Plant and Animal Tissues

• Tissue is a group of similarly modified cells with a common origin performing specific functions.

Plant Tissues

• Plant tissues exist in different forms.
• They are categorized into two groups: meristematic and permanent, based on cell division ability.

Meristematic Tissues

• The cells actively divide through mitosis to produce new cells.
• New cells, which are undifferentiated contribute to plant growth.

Features of Meristematic Tissues

• Consist of small, living cells.
• Have indistinct intercellular spaces.
• Contain a prominent nucleus.
• Lack a large central vacuole; small vacuoles may be present.
• Contain a high number of mitochondria. Meristematic tissues are usually present in varying locations in the plant.

Apical meristems

• Found in shoot, root apex, and axillary buds, and enhances the plant's height.

Intercalary meristems

• Discovered at nodes and responsible for internode elongation and mostly observed in grass families.

Lateral meristems

• They are located laterally in the stems and roots and increase the plant's diameter along its longitudinal axis.
• Cambium tissue in dicots is a lateral meristematic tissue.

Permanent Tissues

• These are tissues that have lost the ability to divide and perform a specific function.
• They are categorized into simple and complex tissues.

Simple Permanent Tissues

• Composed of similar cells and includes parenchyma, sclerenchyma, and collenchyma.

Parenchyma

• Forms the soft parts of the plant, and are the most abundant type of tissue in the plant.

Features of Parenchyma Tissue

• Composed of living cells.
• Cells possess a spherical shape and a huge central vacuole.
• The nucleus is located peripherally in the cytoplasm.
• Comprised of thin cellulose.
• Intercellular spaces are present.

Locations of Parenchyma Tissues

• In the cortex and pith of plant stems and roots.
• Found in fleshy fruit parts and leaves (mesophylls).
• Located in seeds (endosperm).

Functions of Parenchyma Tissue

• Photosynthesis occurs in palisade and spongy mesophyll, which contain chloroplasts.
• Stores food and may be known as storage tissues in roots, tubers etc..
• Xerophytes store water in parenchyma tissue in leaves and stems.
• Herbaceous plants which contain Balsam are capable of absorbing water which provides mechanical function

Collenchyma

• Provides mechanical strength and support, and are formed from modified parenchyma cells.

Features of Collenchyma Tissue

• Composed of living cells containing cytoplasm, a nucleus, and a central vacuole.
• Generally elongated and polygonal in cross-section.
• Cell wall corners are thickened, and intercellular spaces may or may not be evident.

Locations of Collenchyma

• Forms a cylindrical tissue towards the inner herbaceous stems, and also in the veins of dicot leaves.

Functions of Collenchyma

• Offers mechanical support to dicot plant stems before wood formation.
• Reinforces plant leaves in the veins, and photosynthesis is carried out by the chloroplasts in dicot stems.

Sclerenchyma

• Offers mechanical strength and support.

Features of Sclerenchyma Tissue

• Contains dead cells.
• Cellulose cell walls have lignin deposits.
• Tightly packed cells with no intercellular spaces.
• Cell walls are thickened and form a central lumen.

Locations of Sclerenchyma Tissue

• Xylem fibers and pholem fibers (fibres are present in them)
• Coconut fibres, agave fibres, and cotton wool.
• Endocarp of fruits such as coconut, camphor, mango, guava, pear, coffee and dates.

Functions of Sclerenchyma

• Provides support to the plant body.

Complex Permanent Tissues

• Formed when different cell types combine.

Xylem

• Transports water and pholem within the vascular systems of the stems, roots, and leaves. Consisting of four main cell types like vessel elements and tracheids.
• Fibres and Parenchyma

Functions of Xylem Tissue

• They help transport water and all minerals to the plant body using both absorbed plant roots
• Mechanical support is offered to support the plant body.

Phloem

• Consists of tube elements, companion cells, fibres(pholem) and Parenchyma

Functions of Phloem Tissue

• Transports synthesized food to plant body.

Animal Tissues

• The human body for instance has 210 different types of tissue made with cells.

Common Animal Tissue types

• Epithelial, Connective, Muscle and Nervous tissue are types of animal tissue with specific functions.

Epithelial Tissue

• It lines the free internal and external surfaces of the vertebrate body.
• Some are composed of one cell layer while others are composed of several layers.

Features of Epithelial Tissues

• Arranged on base membranes
• Very compact and dense

Functions of Epithelial Tissues

• Offers protective, absorption, filteration and protective qualities

Connective Tissue

• Consists of varying cell types and made up of fibres which are arranged in a matrix.
• These tissues provide support, connection between most organs tissues.

Blood Tissue

• It is a type of special connective tissue in which no cell secrets the matrix(plasma).

Features of Blood tissue

• Consists of matrix/ fluid called cells.
• The fluid contains red and white blood cells
• During clotting platelets help form

Functions of Blood Tissue

• Transports hormones, respiratory gases, and nutrients to relevant organs.
• Fights against foreign bodies by use of "whte blood cells."

Muscle Tissue

• It contains cells and muscle fibres which contract, relax, and move
• There are three main types of muscle tissue.

Three Types of Muscle Tissue

• Smooth
• Skeletal
• Cardiac

Smooth Muscle Tissue

• Found in the walls of organs like bladder and blood vessels.
• Contains cells which are smooth, spindle-shaped, and one nucleus in the centre.

Skeletal Muscle Tissue

• It helps skeletal muscles control movement for both movement in the chordates

Features of Skeletal Muscle Fibres

• They can easily become fatigue
• The help make-up the limbs and body for ease of movement

Cardiac Muscle Tissue

• Contains cells which are striated short cell that do not become fatigue due to rhythmic contractions

Nervous Tissue

• The tissue is responsible for impulse transmissions and a core component especially in chordates.

Features of Neuron

• The tissue is responsible for impulse transmissions and a core component especially in chordates.
• Nuclei and mitochondria are present inside the neuron

Neuron Function

• The nervous cells are responsible for transmitting stimulus from the receptor sites to all effectors.