BTEC Revision Guide Muscular System, Lecture notes of Law

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BTEC Revision

Guide

Muscular System

B1 Characteristics and functions of

different types of muscles

Pre Revision Post Revision Do you Understand the different types of muscles and their use in sport?  Cardiac – non-fatiguing, involuntary.  Skeletal – fatiguing, voluntary.  Smooth – involuntary, slow contraction

B2 Major skeletal muscles of the muscular system

Can you name the major skeletal muscles of the muscular

system?

 deltoids

 biceps

 triceps

 wrist flexors

 wrist extensors

 supinators and pronators

 pectorals

 abdominals

 obliques

 quadriceps

 hip flexors

 tibialis anterior

 erector spinae

 trapezius

 latissimus dorsi

 gluteals

 hamstrings

 gastrocnemius

 soleus

B3 Antagonistic muscle pairs

Movement of muscles in antagonistic pairs and their use in a variety of sporting actions?  Agonist  Antagonist  Synergist  Fixator

B1 Characteristics and functions of different types of muscles Type of Muscle Characteristics Examples Skeletal Muscle  Consciously controlled  They fatigue during exercise  Contract by impulses sent by the brain  Skeletal muscles contract which pull on bones to create movement Biceps Triceps Deltoids Gluteals Cardiac Muscle  Unconsciously controlled  Does not fatigue  Only found in the walls of the heart  Cardiac muscles help circulate blood through and out of the heart The walls of the heart Smooth Muscle  Unconsciously controlled  They are controlled by the nervous system  Control body functions such as: the movement of food and blood Arteries Veins Bladder Stomach Intestines B2 Major skeletal muscles of the muscular system

B The effects of exercise and sports performance on

the muscular system

Muscles Information Muscle Function Location Origin Insertion Activity

Biceps

Flexion of the Lower Arm at the Elbow Front of Upper Arm Scapula Radius Bicep Curl, Pull- Ups

Triceps

Extends Lower Arm Outside Upper Arm Humerus and Scapula Olecranon Process Dips, Press-Ups, Overhead Pressing

Supinators

Supinate the Forearm Top and Rear of Forearm Humerus Ulna Back Spin in Racket Sports, Spin Bowl in Cricket

Pronator

Pronate the Forearm Top and Front of Forearm Humerus Ulna Top Spin in Racket Sports, Spin Bowl in Cricket

Wrist Flexors

Flexion of the Hand at the Wrist Front of Forearm Humerus Metacarpal Bouncing a Basketball When Dribbling

Wrist

Extensors

Extension or Straightenin g of Hand at Wrist Back of Forearm Humerus Metacarpal Straightening of Wrist

Trapezius

Elevates and Depresses Scapula Large Triangular Muscle at Top of Back Continuou s Insertion Along Acromion Occipital Bone & all Thoracic Vertebrae Shrugging & Overhead Lifting

Deltoids

Abducts, Flexes and Extends Upper Arm Forms cap of shoulder Clavicle, Scapula and Acromion Humerus Forward, Lateral & Back-Arm Raises, Overhead Lifting

Pectorals

Flexes and Adducts Upper Arm Large Chest Muscle Sternum, Clavicle & Rib Cartilage Humerus All Pressing Movements

Latissimus

Dorsi

Extends and Adducts Lower Arm Large Muscle Covering Back of Lower Ribs Vertebrae and Iliac Cest Humerus Pull-Ups, Rowing Movements

B3 Antagonistic muscle pairs When a muscle contract, it exerts a pulling force on the bones to create movement. Under normal circumstances the muscles are in a state of partial contraction, ready to react to a stimulus from your nervous system. When a stimulus from the nervous supply occurs, muscle fibres work on an ‘all or nothing‘ basis – either contracting completely or not at all. When a muscle contracts, one end remains stationary (origin) the other moves (insertion). Muscles do not work on their own, they are assembled in groups and work together to create movement. They only act by contracting and pulling, they do not push. Many muscles work in antagonistic pairs. When one muscle contracts the other relaxes. The muscle that contracts is called the agonist and the muscle that relaxes is called the antagonist Example The biceps and triceps work together. When we bend the elbow (flexion) the biceps contract and the triceps relax Agonist = Biceps Antagonist = Triceps When we straighten the elbow (extension) the triceps contract and the biceps relax Agonist = Triceps Antagonist = Biceps

