Question

Answer the following for 99 points
1. Describe the structure and functions of various types of epithelial tissues.
2. Classify and explain various types of muscles with the help of suitable diagrams.
3. Define simple tissue classify and explain its different types with the help of suitable diagrams.
4. Classify connective tissues and their functions and locations.
5. Make a flow chart to explain various types of tissues in plants.

Answer 1

Answer:

Muscle tissue is characterized by properties that allow movement. Muscle cells are excitable; they respond to a stimulus. They are contractile, meaning they can shorten and generate a pulling force. When attached between two movable objects, in other words, bones, contractions of the muscles cause the bones to move. Some muscle movement is voluntary, which means it is under conscious control. For example, a person decides to open a book and read a chapter on anatomy. Other movements are involuntary, meaning they are not under conscious control, such as the contraction of your pupil in bright light. Muscle tissue is classified into three types according to structure and function: skeletal, cardiac, and smooth (Table 1).

Answer 2

1. There are three principal shapes of epithelial cell: squamous, columnar, and cuboidal. These can be arranged in a single layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells deep as stratified (layered), either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due to the placement of the nuclei. This sort of tissue is called pseudostratified. All glands are made up of epithelial cells. Functions of epithelial cells include secretion, selective absorption, protection, transcellular transport, and sensing.

2. 3 Types of Muscles
Cardiac muscle:
The cardiac muscle is a type of involuntary striated muscle found in the walls of the heart. As it contracts, it propels blood into the heart and through the blood vessels of the circulatory system.
Skeletal muscle:
The skeletal muscle is a type of striated muscle, usually attached to the skeleton. Skeletal muscles are used to create movement, by applying force to bones and joints; via contraction. They generally contract voluntarily (via somatic nerve stimulation), although they can contract involuntarily through reflexes. The whole muscle is wrapped in a special type of connective tissue, epimysium.
Smooth muscle:
The smooth muscle is a type of non-striated muscle, found within the tunica media layer of arteries and veins, the bladder, uterus, male and female reproductive tracts, gastrointestinal tract, respiratory tract, the ciliary muscle and iris of the eye. The glomeruli of the kidneys contain a smooth muscle-like cell called the mesangial cell. Smooth muscle is fundamentally different from skeletal muscle and cardiac muscle in terms of structure, function, excitation-coupling, and mechanism of contraction.

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Dr. P.S. Verma & Dr. V.K. Agarwal

PS Verma and VK Agarwal Biology Class 9 Solutions

PS Verma and VK Agarwal Biology Class 9 Solutions Chapter 3 - Tissues

Question

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Q. 3

What is simple tissue? Classify and explain its Different types with suitable diagram.

Answer

Simple tissue: Three types of simple tissues occur in plants:

(a) Parenchyma (b) Collenchyma (c) Sclerenchyma


(a) Parenchyma: It is a simple, permanent living tissue which is made up of thin-walled cells. The cells of this tissue are oval, elongated, and loosely packed with large intracellular space. Their cell wall is made up of cellulose. Each cell encloses a large central vacuole, cytoplasm and a prominent nucleus.


The parenchyma tissue is present in soft parts of the plant such as cortex, pith, palisade and some parts of the flower.


Parenchyma tissue provides support to plants and also stores food. In some situations, it contains chlorophyll and performs photosynthesis.





(b) Collenchyma: It is a another type of simple permanent tissue which is found few layer below the epidermis of leaves and stem. The cells of this tissue are living, elongated and tightly packed with no inter-cellular space. The cells have small nucleus, large vacuoles and thin cell wall but irregularly thickened at the corners.


Collenchyma tissue provides flexibility to plants so that they can easily bend without breaking. It also provides mechanical support to plants.





(c) Sclerenchyma: It is a supporting tissue. It is the tissue which make plant hard and stiff.


Location: This tissue is present in stems, around vascular bundles, in the veins of leaves and in the hard covering of seeds and nuts.


Structure: The cells of this tissue are dead. They are long, elongated, narrow, thick walled and lignified. These consists of fibres and sclereids.


It provides strength to the plants and enables them to withstand various strains.