This is What Actually Happens When We Breathe | Biology
Summary
TLDRThe video script delves into the intricate process of human respiration, highlighting the journey of air from the nostrils through the respiratory system to the alveoli, where gaseous exchange occurs. It explains the role of the lungs, the diaphragm, and the respiratory muscles in facilitating inhalation and exhalation. The script also details the composition of inhaled and exhaled air, emphasizing the diffusion of oxygen into the bloodstream and the expulsion of carbon dioxide. Furthermore, it touches on the respiratory center in the brain and how carbon dioxide levels regulate breathing rate, illustrating the critical balance required for life.
Takeaways
- 👃 The nostrils are the entry point for air, equipped with nasal hair to filter out dust, bacteria, and debris.
- 🔥 The nasal cavity warms the air with underlying blood vessels, preparing it for the respiratory system.
- 🌀 The pharynx further warms, moistens, and filters the air before it reaches the larynx, which remains open except during swallowing.
- 🗑️ The larynx and trachea act as additional filters, trapping and sweeping debris towards the mouth.
- 💨 The bronchi are the pathways that guide air into the lungs, which are the primary site for gaseous exchange.
- 🫁 The lungs are rich in blood supply and consist of lobes; the left has two, and the right has three, each enclosed in the pleural membrane.
- 💪 The diaphragm, a set of muscles below the lungs, changes volume to assist in breathing by expanding and contracting.
- 🌱 The bronchioles divide into smaller tubes that attach to alveoli, which are air sacs with thin walls and moist surfaces, ideal for gaseous exchange.
- 🔄 Alveoli facilitate the diffusion of oxygen into the blood and carbon dioxide out of the blood, with a structure that includes a large surface area and capillary lining for efficient gas exchange.
- 🌬️ Breathing involves both inhalation (inspiration) and exhalation (expiration), with the external intercostal muscles and diaphragm playing key roles in expanding and contracting the thoracic cavity.
- 🧠 The respiratory center in the brain's lower Medulla Oblongata is stimulated by carbon dioxide levels, regulating the breathing rate in response to increased or decreased levels.
Q & A
What are the main respiratory organs in humans?
-The main respiratory organs in humans are the lungs, which are located in the upper chest cavity.
How does the air enter the human body during inhalation?
-Air enters the human body through the nostrils, nasal passages, pharynx, larynx, trachea, bronchi, and bronchioles before reaching the alveoli.
What is the function of the nasal hair in the respiratory process?
-Nasal hair filters out dust, debris, and bacteria, preventing them from entering the body and thus avoiding infection.
What role does the pharynx play in the respiratory process?
-The pharynx warms, moistens, and filters the air before it continues its journey towards the lungs.
How does the trachea contribute to the respiratory process?
-The trachea traps debris and helps to sweep it out towards the mouth, ensuring that the air reaching the lungs is clean.
What is the significance of the diaphragm in breathing?
-The diaphragm, a set of muscles below the lungs, changes volume to assist in breathing by contracting and relaxing, thus aiding in the expansion and reduction of the thoracic cavity.
What are the structural features of the alveoli that facilitate gaseous exchange?
-Alveoli have thin walls, moist surfaces, and are covered by a network of blood capillaries, which allow for efficient gas diffusion. They also have a large surface area and are only one cell thick, enabling rapid and easy gas exchange.
What happens to the composition of air during the breathing process?
-During inhalation, the air contains approximately 21% oxygen, 0.04% carbon dioxide, 79% nitrogen, and variable amounts of moisture and dust. During exhalation, the air contains 17% oxygen, 4% carbon dioxide, 79% nitrogen, and is saturated with water vapor without dust, at a higher temperature of around 37°C.
How much of the inhaled oxygen actually diffuses into the bloodstream?
-Only about 4% of the inhaled oxygen diffuses into the bloodstream, with the rest being exhaled.
Why does the level of nitrogen remain the same during inhalation and exhalation?
-The level of nitrogen remains the same because it does not participate in the gaseous exchange process within the body.
What is the role of the respiratory center in the brain during breathing?
-The respiratory center, located in the lower Medulla Oblongata, is stimulated by the presence of carbon dioxide. An increase in carbon dioxide levels leads to an increase in the breathing rate.
What can happen if carbon dioxide levels drop excessively in the body?
-If carbon dioxide levels drop excessively, it can inactivate the respiratory center, potentially leading to death.
Outlines
🌬️ Breathing Mechanics and Gaseous Exchange
This paragraph delves into the intricate process of breathing, detailing the journey of air from the nostrils to the alveoli. It explains the role of the respiratory organs in filtering, warming, and moistening the air, as well as the gaseous exchange that occurs in the alveoli. The text highlights the structure and function of the alveoli, which are crucial for the efficient diffusion of oxygen into the bloodstream and the expulsion of carbon dioxide as a waste product. The paragraph also describes the physical changes in the thoracic cavity during inhalation and exhalation, driven by the contraction and relaxation of the intercostal muscles and the diaphragm. Furthermore, it touches on the composition of the air we breathe, the percentage of gases involved in the exchange, and the regulatory role of the respiratory center in the brain, which responds to carbon dioxide levels to adjust the breathing rate.
Mindmap
Keywords
💡Respiratory Organs
💡Inhalation
💡Exhalation
💡Alveoli
💡Diaphragm
💡Gaseous Exchange
💡Carbon Dioxide
💡Oxygen
💡Nitrogen
💡Medulla Oblongata
💡Adrenaline
Highlights
Lungs are the main respiratory organs in humans, located in the upper chest cavity.
Air enters the body through a complex pathway involving the nostril, nasal passages, pharynx, larynx, trachea, bronchi, and bronchiolus before reaching the alveoli.