Antagonistic muscle pairs  Biceps – Triceps  Quadriceps – Hamstrings  Gluteals – Hip Flexors  Gastrocnemius – Tibialis Anterior  Wrist Flexors – Wrist Extensors  Pronators – Supernators  Abdominals – Erector Spinae Synergists: are muscles that work together to enable the agonist to operate more effectively. They work with agonists to control and direct movement by modifying or altering the direction of the pull on the agonist to the most advantageous position. For example, the soleus acts as a synergist to the gastrocnemius during plantar flexion of the ankle the latissimus dorsi acts as a synergist to the pectorals. Fixators: muscles stop any unwanted movement throughout the whole body by fixing or stabilising the joint or joints involved. Fixator muscles stabilise the origin so that the agonist can achieve maximum and effective contraction. Joint: Hip (ball & Socket) Joint Movement : Extension Agonist: Gluteals Antagonist: Hip Flexors Origin: Pelvis Insertion: Top of Femur Joint: Knee (Hinge) Joint Movement : Flexion Agonist: Hamstring Antagonist: Quadriceps Origin: top of Femur Insertion: Tibia, Fibula Joint: Ankle Joint Movement : Plantar Flexion Agonist: Gastrocnemius Antagonist: Tibialis Anterior Origin: Tibia, Fibula Insertion: Tarsals

B5 Fibre types Type Characteristics Sporting Examples Type I Slow Twitch  Contract Slowly  Low force of contraction  Aerobic  High resistance to fatigue Endurance events: Marathon Triathlon Long distance rowing Type IIa Fast Twitch  Contract fast  Medium force of contraction  Aerobic & Anaerobic  Medium resistance to fatigue Middle distance events: 400m Tennis Rally Combination punches Gymnastics floor routine Type IIx Fast Twitch  Contract very fast  High force of contraction  Anaerobic  Low resistance to fatigue Power events: 100m Shot-put Javelin Power lifting All or none law B6 Responses of the muscular system to a single exercise session Key Words Mitochondria: Found in the muscle and is the part of the cell where aerobic respiration takes place. Aerobic Respiration: Producing energy using oxygen, energy is released from glucose. (Aerobic activities are generally low intensity and endurance). Anaerobic Respiration: Producing energy without oxygen, energy is released from glucose. (Anaerobic activities involve high intensity and power). The muscular system works with the nervous system to bring about muscle contraction. Impulses are sent to the motor neurones. (nerves) The motor neuron is attached to a number of muscle fibres in the muscle. Together these are call a motor unit. The muscle fibres within the motor unit will be of the same type. When the motor neuron receives a signal to contract, all the fibres attached to the motor neurone will contract. This is called the all or none law. The force the muscle produces will depend on the amount of motor units stimulated to contract

