RespirationRespiration. Learning Objectives (a) identify on diagrams and name the larynx, trachea, bronchi, bronchioles, alveoli and associated capillaries

RespirationRespirationRespirationRespiration

Learning Objectives• (a) identify on diagrams and name the larynx, trachea,

bronchi, bronchioles, alveoli and associated capillaries • (b) state the characteristics of, and describe the role of,

the exchange surface of the alveoli in gaseous exchange

• (c) describe the removal of carbon dioxide from the lungs, including the role of the carbonic anhydrase enzyme

• (d) describe the role of cilia, diaphragm, ribs and intercostal muscles in breathing

• (e) describe the effect of tobacco smoke and its major toxic components - nicotine, tar and carbon monoxide, on health

• (f) define and state the equation, in words and symbols, for aerobic respiration in human

• (g) define and state the equation, in words only, for anaerobic respiration in human

Why do living organisms respire?

• Need energy to move, excrete, grow, reproduce and maintain themselves.

• Food contains chemical energy.• Respiration is the release of this

energy when food (glucose) is broken down in living cells.

Respiration

• The oxidation of food substances with the release of energy in living cells.

Aerobic RespirationAerobic RespirationAerobic RespirationAerobic Respiration

Aerobic Respiration

• Breakdown of glucose in the presence of oxygen with the release of relatively large amount of energy.

• Carbon dioxide and water are released as waste products.

• Enzymes catalysed the reactions in the mitochondria.

+ 2898 kJ

What is the energy used for?

1. Cell division and growth2. Synthesis of proteins, fats and vitamins3. Transmission of nerve impulses4. Maintenance of a constant body

temperature5. Active transport in the absorpton of

food substances by the small intestine6. Muscular contractions e.g. heartbeat &

respiratory movements.

Anaerobic RespirationAnaerobic RespirationAnaerobic RespirationAnaerobic Respiration

Anaerobic Respiration• Breakdown of glucose in the

absence of oxygen to release energy.

• Can take place in yeast as well as the muscles.

Yeast• Respires anaerobically when oxygen is

absent.• Little energy is released.• Yeast cannot be very active under

such situations.• Alcoholic fermentation

+ 210 kJ

Anaerobic Respiration (Muscles)

• Muscle cells normally respire aerobically.

• Carry out anaerobic respiration when there is a shortage of oxygen.

Differences Aerobic

Respiration• Uses oxygen• No alcohol or

lactic acid made• Large amount of

energy released

• CO2 always released

Anaerobic Respiration

• Do not use oxygen• Alcohol or lactic

acid made• Small amount of

energy released

• CO2 sometimes released

What happens during exercise?

• Vigorous muscular contraction --> muscles first use oxygen to respire. (aerobic)

• Panting --> to remove carbon dioxide and take in more oxygen.

• Heart beats faster so that more oxygen can be brought to the muscles.

• LIMIT to the rate of breathing and heartbeat. They CANNOT keep on increasing.

• To continue vigorous exercise, more energy needs to be released.

• Muscle cells carry out ANAEROBIC respiration.

• Lactic acid is produced.GLUCOSE ------> Lactic acid

+small amount of energyC6H12O6 ---- 2CH3CH(OH)COOH + 150 kJ

• Lactic acid slowly builds up in the muscles.

• Muscle has an “OXYGEN DEBT”.• Lactic acid cause fatigue• Body needs to rest & recover• Muscular pain is due to the lactic

acid.

What happens during RESTING?

• Lactic acid is removed from the muscles and transported to the liver.

• Some of the lactic acid is oxidized to energy.• Converts remaining lactic acid into glucose

Lactic acid ---------------------> Energy(muscles) remaining ------------------->

glucose lactic acid

muscle

Oxidized

How do we know organisms respire?

1. To find out whether carbon dioxide is given off during respiration

2. To find out if carbon dioxide is given off during fermentation

3. To find out if heat is released during respiration

Gaseous exchange Gaseous exchange Gaseous exchange Gaseous exchange

Gaseous exchange• Process of the

transfer of oxygen from the air to the cells and the transfer of carbon dioxide and water from the cells back to the surroundings.

