Organs An organ is a combination of tissues that are coordinated to perform a range of functions. In animals for example the stomach is made up of tissues such as: - Muscle to and mix stomach contents. - Epithelium to protect the wall and produce secretions. - Connective tissue other tissues. In plants a leaf is made up of the following tissues: - Palisade mesophyll made of leaf palisade cells that photosynthesize. - Spongy mesophyll for gaseous diffusion. - Epidermis to protect the leaf and allow gaseous diffusion. - Phloem to transport organic materials away from the leaf. - to transport water and ions into the leaf. Organ systems - The digestive system: Digests and processes food, is made up of organs including the salivary glands, oesophagus, stomach etc. - The respiratory system: Used for breathing and gas exchange. It’s made up of organs that include the trachea, bronchi and lungs. - The circulatory system: Pumps and circulates blood. It is made up of organs that include the heart, arteries and veins. Exchange and transport Examples of things need to be interchanged between an organism and its environment include: Respiratory Nutrients Excretory products Heat This exchange can take place in two ways: Passively by diffusion and osmosis Actively by active transport Surface area to volume ratio For exchange to be effective, the surface area of the organism must be large compared to the volume.
Organs An organ is a combination of tissues that are coordinated to perform a range of functions. In animals for example the stomach is made up of tissues such as: - Muscle to and mix stomach contents. - Epithelium to protect the wall and produce secretions. - Connective tissue other tissues. In plants a leaf is made up of the following tissues: - Palisade mesophyll made of leaf palisade cells that photosynthesize. - Spongy mesophyll for gaseous diffusion. - Epidermis to protect the leaf and allow gaseous diffusion. - Phloem to transport organic materials away from the leaf. - to transport water and ions into the leaf. Organ systems - The digestive system: Digests and processes food, is made up of organs including the salivary glands, oesophagus, stomach etc. - The respiratory system: Used for breathing and gas exchange. It’s made up of organs that include the trachea, bronchi and lungs. - The circulatory system: Pumps and circulates blood. It is made up of organs that include the heart, arteries and veins. Exchange and transport Examples of things need to be interchanged between an organism and its environment include: Respiratory Nutrients Excretory products Heat This exchange can take place in two ways: Passively by diffusion and osmosis Actively by active transport Surface area to volume ratio For exchange to be effective, the surface area of the organism must be large compared to the volume.
unit_2_revision_notes.docx