- The cell is the basic structural, functional, and biological unit of all known organisms.
- A cell is the smallest unit of life. Cells are often called the “building blocks of life”.
- The study of cells is called cell biology, cellular biology, or cytology.
- Cells provide six main functions.
- They provide structure and support, facilitate growth through mitosis, allow passive and active transport, produce energy, create metabolic reactions and aid in reproduction.
- The term tissue is used to describe a group of cells found together in the body.
- The cells within a tissue share a common embryonic origin.
Although there are many types of cells in the human body, they are organized into four broad categories of tissues: epithelial, connective, muscle, and nervous.
- There are 4 basic types of tissue: connective tissue, epithelial tissue, muscle tissue, and nervous tissue.
- Connective tissue supports other tissues and binds them together (bone, blood, and lymph tissues).
- Epithelial tissue provides a covering (skin, the linings of the various passages inside the body)
- Cartilage is an avascular, flexible connective tissue located throughout the body that provides support and cushioning for adjacent tissues.
- Cartilage is a flexible connective tissue that keeps joint motion fluid by coating the surfaces of the bones in our joints and by cushioning bones against impact.
- It is not as rigid as bone, but is stiffer and less flexible than muscle tissue.
- There are three types of cartilage:
- Hyaline – most common, found in the ribs, nose, larynx, trachea. Is a precursor of bone.
- Fibro- is found in intervertebral discs, joint capsules, ligaments.
- Elastic – is found in the external ear, epiglottis and larynx.
- A bone is a rigid organ that constitutes part of the vertebrate skeleton in animals.
- Bones protect the various organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, and enable mobility.
- The conventional function of the skeleton is as a static structural organ supporting body movement, protecting the internal organs, and as a reservoir of minerals.
- Cellular components:
- Osteoblasts (bone forming cells),
- osteocytes (inactive osteoblasts),
- osteoclasts (cells that reabsorb the bone).
- The 7 functions of bone:
- Support: Bones provide a framework that supports the body and cradles its soft organs.
- Protection :The fused bones of the skill protect the brain.
- Mineral and Growth factor storage.
- Blood Cell Formation.
- Triglyceride (Fat) storage.
- Hormone production.
Define Muscular Tissue:
- Muscle tissue consists of elongated cells also called as muscle fibers. This tissue is responsible for movements in our body.
- Muscles contain special proteins called contractile protein which contract and relax to cause movement.
- Muscle tissues vary with function and location in the body.
- Each of these muscles is a discrete organ constructed of skeletal muscle tissue, blood vessels, tendons, and nerves.
- Muscle tissue is also found inside of the heart, digestive organs, and blood vessels.
- In these organs, muscles serve to move substances throughout the body.
- Types of Muscle Tissue:
- Skeletal Muscle Tissue
- Cardiac Muscle Tissue
- Smooth Muscle Tissue.
Define Nervous Tissue:
- Nervous tissue is found in the brain, spinal cord, and nerves.
- It is responsible for coordinating and controlling many body activities.
- The cells in nervous tissue that generate and conduct impulses are called neurons or nerve cells.
- These cells have three principal parts: the dendrites, the cell body, and one axon.
- Nervous tissue contains two categories of cells — neurons and neuroglia.
- The outside layer of cells that covers all the free, open surfaces of the body including the skin, and mucous membranes that communicate with the outside of the body.
- Layer of cells closely bound to one another to form continuous sheets covering surfaces that may come into contact with foreign substances.
- By contrast the endothelium is the layer of cells lining the closed internal spaces of the body such as the blood vessels and lymphatic vessels.
- Epithelium may be protective, absorptive, or secretory.
- It may produce special outgrowths (hairs, nails, horns on animals), and manufacture chemical material (e.g., keratin).
- Skin is the largest organ in the body and covers the body’s entire external surface.
- It is made up of three layers, the epidermis, dermis, and the hypodermis, all three of which vary significantly in their anatomy and function.
- The skin’s structure is made up of an intricate network which serves as the body’s initial barrier against pathogens, UV light, and chemicals, and mechanical injury.
- The skin is primarily made up of three layers.
- The upper layer is the epidermis, the layer below the epidermis is the dermis, and the third and deepest layer is the subcutaneous tissue.
- The epidermis, the outermost layer of skin, provides a waterproof barrier and contributes to skin tone.
- The bottom or deepest layer of the skin is Hypodermis.
- Histology is the science of the microscopic structure of cells, tissues and organs.
- It also helps us understand the relationship between structure and function.
- Microanatomy or microscopic anatomy, The study of cells and tissues, from their intracellular components to their organization into organs and organ systems.
CATHERINE SHALINI RAJA
CARDIO RESPIRATORY PHYSICAL THERAPIST
FITNESS & SPORTS REHABILITATION SPECIALIST.