1. The Skeletal/Muscular System
Topic:Section 1B: Human Biology – The skeletal/muscular system, the senses and human reproduction
Main Topic Sub-topics
1B1 Skeletal system the role of the skeleton in support, movement and protection
function of bone
1B2 Muscular system muscles, tendons, ligaments and joints
function of muscle in relation to movement
On completion of this section, students should be able to:
OB24 identify the main parts of the human skeleton and understand that the functions are support, movement and protection.
OB25 locate the major bones in the human body including the skull, ribs, vertebrae, collarbone, shoulder blade, humerus, radius, ulna, pelvis, femur, tibia and fibula, using a diagram or a model skeleton.
OB26 understand the function of joints and muscles (including antagonistic pairs), tendons and ligaments, and the relationship between these and bones.
OB27 describe the general structure and action of different types of joints: fused, ball and socket and hinged, and identify examples of each: skull, shoulder, elbow, hip, knee.

2. Meet Charlie Why do we need a skeleton? Broken bones, x-ray
Find the bone on Charlie
Introduction the skeleton
It’s a good to start with locating the bones (a model is brilliant for this, with a diagram for reference) because the students can see where the bones are and by seeing they can determine the functions themselves with only a little prompting.
Ask the students what would happen without their own skeleton? Imagine you are out playing Hockey/soccer/hurling/football/rugby when your skeleton turns to jelly. Could you continue the game? What would happen to you? – stating that you turn into a blob usually gets a good effect.
Next introduce them to the skeleton – in this case Charlie.
Sit the group around in a semi–circle facing the skeleton – a model is the best way to do this but if there is not one available there are some very good websites available if there is broadband in the classroom (try
Ask has anyone ever had a x-ray or broken a bone – if so can you find that bone on Charlie and show it to the class?
Use this to start introducing the different names and locations of the bones including the skull, ribs, vertebrae, collarbone, shoulder blade, humerus, radius, ulna, pelvis, femur, tibia and fibula.
Most students actually like learning the latin names too e.g. sternum, scapula, patella etc as well as some extra bones.

3. Skull Shoulder Blade Collarbone Humerus Ribs Vertebrae Ulna Pelvis
Radius
Femur
When the introduction at the model has been completed work your way through the bones from head to toe on this slide – go to the next slide (a duplicate of this slide) this time with students having to guess the correct name before you will reveal it.
Tibia
Fibula

4. Skull Shoulder Blade Collarbone Humerus Ribs Vertebrae Ulna Pelvis
Radius
Femur
Black out the screen (ensuring all books are closed) and hand out a blank skeleton to the class and ask them to label it.
If the class are still unsure repeat this slide once more and then let them label their blank skeleton.
Correct as a group using this slide again.
Tibia
Fibula

5. Why do we need a skeleton?
Protection
Movement
Support
Remind students to think of the different bones we have just named and located on the previous diagram. Ask them was there anything in particular that stood out to them? Why do we need these bones? Why do we need our skeleton? What advantages does it have for our every day lives? Tell them to imagine what would happen without the different parts of their skeleton. Give the class time to figure out as many as these as they can on their own. If they get stuck give them some hints.
The spine? Why do they think we have a spine or skull or ribs or pelvis? What is located inside these bones? Is it of high or low importance to our lives? Thus these bones function in protection.
Support – remind the students of cell biology – cell walls in plants. Do plants have a skeleton? Why do we have a skeleton? Without our skeleton we would be a Blob on the floor – Can anyone think of an animal that does not have a skeleton of sorts? What bones do they think are involved in support?
Movement – we need our bones for strength and support but we also need them for movement. Our muscles are key to our movement but they need something to work against – our bones. Joints occur where bone meets bone – some of these allow for movement. We will cover these in detail during the next few classes.
To remember the functions think PMS – this should get a good giggle.

6. Movement and joints
OB27 describe the general structure and action of different types of joints: fused, ball and socket and hinged, and identify examples of each: skull, shoulder, elbow, hip, knee.
In this lesson the students will be introduced to joints. They must be able to understand that there are 2 main classifications of joints (moveable and immoveable) both of which are very important to the functions of the skeleton.
This is where the students get an opportunity to share their knowledge with the class. Some may have already covered this material in primary school or will have heard their mother or granny saying they were cooking a joint for dinner.

