Unit 10: Biological Molecules and Metabolic Pathways
Learning Aim B: Explore the effect of activity on respiration in humans and factors that can affect
respiratory pathways
Assignment title: Respiration in Humans
Respiration: Oxygen is supplied to the body during breathing, and carbon dioxide is expelled.
Occasionally, the term "respiration" is used to refer to processes other than only breathing. When
breathing, the only substances that enter and leave the body are carbon dioxide and oxygen. A
component of respiration is the exchange of oxygen and carbon dioxide between the blood and the cells
of the body. Lungs are the main component of the respiratory system. However, a few other organs are
also utilised throughout the breathing process. The tissues and organs of your respiratory system enable
your body to exchange oxygen for carbon dioxide. The nose, mouth, throat, larynx, lungs, and
diaphragm are among the components of the human respiratory system.
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Your nose and nasal cavity filter, warm, and moisturise the air you breathe. Airborne particles are
stopped from entering the lungs by nasal hairs and mucus made by nose cells. A long tube that extends
beyond the nasal cavity, the pharynx is where air exits the body. The pharynx serves as both a food and
air passageway. The "speech apparatus", also called the larynx, lies just below the pharynx. The larynx,
an organ, produces the voice. Sound is produced when air passes through the delicate lung tissue. A
long tube called the trachea extends into the lungs before dividing into the left and right bronchi. Also
known as trachea or trachea. Each lung bronchi divides into a series of smaller bronchioli. A small flap
known as the epiglottis covers the trachea when you eat or drink liquids. The epiglottis is controlled by
unconscious muscles, so food cannot enter the trachea and lungs. Alveoli reach through bronchioles.
Small sacs known as alveoli are found at the ends of the bronchioli. They resemble small bunches of
grapes. Carbon dioxide and oxygen are exchanged in the alveoli. This indicates that oxygen enters the
bloodstream as carbon dioxide escapes. Gases are transferred from the alveoli to the circulation by
simple diffusion. A band of muscle called the diaphragm spans the base of the ribcage. As the lungs fill
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, with air and the diaphragm contracts, the ribcage expands. When the diaphragm relaxes, it pushes air
out of the lungs and reduces the volume of the chest.
For our bodies' cells to live, we require oxygen. While our body cells work, carbon dioxide is released.
The body can take in oxygen from the outside air and expel carbon dioxide thanks to the respiratory
system, which includes the lungs. During inhalation, the diaphragm moves into the abdomen and pushes
the ribs upward and away from the body. By pumping air into the lungs through the mouth or nose, the
chest cavity enlarges. During exhalation, the diaphragm expands and the muscles of the chest wall
relax, allowing air to exit the respiratory system by the mouth or nose. Every few seconds during
inhalation, a sizable portion of the millions of alveoli fill with air. The alveolar walls' tiny capillaries
enable oxygen to flow from the alveoli into the circulation. As oxygen enters the bloodstream, it is
absorbed by haemoglobin found in red blood cells. After returning to the heart, the oxygen-rich blood is
subsequently circulated through the arteries to the body's oxygen-starved tissues. Little capillaries in the
body's tissues release haemoglobin, allowing oxygen to reach the cells. Cells discharge carbon dioxide
into the capillaries, where the bulk of it dissolves in the blood plasma. The carbon dioxide-rich blood is
subsequently returned to the heart through the veins. The heart pumps this blood to the lungs, where it
enters the alveoli and is exhaled.
Aerobic Respiration: By using oxygen, the process of aerobic respiration breaks down food molecules.
The word "aerobic respiration" refers to air containing oxygen. Glucose is a key respiratory substrate
and a molecule that is frequently used in respiration. Thereafter, ATP molecules are used to store the
energy produced by the oxidation of glucose. The aerobic respiration word equation is:
glucose + oxygen → carbon dioxide + water (+ ATP made)
C6H12O6 + 6O → 6CO2 + 6H2O
Anaerobic Respiration: The bulk of species cannot continue to breathe if the oxygen supply is shut off;
nevertheless, some organisms and tissues can. When oxygen concentrations are minimal to non-
existent, anaerobic respiration takes place. When only a small percentage of the glucose molecule
breaks down during anaerobic respiration, only a portion of its energy can be released. Hence, only
about a tenth of the energy that aerobic respiration releases is released during the process. This implies
that ATP synthesis may be reduced. Food's glucose is transformed into alcohol and carbon dioxide
without the presence of oxygen while also producing energy. Cramping is a result of anaerobic
respiration occurring within muscle cells. Lactic acid is created when glucose partially breaks down in
the absence of oxygen, which causes muscle cramping. Strenuous activity relieves cramps because a hot
shower improves blood circulation throughout the body, which in turn increases the amount of oxygen
available to the cells.
Glucose → Alcohol + Carbon dioxide + Energy
glucose → lactic acid (+ ATP made)
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