Plant tissues. In this video we will learn about plant tissues. Plant tissues are mainly divided into two groups.
The first one is meristematic tissue and the second one is permanent tissue. First let us learn about meristematic tissue. In our body Growth is uniform.
That means all parts of our body grow uniformly. But in plants, growth is observed only in certain regions. The reason for this is, the tissues that are responsible for the growth in plants are located only in certain parts of the plant. This special tissue is called meristematic tissue. Do you know the locations of meristematic tissues in plants?
The meristematic tissue of plants is classified into three types depending upon its location. They are 1. Epical meristem, 2. Lateral meristem and 3. Intercalary meristem. Epical meristem. This meristematic tissue is present at the tips of stem and root.
This epical meristem helps the stem and roots to increase their growth in lengthwise. Second one, Lateral meristem. This meristematic tissue is found in the corcambium and vascular cambium of plants. This lateral meristem helps the plants to increase their girth. Now, the third one, Intercalary meristem.
This meristem is mostly found in the monocot plants like grass. Intercalary meristems are found at the base of the leaf and at the node. Now let us see the characteristics of meristematic tissue.
The cells of the meristematic tissues are very active. The cytoplasm of meristematic tissue is very dense. It has a big prominent nucleus and the cell wall is thin.
Generally, plant cells possess big vacuoles. But if you observe the meristematic cells, they do not have any vacuoles. Do you know the reason? Why the meristematic cells do not have a vacuole? If you know the answer, please write it in the comment section.
Now, let us learn about permanent tissues in plants. Do you know how the permanent tissues in plants are formed? We learnt about meristematic tissues.
Meristematic tissue is the dividing tissue. That means, the cells of meristematic tissue divide continuously. If these cells stop dividing, then they take up a specific shape and a specific job and forms the permanent tissue.
So, permanent tissues are formed by the differentiation of meristematic tissue. Do you know what is differentiation? The process in which unspecialized cells becomes specialized cells.
We can compare the unspecialized cells as the students of a medical college or university. After they graduate, they may take up a specialization and becomes a specialist. In the same way, the young, immature, unspecialized cells like myristematic cells get differentiated into permanent tissue with specific functions. So, the process of young, immature, unspecialized cells taking up a permanent shape, size and a specific function is called differentiation.
Now let's see the simple permanent tissue. Simple permanent tissue is of three types. 1. Parenchyma 2. Cholenchyma 3. Sclerenchyma First, let us learn about parenchyma. Characteristics of parenchyma tissue The cells of parenchyma tissue are thin-walled.
They are living cells. They are loosely packed and thus There are large spaces between the cells of this tissue. Do you know the functions of parenchyma? The cells of parenchyma tissue present in the leaf consist of chloroplasts and performs photosynthesis. In such cases, this kind of parenchyma is called chlorenchyma.
Number 2. Parenchyma stores food. The pulp of the fruits is nothing but parenchyma tissue. Hence, it stores food.
Number 3. Parenchyma makes the plants float. In aquatic plants, large air cavities are present in parenchyma, which helps the plant to float on water. This parenchyma is called Next we see another type of simple permanent tissue called colonchyma. Characteristics of colonchyma.
The cells of colonchyma are living cells. They are elongated cells with irregular thickenings at the corners. The intracellular space between the cells of colonchyma is very less. Now let's see the functions of colonchyma.
like tendrils and stems of climbers without breaking. It also provides mechanical support. Next, we see the third type of simple permanent tissue, sclerenchyma. Characteristics of sclerenchyma.
The cells of sclerenchyma are long, narrow and dead. The cell walls are thickened due to the presence of a compound called lignin. Due to thick cell walls, there is very less space are no space inside the cells. This tissue is located around the vascular bundles, in the stems, and in the veins of leaves. It is also located in covering of seeds and nuts.
The covering on the coconut, that is the coconut husk, is made up of sclerenchyma tissue. Let's see the functions of sclerenchyma. It provides mechanical strength to the plants.
This tissue makes the plant and its parts hard and stiff. This is about the simple permanent tissue in plants. Now, let us learn about epidermis. Just like how our bodies are protected by skin, the plant bodies are protected by a layer of cells called epidermis. So, epidermis is the outer protective covering of a plant.
How does this epidermis looks like? In most cases, The epidermis is single layered. It is mostly flat and it forms a continuous layer without any intracellular spaces.
Do all plants have same type of epidermis? No. The plants that need extra protection, they have a different epidermis. The epidermis of plants living in extreme dry habitats like cactus, they have a thicker epidermis with multiple layers.
