BREATHING AND
EXCHANGE OF GASES
VIKASANA - VIGNANA PATHADEDEGE NIMMA NADIGE
Bridge Course Program for SSLC Students who want to take up Science in I PUC in 2012
CONTENTS
INTRODUCTION
DEFINiTION OF RESPIRATION
TYPES OF RESPIRATION
RESPIRATORY ORGANS
BREATHING
MECHANISM OF BREATHING
TERMINOLOGIES
EXCHANGE OF GASES
TRANSPORT OF GASES
INTRODUCTION
THE BASIC NEEDS OF LIVING
ORGANISMS.
AIR
WATER
FOOD
ONLY LIVING BEING RESPIRES
DEFINITION
OXIDATION OF FOOD MATERIAL AT
CELLULAR LEVEL BY USING MOLECULAR
OXYGEN TO RELEASE BIOLOGICAL ENERGY
AND BY-PRODUCTS LIKE METABOLIC
WATER AND CARBON- DI-OXIDE.
EQUATION:
C6H1206 + 602 6CO2↑ + 6H2O↑ + 673KCAL
TYPES OF RESPIRATION:
BASED ON AVAILABILITY OF OXYGEN
AEROBIC RESPIRATION
(AS EXPLAINED ABOVE)
ANAEROBIC RESPIRATION
C 6 H 12O6
ANAEROBIC RESPIRATION
DEFINITION:
INCOMPLETE OXIDATION OF FOOD
MATERIAL (IN THE ABSENCE OF O2)
PRODUCES ETHYL ALCOHOL OR
ORGANIC ACID, CO2 AND SMALL
AMOUNT OF ENERGY.
C6H12O6 2C2H5OH + 2CO2 ↑ + 2ATP
BASED ON REPIRATORY ORGAN
1. DIRECT RESPIRATION
2. INDIRECT RESPIRATION
DIRECT RESPIRATION:
SINGLE-CELLED ORGANISMS EXCHANGE
GASES DIRECTLY ACROSS THEIR CELL
MEMBRANE. HOWEVER, THE
SLOW DIFFUSION RATE OF OXYGEN
RELATIVE TO CARBON DIOXIDE LIMITS THE
SIZE OF SINGLE-CELLED ORGANISMS.
SPONGES AND JELLYFISH LACK
SPECIALIZED ORGANS FOR GAS EXCHANGE
AND TAKE IN GASES DIRECTLY FROM THE
SURROUNDING WATER.
TRACHEAL SYSTEMS:
MANY TERRESTRIAL ANIMALS HAVE THEIR
RESPIRATORY SURFACES INSIDE THE BODY
AND CONNECTED TO THE OUTSIDE BY A
SERIES OF TUBES. TRACHEAE ARE THESE
TUBES THAT CARRY AIR DIRECTLY TO CELLS
FOR GAS EXCHANGE
.
VIKASANA - VIGNANA PATHADEDEGE NIMMA NADIGE
Bridge Course Program for SSLC Students who want to take up Science in I PUC in
2012
INDIRECT RESPIRATION
ORGANISMS HAVE WELL DEVELOPED
RESPIRATORY ORGANS LIKE
GILLS (FISHES),
SKIN (AMPHIBIANS),
LUNGS (REPTILES, AVES, MAMMALS)
BREATHING
EXT ENV
̈
TRASNSPORT OF GASES
RO
CELL.
BREATHING IN HUMAN
THIS SYSTEM INCLUDES INHALE
AND EXHALE. EXTERNAL AIR ENTER THE
LUNGS & MOVES OUT.
AIR ENTERS THE BODY THROUGH THE
NOSE, IS WARMED, FILTERED AND
PASSED THROUGH THE NASAL CAVITY.
.
AIR PASSES THE PHARYNX (WHICH HAS
THE EPIGLOTTIS THAT PREVENTS FOOD
FROM ENTERING THE TRACHEA).
THE UPPER PART OF THE TRACHEA
CONTAINS THE LARYNX (VOCAL CORD) .
AFTER PASSING THE LARYNX, THE AIR
MOVES INTO THE BRONCHI THAT CARRY
AIR IN AND OUT OF THE LUNGS.
