Name: microvilli and cell surface area
Uploaded: 2023-06-23T15:38:44.000Z
Duration: 55 s
Channel: JoVE

Microvilli are thin, projections on the apical surface of epithelial cells that line specific organs, such as the small intestine, large intestine, and kidney.
These cells have a brush border appearance because of the finger-like protrusions.
Microvilli increase the plasma membrane&#39;s surface area twenty-five-fold, allowing for greater nutrient and water absorption. Additionally, enzymes present in the microvilli can aid in the break down of absorbed nutrients.&#160;&#160;
Actin microfilaments form the microvilli&#39;s internal structure. Villin and other bundling proteins like fimbrin crosslink actin and promote the formation of tightly bundled parallel arrays.
These bundles orient microvilli so they project outward from the apical cell surface.

microvilli

Microvilli

Microvilli are tiny finger-like projections found on the surface of certain cells. Their purpose is to increase the surface area of the cell&#39;s apical surface, resulting in more effective absorption or secretion of substances.
These microvilli are predominantly present in cells lining the small intestine, kidney tubules, and certain cells in the respiratory and reproductive systems. By significantly expanding the surface area of the cell membrane, microvilli enhance the cell&#39;s capacity to exchange materials with its surroundings.
Each microvillus is composed of a core of actin filaments that provide them with structural support. The actin filaments are connected to one another by other proteins, such as villin and fimbrin, giving the microvilli their characteristic shape. The cell membrane covering the microvilli contains various transport proteins and enzymes that assist in moving substances across the cell surface. The energy required for the transport processes is catered by the numerous mitochondria present at the basal ends of the cells.
In the small intestine, microvilli on the surface of epithelial cells significantly enhance the transport and absorption of nutrients from digested food. However, in individuals with celiac disease, an immune response to gluten damages microvilli, hampering nutrient absorption and resulting in malnutrition, cramping, and diarrhea.
In addition to their involvement in absorption and secretion, microvilli also play a part in sensory perception in some specialized cells. For instance, hair cells in the inner ear have microvilli which help to detect mechanical stimuli, convert them into electrical signals, and transmit them to the nervous system.
Overall, microvilli are vital structures that contribute to the functionality of various cells by increasing their surface area and enhancing their ability to interact with the surrounding environment.
This text is partially adapted from <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/">Openstax, Anatomy and Physiology 2e, Section 4.3: Eukaryotic cells</a>

Microvilli are tiny finger-like projections found on the surface of certain cells. Their purpose is to increase the surface area of the cell&#39;s apical ...

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Anatomy and Physiology

Unit 1

Cells and their Components

KEY TERMS AND CONCEPTS

microvilli and cell surface area

Microvilli are tiny finger-like projections on the surface of certain cells. They increase the surface area of the apical surface, which helps cells absorb or secrete substances more effectively. These structures are common in cells lining the small intestine, kidney tubules, and some cells in the respiratory and reproductive systems.

Each microvillus has a core made of actin filaments. Actin is a structural protein that helps support cell shape. Other proteins, including villin and fimbrin, connect the filaments and help give microvilli their shape. The membrane around the microvilli contains transport proteins and enzymes that move substances across the cell surface. Many mitochondria are found at the basal ends of these cells. They provide the energy needed for transport.

In the small intestine, microvilli play a major role in nutrient absorption from digested food. They help epithelial cells take up materials more efficiently because the larger surface area allows more exchange with the surroundings. In people with celiac disease, an immune response to gluten damages microvilli. This damage can reduce nutrient absorption and lead to malnutrition, cramping, and diarrhea.

Microvilli also have a sensory role in some specialized cells. In the inner ear, hair cells contain microvilli that help detect mechanical stimuli. These signals are converted into electrical signals and sent to the nervous system. Microvilli are therefore important for both movement of substances and sensory function in different cell types.

Microvilli and Cell Surface Area

what are cells?

Cells as the Basic Unit of Life

Cells are the basic unit of life. They are the smallest structures that make up living things, and they carry out the jobs needed to stay alive. Many organisms are made of one cell, while others are made of many cells working together. Cells share a few common features, but not all cells are the same. Some cells have a nucleus, which holds the genetic material, and other cells do not. Cells also differ in size, shape, and the specific work they do in an organism. Understanding cells helps...

cell diversity

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cytoplasm

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Nucleus Structure and Cell Control

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the nucleosome core particle

Histone Tails and DNA Packing

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chromatin packaging

How DNA Fits Inside the Nucleus

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the endoplasmic reticulum

Endoplasmic Reticulum: Cell Transport Network

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golgi apparatus

Golgi Apparatus in Cell Transport

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ribosomes

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the proteasome structure

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the proteasome

How Cells Remove Damaged Proteins

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introduction to cytoskeleton

Cytoskeleton: Cell Support and Movement

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Centrosomes in Cell Division

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microtubules in cell motility

Microtubules and Cell Movement

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mechanism of ciliary motion

How Cilia Create Movement

Cilia create movement by bending in a coordinated way. These tiny, hairlike structures help cells and fluids move in specific directions. The mechanism of ciliary motion explains how this repeated motion works. Cilia beat through a controlled motion that depends on their internal structure. Their movement is not random. It follows a set pattern that allows the cilia to push material across a surface or help a cell move. Understanding ciliary motion is important in cell biology. It shows how...

Microvilli are tiny finger-like projections on the surface of certain cells. They increase the surface area of the apical surface, which helps cells absorb or secrete substances more effectively. These structures are common in cells lining the small intestine, kidney tubules, and some cells in the respiratory and reproductive systems. Each microvillus has a core made of actin filaments. Actin is a structural protein that helps support cell shape. Other proteins, including villin and fimbrin,...

key terms and concepts

Learn how microvilli increase cell surface area, support absorption in the small intestine, and how damage from celiac disease can affect nutrient uptake.

Microvilli and Cell Surface Area | JoVE K12

anatomy and physiology

JoVE Core Anatomy and Physiology showcases the anatomical and physiological details of the human body in comprehensive, clear, and engaging video animations. This collection of lessons focuses on the structures, components, functions, and requirements of the human body. It is complemented by scientist-in-action videos that demonstrate the application of this knowledge in real-world medical and research settings.

Microvilli and Cell Surface Area

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