L.O.2-Muscle Fibres.
Introduction.
Skeletal muscle is made up of bundles of individual muscle fibers called myocytes. Each myocyte contains many myofibrils, which are strands of proteins (actin and myosin) that can grab on to each other and pull. This shortens the muscle and causes muscle contraction. (www.sportsmedicine.about.)
Who also quote ‘’our muscle fiber type may influence what sports we are naturally good at or whether we are fast or strong.’’
Muscle fibres types can be broken down into two main types:
- Slow twitch (Type I) muscle fibres
- Fast twitch (Type II) muscle fibres
These Fast twitch fibres can be further categorized into
• Type IIa Fibres.
• Type IIb Fibres.
Slow Twitch (Type I)
The slow muscles are more efficient at using oxygen to generate more fuel (ATP) for continuous, extended muscle contractions over a long time. They fire more slowly than fast twitch fibres and can go for a long time before they fatigue.
Fast Twitch (Type II).
Because fast twitch fibres use anaerobic metabolism to create fuel, they are much better at generating short bursts of strength or speed than slow muscles. However, they fatigue more quickly. Fast twitch fibres generally produce the same amount of force per contraction as slow muscles, but they get their name because they are able to fire more rapidly.
1. Type IIa Fibres - These fast twitch muscle fibres are also known as intermediate fast twitch fibres. They can use both aerobic and anaerobic metabolism almost equally to create energy.
1. Type IIb Fibres -These fast twitch fibres use anaerobic metabolism to create energy and are the "classic" fast twitch muscle fibres that excel at producing quick, powerful bursts of speed. This muscle fibre has the highest rate of contraction of all the muscle fibre types, but it also has a much faster rate of fatigue.
Human muscles contain a genetically determined mixture of both slow and fast fiber types. On average, we have about 50 percent slow twitch and 50 percent fast twitch fibers in most of the muscles used for movement.
Sporting examples.
With this sport a mixture of all 3 muscles fibres is necessary,
Using the different muscles fibres during different times within the game to benefit a performance.
Slow twitch fibres will help when a longer period of play is occurring, for example if the goal keeper goes for an interception at the edge of the third then has to follow back to the shooting D to defend a shot she uses energy over a longer period of time rather than one short sharp burst of power. The slow twitch fibres help facilitate this need and take over work from the other muscle fibres to become the main working type.
At a centre pass the receivers (WA +GA) will need to be ready to produce a short sharp action of movement in order to part from their opposition and gain possession, in Order to do this Fast Twitch fibres(II) are activated and take control over the body’s muscles fibres. When a player side steps or turns to get away from a defender they display a burst of movement in both the legs and core and so need these fibres to help the sequence.
Type IIa Fibres – Can be used throughout the game, combining both the anaerobic and aerobic systems together equally.
Anaerobic energy systems - help to supply energy for no more than 6-8 seconds. (Jumping in for an interception when defending a pass in netball)To get its power it uses ‘high energy’ stored body chemicals – such as adenosine troposphere (ATP) and creatine phosphate (CP) and a chemical reaction that ‘fires’ them up, As well as supplying a source Explosive energy.
Aerobic energy systems - Aerobic workouts are often also called ‘steady state’ and provide players with a base of fitness. For netball this would mean the ability to continue performing to a steady level for the duration of the game.
Type IIb Fibres -These excel at producing quick, powerful bursts of speed. And so are useful for various times throughout the game, jumping, intercepting, passing, shooting defending etc…And so are very useful for the sport.
Olivia McCarthy 12PDL.
L.O.3 – Identify the major structure of the Cardio vascular system.
Introduction.
Our cardiovascular system is made up of the heart, blood vessels (arteries, veins and capillaries) and blood which together provide the tissues and cells with the essentials for life, oxygen and nutrients.
Here is a quick outline of how our cardiovascular system operates, taken from (www.bupa.co.uk/) ‘’Oxygen makes up about a fifth of the atmosphere. You breathe air through your mouth and nose and it travels to your lungs. Oxygen from the air is absorbed into your bloodstream through your lungs. Your heart then pumps oxygen-rich ('oxygenated') blood through a network of blood vessels – the arteries – to tissues including your organs, muscles and nerves, all around your body. When blood reaches the capillaries in your tissues it releases oxygen, which cells use to make energy. These cells release waste products, such as carbon dioxide and water, which your blood absorbs and carries away. The used (or 'deoxygenated') blood then travels along your veins and back towards your heart. Your heart pumps the deoxygenated blood back to your lungs, where it absorbs fresh oxygen, and the cycle starts again.’’ From this quote we gather how extremely important our cardiovascular system is, understanding how each part of the process is broken down into small chunks which are allocated as the jobs and functions of different organs and parts of our system. In this L.O. each will be studied and explained to understand each aspect of the cardiovascular system.
The structure and function of the heart.