7. Joints occur where bone meets bone 2 main divisions of joints:
Immovable
Moveable
If a joint occurs where bone meets bone can anyone tell me where I can find a joint or locate one on the skeleton (swing arm around in the air whilst saying this or bend your knee)?
Suggest to class that there is always movement where bones meet and take a vote on whether this is true or false.
If the students are taking the side of false then ask them how many bones they are born with (approx. 300) and how many bones they will have as an adult (206). Retake the vote.
Double jointedness or hypermobility as is the correct term may also be brought up by students. This will be covered in the last slide in this lesson.

8. Immovable fused joint No movement Where? – skull, pelvis
Ask has anyone ever held a baby? Why did they need to be so careful around the head – remind students that when we are born our skull is made up of plates which grow and fuse together as we get older – get students to look at the skull of the class skeleton.
Does anyone in class know we have a tailbone? This is an example of another fused joint (also an example of a vestigial organ).

9. Moveable E.g. synovial joint
This is extra information and is not required but it will help students to better understand movement.
Compare the moveable joints to a bike and remind students how a bike must be oiled – thus so must our body have something in the joints to lubricate them – a fluid called synovial fluid.
But this fluid doesn’t stop our bones from rubbing off each other. Hand a student 2 pieces of chalk and get them to rub the ends together. Ask the class to comment on what is happening. Ask them is there any way we could have prevented this? – Introduce the idea of cartilage – between certain bones, discs in back, in our ears (tell students to bend the top of their ears, explain how it used to be fashionable to get this pierced (“crunchy bit”), the bendy bit in our nose (be careful to differentiate form the bone at the top) –gristle in sausages and burgers.

10. E.g. hinge joint Movement in one direction only Where?
- Elbow and knee
Introduce the joint by stating that some joints in our body allow movement similar to that of hinges in the door. Ask students who have a metal pencil case to open and close the cases. Also get other students to open and close the door to the classroom, windows, cupboards – as many different hinges as you can think of.
Next ask students how many directions could the door etc. move in?
Then ask the students to think of any places where bone meet (joints) in their body which have this sort of movement. If they need a hint start flexing your fingers.
When the students start to bend their knees (and hear cracking and popping) they are also likely to ask about cracking joints, knuckles and their links to arthritis.
Here is some useful information from
If you've ever laced your fingers together, turned your palms away from you and bent your fingers back, you know what knuckle popping sounds like. Joints produce that CRACK when bubbles burst in the fluid surrounding the joint. Joints are the meeting points of two separate bones, held together and in place by connective tissues and ligaments. All of the joints in our bodies are surrounded by synovial fluid, a thick, clear liquid. When you stretch or bend your finger to pop the knuckle, you are causing the bones of the joint to pull apart. As they do, the connective tissue capsule that surrounds the joint is stretched. By stretching this capsule, you increase its volume. And as we know from chemistry class, with an increase in volume comes a decrease in pressure. So as the pressure of the synovial fluid drops, gases dissolved in the fluid become less soluble, forming bubbles through a process called cavitation. When the joint is stretched far enough, the pressure in the capsule drops so low that these bubbles burst, producing the pop that we associate with knuckle cracking.
It takes about minutes for the gas to redissolve into the joint fluid. During this period of time, your knuckles will not crack. Once the gas is redissolved, cavitation is once again possible, and you can start popping your knuckles again.
As for the harms associated with this habit, according to Anatomy and Physiology Instructors' Cooperative, only one in-depth study regarding the possible detriments of knuckle popping has been published. This study, done by Raymond Brodeur and published in the Journal of Manipulative and Physiological Therapeutics, examined 300 knuckle crackers for evidence of joint damage. The results revealed no apparent connection between joint cracking and arthritis; however, habitual knuckle poppers did show signs of other types of damage, including soft tissue damage to the joint capsule and a decrease in grip strength. This damage is most likely a result of the rapid, repeated stretching of the ligaments surrounding the joint. A professional baseball pitcher experiences similar, although obviously heightened, effects in the various joints of his pitching arm. But assuming you haven't signed a multimillion dollar contract to constantly pop your knuckles, it hardly seems worth the possible risk to your joints.
On the positive side, there is evidence of increased mobility in joints right after popping. When joints are manipulated, the Golgi tendon organs (a set of nerve endings involved in humans' motion sense) are stimulated and the muscles surrounding the joint are relaxed. This is part of the reason why people can feel "loose" and invigorated after leaving the chiropractor's office, where cavitation is induced as part of the treatment. Backs, knees, elbows and all other movable joints are subject to the same kind manipulation as knuckles are.

