Structure and function of body systems

What is a tissue? A tissue is a group of similar cells that work together to perform a certain function. E.g. of Animal Tissue - Muscle Tissue E.g. of Plant Tissue - Xylem Tissue What is an organ? An organ is a group of different tissues working together to perform a certain function. E.g. of an Animal Organ - Heart, lungs, stomach (etc.) E.g. of a Leaf Organ - Root, leaf (etc.) What is an Organ System? An organ system is a group of organs working together to perform a certain function.    E.g. of an Organ System - Respiratory System,  takes in oxygen and removes carbon dioxide What is an Organism An organism is a different group of organ systems working together to perform a certain function. The Hierarchy         Cell - Tissue - Organ - Organ System - Organism

Gas Exchange Gas exchange is where you breathe in oxygen and breathe out carbon dioxide. This takes place in your lungs.  They are made out of elastic tissue which can expand when you breathe in and out. This then helps you to take in more oxygen. The lungs are then protected by your rib cage this is because our lungs are delicate. There are a lot of alveoli in our lungs which creates a large surface area; they have cell wall which are very thick. When we breath in we inhale air and when we breathe out we exhale air. The air we breathe in contains water vapour and that is why you sometimes see breath on the mirror.

Breathing   Breathing is when you take in air let it out, as we have talked about it in Gas Exchange. When our bodies breathe our muscles inside our chest contract (tighten). When we inhale: The muscles between our rib contracts (pulls the rib cage up and out) The diaphragm contracts - it moves down The volume inside your chest increases The pressure inside your chest decreases and when we exhale: The muscles between our rib relaxes (moves down and in) The diaphragm relaxes - it moves up The volume inside your chest decreases The pressure inside your chest increases

Skeleton   A bone is a living tissue with a blood supply. Calcium makes your bones strong and slightly flexible. Excercise and a balanced diet are important to keep bones healthy. The skeleton consists of all your bones in your body. On average the adult human body have 206 bones. Why do we have a skeleton? - Supports vital organs - Helps the body move - Makes blood cells - Supports the body   Support - Holds your internal organs in place and the Vertebral column holds the body upright. Movement -  Muscles are attached to bones. If the muscles pulls on a bone, it will cause to move. The skeleton moves at joints, such as our knee. The movement about our joins allows us to move. Protect - Bones are hard and strong to protect vital organs. (E.g.) Skull protects brain Ribcage protects heart and lungs Backbone protects spinal cord Making Blood Cells -  Some longs bones inside your body are not solid and have a soft tissue called a Bone Marrow. Bone Marrow make red and white blood cells. Red blood cells are used to carry oxygen. White blood cells are used to fight infection.  

Movement Joints Joints are where there are two or more bones joined together; most are flexible but some cannot move. There are three types of joints: Hinge joints - For movement back and forward E.g. Knee & Elbow Ball & Socket joints - For movement in all directions E.g. Hips & Shoulders Fixed Joint - Do not allow any movement E.g. Skull    Muscles Muscles are found all over the body. They are a type of tissue as they are made up of lots of muscles cells that work to cause movement.  How can you measure muscle strength? The force of a muscle can be measured by how much force it exerts.  You can measure the force of a muscle using a Newton Scale. The unit of force is Newtons. Types of Muscles  Shoulder Muscles  Abdominal Muscles Triceps Biceps Neck Muscles Calf Muscles Thigh Muscles Shin Muscles How do Muscles work? Muscles contract (get shorter) Muscles are attached to bones by tendons. If they contract and they are attached to a bone the bone will move. How do pairs of muscles work together? At each joint a pair of muscles works together to cause movement. These are known as antagonistic muscles For example, the biceps and triceps are a pair of antagonistic muscles. They are used to bend and straighten your arm at the elbow joint. The biceps contract and the triceps relax.