Skeleton
Assiment One Muscles
Muscles
Assiment 1.2 Muscle Fibers
Assessment 1.2
Assiment 1.3 and 1.4
The structure and function of the cardiovascular system
Heart
Image obtained from http://www.alabelleddiagramofthehumanheart.net/diagram-of-the-human-heart
The heart is the centre of the cardiovascular system, this muscle is found in the left-hand side of the chest beneath the sternum.
Its purpose is to pump oxygenated blood around the body and to deliver deoxygenated blood back to the lungs to exchange cardon dioxide for oxygen.
The heart is surrounded by a twin-layered sac known as the pericardium, pericardium fluid fills the cavity between the layers. This fluid prevents friction as the heart beats.
The heart itself is made up of 3 layers:-
- The epicardium which is the outer layer.
- The myocardium which is the middle layer and is the strongest layer and forms must of the heart wall.
- The endocardium which is the inner layer.
The heart is two pumps because the two chambers on the right side function separately than the chambers on the left side.
The chambers on the right side pump blood at low pressure through the pulmonary arteries, arterioles and capillaries, this is where gaseous exchange takes place. Here carbon dioxide passes from the blood into the alveoli and exchanges it for oxygen. This blood then returns to the heart but into the left side of the heart via the capillaries, venules and veins.
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When the left side of the heart is full of oxygenated blood, it contracts at the same time as the right side, acting as the high-pressure pump. It supplies the oxygenated blood via the arteries, arterioles and the capillaries to the tissue of the body like muscle cells. Oxygen moves into the cells and carbon dioxide is a waste product that is produced and is exchanged in the blood for the oxygen, the blood then returns to the right side of the heart where the process starts again.
Atria
The atria receives blood that is returning to your heart from either the body or the lungs and is located at the upper chamber of the heart.
The left atrium receives oxygenated blood from the left and right pulmonary veins while the right atrium receives deoxygenated blood from the superior and inferior vena cava.
Ventricles
The ventricles are the pumping chambers, They have thicker walls than the atria. The left ventricle pumps blood to the systemic circulation for the body while the right ventricle pumps blood to the lungs for gaseous exchange.
Bicuspid Valve
This is situated between the left atrium and the left ventricle and allows the blood to flow in one direction only. This is from the left atrium to the left ventricle.
Tricuspid Valve
This is located between the right atrium and the right ventricle and allows the blood to flow from right atrium to right ventricle.
Aortic Valve
Located between the left ventricle and the aorta its prevents back flow from the aorta into the left ventricle.
Pulmonary Valve
It is between the right ventricle and the pulmonary artery and prevents back flow from the artery.
Aorta
This is the body's main artery and it originates in the left ventricle and carries oxygenated blood to all parts of the body except the lungs.
Superior Vena Cava
This is a vein that receives deoxygenated blood from the upper body to empty into the right atrium of the heart.
Inferior Vena Cava
This is a vein that receives deoxygenated blood from the lungs to the left atrium of the heart.
Pulmonary Vein
This vein carry's oxygenated blood from the lungs to the left atrium of the heart.
Pulmonary Artery
This carry's deoxygenated blood from the heart back to the lungs, it is the only artery that carry's deoxygenated blood.
Blood Vessels
Blood vessels carry blood as the heart contracts through around 96,000 km worth of arteries, arterioles, capillaries, venules and veins.
The structure of these vessels depends on the function they are needed for. Blood flows through the arteries as a bright red because it is oxygenated, as it moves through the capillaries oxygen is taken from the blood and is replaced with carbon dioxide and when it reaches the veins the blood appears as blue.
Arteries
The arteries carry blood away from the heart and have two major properties : elasticity and contractility.
They have a thicker muscle wall because of the high pressure and speed. When the heart contracts the arteries expand to accommodate the extra blood, they do not need any valves because the pressure is constant.
It has a smooth muscle surrounding the arteries to enable them to increase and decrease as required.
Arterioles
The arterioles have thinner walls than the arteries to allow blood to go into the capillaries, the arterioles acts as a joiner between these two vessels.
The arterioles are responsible for controlling the amount of blood that go into the capillaries, this will depend on the amount and intensity of the exercise. If too much pressure is put into the capillaries they will split and cause bleeding.
Capillaries
The capillaries are an extensive network of vessels that surround themselves around cell and muscle tissue. The capillaries perform the exchange of oxygen and carbon dioxide to and from the tissue.
