CGTC FAQs: Academic Support

Muscles are a fundamental component of the human body, playing a vital role in nearly every bodily function.  There are three different types of muscle tissue, each with specialized functions:  skeletal, smooth, and cardiac.  Below are the key functions of muscle in anatomy and physiology.  

1.  Movement

• Skeletal muscle:  Skeletal muscles are attached to bones via tendons and contract to pull on the bones, causing movement at joints.  This includes all voluntary movements like walking, running, lifting, speaking, and facial expressions.  
• Smooth muscle:  Found in the walls of internal organs and blood vessels.  Smooth muscle contracts involuntarily to move substances through the body.  Examples include:
  • Peristalsis where wavelike contractions in the digestive tract to move food.
  • Blood Pressure Regulation--contraction and relaxation of smooth muscle in blood vessel walls regulate blood flow and pressure.
  • Urination--contraction of smooth muscle in the bladder wall helps expel urine.  
  • Childbirth--uterine smooth muscle contracts to push the baby during labor.   
• Cardiac muscle:  This specialized muscle tissue makes up the walls of the heart.  Its rhythmic and involuntary contractions are responsible for pumping blood throughout the circulatory system. 

2. Maintaining posture and position:

• Skeletal muscle:  Even when you're standing or sitting still, your skeletal muscles are continuously making small adjustments to maintain your body's posture and keep you upright against gravity.  

3.  Heat production (thermogenesis)

• All muscle types primarily skeletal muscle contraction is a metabolic process that generates heat as a byproduct.  This heat is crucial for maintaining a stable body temperature.  When you're cold, your muscles shiver involuntarily to generate more heat.  

 4.  Stabilizing joints:

• Skeletal muscle and their tendons that cross over joints contribute significantly to joint stability.  They help to prevent excessive movement or dislocation.  

5.  Storage and metabolism

• Skeletal muscle serves as a significant storage site for essential substrates like carbohydrates (as glycogen) and amino acids.  It also plays a role in basal energy metabolism

6.  Protection

• Skeletal muscles, particularly the muscles of the body wall, help to cushion and protect internal organs from external forces.  

7.  Respiration

• Skeletal muscles (diaphragm and intercostals) are essential for breathing, controlling the expansion and contraction of the thoracic cavity.

8.  Vision

• Skeletal muscles:  Six extrinsic eye muscles control the movement of your eyeballs.  
• Smooth muscle:  Intrinsic eye muscles (ciliary muscle and iris) regulate the shape of the lens and pupil size, respectively, for focusing vision.

In conclusion, muscles are highly adaptable tissues that enable a vast array of physiological processes.  From conscious movement and maintaining posture to involuntary functions like blood circulation and digestion, they all contribute to the overall homeostasis and functioning of the human body.