MECHANISM OF BREATHING
INSPIRATION
INTERCOSTAL MUSCLES CONTRACT,
DIAPHRAGM CONTRACTS AND
BECOMES FLAT, RIBS MOVES UPWARD
AND OUTWARD EXPANDING VOLUME OF
CHEST, LOWERING PRESSURE IN
LUNGS, AIR MOVES INSIDE.
EXPIRATION
INTERCOSTAL MUSCLES RELAX,
DIAPHRAGM RELAX & RESUMES
DOME SHAPE, RIBS MOVES
DOWNWARD AND INWARD
RESULTING IN REDUCING THE SPACE,
INCREASE IN THE PRESSURE
EXPULSION OF AIR FROM LUNGS
Inspired and Expired Air Comparison
Gas Inspired Air Expired Air Alteration
N
78%
76%
No real change.
O2
20.8%
15.3%
Reduced by about a
quarter
CO2
0.04%
4.2%
Increased by about a
hundred and five times
6.1%
Increased about five times
Water
1.2%
Vapour
Note: a lot of water is lost from the body each day due to breathing.
SPIROMETER & RESPIRATORY
VOLUME
SPIROMETER OR RESPIROMETER IS
AN INSTRUMENT TO MEASURE
VOLUME OF AIR DURING BREATHING.
THE GRAPHIC RECORD DURING
BREATHING IS CALLED SPIROGRAM.
TIDAL VOLUME (TV)
THE VOLUME OF AIR ENTERING
OR LEAVING THE LUNGS DURING
NORMAL BREATHING AT REST IS
CALLED TIDAL VOLUME. THIS IS
USUALLY 500mL IN BOTH MALES AND
FEMALES.
INSPIRATORY RESERVE VOLUME (IRV) :THE ADDITIONAL AIR THAT IS
INHALED AFTER TIDAL VOLUME BY
TAKING A VERY DEEP BREATH IS
CALLED INSPIRATORY RESERVE
VOLUME. THIS IS USUALLY ABOUT
3 LITRE IN MALES 1.9 LITRE IN
FEMALE.
EXPIRATORY RESERVE VOLUME (ERV)
THE ADDITIONAL AIR THAT CAN
BE EXHALED BEYOND A TIDAL
VOLUME BY EXERTING MAXIMUM
FORCE POSSIBLE IS CALLED ERV. THIS
IS USUALLY 1 LITRE IN MALES AND 0.7
LITRE IN FEMALES
RESIDUAL VOLUME (RV)
THE VOLUME OF AIR WHICH REMAINS
STILL IN THE LUNG AFTER THE MOST
FORCEFUL EXPIRATION IS CALLED
RESIDUAL VOLUME. IT IS ABOUT 1.2
LITRE IN MALES AND 1.1 LITRE IN
FEMALES.
THE COMBINATIONS OF LUNG VOLUMES
ARE CALLED PULMONARY
CAPACITIES. THEY ARE,
INSPIRATION CAPACITY
THIS IS THE TOTAL INSPIRATORY ABILITY
OF LUNGS. IT IS THE SUM TOTAL OF TV
& IRV (IN MALES IT IS ABOUT 3.5L &
FEMALES 2.4L)
EXPIRATORY CAPACITY
THE TOTAL VOLUME OF AIR A PERSON
CAN EXPIRE AFTER A NORMAL
EXPIRATION IS CALLED EC. IT IS ABOUT
1.5mL.
FUNCITIONAL RESIDUAL CAPACITY (FRC)
THE VOLUME OF AIR THAT REMAINS IN
THE LUNGS AFTER NORMAL
EXPIRATION. THIS IS SUM TOTAL OF
ERV & RV (IT IS ABOUT 2.2L IN MALES
AND 1.8L IN FEMALES).
VITAL CAPACITY(VC)
THIS IS MAXIMUM VOLUME OF AIR
A PERSON CAN EXPEL FROM LUNGS.
IT IS THE SUM TOTAL OF IRV, TV &
ERV. (IN MALES IT IS ABOUT 4.5L & IN
FEMALES ABOUT 3.1L)
TOTAL LUNG CAPACITY (TLC)
THE MAXIMUM VOLUME TO WHICH
THE LUNGS CAN BE EXPANDED WITH
GREATEST FORCE. THIS IS THE SUM
TOTAL OF VITAL CAPACITY & RESIDUAL
VOLUME. (IN MALES IT IS ABOUT 5.7L &
IN FEMALES ABOUT 4.2L)
MEASUREMENT OF LUNG CAPACITY
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