This thicker epidermis prevents the loss of water. Which parts of the plant are covered by epidermis? All parts of the plant are covered by epidermis. But there is a difference between the epidermis covering the shoot system and the epidermis of root system.
What are the special features of epidermis present on the aerial parts of the plant, i.e. the shoot system of the plant? The epidermal cells the aerial parts of the plant secrete a waxy water resistant layer on their outer surface. This waxy layer is called cuticle.
It protects the plant parts from excess loss of water, mechanical injury and from parasitic fungi. Epidermis present on the leaf has small pores here and there. These pores are called stomata and each stomata is protected by a pair of kidney shaped guard cells.
Do you know the function of this stomata? This stomata has two functions. 1. Stomata are essential for exchange of gases and 2. They help in the process of transpiration. How are the epidermal cells of root system? The epidermal cells of roots bear long hair like structures.
These hairs greatly increase the total absorbative surface area. That means these hairs helps to absorb more water. In big trees, the epidermis on the stem surface is replaced with dead cork cells. These cells have a chemical called subarin which prevents the entry of water and gases into the stem.
This is all about the epidermis in plants. Now, let us learn about Complex permanent tissues in plants. Do you know what is the difference between simple permanent tissue and complex permanent tissue?
Here are two flower bouquets. Can you spot the difference between them? Yes, bouquet A is made of same kind of flowers and bouquet B is made up of different type of flowers. In the same way simple permanent tissue is made up of similar kind of cells, whereas the complex permanent tissue is made up of more than one type of cells.
Even though there are different types of cells exist in one tissue, they all work together for a common function. The complex permanent tissues in plants are of two types. 1. Xylem and 2. Phloem.
What are the features and functions of xylem tissue? Xylem consists of tracheids, vessels, xylem parenchyma and xylem fibers. Tracheids and vessels are tubular structures that have thick cell wall. When these cells mature, they become dead cells. Xylem tissue transports the water and minerals from roots to different parts of the plant.
Xylem parenchyma stores the food and the xylem fibers, they give support to the plant. What are the features and functions of phloem tissue? Phloem is made up of five types of cells. They are sieve cells, sieve tubes, companion cells, phloem fibers and phloem parenchyma.
Sieve tubes are tubular cells. Their cell walls are perforated. Phloem fibers are dead cells.
Remaining all phloem cells are living cells. Do you know the function of phloem tissue? Phloem transports food from leaves to other parts of the plant.
Xylem and phloem join together to form a vascular bundle. These two are called as the conducting tissues of plant. This is all about the complex permanent tissues in plants. Epithelial tissue.
Now, let us learn about epithelial tissue. What is epithelial tissue? The covering or protective tissue in animals is called epithelial tissue. Do you know?
Which organs in our body are protected by epithelium? Almost all organs and their inner cavities are covered by epithelium. The outer as well as inner surface of the organs like stomach, blood vessels are covered by epithelium. Cavities like mouth cavity and nasal cavity are also covered or lined by epithelium.
The alveoli of lungs and renal tubules of kidneys are made up of epithelial tissue, not only the internal parts. Our body's external surface is also covered by a kind of epithelium, that is our skin. So, skin is also a kind of epithelium.
Now let us see the features of epithelial tissue. Epithelial tissue is a continuous sheet of cells. They are tightly packed without any intercellular spaces. The cementing material between the cells is also very less.
The epithelial tissue is separated from the underlying tissue by an extracellular fibrous basement membrane. Now let's see the importance of epithelial tissue. Anything from the outer atmosphere has to enter our blood or anything that has to leave our blood should pass through the epithelium at least once.
For example, alveoli is the part of lung where the exchange of gases takes place. Oxygen from the air that we breathe in enters the blood and the carbon dioxide in the blood comes into the alveoli. So here, the oxygen and carbon dioxide, they crosses the walls of alveoli and blood vessel. The wall of alveoli and the wall of blood vessel are made up of single layer of epithelial cells.
So, the epithelium plays an important role in regulating the exchange of materials between the body and external environment. So, this is about the features of epithelial tissue. Now, let us learn about different types of epithelial tissue. Epithelial tissue is of different types. depending upon their structure and functioning.
The first one is simple squamous epithelial tissue. Let us see the features of simple squamous epithelial tissue. This tissue has a single layer of cells.
These cells are extremely thin and flat. This tissue forms the delicate lining of many internal organs of our body. Can you give a few examples of organs in which we find simple squamous epithelial tissue? The lining of blood vessels and the lining of esophagus, lining of mouth are made of simple squamous epithelial tissue.
