--- marp: true theme: default html: true --- # Organ systems Year 8 Biology · From cells to organs --- ## Today **We are learning to** an organ system is a group of organs that work together to do a job the whole organism needs. In an animal, the circulatory system (heart, blood vessels, blood) delivers oxygen and nutrients; in a plant, the vascular system (xylem and phloem in roots, stems and leaves) carries water and sugars. If one organ fails, the system fails. - I can name organs of an animal and a plant system and say what each does. - I can say how the organs work as a system. - I can compare the two systems. --- ## Why it matters > Your heart can't keep you alive on its own, and neither can your lungs. Why do organs only make sense as a team? --- 💬 Discussion ## Engage: predict **In the circulatory system, the heart pumps blood through blood vessels to all parts of the body. If the blood vessels to one leg are blocked, what is most likely?** - Only the heart is affected - That leg doesn't get enough oxygen and nutrients, so the system as a whole can no longer do its job there - Nothing: the heart still works - The other leg gets more blood so the body is fine --- ✅ Check ## What happened? * The leg is starved of oxygen and nutrients. A system only works when every organ in it does its part: pump, vessels and blood together. --- ✅ Check ## Circulatory system **Match each part of the circulatory system to its job.** | | | |---|---| | `Heart` | A. Carry blood back to the heart | | `Arteries` | B. Pumps blood around the body | | `Veins` | C. Carries oxygen, nutrients and waste | | `Capillaries` | D. Carry blood away from the heart at high pressure | | `Blood` | E. Thin walls let oxygen and nutrients pass into cells | * Answer: Heart → B. Pumps blood around the body; Arteries → D. Carry blood away from the heart at high pressure; Veins → A. Carry blood back to the heart; Capillaries → E. Thin walls let oxygen and nutrients pass into cells; Blood → C. Carries oxygen, nutrients and waste --- ✅ Check ## Plant system **Match each part of a plant's vascular system to its job.** | | | |---|---| | `Roots` | A. Take in water and minerals from the soil | | `Xylem` | B. Carries sugars from the leaves to where they are needed | | `Phloem` | C. Make sugars by photosynthesis and lose water vapour | | `Leaves` | D. Carries water and minerals up the plant | * Answer: Roots → A. Take in water and minerals from the soil; Xylem → D. Carries water and minerals up the plant; Phloem → B. Carries sugars from the leaves to where they are needed; Leaves → C. Make sugars by photosynthesis and lose water vapour --- ✅ Check ## The shared problem **What survival problem do the circulatory system and a plant's vascular system both solve?** - Making sound - Moving materials (nutrients, water, gases) to every cell that needs them - Getting rid of heat * Answer: Moving materials (nutrients, water, gases) to every cell that needs them --- ✅ Check ## The difference **How is the plant's system different from the animal's?** - A plant's system moves only water; an animal's moves food as well - A plant has a heart in its roots - A plant has no pump: water is pulled up by evaporation from the leaves, and the tubes are fixed in place * Answer: A plant has no pump: water is pulled up by evaporation from the leaves, and the tubes are fixed in place --- ✅ Check ## Elaborate: the digestive system **In digestion, food goes mouth, then stomach, then small intestine. If the small intestine fails to absorb nutrients, what is the effect on the system?** - The mouth does the absorbing instead - No effect because the stomach still works - The system fails at its job: food is broken down but the nutrients never get into the blood * Answer: The system fails at its job: food is broken down but the nutrients never get into the blood --- ✅ Check ## Elaborate: a machine for an organ **A dialysis machine cleans the blood of someone whose kidneys no longer work. What does it do that the kidney does?** - Filters waste out of the blood, while keeping useful things in - Pumps the blood round the body - Makes new blood cells * Answer: Filters waste out of the blood, while keeping useful things in --- ## Evaluate: look back Write one sentence: "At first I thought… Now I think… because…" **Revision summary** - An **organ system** is a group of organs working together to do a job the whole organism needs. - Animal example: **circulatory** (heart, vessels, blood). Plant example: **vascular** (roots, xylem, phloem, leaves). - If any organ in a system fails, the system can't do its job. - Both systems solve the same problem: **moving materials to every cell**. --- ✅ Check ## Exit ticket **Say in a sentence how a plant's vascular system and an animal's circulatory system are alike, and one way they differ.** * Alike: both move materials to every cell. Different: the animal pumps blood with a heart, while the plant has no pump and water is pulled up the xylem as it evaporates from the leaves.