The heart is a muscular pump that beats continuously and forms part of the cardiovascular system, cardio meaning heart and vascular meaning the circulatory network of the muscles.
The heart lies behind the sternum and rib cage, which offer protection. In adults it is about the size of a clenched fist although trained elite athletes often experience cardiac hypertrophy, which is an enlargement of the heart.
(http://en.wikipedia.org)
In terms of structure, the heart is composed of four chambers;
· The two top chambers (the superior part of the heart) are called Atria
· The two lower (Inferior chambers) are termed ventricles.
The ventricles are much more muscular than the atria since it is here that the pumping action of the heart takes place. As well as this the heart can be divided into left and right halves. This separation is essential for the heart to carry out its function effectively since each side takes on a different role;
· The left side of the heart is responsible for circulating blood throughout the body
· The right side is responsible for ensuring oxygen-poor blood is pumped to the lungs here it can be re-oxygenated.
The hearts major vessels act as entry and exit points for the blood to enter or leave the heart, and are situated towards the top half of the heart. To ensure a smooth passage of blood flow through the heart, a number of valves exist. These valves make sure that the blood only flows in one direction and are responsible for the beating sound of the heart, the first half of the beat sound results from the closure of the atrio-ventricle valves and the second much sharper beat occurs when the semi-lunar valves snap shut.
The muscular wall of the heart is called the myocardium and is found between the endocardium on the inside (which lines the chambers) and the pericardium on the outside (a visceral membrane forming the pericardial sac in which the heart sits). Covering the exterior of the heart are coronary arteries which feed the heart muscle with blood, being a muscle it requires fuel to keep the pumping action working continually.
The Cardiac cycle.
The cardiac cycle refers to the process of cardiac contraction and blood transportation through the heart.’’(www.wiki.com) as mentioned before, the heart can be viewed as two separate pumps to serve its dual purpose, the cardiac cycle explains the sequence of events that take place during one complete heart beat, this includes the filling of the heart with blood and then emptying into the arterial system.
There are 4 stages to each heart beat;
1. Atrial diastole
2. ventricular diastole
3. Atrial systole
4. Ventricular systole.
Cardiac Output.
Cardiac output = Stroke volume x Heart rate.
Q S.V H.R
Stroke volume-the amount of blood ejected in one beat. And has an average rate from the number of heart beats per minute.
The Blood.
The bloods functions are fundamental to life and include;
· Transportation of nutrients
· Protection
· Maintenance of homeostasis.
The blood is vital in marinating the body’s state of equality through hormone and enzyme activity as well as being involved in body temperature control.
Two types of blood vessels carry blood throughout our bodies;
1. Arteries
2. Blood vessels.
Arteries carry oxygenated blood from the heart to the rest of the body. Blood then travels through veins back to the heart and lungs, where it receives more oxygen. The blood that flows through this network of veins and arteries is whole blood, which contains three types of blood cells:
1. red blood cells (RBCs)
2. white blood cells (WBCs)
3. platelets
Blood vessels ‘’are the vascular network through which blood flows to all parts of the body and comprises of arteries, arterioles, capillaries, veins and venules.’’
Arteries and Arterioles.
Arteries are high pressure vessels which carry blood from the heart to the tissues. The largest artery in the human body is the aorta which is the main artery leaving the heart. This constantly subdivides and gets smaller until they become arterioles.
They are composed of three layers of tissue ;
-Outer fibrous layer
-Thick middle layer
-Thing lining of cells to the inside
The muscular wall of the artery helps the heart pump the blood. When the heart beats, the artery expands as it fills with blood. When the heart relaxes, the artery contracts, exerting a force that is strong enough to push the blood along.
Veins and Venules.
Veins are low pressure vessels which return blood to the heart. The structure is similar to arteries, Venules are the smallest vein and transport bloody away from the capillary bed into the veins, Vein gradually increase in thickness the nearer to the heart they get until they reach the largest vein in the human body, the venae cavae which enters the right atrium of the heart.
(www.s-cool.co.uk)
Capillaries.
Capillaries are the functional units of the vascular system and are just thin enough to allow red blood cells to squeeze through their wall. As they are so small, large quantities are able to cover the muscle, which ensures efficient gases exchange.
Bibliography.
Previous Classroom notes.
P.e and sport examined.
Olivia McCarthy 12PDL.
L.O.4 – Identify the major Structure and Function of the Cardio Vascular system (part 2)
Introduction.
Our cardiovascular system is made up of the heart, blood vessels (arteries, veins and capillaries) and blood which together provide the tissues and cells with the essentials for life, oxygen and nutrients.
