Unit 2.3 The Respiratory System Flashcards
What is the function of the respiratory system?
It is to provide the body with he oxygen needed to carry out cellular respiration which maintains life.
The oxygen is taken from the air we breathe into our respiratory system and the CO2 is passed into the air we breathe out.
What does the respiratory system remove from the body.
It removes CO2 a poisonous waste product of respiration in cells.
The respiratory system have several different regions -what happens in the upper respiratory tract?
The upper respiratory tract is where air is taken into the body and warmed, moistened and filtered before it is passed into the lower respiratory.
What happens when the air is passed into the lower respiratory tract?
At this point in the lungs, the air comes into close contact with the capillary system of the pulmonary circulation and gas exchange occurs. oxygen moves from the air into the blood and co2 moves from the blood into the lungs.
What does the upper respiratory tract consist of?
The nose, pharynx, larynx and trachea.
What is the function of the upper respiratory tract?
The function of this part of the respiratory system is to transport the air from outside the body into the lower respiratory system.
What do the hairs at the entrance of the nostrils do?
They trap large particles of foreign material breathed in.
What does the rest of the nasal cavity do?
It has a large surface area lined with a mucous membrane which moistens and warm the air - the sticky mucus also traps particles including bacteria and viruses, smoke and dust.
What does the pharynx (throat) provide?
The pharynx provides a common passage to both the oesophagus and the trachea from the back of the nose.
What is the mechanism to prevent food going down into the lungs.
Epiglottis.
Where does the mucous membrane extend to?
The mucous membrane in the nasal cavity extends into the pharynx continuing the filtering process.
Where is lymph tissue present?
Lymph tissue is also present in the tonsils and lymph glands of the neck to provide defence against bacteria
What is the larynx?
The voice box/ Adams apple - it is the channel between the pharynx and trachea and helps you speak.
How do you speak?
As air flow from the lungs, the vocal cords close together and vibrate, creating sounds which you then shape into words using your palate, tongue, teeth and lips.
What is the trachea made up of?
The trachea is a tube made up of a smooth muscle and incomplete rings of cartilage for support, these are incomplete so food can be swallowed in the oesophagus as a complete ring of cartilage would obstruct the oesophagus.
What does the trachea pass down and divide into?
The trachea passes down the neck into the chest until it divides to form the right bronchus and left bronchus (Bronchi).
What is the trachea lined with? What is their function?
The trachea is lined with mucus secreting goblet cells and ciliated epithelium - the mucus traps the dust, dirt and pathogens from the air while the cilia beat and move the mucus including dust and pathogens away from the lungs.
What happens in the lower respiratory tract?
This is where the filtered, warm and moist air can begin its critical job of providing oxygen to and removing waste from the body.
At its lower end the trachea divides into 2 branches, the right and left bronchi which enter their respective lungs, structurally very similar to the trachea - the bronchi then divide into smaller tubes called bronchioles what is the structure of the bronchioles?
The bronchioles are much smaller tubes and do not have cartilage rings around them, they contain smooth muscle meaning they can dilate and constrict in response to environmental factors such as temperature of the air.
The bronchioles divide repeatedly to form a network of tiny tubules. What is at the end of the bronchioles?
The bronchioles end in the alveoli.
What is the structure of each alveolus?
Each alveolus is a tiny air sac with thin walls of flattened epithelial cells. They have a huge total surface area - flattened out would covered 20 table tennis tables. They are surrounded by a network of blood capillaries so that the distance for gasses to diffuse between the air in the alveoli and the blood is as short as possible.
How does the body maintain a steep concentration gradient between the alveoli and the blood in the capillaries in terms of oxygen in CO2?
By moving the air in and out of the lungs and keeping the blood circulating.
The alveoli and connecting bronchioles make up the structure of the lungs, spongy organs contained within what?
The rib cage to protect them from damage.
The lung are divided into a number of lobes, how many in each lung?
