Exchange of materials with the environment - 3.3 Flashcards
3.3
Why do multicellular organisms exchange materials with their environment?
Multicellular organisms exchange materials with their environment to obtain essential nutrients such as oxygen and release unwanted materials such as carbon dioxide to maintain homeostasis.
What characteristics do exchange surfaces have to be efficient?
- Thin to reduce the distance that materials need to move during exchange.
- Moist to assist the transport of materials across the exchange surface.
- Large total surface area to provide more surface for the exchange of materials to take place.
- Rich blood supply to transport materials to and from exchange surfaces. (animals)
Define Diffusion.
Diffusion is the net movement of a substance from a region of higher concentration to a region of lower concentration until equilibrium (along the concentration gradient). Diffusion does not require any energy hence, it is passive transport. For example,Oxygen diffuses from the alveoli (high O₂) into the blood (low O₂), while carbon dioxide diffuses from the blood (high CO₂) into the alveoli (low CO₂).
Define Active Transport.
Active transport is the movement of substances from a region of low concentration to a region of high concentration (against the concentration gradient) using energy (ATP).
Passive Transport vs Active Transport.
Passive Transport - Requires no energy and moves susbtances along the concentration gradient (high to low).
Active Transport - Requires ATP and moves substances against the concentration gradient (low to high).
What is the respiratory system?
The respiratory system is a group of organs and tissues responsible for breathing and the exchange of gases (oxygen and carbon dioxide) between the internal and external environment. The respiratory system includes the nose, trachea, lungs, bronchi, bronchioles, and alveoli.
What are the function of the respiratory system?
The respiratory system’s primary functions include gas exchange (providing O₂ and removing CO₂), smelling (olfaction), speaking, filtering air, and warming & moistening air.
What is aerobic respiration?
Aerobic respiration is the process by which cells produce energy (ATP) and occurs in the mitochondria.
Equation -
C6H12O6 + 6O2 → 6CO2 + 6H2O (glucose + oxygen -> carbon dioxide + water + ATP)
What are the different organs of the respiratory system and what are their functions?
- Nose and Nasal Cavity – Filters, warm and moistened air breathed in and trap dust and pathogens with mucus and cilia nose hair.
- Pharynx – The throat sitting behind the nose and mouth, where air and food are passed through and air passes from the nasal cavity to the larynx.
- Larynx – The voice box is involved in sound production and protecting the trachea during swallowing. The larynx also contains epiglottis, preventing food from entering the trachea during breathing.
- Trachea – The windpipe, a tube that carries air from the larynx to the left bronchus and right bronchus and is lined with cilia to trap debris.
- Pleural Cavity – The space around the lungs that contains pleural
fluid to reduce friction during breathing. - Bronchi – Two large tubes that branch off the trachea and lead to each lung, branching into smaller bronchioles.
- Bronchioles – Smaller air passages that deliver air to the alveoli in the lungs from the bronchi.
- Lungs – The main organs for gas exchange mainly consist of alveoli, and the left lung is smaller than the right lung due to the heart being off centred to the right.
- Diaphragm – A dome muscle beneath the lungs that expands and contracts pulling air in and expelling air from the lungs respectively.
- Ribs – Bones that protect the lungs.
- Intercostal Muscles – Muscles between the ribs that contract and relax to elevate and lower the ribs, respectively.
What is ventilation?
Ventilation also known as breathing consists of inspiration (inhalation) and expiration (exhalation).
How does air move through the respiratory system?
Nose or Mouth – Air enters and is filtered, warmed, and moistened.
Nasal Cavity – Further filters and conditions the air.
Pharynx – Air passes through the throat.
Larynx – Air moves through the voice box.
Trachea – The windpipe that directs air to the bronchi.
Bronchi – Two branches that carry air into each lung.
Bronchioles – Smaller tubes that carry air deeper into the lungs.
Alveoli – Tiny air sacs where gas exchange occurs (oxygen in, carbon dioxide out).
What happens during inhalation?
Pressure - Decreases in the chest cavity.
Volume of Chest Cavity - Increases as the diaphragm contracts and moves downward.
Intercostal Muscles - Contract, raising the ribs and expanding the chest.
Ribs - Move upwards and outwards.
Diaphragm - Contracts and moves downward, increasing the chest cavity’s volume.
What happens during exhalation?
Pressure - Increases in the chest cavity.
Volume of Chest Cavity - Decreases as the diaphragm relaxes and moves upward.
Intercostal Muscles - Relax, causing the ribs to move downwards and inwards.
Ribs - Move downwards and inwards.
Diaphragm - Relaxes and moves upward, decreasing the chest cavity’s volume.
How does a balloon lung model represent inspiration and expiration using a bottle?
Inspiration -
Pulling the rubber sheet at the bottom of the bottle down increases the volume inside the bottle, decreasing pressure and causing the balloon (lungs) to inflate (air moves in).
Expiration -
Pushing the rubber sheet up decreases the volume inside the bottle, increasing pressure and causing the balloon (lungs) to deflate (air moves out).
How does gas exchange within the alveolus?
Alveoli are tiny air sacs with thin, moist walls that are one cell thick, allowing for rapid diffusion of gases and are surrounded by capillaries for efficient gas transfer.
Describe the process of gas exchange in humans.
Oxygen (O₂) diffuses from the alveoli into deoxygenated blood, while carbon dioxide (CO₂) diffuses from the blood into the alveoli to be exhaled.
Explain the composition of inhaled and exhaled air.
Inhaled air contains about 21% oxygen, 0.04% carbon dioxide and 78% nitrogen while exhaled air has approximately 16% oxygen, 4% carbon dioxide and 78% nitrogen due to gas exchange in the lungs.
What role do goblet cells and cilia play in the respiratory system?
Goblet cells produce mucus to trap particles and microorganisms, while cilia move the mucus up to the throat for swallowing or expulsion.
How does the respiratory system filter air?
The respiratory system filters air through mucus that traps particles, and cilia that push the mucus to the throat.
What is the significance of warming and moistening air in the respiratory system?
Warming and moistening air helps prevent respiratory tissue damage and aids in efficient gas exchange.
Describe the total lung capacity in adults.
The total lung capacity in adults is approximately 5 litres.
Explain vital capacity and its importance in respiratory health.
Vital capacity is the maximum amount of air that can be inhaled or exhaled during forced breathing. tal capacity is an important measure of lung function, as it indicates the strength and efficiency of the respiratory system
What is tidal volume and its approximate measurement?
Tidal volume is the normal volume of air breathed in or out in a single breath while at rest, approximately 0.5 liters.
Define Residual Volume.
Air remains in the lungs after full, forceful exhalation.
