Transportation in Animals
The basic needs of animals are food, water and oxygen to survive.
These basic needs must be supplied to each body part of animals to get energy and this is done by the circulatory system.
And waste generated in the animal’s body should be removed by transporting it to the excretory system.
Circulatory System
The circulatory system consists of blood, blood vessels and the heart.
It involves the circulation of oxygen, minerals and nutrients to all the body parts by the blood.
Blood:
Blood is a red fluid and it is red because of the presence of haemoglobin.
Haemoglobin is responsible for the transport of oxygen in all parts of the body.
In blood, there are three types of cells
Red Blood Cells (RBC): It transport oxygen from the lungs to different parts of the body and carbon dioxide from different parts of the body to the lungs
White Blood Cells (WBC): Provide immunity to fight with foreign microorganisms which can cause disease and infection.
Platelets: They form a shield-like structure at the place of injury to stop bleeding; this is generally referred to as clotting of blood.
Plasma: The blood contains cells and fluid, the fluid part is known as plasma.
Blood Vessels:
The pipe-like structure through which blood flow is known as blood vessels.
There are Three Types of Blood Vessels:
Arteries: They carry oxygenated blood away from the heart to the body’s tissue.
Veins: They carry deoxygenated blood away from the body’s tissue to the heart.
Capillaries: This acts as a binding agent which binds arteries and veins.
Heart:
It is a muscular organ present in the left side of the chest and it is of fist size.
It is the most important organ in our body because it helps in the transportation of oxygen and other nutrients through the blood.
The heart is divided into four chambers so that oxygenated and deoxygenated blood does not mix.
The upper two chambers of the heart are called atria and they are the left atrium and right atrium
The lower two chambers of the heart are called ventricles and they are the left ventricle right ventricle
Heartbeat is the contraction and relaxation of the muscles of which the walls of chambers of the heart are made up.
Excretion in Animals
The removal of unwanted or waste material from the body is known as excretion.
See AlsoNCERT Solutions for Class 7 Science Chapter 11 Transportation in Animals and PlantsNCERT Solutions Class 7 Science Chapter 11 Transportation in Animals and PlantsTransportation In Plants - Means Of Transportation In PlantsTransportations in Animals and Plants Important Questions Class 7 Science Chapter 11Carbon dioxide is excreted from the animal body by the process of exhalation.
Undigested food is excreted from the animal body by the process of egestion.
Excretory System in Human
The system which is responsible for the removal of waste material from the body is known as the excretory system.
It consists of the kidney, ureter, urinary and urethra.
Kidney: It is of bean-shaped structure and its main purpose is to filter the blood and remove waste material in the form of urine.
Urinary Bladder: It stores urine so that urination is not continuous.
Ureter: It is of pipe-like structure which joins the kidney and urinary bladder and provides passage for urine to flow from the kidney to the urinary bladder.
Urethra: It is a urinary opening that allows the urine to pass away from our body.
Transportation in Plant
The basic needs of plants are water, nutrients and carbon dioxide to survive.
The leaves prepare food by the process of photosynthesis which involves combining water and carbon dioxide.
Transport of Water and Minerals
Plants absorb water and minerals by roots from the soil.
The transportation of water, minerals and food in plants is accomplished by vascular tissues.
Vascular tissues are pipe-like structures in plants that allow transportation of water, minerals and food. It is connected from leaves to roots.
Vascular Tissues are of Two Types:
Xylem: Helps in the transportation of water and minerals from the roots to all the parts of plants.
Phloem: Helps in the transportation of food prepared by leaves to all the parts of plants.
The water absorbed by roots is to be transported to leaves i.e., the top part of the plant therefore the upward movement of water is due to the phenomenon called transpiration.
Transpiration is the process of losing water from the leaves in the form of water vapour.
On losing water leaves create a suction pull so that the water can be pulled from roots to leaves again.
Transportation in Animals and Plants Class 7 Science Notes
Transportation in Humans
Circulatory System
The system that transports blood from the heart to different parts in our body and brings it back to the heart is called the circulatory system. The human circulatory system consists of:
Heart: A highly muscular structure located in the chest cavity.
Blood Vessels: Arteries, veins and capillaries.
Blood: A fluid connective tissue that circulates through this system.
Let us explore each component in more detail.
Heart
Heart is the most important and sensitive element of our body. It beats continuously to act as a pump for the transport of blood. The heart is placed in the chest cavity slightly tilted towards the left. It is roughly the size of a human fist. The human heart has four chambers; the upper two chambers are called atria while the lower ones are called ventricles. The partition between the chambers helps to avoid mixing up the oxygen-rich blood with the carbon dioxide-rich blood.
The left side of the heart receives blood rich in oxygen from lungs and sends it to each part of the body while the right side receives blood rich in carbon dioxide from all parts of the body and sends it to the lungs for purification.
Heartbeat: A heartbeat is a rhythmic contraction followed by relaxation of the muscles of the heart.
