exam p.e.

Function of the skeletal system:

• Protects the body’s organs. Ribs and sternum – heart and lungs. Cranium – brain. Pelvic – intestines.

• Allows movement through the use of joints and muscle attachment.  sports would be unable to play if we were unable to use any of our muscles to move 

• Helps formation of blood cells. Platelets, red blood cells and most white blood cells are produced in the bone marrow.

• Stores minerals. Bones store calcium and phosphorus. These minerals are necessary to keep bones healthy.

Classifications and functions of bones

• Long bones: longer in length than in wide, they act as levers, allowing us to move.

• Short bones: box-shaped bones, they are as long as wide.

• Flat bones: these bones are normally flat, thin and curved. They give protection and a large surface area for muscle attachment.

• Irregular bones: used for protection and attachment. (other bones that don’t fit in any description are irregular).

bones vertebral column

Cervical vertebrae: 

• First vertebra is called atlas → supports the weight of the head and allows us to nod our heads up and down.

• Second is the axis → shakes our heads.

• Third is the cervical vertebrae → allow muscle attachment, providing the most movement with the vertebral column.

Thoracic vertebrae: No movement, protect heart and lungs, attach and support the rib cage.

Lumbar vertebrae: Biggest individual vertebrae

• Support body weight

• Muscle attachment

Sacral vertebrae: vertebrae are fused together –> sacrum

• Transmit body weight to pelvis

Spine’s movements:

• Flexion (bending towards)

• Extension (bending forwards)

• Lateral flexion (bending sideway)

• Rotation (twist and turning)

Vertebral column in sport

• Movement of the head to the aid technique by cervical vertebrae.

• Protection of heart and lungs by thoracic vertebrae.

• Muscle attachment to allow flex, extend or rotate as required by their technique.

• Weight bearing for the sprinter by the sacral vertebrae.

Tendons: attach muscles to bones.. They are flexible (flexion and extension). 

Ligaments: are tough, elastic fibres that link bones to bones.  Joints are classified into types depending on the amount of movement that can be carried

Cartilage: prevents the ends of bones rubbing together at the joint.

Movement at joints

neck –> atlas and axis

elbow –> humerus, radius and ulna

knee –> femur, tibia, patella

ankle–> tibia, talus, fibula

hip –> ilium, the ischium, and the pubis, femur

shoulder –> Humerus and scapula

wrist–> Radius, scaphoid, lunate and triquetrum

Muscular and physical activity

Muscles are involved in every movement in your body. It is a special type of tissue made up of fibres that contract and relax

Classification of muscles

• Voluntary muscles → attached to bones and they work whenever we want them to.

• Involuntary muscles → found on the walls of the internal organs and they contract in waves. It works without you consciously controlling it, or even being aware of it.

• Cardiac muscles → special type of muscle that forms the walls of the heart chambers. It contracts without conscious thought or effort. It doesn’t stop and it never tires. When it contracts it pumps blood out of the heart and around the body.

In an antagonistic muscle pair as one muscle contracts the other muscle relaxes or lengthens. The muscle that is contracting is called the agonist and the muscle that is relaxing or lengthening is called the antagonist.

fibre types

Muscle twitch fibres occur in different proportions in different people. This proportion is mainly to do with the genes you inherit but can be altered by training.

There are 2 main types of muscle fibres:

• Slow twitch muscle fibres → small in size. These fibres take a relatively long time to contract.

• Fast twitch muscle fibre→ large in size, contract quickly and powerfully.

Slow twitch muscle fibres or Type I muscle fibres. → 60%

• Have a good oxygen supply because they have large amounts of myoglobin, mitochondria and have a good capillary network.

• They contract slowly, work long periods → aerobic

Fast twitch muscle fibres or Type II muscle fibres → 40%

• Limited oxygen supply → anaerobic

• Contract quickly and powerfully,but tire easily

• Type IIa fibres are mixed with type IIx, with properties of each. With appropriate training it is thought that these muscle fibre types can be adapted to either be endurance or power.

• Type IIx fatigue easily as they don’t have the myoglobin, mitochondria or large capillary network of slow twitch fibres and type LLa, therefore they would be good for events requiring speed or large amounts of force.

Cardiovascular system

The heart

It works continuously throughout our lives. In an average lifetime it can beat over three billion times.

Average heart rate: x (number of minutes a day) x (number of days in a year). If we exercise it beats more.

The heart is made up of 4 chambers;

The left and right atrium (top) receive blood into the heart and pass it on to the ventricles when they contract. 

The left atrium receives oxygenated blood from the lungs through the pulmonary vein and the right atrium receives deoxygenated blood from the body through the vena cava. 

