Respiration

1
Respiration
2
Introduction

• uptake of molecular oxygen (O2) from the
  environment and the discharge of carbon dioxide
  (CO2) to the environment.
• called respiration, this process is distinct
  from, but linked to, the production of ATP in
  cellular respiration
• Provides the Oxygen needed in cell respiration
  and removes the carbon dioxide by product
• Respiratory medium, is air for terrestrial
  animals and water for aquatic animals.
• where gases are exchanged with the environment is
  the respiratory surface.
• Movements of CO2 and O2 across the respiratory
  surface occurs entirely by diffusion

3
Different Strokes for Different Folks

• In the animal kingdom the respiratory surfaces
  varies a great deal in size, function and
  location. The purpose remains the same.
• Respiratory surface must supply O2 and expel CO2
  for the entire body, the structure of a
  respiratory surface depends mainly on the size of
  the organism, whether it lives in water or on
  land, and by its metabolic demands
• occurs over the entire surface area of protists
  and other unicellular organisms.
• in most animals, the bulk of the body lacks
  direct access to the respiratory medium

4
Cont

• earthworms and some amphibians, use the entire
  outer skin as a respiratory organ.
• Gills, tracheae, and lungs are the three most
  common respiratory organs.

5
Tracheal system of insects is composed of air
tubes that branch throughout the body
6
Lungs

• are restricted to one location.
• lung is not in direct contact with all other
  parts of the body, so the circulatory system
  transports gases between the lungs and the rest
  of the body.
• have a dense net of capillaries just under the
  epithelium that forms the respiratory surface
• evolved in spiders, terrestrial snails, and
  vertebrates.
• amphibians have relatively small lungs that do
  not provide a large surface (many lack lungs
  altogether).
• most reptiles and all birds and mammals rely
  entirely on lungs for gas exchange

7
(No Transcript)
8
Flow of Air

• Air enters through the nostrils and is filtered
  by hairs, warmed and humidified, and sampled for
  odors as it flows through the nasal cavity.
• nasal cavity leads to the pharynx, and when the
  glottis is open, air enters the larynx, the upper
  part of the respiratory tract.
• In most mammals, the larynx is adapted as a
  voicebox in which vibrations of a pair of vocal
  cords produce sounds
• From the larynx, air passes into the trachea, or
  windpipe, whose shape is maintained by rings of
  cartilage.

9
Cont.

• trachea forks into two bronchi, one leading into
  each lung.
• Within the lung, each bronchus branches
  repeatedly into finer and finer tubes, called
  bronchioles
• epithelium lining the major branches of the
  respiratory tree is covered by cilia and a thin
  film of mucus.
• The mucus traps dust, pollen, and other
  particulate contaminants, and the beating cilia
  move the mucus upward to the pharynx, where it is
  swallowed or spit out--- LUGI
• the tiniest bronchioles dead-end as a cluster of
  air sacs called alveoli
• Gas exchange occurs across the thin epithelium of
  the lungs millions of alveoli

10
(No Transcript)
11
(No Transcript)
12
(No Transcript)
13
Cont

• total surface area of about 100 m2 in humans. 2
  football field side by side!!!!
• Air, O², entering the alveoli dissolves in the
  moist film and rapidly diffuses across the
  epithelium into a web of capillaries that
  surrounds each alveolus.
• Carbon dioxide diffuses in the opposite direction
• breathing, the alternate inhalation and
  exhalation of air, ventilates lungs
• Controlled by the nervous system and the
  diaphragm
• mammals ventilate their lungs by negative
  pressure breathing.
• This works like a suction pump, pulling air
  instead of pushing it into the lungs like frogs

14
Breathing
15
Breathing Cont

• Lung volume increases as a result of contraction
  of the rib muscles and diaphragm, a sheet of
  skeletal muscle that forms the bottom wall of the
  chest cavity.
• rib muscles expands the rib cage by pulling the
  ribs upward
• the diaphragm contracts and descends like a
  piston.
• changes increase the lung volume, and as a
  result, air pressure within the alveoli becomes
  lower than atmospheric pressure
• air flows from higher pressure to lower pressure,
  so air rushes into the respiratory system

16
(No Transcript)
17
Respiratory Volumes and Capacity

• Normal breathing moves about 500 ml of air with
  each breath (tidal volume TV)
• Residual volume of air after exhalation, about
  1200 ml of air remains in the lungs at all times
• Inspiratory reserve volume (IRV)
• Amount of air that can be taken in forcibly over
  the tidal volume. Usually between 2100 and 3200
  ml
• Expiratory reserve volume (ERV)
• Amount of air that can be forcibly exhaled
  approximately 1200 ml
• Vital capacity-The total amount of exchangeable
  air 3.4 to 4.8 L
• Vital capacity TV IRV ERV

