Posts Tagged ‘Anatomy’

A common cause of confusion in anatomy is the difference between cilia and villi.  Both of these are finger-like projections found in the body but they are found in different places and have entirely different jobs to do.

Cilia are tiny hair-like structures which are found on the surface of cells lining the upper-airways (the trachea and bronchi).  The job of the cilia is to WIGGLE!  The airways are coated with a thin layer of mucus which traps dust and particles stopping them from getting into the lungs.  The cilia wiggle to move the mucus up the airways toward the mouth so that it can be coughed up and swallowed.

Cilia

Villi are finger like structures found in the wall of the intestine [villus = one; villi = many].  Because they come out from the wall of the intestine, they have the effect of creating more space for absorption of nutrients; that is: they increase the surface area.  Villi are filled with blood vessels to take away the nutrients to the circulation.  They also contain a structure called a lacteal which absorbs fats from the intestine for delivery to the blood stream.

Villi

The surface area of the villus is increased even further by the presence of microvilli.  Microvilli are tiny structures on the surface of the villi.

NOTE: VILLI DO NOT WIGGLE – THEY DO NOT MOVE FOOD THROUGH THE INTESTINE.

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Kidney & Adrenal GlandCortex and Medulla are words which pop up all over the subject of anatomy.  The cortex is always the bit around the outside of a structure and the medulla is always the bit in the middle.

Examples include:

The Renal Cortex – the bit around the outside of the kidney
The Adrenal Cortex – the bit around the outside of the adrenal gland
The Cortex of bones (also known as Cortical Bone) – the thick dense bone tissue around the outside of bones
The Cerebral Cortex – the bit around the outside of the brain

Long Bone SectionThe Renal Medulla – the bit on the inside of the kidneys
The Adrenal Medulla – the bit on the inside of the adrenal gland
The Medulla of bones (also known as the medullary cavity) – the space in the middle of a long bone where the bone marrow is found

Use the similar sounds of the words MEDULLA and MIDDLE to help you remember!