Pulse: Pulse is the throbbing of an artery due to the pressure of blood flow.
Stethoscope: It is a device to amplify the sound of the heart.
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Blood
It is a fluid connective tissue. The fluid part is called plasma. Plasma consists of different suspended cells. The heart circulates blood throughout the body.
Red Blood Cells (RBCs): It contains a red pigment called haemoglobin that imparts the characteristic red colour to blood. This pigment binds with oxygen and transports it to all the cells of the blood.
White Blood Cells (WBCs): It protects us by fighting against disease-causing germs.
Platelets: It helps in blood clotting at the site of injury.
Functions of Blood
The main function of blood is to transport oxygen from the lungs to all the parts of the body and carbon dioxide to the lungs for purification.
It transports digested food to all parts of the body.
Blood maintains a constant body temperature.
It also transports waste to the kidneys for excretion.
Blood Vessels
The three types of blood vessels are arteries, veins and capillaries. The arteries and veins act in contrast to one another while the capillaries form the connecting link.
Arteries | Veins |
Carry blood away from the heart. | Carry blood towards the heart. |
Carry blood rich in oxygen except for the pulmonary artery. | Carry blood rich in carbon dioxide except for the pulmonary vein. |
Arteries are deep-seated in the skin. | Veins are superficial, close to the surface of the skin. |
Arteries are narrow with thick wall. | Veins are wider with thin wall. |
Capillaries
Capillaries are extremely thin vessels that connect arteries with veins. Oxygen and digested food, carbon dioxide and other wastes are exchanged between the blood and the surrounding cells through walls of capillaries.
Excretion in Animals and Humans
The process of elimination of metabolic waste products from the body is called excretion.
Excretion in Animals
In organisms like Amoeba, Hydra, sponges, etc. there are no special excretory organs. The waste products are excreted through diffusion by general body surface.
In aquatic animals like fish, cellular waste like ammonia directly dissolves in water.
Birds, reptiles and insects excrete nitrogenous wastes in the form of uric acid.
Other land-living mammals excrete urea as the major nitrogenous waste.
Human Excretory System
Kidney
There are two kidneys in the human excretory system, one each on the right and left side just below the stomach. Kidneys are also called magic filters because they filter only unwanted substances from the blood.
The urine passes from the kidneys into the urinary bladder through the tube-like uterus. Urine is stored in the urinary bladder and is passed out through the urinary opening called the urethra.
An adult human passes approximately 1- 1.8 litres of urine in a day.
In case, the kidneys stop functioning properly then the wastes start to accumulate in the blood. This is very dangerous for humans. In order to filter the blood periodically, a technique is used, which is called dialysis.
Sweat
Sweat is the moisture discharged through the pores present in the skin. It is produced by sweat glands in the skin. Sweat removes water and salts from the body.
Transportation in Plants
The vascular system in plants helps to carry water, minerals, food or wastes from one part of the plant to another to perform various functions. It is made up of two types of tubes called Xylem and Phloem.
A tissue is a group of cells that performs a special function in an organism. The vascular tissue for transport of water and minerals in plants is xylem while the transport of organic products of photosynthesis is carried out by phloem.
Both xylem and phloem are arranged in a compact structure, called vascular bundles.
Xylem
Xylem forms a network of channels that helps to conduct water and dissolved minerals upward i.e. absorbed by the roots to the leaves through the stem. They are generally made up of dead cells.
Phloem
Phloem contains vessels called sieve tubes that translocate food downward i.e. from manufactured by the leaves to all parts of the plant. They are generally made up of living cells.
Transportation Water and Minerals
Roots of plants have tiny outgrowths called root hair through which water and dissolved mineral salts enter. The root hair increases the surface area for absorption of water and mineral salts. The roots absorb water from the soil by a process called osmosis.
Osmosis is a process of passage of water over short distances from an area where it is more to an area where it is low across a cell membrane.
The root cells continuously absorb water and mineral salts from the soil. Some of the excess water absorbed by roots is lost as water vapour through stomata in the leaves by transpiration. This generates a suction pull, which takes water to great heights in tall trees. Transpiration also cools the plant.
Important Points to Remember
In living organisms, food, oxygen and waste products etc. have to be transported from one part of the body to the other.
Plants have a transport system consisting of xylem (water and minerals) and phloem (food).
In humans, the transport of materials takes place through the blood.
Blood is pumped by the heart and circulated to all the parts of the body through the blood vessels.
Blood consists of liquid plasma and the three types of blood cells, red blood cells, white blood cells and platelets floating in it.
There are three types of blood vessels that transport blood – arteries, veins and capillaries.
The human heart has four chambers – The upper two are called the atria or auricles and the lower two are called ventricles.
Contraction of muscles of the heart makes a heartbeat. This is felt as a throbbing in the artery near the wrist and is known as pulse.
Excretion refers to the removal of metabolic wastes from the body.
Excretion in humans occurs through lungs, skin and kidneys.
Kidneys filter waste from the blood, which is excreted from the body in the form of urine.
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