18
Control

• we can voluntarily hold our breath or breath
  faster and deeper, but most of the time autonomic
  mechanisms regulate our breathing
• ensures that the work of the respiratory system
  is coordinated with that of the cardiovascular
  system, and with the bodys metabolic demands for
  gas exchange Cell Respiration!!!!!
• breathing control centers are located in two
  brain regions, the medulla oblongata and the pons
• medullas control center monitors the CO2 level
  of the blood and regulated breathing activity
  appropriately
• cues about CO2 concentration come from slight
  changes in the pH of the blood

19
Control
Carbon dioxide reacts with water to form carbonic
acid, which lowers the pH. When the control
center registers a slight drop in pH, it
increases the depth and rate of breathing, and
the excess CO2 is eliminated in exhaled air
20
Factors Affecting Breathing

• Physical factors Increased body temperature,
  Exercise, Talking, Coughing
• Volition (conscious control)
• Emotional factors- fight or flight
• Chemical factors
• Carbon dioxide levels
• Level of carbon dioxide in the blood is the main
  regulatory chemical for respiration
• Increased carbon dioxide increases respiration
• Changes in carbon dioxide act directly on the
  medulla oblongata

21
Gas Transport in Blood

• Oxygen transport in the blood
• Inside red blood cells attached to hemoglobin
• Carbon dioxide transport in the blood
• Most is transported in the plasma as bicarbonate
  ion (HCO3)
• A small amount is carried inside red blood cells
  on hemoglobin, but at different binding sites
  than those of oxygen
• opposite reaction to what occurs in the lungs
• Carbon dioxide diffuses out of tissue to blood
• Oxygen diffuses from blood into tissue

22
(No Transcript)
23
The Death Stick (Dont Smoke)

• Cigarette affects
• cilia disappear
• excess mucus produced
• lung congestion increases lung infections
• lining of bronchioles thicken
• bronchioles lose elasticity
• emphysema fifteen times more common
• lung cancer, 1/3 of all cancer deaths, is more
  common, about 90 smoke other usually have jobs
  where air in full of impurities.
• much damage repaired when smoking stops
• And those who smoke say they need this!!!!

24
We Pay For This????

• American Cancer Society estimates that cigarettes
  are responsible for about 431,000 deaths in the
  United States each year
• risks of dying from lung cancer are 23 times
  higher for male smokers and 13 times higher for
  female smokers than for nonsmokers
• smokers are at increased risk for cancer of the
  larynx, oral cavity, esophagus, bladder, kidney,
  and pancreas.
• About 48 million people in the United States
  smoke an estimated total of 430 billion
  cigarettes each year
• the average cigarette contains around 4,000
  chemicals, some of which are highly toxic and at
  least 43 of which cause cancer

25
Smoking BAD!!!!!!!!!!!!

• Smoking causes a fivefold increase in the risk of
  dying from chronic bronchitis and emphysema, and
  a twofold increase in deaths from diseases of the
  heart and coronary arteries. Smoking also
  increases the risk of stroke by 50 percent40
  percent among men and 60 percent among women.
  Other research has shown that mothers who smoke
  give birth more frequently to premature or
  underweight babies

26
Why Smoke??

• Recent findings may explain why cigarettes are
  addictive. An unknown component of tobacco smoke
  appears to destroy an important brain enzyme,
  monoamine oxidase B (MAO B). The enzyme is vital
  for breaking down excess amounts of dopamine, a
  neurotransmitter that triggers pleasure-seeking
  behavior. Smokers have decreased levels of MAO B
  and abnormally high levels of dopamine, which may
  encourage the smoker to seek the pleasure of more
  tobacco smoke.

27
Innocent Bystander

• the effect of tobacco smoke on nonsmokers who
  must share the same environment with a smoker.
  The United States Environmental Protection Agency
  (EPA) estimates that exposure to ETS, which
  contains all the toxic agents inhaled by a
  smoker, causes 3,000 cancer deaths and an
  estimated 40,000 deaths from heart disease per
  year in nonsmokers. Secondhand smoke can
  aggravate asthma, pneumonia, bronchitis, and
  impaired blood circulation.

28
(No Transcript)
29
References

• Jack Brown M.S. Biology
• Shier,David, Jackie Butler, Ricki Lewis Holes
  Human Anatomy and Physiology 10th edition 2004
  McGraw-Hill
• Marieb, Elaine Essentials of Human Anatomy and
  Physiology 7th edition. 2003 Pearson Education
  Inc Benjamin Cummings pub.
• Microsoft Encarta Encyclopedia 2004
• Starr and Taggart The Unity and Diversity of
  Life 10th edition 2004 Thomson Brookes/Cole
• Campbell and Reece Biology 6th edition 2002
  Benjamin Cummings.
• Raven and Johnson Holt Biology 2004 Holt,
  Rinehart and Winston.