The capillaries are one cell thick to allow an easy exchange of gasses and nutrients. The pressure within the capillaries is greater than veins but less than the arteries and arterioles.
Venule
The venule is a joiner vessel between the capillaries and the veins. They have slightly thinker walls than the capillaries and are designed to help carry blood back to the heart.
They have a valve with stops back flow, this valve closes when pressure is decreases between beats.
Veins
The veins carry deoxygenated blood away from the body to the heart. The veins have a thicker wall but less than the artery's. The veins also contain a valve to stop back flow because of the low pressure and speed of the blood.
The veins are close to the surface and can be seen under the skin.
Reference
BTEC Level 3 National Sport Unit 1 by Louise Sutton.
The structure and function of the respiratory system
The respiratory system is responsible for providing oxygen and removing carbon dioxide.
The Lungs
The lungs are paired right and left, the lungs occupy most of the chest cavity.
They hang suspended in the cavity and straddle the heart. The left lung is smaller than the right lung.
Respiratory System
The lungs are paired right and left, the lungs occupy most of the chest cavity.
They hang suspended in the cavity and straddle the heart. The left lung is smaller than the right lung.
Respiratory System
Air is drawn from either the nasal cavity or through the mouth and it passes though several airways until it reaches the lungs. The airways are referred to as the respiratory tract, and is divided into two sections called the upper respiratory tract and the lower respiratory tract.
The upper respiratory tract includes the nasal cavity, mouth, pharynx and the larynx. The lower respiratory tract includes the trachea, bronchi and the lungs.
Nasal Cavity
There are two parts to the nose, the external nose and the internal nasal cavity.
When you breathe in, air goes through the nostrils and the nasal hairs act as a filter from dust, pollen and other fine foreign particles.
As it moves down the air is warmed and moistened before it is passes into the nasopharynx.
Epiglottis
This is a small flap which is found at the back of the tongue that closes the top of the trachea when you swallow to ensure food and drink do not enter the lungs.
Pharynx
This connects the nose, mouth and oesophagus, it is commonly known as the throat and is a small tube that measures 10-13cm long from the base of the skull to the sixth cervical vertebrae.
It is a passageway for food aswell as air, it has special adaptations to prevent choking when food or liquid is swallowed.
Larynx
It is a rigid wall of muscle and cartilage that contains the vocal cords and connects the pharynx to the trachea. It is commonly known as the voice box. It extends 5cm from the level of the third to sixth vertebra.
Trachea
Known as the windpipe, the trachea is 12cm long by 2cm in diameter. It contains rings of cartilage to prevent it from callapsing and it is very flexible. It travels down the neck in front of the oesophagus and branches into the right and left bronchi.
Bronchus
The right and left bronchi is formed by the division of the trachea, they carry air into the lungs. The right bronchi is shorter and wider than the left and is more common site for foreign objects.
By the time air reaches the bronchi it is warm and clear from most impurities and saturated with water vapour.
Once inside the lungs the bronchi divides into lobar trachea. There are three on the right and two on the left.
The lobar trachea then branch into segmental bronchi which divided again into smaller branching bronchi.
There are 23 orders of branching bronchial airways inside the lungs.
Lobes
Each lung is divided into lobes, the right lung has three lobes and the left lung has two.
Pleural membrane and cavity
The lungs are surrounded by membranes known as pleura. The cavity contains fluid that lubricates the pleural surfaces as the lungs expand and contract.
This prevents friction and keeping them airtight.
Alveoli
Air moves into the Alveoli where Gaseous exchange happens, this is where fresh oxygen is exchanged for carbon dioxide. The carbon dioxide is a waste product of the body.
Lung Volumes
Your respiratory rate is the amount of air you breathe in one minute. A typical 18 year old would take 12 breaths, this is around 6 litres of air that passes through the lungs.
But during exercise this can increase to 30-40 breathes a minute.
Control of breathing
There are two types of control:-
- Neutral control
- Chemical control
The ventral respiratory group controls the rhythem generation.
Chemical control are the continually changing oxygen and carbon dioxide percentages in the body and the sensors respond to the percentages. They are found in the medulla, aortic arch and the carotid arteries.