The internal organs like stomach and kidneys are made up of muscles, but their cavities are lined internally by simple epithelial tissue. Do you know, certain parts of our body systems are completely made up of simple squamous epithelium. The blood capillaries and the alveoli of lungs are made up of simple squamous epithelial tissue. Do you know why these parts are completely made up of simple squamous epithelial tissue?
Because these parts, they play an important role in exchange of materials between the body's internal environment and external environment. For example, the air in the alveoli contains oxygen. It has to cross the wall of alveoli and wall of blood capillary to enter our blood circulatory system.
Since these walls are made up of simple squamous epithelial tissue, the oxygen can easily enters our bloodstream. In the same way, carbon dioxide from our blood reaches the alveoli and get exhaled out. Our skin is also a squamous epithelial tissue.
But it is not simple type. It is... Stratified.
Stratified means layered. Our skin is made up of squamous epithelial tissue that is in many layers. Hence it is called stratified squamous epithelial tissue. Why the skin has epithelium in many layers?
Because the epithelial cells of skin are arranged in layers to prevent wear and tear. So the squamous epithelial tissue is of two types. 1. Simple squamous epithelial tissue and stratified squamous epithelial tissue.
Examples of simple squamous epithelial tissue are lining of mouth, lining of esophagus, alveoli, blood capillaries. Examples of stratified squamous epithelium is skin. This is about squamous epithelial tissue. Now, let us learn about cuboidal.
and columnar epithelial tissue. First let us learn about cuboidal epithelial tissue. Where do we find this cuboidal epithelium in our body? We find this tissue as a lining of kidney tubules and ducts of pancreas and salivary glands.
What are the functions of cuboidal epithelium? The cells of this epithelial tissue looks like cubes. So it is called Cuboidal epithelium. It provides mechanical strength. The other important function of cuboidal epithelium tissue is secretion.
Sometimes, cuboidal epithelial cells specializes into gland cells and secrete different substances. Sometimes, cuboidal epithelial tissue folds inwards and forms a multicellular gland. This kind of Cuboidal epithelium is also called as glandular epithelium.
Cuboidal epithelium present in the kidney tubules and in the lining of intestine helps in the absorption of materials. The next one is columnar epithelium. Columnar means pillar-like.
These cells look like pillars. So this tissue is called columnar epithelial tissue. Where do we find this columnar epithelium in our body? This tissue is mostly found in the lining of stomach, small intestine and large intestine.
What are the functions of columnar epithelial tissue? The primary function of columnar epithelial tissue is absorption and secretion. The columnar epithelial tissue present in the inner lining of stomach secretes acid digestive enzymes and mucus.
The columnar epithelial tissue present in the lungs has cilia that helps in the upward movement of mucus that is formed in the lungs. Thus, columnar epithelial tissue also helps in the movement of materials. The columnar epithelial tissue with cilia is called as ciliated columnar epithelial tissue.
This is all about Cuboidal and columnar epithelial tissue Now, let us learn about connective tissues. What is connective tissue? The tissue that connects different tissues or organs and gives structure to other tissues and organs is called connective tissue. Blood, bones, cartilage are the examples of connective tissue. Blood is a fluid connective tissue.
that connects the different parts of the body. Bone is another connective tissue that gives shape and support to the body. What are the common features of connective tissue? The cells of the connective tissue are loosely spaced.
They are embedded in an intercellular matrix. The matrix of blood is like a fluid whereas The matrix of bone is very hard. Now let us study some important connective tissues in our body.
First let us see about blood. Blood is a fluid connective tissue. Blood has different types of cells like RBC, WBC and platelets. These cells are suspended in a fluid matrix called plasma.
The plasma contains proteins, salts and hormones. Do you know the functions of blood? It transports nutrients, gases, hormones and waste materials between different parts of the body. Now let us see the other type of connective tissue that is bone. Bone is a strong and non-flexible tissue.
The cells of the bone are embedded in a hard matrix that is composed of calcium and phosphorus compounds. What are the functions of the bone? It forms the supportive framework of our body.
It holds the muscles tight and helps in movement. It forms hard cases and protects the sensitive internal organs. We have learnt about blood and bone.
Now let us see some differences between blood and bone. Blood is a fluid connective tissue whereas bone is a strong non-flexible tissue. The blood connects different parts of the body whereas the bone gives shape and support to the body. Blood has cells like RBC, WBC and platelets.
The bone has cells called as osteocytes. The matrix of blood is in fluid state and is called as plasma. It is composed of water, proteins, salts and hormones.
The matrix of bone is hard and is made up of calcium and phosphorus compounds. This is all about blood and bone. Now, let us learn about ligaments, tendons, cartilage, areolate connective tissue. and adipose tissue. First let us see about ligament.
