Download Respiration

Respiration
Content
• Human Gaseous Exchange
• Aerobic Respiration
• Anaerobic Respiration
Learning Outcomes:
Candidates should be able to:
• (a) identify on diagrams and name the larynx, trachea, bronchi, bronchioles, alveoli
and associated capillaries and state their functions in human gaseous exchange.
• (b) state the characteristics of, and describe the role of, the exchange surface of the
alveoli in gaseous exchange.
• (c) describe the effect of tobacco smoke and its major toxic components – nicotine,
tar and carbon monoxide, on health.
• (d) define and state the equation, in words only, for aerobic respiration in humans.
• (e) define and state the equation, in words only, for anaerobic respiration in humans.
• (f) describe the effect of lactic acid in muscles during exercise.
Respiration
Atmosphere
external nostril
nasal passages
nasal passages
pharynx
external nostril
pharynx
bronchi
larynx (voice box)
trachea (wind pipe)
larynx
trachea
bronchioles
bronchi
bronchioles
cluster of air sacs
(alveoli)
Alveoli
2
Respiration
Parts
Functions
Larynx
Contain vocal cords to produce sound
Trachea
Allows air to enter and leave from the bronchi.
- Supported by cartilage rings to hold it upright and ensure open
airway
- Epithelium secretes mucus to trap dust particles
- Cilia lining helps to sweep the trapped dust particles up into
the pharynx to be swallowed or expelled.
Bronchi
Trachea divides into two bronchi for gaseous exchange
Bronchioles
Each bronchiole ends in a cluster of air sacs called alveoli
Alveoli
Where gaseous exchange takes place as it is enclosed by a
network of capillaries
Respiration
Gaseous exchange in alveoli is due to
Alveolar wall
concentration gradient
Thin film of
(one
cell
thick/
• Alveolar air has a higher concentration
moisture
single
layer
of
cells)
of oxygen but a lower concentration of
Blood with high
carbon dioxide than blood capillaries
concentration of
oxygen
entering the lungs
• Gaseous exchange takes place by
O2
diffusion in the lungs
CO2
Blood with low
concentration of
oxygen
Alveolus
Blood capillary
Respiration
Adaptations of alveoli
Structure/ structure
Function
 Sac-shape and large number  Provide a large surface area to
of alveoli
increase rate of diffusion
 Only one-cell thick
(single layer of cell)
 To increase the rate of diffusion of
gases through it
 Surfaces are covered with a  Allows oxygen and carbon dioxide to
thin film of moisture
dissolve in it, hence faster rate of
diffusion
 Enclosed by a network of
capillaries
 To maintain the diffusion gradient
Effects of Tobacco Smoke and its Components
Components
1) Nicotine
2) Carbon
monoxide
3) Tar
Properties of the chemicals
Effects on the body
Addictive drug
- Causes addiction to smoking
Stimulate the release of adrenaline
- Causes increased heartbeat and blood pressure
Promotes blood clotting
- Increase risk of coronary heart disease
- Blood clot may lead to stroke or heart attack.
Bind to haemoglobin in red blood cell
- Reduces transport of oxygen around the body.
- Causes difficulty in breathing and may lead to death
Increases the rate of fatty deposits on
the inner arterial wall
- Increase risk of atherosclerosis
- Increase risk of coronary heart disease and heart
attack
Contains carcinogenic chemicals
- Causes cells to divide abnormally and leads to lung
cancer
Paralyses cilia lining the air passages
- Dust particles trapped in the mucus lining the
airways cannot be removed, causing violent coughing
- Increase risk of bronchitis (inflammation of bronchi)
and emphysema (damaged alveoli walls, hence
reduce uptake of oxygen)
Accumulates on the surface of alveoli
- Blockage in the air sacs. Hence reduces rate of
diffusion of oxygen into alveoli
Respiration
Aerobic respiration
• Glucose + oxygen  Carbon dioxide + water + large amount of energy
Anaerobic respiration (Muscle cells)
• Glucose  lactic acid + small amount of energy
Anaerobic respiration (yeast cells)
• Glucose  Carbon dioxide + ethanol + small amount of energy
Rate of respiration
• Breathing rate/ pulse rate increases during
exercise because muscle tissues require
more energy and rate of respiration
increases. Hence, the heart beats faster to
increase the rate of transport of oxygen to
muscle tissues and increase rate of
transport of waste products away from
muscle tissues.
Respiration
Effects of lactic acid in muscles during exercise:
• Lactic acid is toxic
• Accumulation of lactic acid causes muscle fatigue, pain
or cramps
• Leads to oxygen debt (oxygen debt = extra oxygen
needed to remove the lactic acid produced). Hence,
breathing rate remains fast after exercise, e.g panting
After exercise, lactic acid is transported to the liver, where it
is either oxidized directly to produce energy, or converted
back into glucose for use in muscles.
Respiration
AEROBIC RESPIRATION
ANAEROBIC RESPIRATION
Presence of oxygen
Absence of oxygen
Large amount of energy is
released
Little amount of energy is released
Water and carbon dioxide are byproducts
Ethanol and carbon dioxide are
by-products (yeast)
Lactic acid and carbon dioxide are
by-products (muscle cells)