Respiration and Gas Exchange in Humans Flashcards
Features/Adaptation of Gas Exchange in humans (4)
large surface area
thin surface
good blood supply
good ventilation of air
Uses of energy in living organisms (7)
muscle contraction
protein synthesis
cell division
active transport
growth
passage of nerve impulses
maintenance of body temperature
Define aerobic respiration (2)
chemical reactions in cells
use oxygen to break down nutrient molecules to release energy
Aerobic respiration word equation
glucose + oxygen –> carbon dioxide + water
Balanced chemical equation for aerobic respiration
C6H12O6 + 6O2 –> 6CO2 + 6H2O
Define anaerobic respiration (2)
chemical reaction in cells
break down nutrient molecules to release energy without using oxygen
Anaerobic respiration releases more energy per glucose molecule than aerobic respiration. True or False?
False
Word equation for anaerobic respiration in yeast
glucose –> alcohol/ethanol + carbon dioxide
Word equation for anaerobic respiration in muscles
glucose –> lactic acid
Balanced chemical equation for anaerobic respiration in yeast
C6H12O6 –> 2C2H5OH + 2CO2
What happens during vigorous exercise (3)
lactic acid builds up in muscles and blood
causes cramps
causes oxygen debt
How is oxygen debt removed after exercise (2)
fast heart rate transports lactic acid in blood from muscles to liver
deeper/faster breathing supplied oxygen to break down lactic acid
Composition of inspired air (3)
21% oxygen
0.04% carbon dioxide
variable water contents (depends on environment)
Composition of expired air (3)
16% oxygen
4% carbon dioxide
saturated in terms of water content
What cells produce mucus
goblet cells
Relationship between exercise intensity and rate/depth of breathing (7)
cells respire faster during exercise to provide necessary energy for muscle contraction
hence produce more carbon dioxide
carbon dioxide is acidic
can alter blood ph/disrupt enzyme activity
trigger blood ph sensors in brain
brain sends impulse to lungs to increase breathing rate/volume
removes excess carbon dioxide
Which is more damaging?
An increase in carbon dioxide concentration or a decrease in oxygen concentration
increase in carbon dioxide concentration
Experiment to investigate anaerobic respiration (5)
boil glucose solution to sterilise/remove oxygen (for anaerobic respiration)
cool temperature (otherwise yeast will die)
place layer of oil above glucose to prevent oxygen from entering
yeast will anaerobically respire producing alcohol and carbon dioxide
limewater will turn cloudy showing carbon dioxide is present
Direction of air entering lungs (6)
mouth
larynx
trachea
bronchi
bronchioles
alveoli
Purpose of mucus
traps microorganisms/dust particles breathed in
Where are cilia/ciliated cells found (2)
trachea lining
bronchi lining
Purpose of cilia (2)
sweep in co-ordinated motion
move mucus up trachea to back of mouth to be swallowed
Define ventilation
movement of air across alveolar surface
What are alveoli covered in
capillaries
Alveoli Adaptations (4)
thin walls
moist lining
large surface area
high concentration gradient
How does a moist lining improve gas exchange
gases dissolve before they diffuse
Why does water vapour concentration increase in expired air
water evaporates from moist lining of alveoli due to warmth of body
Components of cigarette smoke (3)
carbon monoxide
nicotine
tar
How does carbon monoxide damage the body
reduces amount of oxygen blood can carry
How does nicotine damage the body (3)
increases heart rate
puts strain on heart
increases risk of stroke
How does tar damage the body (5)
causes breakdown of alveoli walls
causes alveoli to merge together
reduces surface area
leads to emphysema
increases chances of lung cancer
Name 2 lung diseases
bronchitis
emphysema
What disease can smoking cause
Chronic obstructive pulmonary disease
How does bronchitis affect the body (2)
causes inflammation which narrows airways
causes mucus to block airways
How does emphysema affect the body (3)
damages alveoli
air becomes trapped in alveoli
reduces gas exchange efficiency
Name of gas exchange surface in humans
alveoli
Name of the tissue that forms C-shaped structures in the wall of the trachea
cartilage
Function of cartilage (2)
supports trachea
allows movement of air
Describe the effects on the thorax of contraction of the diaphragm (2)
volume increases
pressure decreases
