Ben's BTEC blog: BTEC Sport level 3 - Principles of anatomy and physiology in Sport

BTEC Sport - Anatomy - Muscle Groups

You should have the second part of assignment 1.2 on your blog a powerpoint that EXPLAINS the function of the muscular system and the different fibre types. The final part of this assignment requires a more in depth analysis of the muscular system and fibre types. You must:

ANALYSE the structure and function of the muscular system and different fibre types and DISCUSS with reference to the structure and function of each fibre type, why a games player needs a balance of all 3 to ensure optimal performance. Give clear sporting examples where appropriate. D1

Answer - Slow Oxidative Fibre
An athlete can’t gain more fibres, but can train them, however training does damage them, and they grow back bigger and thicker. In the human body we would see that the skeletal muscles are made up of bundles of muscle fibres, which, when stimulated to contract help produce movement. The nature of the movement depends on the proportion of different fibre types.
“The distinctions of the fibre types seem to influence how muscles respond to training and physical activity, and each fiber type is unique in its ability to contract in a certain way. 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.” (www. sportsmedicine.about.com)

In the human body there are three main types of muscle fibres. We have slow oxidative fibre. they contract very slowly. The myelin sheath of the motor unit stimulating the muscle fibre is not as thick as that of the fast twitch unit, and this reduces the amount of insulation, slowing down the nerve impulse. Slow twitch do not contract with much force. Having said this, they can cope with bouts of prolonged exercsies.

These fibres contain a large number of mitochondria and Myoglobin, hence their red colour. They manufacture and split ATP at a fast rate by utilising both aerobic and anaerobic metabolism and so produce fast, strong muscle contractions, although they are more prone to fatigue than type I fibres. Resistance training can turn type IIb fibres into type IIa due to an increase in the ability to utilise the oxidative cycle.

Slow twitch contain many bloody capillaries and generate ATP by the aerobic system, and these fibres use oxygen and fat.” (www.isokinetics.net/advanced/musclefibertypes )
These types of muscle fibres are more suited to long distance runners as they take a long time to fatigue and the rich blood supply allows blood to reach the working muscles. They are adapted to low intensity aerobic endurance work and are generally employed at the beginning of exercise.

Examples = Endurance running, cycling, swimming and skiing.

Answer - Fast Oxidative Glycolytic fibre
These fibres have a thicker myelin sheath stimulating the muscle fibre so it can contract more quickly and with more force. this fibre type can produce energy both aerobically and anaerobically by breaking down carbohydrate to pyruvic acid, but far more suited to aerobic respiration, which means it can release energy very quickly. the rapid build up of lactic acid comes from this. Lactic acid is a by product of anaerobic respiration. This lowers the PH and has a negative affect on enzyme action, causing the muscle fibre to tire quickly.

They are intermediate fast twitch fibres. This is because they use both aerobic and anaerobic metabolism almost equally to create energy which is needed to carry out movements.

This type of fibre is more suited to team and game players, as its in between a blend of type 1 and 2b so fibres will perform in situations where an athlete may be jogging. For example in football however if the athlete receives the ball and sprints towards the goal, the fast twitch fibres also allow this.
They use carbon dioxide and oxygen and this type can produce energy both aerobically and anaerobically by breaking down carbohydrate to pyruvic acid, however it is far more suited to anaerobic respiration, which means it can release energy very quickly.’ (Class notes) The rapid build up of lactic acid causes this muscle fibre to fatigue quickly, but not as quickly as type 2b. “They are red in colour, and have a high capacity for generating ATP by oxidation, and Split ATP at a very rapid rate and, hence, high contraction velocity.” (www.isokinetics.net/advanced/musclefibertypes)
Answer - Fast Glycolytic fibres

These muscle fibres are also very quick to contract and can exert a large amount of force. They rely heavily on anaerobic respiration for releasing energy as they have very few mitochondria. This means energy is released very rapidly but the muscle fibre is quick to fatigue.

Energy is released very rapidly into the body and the working muscles causing the muscle fibre to fatigue quickly. ‘Suited to shorter duration exercises, 10 seconds and under on average, and perfect for power athletes’ (class notes) or for example more specific in a sport a rugby tackle, a dive off the blocks in swimming or a hit in hockey. These fibres cause a longer recovery time as the bodies energy systems and muscles are working extremely hard for a short period and suited to purely anaerobic performers, without the use of oxygen.
“They adapt to high-intensity anaerobic exercise involving explosive or powerful movements, but are increasingly employed as fatigue sets during low-intensity endurance work.” (BTEC Sport Level 3, Mark Adams et al 2010)
Sporting Examples
Slow Twitch -
Marathon running - 20k, 10k, 5k.
Long distance swimming
Downhill skiing
Long distance cycling
Fast Oxidative Glycolytic
Sports games e.g.-
Football
Rugby
Hockey
Netball
Athletics - 800M, 1500M & 3000M
Fast Glycolytic fibres
100M
200M
300M
400M
Weightlifiting - clean and jerk, cleans, squats, bench press
Shot putt, javelin, hammer throw
Gymnastics - Vaulting
BIBLIOGRAPHY
www. sportsmedicine.about.com
Class notes
www.isokinetics.net/advanced/musclefibertypes
BTEC Sport Level 3, Mark adams, R.Barker,C.Lydon,C.Mulligan,P.phillippo,L.Sutton. Essex, 2010.