Tissue RespirationTissue RespirationTissue RespirationTissue Respiration

Tissue Respiration• Oxidation of food with the release

of energy.• Occurs within the cell or tissues

(internal respiration)

Gaseous Exchange in ManGaseous Exchange in Man

The Structure of the Respiratory System

• The organs involved are:2 lungs in the thorax;The air passages leading to them.

• Each lung is filled with many tiny air sacs called alveoli, where oxygen diffuses into the blood.

The Air Passage Way

• Consist of:the nasal passages/cavity, pharynx, larynx, trachea, bronchi & bronchioles.

• Air enters by 2 external nostrils --- 2 nasal passages --- 2 internal nostrils --- pharynx --- larynx --- trachea (via glottis) --- bronchi --- bronchioles --- alveoli.

Path of Air Through the Respiratory SystemPath of Air Through the Respiratory System

atmosphere

atmosphere

external nostril

external nostril

atmosphere

external nostril

nasal passages external nostril

nasal passages

atmosphere

external nostril

nasal passages

pharynx

external nostrilpharynx

nasal passages

atmosphere

external nostril

nasal passages

pharynx

larynx

external nostril

larynx

pharynxnasal passages

atmosphere

external nostril

nasal passages

pharynx

larynx

trachea

external nostril

trachealarynx

pharynxnasal passages

atmosphere

external nostril

nasal passages

pharynx

larynx

trachea

bronchi

external nostril

trachealarynx

pharynx

bronchi

nasal passages

atmosphere

external nostril

nasal passages

pharynx

larynx

trachea

bronchi

bronchioles

external nostril

trachealarynx

pharynx

bronchi

bronchioles

nasal passages

atmosphere

external nostril

nasal passages

pharynx

larynx

trachea

bronchi

bronchioles

alveoli

external nostril

trachealarynx

pharynx

bronchi

bronchioles

cluster of alveoli (air sacs)

nasal passages

The Air Passage Way

The Nose

• Air enters through two external nostrils (nares)

• Nasal passages lined with hairs and moist mucous membrane

• Trap dust & foreign particles, including bacteria.

• Air is warmed and moistened;• Detect harmful chemicals (by

sensory cells).

The Trachea• lies in front of esophagus• supported by C-shaped rings of

cartilage (which ensure it is always kept opened)

• Epithelium has gland cells to secrete mucus which traps dust particles

• bears cilia to sweep dust particles upwards into pharynx

Lining of Trachea

Gland cell

nucleus

The Lungs• Each lung lies in the pleural cavity.• The pleural cavity is lined by 2

transparent pleural membranes • Inner pleuron covers the lungs• Outer pleuron in contact with

thoracic wall and diaphragm• The pleural fluid helps to reduce

friction on the lungs when they rub against the rib cage during inspiration.

• The lower end of the trachea divides into 2 bronchi (singular: bronchus), one to each lung.

• Within the lungs, the bronchial tubes divide into smaller tubes – the bronchioles (*NO cartilage).

• Each bronchiole ends with many air sacs called alveoli.

A cluster of alveoli

• Alveoli provide a large surface area (100 m2)

• The wall of alveolus is very thin. Only one cell thick. Allows easy diffusion of O2 & CO2

Adaptations of lungs for efficient gaseous

exchange

• A thin film of moisture covers the surface of the alveolus. O2 dissolves in this liquid before diffusing across the wall of the alveolus.

• The walls of the alveoli are richly supplied with blood capillaries. The flow of blood maintains the concentration gradient of gases.

The Chest cavity• Chest wall is supported by ribs• Two sets of intercostal muscles

(internal and external) control the movement of the ribs

• The diaphragm separates the thorax from the abdomen

• The intercostal muscles and the diaphragm contract and relax, causing the volume of thoracic cavity to change

Mechanism of BreathingMechanism of Breathing

rib

sternum

vertebral column

Front view Side view

When you breathe in or inspire, the following events take place:

Movement of rib cage during inspiration

rib cage

rib

sternum

vertebral column


• Your diaphragm contracts and flattens.


diaphragm contracts and flattens

rib cage

rib

sternum

vertebral column


• Your external intercostal muscles contract while your internal intercostal muscles relax.


rib cage


ribs and sternum raised

rib

sternum

vertebral column


Ribs swing up

• Your ribs move upwards and outwards. Your sternum also moves up and forward.


rib cage




rib

sternum

vertebral column


Ribs swing up and increase volume of thorax

• The volume of your thoracic cavity increases.


rib cage



volume of thorax increases


rib

sternum

vertebral column

Front view


• Air pressure in your lungs causes them to expand to fill up the enlarged space in your thorax.

