Animal/ Plant cell
Plant Cells
Plants are eukaryotic organisms whose cells acquire specialized functions as they mature
Types of Cells in Plants
Parenchyma Cells - They compose the middle layer of leaves and the inner and outer layers of stems and roots. Soft tissues of fruits are also made form parenchyma cells
Collenchyma cells - They are elongated cells with thick cell wall whose main functions are for support and structure especially in young plants.
Sclerenchyma cells - They also have a support function but are much more rigid than collenchyma cells. They are thick and come in many shapes.
Plant Tissues - Plant tissues are groups of cells with a common structure, function, or both. The key tissues among plants are the vascular, dermal and ground tissues.
Parts of Plant Tissues
Vascular Tissues - Group of cells that conduct the movement of nutrients and water.
Dermal Tissues - Outer protective covering of plants.
Ground Tissues - Tissues which are neither vascular nor dermal, they are for storage of carbohydrates which plants need for growth.
Vascular Tissues - They the primary tissues of plants responsible for the transport of nutrients and water They are found only in-vascular plants because they have lignified tissues throughout the plant which allow the transport of substances. The primary components of vascular tissue are the xylem and the phloem
Dermal Tissues - The cells that compose dermal tissues serve as the outer protective layer of plants. By way of analogy, they are like the skin of plants which serve as the first layer of protection against harmful elements of the environment.
Components of Dermal Tissues
Epidermis - A single layer of tightly packed cells that cover and protects the plant.
Periderm - Commonly referred to as the bark, it is a multi-layered dermal tissue composed of cork cells (phellem). phelloderm, and cork cambium (phellogen)
Ground Tissue - Tissues which make up the plant but are neither vascular nor dermal tissues comprise the ground tissue. They can be found inside and outside the ring of vascular tissue in the plant stem. The three types of cells that compose the ground tissue are the parenchyma cells, collenchyma cells, and sclerenchyma cells
Meristematic Tissues - Another prominent category of cells among plants is the meristematic tissue. It is a collection of young cells which are continuously reproducing through division. They are mostly found ate the apices of root and shoot and are embedded in the vascular tissues which contribute to the increase in the girth size of roots and stems.
MERISTEMATIC TISSUES BASED ON POSITION
Apical Meristem- Cells found at the growing regions of roots and shoot and contribute to increase in length.
Lateral Meristem- Cells found in the vascular tissues and contribute to the increase in thickness of a plant part.
Intercalary Meristem - Cells found in regions between mature tissues of the plant such as at the base of leaves or at the base of internodes of grasses.
Basic Animal Cells
Skin Cells - Consists of keratinocytes and melanocytes Keratinocytes make up 90% of all skin cells. They produce a protein called keratin Melanocytes produce melanın which gives color to skin.
Muscle Cells - Myocytes or muscle cells are long tubular cells that help organisms move their limbs and organs.
Blood Cells- Blood cells can be either red blood cells or white blood cells. Red blood cells make up 999% of all blood cells and delivers oxygen to different parts of the body. White blood cells find and destroy pathogens and other harmful substances in the body
Fat Cells - Adipocytes or lipocytes are storage cells for fats and lipids which are reserves of energy
Nerve Cells,- Neurons are the main cells of the nervous system. They carry messages & deliver signals to different parts of the body using their dendrites & axon.
Bone Cells- Osteocytes are majority of cells embedded within the substance of a fully formed bone
Epithelial Tissues Based on Shape and Function
Squamous Epithelium-
* **Definition**: Flat & thin cells with no intercellular spaces between cells.
* **Location**: Found in the outer layer of the skin, in the lining of cavities, blood vessels, and in the chambers of the heart.
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#### **Columnar Epithelium-
* **Definition**: Cylindrical in shape, it facilitates the movement of nutrients across the epithelial barrier.
* **Location**: Found in the lining of stomach and intestines.
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#### **Glandular Epithelium-
* **Definition**: It forms from a columnar epithelial cell, it secretes substances.
* **Location**: Found in the sweat glands of the skin and tear glands of the eye.
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#### **Ciliated Epithelium-
* **Definition**: A columnar cell with hair-like projections called cilia. Cilia push the mucus forward into the nasal tract to clear it.
* **Location**: Found in the lining of the respiratory tract.
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#### **Cuboidal Epithelium-
* **Definition**: Cube-like in shape, it provides mechanical support to organs.
* **Location**: Found in the lining of kidney tubules, salivary glands, & thyroid glands.
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Stratified Epithelium-
* **Definition**: Form layers of epithelial cells composed of one or different types of epithelial cells.
* **Location**: Found in the epidermis of the skin, lining of the mouth cavity and esophagus.
Animal Tissues- A group of cells in animals that share a similar structure and perform the same function is called an animal tissue.
TYPES OF ANIMAL TISSUE
Epithelial Tissue - Covers body surfaces and lines body cavities, some epithelial cells secrete glands.
Connective Tissue - Binds and supports body parts.
Muscular Tissue- Long cylindrical fibers arranged in parallel arrays which allows the parts of the body to move.
Nervous Tissue- Receives, processes, and transmits information from one part of the body to another.
