How skeletal and smooth muscles differ

What is the muscular system?

The muscular system comprises three distinct types of muscle: smooth, cardiac, and skeletal. Cardiac muscles make up the heart, whereas smooth and skeletal muscles are found throughout the body. Smooth muscles line blood vessels and most organs, and skeletal muscles are responsible for moving the body or holding it stationary. All muscles are made of muscle cells or fibers, which give them the ability to contract.

Muscular system explained

Skeletal, cardiac, and smooth muscles form the system that powers movement, survival, and daily life. Skeletal muscles are voluntary, enabling conscious actions like lifting or walking, while cardiac and smooth muscles are involuntary, controlled by the autonomic nervous system. From every heartbeat to each breath, these three muscle types work in harmony to keep you moving, thriving, and alive.

What does the muscular system do?

The muscular system is responsible for movement by and throughout the body. Smooth muscle contractions push food and blood through the digestive tract and blood vessels, respectively. Skeletal muscles are responsible for voluntary movement or lack thereof by the body. Cardiac muscle controls the beating of the heart, which is the pump that powers the circulatory system responsible for distributing energy and nutrients to cells across the body.

One of the leading theories behind muscle movement

According to the Sliding Filament Theory, skeletal muscle contraction is made possible by sarcomeres, which are made of bundles of myosin and actin proteins inside muscle cells. Myosin pulls itself along actin to contract a muscle, shortening the muscle and its cells and enabling physical movement. It then releases its grasp on actin so it can start the process over again if so commanded.

Explore the abundance of different types of cells in the human body

Lacking a nucleus and other organelles to maximize space for oxygen-carrying hemoglobin and enhance maneuverability through narrow capillaries, there are about four times as many red blood cells and platelets as all other cell types in the body combined. However, about half of the body's cell biomass consists of skeletal myocytes, or muscle fibers.

How does food move through the body?

Food passes through the digestive system via muscle movement known as peristalsis, during which a rippling contraction slowly pushes content through tubular organs, such as the esophagus and intestines. This is similar to what happens when one squeezes a tube of toothpaste, contracting the tube behind the content and forcing the tube in front of the content to expand, allowing the content to move forward.

What is the peripheral nervous system?

This nervous system extends throughout the body, where it acts as the informational bridge between the central nervous system, housed in the brain and spinal cord, and the body's muscles and organs. The peripheral nervous system is further divided into the autonomic, enteric, and somatic nervous systems, each of which oversees certain muscle types and processes. This article overviews the anatomy and functions of the peripheral nervous system.

How muscles get their names

There are more than 600 muscles that crisscross the human body, and each has a name that's more than a simple label. Muscle names also typically communicate the muscle's size, behavior, length, location, appearance, direction, and attachments to bone. These names usually have Greek or Latin roots, such as in the case of the deltoid muscles, which are named in reference to the Greek letter delta (𐤃).

Snakes move around by coordinating hundreds of muscles

These muscles connect to their vertebrae, and allow the creature to move in various unique ways. Snakes can slither, move in a straight line, swim, jump and even "fly."

Physiological muscle memory allows us to quickly regain lost musculature

The term "muscle memory" is most often associated with the neurological kind, which involves the development of strong and efficient neural pathways in the brain and spine. Physiological muscle memory also slows the loss of muscle mass, with both types affected by genetics and diet.

How humans breathe without thinking about it

We breathe without thinking about it thanks to the body’s respiratory system and autonomic nervous system, which controls vital functions. Breathing transports oxygen to the body’s cells to keep them working and clears the body of carbon...

The difference between embryonic and adult stem cells

The main difference between embryonic and adult stem cells lies in their potential and origin. The former can become any cell type in the body, while the latter are limited to specific cell types. Embryonic stem cells also carry ethical concerns when used in medical or clinical applications.

'Viscoelasticity' allows muscles to be elongated briefly after stretching

The protective tissues around skeletal muscles consist of elastic proteins like collagen. Stretching them expands their length while retaining strength, ideal for athletes.

Laminar flow moves in smooth, parallel layers, while turbulent flow is chaotic

In laminar flow, particles that make up a fluid move in consistent paths that do not cross each other. Contrastingly, differences across the speed of these particles cause them to mix, creating turbulence when viscosity cannot suppress the differences.