11. E.g. ball and socket joint
Movement in all directions
Where?
– shoulder and hip
Get students to stand at a safe distance form anyone or anything that could cause damage to themselves and swing their arms around or sit on the ground with bent knees and rotate their legs. Ask in what way they could move their limbs?
It is also a good idea to have a model ball and socket joint – egg cartons and ping pong balls will do. This is also a good activity to set for homework as the students have to put in effort and often get their parents involved on their work.

12. Double jointed?
having unusually flexible joints especially of the limbs or fingers
Joint hypermobility
Some backgorund information taken from
Joint hypermobility: 
means some or all of your joints have an unusually large range of movement; you may be particularly supple at one or more joints.
occurs because connective tissue in the joints, muscles, tendons, and ligaments are more loose and stretchy than in most people. This means the joints are more flexible and can extend further. It is often first noticed when as a child you could bend into strange positions or were called ‘double jointed’.
can vary greatly between different people. If your hypermobility is mild it will not affect you too much and will not need treatment. If it is more severe you may be in some pain, your joints may often dislocate and you could injure yourself.
affects certain racial groups more than others and women more than men; this is because female hormones increase flexibility. In many cases, it is hereditary.
Causes
There are four factors that cause hypermobility:
1. The shape of the ends of the bones.
A joint is the junction between two bones. The shape of the bones defines the flexibility of the joint. Your range of movement will be larger if the socket that the bone moves around in (e.g. shoulder, hip) is narrow because it will allow more movement.
2. Weak or stretched ligaments (bands that hold your joints in place).
This is caused by problems with collagen (the substance found in tendons, ligaments and cartilage) and other proteins like elastin. All the joints in the body will be affected (except the spine), especially the knees and thumbs. This type of hypermobility in particular can be hereditary.
3. The tone of your muscles.
The tone of your muscles is controlled by your nervous system. You can increase your suppleness with activities such as yoga.
4. Your sense of joint movement.
If you have an abnormal sense of joint movement you may not be able to sense when a joint is over-stretched. This may also make you clumsy.
Hormones also affect hypermobility, as the female hormone oestrogen increases flexibility. Therefore symptoms may increase before a period and reduce after the menopause.
Exercise and some sports, eg running or squash can aggravate the joints. Low impact sports such as swimming and cycling are more advisable.
Diagnosis
Diagnosis for hypermobility is often based on the Beighton-modified version of the Carter and Wilkinson method. This consists of nine tests:
1. Can you put your hands flat on the floor with your knees straight?
2. Can you bend your left elbow backwards?
3. Can you bend your right elbow backwards?
4. Can you bend your left knee backwards?
5. Can you bend your right knee backwards?
6. Can you bend your left thumb back on to the front of your forearm?
7. Can you bend your right thumb back on to the front of your forearm?
8. Can you bend your little finger on your left hand up at 90° to the back of your hand?
9. Can you bend your little finger on your right hand up at 90° to the back of your hand?
If you answer yes to five or more out of nine, you are said to be hypermobile.

13. Summary There are 3 main types of joints: Fused joint e.g. skull
Ball and socket joint e.g. shoulder and hip
Hinge joint e.g. elbow and knee
Revise material covered in class.
Ask studenst to come up to the skeleton to identify joints.