Ligament is a kind of connective tissue that connects two bones together. This tissue is very elastic and has considerable strength. Ligament has very little matrix.
These are the locations of ligament in our body. Now let us see the next one, tendons. Tendon is a kind of connective tissue that connects the muscle to a bone.
The matrix of tendon has so many fibers. It has great strength and limited flexibility. These are a few locations of tendons in our body. Now let us see about cartilage. We have a soft bone at the tip of our nose, ear flaps etc.
This soft flexible bone like material is called cartilage. It is a kind of connective tissue. The cells of the cartilage are widely spaced. The matrix of cartilage is composed of proteins and sugars. The surface of the bones at the joints are smoothened by cartilage.
Cartilage is also found in nose, ear, trachea and larynx. The next one is areolar tissue. This tissue is present between skin and muscles. It wraps the blood vessels and nerves.
It is also present in the bone marrow. What are the functions of the areola tissue? It fills the space inside the organs. It also helps in the repair of the tissues. Now, we will see the another type of connective tissue, adipose tissue.
Oedipus tissue is found below the skin and between internal organs. The oedipus tissue contains the cells called as oedipocytes. These cells are filled with fat globules.
The main function of this tissue is to store fats. It also acts as an insulator of heat. This is all about the connective tissues in animals.
Muscular tissue Now, let us learn about muscular tissue. What are the features of muscular tissue? The cells of the muscular tissue are elongated.
These cells are also called as muscle fibers. Muscle cells contain special proteins called as contractile proteins. The muscles are able to contract and relax due to these proteins. What are the functions of muscular tissue?
Muscular tissue gives shape, support and causes movement in different parts of our body. Now let's see the types of muscles. Muscles are of three types. 1. Voluntary muscles 2. Involuntary muscles 3. Cardiac muscles First let us learn about Voluntary Muscles.
These muscles are under the control of our conscious will. That means we can contract or relax our muscles at our will. Example, muscles of our hands and legs. Voluntary muscles are also called as skeletal muscles or striated muscles. First let us know why they are called as skeletal muscles.
Because most of the voluntary muscles are attached to the skeletal system and helps in the body movement. Hence, they are called as skeletal muscles. What are the features of voluntary muscles? If the muscle fibers of voluntary muscles are stained and observed under microscope, we find striations.
Do you know what are striations? Striations means dark and light bands. That is why these voluntary muscles are also called as striated muscles. The cells of this tissue are long, cylindrical and there is no branching observed.
These cells are multi-nucleated, that means they have many nuclei. So in a nutshell, the voluntary muscle cells are long, cylindrical, unbranched, multi-nucleated and striated. Now we will see the another type of muscular tissue called as involuntary muscles. These muscle movements are not under our will. That's why they are called as involuntary muscles.
What are the features of these involuntary muscles? The cells are long with pointed ends. They look spindle shaped and uninucleated means only one nucleus per cell.
There are no dark and light bands. like the voluntary muscles. Hence, they are also called as unstriated muscles. Where do we find these unstriated muscles in our body? The involuntary muscles are found in the elementary canal, blood vessels, iris of the eye, urinary bladder, uterus and bronchi of lungs.
The involuntary movements like movement of food in the elementary canal and the contraction and relaxation of blood vessels carried out by the involuntary muscles. So the involuntary muscles are also called as unstriated muscles and smooth muscles. Now we will see the other type of muscular tissue known as cardiac muscle or heart muscle.
The heart muscle cells are cylindrical and branched and uni-nucleated that means only one nucleus. They have striations but They are involuntary in nature. They are present in the heart.
Cardiac muscle creates arrhythmic contraction and relaxation of the heart. This is all about the muscular tissue. Nervous tissue Now, let us learn about nervous tissue.
Where do we find nervous tissue in our body? Nervous tissue is found in the organs like brain, spinal cord and nose. The cells of the nervous tissue are called neurons or nerve cells.
Let us see the parts of a nerve cell. This is the cell body of a neuron. This is the nucleus and these short processes that arise from the cell body are called dendrites.
There is a long hair like projection or process that arise from the cell body is called axon. What is the difference between a nerve and a nerve cell? Nerve is a bundle of nerve cells, many nerve fibers bound together by connective tissue and make up a nerve. What is the function of nervous tissue? Nerve cells carry the information in the form of electric impulses.
They are also called as nerve impulses. Nerve cells perform two main functions. 1. Carrying the impulse from sense organs to brain or spinal cord and Carrying the impulses from brain or spinal cord to muscles. Nervous tissue helps the animals in responding quickly to the stimulus.
This is all about the nervous tissue. Thanks for watching. Please like the video. Please share this video with your friends.
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