In this topic, you will develop knowledge and understanding of the key body systems and how they impact on health, fitness and performance in physical activity and sport through the following content. The topic guide will be linked here.
The Musculo-skeletal
System
The Skeletal System
The skeleton serves five major functions:
1) Protection - some bones protect vital organs, for example, the cranium protects the brain.
2) Muscle attachment - bones are attached to muscles (thanks to tendons) and are used as levers for movement.
3) Blood cell production - platelets, red and white blood cells are produced in the spongey bone.
4) Storage of calcium and phosphorus - which is contained in the medullary cavity.
5) Movement - the joints in the skeleton works with our muscles to make movement.
These are the names of the bones you must know:
You must also know the regions of the vertebral column:
The Vertebral Column
The Vertebral column has 5 regions:
1) The cervical vertebrae, made up of 7 bones (your neck).
2) The thoracic vertebrae, made up of 12 bones (your upper back).
3) The lumbar vertebrae, made up of 5 bones (your lower back).
4) The sacrum, made up of 5 fused bones.
5) The coccyx, made up of 4 fused bones (your tailbone).
The sacrum and coccyx are both located in the pelvis.
Classification of Bones
There are four groups of bones you must know and be able to identify:
Long bones - long bones are used as lever arms in movement and the ends contain red blood marrow for red blood cells.
Short bones - short bones are weight bearing and are very light, strong and squat in shape.
Flat bones - flat bones are used for protection and have a broad surface area for muscle attachment.
Irregular bones - they have the same functions as the flat bones. However, these bones are specially shaped to perform particular tasks.
Classification and Movement of Joints
There are four types of joints:
1) Pivot (neck – atlas and axis which only allow rotation but is not mentioned in the video).
These joints have a ring of bone over a bone perfusion, around which it can rotate.
2) Hinge (elbow, knee and ankle which only allows forward and backwards movement).
3) Ball and socket (hip and shoulder and allows 360° movement); the rounded end of one fits inside a cup-sided ending of another bone.
4) Condyloid (wrist which allows forwards, backwards, left and right movement but not rotation).
Joints - Classification and Movement
Types of Movement
Abduction is a segment of the body moving away from the midline.
Adduction is the opposite of abduction and is when a segment is moving towards the midline.
Flexion is reducing the angle between two bones at a joint.
Extension is increasing the angle between two bones at a joint and hyperextension is increasing the angle at a joint beyond its normal range.
Circumduction is a cone of movement that doesn't include any rotation, occurs when flexion/extension movement is combined with abduction to adduction movements.
Rotation is any action where a body part is turned away or towards the midline.
The movements below are special to the ankle and are not mentioned in the video and are important to remember:
Dorsiflexion is the movement of the ankle so that the angle between the foot and shin is decreasing.
Plantarflexion is the movement of the ankle so that the angle between the foot and shin increases.
The Muscular System
There are three types of muscle:
Cardiac (muscle tissue that is found only in the heart), voluntary (in the skeletal system which are in antagonistic pairs) and involuntary (in blood vessels).
These are the names of the muscles you must know:
Muscle Fibres
There are three types of muscle fibres
- Type 1 (slow twitch fibres)
Type 1 fibres take a relatively long time to contract and have a good oxygen supply. They contract slowly but can work for long periods of time.
- Type 2a (fast twitch fibres which use oxygen)
Type 2a fibres contract quickly but tire easily. They have a limited oxygen supply.
- Type 2x (fast twitch fibres which use glycogen)
Type 2x fibres contract very quickly but tire easily and have no oxygen supply.
They would have a majority of type 1 slow twitch fibres, as they can work for longer periods of time.
What type of muscle fibres would a marathon runner have a majority of?
How The Skeletal System and The Muscular System Works Together
The skeletal and muscular system work together to create movement. Bones are used as lever arms. The bones of the skeletal system are attached to the muscles via tendons. Tendons are strong, connective tissues at the end of each muscle - these are attached to the bone.
Without the musculoskeletal system, movement would not be possible. Muscle contractions take place for movement of bones to occur. Within sport and physical activity, this movement is vital for effective performance. The quality and speed of movement - happening due to these two systems - can often impact an athlete's performance in sport. For example, a set shot in basketball allows the muscles and bones at the elbow (hinge) joint to collaborate resulting in movement to shoot the ball. This is an isotonic muscle contraction.
The Cardio-respiratory
System
How The Cardiovascular and Respiratory System Works Together
The Cardiovascular and Respiratory systems work together to allow participation in and recovery from physical activity and sport: oxygen intake into lungs transfers to blood and transports to muscles and removes CO2. This is especially effective after respiring anaerobically as there may be a build up of lactic acid to due to a debt of oxygen which may be paid back by increased amounts of oxygen intake.
The cardiovascular system works as a double circulatory system and serves three major functions:
1) Transporting oxygen, carbon dioxide and nutrients around the body
2) Helping blood clot
and
3)Controlling body temperature
The Systemic Loop and Blood Pressure
The systemic loop is as follows
Vena Cava → Right Atrium → Tricuspid Valve → Right Ventricle → Semi-lunar Valves → Pulmonary Artery → Lungs → Pulmonary Vein → Left Atrium → Bicuspid Valve → Left Ventricle → Semi-lunar Valves → Aorta
Blood Pressure
Systolic blood pressure is the pressure at which the ventricles are contracting.
Diastolic blood pressure is the pressure when ventricles relax.
Breakdown of Blood
1) Red blood cells - these carry oxygen to the working muscles to create energy.
2) White blood cells - these fight pathogens.
3) Plasma - this controls the viscosity of the blood.
4) Platelets - they clot open wounds.