14. Muscles and joints
OB26 understand the function of joints and muscles (including antagonistic pairs), tendons and ligaments, and the relationship between these and bones.
This lesson will include a more detailed look at joints - how they work with muscles to create movement, what joins muscle to bone and what joins bone to bone.
Introduction will be continued on the next slide.

15. What was holding this guys head in place?

16. What holds our bones together?
Ligaments connect bone to bone
Tough rope like fibres known as ligaments.
Restrict movement
Do our bones just stay in place of their own accord? What stops our skeleton from falling apart or our head falling off (reference to previous slide)? What stops the bones on the model skeleton from falling apart?
Learn this definition – ligaments connect bone to bone.
Whey do ligaments need to be tough? What actions do they allow/prevent? Think of your knee? Does anyone follow soccer/Gaelic/Hurling? Ever hear of your favourite player being out because of a torn ligament or even a damaged cruciate ligament? Try moving your knee in a direction you haven’t tried before? What happens? Why?
Torn Ligaments are injuries to a tough, ropelike fiber that connects a bone to another bone. Sudden force, a direct blow to a joint, a deep cut, or a smashing injury can cause Ligaments to Tear. Symptoms of a torn ligament may include, a pop or snap felt or heard at the time of the tear, pain and swelling, a wobbly, unstable joint, limited movement. – taken from
Ligaments restrict movement – prevent dislocation (

17. Can bones move on their own?2 1
To create the idea that a skeleton cannot work alone set up apparatus as per diagram.
Take 2 equal sized pieces of timber (about the length of your humerus and you radius).
Drill a hole where the green circles are located and push a screw and nut through each.
Ask the class to imagine that this is the arm of the skeleton. How will the skeleton raise the lower arm?
Next wrap string around the 3 screws as per diagram.
Ask the students to pull on 1 – this should raise the fore arm. Ask students to release 1 and pull on 2. This should lower the fore arm.
This will demonstrate that the bones in the skeleton cannot move on their own but need an external force.

18. What joins muscles to bones?
Tendons join muscle to bones
Strong and non-elastic
Pulls on bone
So we know that muscles are required for movement but how do muscle pull on our bones? How are they attached?
Tendons join muscle to bone –learn this definition.
With the palm of your hand facing towards you observe your wrist area. Now make a fist, bend it towards you and observe again.
Extra info.
- tendon is the end part of a muscle that attaches the muscle to the bone. 
The normally very elastic and soft muscle tapers off at the end to form the much more dense and stiff tendon. 
While this density makes the  tendons stronger, the lack of elasticity of the tendon and the constant pulling on its attachment to the bone with movement, makes it much more susceptible to a low level of tearing at a microscopic level.
  Tendinitis is usually seen after excessive repetitive movement with which the tendon gradually becomes tighter until the fibers start to tear.  For example, a person who plays tennis may over- use the muscles of the elbow through hitting the ball repetitively and cause tendonitis to the area.  

19. How do muscles work? Muscles can only actively contract
Relaxing does not require action
Muscles work in pairs
Called Antagonistic pairs
When one muscles contracts, the other relaxes
E.g. biceps and triceps
Muscles are required for movement of our body. They work with/against our bones so that we can create movement.
Ensour that the class understands that muscles only use energy to contract, thus they usually work in pairs - Muscles work in pairs known as antagonistic pairs – learn to spell.
Explain that the only action which can be carried out by a muscle is contraction i.e. when a muscle ceases to contract it automatically relaxes. This process does not require any energy. – get students to raise and lower their arms until they get tired. Ask is it both sides or just on that is getting tired?

20. The biceps and triceps - an antagonistic pair
Explain the antagonistic pair using first the diagram, then your own arm and then finally a volunteer form the class.
Again remind the students that muscles only contract actively.
Get the students to practise in pairs. As they are practising this movement walk around the class and ensure that they are correct.

21. Tendon Biceps Tendon Triceps Contracted Relaxed
Get the students to repeat the sentence whilst raising their forearms – when my biceps contracts my triceps relaxes and I raise my forearm.
Muscle man links back to slide 27 (how do muscles work?)