Nasal hair filters dust, debris, and bacteria from the air, preventing infection.
The pharynx warms, moistens, and filters the air, while the glottis remains open except during swallowing.
The trachea and bronchus trap and sweep out debris towards the mouth.
The lungs, rich in blood supply, are the active site of gaseous exchange.
The left lung has two lobes, while the right lung has three, each enclosed within the pleural membrane.
The diaphragm, a set of muscles below the lungs, changes volume to assist breathing.
Bronchiolus tubes attach to alveoli, which are air sacs with thin walls and moist surfaces, covered by a network of blood capillaries.
Oxygen from the air diffuses into the blood supply near each alveolus in the lung, while carbon dioxide diffuses back as waste.
Alveoli have a large surface area and moist surfaces, facilitating efficient gas diffusion.
The walls of alveoli and blood capillaries are only one cell thick, allowing for fast diffusion.
During inhalation, external intercostal muscles contract, increasing the volume of the thoracic cavity and reducing air pressure, forcing air into the lungs.
During inspiration, the amount of oxygen is 21%, carbon dioxide 0.04%, and nitrogen 79%, with variable quantities of moisture and dust.
During exhalation, the amount of oxygen decreases to 17%, carbon dioxide increases to 4%, and the air is saturated with water vapor.
Only 4% of the oxygen entering the body is diffused into the bloodstream, with the rest being exhaled.
The amount of nitrogen remains the same during inhalation and exhalation, indicating it does not participate in the gaseous exchange process.
During expiration, internal intercostal muscles contract, reducing the volume of the thoracic cavity and increasing air pressure, forcing air out of the lungs.
The respiratory center in the lower Medulla Oblongata is stimulated by the presence of carbon dioxide, increasing the breathing rate when levels rise.
Adrenaline hormone increases metabolic rate and breathing during anxiety or anger.
Excessive drop in carbon dioxide levels can inactivate the respiratory center, potentially leading to death.
Transcripts
This is What Actually Happens When We Breathe
Gaseous Exchange in Man
Lungs are the main respiratory organs in humans.
They lie in the upper chest cavity.
Today,
we will take a trip with air
as it enters our body during inhalation
and comes back out during exhalation.
Air enters our body through the nostril,
nasal passages,
pharinx,
larynx,
trachea,
bronchi and bronchiolus,
before entering the alveoli.
The air enters through the nostril
where projecting nasal hair filters all dust and debris
and bacteria,
thus preventing infection.
Air that enters into the nasal cavity
where the blood vessels below the epithelium warm it.
Air then goes on to the pharynx
which warms, moistens and filters air
and then to glottis,
which is open up all time except when swallowing.
After passing through larynx and trachea,
which traps debris and sweeps it out towards the mouth,
it goes via bronchus
and finally enters the lungs.
The lungs are rich in blood supply
and are active site of gaseous exchange.
The left lung consists of two lobes,
while the right one consists of three.
Each lung is enclosed within the pleural membrane.
Below the lungs,
a set of muscles called diaphragm,
changes volume to assist breathing.
Inside the lungs,
the bronchus divides into smaller tubes called bronchiolus
the bronchiole attaches to alveoli at each of its edge.
Alveoli are air sacs with thin walls and moist surfaces
and network of blood capillaries covers alveoli.
Oxygen from the air diffuses into the blood supply
passing close to each alveolus in the lung.
Carbondioxide is diffused back to the alveoli as waste.
The alveoli have a fascinating structure
well adapted for gaseous exchange.
It is not only lined with capillaries to assist diffusion,
but also have a large surface area
to allow an increased rate of diffusion,
and moist surface that allows gases to dissolve
before diffusion occurs.
The walls of alveoli and blood capillaries
are only one cell thick,
so that the diffusion is fast.
There is also a short distance between alveoli and capillary
so that the diffusion occurs easily.
What Happens During Breathing?
The process of breathing
involves inhalation and exhalation,
also known as inspiration or expiration.
During inspiration,
external intercostal muscles contract,
ribs swing upwards and outwards,
diaphragm contracts and flatten down.
In turn, there is an increase in the volume of the thoracic cavity.
The increase of volume in the thorax cavity
reduces air pressure in the cavity and lungs.
Gases inside the lungs expand
to fill in available space.
This forces air into the lungs.
The amount of oxygen during inspiration is 21%,
carbon dioxide 0.04%,
nitrogen 79%,
moisture, dust in variable quantities
and the temperature of the air is around 20C.
The amount of oxygen during expiration is 17%,
carbon dioxide 4%,
nitrogen 79%,
saturated with water vapor,
without dust,
and the temperature of the air has now increased into 37C.
It is interesting to note here
that from the 21% entering the body,
only 4% of the oxygen is diffused into the blood stream.
The rest is exhaled out.
However,
the amount of nitrogen remains the same
during inhalation and exhalation,
showing that nitrogen does not involve
in the gaseous exchange process.
During expiration,
internal intercostal muscles contract,
ribs swing downwards and inwards,
hence the diaphragm relaxes and elevates.
There is a reduction in the volume of the thoracic cavity.
A reduction in the thoracic cavity volume
increases air pressure,
this forces air out of the lungs to the atmosphere.
Inside our brain,
the respiratory center is located
in the lower Medulla Oblongata.
The stimulus for the respiratory center
is the presence of the carbon dioxide.
When carbon dioxide level increases,
breathing rate increases as well.
When we are anxious or angry,
the adrenaline hormone increases metabolic rate and breathing.
If the levels of carbon dioxide drop excessively,
it inactivates the respiratory center
and this could lead to death.
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