Chapter 3 Organ Systems Overview

Overview of the organs system of the body. The cell is the basic unit or building block of all living things. According to their architecture and functions, cells are divided into four groups. Each of them is associated with one of the four tissue types: epithelial, muscular, nervous, or connective. A tissue is a collection of cells with similar structures and functions. An organ is a structure made up of two or more types of tissue that serves a specific purpose in the body. The small intestine, for example, is made up of all four tissue types and digests and absorbs nutrition.

An Overview of the Body’s Organ Systems

Organ SystemMajor component organsFunction
Epidermal and dermal regions;
cutaneous sense organs and glands
• Prevents deeper organs from being damaged by mechanical, chemical, and bacterial agents, as well as drying up.
• Excretes urea and salts
• Assists in body temperature regulation
• Generates vitamin D
Skeletal Bones, cartilages, tendons, ligaments,
and joints
• Body support and internal organ protection
• Provides muscular action levers
• Cavities serve as a place for blood cells to develop.
MuscularMuscles attached to the skeleton• Skeletal muscles’ primary role is to contract or shorten, allowing movement (running, walking, etc. ), gripping and manipulating the surroundings, and facial expression.
• Produces heat
NervousBrain, spinal cord, nerves, and sensory receptors• Enables the body to notice changes in its internal and external environment and respond by activating the appropriate muscles or glands.
• Helps the body maintain homeostasis by transmitting electrical signals quickly.
Endocrine Pituitary, thymus, thyroid, parathyroid, adrenal, and pineal glands; ovaries, testes, and pancreas• Contributes to bodily homeostasis, growth, and development; generates chemical messengers known as hormones that flow via the bloodstream to exert their effect(s) on various body organs.
CardiovascularHeart, blood vessels, and blood• Blood is primarily a transportation system that transports oxygen, carbon dioxide, nutrients, wastes, ions, hormones, and other substances to and from tissue cells where exchanges occur; blood is propelled through the blood vessels by the heart’s pumping action
• Antibodies and other protein molecules in the blood protect the body.
Lymphatic vessels, lymph nodes, spleen, thymus, tonsils, and scattered collections of lymphoid tissue• Collects fluid that has leaked from blood vessels and restores it to the bloodstream.
• Removes germs and other debris from the blood
• Lymphocytes are immune system cells that protect the body from invading chemicals.
RespiratoryNasal passages, pharynx, larynx,
trachea, bronchi, and lungs
• Provides constant oxygen to the circulation while eliminating carbon dioxide.
• Through its carbonic acid–bicarbonate buffer system, it contributes to the blood’s acid-base equilibrium.
DigestiveOral cavity, esophagus, stomach, small and large intestines, and accessory
structures including teeth, salivary glands, liver, and pancreas
• Degrades eaten nutrients into minute particles that can be taken into the bloodstream and delivered to body cells.
• Undigested waste is excreted in the form of feces.
KidneyKidneys, ureters, bladder, and urethra• Removes nitrogen-containing wastes from the body, such as urea, uric acid, and ammonia, which are produced by the breakdown of proteins and nucleic acids.
• Keeps the blood’s water, electrolyte, and acid-base balance in check.
ReproductiveMale: testes, prostate gland, scrotum, penis, and duct system, which carries
sperm to the body exterior
Female: ovaries, uterine tubes, uterus, mammary glands, and vagina
• Provides sperm, or germ cells, for the species’ perpetuation.

• Produces germ cells known as eggs; the female uterus homes the developing fetus till birth; mammary glands nourish the child

An organ system is a collection of organs that work together to carry out a certain physiological function. The digestive system’s organs, for example, collaborate to break down foods and absorb the end products into the bloodstream, supplying nutrients and fuel to all of the body’s cells. There are 11 organ systems in total. The immune system, which is made up of an army of mobile cells that acts to protect the body from invading chemicals, is also included in the lymphatic system.

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