BBC Bitesize - GCSE Physical Education - Skeletal system - Edexcel - Revision 3
Oct 11, Joints are the place where two bones meet or connect. tough fibrous connective tissue that function to connect one bone to another, forming the joint. Learn more about creating dynamic, engaging presentations with Prezi. skeletal system test Learn with flashcards, games, and more — for free. The places in the skeleton where two more bones meet are called ____, and these. Apr 23, Our skeleton forms a strong, solid internal framework of bones for our the surfaces of two or more bones meet and articulate with each other.Elbow Joint: Bones, Muscles & Movement - Human Anatomy - Kenhub
They allow flexion and extension of a joint. At the ankle, different terms are used. When the toes are pointed downwards, it is plantar flexion and when the toes are pointed upwards it is dorsiflexion. Ball and socket - these types of joint can be found at the shoulder and hip and allow movement in almost every direction.
A ball and socket joint is made up of a round end of one bone that fits into a small cup-like area of another bone. Pivot - this joint can be found in the neck between the top two vertebrae. It allows only rotational movement such as moving your head from side to side as if you were saying 'no'. Condyloid - this type of joint is found at the wrist.
It allows you to flex and extend the joint, and move it from side to side. The joints of the skull are called sutures.
Slightly movable — two or more bones are held together so tightly that only limited movement is permitted — for example, the vertebrae of the spine. Freely movable — most joints within the human body are this type. Motion is the purpose of the joint.
Freely moving joints The six types of freely movable joint include: Ball and socket joint — the rounded head of one bone sits within the cup of another, such as the hip joint or shoulder joint. Movement in all directions is allowed. Saddle joint — this permits movement back and forth and from side to side, but does not allow rotation, such as the joint at the base of the thumb.
Hinge joint — the two bones open and close in one direction only along one plane like a door, such as the knee and elbow joints. Condyloid joint — this permits movement without rotation, such as in the jaw or finger joints.
Pivot joint — one bone swivels around the ring formed by another bone, such as the joint between the first and second vertebrae in the neck.
Gliding joint — or plane joint. Smooth surfaces slip over one another, allowing limited movement, such as the wrist joints. They also help the body perform other functions so we can grow and remain strong, such as chewing food and then moving it through the digestive system. The human body has more than muscles. They are connected to bones by tough, cord-like tissues called tendons, which allow the muscles to pull on bones.
If you wiggle your fingers, you can see the tendons on the back of your hand move as they do their work. Humans have three different kinds of muscle: Skeletal muscle is attached to bone, mostly in the legs, arms, abdomen, chest, neck, and face. Skeletal muscles are called striated pronounced: STRY-ay-ted because they are made up of fibers that have horizontal stripes when viewed under a microscope.
These muscles hold the skeleton together, give the body shape, and help it with everyday movements they are known as voluntary muscles because you can control their movement.
- Skeletal System: Bones, Joints, Cartilage, Ligaments, Bursae
- Bones, Muscles, and Joints
They can contract shorten or tighten quickly and powerfully, but they tire easily and have to rest between workouts. Smooth, or involuntary, muscle is also made of fibers, but this type of muscle looks smooth, not striated.
Generally, we can't consciously control our smooth muscles; rather, they're controlled by the nervous system automatically which is why they are also called involuntary. Examples of smooth muscles are the walls of the stomach and intestines, which help break up food and move it through the digestive system.
Smooth muscle is also found in the walls of blood vessels, where it squeezes the stream of blood flowing through the vessels to help maintain blood pressure. Smooth muscles take longer to contract than skeletal muscles do, but they can stay contracted for a long time because they don't tire easily. KAR-dee-ak muscle is found in the heart. The walls of the heart's chambers are composed almost entirely of muscle fibers.
Cardiac muscle is also an involuntary type of muscle. Its rhythmic, powerful contractions force blood out of the heart as it beats. Muscles and Movement Even when you sit perfectly still, there are muscles throughout your body that are constantly moving.
Muscles enable your heart to beat, your chest to rise and fall as you breathe, and your blood vessels to help regulate the pressure and flow of blood through your body. When we smile and talk, muscles are helping us communicate, and when we exercise, they help us stay physically fit and healthy. The movements your muscles make are coordinated and controlled by the brain and nervous system. The involuntary muscles are controlled by structures deep within the brain and the upper part of the spinal cord called the brain stem.
The voluntary muscles are regulated by the parts of the brain known as the cerebral motor cortex and the cerebellum. When you decide to move, the motor cortex sends an electrical signal through the spinal cord and peripheral nerves to the muscles, causing them to contract.
The motor cortex on the right side of the brain controls the muscles on the left side of the body and vice versa. Sensors in the muscles and joints send messages back through peripheral nerves to tell the cerebellum and other parts of the brain where and how the arm or leg is moving and what position it's in.
This feedback results in smooth, coordinated motion. If you want to lift your arm, your brain sends a message to the muscles in your arm and you move it.
When you run, the messages to the brain are more involved, because many muscles have to work in rhythm. Muscles move body parts by contracting and then relaxing. Your muscles can pull bones, but they can't push them back to their original position. So they work in pairs of flexors and extensors.
The flexor contracts to bend a limb at a joint.
Skeletal System | Skeleton Bones, Joints, Cartilage, Ligaments, Bursae
Then, when you've completed the movement, the flexor relaxes and the extensor contracts to extend or straighten the limb at the same joint: For example, the biceps muscle, in the front of the upper arm, is a flexor, and the triceps, at the back of the upper arm, is an extensor.
When you bend at your elbow, the biceps contracts. Then the biceps relaxes and the triceps contracts to straighten the elbow. Joints allow our bodies to move in many ways.
Some joints open and close like a hinge such as knees and elbowswhereas others allow for more complicated movement — a shoulder or hip joint, for example, allows for backward, forward, sideways, and rotating movement. Joints are classified by their range of movement. Immovable, or fibrous, joints don't move. The dome of the skull, for example, is made of bony plates, which must be immovable to protect the brain.
Between the edges of these plates are links, or joints, of fibrous tissue.