Important Facts About Body Anatomy

Human anatomy is the study of body structures and functions. You can gain an understanding of anatomy either through formal study at university with tutorials and cadaver dissection, or independent research.

Humans possess 206 bones which make up their skeleton. The stirrup bone is the smallest bone and found in the middle ear; red blood cells transport oxygen throughout their bodies via bone marrow production.


Bones form the structural backbone of your body, giving shape and helping you move. Living tissue, they undergo continual remodelling by your body in order to strengthen and harden over time. Bones protect vital organs as well as provide stores of minerals like calcium.

The human skeleton consists of bones, cartilage (pronounced ‘koh-luh-GLAH-shun”) and ligaments that connect bones together and muscles together. Ligaments connect bones together while cartilage acts like shock absorbers in joint throughout the body.

An adult body contains roughly 206 bones. Of these bones, the longest is called the femur in the leg and can measure 20 inches long.

Inside each bone in your body are holes known as bone marrow (meh-row), where new blood cells are produced and delivered throughout your system. Blood cells play an essential role in transporting oxygen throughout your body and helping clot blood if you get injured.

Your bones are typically covered by a hard, white coating known as the cortex that gives them their characteristic look. About 80% of bones feature this characteristic look while the remainder include spongy bone. Spongy bone looks similar to kitchen sponge with its porous structure but much harder surface area compared to compact bone; its pores are filled with osteoblast cells (pronounced ‘ah-steo-BLASTS) that build and repair bone structure.

Certain bones have growth plates, special zones of bones that expand as we get older. Other bones contain joints which allow our bodies to bend in many different ways – for instance knee joints allow backward, forward and sideward movement while skull boney plates may move slightly upon birth and then fuse as we grow older.


Blood is essential to life; it carries oxygen, nutrients and hormones throughout our bodies and forms blood clots to manage bleeding while protecting us against infections. Blood also serves as an early indicator of any possible health concerns, with abnormal blood tests often signaling that something may be amiss.

Blood is composed of plasma (the liquid part), formed cells and platelets. Plasma is a yellow, slightly cloudy fluid composed of water, salts, glucose, proteins and other substances and makes up 55% of total blood volume. Red and white blood cells (erythrocytes and leukocytes respectively) comprise formed cells while platelets act as tiny cell fragments which clump together in damaged blood vessels to stop flow of blood and prevent further loss.

Red blood cells are uniquely tailored to transporting oxygen. Their small size and flexibility enable them to pass through narrow blood vessels easily while their bi-concave shape maximizes gas diffusion surface area and contain millions of iron-containing haemoglobin molecules which bind oxygen molecule efficiently, before being sent on its journey toward lung capillaries for exchange of carbon dioxide before returning back to the heart and being circulated throughout the body again.

White blood cells make up one percent of total blood cells and play an essential role in fighting disease; there are five different kinds of these disease-fighting cells: eosinophils, basophils, lymphocytes and monocytes which all play different roles within our immune systems, such as recognising and eliminating bacteria, parasites, viruses or cancerous cells as well as helping regulate body temperature.


Organs are groups of tissues combining to form functional units with specific functions (your heart, kidneys and eyes are examples). Our bodies contain around 78 organs that work in concert to keep us alive; all serve an integral purpose to keep us functioning correctly as one system. There’s no one organ that’s more essential than another but keeping these essential ones healthy is key for human survival.

At the highest level of body organization lies organ systems. An organ is a collection of tissues joined together in an organized structure to perform specific functions; an example would be your digestive tract which includes epithelial cells lining its walls; muscle cells that transport food through it; and cells producing and secreting acids and enzymes in your intestines. When multiple organs work in harmony with one another they form systems or organ systems.

Organs include the skeletal, muscular, nervous, endocrine, respiratory and reproductive systems as organs; their structure and function is studied under human anatomy while how they interact with one another is known as physiology. Organ systems represent the highest level of organization within our bodies that are macroscopically visible such as brain, heart, lungs, liver and kidneys while reproductive tissues such as ovaries and testicles also play a vital role in producing estrogen that aids its regulation by the endocrine system.


Muscles are long, thin organs that contract to move bones. From helping us stand up straight or sitting up straight while eating to pumping blood around our bodies – muscles perform an invaluable service! There are three kinds of muscles: skeletal, smooth and cardiac; each perform their own important role within the muscular system (muskulo-SKEH-tuhl).

Skeletal muscles are under conscious control by your brain. They make up the muscles you can feel in your arms, legs and back. Muscle fascicles group these skeletal muscles together for ease of control by your mind; each fascicle contains protein filaments which slide over one another with energy provided from ATP molecules, creating contractions within individual cells which then causes contractions that help facilitate body movements both internal and externally. Muscle contractions account for movement throughout our bodies – both inside and out!

Smooth muscles cannot be controlled consciously; they’re found throughout your digestive tract, blood vessels and skin, expanding and contracting to let air in and out as you breathe. Cardiac muscle contracts and relaxes to move blood out from its chambers into circulation – an involuntary function.

Bones give your body its shape, protect internal organs from injury and enable movement. They’re also very strong – each bone’s centre contains bone marrow which produces new, healthy cells; most growth takes place between childhood and teenage years but spine or backbone remodelling happens constantly – this process often performed by skeletal muscles which attach themselves with tough fibers called tendons that connect bones together.

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