Movement of rib cage during inspirationSide view

rib cage



volume of thorax increases and lungs expand


rib

sternum

vertebral column



• Expansion of your lungs causes the air pressure inside them to decrease.

Movement of rib cage during inspirationSide view

rib cage



lungs expand, causing air pressure inside lungs to decrease


rib

sternum

vertebral column

Front view


• Atmospheric pressure is now higher than the pressure within your lungs. This causes air to rush into your lungs.


rib cage



lungs expand, causing air pressure inside lungs to decrease

air enters lungs

Side viewSide view

When you breathe out or expire, the following events take place:

rib

sternum

vertebral column

Side viewFront viewMovement of rib cage during expiration

rib cage

• Your diaphragm relaxes and arches upwards.

rib

sternum

vertebral column


rib cage diaphragm relaxes and arches upwards

• Your internal intercostal muscles contract while your external intercostal muscles relax.

rib

sternum

vertebral column




rib

sternum

vertebral column

Ribs swing down

• Your ribs move downwards and inwards. Your sternum also moves down to its original position.

Front viewMovement of rib cage during expiration

Side view


ribs and sternum returned to original position


rib

sternum

vertebral column

Ribs swing down and decrease volume of thorax

• The volume of your thoracic cavity decreases.

volume of thorax decreases


Side view




rib

sternum

vertebral column


• Your lungs are compressed and air pressure inside them increases as the volume decreases.


lungs are compressed, causing air pressure inside lungs to increase

Side view




rib

sternum

vertebral column

Front view


Movement of rib cage during expiration

• Air pressure within the lungs is now higher than atmospheric pressure. The air is forced out of your lungs to the exterior.

lungs are compressed, causing air pressure inside lungs to increase

Side view


air expelled from lungs

When you inhale, you…

Relax your Internal intercostal muscles and Contract your External intercostal muscles

R

IC

E

Inhalation

E

R

I

C

Exhalation

When you exhale, your…

External intercostal muscles Relax and your Internal intercostal muscles Contract

Gaseous exchange in alveoli

Oxygen• Alveolar air contains higher

concentration of oxygen than the blood.• Oxygen dissolves in the moisture lining

and diffuses into the blood capillaries.• Oxygen combines with haemoglobin to

form oxyhaemoglobin.

Carbon dioxide• Tissue cells produce carbon dioxide during

aerobic respiration.• Carbon dioxide diffuses into the blood and

enters red blood cells.• Carbon dioxide reacts with water to form

carbonic acid catalysed by carbonic anhydrase.

• Carbonic acid converted into hydrogencarbonate ions which diffuse out of the red blood cells into the plasma.

In the lungs• Hydrogencarbonate ions diffuse

back into the red blood cells• Converted into carbonic acid and

then into water and carbon dioxide• Carbon dioxide diffuses out of

blood capillaries into the alveoli and out of the lungs

How diffusion gradient is maintained?

• Continuous supply of blood through the capillary networks

• Continuous breathing of air in and out of the alveoli

Differences between inspired air and expired air

Component Inspired air Expired air

Oxygen 21% 16.4%

Carbon dioxide

0.03% 4.0%

Nitrogen 78% 78%

Water vapour Variable Saturated

Temperature Variable 370C

Dust particles Variable but usually presnet

little

Lung CapacityResidual air (1500 cm3)• Air that is left behindTidal air (500cm3)• Air that enters and leaves the lungs in each

breathing cycleComplemental air (1500cm3)• Additional air that can be taken inSupplemental air (1500cm3)• Additional air that can be forced outVital capacity (3500-4000cm3)=tidal air + complemental air + supplemental air

