Hasimah Azit

Respiration Overview

EXTERNAL

INTERNAL

TRANSPORTATION

ENERGY REQUIREMENT

FOR:• Muscle contraction• Active transport• Transmission of nerves• Formation of new organelle• Cell division• Maintain body temperature

Cellular respiration is the process in which energy-rich molecules such as glucose are converted into energy usable for life processes

• The process occurs in gradual steps that result in the conversion of the energy stored in glucose to usable chemical energy in the form of ATP

• Waste products (CO2 + H2O) are released through exhaled air, sweat and urine

Cellular respiration

Substrate for energy production:

Glucose – obtain from food

Oxygen - from air

– Aerobic respiration

– Anaerobic respiration

Aerobic respiration

• Aerobic respiration requires oxygen in order to generate energy.

• 36 ATP molecules can be made per glucose

• reactions take place in the mitochondria

mitochondria

Chemical equation:

C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy released (2898 kJ/mol)

glucose + oxygen carbon dioxide + water + E

• Activities like sprinting require levels of energy that are greater than the body can produce with the aerobic (with oxygen) metabolism.

• For these activities, the body relies on anaerobic (without oxygen) processes.

Anaerobic respiration

• Lactic acid is a byproduct of anaerobic metabolism.

• It builds up to high levels within the muscles and eventually leads to fatigue during these high intensity activities.

Anaerobic respiration• In the absence of oxygen

• Glucose undergoes a process of fermentation.

• in the cytoplasm

• In human cells the waste product is lactic acid.

• 2 ATP are produced during anaerobic respiration per glucose

Chemical reaction for Anaerobic in muscle

C6H12O6 → 2C3H6O3 + E (150kJ mol−1)

[Glucose] [lactic acid] + Energy

• Lactic acid will build up causes fatigue

• Fast and deep breathing – supply extra oxygen to :– breakdown lactic acid into CO2 and H2O– Converted back to glycogen

• The amount of O2 needed = oxygen debt

Anaerobic in yeast

• In yeast, the waste product is ethanol and carbon dioxide

• Discuss:– The important of ethanol and carbon dioxide

production for human

Comparison

Between aerobic and anaerobic respiration:

–Place

–Reaction

–Product

–Energy produced

Characteristic of respiratory surfaces

• Large surface area for gas exchange

• Thin respiratory surface, one layer epithelial cells that allow oxygen and carbon dioxide to exchange.

• respiratory surfaces must be moist, gases can only cross cell membranes when they are dissolved in water or an aqueous solution

Insect respiratory structure

Tracheal system

• spiracles - openings on the sides of the thorax and abdomen

• usually one pair of spiracles per segment • The tracheae are invaginations of the cuticular

exoskeleton that branch throughout the body with diameters from only a few micrometers up to 0.8mm.

• The smallest tubes, tracheoles, penetrate cells and serve as sites of diffusion for oxygen and carbon dioxide

Fish respiratory structure

gills

Fish gills• The gills of bony fishes are covered by an

operculum.  They are four in number with intervening gill slits

• Branches of the afferent and efferent branchial arteries pass out to the tip of a gill filament on each side.  A rich capillary network, cross-connecting these branches and at right angles to them, occupies each lamella.

• the water flows directly opposite to the flow of blood in the lamellar capillaries. 

Amphibian

• Frogs have three respiratory surfaces :– skin:

• Frogs can breathe through their skin while they are in wet places.

• They can also exchange gases between the blood vessels in it, and with its outer environment.

• There are also mucus glands in the skin, these keep the skin moist.

• Their skin absorbs a lot of dissolved oxygen from the surrounding atmosphere.

– the thin membranes lining its mouth and pharynx.

– the lungs.

• Adult frogs have poorly developed lungs. Their lungs are used on dry land while the frogs are active.

• Gas exchanged by the lungs is used to make the vocal cords vibrate. They are located in the larynx, and are necessary for the sound generated by a frog.

• The frog inhales and exahales– When the frog breathes, the air enters the

mouth. The floor of the mouth drops, and the external nares open.