B7 Adaptations of the muscular system to exercise

Response Explanation

Increased blood supply Blood carries oxygen. Oxygen is needed for energy. When we exercise there is an increase in demand for oxygen and glucose in the muscles, which is met by an increase in blood supply. Blood vessels expand or get wider to allow more blood to enter your muscles. This is called v asodilation. Blood flow increases significantly to ensure that the working muscles are supplied with the oxygen they need as well as to remove waste products such as carbon dioxide. Increase in muscle temperature When we produce energy for exercise it creates heat. The more you exercise or the harder you train, the more energy your muscles need. This results in more heat being produced. The amount of heat your muscles produce is in direct relation to the amount of work they perform. This principle is used in a warm-up which prepares your muscles for exercise by slowly increasing their temperature. Increased muscle pliability The warming of your muscles during activity makes them more pliable and flexible. Pliable muscles are less likely to suffer from injuries such as muscle strains. An increase in pliability will improve joint flexibility as warm and pliable muscles are able to stretch further. Lactate accumulation You may have experienced an uncomfortable burning sensation in your muscles during high intensity exercise. This is most likely caused by the build-up of lactic acid which is a waste product produced during anaerobic exercise. This build-up of acid in the muscle tissue will result in rapid fatigue and will impede muscular contractions if it is not removed quickly Microtears During resistance training such as weight training, your muscles are put under stress to the point that tiny tears occur in the muscle fibres. These micro tears cause swelling in the muscle tissue which causes pressure on the nerve endings and pain. Training improvements will only be made if the body has rest and time to repair these micro tears, making the muscle a little bit stronger than it was before. Delayed onset of muscle soreness (DOMS) Delayed onset of muscle soreness (or DOMS) is the pain felt in muscles 24–48 hours (typically) after taking part in strenuous exercise. The soreness usually occurs at least a day after exercise and can last up to 3 days. DOMS is caused by the micro tears that occur when you exercise, particularly if you are unaccustomed to the intensity of exercise. DOMS is often associated with exercises where eccentric muscle contraction has occurred.

Age As you get older your muscle mass will decrease. The onset of this muscle mass loss begins around the age of 50 and is referred to as sarcopenia. Muscles become smaller resulting in a decrease in muscle strength and power. Cramp Cramp is the sudden involuntary contraction of your muscle. The sensation of muscle spasm where you have no control of the tightening of the muscle fibres can be painful and can be prompted by exercise. The muscles of the lower leg are particularly susceptible to cramp during exercise. Cramp can last from a few seconds up to 10 minutes. There are a number of factors that can contribute to cramp. The most common one in sport is dehydration which can result in the inadequate supply of blood to the muscles, reducing the supply of oxygen and essential minerals. To prevent cramp, you should ensure that you drink plenty of fluid during exercise and sport, especially if the weather is hot. Stretching can also help to prevent cramp as this will lengthen the muscle fibres and improve muscle flexibility. BTEC – End of Unit Test (Muscluar System) (^56)

1. Label the Muscles 1-9 in the diagram. (10)

1 ____________________________

2 ____________________________

3 ____________________________

4 ____________________________

5 ____________________________

6 ____________________________

7 ____________________________

8 ____________________________

9 ____________________________

10 ____________________________

2. Name the three types of muscle and give an example of where they can be found in

the body? (3)

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3. Fill in the table below naming the muscle and its function? (7)

4. Fill in the table below filling in the missing antagonist pair (4)

Muscle Function Bicep Flexes the knee Gastrocnemius Extends the hip Abdominals Lateral flexion of the trunk Supinators 1 2 4 3 7 8 9 10

8. Usain bolt is a sprinter, what type of muscle fibres are required for his event. Give

three reasons why they are suitable? (3)

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9. Christine Ohuruogu is a 400m runner, what of muscle fibre type is most suitable for this event

give three reasons why they are important? (3)

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10. Mo Farah is an Olympic gold medallist in the 10,000m. Evaluate the importance of

all three muscle fibre types during a 10,000m race? (5)

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11. Muscles contract in different ways, describe and explain how the biceps are contracting in

the pictures? (6)

Holding the weight: ___________________________

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Downwards phase: ______________________________

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Upwards phase: ___________________________

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12. Describe an isometric muscular contraction and give a sporting situation when you

would see one? (3)

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13. Explain the difference between a synergist and a fixator? (2)

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14. Warming up is an important aspect of any sports or training session, explain the

responses to the muscular system when warming up? (5)

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Holding the weight Downwards phase Upwards phase

18. Explain how the musculo-skeletal systems work together to create movement? (8)

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Self-Assessment  You are now going to assess your work  Fill in any incorrect answers in Green pen  Give yourself a score below Self-Assessment Write a short post it note on your knowledge of the muscular system. What are your strengths and what are your weaknesses? 80 Post it