Transportation in Animals & Plants Summary Class 7 NCERT Summary

Circulatory System

• All multicellular organisms have a specialized system to transport nutrients and other necessary materials to the cell and the wastes away from the cell. This system is known as circulatory system.
• Circulatory system is the transportation system of human body. It has three major parts:
  (i) Blood
  (ii) Blood vessel
  (iii) Heart

Blood

• It is a fluid connective tissue that is pumped throughout the body by heart.

Functions of Blood

• It transports oxygen and nutrients to various parts of the body.
• It also transports wastes for removal from the body.

Composition of Blood

• It contains plasma, red blood cells, white blood cells, and platelets.
• Plasma is the fluid part of blood.
• Red blood cell contains a pigment called haemoglobin. It carries oxygen and transports it to all parts of the body.
• White blood cell protects body against infections. These are also known as leucocytes.
• Platelets help in clotting of blood.

Lymph

• Lymph is a watery clear fluid. It is blood minus RBC.
• This fluid distributes immune cells and other factors throughout the body.
• It also interacts with the blood circulatory system to drain fluid from cells and tissues.
• The lymphatic system contains immune cells called lymphocytes, which protect the body against foreign antigens (viruses, bacteria, etc.) that invade the body.

Heart

• It is the main pumping organ of our body that beats continuously.
• It pumps oxygen-rich blood to all parts of the body and carbon dioxide-rich blood to the lungs. .
• Human heart is four chambered as shown in the figure below, and located in the chest cavity.
• The upper two chambers are called atria while lower two chambers are called ventricles.
• A muscular wall between the chambers prevents the mixing up of blood rich in oxygen and blood rich in carbon dioxide.
• The rhythmic contraction and expansion of heart is the heart beat.
• Doctors use stethoscope for listening to the heart sounds.
• The human heart beats about 70 to 80 times per minute in an adult.

There are three types of blood vessels:

(i) Arteries

(ii) Veins

(iii) Capillaries

• Arteries carry oxygen-rich blood from the heart to various organs of the body.
• Pulmonary artery is the only artery that carries CO2-rich blood from heart to lungs.
• The walls of arteries are thick and elastic in order to tolerate high pressure of the blood.
• Pulse is the rhythmic contraction and expansion of arteries with each beat of heart.
• The number of beats per minute is the pulse rate.
• A resting person usually has a pulse rate between 72 to 80 beats per minute.

Veins

• Veins carry CO₂-rich blood from various organs towards the heart.
• They are thin-walled, non-elastic vessels that do not possess valves.
• Pulmonary veins carry oxygen-rich blood from lungs to heart.

Capillaries

Capillaries are thin-walled blood vessels. They connect arteries with veins.

Excretory system

• The organ system that performs the function of excretion is known as the excretory system.

Excretion

• It is the process of removing harmful waste products produced in the cells of living organisms.
• The excretory system in humans includes – a pair of kidneys, a pair of ureters, a urinary bladder and a urethra.

Kidney

• It is the main excretory organ of the human body.
• It plays an important role in the formation of urine. Human kidney produces about 1 – 1.8L of urine in a day.
• The urine consists of 95% water, 2.5% urea and 2.5% other waste products.
• Nephrons are the basic filtering units of the kidneys.
• The main components of a nephron are the glomerulus, Bowman’s capsule, and a long renal tube.
• Ureter carries urine to the bladder.
• Urinary bladder collects and stores urine.
• Urethra carries urine out of the body.
• Dialysis- The process of removing wastes using an artificial kidney is called dialysis.

Transport in plants

• Plants have specialized vascular tissues called xylem and phloem for the transport of water, minerals and food respectively to all parts.

Transport of Water in Plants

• Plant roots have hair that increase the surface area for absorption of water and minerals.
• Root hair are deficient in water as they continuously supply the absorbed water to the stems and leaves.
• This creates a concentration gradient, which allows the active uptake of water by the root xylem thereby creating a column of water, which steadily pushes upwards.

Transportation of food in Plants

• Leaves prepare food for plant by the process called photosynthesis.
• The prepared food is transported to remaining parts of the plants by a specialized vascular tissue known as phloem.
• The phloem forms a network of channels that transports food to the stem and to the roots of the plant.

Excretion in plants

• Plants get rid of the excess of water by transpiration.
• In transpiration water evaporates into the atmosphere through stomata.
• Stomata are the tiny openings or pores on the surface of leaves which help in the gaseous exchange and transpiration.