Breakdown of Blood
Blood vessels and adaptations
Capillaries:
- Have a very thin wall which helps diffusion.
- Have a very small lumen.
- Are where gas exchange takes place.
Arteries:
- Have thick layer of elastic and muscular fibres.
- Have a small lumen.
Veins:
- Have a large lumen.
- Have a thin layer of muscle and elastic fibres.
- Have valves because of the low pressure and to prevent backflow.
Vasodilation, vasoconstriction and vascular shunting
Homeostasis is the regulation of conditions in the body. One of these conditions is temperature.
Vasodilation is the dilation of blood vessels, this allows the blood to get closer to the surface of the skin so that it can lose its heat. This happens when you're hot. Vasoconstriction, on the other hand, is the narrowing of blood vessels which does the opposite of vasodilation and keeps the heat of the blood in. This happens when you're cold.
Vascular Shunting is the redistribution of blood. Blood is directed away from inactive areas to active areas of the body. This is why performers are advised to eat two hours before competing, to avoid getting stiches in the stomach due to blood being transported to the working muscles.
Structure and Function of the Respiratory System
Structure and Function of the Respiratory System
Air is warmed, moistened and filtered as it travels through the mouth and nose, then into the trachea. The air then splits up and goes to either bronchus of either lung. It continues to travel through the bronchioles then into air sacs called the alveoli (where gaseous exchange takes place).
As you breathe in, the intercostal muscles of the rib cage and the diaphragm contract to increase the volume of the chest. When you breathe out these roles swap to push out the air.
Structure and function of the alveoli for gaseous exchange
-Large surface area and its own network of blood let it exchange gases at a larger rate.
-Moist Lining (moist with mucus) allows gases to dissolve before diffusing.
Vital Capacity and Tidal Volume
Vital Capacity is the greatest volume of air that can be taken in. Whereas tidal volume is the amount of air inhaled at a normal breath. When participating in physical activity, tidal volume increases because of the demand of oxygen.
Aerobic and Anaerobic Exercise
Anaerobic respiration is the process of producing cellular energy without oxygen. This is why anaerobic respiration occurs when short outbursts of movement take place (like in a sprint). Whereas, aerobic respiration is the process of producing cellular energy with oxygen. Aerobic respiration produces energy which can be used for a longer amount of time (like in a long distance event).
Aerobic Respiration:
Glucose + Oxygen → Carbon Dioxide + Water + Energy
Fat + Oxygen → Carbon Dioxide + Water + Energy
Anaerobic Respiration:
Glucose → Lactic Acid + Energy (a small amount)
Fat is used as an energy source for aerobic activity (that's the reason why long distance runners are usually ectomorphs as they use their fat sources).
Carbohydrates are a source for both anaerobic and aerobic activity (that's why athletes may "carbo-load" in order to increase the amount of Glycogen in the muscles). Carbohydrates are a source for both anaerobic and aerobic activity (that's why athletes may "carbo-load" in order to increase the amount of Glycogen in the muscles)
Carbohydrates are converted into glucose.
which can be used as a fuel in energy production.
Short-term Effects of Exercise
Short-term effects are those that take place up to 24 to 48 hours.
Effects on the Cardiovascular System
There will be an increase in cardiac output and stroke volume.
Cardiac Output is simply the amount of blood the heart pumps out per minute.
To work out Cardiac Output you use this formula:
CO = SV x HR
Stroke Volume, however, is the volume of blood pumped out of the left ventricle per heartbeat.
Effects on the Respiratory System
Tidal volume and rate of breathing increases.
Tidal volume is the volume of air inhaled at each normal breath. This will increase when doing physical activity because of the need for oxygen the working muscles require.
Effects on the Muscular System
Muscular fatigue and there will be lactate accumulation.
Lactic acid builds up in muscle fibres after respiring anaerobically. This also leads to an oxygen debt (that's why the muscles cramp up and fatigue)
Long-term Effects of Exercise
Long-term effects are those that take place over a period of regular training-this can be between six weeks and one year.
Effects on the Cardiovascular System
When exercising for a long period, your heart rate decreases. This means your heart will be stronger and you will recover faster.
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Recovering quicker means that there would be less chance of getting cramps or muscle fatigue, as there would be no build up of lactic acid as your body will be able to repay the oxygen debt more efficiently.
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Your heart will reach its maximum cardiac output. Reaching your maximum cardiac output means your heart will work more systematically as it can transport the most amount of blood possible.
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Exercise leads to an increased size/strength of heart, increased capillarisation, increase in a number of red blood cells and a drop in resting blood pressure due to the more elastic muscular wall of veins and arteries.
Effects on the Respiratory System
Partaking in exercise benefits the respiratory system in the following ways:
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It increases the lung capacity and vital capacity. This means the intake of oxygen done by the lungs increases.
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It also strengthens the intercostal muscles (between your ribs that allow your lungs to take in the greatest amount of air).
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Your diaphragm strengthens as well, as it contracts (and relaxes) at a faster rate when doing physical activity.
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It also increases the number of alveoli which enhances the rate of gaseous exchange
Effects on the Muscular System
Physical activity affects the muscular system in the ways listed below:
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After working out your muscles over a long period of time, muscular hypertrophy takes place (the opposite of muscular atrophy which may happen if you live sedentarily).
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It also strengthens tendons because of using them repetitively.
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Muscular endurance will increase (again because of using them repetitively).
Effects on the Skeletal System
Exercise affects the skeletal system in the following ways:
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Increases bone density. This decreases the risk of osteoporosis which is a medical condition in which the bones become brittle and fragile from loss of tissue.
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Exercise also increases the strength of the ligaments, this then decreases the risk of an injury.