In tissue, cells have a similar structure and perform a specific function together. An old French verb means “to weave” is the origin of the word tissue. An animal’s tissues can be divided into four categories: connective, muscular, nervous, and epithelial.
It is possible to divide plant tissues into three types: vascular, ground, and epidermal. In the body, organs such as the brain and heart are composed of groups of tissues.
Types of Animal Tissues
Groups of tissues are connected or separated by connective tissue. It is located between all the other tissues and organs in the body. Ground substance surrounds cells in connective tissue, which is made of cells and a gel. In addition to lymph and blood, most connective tissues also contain fibers, which are long, narrow proteins.
Collagenous fibers bind bones to tissues, elastic fibers allow organs like the lungs to move, and reticular fibers support cells physically. Oxygen can also diffuse from blood vessels into cells through connective tissue.
One in ten people suffers from a connective tissue disorder. The most common connective tissue disorders are sarcomas, Marfan syndrome, lupus, and scurvy, which leads to fragile connective tissue due to a Vitamin C deficiency.
The specialized nature of muscle tissue is what allows muscles to contract, and it comprises all the muscles in the body. Muscle tissue can be divided into three types: skeletal muscle, cardiac muscle, and smooth muscle. The skeletal muscle anchors tendons to bones and allows the body to move. The heart’s cardiac muscle pumps blood through the body.
Besides being found in the intestines, where smooth muscle helps move food through the digestive tract, smooth muscle is also found in blood vessels, the uterus, and the bladder. As sarcomeres (a unit of muscle tissue) are arranged uniformly, skeletal and cardiac muscles are striated. Sarcomeres do not exist in smooth muscle.
Muscle tissue disorders include Duchenne muscular dystrophy. Over time, it causes muscles to atrophy due to an inherited disease. When muscles atrophy, they shorten, causing scoliosis and immobility. Due to the fact that the gene responsible for the disorder is located on the X chromosome (which males have only one copy of), individuals with this disorder are usually males.
All parts of the nervous system contain nervous tissue, including the brain, spinal cord, and peripheral nerves. Neurons and neuroglia, which assist nerve impulses in traveling, make up the nerve cell. In the brain, gray matter and white matter are classified as gray matter; in the peripheral nervous system, nerves and ganglia are classified as white matter.
In gray matter, neurons have unmyelinated axons, while in white matter, they have myelinated axons. An essential component of the nervous system is myelin, which is a white, fatty substance that insulates neurons.
Alzheimer’s disease is characterized by memory loss, mood swings, and confusion caused by the breakdown of nervous tissue. Another disease that degenerates nerve tissue is Amyotrophic Lateral Sclerosis (ALS).
As a result, higher brain functions are lost over time. Multiple sclerosis, in which the immune system attacks and destroys nervous tissue, Huntington’s disease, where an abnormal protein causes neuron death, and Parkinson’s disease, in which there is too little dopamine in the brain that controls movement, are some of the neurological disorders.
A skin cell, a tracheal cell, a reproductive cell, and the lining of the digestive tract all have epithelial tissue on their surfaces. It protects organs, absorbs water and nutrients, gets rid of waste, and secretes enzymes and hormones. Epithelium forms all of the body’s glands.
Eczema and psoriasis, both of which cause rashes, are examples of epithelial tissue diseases. The term carcinoma refers to cancer that arises from epithelial tissue. Asthma, which results in shortness of breath due to inflammation of the airways, is also caused by epithelial cells in the airways.
Types of Plant Tissues
In plants, vascular tissues transport substances from one part of the plant to another. Both xylem and phloem make up vascular tissue. A plant’s xylem transports water and some soluble nutrients, while its phloem transports organic compounds, particularly sucrose. As nutrients are transported through vascular tissues, they form long, thin cylinders.
Additionally, vascular tissue contains two types of meristems, which are tissues that contain undifferentiated cells for plant growth. The cork cambium and the vascular cambium are meristems that accompany vascular tissue. The growth of a plant’s vascular tissues is regulated by these meristems.
The ground tissue consists of all cells that do not belong to the vascular or dermal systems (epidermis; see below). Ground tissue consists of three types: parenchyma, collenchyma, and sclerenchyma. In plants, parenchyma cells serve many functions, including photosynthesis, storing starch, fats, oils, proteins, and water, and repairing damaged tissues.
An organ’s structure is supported by long, irregularly thick cells called collenchyma tissue. In windy areas, collenchyma tissue is thicker on plants. The sclerenchyma is also a support tissue, but it is composed of dead cells. The two types of sclerenchyma are fibers and sclereids. Sclereids are star-shaped cells with thick walls, whereas fibers are long, slender cells. Textiles such as hemp and flax are made from sclerenchyma fibers.
Roots, stems, leaves, and flowers are covered by the epidermis, which consists of a single layer of cells. The epidermis protects the plant from water loss, regulates carbon dioxide and oxygen exchange, and absorbs water and nutrients from the soil in roots.
A plant’s stems and leaves have pores called stomata, through which carbon dioxide, water vapor, and oxygen diffuse. The plant’s epidermis is protected from water loss by its cuticle, which contains mostly cutin, a waxy substance. In deserts and other arid regions, plants often have thick cuticles to conserve water.
Related Biology Terms
- Tissues are formed by groups of cells, which are the basic unit of life.
- In the body, an organ is a self-contained group of tissues that performs a specific function.
- Myosin and actin filaments are found in striated muscle tissue called a sarcomere.
- At the tips of roots and stem offshoots, meristems are regions of undifferentiated plant tissue.
There are four main types of animal tissues: epithelial tissue, connective tissue, muscle tissue, and nervous tissue.
Epithelial tissue is a type of tissue that covers the surfaces of the body, both inside and outside. It acts as a protective barrier against physical damage, bacteria, and other harmful substances.
Connective tissue is a type of tissue that connects, supports, and anchors different parts of the body. It includes bone, cartilage, blood, and adipose (fat) tissue.
Muscle tissue is a type of tissue that is responsible for movement in the body. There are three types of muscle tissue: skeletal muscle, which is attached to bones and is responsible for voluntary movement; smooth muscle, which is found in the walls of internal organs and is responsible for involuntary movement; and cardiac muscle, which is found in the heart and is responsible for pumping blood.
Nervous tissue is a type of tissue that is responsible for transmitting and processing information in the body. It includes neurons, which are specialized cells that transmit electrical signals, and supporting cells called glia, which provide structural and metabolic support for neurons.