The right lung has three lobes and the left lung has two lobes.
What is each lung surrounded by what membrane?
Each lung is surrounded by the pleural membranes which have fluid between the 2 layers and high slide easily over each other to reduce friction in the thorax (chest cavity).
What are the muscles between the ribs?
The Intercostal muscles which are important for breathing.
What is across the base of the chest cavity?
The diaphragm - a muscular sheet which is domed in shape when it is relaxed.
What is the mixture of gases which make up the air we inhale?
78% nitrogen, 21% oxygen, 0.04% carbon dioxide
In the alveoli of the lungs, some of the oxygen is removed and more carbon dioxide is added in the process of gas exchange- as a result what is the percentage of gasses we exhale?
17% oxygen and 4% co2 - the air we exhale also contains a lot more water vapour which evaporate from the respiratory surfaces.
Breathing or ventilation of the lungs brought about by the movement of what?
Brought about by the movements of the ribcage and muscular diaphragm.
What are the 2 sets of intercostal muscles involved in moving the ribs called?
The internal intercostal muscles and the external intercostal muscles.
What 2 actions does normal breathing consist of?
Normal breathing consists of active breathing in, inspiration, followed by passive breathing out, expiration.
What state are the internal and external intercostal muscles and diaphragm in when you breathe in?
The internal intercostals are relaxed but the external intercostals contract, pulling the ribs upwards. the diaphragm muscles contract, flattening the diaphragm from its normal domed shape.
What happens to the thorax when you breathe in?
the volume in the thorax increases and pressure inside the thorax becomes lower than the pressure of air outside the body, as a result air moves into the lungs pushed in by atmospheric pressure down the pressure gradient - this is inspiration.
What happens when you breath deeply, either voluntarily or during exercise?
the external intercostal muscles contract more powerfully and the ribs are lifted further up and out - the increases the volume of the chest cavity even more, lowering the pressure so more air is forced into the lungs .
What type of process is inspiration?
Inspiration always involves muscle contractions so it is an active process using energy from respiration.
What type of process of normal expiration?
It is a passive process.
What state are the internal and external intercostal muscles and diaphragm in when you breathe out?
The internal intercostals are relaxed, the external intercostal muscles that have moved the ribs up and out are also relaxed. when the intercostal muscles relax, the ribs drop down and in again under gravity, it uses no energy. when the diaphragm relaxes, it curves back up into the thorax resuming its domed shape
What happened to the thorax when you breathe out?
The volume of the thorax becomes smaller again this increases the pressure inside the chest so the air is squeezed and forced out of the lungs
What type of process is expiration when you force the air out of the lungs?
In deep breathing expiration is active - the external intercostal muscles relax and the internal intercostal muscles contract pulling the ribs down and in hard and fast -this reduces the chest volume more than in passive exhalation increasing the pressure considerably and forcing more air out of the lungs. The contraction of the internal intercostals use energy from respiration so it is active exhalation.
Summary: what happens during inspiration?
External intercostal muscles contract to move the ribcage up and out, the diaphragm flatters and lowers and the volume of the chest cavity increases so the air pressure in the chest decreases - air flows into the lungs because there is a higher atmospheric pressure outside the lungs causing the air to be drawn into the lungs to equalise the difference.
Summary: what happens in passive expiration (shallow breathing):
The external intercostal muscles relax and the ribs drop down and in under gravity, the diaphragm relaxes and domes upwards, the volume of the chest cavity decreases so the internal pressure increases air moves out of the lungs, a passive process. - air moves out of the lungs because higher air pressure in lungs causes air ti be forced out of the lungs to equalise the difference.
Summary: what happens in active expiration (deep breathing):
The external intercostal muscle and the diaphragm relax and the diaphragm domes upward, the internal intercostal muscles contract and force the ribs down and in hard and fast, the volume of the chest cavity decreases so the internal pressure decreases air moves out the the lungs, an active process.
