I k s m e l l m i t m i r n a s a l l i n i n g t h a t I a m g o i n g t o f a i l t h i s t e s t , b u t m y p o p u l a t i o n u n d i c h a r e t o g e t h e r a n d

Biology summary I k s m e l l m i t m i r n a s a l l i n i n g t h a t I a m g o i n g t o f a i l t h i s t e s t , b u t m y p o p u l a t i o n u n d i c h a r e t o g e t h e r a n d w e r e s p o n s e s a d t o b i o l o g y a n d o u r b r o n c h i i s fi l l e d u p w i t h m a d i t y a n d c r y t i t y t h a t w e n e e d t o l e a r n 1.1 respiratory system 1.When you inhale air enters your body through your nasal cavity or the oral cavity 2.The air travels through the pharynx and larynx into the windpipe (trachea).

3.The windpipe splits into two tubes called bronchi through which the air enters the lungs.

4.Inside the lungs, the bronchi branch and air enters the many tiny tubes called bronchioles.Cold air can dry out the mucus lining of your respiratory system. This means that the air you inhale must we warmed up. This air is warmed up by blood running through tiny blood vessels in the lining of your nasal cavity.The lining of the windpipe and bronchi look moist.If you breathe in through your nose, the mucus in the nasal lining moistens the air you inhale.Pollen and germs make you ill The nose hairs filter the large particles out of the air you inhale. The smaller particles and germs get trapped by mucus in the nasal lining and in the linings of your windpipe and bronchi. This mucus is then swept to your pharynx by ciliated cells.The olfactory cells high up in your nasal cavity check the air for the presence of chemicals that form odours. You ran away from the odour.After being filtered, the air passes your pharynx which is a passageway for food and liquids. The lower part of your pharynx diverges into your trachea and your oesophagus.When you swallow food, the opening to your trachea must be closed.A thin plate of flexible cartilage called the epiglottis moves down and closes the trachea.If you speak and swallow at the same time, your epiglottis will not close the trachea complete When you ever had a drink come out through your nose because you were laughing and shallow at the same time, there is an opening between the nasal cavity and the pharynx.The uvula closes the nasal cavity when you swallow.After passing the pharynx, air enters your larynx.Inside the larynx are your vocal cords.Vocal cords two elastic folds of tissue that stretch across the trachea.When you exhale, you can produce sounds because the passing air causes the vocal cords to vibrate. Because of this is the larynx also called the voice box. 1 / 3

The trachea is situated in front of your oesophagus. The trachea must be kept open so that air can pass through unhindered. Therefore, the wall of the trachea contains C- shaped cartilage rings, which prevent the trachea from collapsing.The windpipe branches out into two short tubes called bronchi which then divide into many tiny bronchioles. Et the end of the bronchioles you will find tiny clusters of sacs called alveoli.

1.2 Gas exchange and respiration Air is a mixture of gases. It contains nitrogen, oxygen and carbon dioxide and water vapour.GasInhaled airExhaled air Nitrogen79 %79 % Oxygen21 %17 % Carbon Dioxide0,04 %4 % Water vapourvery littlea lot The composition of inhaled air and exhaled air is not the same.Fire uses wood as fuel and burns this with the help of oxygen to produce energy in the form of heat and light. Cells use glucose as fuel. Fire also produce a waste product like smoke which contains carbon dioxide. But your cells also produce waste.Whenever you burn fuel with oxygen, you produce e nergy, carbon dioxide and water vapour Called cellular respiration the process where cells break down glucose to get energy.We use the energy for life processes such as Keeping a constant body temperature Movement Replacing and adding (growing) cells Cellular respiration can be written down as follows Glucose + oxygen water vapour + carbon dioxide + energy When you burn wood in a campfire, this is called combustion Wood + oxygen water vapour + carbon dioxide + energy The carbon dioxide and water that your cells produced during respiration, is carried back to the lungs via your bloodstream. Oxygen from the inhaled air in your lungs travels also via the bloodstream towards the cells.The exchange of carbon dioxide and oxygen take place in the alveoli.The wall of an alveolus is one cell layer thick.Alveoli are surrounded by many tiny blood vessels called lung capillaries.These capillaries then connect to larger blood vessels called veins. Which bring the blood through the lungs. The wall of a capillary is also just one cell layer thick. This means that oxygen inside a alveolus can easily pass into your bloodstream and carbon dioxide easily pass out. The amount of carbon dioxide is high in the blood that comes from your cells and low in the alveoli. 2 / 3

In the process of diffusion, substances are transported from the alveoli to your blood and vice versa. Gases and liquids are made of particles who can diffuse. How does this work?This is an example 1.Your mother bought a bunch of flowers.

2.She puts them in a vase and puts the vase on the table.

3.At first you smell the scent of the flowers when you walk past, after a while you will smell them further away.

4.In the air surrounding the flowers there is a high concentration of scent particles.

5.On the other side of the room there is a lot of space left for scent particles.

6.The scent particles will move from the high concentration to the low concentration.Diffusion is the movement of particles from an area of higher concentration to areas of lower concentration, until the concentrations in both areas are equal. No energy needed.

1.3 Like a pair of bellows There are two ways in which you can breathe 1.Thoracic breathing (chest breathing) 2.Abdominal breathing (diaphragmatic breathing) Example: When you squeeze an empty plastic bottle, air is pushed out. This happens because air pressure outside the bottle is less than the pressure you create inside the bottle when you squeeze it. When you release your grip on the bottle, the air pressure inside the bottle becomes less than it is outside the bottle.When you inhale, the intercostals contract. Your ribs are pulled upwards and forwards.Your lungs and inside of the rib cage are each covered by a thin membrane.Between 2 membranes contains around 2 teaspoons of fluid. This fluid causes the lungs to stick to the inside of the ribcage and it also helps them to slide easily up and down.Diaphragmatic breathing involves contraction of your diaphragm which moves it downwards. Your diaphragm is a sheet of muscle that separates the thoracic cavity from the abdominal cavity.When you breathe out, your intercostals relax. Gravity pulls your ribcage back down and your diaphragm relaxes and moves back up. The lungs become smaller.The volume of air you inhale/exhale is called the tidal volume.Your tidal volume is about 500 ml.The maximum amount of air that you can expel from your lungs is called vital capacity.But there is still some air left in your lungs, called residual volume (about 1 liter) Calculate your lung volume = vital capacity + residual volume 1.4 Sick lungs Asthma is a chronic inflammation of the airways. It has a genetic factor.During an asthma attack, the tiny muscles around the smallest bronchioles contract. The cells that produce mucus also start producing more mucus than usual. This causes the bronchioles to become narrower so less air can travel towards the alveoli.What triggers an asthma attack Allergy Pollen, Dust, smoke

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