Yr 12 Principles of Anatomy & Physiology Unit 1

Assignment 1:3

Describe the structure and function of the CV system.

• Produce detailed diagrams of the CV system (Heart &blood vessels)

• Describe the function of each structure identified. (What each structure does)

The Cardio Vascular system is made up of the heart, blood vessels and blood. It is the major transport system in the body. It carries food, oxygen and all other product to tissue cells. It also takes waste products and carbon dioxide away. Oxygen is sent around the body to the bodies tissues, while carbon dioxide is carried from cells to the lungs for excretion.

Functions of each structure

Right Atrium:

The Right Atrium is larger than the Left Atrium but has thinner walls. The Right Atrium has two major veins. These return blood to the heart from all parts of the body. The ‘Superior Vena Cava’ returns the de-oxygenated blood from the upper part of the body and the ‘Inferior Vena Cava’ returns the de-oxygenated blood from the lower part of the body. (Adams et al, 2010).

Left Atrium:

The Left Atrium receives blood from our Veins. The blood received from the lungs has been oxygenated. The oxygenated blood that is collected in the Left Atrium is then pumped into the Left Ventricle through the Bicuspid Valve and is sent out around the body.

Right Ventricle:

The Right Ventricle receives blood from the Right Atrium. When the heart contracts, blood is forced through the valves into the ‘Pulmonary Artery’. The Pulmonary Semi lunar Valve is a three flap valve that stops the backflow of blood. The walls of the Right Ventricle are a little thicker than the Right Atrium.

Left Ventricle:

The chamber of the Left Ventricle has walls that are three times the thickness of the Right Ventricle. This is important because the oxygenated blood that it receives from the Left Atrium has to be pump throughout the body. The Bicuspid Valve closes and the blood is collected in the Left Ventricle.

Aorta:

The Aorta is the largest blood vessel in the body. The inner diameter of the Aorta is about one inch. (http://web.buddyproject.org/web019)

The Aorta carries oxygenated blood to every other part of the body. The Aorta receives its blood from the Left Ventricle.

Septum:

The Septum is a partition that separates the right and left sides of the Heart. There are two separate regions of the Septum. They are the Interatrial Septum that separates the Atriums and the Interventrial Septurm that separates the Ventricles.

Superior Vena Cava:

The importance of the Superior Vena Cava is to return blood back to the Right Atrium from the upper part of the body. It is one of the largest veins in the body.

Inferior Vena Cava:

The Inferior Vena Cava is important for carrying the blood back to the Right Atrium from the lower part of the body.

Pulmonary Arteries:

The Pulmonary Arteries carry the blood from the Right Ventricle to both of the lungs. There the blood is oxygenated and sent to the Left Atrium in the heart.

Pulmonary Veins:

The Pulmonary Veins carry the oxygenated blood back to the Left Atrium in the heart.

Arteries

The arteries are elastic, muscular tubes that carry the blood from the left ventricle of the heart to the capillaries. They have two major properties. These are elasticity and contractility. They have thick walls to be able to carry blood at high speeds at high pressure. They have smooth muscle surrounding them which enable their diameter to increase and decrease when required. They are very deep, apart from at the region where a pulse can be taken. These vessels branch into smaller arterioles that ultimately deliver the blood to capillaries where oxygen and nutrients are found.

Arterioles

This has thinner walls than arteries. They control the blood distribution by changing their diameter. During exercise, muscles need more blood to flow in order to get oxygen to the muscles. To allow this, the diameter leading to the muscle dilates. Therefore – Arterioles are mainly responsible for controlling blood flow to the capillaries.

Capillaries

These form an extensive network that connects arteries and veins. They are the smallest blood vessel of all, being thin and narrow. They are essential to the vascular system. This is because they bathe the tissues of the body with blood and allow diffusion of oxygen and nutrients which are needed by the bodies’ cells to function.

Capillaries that surround muscles ensure the muscle gets oxygen and nutrients which are needed to produce energy. They are only one cell thick, therefore allowing nutrients, oxygen and waste products to be moved. The number of capillaries can be increased as a result of frequent and appropriate training. Training at high altitude can help this.

Veins

Veins facilitate venous return. This means the return of deoxygenated blood to the heart. They have thin wall and have a relatively large diameter. This is appropriate, because by the time blood gets into the veins, it is flowing slowly and has little pressure. Working muscles push the thin walls of the vein helping the veins squeeze the blood back to the heart. As muscle contractions can be intermittent, there are a number of pocket valves, preventing any backflow if a muscle relaxes at any point. Veins are close to the surface and can be seen under skin if they are being used regularly.

How blood is carried around the body to working muscles

1. Heart pumps blood under pressure into arteries

2. Artery walls are made of smooth muscle and elastic tissue. They stretch when blood is pumped. Smooth muscle contracts, forcing blood along

3. Artery branches into smaller tubes called arterioles

4. Arterioles branch into tiny tubes called capillaries. Their thin walls allow oxygen and nutrients to pass from blood into cells. Carbon dioxide and other waste products pass into the blood.

5. Waste filled blood flows into venules

6. From Venules, blood flows into veins, then to the heart.
This happens repeatedly.

(Adams et al,2010)

Bibliography;

· http://web.buddyproject.org/web019/web019/bvessels.html

· OCR BOOK 2010 – Adam et al, 2010.

· Class notes

· Picture from Google images

Ben Jenkins 12AM

3.2 functions of cv system detailed