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Biology Chapter 1
Respiration Stage: 8
1.1 The human respiratory system
โ Key Words โ Aerobic respiration โ Respiration โ Bronchiole โ Respiratory system โ Air sac โ Bronchus (plu; Bronchi) โ Trachea โ Larynx ~ Larynx is another word for the "voice box" โ Cartilage โ Vocal cords โ Voice box โ Windpipe Why do we need oxygen Respiration is one characteristic that is shared by all living organisms. "Respiration is a series of chemical reactions that happens inside every living cell." The type of respiration that most commonly happens in our cells is Aerobic respiration. Carbon dioxide is a waste product which is produced by our cells. Air enters the body through either; the mouth or the nose. The mouth and the nose are both connected to the trachea also known as the windpipe. There are cartilage rings around the trachea to prevent it from closing/collapsing. The trachea separates into two parts called the
bronchi (The bronchi also have cartilage rings). Each bronchi goes into each lung. It helps the oxygen go deep inside the lungs. The bronchi are divided into even smaller tubes called bronchioles. The structure of these tubes lets the oxygen travel even deeper into the lungs. The bronchioles end by several tiny bags called air sacs. From here, the oxygen makes it's journey into the blood, then the CO2 comes out because of exhalation.
1.2 Gas Exchange
โ Alveoli ~ Air sac โ Analogy โ Capillaries ~ Tiny blood vessels that are wrapped around the alveoli โ Diffusion ~ When the oxygen particles in the air are gases, so they move freely, through the thin - walled cells and into the blood. โ Expired Air โ Gas exchange โ Haemoglobin ~ The red pigment of the blood โ Inspired air โ limewater
Air sacs
The tiniest part of the lungs can be seen through the microscope. If you look at the lungs under the microscope, you will notice that the lungs are mostly holes. "These are called air sacs." Air sacs are also known as alveoli. There are many blood vessels that are wrapped around the alveoli, these blood vessels are capillaries. The alveolus has a thin layer of cells. It is visible that there is a capillary wrapped around the alveolus.
1.3 Breathing
Key words
โ Breathing โ Contract โ Relax
When you breathe in, the following things happen:
โ The intercostal muscles between the ribs contract. โ The muscles in the diaphragm contract. โ It increases the volume in the chest cavity. โ The pressure inside the lungs decreases. โ Oxygen moves through the trachea into the lungs.
When you breathe out, the following happen:
โ The intercostal muscles between the ribs, relax. โ The muscles in the diaphragm return to their normal sizes. โ It decreases the volume of the chest cavity. โ The pressure increases, hence the air is squeezed outside the lungs.
1.4 Respiration
Key words
โ Glucose โ Mitochondria
Releasing energy from glucose:
The energy in glucose is locked inside of it. Before the cells can use the energy from the glucose, they must release the energy from the glucose, and to do that, the mitochondria has to release the energy from the glucose. The mitochondria perform a chemical reaction, which is aerobic respiration.
Word equation for aerobic respiration:
Glucose + Oxygen -----> Carbon dioxide + Water
Chemical equation for aerobic respiration:
C6H12O6 + 6O2 -----> 6CO2 + 6H2O + energy/ATP
ATP: Adenosine Triphosphate
1.5 Blood
โ Key words โ Anti bodies โ Blood plasma โ Oxyhaemoglobin โ Pathogens โ Red blood cells โ White blood cells
Delivering the requirements for respiration in cells:
All cells need energy to survive. Each cell gets energy through a chemical reaction such as respiration. Hence, every cell needs a good enough supply of glucose and oxygen, the carbon dioxide and water are the by-products of the reaction that must be taken away. "The delivery and removal is done by the blood.
RBCs are the only cells in the human body that do not have a nucleus, neither do they have a mitochondria! They are full of haemoglobin. The structure of a red blood cell is related to its function. The haemoglobin helps the red blood cells to transport oxygen. โ "As the blood flows through the tiny capillaries next to the alveoli in the lungs, oxygen from the air diffuses into the red blood cells. โ Inside the red blood cell, the oxygen combines with haemoglobin. It forms a very bright red compound called oxyhaemoglobin. โ As the blood continues on its journey around the body, it passes cells that are respiring. The oxyhaemoglobin lets go of the oxygen and gives it to the cells. โ The blood, which has given away most of its oxygen, now travels back to the lungs to collect some more." Red blood cells do not have a nucleus or a mitochondria because they need more space for haemoglobin. Scientists think that RBCs do not have a mitochondria so that they do not use the oxygen and energy for themselves. Red blood cells are believed to be one of the tiniest cells in the entire body. Being minute helps them to get through tiny capillaries. Which means that they can get surprisingly close to the respiratory system.
White blood cells
Unlike the red blood cells, white blood cells have a nucleus. Some WBCs are are larger than RBCs. Some microorganisms can cause disease when they get inside the body, such microorganisms are called pathogens. White blood cells defend the body against the pathogens. Some types of white blood cells have the ability to push their cytoplasm out to make "finger" like structures to capture pathogens. Other types of white blood cells produce chemicals known as antibodies. They are little Y - shaped structures. Different kind of antibodies are needed for different kinds of pathogens. The antibodies will stick onto the pathogens. Sometimes, they kill the pathogens directly. Sometimes, they cluster the pathogens together so that they cannot move. This makes it easy for other white blood cells to capture and kill the pathogens