Why yoga teachers are dissecting cadavers

Thousands of fitness professionals are choosing to attend cadaver workshops to improve their understanding of anatomy and their teaching abilities. Though 3D virtual models give students a fresh way to explore the human body, medical students say experiencing the intricacies in person is far more instructive. As fitness professionals increase their understanding of the muscular and skeletal systems, their movement cues and instructions evolve in tandem.

Taste buds are found throughout the body, with different biological functions

As biological structures, taste receptors take in molecules, analyze them, and send signals to the brain letting us know what they've found. This functionality makes them useful throughout the body, most notably in the gut where receptors act as glucose sensors.

The neuroscience of REM atonia disorders, where patients act out dreams

What prevents the typical person from acting out their dreams? Temporary paralysis of skeletal muscles, usually leading up to, and during, REM sleep. This academic article and related graphics explore what happens when this process doesn't go as planned, leading to REM sleep behavior disorder.

Operas rely more on music for storytelling than musicals

It’s easy to confuse operas and musicals since they both tell stories through singing and music—but a few key differences remain. While musicals rely on words as the primary tool for storytelling, opera relies more on music. Other key distinctions lie in vocal techniques.

The anatomy of our hair follicles explains goose bumps

The arrector pili muscle contracts when we’re cold or scared, causing hairs to stand up and the skin to form the bumps known as goose bumps. This reaction is typically involuntary.

Similarities between human and animal sleep

Have you ever noticed the wide-ranging differences in sleep between humans and animals? Sleep as a necessity is present amongst all animal species, but the specific patterns of sleep vary widely. Just think of the differences between how an owl, a whale, and a horse might sleep. This helpful resource from the Sleep Foundation explores the relations between human and animal sleep, complete with some fascinating statistics about sleep patterns throughout the animal kingdom!

Sclerosis is the technical term for the lesions or plaques that form without myelin

In the absence of myelin, the body forms scar tissue called sclerosis. That scar tissue hampers nerve's abilities to transmit nerve impulses, essentially acting as a roadblock to speedy communication.

Anatomy of a healthy knee joint

To understand arthritis, study a normal joint. Where two bones come together, each is lined by a cartilage cap. These bones are linked together by strong ligaments. The inner juncture is lined by a joint capsule (synovial membrane) containing lubricating joint fluid between the two surfaces, allowing for near-frictionless motion.

The four types of seismic waves are categorized as body or surface waves

Primary (P) and secondary (S) waves are compression and shear waves, respectively, and travel through Earth’s interior, though secondary waves only move through solids. These waves’ energy is converted into rolling Rayleigh or horizontal Love waves at the surface.

Vertigo is a mismatch of information between the eyes and the ears

Both vertigo and motion sickness can be caused by mismatches between visual and auditory inputs.The brain relies on inputs from the eyes, inner ear, and receptors in muscles and joints to orient the body. When the eyes suggest movement but other signals suggest the body is stationary dizziness and nausea can occur.

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

How mutual funds work

Mutual funds function similarly to other types of investments. If you want to invest, you go through a brokerage firm. However, they have a few key differentiators. Most are actively managed by a broker instead of passively earning you returns. Plus, they can carry some hefty fees.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

The United States is one of only around two dozen countries with a fully federal system of government, in which power is divided between national and state governments.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Corals are themselves not coral reefs—the term refers to the tiny marine invertebrates that build the rigid reef.

Ebola is a filovirus, meaning it resembles a thread under a microscope, though it sometimes twists and can resemble a bowl of spaghetti.

Browse a detailed visual analysis of over 200,000 similes—comparisons that often use 'like' or 'as'—from popular fiction to see how frequently writers the same idiomatic expressions.

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

Explore chaos in this simulation of two double pendulums, where small differences in the release angles produce wildly different outcomes.

The animatronic shark from Steven Spielberg's 'Jaws,' the first modern blockbuster, was a complex underwater apparatus called 'Bruce.'

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Lesser-known phobias include turophobia, or the fear of cheese, and nomophobia, the fear of being without your cell phone.

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.

Sony set the standard for cylinder-shaped batteries when it repurposed manufacturing equipment used to make rolls of magnetic recording tape.

Play the role of a student in a game where you try to navigate college and remain debt-free, selecting different income levels, high school experience, race, ethnicity, and more.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.