Here is a quick outline of how our cardiovascular system operates, taken from (www.bupa.co.uk/) ‘’Oxygen makes up about a fifth of the atmosphere. You breathe air through your mouth and nose and it travels to your lungs. Oxygen from the air is absorbed into your bloodstream through your lungs. Your heart then pumps oxygen-rich ('oxygenated') blood through a network of blood vessels – the arteries – to tissues including your organs, muscles and nerves, all around your body. When blood reaches the capillaries in your tissues it releases oxygen, which cells use to make energy. These cells release waste products, such as carbon dioxide and water, which your blood absorbs and carries away. The used (or 'deoxygenated') blood then travels along your veins and back towards your heart. Your heart pumps the deoxygenated blood back to your lungs, where it absorbs fresh oxygen, and the cycle starts again.’’ From this quote we gather how extremely important our cardiovascular system is, understanding how each part of the process is broken down into small chunks which are allocated as the jobs and functions of different organs and parts of our system. In this L.O. each will be studied and explained with depth in order to help us understand each aspect of the cardiovascular system.
The Heart.
(www.google.co.uk)
The heart is the organ that supplies blood and oxygen to all parts of the body. Our heart is an organ located in the thoracic cavity. It lies just underneath the sternum and between the lungs just posterior to the breastbone, between the lungs and superior to the diaphragm. In adults it is about the size of a clenched fist although trained elite athletes often experience cardiac hypertrophy, which is an enlargement of the heart. Weighing on average about 10.5 ounces.
The heart consists of three tissue layers:
-Endocardium
-Myocardium
-Pericardium
The Endocardium is the innermost layer, a inner serous membrane consisting of flattened epithelium which lines the hearts chambers and is bathed in blood. Its function being to prevent friction between the heart muscle and flowing blood.
The Myocardium is the thick middle layer of the heart, forming the largest part of the heart wall. Its cells are unique in that they physically resemble skeletal muscle but have electrical properties. These cells also contain specialized structures that help to rapidly conduct electrical impulses from one muscle cell to another, enabling the heart to contract.
The Pericardium is a protective sac surrounding the heart, its outer, double layered bag contains a thin film of fluid which consists of plasma minus fibrinogen ( a blood protein used in the clotting mechanism) Its job helps to reduce friction-likewise to the Endocardium and maintain the hearts shape.
· Chambers of the Heart
The dynamic action of the heart is that of a dual-action pump in that both sides contract simultaneously, even though the functions of the two sides are entirely different- The heart is divided by a partition into two halves. The halves are in turn divided into chambers.
· The two top chambers (the superior part of the heart) are called Atria
· The two lower (Inferior chambers) are termed ventricles.
The ventricles are much more muscular than the atria since it is here that the pumping action of the heart takes place. As well as this the heart can be divided into left and right halves. This separation is essential for the heart to carry out its function effectively since each side takes on a different role;
· The left side of the heart is responsible for circulating blood throughout the body
· The right side is responsible for ensuring oxygen-poor blood is pumped to the lungs here it can be re-oxygenated.
The hearts major vessels act as entry and exit points for the blood to enter or leave the heart, and are situated towards the top half of the heart. To ensure a smooth passage of blood flow through the heart, a number of valves exist. These valves make sure that the blood only flows in one direction and are responsible for the beating sound of the heart, the first half of the beat sound results from the closure of the atrio-ventricle valves and the second much sharper beat occurs when the semi-lunar valves snap shut.
The muscular wall of the heart is called the myocardium and is found between the endocardium on the inside (which lines the chambers) and the pericardium on the outside (a visceral membrane forming the pericardial sac in which the heart sits). Covering the exterior of the heart are coronary arteries which feed the heart muscle with blood, being a muscle it requires fuel to keep the pumping action working continually.
· The Cardiac cycle.
There are 4 stages to each heart beat;
1. Atrial diastole
2. ventricular diastole
3. Atrial systole
4. Ventricular systole
Cardiac Cycle : Diastole Phase
During the diastole phase the heart relaxes for 0.5 seconds during which time a sequence of events occur, the atria and ventricles are relaxed. Blood flows into the right and left atria. The valves located between the atria and ventricles are open, allowing blood to flow through to the ventricles.
Cardiac Cycle: Systole Phase
During the systole phase, the ventricles contract pumping blood into the arteries. The right ventricle sends blood to the lungs via the pulmonary artery (which carries deoxygenated blood from the heart to the lungs.) The left ventricle pumps blood to the aorta (this distributes oxygenated blood to all parts of the body and is known for being the largest artery in the human body.) Here is a summary of the events that occur during the systole phase:
· The ventricles contract.
· Atrioventricular valves close and semilunar valves open.
· Blood flows to either the pulmonary artery or aorta.
One cardiac cycle is completed when the heart fills with blood and the blood is then pumped from the heart. The audible sounds that can be heard from the heart are made by the closing of the heart valves. These sounds are referred to as the "lub-dupp" sounds. The "lub" sound is made by the contraction of the ventricles and the closing of the atrioventricular valves. The "dupp" sound is made by the semilunar valves closing.
· Cardiac Output.