Assessment 1.5
Every movement and action our body does requires energy. This energy we collect from food sources, as the food is broken down the energy is taken and transported to the muscles where it will lay dormant until require. But because we constantly move it will not lay dormant for too long.
The body can function aerobically or anaerobically, movements that require sudden bursts of effort are powered by an energy system that does not require oxygen.
There are three main types of Energy Systems that our body uses and they are:-
- The ATP/PC System - used for actions that last 0-10 seconds long.
- The Glycolitic System (Lactic Acid) - used for actions that last 10 seconds to 2 minutes long.
- The Aerobic System - used for actions that last from 2 minutes onwards.
ATP/PC (ATP and Creatine Phosphate)
ATP consists of a base (adrenaline) and three phosphate groups, It is formed by a reaction between an adenosine diphosphate molecule and a phosphate.
ATP is an very versatile molecule that can be used for many things, the energy is stored in the chemical bonds in the molecule. When the bond is broken, energy is released. When the bond is made, energy is stored.
When the molecule is combined with water the last group splits off and energy is released.
The ATP/PC system is used for high intensity actions which last a short period of time but require a large amount of energy quickly. Such activities will include 100 meters sprint, jumping events and throwing events.
All of these include an explosive movement which is why it suits the ATP system.
Creatine Phosphate is an immediate energy system and is a high energy compound. When the high-energy bond in PC is broken the energy it releases is used to resynthesise ATP.
In the process ATP is usually made without the presence of oxygen.
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| Diagram showing the process and regeneration of the ATP/PC system. |
When the bond is broken ATP (adenosine tri phosphate) becomes ADP (adenosine di phosphate) as the compound looses 1 phosphate molecule. But the ADP gains a phosphate and then becomes ATP again.
Energy is used in order to make the muscle fibers contract. Energy is obtained by oxidation foods on the diet. Mostly carbohydrates and fats are good sources.
Carbohydrates are broken down into smaller and similar sugar called gloucose which if it is not immediatly required by the body will be converted into another sugar, glycogen and then stored in the liver and the muscles.
Fats are broken down to form free fatty acids.
When these substances are burned in the muscles ATP is formed. Then as ATP breaks down it makes the muscles contract.
Lactic Acid Energy System
This is a short term energy system that becomes effective as the ATP/PC system runs out of energy after around 10 seconds. This system is effective for events such as a 400 meter race or archery where the muscles will be working for a while under strain or over a continuous period of time, contracting.
The lactic acid system is also apart of the anaerobic process which means that it can only re-energize through food.
Anaerobic glycolysis begins to break down the liver and muscle glycogen stores when the ATP/PC system runs out of energy. Lactic acid is a by product of this process which limits energy production via this process.
Lactic acid is a limiting factor of the anaerobic system, It accumulates and diffuses into the tissue fluid and blood. If the substance is not removed by the circulatory system then the build up will cause the muscles to not work effectively and efficiently and begin to cause fatigue. It would cause a burning sensation in the muscles during intense exercise. During exercise the body does not switch between systems, energy is derived by all three systems. But the emphasis changes depending on the intensity of the activity.
It take around 45-60 minutes of rest before lactic acid removed from the system.
Aerobic Energy System
This is the long term energy system. If lots of oxygen is available as it is during everyday movements, glycogen and fatty acids break down to yield large amounts of ATP. This produces carbon dioxide and water as a by product. This does not affect the ability of the muscles.
Aerobic energy production occurs in the mitochondria of the cells and these are the power stations of the cells.
The production is slow to engage because it takes a few minutes for the heart to deliver oxygenated blood to the working muscles, long continuous exercise like a 1200 meter run or a marathon uses the aerobic energy system because those types of exercise are over a long period of time allowing for the oxygenated blood to reach the working muscles.
Amounts of ATP produced by each system
CREATINE PHOSPHATE ENERGY SYSTEM
ADP + CREATINE PHOSPHATE = ATP + CREATINE
LACTIC ACID ENERGY SYSTEM
GLUCOSE= 2 ATP+ 2 LACTIC ACID + HEAT
GLYCOGEN= 3 ATP+ 2 LACTIC ACID + HEAT
AEROBIC ENERGY SYSTEM
GLUCOSE + OXYGEN = 38 ATP + CARBON DIOXIDE + WATER + HEAT
FATTY ACIDS + OXYGEN = 129 ATP + CARBON DIOXIDE + WATER + HEAT
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