22. Tendon Biceps Triceps Tendon Relaxed Contracted
Get the students to repeat the sentence whilst lowering their forearms – when my triceps contracts my biceps relaxes and I lower my forearm.
Tendon

23. Tendon Biceps Tendon Triceps Contracted Relaxed
Get the students to repeat the sentence whilst raising their forearms – when my biceps contracts my triceps relaxes and I raise my forearm.

24. Tendon Biceps Triceps Tendon Relaxed Contracted
Get the students to repeat the sentence whilst lowering their forearms – when my triceps contracts my biceps relaxes and I lower my forearm.
Repeat this exercise until the students are confidents in what they say.
Muscle man links to the summary.
Tendon

25. Bone composition Bone is made of living and non-living material
The living material lays down the non-living
The information on this slide is not part of the junior cert. syllabus but is a common question in class. The following slide gives excess detail but will help answer a common question.
This diagram is more for demonstration purposes just so the students know that bone is living, bone marrow is found here, blood cells are made here.
“How does the blood get into the bone?” is a common question in class. The above diagram can be used to answer this question.
Is bone dead or alive? – all the people who have broken/fractured/chipped a bone – did it hurt?

26. What is bone made of? Organic – living cells and protein Cells
take up calcium salt from the blood
Cells release salts to make hard material
Protein
Flexibility
Inorganic –non-living
Calcium salts
Explain the information on the slide – bone is made of living material and non-living material. The living material – cells and protein provide flexibility and lay down the hard non-living material.

27. How do we keep our bones healthy?
Weight bearing exercise
Calcium
Vitamin D
This slide is very important as the students should try to implement these into their lifestyles. This can also be linked with the food pyramid and is good for revision.
Ask students good sources of calcium and vitamin D. What are weight bearing exercises?
X-ray is of a child with rickets as a result of vitamin D deficiency.
Here is some helpful extra information taken from:
Why is Exercise Important in Building and Maintaining Bone Mass? Bones can adjust their mass or density in response to stress - what this means is that when bones are subjected to exercise, they will bend slightly to absorb the impact. Normally, bones have movement of about 0.1% %; if the bones are subjected to a force that tries to bend the bones more than this, our body responds by adding extra new bone to that area. When less stress is sensed by our bodies, bone mass is removed.
In simple terms, the more we gently stress our bones, the more bone is deposited to keep the degree of bend within the 0.1% % parameters. Consequently, the more physically active we are, the more bone we will build, and a greater amount of essential nutrients such as Calcium, Magnesium and Vitamin D will be required. In general, active people need to build and replace more bone than people who do little exercise.
Why is Diet Important in Maintaining Healthy Bones?
The process of building, replacing and repairing bone is controlled by many different factors and, like all living tissues, bone is just as dependent on proper nutrition as other tissues in the body.
Our bodies need a wide range of different nutrients, vitamins and minerals to maintain healthy bones, the most important of which are Calcium, Magnesium, and Vitamin D. Trace minerals such as Boron and Manganese also play a role in calcium metabolism. Vitamin B6 is also used to provide tensile strength and structure of proteins in bone tissue.
Calcium is the key component of bone, and essential for bone health throughout our lives. Consumed calcium is ionised in our stomachs by the action of stomach acid, so that it is converted into a form that can be readily absorbed in the small intestine for use by our bodies. The amount of Calcium needed in our diets may vary according to our age, sex and lifestyle. Currently, the Recommended Daily Intake - the amount required to avoid deficiency - in the UK and Europe is 800 mg/day, although some expert groups suggest higher levels may be appropriate for optimum bone health, depending on age, lifestyle or other health factors

28. Summary Ligaments connect bone to bone Tendons join muscle to bones
Muscles can only actively contract
Muscles work in pairs called Antagonistic pairs
Bone is made of living and non-living material
Healthy bones need exercise, calcium and vitamin D.
Revise all the material covered in class today.
Pick a volunteer to demonstrate an antagonistic pair.
Make a particular effort to stress the importance of healthy bones, especially the role of exercise.
Hyperlink is to slide 29 (The first slide of antagonistic pairs)