‘’Cardiac output is the amount of blood that is pumped out of the heart from one ventricle per minute.’’(www.sport/co/expl.com) Cardiac output = Stroke volume x Heart rate.
Q S.V H.R
Cardiac output is a function of heart rate and stroke volume. The heart rate is simply the number of heart beats per minute. The Stroke volume is equal to the amount of blood ejected in one beat. And has an average rate from the number of heart beats per minute. Increasing either heart rate or stroke volume increases cardiac output. The below quote states why our cardiac output is a key influence within our bodys, taken from (www.skillstat.com)
‘’Cardiac output is vital to our well-being. Simply, cardiac output is intimately connected to energy production. Ample perfusion to the tissues yields an abundant energy supply. Poor tissue perfusion results in critical shortages of energy and often diminished function.’’
The Blood.
‘’Blood delivers nutrients, removes wastes and also transports messengers such as hormones around our body therefore facilitating communication and responsiveness between various organs. This before information quoted from (http://www.skillstat.com/) explains and informs us of the bloods main basic functions and responsibilities. Below is a deeper look into the blood, in order to widen our knowledge.
Blood consists of cells and cell fragments surrounded by plasma. The bloods functions are fundamental to life and include;
· Transportation of nutrients
· Protection
· Maintenance of homeostasis.
The blood is responsible for transporting oxygen to the body’s cells and removing unwanted substances such as Carbon dioxide from the muscles and to the lungs. It protects the body by containing cells and chemicals which are central to the immune system, these help to fight off infection and illness.
The blood is vital in marinating the body’s state of equality through hormone and enzyme activity as well as being involved in body temperature control.
Blood is a mixture of two components: cells and plasma.
The cellular portion of blood contains red blood cells, white blood cells and platelets.
Plasma is the liquid portion of the blood, which distributes the substances it contains as it circulates throughout the body.
Two types of blood vessels carry blood throughout our bodies;
1. Arteries
2. Blood vessels.
Arteries carry oxygenated blood from the heart to the rest of the body. Blood then travels through Veins back to the heart and lungs, where it receives more oxygen.
The blood that flows through this network of veins and arteries is whole blood, which contains three types of blood cells:
1. red blood cells (RBCs)
2. white blood cells (WBCs)
3. platelets
(http://kidshealth.org)
Blood vessels ‘’are the vascular network through which blood flows to all parts of the body and comprises of arteries, arterioles, capillaries, veins and venules.’’
Arteries and Arterioles.
Arteries are high pressure vessels which carry blood from the heart to the tissues. The largest artery in the human body is the aorta which is the main artery leaving the heart. This constantly subdivides and gets smaller until they become arterioles.
They are composed of three layers of tissue;
-Outer fibrous layer
-Thick middle layer
-Thing lining of cells to the inside
The muscular wall of the artery helps the heart pump the blood. When the heart beats, the artery expands as it fills with blood. When the heart relaxes, the artery contracts, exerting a force that is strong enough to push the blood along.
Veins and Venules.
Veins are low pressure vessels which return blood to the heart. The structure is similar to that of arteries, Venules are the smallest vein and transport blood away from the capillary bed into the veins, Veins gradually increase in thickness the nearer to the heart they get, until they reach the largest vein in the human body, the venae cavae which enters the right atrium of the heart.
(www.s-cool.co.uk)
Capillaries.
A capillary is an extremely small blood vessel located within the tissues of the body, which transports blood from the arteries to the veins. Capillaries are the functional units of the vascular system and are just thin enough to allow red blood cells to squeeze through their wall. As they are so small, large quantities are able to cover the muscle, which ensures efficient gases exchange.
Bibliography.
· (www.bupa.co.uk/)
· Previous Classroom notes.
· P.e and sport examined.
· (www.s-cool.co.uk)
· Physical Education & the study of sport- R.J.Davis et al. 1991
Olivia McCarthy 12PDL.
The Structure of The Respiratory System-Mr. Evans.
Introduction.
The respiratory system if often studied in combination with the cardiovascular system, since the two systems work together to ensure an efficient and continuous supply of oxygen to the body’s cells. Respiration can be divided into two processes;
· External respiration
· Internal respiration
External respiration involves the movement of gases into and out of the lungs, supplying oxygen to our blood stream and the exchange of gasses between the lungs and the blood know as pulmonary diffusion.
Internal respiration includes getting oxygen to the body’s cells, exchanging oxygen and carbon dioxide in the cells and removing carbon dioxide and waste from the body
Below is an introduction to the respiratory system, outlining the structure of each component.
On its journey to the lungs, air is drawn into the body and passes through many different structures;
Nasal passages.
(www.google.co.uk/imgres)
Air is drawn into the body via the nose. The nasal cavity is divided by a cartilaginous septum, forming the nasal passages. The interior structures of the nose help the respiratory process by performing the following important functions.