– The floor of the mouth rises and falls in a rhythmic pattern. These movements are interrupted by a rapid expansion and contraction of the sides of the body wall at less frequent intervals.

– At rest, frogs usually breathe through the lining of the mouth. This process only fills the lung occasionally.

Human respiratory structure

General structure of human respiratory system

• The lungs are large, lobed, paired organs

• in the thoracic cavity• Thin sheets of epithelium (pleura)

separate the inside of the chest cavity from the outer surface of the lungs.

• The bottom of the thoracic cavity is formed by the diaphragm.

Lung

• Bronchi are reinforced by cartilage ring to prevent their collapse

• They are lined with ciliated epithelium and mucus-producing cells.

• Bronchi branch into smaller and smaller tubes known as bronchioles.

• Bronchioles terminate in grape-like sac clusters known as alveoli.

• Alveoli are surrounded by a network of thin-walled capillaries.

• Only about 0.2 µm separate the alveoli from the capillaries due to the extremely thin walls of both structures.

alveolus

Ventilation • the mechanics of breathing in and out

• inhalation, – muscles in the chest wall contract, – lifting the ribs and pulling them, outward – diaphragm at this time moves downward

enlarging the chest cavity

• Reduced air pressure in the lungs causes air to enter the lungs.

• Exhalation – muscles in the chest wall relax, – lifting the ribs and pulling them, outward – diaphragm at this time moves downward

enlarging the chest cavity

• Increased air pressure in the lungs causes air to exit the lungs.

• Diffusion is the movement of materials from a higher to a lower concentration.

• The differences between oxygen and carbon dioxide concentrations are measured by partial pressures.

• The greater the difference in partial pressure the greater the rate of diffusion.

Gas exchange alveolus

Gas exchange

• Partial pressure of oxygen in alveolus is higher than in alveolar blood capillaries

• Oxygen from the air dissolve in water [moist] at alveoli lining and diffuse in blood

• Oxygen binds to hemoglobin in red blood cells to form oxyhaemoglobin.

• Oxyhaemoglobin is carried to all body cells by blood circulation

From cell to blood

Carbon dioxide - transported from the body cells back to the lungs as:

• 1 - bicarbonate (HCO3) - 60% – formed when CO2 (released by cells making

ATP) combines with H2O

• 2 - carbaminohemoglobin - 30% – formed when CO2 combines with hemoglobin

(hemoglobin molecules that have given up their oxygen)

• 3 - dissolved in the plasma - 10%

• Carbon dioxide diffuses in the opposite direction, from capillary blood to alveolar air.

• Partial pressure of carbon dioxide in the blood is higher than in the alveoli

• Carbon dioxide diffuse out to the alveoli

• Exhalation follows, to get rid of the carbon dioxide and completing the cycle of respiration.

From blood to alveolus

What are differences between inhaled and exhaled air?

Regulatory mechanism

• After vigorous exercise the rate of respiration increase and heartbeat increase– To supply more oxygen to the muscle – To eliminate more carbon dioxide from the

muscle

Resting stage

• Breathing rate = 16 – 18 breaths/minute

• Heartbeat rate = 60 – 80 beats/minute

After activities• Breathing rate = 30 – 40 breaths/minute

• Heartbeat rate = 120 – 150 beats/minute

• Vigorous exercise = concentration in the blood CO2 increase

• CO2 dissolve in water forming carbonic acid• pH blood drop• Detected by central chemoreceptor in medulla

oblongata• Nerve impulse send to respiratory centre • Resp. cen. send impulse to intercostal muscle

and diaphragm • Ventilation increase

Regulatory mechanism of O2 and CO2

CO2 Water

Carbonic acid pH

Central chemoreceptor [medulla oblongata]

Respiratory centre

Intercostals muscle diaphragm

Ventilation faster CO2 eliminate faster

Detected by

Impulse send

Impulse send

Respiration in plant

• Occurs all the time

• In daylight photosynthesis produces plenty of oxygen

• Used by plant in respiration processes

• At night O2 from atmosphere is used for respiration

Compare respiration and photosynthesis