The left and right ventricle (bottom) receive blood from the atria above them; once they have received the blood they contract to force the blood out of the heart.

The left ventricle has a thicker muscular wall because it has to do the most work; it is from here that the blood is pumped out of the heart via the aorta to the rest of the body. 

Aorta → artery

The right ventricle pumps blood as far as the lungs, via pulmonary artery to pick up oxygen.

The 3 valves left are flat. Allow blood to flow one way, emergency doors, let the blood out.

Oxygenated means that the red blood cells have collected oxygen from the lungs. Deoxygenated means that the oxygen that was being carried by the blood has been removed to release energy.

Tricuspid valve→ right side of the heart. It separates the right atrium from the right ventricle, allowing blood to flow from the atrium to the ventricle.

Bicuspid valve → left side of the heart. Separating the left atrium from the left ventricle. Allows blood to flow from the left atrium to the left ventricle, but not the other way.

Semi-lunar valves→ remaining valves, between the left ventricle and the aorta and the right ventricle. Allow movement of blood from the ventricles out of the heart, but once it has left, the blood is not allowed to return.

Septum → wall between the 2 sides of the heart,  left and right. The right side of the heart contains blood from the body that has been deoxygenated, whereas the blood on the left side of the heart contains oxygenated blood. If the blood were allowed to mix, the performer would receive a drop in the amount of oxygen being delivered to the muscles, so they would be unable to release as much energy for the physical work.

Double circulatory system

As the heart pumps, it circulates blood from the heart to the lungs and then back to the heart. Also it circulates from the heart to the rest of the body and back again. These 2 clear areas that are circulated are known as a double circulatory system.

Blood pressure

The blood moves through the blood vessels it exerts a force on the sides of the blood vessel it is travelling through. The strength of this force is your blood pressure. As the blood circulates further from the heart the force is reduced, so blood pressure decreases as the blood moves through arteries into the capillaries and then onto the veins. Blood pressure is measured, arterial blood pressure is used.

If your blood pressure is too high, it puts extra strain on your arteries, which may lead to heart attack or strokes

When ventricles contract, blood pressure is at its greatest. This is called systolic blood pressure. When the ventricles are filling, the blood pressure is lower. This is the diastolic blood pressure.

Heart rate

The number of times the heart beats per minute. Each time the heart beats, the ventricles contract, squeezing blood out of the heart into the lungs or the body. During exercise the rate of blood flow increases, so we can deliver oxygen more quickly to the working muscles and remove waste products, such as CO2. This means the performer can keep working at a higher level of intensity than when they are at rest. This increases the heart rate.

Stroke volume

When the ventricles contract, they do not empty completely of blood: only about 60% of blood is ejected. The muscles of the wall of the heart surrounding the ventricles become stronger so that when they contract they can do so more forcibly and therefore push more out of the heart. This is why stroke volume increases with regular exercise. The increase in stroke volume that is achieved through training also explains why fit performers tend to have lower resting heart rates than those who do not train.

Cardiac output

At rest we need about 5L of blood to circulate our bodies per minute, but this can change during exercise to 30 L of blood per minute to make sure we have enough oxygen.

Cardiac output= Stroke volume X heart rate

Vascular shunting

At rest there is enough blood circulating our bodies to carry out the functions the body needs. But the blood flow will vary, depending on the needs of the body. For example if we have just eaten there will be an increased need for blood flow for the digestive system. Although blood is still flowing, the amount available for the skeletal muscles is reduced. The problem will come if we need to exercise, because there won’t be enough oxygen delivered to the muscles. To overcome this problem:

• Increase cardiac output by increasing heart rate.

• Redistribute blood flow so that a greater percentage flows to the working muscles.

The process to allow us to redistribute blood is called vascular shunting and achieved through:

• Vasodilation

• Vasoconstriction

Blood vessels

Carry blood to and from all the living cells in the body. There are different types of blood vessels, each type has a specific job to do and it is structured differently so that it can do its job effectively.

Arteries:

• Carry blood away from the heart

• They are made up of the outside layer (tough), the middle layer (muscular) and the inner layer (smooth → blood to pass)

• Carry blood at a higher pressure because they take blood from the heart.

• They have thick muscular walls

• They pulsate: when the heart relaxes, the artery muscle contracts, pushing the blood forward.

• Carry oxygenated blood.

Veins:

• Main vein → vena cava

• Carry blood towards the heart at a low pressure

• Have valves

• Thin walls

• Larger internal lumen than arteries

• Carry deoxygenated blood

Capillaries:

• Blood goes from the artery into the vein via capillaries

• Carbon dioxide diffuses from the tissues into blood and oxygen.

• They are one cell thick and very fragile

• Blood cells pass through them one cell at a time.