1. The mucus membranes and blood capillaries moisten and warm the inspired air
2. The ciliated epithelium filters and traps dust particles which are moved to the throat for elimination
3. The small bones known as chonchae increase the surface area of the cavity to make the process more efficient.
The Lungs.
The lungs are two thin-walled elastic Spongy, saclike respiratory organs in the chest cavity which, together with the heart, work to remove carbon dioxide from the blood and provide it with oxygen.
Below is a paragraph taken form www.daviddarling.com explaining the structure of the lungs.
‘’The left lung is longer, narrower, and has a smaller volume than the right lung it shares space in the left side of the chest with the heart. The right lung is divided into three lobes and each lobe is supplied by one of the secondary bronchi. It has an indentation, called the cardiac notch, on its medial surface for the apex of the heart. The left lung has two lobes.’’
As we breathe in and out, the lungs inflate and deflate with air, taking oxygen into the body and expelling carbon dioxide from the body. The lungs are soft and spongy because they are mostly air spaces surrounded by the alveolar cells and elastic connective tissue.
Larynx
Known commonly as the voice box is found within the neck of humans and is involved in the production of sound and also serves to protect the upper part of the trachea. The larynx houses the vocal folds and is shaped like a funnel, with walls of cartilage and a system of muscles. Air entering the larynx passes over the vocal chords and into the trachea. In swallowing, the larynx is drawn upwards and forwards against the base of the epiglottis, thus preventing entry of food.
The larynx is often divided into three sections: sublarynx, larynx, and supralarynx. It is formed by nine cartilages;
– the epiglottis
– thyroid
– cricoid
– arytenoid(2)
– corniculate (2)
– cuneiform(2)
All are connected to each other by muscles and ligaments and lined with mucous membrane.
(www.daviddarling.info)
The trachea.
Trachea is the major airway leading from the throat to the lungs. The trachea or windpipe is approximately 10cm in length and lies in front of the oesophagus. It is composed of 18 horseshoe shaped rings of cartilage which are also lined by mucus membrane and ciliated cells which provide the same protection against dust as the nasal passageways. The front of the trachea arches producing an oval rather than round tubular structure with a diameter (from side to side) of about an inch. The trachea terminates in two branches, and directs air into the right and left primary bronchi.
The Epiglottis.
The epiglottis is flap of cartilage located in the throat behind the tongue and in front of the larynx. The epiglottis is usually upright at rest allowing air to pass into the larynx and lungs. When a person swallows the epiglottis folds backward to cover the entrance of the larynx so food and liquid do not enter the windpipe and lungs. After swallowing the epiglottis returns to its original upright position.
The Bronchi and Bronchioles.
Bronchus is a secondary branch of the airways that connect the lungs and the primary airway. The main bronchi branch directly from the trachea at about mid-lung, with the right main bronchus channelling air to the right lung and the left main bronchus directing air to the left lung. Each main bronchus nearly immediately branches into lobular bronchi, three in the right lobe and two in the left lobe. Bronchi become increasingly smaller as they branch deeper into the lungs. Rings of cartilage give larger bronchi rigidity and support. Smaller bronchi have fewer and thinner cartilage rings, and bronchioles, the tiniest of the bronchi, have thin walls of only smooth muscle tissue with no cartilage it is here that pulmonary diffusion occurs.
The Alveoli.
The alveoli are responsible for the exchange of gasses between the lungs and the blood. The alveolar walls are extremely thin and are composed of epithelial cells which are lined by a thin film of water, essential for dissolving oxygen from the inspired air.
Surrounding each alveolus is an extensive capillary network which ensures a smooth passage of oxygen into the pulmonary capillaries. It has been estimated that each lung contains up to 150million alveoli, providing a tremendous surface area for gas exchange. The alveoli walls also contain elastic fibres which further increase the surface during inspiration.
The Diaphragm.
The diaphragm muscle is a sheet of muscle essential for humans to breathe. It is a dome-shaped cavity near the lungs, between the thoracic cavity of the upper chest and the abdominal cavity of the stomach. The diaphragm muscle extends across the bottom of the ribcage and is the principle muscle of respiration. It is a muscle that contracts and relaxes as breathing takes place.
Below is a more indepth understanding of the diaphragm as taken from (www.wisegeek.com)
‘’Composed of two main parts called the peripheral muscular part and the central aponeurotic part, the diaphragm muscle is a complex muscle consisting of fibers and tendons. The fibers of the peripheral muscular part converge to the central part. These fibers include the sternal, costal, and lumbar parts. The costal part descends from the ribs to compose the left and right parts of the dome that contract and expanding during respiration. The lumbar part attaches to the vertebrae in the back and connects to each side of the aorta.’’
Intercostal Muscles.
