid are within the pleural space, acts as a lubricant and adheres lungs to thoracic cavity

Question 6

respiratory tree

Answer 6

branching network pf airways starting form the trachea
conducting zone- airway becomes smaller diameter decreases
cartilage rings- cartilage plates
mucociliary escalator disappears
gain smooth muscle and elastic fibres

Question 7

respiratory zone

Answer 7

alveolar sacs and alveoli are surrounded by capillaries

the respiratory membrane formed where the alveoli connects the capillary and is site of gas exchange

Question 8

respiratory membrane

Answer 8

formed where the type 1 alveolar epithelial cells contact the capillaries
very thin hence efficient gas exchange
alveola surface is coated with alveoli fluid prevents damage, facilitates gas exchange and surfactant prevents alveolar collapse

Question 9

blood supply to the lungs

Answer 9

enters:
1. pulmonary circulation: pulmonary arteries deliver blood requiring oxygenation and nutrients for alveoli
2. bronchial circulation: bronchial arteries provide oxygenated blood to rest of the lung tissue
Leaves:
pulmonary circulation: pulmonary veins return blood to the heart

Question 10

innervation of the lungs

Answer 10

sensory fibre sends messages to respiratory centre in the brainstem to influence respiratory rhythm 
sympathetic fibres (dilate)
parasympathetic fibres (constrict)

Question 11

pulmonary ventilation

Answer 11

pressure is inversely proportional to the volume of a closed container
change in thoracic cavity
this sets up a pressure gradient= gas flows down a pressure gradient

Question 12

inspiration

Answer 12

external intercostal muscles contract and ribcage expands and lifts up

1. inspiratory muscle (diaphragm and external intercostal muscle) contract (diaphragm descends, rib cage rises)
2. thoracic cavity volume increases
3. lungs are stretched, intrapulmonary volume s=increases
4. intrapulmonary pressure drops
5. air flows into lungs down its pressure gradient until intrapulmonary pressure is equal to atmospheric pressure

Question 13

expiration

Answer 13

external intercostal muscle relax, ribcage descends and becomes smaller

1. inspiratory muscles relax (diaphragm rises, ribcage descends due to recoil of costal cartilages)
2. thoracic cavity volume decreases
3. elastic lungs recoil passively intrapulmonary volume decreases
4. pulmonary pressure rises
5. aur flows out of lungs down its concentration gradient until intrapulmonary pressure is equal to atmospheric pressure

Question 14

stops lungs from collapsing

Answer 14

surfactant reduces the surface tension of the alveolar fluid
pleural fluid sticks the parietal and visceral pleural membranes together
elasticity of the chest wall pulls the thoracic wall outwards

Question 15

passive and forced expiration

Answer 15

passive- muscle relaxation only (external intercostal and diaphragm) depends on lung recoil
forced- physical activity or specific vocalisation
internal intercostal muscle contract, further depress the ribcage
involves contraction of accessory muscles

Question 16

gas flow/ ventilation

Answer 16

dependent on a number of factors including resistance, alveolar surface tension and compliance

Question 17

resistance

Answer 17

F= P/R
resistance= opposition to gas flow
friction between air and airway walls
dependant upon airway diameter

Question 18

alveolar surface tension

Answer 18

surface tension between water molecules in alveolar in alveolar fluid
surfactant-lipid protein complex produced by alveolar epithelial cells reduced surface tension of alveolar fluid
prevents alveolar collapse
reduces effort required to expand alveolar= facilities ventilation

Question 19

compliance

Answer 19

measure of ability of the lungs and thoracic cavity to stretch
depends on: lung elasticity, alveolar surface tension , flexibility of muscles and joints of thoracic wall

Question 20

obstructive disorders

Answer 20

reduced airways diameter, reduced resistance, shortness of breath, hypoventilation

Question 21

restrictive disorders

Answer 21

reduced thoracic or lung compliance, reduced ability to change thoracic/ lung volume, effect on the mechanics of breathing- pressure gradient smaller, reduced amount of air drawn into lungs during inspiration

Question 22

external respiration

Answer 22

in conducting zone: air move down a pressure gradient via bulk flow
respiratory zone: gas moves across respiratory membrane

Question 23

partial pressure gradient for each gas

Answer 23

o2 diffuse form alveoli to pulmonary capillaries
co2 diffuse from pulmonary capillaries to alveoli
gas exchange is also influenced by how soluble the gas is in water
co2 is 20x more soluble in water than o2

Question 24

structural characteristics of respiratory membrane

Answer 24

diffusion efficiency depends on width and SA

Question 25

matching of alveolar ventilation and pulmonary blood perfusion = ventilation perfusion coupling

Answer 25

good ventilation, high o2 in alveoli, arterioles dilate increase blood flow, facilitate o2 pick up high blood pco2, bronchioles dilate, air flow increases, excess co2 removed from blood

Question 26

internal respiration

Answer 26

partial pressure gradients for each gas o2 diffuses from blood to tissues co2 fiddles from tissues to blood co2 20x more soluble in water than o2

Question 27

oxygen transport

Answer 27

oxygen poorly soluble in water however RBC and HB are highly adapted for o2 transport Hb binds to o2 reversibly at alveoli; -> Po2,

Question 28

hypoxia

Answer 28

decreased o2 at tissue cyanosis- blue tinge to skin and mucosa causes too few RBC or decreased Hb blood circulation is reduced/ blocked

Question 29

co2 transport

Answer 29

co2 is waste product and is transported by dissolving in plasma, bound to Hb and bicarbonate ions in plasma

Question 30

plasma pH

Answer 30

reaction occurs inside RBC as part of co2 transport and in the plasma as a buffer to control pH carbon dioxide+ water= carbonic acid= hydrogen + bicarbonate ion

Question 31

pH or Pco2 rises

Answer 31

increased pco2 causes ph to decrease | increased pH causes pco2 to decrease

Question 32

pco2 or pH falls

Answer 32

creased pco2 casques ph to increase | decreased ph causes pco2 to increase

Question 33

hyperventilation

Answer 33

breathe out more co2= blood pH

Question 34

hypoventilation

Answer 34

co2 accumulates= -> co2 reaction favours right hand side ->H ion levels causing