Lung Capacity

Stimulus for breathing• High concentration of carbon

dioxide in the blood or alveolar air

• Hyperventilation or overbreahting can cause death as no breathing occurs when there is no carbon dioxide in the lungs

Tobacco smoke• Nicotine• Carbon monoxide• Tar• irritants

Effects of Tobacco smoke on human

healthBronchitis• Redness and swelling of the lining of

air passages• Destruction of the cilia• Dust and harmful chemicals are able to

move past the bronchi and invade the alveoli

• Air passages become irritated and clogged with mucus and dust

• Lots of phlegm and coughing

Asthma

• Irritants cause allergic reactions in the respiratory tract

• Constriction of the respiratory tract

• Suffocation and death

Emphysema• Violent coughing breaks partition

walls between air sacs• Alveolar sacs may become less

elastic• Decrease surface area for gaseous

exchange• Lungs become inflated with air• Difficulty in breathing, wheezing

Lung cancer• Carcinogenic compound,

benzopyrene causes cancer cells to be produced

• Tar and resin promote proliferation of these cancer cells

• Shortness of breath • Coughing up of mucus and blodd

Tar• Contains cancer-causing

(carcinogenic) chemicals which induce uncontrolled cell division of the epithelium

• Paralyses cilia lining the air passages

Heart disease• Nicotine stimulates release of

adrenaline• Increases blood pressure and

heart rate• Increases chance of blood clot and

plaque deposit on the walls of coronary arteries

• Heart attacks and death

Smoking during Pregnancy

• Restricts blood vessels reducing amount of nutrients and oxygen to baby

• Low birth weight of baby• Prone to illness• Increase potential for birth defects and

abnormalities• Increased chances of a miscarriage• Increased chances of a premature birth• Has a greater risk of baby being born

dead

April 20, 2023

Respiration (Concept Map)Respiration (Concept Map)

RESPIRATION

• Occurs in living cells.

• Enzymes are involved.• Oxidation of food substances with the release of energy.

April 20, 2023Copyright © 2006-2011 Marshall Cavendish International (Singapore) Pte. Ltd. 84

Aerobic Respiration

RESPIRATION




Aerobic RespirationAnaerobic

Respiration

RESPIRATION





Respiration

RESPIRATION

• Oxygen is required.

• Large amount of energy is released.

• Carbon dioxide and water are produced.





Respiration

RESPIRATION




• Oxygen is not required.

• Small amount of energy is released.

• Lactic acid is produced in mammals. Ethanol and carbon dioxide are produced in yeast.





Respiration

RESPIRATION







Differences





Respiration

RESPIRATION

Breathing mechanism







Differences





Respiration

How the body takes in oxygen and removes carbon dioxide

RESPIRATION

Breathing mechanism







Differences





Respiration


RESPIRATION

Breathing mechanism







Differences





Respiration


RESPIRATION

Breathing mechanism







Differences




Inspiration• External intercostal muscles contract, internal intercostal muscles relax.

• Ribs move upwards and outwards.

• Diaphragm contracts and flattens.

• Volume of thorax increases.

• Air pressure in thorax decreases.

• Air flows into the lungs.


Respiration


RESPIRATION

Breathing mechanism







Differences










Expiration• External intercostal muscles relax, internal intercostal muscles contract.

• Ribs move downwards and inwards.

• Diaphragm relaxes and arches upwards.

• Volume of thorax decreases.

• Air pressure in thorax increases.

• Air flows out of the lungs.


Respiration


RESPIRATION

Breathing mechanism







Differences










Expiration• External intercostal muscles relax, internal intercostal muscles contract.

• Ribs move downwards and inwards.

• Diaphragm relaxes and arches upwards.

• Volume of thorax decreases.

• Air pressure in thorax increases.

• Air flows out of the lungs.

Gaseous exchange• Oxygen dissolves in film of moisture covering alveolar wall.

• Dissolve oxygen diffuses into blood capillaries.

• Carbon dioxide diffuses from blood into alveolar cavity.

Documents

RespirationRespiration. Learning Objectives (a) identify on diagrams and name the larynx, trachea, bronchi, bronchioles, alveoli and associated capillaries