Picture showing the location of the intercostal muscles taken from (www.shapeandbuildmuscle.com)
The intercostal muscles are found between the ribs and. and there are two kinds;
Internal intercostals
External intercostals
The internal intercostal muscles (found in the inside of the ribcage) extend from the front of the ribs, and go around back, past the bend in the ribs. These muscles work alternatively to lift and compress the ribcage in order to permit respiration.
The external intercostal muscles (situated outside of the ribcage) wrap around from the back of the rib. They consist of eleven muscles that envelop each side of the exterior of the rib cage.
Bibliography.
– (www.wisegeek.com)
– (www.beltina.org)
– (www.buzzle.com)
– The world of sport examined (second edition-2001) - Paul Beashel, Andy Sibon, John Taylor.
- Classroom notes.
Olivia McCarthy 12PDL.
The lungs are soft and spongy because they are mostly air spaces surrounded by the alveolar cells and elastic connective tissue.
From the above statement collected from the before source we can conclude that our lungs hold a complex and important structure. Like wise its function, roles and responsibilities are essential and the following quotation taken from (www.chiff.com/health/lungs.) helps us to understand this.
‘’The main job of the lungs is to take oxygen from the atmosphere and put it in the bloodstream, while simultaneously taking carbon dioxide out of the blood stream and ejecting it in to the atmosphere.’’
The lungs perform this vital role by contracting and expanding, a job performed by the diaphragm muscle.
As we breathe in and out, the lungs inflate and deflate with air, taking oxygen into the body and expelling carbon dioxide from the body.
The diaphragm, in turn, receives signals from the brain telling it when to speed up (while you are running or exercising) or when to slow down (while you are at rest or sleeping).
When the diaphragm contracts, the lungs are pulled downwards, and their capacity is increased, which pulls air in. The diaphragm then relaxes, and whatever oxygen was not absorbed by the body, along with the carbon dioxide being ejected by the body, is allowed to leave the lungs.
In addition to providing the body with oxygen-rich blood, lungs are partially responsible for acting as a protective cushion for the heart which they almost completely surround.
The lungs are also important in the body's defence against infection and other harmful environmental factors. Inhaled particles or infectious agents pass through the mouth or nose and lodge in the lungs.
Mucus, a sticky fluid produced in the lungs, can trap these inhaled agents and aid the lungs' protective white blood cells in the engulfment and destruction of bacteria and other harmful materials. The cilia beat with a rhythm fast enough, and a force sufficient enough, to propel mucus and cells up the airways to be coughed out or swallowed.
The larynx is often divided into three sections: sublarynx, larynx, and supralarynx. It is formed by nine cartilages;
Trachea is the major airway leading from the throat to the lungs. The trachea or windpipe is approximately 10cm in length and lies in front of the oesophagus. It is composed of 18 horseshoe shaped rings of cartilage which are also lined by mucus membrane and ciliated cells which provide the same protection against dust as the nasal passageways. The front of the trachea arches producing an oval rather than round tubular structure with a diameter (from side to side) of about an inch. The trachea terminates in two branches, and directs air into the right and left primary bronchi. The main role and job fulfilment of the trachea is to connect the pharynx or larynx to the lungs and allow a clear passage of air instructing to the lungs in order to complete respiration.
L.O.4.2 - The Structure and function of The Respiratory System.
Introduction.
Above is a diagram of the Respiratory system. Our respiratory system plays a Major part in how we live and also effects how well we exercise. In this essay I will be exploring the main structures and function of the Respiratory system, outlining each individual section found within and looking into how, what and why they do their specific tasks.
Respiration can be divided into two processes;
· External respiration
· Internal respiration
External respiration involves the movement of gases into and out of the lungs, supplying oxygen to our blood stream and the exchange of gasses between the lungs and the blood know as pulmonary diffusion.
Internal respiration includes getting oxygen to the body’s cells, exchanging oxygen and carbon dioxide in the cells and removing carbon dioxide and waste from the body
Below is an introduction to the respiratory system, outlining the structure of each component.
· Breathing.
The primary function of the respiratory system is to supply the blood with oxygen in order for the blood to deliver oxygen to all parts of the body. The harder we work the harder and faster we breath and so when exercising more blood is needed for our working muscles. The respiratory system does this through breathing. When we breathe, we inhale oxygen and exhale carbon dioxide. This change of gases is the respiratory system's way of getting oxygen to the blood. “The respiratory system exchanges carbon dioxide accumulated in the blood for oxygen in the airways. Inhaled air is taken into the lung, and after gas exchange, carbon dioxide is exhaled.” (Cheers, Gordon et al. The Human Body Atlas 2004)
The route by which air reaches our lungs is a complicated and essential process, below is a display of how this movement is performed taken from (Physical education and the study of sport - second edition – R J Davies et al. 1994)
‘’Air enters the breathing system through the nose and mouth. The nose is lined with a dense blood capillary network and ciliated mucous membrane. The air is warmed, filtered and moistened by this lining. Incoming air proceeds into the pharynx where it again is warmed and passed onwards onto the larynx, here it is further warmed filtered and moistened, the larynx contains a semi-cartilaginous flap called the epiglottis which when closed over the glottis, prevents food from entering the trachea. The trachea is a single airway extending from the larynx to the two diving bronchi. Air then passes down the trachea which approximately level with the fifth thoracic vertebra, divides into two short branching bronchi. The bronchi further subdivide into smaller branches called bronchioles. The epithelium which lines the trachea, bronchi and bronchioles contains goblet mucus cells and cilia. Cilia carry the mucus, with trapped dust and pathogens, to the back of the throat where it is swallowed.’’
