Transportation in Animals and Plants
Overview
Blood circulates throughout the entire body — distributing oxygen and food, carrying away waste. Plants also have their own plumbing for water and food — xylem and phloem. Let us learn about this transport system.
Typed Notes
Blood — A vessel with 4 crew members
Blood is a connective tissue — cells floating in liquid plasma: (1) Plasma — the pale yellow liquid (90% water) — carrier of nutrients, waste, and hormones; (2) RBC (Red Blood Cells) — contain haemoglobin (iron-containing red pigment) — carry oxygen from the lungs to cells — this is why blood is red; (3) WBC (White Blood Cells) — the army: fights germs (their count increases during infection — forms pus); (4) Platelets — tiny fragments — collect at a wound and clot the blood — without them, bleeding from an injury would not stop. Blood group (A, B, AB, O) — must be checked carefully during transfusion.
Heart — A pump with 4 chambers
The heart is located in the chest, slightly to the left; its size is about the size of your own fist. 4 chambers: upper 2 are atria (blood comes in), lower 2 are ventricles (blood is pushed out). Valves — one-way doors — prevent backflow. Right side — impure blood (with CO2) → goes to lungs; left side — pure blood (with O2) → goes to the entire body. Heartbeat — one complete pumping cycle — 72-80 times per minute at rest (higher in children, increases with exercise); can be heard with a stethoscope (lub-dub — the sound of valves closing). Pulse — the same heartbeat felt at the wrist.
Arteries, Veins, Capillaries
(1) Arteries — carry blood away from the heart: high pressure — walls are thick and strong. (2) Veins — bring blood towards the heart: lower pressure — walls are thin; valves (one-way) — prevent backflow — this is why standing for long periods causes blood to pool in leg veins (varicose veins). (3) Capillaries — extremely thin (just one cell thick) — reach near every cell — this is where oxygen and nutrients are delivered and waste is collected. The network of all three — covers the entire body — more than 1,00,000 km in total!
Plants' Plumbing — Xylem and Phloem
Plants have two pipe systems: (1) Xylem — carries water and minerals from roots upward to leaves (one direction only). How does it go upward? Leaves release water as vapour (transpiration) — this pulls water upward from below — called transpiration pull (just like drinking juice through a straw). (2) Phloem — carries food made in leaves to all parts of the plant (roots, fruits, new leaves) — can move in both directions. Both are found together in the stem as bundles (vascular bundles) — this is how the plant's food and water supply system works. Plants also produce waste: resins, gums — stored in old leaves — when leaves fall, waste is removed.
Key Concepts
Revision ke liye ek nazar — exam se pehle yahi padhna hai.
- 01Blood: Plasma (liquid — 55%, carrier of nutrients and waste), RBC (haemoglobin — carries oxygen), WBC (fights germs — immunity), Platelets (clots blood — on wounds).
- 02Heart: 4 chambers (2 atria on top, 2 ventricles below) — acts as a pump. Heartbeat ~72-80/min (heard with a stethoscope).
- 03Vessels: Arteries — carry blood away from the heart (thick walls, high pressure); Veins — carry blood towards the heart (thin walls, valves — prevent backflow); Capillaries — very thin — exchange happens at every cell.
- 04Excretion: Kidneys — filter blood — remove urea to form urine (stored in bladder); sweat also removes waste.
- 05In Plants: Xylem — carries water and minerals from roots to leaves (upward); Phloem — carries food from leaves to all parts (both directions). Transpiration pulls water upward.
Questions & Solutions
Pehle khud try karo — phir solution kholo. Yahi tariqa topper banata hai.
Write the 4 components of blood and their functions.
How many chambers does the heart have and why so many?
What is the difference between arteries and veins?
What does the kidney do?
How does water travel upward in plants when there is no pump?
What is the difference between xylem and phloem?
Blood: plasma (carrier), RBC (O2 — haemoglobin), WBC (fights germs), platelets (clot). Heart has 4 chambers, beats 72-80/min, valves ensure one-way flow. Arteries carry blood out (thick walls), veins bring blood in (valves), capillaries handle exchange. Kidneys — remove urea → urine. Plants: xylem (water upward — transpiration pull), phloem (food in both directions).
Chapter-end quiz
4 MCQsOption tap karo — turant pata chalega sahi ya galat, explanation ke saath.
Q1.Which blood cell carries oxygen?
Q2.How many chambers does the heart have?
Q3.Which structure distributes food in plants?
Q4.What do we feel as pulse at the wrist?
Mark karo — dashboard par progress dikhega.