respiration - wikispaces · pdf file4 respiration • definition – release of energy...

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RESPIRATIONRESPIRATION

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Lesson 1Learning Objective1.Name and state uses of energy in the human body.2.Define respiration, aerobic respiration and anaerobic respiration and state

the equations.3.Describe the effect of lactic acid production in muscles during exercise.4.Describe oxygen debt.5.Describe oxidation of lactic acid.Outline Uses of energy Respiration Aerobic respiration Anaerobic respiration

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Why do humans respire?

• To produce energy• There are many uses of energy.

– All processes of 'staying alive'.– Muscle contraction– Protein synthesis– Cell division– Active transport– Growth – Reproduction – Transmission of nervous impulses– Maintenance of constant body temperature

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Respiration

• Definition– Release of energy from food substances in all

living cells• 2 types of respiration

– Aerobic– Anaerobic

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Aerobic Respiration

• Definition– Breakdown of glucose in the presence of oxygen with the

release of relatively large amount of energy

• Equation

C6H12O6 + 6O2 energy + 6CO2 + 6H2O

F o o d + o x y g e n e n e r g y + c a r b o n d io x id e + w a te r

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• The energy released from glucose in respiration is in the form of adenosine triphosphate (ATP).

• This respiration takes place in the mitochondria (found in the cytoplasm)

glucose carbon dioxide waste productswhich the body

+ respiration water gets rid of

oxygen energy whichis used

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Anaerobic Respiration

• Definition– Breakdown of glucose in the absence of

oxygen with the release of relatively small amount of energy

• It can take place in yeast and in human muscle.

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Anaerobic (Yeast)• Respires anaerobically in the absence of

oxygen.• Releases little energy.• Alcohol is produced.• This process is called fermentation and it is used

in the brewing of alcoholic drinks.

glucose ethanol + carbon dioxide + energy

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Anaerobic (Muscle)

• Muscle cells normally respire aerobically.

• However, when there is shortage of oxygen, they respire anaerobically.

Glucose Lactic acid + Small energy

C6H12O6 2 CH3CH(OH)COOH + 150 kJ

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Respiration during exercise

• Exercising requires energy.• When we do vigorous exercise, our

muscles need more energy than can be supplied by aerobic respiration.

• The extra energy needed comes from anaerobic respiration.

• This produces lactic acid.Glucose Lactic acid + Small energy

C6H12O6 2 CH3CH(OH)COOH + 150 kJ

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Lactic Acid• Lactic acid is produced when anaerobic respiration

occurs in human muscles.• Accumulation of lactic acid causes fatigue and muscular

pain. It forces the body to rest and recover.• During anaerobic respiration, human muscles lack

oxygen and is said to have an 'oxygen debt'.• This 'oxygen debt' need to be 'repaid' once oxygen is

available again. The oxygen is then used to remove lactic acid by oxidising it.

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Exercise

1.Create a table to show the differences between aerobic and anaerobic respiration

2.Describe how lactic acid is removed to produce glucose.

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Lesson 2Learning Objective1.Identify on diagrams and name the larynx, trachea, bronchi,

bronchioles, alveoli and associated capillaries.2.Describe the role of cilia and goblet cells.3.State the characteristics of alveoli and describe the role of exchange

surface of alveoli in gas exchange.

Outline How do we know organisms respire? The gaseous exchange system

– Air pathways

– Structures and functions

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How do we know if organisms respire?

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To show respiration in an animal

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To find out whether carbon dioxide is given off during respiration

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To find out whether carbon dioxide is given off during respiration

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To find out whether carbon dioxide is given off during fermentation

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Gaseous Exchange• Gaseous exchange is the

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.

• This process is carried out efficiently by diffusion through the cell surface membrane.

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Gaseous Exchange System

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atmosphere

Air pathway

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atmosphere

external nostril

external nostril

Air pathway

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atmosphere

external nostril

nasal passages external nostril

nasal passages

Air pathway

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atmosphere

external nostril

nasal passages

pharynx

external nostrilpharynx

nasal passages

Air pathway

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atmosphere

external nostril

nasal passages

pharynx

larynx

external nostril

larynx

pharynxnasal passages

Air pathway

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atmosphere

external nostril

nasal passages

pharynx

larynx

trachea

external nostril

trachealarynx

pharynxnasal passages

Air pathway

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atmosphere

external nostril

nasal passages

pharynx

larynx

trachea

bronchi

external nostril

trachealarynx

pharynx

bronchi

nasal passages

Air pathway

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atmosphere

external nostril

nasal passages

pharynx

larynx

trachea

bronchi

bronchioles

external nostril

trachealarynx

pharynx

bronchi

bronchioles

nasal passages

Air pathway

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atmosphere

external nostril

nasal passages

pharynx

larynx

trachea

bronchi

bronchioles

alveoli

external nostril

trachealarynx

pharynx

bronchi

bronchioles

cluster of alveoli (air sacs)

nasal passages

Air pathway

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Nose cavity: the air is moistened and warmed in here. Dirt and dust are trapped in mucus which covers the walls of the cavity.