Blood → made up of red blood cells, white blood cells, platelets and plasma. Adults have around 5.5L of blood.

• White blood cells: Responsible for seeking out and destroying infections. The white cells can slide through the walls of the blood vessel and attack bacteria. Keep performers healthy.

• Red blood cells: Contain haemoglobin → allows the transportation of oxygen.

• Plasma: liquid part of the blood. Made up of water. If plasma did not exist, solid cells would not be able to flow around the body, plasma gives other cells a ride.

• Platelets: maintaining the health of sports performers. Aid clotting

respiratory system

Components of the respiratory system

Air enters the body passing through the mouth and nasal passages. It is much better to breathe through the nose than the mouth because:

• The nose has a filter → remove dust particles of the air

• Warms the air → body temperature

• Moistens the air → it arrives at the lung saturated with water.

When leaving the nasal passages, the air flows into the larynx. After the larynx, the air goes through the trachea into the right or left bronchus. From the bronchi the air travels on to the bronchioles and finally on to the alveoli.

The gas exchange takes place in the alveoli. Gas exchange is the swapping of oxygen and CO2 due to the pressure gradients of each of the gases at the site of the exchange. The percentage of oxygen in the lungs is much higher than in the blood vessels.

Regular endurance training will result in an increase in the number of alveoli present in the lungs and an increase in the capillaries that are available to exchange gases with them.

An increase in alveoli means that the performer can diffuse more oxygen into the blood, provided that the alveoli have access to a blood supply for the exchange of gases.

Expiration and inspiration

The movement of the diaphragm and the ribs helps the movement of air into and out of the lungs.

During expiration the lungs slightly deflate when this happens the lungs do not take up as much room and so the ribs can move downwards and inwards, and the diaphragm can relax. This helps the lungs to expel some of the air inside them.

During inspiration, the lungs need to expand so they can hold more air, like a balloon being inflated. In order to make room for the lungs to do this, the diaphragm contracts and the ribs move up and out due to the contraction of the external intercostal muscles.

Although the lungs do not respond to regular training, for example they don’t increase in size; intensive exercise will fatigue the diaphragm and the external intercostal muscles so that they adapt and become stronger and more able to cope with the work a sports performer is doing. Due to the increased strength of these muscles, tidal volume can be increased.

LEVER SYSTEMS

All lever systems are made up of 4 components:

• Load → object requiring movement

• Fulcrum → joint around which the movement occurs

• Effort → muscular force used to move the object

• Levers → bones of the skeleton

1st – fulcrum is in the middle

2nd–> lever is in the middle

3rd –> effort is in the middle

• Movement in the sagittal plane about the frontal axis (somersaults)

• Movement in the frontal plane about the sagittal axis (cartwheels)

• Movement in the transverse plane about the vertical axis. (full twist in trampolining)

1. A Sagittal plane is a vertical plane that divides the body 

into the right and left sides.

2. The frontal plane is also a vertical plane but this divides the body into front and back.

3. The transverse plane is a horizontal plane that divides 

the body into upper and lower halves.

Vertical axis → runs through the body vertically from the top to the bottom

Frontal axis → runs through the body horizontally from the left to the right

• Sagittal axis → runs through the body horizontally from the back to the front.

• Beta blockers: slows heart rate, calms and steadies hands. Slows heart rate so slow that the heart may stop, causes tiredness.

• Anabolic steroid: repair body tissues after stress, muscle growth, less fatigue. Females develop males features, liver and heart damage, high blood pressure, aggression, acne.

• Narcotic analgesic: reduces pain or injuries. Causes nausea and vomiting, addiction, injuries, loss of concentration.

• Diuretics: rapid weight loss. Dehydration, nausea, dizziness, heart and liver failure.

Stimulants: reduces tiredness, increased alertness and endurance. Raise blood pressure, addiction, fatigue, aggression, anxiety, insomnia.

Peptide hormones:  increases red blood cells, increases oxygen and haemoglobin. Possible blood clots and cardiovascular problems.

components of fitness

• Cardiovascular fitness: can exercise for long periods of time

• Strength: amount of force a muscle can exert against a resistance

• Muscular endurance: is the ability to use the voluntary muscles many times without getting tired

• Flexibility: range of movement possible at a joint, how far we can stretch or reach.

• Body composition: percentage of body weight that is fat, muscle and bone.

• Speed: how fast we move.

• Reaction time: the time between the presentation of a stimulus and the onset of a movement (how far we react)

• Belance: the ability to retain the body’s centre of mass above the base of support.

• Agility: ability to change the position of the body quickly and control the movement.

• Coordination: the ability to use two or more body parts together.

• Power: the ability to do strength performances quickly.