Our breathing is deeply affected by physical activity and adapts in order to fulfil our bodies requirements. Below is an extract taken from (www.bbc.co.uk) explaining the different breathing processes and adaptations untaken when exercising.
‘’When the body is at rest we use our aerobic respiration.
During exercise the increase in our respiratory rates are brought about as a direct result of increases in our carbon dioxide and blood acidity levels. We breathe harder and deeper and the heart beats faster to get oxygen to the muscles.
Glucose + oxygen → energy + water + carbon dioxide
When exercising to an extremely hard fast pace, the heart cannot supply enough oxygen to the working muscles, it is here where Respiration becomes anaerobic.
Glucose → energy + lactic acid’’
The Lungs.
The lungs are two thin-walled elastic Spongy, saclike respiratory organs in the chest cavity which, together with the heart, work to remove carbon dioxide from the blood and provide it with oxygen.
Below is a paragraph taken form www.daviddarling.com explaining the structure of the lungs.
‘’The left lung is longer, narrower, and has a smaller volume than the right lung it shares space in the left side of the chest with the heart. The right lung is divided into three lobes and each lobe is supplied by one of the secondary bronchi. It has an indentation, called the cardiac notch, on its medial surface for the apex of the heart. The left lung has two lobes.’’
The lungs are soft and spongy because they are mostly air spaces surrounded by the alveolar cells and elastic connective tissue.
From the above statement collected from the before source we can conclude that our lungs hold a complex and important structure. Like wise its function, roles and responsibilities are essential and the following quotation taken from (www.chiff.com/health/lungs.) helps us to understand this.
‘’The main job of the lungs is to take oxygen from the atmosphere and put it in the bloodstream, while simultaneously taking carbon dioxide out of the blood stream and ejecting it in to the atmosphere.’’
The lungs perform this vital role by contracting and expanding, a job performed by the diaphragm muscle.
As we breathe in and out, the lungs inflate and deflate with air, taking oxygen into the body and expelling carbon dioxide from the body.
The diaphragm, in turn, receives signals from the brain telling it when to speed up (while you are running or exercising) or when to slow down (while you are at rest or sleeping).
When the diaphragm contracts, the lungs are pulled downwards, and their capacity is increased, which pulls air in. The diaphragm then relaxes, and whatever oxygen was not absorbed by the body, along with the carbon dioxide being ejected by the body, is allowed to leave the lungs.
In addition to providing the body with oxygen-rich blood, lungs are partially responsible for acting as a protective cushion for the heart which they almost completely surround.
The lungs are also important in the body's defence against infection and other harmful environmental factors. Inhaled particles or infectious agents pass through the mouth or nose and lodge in the lungs.
Mucus, a sticky fluid produced in the lungs, can trap these inhaled agents and aid the lungs' protective white blood cells in the engulfment and destruction of bacteria and other harmful materials. The cilia beat with a rhythm fast enough, and a force sufficient enough, to propel mucus and cells up the airways to be coughed out or swallowed.
On its journey to the lungs, air is drawn into the body and passes through many different structures;
Nasal passages.
(www.google.co.uk/imgres)
Air is drawn into the body via the nose. The nasal cavity is divided by a cartilaginous septum, forming the nasal passages. The interior structures of the nose help the respiratory process by performing the following important functions.
1. The mucus membranes and blood capillaries moisten and warm the inspired air
2. The ciliated epithelium filters and traps dust particles which are moved to the throat for elimination
3. The small bones known as chonchae increase the surface area of the cavity to make the process more efficient.
Larynx
Known commonly as the voice box is found within the neck of humans and is involved in the production of sound and also serves to protect the upper part of the trachea. The larynx houses the vocal folds and is shaped like a funnel, with walls of cartilage and a system of muscles. Air entering the larynx passes over the vocal chords and into the trachea. In swallowing, the larynx is drawn upwards and forwards against the base of the epiglottis, thus preventing entry of food.
The larynx is often divided into three sections: sublarynx, larynx, and supralarynx. It is formed by nine cartilages;
– the epiglottis
– thyroid
– cricoid
– arytenoid(2)
– corniculate (2)
– cuneiform(2)
All are connected to each other by muscles and ligaments and lined with mucous membrane.