Hard palate: the “roof” of your mouth. This lets you chew and breathe at the same time

Epiglotis: this opens to let air go into your lungs. It closes when you swallow food.

wind pipe (Trachea)

air

Mucus moving towards your oesophagus

Soft palate: this opens to let air through. When you swallow, it closes the back of your nose cavity.

Oesophagus : food goes down here to your stomach

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The Nose

• Air enters through two external nostrils (nares)

• Nasal passages are lined with hairs and moist mucous membrane.

• Advantages of breathing through nose:– Hairs trap dust and foreign particles, including bacteria– Air is warmed and moistened– Sensory cells in mucous membrane may detect

harmful chemical and produces mucus.

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The Trachea

• Lies infront of the oesophagus.• It has

– C-shaped rings of cartilage to support and ensure it is always kept open.

– Gland cells/Goblet cells in the epithelium to secrete mucus which traps dust particles

– Cilia to sweep dust particles upwards into pharynx.

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Gland cell

Nucleus

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The Lungs

• Each lung lies in the pleural cavity.• The pleural cavity is lined with 2 transparent

pleural membranes– Inner pleuron – covers the lungs– Outer pleuron – in contact with thoracic wall and

diaphragm• The pleural fluid

– Between the pleura– Helps to reduce friction on the lungs during

inspiration.

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Exercise

Explain how the nose and trachea help in preventing the entry of dust into the lungs. (4)

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Lesson 3Learning Objective1.State the characteristics of alveoli and describe the

role of exchange surface of alveoli in gas exchange.

Outline The alveoli

– Characteristics– Gas exchange

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The Alveoli (singular: alveolus)

• 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.

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• Alveoli is where gaseous exchange takes place.

• Characteristics:– Large surface area because the alveoli are

folded inwards.– Thin membrane walls (one cell thick) so that

gases can diffuse through them quickly.– A thin film of moisture covering the surface so

that oxygen can dissolve before diffusing through the membrane.

– Close contact with the blood supply (capillary)

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Gaseous exchange in alveoli

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4.Part of your pulmonary vein. The blood now has a lot of oxygen in it but not much carbon dioxide.

1. Part of your pulmonary artery. The blood has not much oxygen in it but a lot of carbon dioxide.

2. carbon dioxide diffuses through your blood into the alveoli of the air sac.

3. Oxygen diffuses from the air into your blood

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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.

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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.

This reaction is catalysed by carbonic anhydrase.• Carbonic acid breaks down into hydrogencarbonate ions

which diffuse out of the red blood cells into the plasma.

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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

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Exercise

What is the function of alveoli and how are they adapted to carry this function? (5)

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Lesson 4Learning Objective1.Describe the mechanisms of breathing and

understand the changes in lung volume and pressure during breathing.

Outline Breathing mechanism

– Inhalation– Exhalation

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Chest (Thoracic) CavityDuring breathing, the lungs are inflated and deflated by the action of muscles. They are ...– Intercostal muscles (between the ribs)

• Internal intercostal and external intercostal– Control the movement of ribs

– Diaphragm (a sheet of muscle lying below the lungs, separating them from the abdomen)

The intercostal muscles and the diaphragm contract and relax, causing the volume of chest cavity to change.– Also changes the pressure within.

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Intercostal muscles & Diaphragm

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Breathing Mechanism

What happen to..– the lungs (volume and pressure)– the rib cage (from the action of intercostal

muscles)– the diaphragm

during– expiration (breathe out/exhalation)– inspiration (breathe in/inhalation)

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During Inspiration

rib

sternum

vertebral column

Front view Side view

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

rib cage

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rib

sternum

vertebral column


Your diaphragm contracts and flattens.

diaphragm contracts and flattens

rib cage

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rib

sternum

vertebral column


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

rib cage


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ribs and sternum raised

rib

sternum

vertebral column


Ribs swing up

Your ribs move upwards and outwards.

rib cage



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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

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rib

sternum

vertebral column

Front view


Air pressure in your lungs causes them to expand.