Epithelial Tissue - It forms a protective layer of cells for organs. They serve as a barrier to keep the body systems separate. The most visible epithelial tissue is our skin which protects our internal organs from harmful agents of environment.
Connective Tissue - Connective tissue is a network of cells that connects and binds different tissues and organs of the body
Types of Epithelial Tissue Based on Structure:
Simple epithelial tissue - Composed of a single layer of cells. It functions as a lining of cavities, ducts, and tubes.
Compound epithelial tissue- Composed of two or more layers of cells. It functions as a protective covering. Our skin is a compound epithelial tissue.
Epithelial Tissues Based on Shape and Function:
**Squamous epithelium**
Flat & thin cells with no intercellular spaces between cells.
Found in the outer layer of the skin, in the lining of cavities, blood vessels, and in the chambers of the heart.
**Columnar epithelium**
Cylindrical in shape, it facilitate the movement of nutrients across epithelial barrier.
Found in the lining of stomach and intestines.
**Glandular epithelium**
It forms from a columnar epithelial cell, it secretes substances.
Found in the sweat glands of the skin and tear glands of the eye.
**Ciliated epithelium**
A columnar cell with hair-like projections called cilia. Cilia push the mucus forward into the nasal tract to clear it.
Found in the lining of the respiratory tract.
**Cuboidal epithelium**
Cube-like in shape, it provides mechanical support to organs.
Found in the lining of kidney tubules, salivary glands, & thyroid glands.
**Stratified epithelium**
Form layers of epithelial cells, composed of one or different types of epithelial cells.
Found in the epidermis of the skin, lining of the mouth cavity and esophagus.
Blood – A fluid connective tissue composed of plasma, RBC, WBC & platelets. It flows through blood vessels carrying oxygen, nutrients, hormones, & antibodies to different parts of the body.
Location: (Found in blood vessels)
Bone – Bone cells are embedded in a matrix composed of calcium & phosphorous compounds. They are hard & porous. They anchor muscle tissues, protect internal organs, & give mechanical support to the entire body.
Location: (Found in bones)
Fibrous connective tissues (ligaments & tendons) – Ligaments connect two bones. Tendons connect bones to the muscles. They add strength to muscles.
Location: (Found in ligaments and tendons)
Muscle Tissue - Because of their elasticity and flexibility, it allows animals to move. They have elongated cells called muscle fibers.
Nervous Tissue - The nervous tissue receives, processes, and transmits information from one par of the body to another. The two cells that make up the nervous tissue are the neurons and glial cells, also called neuroglia. Neurons join end to end to form a nerve fiber. Nervous tissues form the brain, spinal cord, and nerves. The combination of nerves and muscles allow organisms to act in response to stimuli.
Some Specialize Cells in Plants:
Guard cells - Found in leaves, they surround and control the opening and closure of the stoma in response to changes in temperature and scarcity of water. Guard cells come in pairs.
Root Hairs - Part of the dermal tissue of roots. They add to the surface area of roots and increase their absorptive capacity.
Tracheids - Elongated cells in the xylem of vascular plants that aid in transporting water and nutrients from the root's top other parts of the plant.
Palisade cells (leaf cells) - Cells designed for photosynthesis; they contain a structure called chloroplast which contains green pigments called chlorophyll. Chlorophyll absorbs light energy from the sun.
White blood cells (leukocytes) – Identify and destroy pathogens. They contain granules that engulf and digest bacteria and have a long, narrow shape that helps them pass through narrow gaps.
Microvilli (singular: microvillus) – Finger-like projections found on the intestinal wall that increase surface area and enhance the intestine's ability to absorb nutrients.
Ciliated epithelial tissue – Made up of cells with hair-like projections (cilia) that help move mucus along the respiratory tract, clearing the airway.
Some Specialized Cells in Animals – These are cells adapted to perform specific functions, such as white blood cells for immune defense and epithelial cells for clearing airways or absorbing nutrients.
Striated Muscle – Cylindrical in shape and contains many nuclei. Each muscle fiber has alternating dark and light-colored bands called striations. Helps animals move limbs and lift objects. It is a voluntary muscle. Found in limbs, hands, main body trunk, face, and neck.
Smooth Muscle – Has the shape of a spindle, and has one nucleus, with no striations. It moves food down the esophagus, stomach, and through the intestines. It is an involuntary muscle. Found in the alimentary canal, eye, urinary bladder, and bronchi of the lungs.
Cardiac Muscle – Branched muscle, cylindrical in shape with a single nucleus. Its contraction and relaxation produce heartbeats which force blood to circulate. It is an involuntary muscle. Found in the heart.
Cartilage – Widely spaced cells suspended in a matrix of protein and sugars. Adds mechanical support and flexibility. Found in nose, ears, trachea, & at the end of long bones for flexibility.
Areolar connective tissue – Cells that fill the space inside organs and give them mechanical support. Found between skin and muscles, around blood vessels and nerves.
Adipose connective tissue – Filled with fat globules, they act as an insulator. Found below the skin, around internal organs.
Cartilage – Widely spaced cells suspended in a matrix of protein and sugars. Adds mechanical support and flexibility. Found in nose, ears, trachea, & at the end of long bones for flexibility.