(www.daviddarling.info)
The trachea.
The Epiglottis.
The epiglottis is flap of cartilage located in the throat behind the tongue and in front of the larynx. The epiglottis is usually upright at rest allowing air to pass into the larynx and lungs. When a person swallows the epiglottis folds backward to cover the entrance of the larynx so food and liquid do not enter the windpipe and lungs. After swallowing the epiglottis returns to its original upright position.
The Bronchi and Bronchioles.
Bronchus is a secondary branch of the airways that connect the lungs and the primary airway. The main bronchi branch directly from the trachea at about mid-lung, with the right main bronchus channelling air to the right lung and the left main bronchus directing air to the left lung. Each main bronchus nearly immediately branches into lobular bronchi, three in the right lobe and two in the left lobe. Bronchi become increasingly smaller as they branch deeper into the lungs. Rings of cartilage give larger bronchi rigidity and support. Smaller bronchi have fewer and thinner cartilage rings, and bronchioles, the tiniest of the bronchi, have thin walls of only smooth muscle tissue with no cartilage it is here that pulmonary diffusion occurs.
The Alveoli.
The alveolar walls are extremely thin and are composed of epithelial cells which are lined by a thin film of water, essential for dissolving oxygen from the inspired air.
Surrounding each alveolus is an extensive capillary network which ensures a smooth passage of oxygen into the pulmonary capillaries. It has been estimated that each lung contains up to 150million alveoli, providing a tremendous surface area for gas exchange. The alveoli walls also contain elastic fibres which further increase the surface during inspiration.
It is the job of the alveoli sacs to bring about new oxygen from the air just consumed to our bloodstream, it is here that the exchange if gases occurs, know as gaseous exchange.
· Gaseous exchange.
Respiration takes place in the mouth, nose, trachea, lungs, and diaphragm. They all play a major part in the gas exchange. Oxygen enters through the mouth and the nose. Oxygen then passes through the larynx. And then the trachea which then enters the chest cavity. In here, the trachea splits into two smaller tubes (the bronchi.). Each bronchus then divides again turning into the bronchial tubes. The bronchial tubes lead into the lungs where they divide into lots of smaller tubes, which join to tiny sacs called alveoli. Whist this is going on inside your body there is many effects you will see happening outside your body, some of these are; your ribs move upward and outwards, your diagram will expand (this will cause your lung size to increase) the pressure in your lungs will then fall. Your intercostals muscles then relax, you diaphragm then relaxes, your lungs then get smaller, and the pressure in your lungs then increases. Ready for another breath.
The Diaphragm.
The diaphragm muscle is a sheet of muscle essential for humans to breathe. It is a dome-shaped cavity near the lungs, between the thoracic cavity of the upper chest and the abdominal cavity of the stomach. The diaphragm muscle extends across the bottom of the ribcage and is the principle muscle of respiration. It is a muscle that contracts and relaxes as breathing takes place.
Below is a more in-depth understanding of the diaphragm as taken from (www.wisegeek.com)
‘’Composed of two main parts called the peripheral muscular part and the central aponeurotic part, the diaphragm muscle is a complex muscle consisting of fibres and tendons. The fibres of the peripheral muscular part converge to the central part. These fibres include the sternal, costal, and lumbar parts. The costal part descends from the ribs to compose the left and right parts of the dome that contract and expanding during respiration. The lumbar part attaches to the vertebrae in the back and connects to each side of the aorta.’’
Intercostal Muscles.
Picture showing the location of the intercostal muscles taken from (http://www.shapeandbuildmuscle.com/)
The intercostal muscles are found between the ribs and. and there are two kinds;
Internal intercostals
External intercostals
The internal intercostal muscles (found in the inside of the ribcage) extend from the front of the ribs, and go around back, past the bend in the ribs. These muscles work alternatively to lift and compress the ribcage in order to permit respiration.
The external intercostal muscles (situated outside of the ribcage) wrap around from the back of the rib. They consist of eleven muscles that envelop each side of the exterior of the rib cage.
The Pleurae is a thin, double-layered tissue which lines the walls of the lungs and heart. The pleurae helps the lungs to glide easily against the rib-lining tissues and the thoracic wall when the lungs take in air. Also, the pleural is essential to breathing because it serves as potential space. This important function helps the lungs form a vacuum which sucks in air from the atmosphere. In addition, its capability to stretch and divide the lungs into two compartments, a lower lung and a upper lung, allows other organs to move without interfering with respiration.
Bibliography.
· (Physical education and the study of sport - second edition – R J Davies et al. 1994)
· (Cheers, Gordon et al. The Human Body Atlas 2004)
· (The world of sport examined (second edition-2001) - Paul Beashel, Andy Sibon, John Taylor.)
· GCSE Classroom notes.
Olivia McCarthy.
L.O.5. Energy Systems