Side view

rib cage



volume of thorax increases and lungs expand

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rib

sternum

vertebral column



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

Side view

rib cage



lungs expand, causing air pressure inside lungs to decrease

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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

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

rib

sternum

vertebral column

Side viewFront view

rib cage

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Your diaphragm relaxes and arches upwards.

rib

sternum

vertebral column

Side viewFront view

rib cage diaphragm relaxes and arches upwards

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

rib

sternum

vertebral column

Side viewFront view


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rib

sternum

vertebral column

Ribs swing down

Your ribs move downwards and inwards.



ribs and sternum returned to original position

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rib

sternum

vertebral column

Ribs swing down and decrease volume of thorax

The volume of your thoracic cavity decreases.

volume of thorax decreases




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rib

sternum

vertebral column


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

Front view

lungs are compressed, causing air pressure inside lungs to increase

Side view



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rib

sternum

vertebral column

Front view


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

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Inhalation & Exhalation

When you inhale, you…

Relax your

Internal intercostal muscles and

Contract your

External intercostal muscles

R

ICE

Inhalation

ERIC

ExhalationWhen you exhale, your…

External intercostal muscles Relax and your

Internal intercostal muscles Contract

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Breathing MechanismFill in the blanks.

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Lesson 5Learning Objective

1. Tabulate the composition of inspired and expired air.2. Understand the differences in composition.3. Describe the effects of respiratory diseases on the process

of gas exchange – bronchitis, emphysema, lung cancer.

Outline Composition of inspired and expired air. Respiratory diseases

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Inspired vs. Expired AirComponent 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 Little

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Bronchitis

• Bronchitis is an inflammation of the airway.

• Causes– Tar – paralyses the cilia

• Effect– 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

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Emphysema

• Causes– Violent coughing causing alveolar walls to

become stretched and lose their elasticity.– Alveolar walls become weak, causing them to

break down.• Effects

– Decrease surface area for gaseous exchange– Lungs become inflated with air– Difficulty in breathing, wheezing

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Asthma

• Air obstruction characterised by narrowing of air passages.

• Causes– Environmental or genetic

• Allergic reactions in the respiratory tract due to irritants

• Effect– Constriction of the respiratory tract– Suffocation and death

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Lung Cancer• Uncontrollable cell growth in lungs.• Causes

– Carcinogenic compound in tar, damages the cells lining the lungs and causes cancer cells to be produced

• Effects– Shortness of breath– Coughing up of

mucus and blood

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Smoking

• Smoking is the leading cause of lung disease.

• Contents of tobacco smoke– Nicotine– Tar– Carbon monoxide

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Nicotine• Addictive drug that stimulates release of

adrenaline– Increases blood pressure and heart rate– Increases chance of blood clot and plaque

deposit on the walls of coronary arteries– Affects gaseous exchange between alveoli

and blood capillaries

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Tar

• Tar is absorbed by cells in the lungs, especially cells lining the bronchi and bronchioles.

• Normally, these cells form a thin, protective layer. But the tar makes them divide and build up into a thicker layer.

• This may lead into cancer.

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• Tar is also an irritant. – It makes the linings of the respiratory passages

inflamed, causing chronic bronchitis.– It paralyses the cilia and cause extra mucus to be

made by goblet cells.–This mucus trickles down into the lungs–Bacteria breed in the mucus, causing infection. –Coughing moves the mucus upwards.–Constant coughing can damage the delicate

alveoli.–This makes it difficult for the person to get enough

oxygen into their blood.–They have emphysema.

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Carbon Monoxide

• Carbon monoxide is absorbed into the blood.

• It combines rapidly with haemoglobin in the red blood cells.

• This means there is less haemoglobin available to carry oxygen.

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The difference between respiration, gaseous exchange and breathing

• Respiration is the release of energy from food substances in all living cells.

• Gaseous exchange is the exchange of gases across a surface.

• Breathing (ventilation) is muscular movements which keep the gaseous exchange surface supplied with oxygen.

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Aerobic Respiration Anaerobic Respiration

How the body takes in oxygen and removes carbon dioxide

RESPIRATION

Breathing mechanism

• Oxygen is required.• Large amount of energy is released.• Carbon dioxide and water are produced.

• Oxygen is not required.• Small amount of energy is released.• Lactic acid is produced in mammals. Ethanol and carbon dioxide are produced in yeast.

Differences

• Occurs in living cells.• Enzymes are involved.

• Oxidation of food substances with the release of energy.

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.

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.

respiration - wikispaces · pdf file4 respiration • definition – release of energy...

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