Muscular System

Question 1

What are the functions of muscle System? List at least 5 and give short descriptions.

Answer 1

1. Movement - enable movements by contracting and pulling on bones
2. Posture Maintenance - maintain posture and balance by holding the body in stable position
3. Heat Generation - Muscle activity generates heat and helps maintain normal body temperature (thermoregulation)
4. Joint Stabilization - support soft tissues (joints)
5. Protection - protect internal organs by forming muscular wall (e.g. abdominal wall)

(6. Breathing/ Circulation / Digestion: by smooth and cardiac muscle

e.g.
- Pumping blood (Heart)
- Peristalsis; helping moving food through digestive tract )

Question 2

List 3 types of muscle tissues and give descriptions.

Answer 2

1. Skeletal Muscle
   * Voluntary striated and multi-nucleated muscle usually found in the limbs and attaches to skeleton
   
   • allow conscious movement controlled by CNS (and PNS while sleeping)
   • contract quickly, tire easily, and work in coordinated groups to generate body movements
2. Cardiac Muscle
   * Involuntary, striated and uni-nucleated muscle found only in the Heart
   
   • contracts rhythmically to pump blood
   • has built-in pace-making ability (myogenic) and is regulated by PNS (Autonomic NS) to adjust heat rate as needed
3. Smooth Muscle
   * Involuntary, non-striated and uni-nucleated muscle found in the walls of internal organs (Stomach, blood vessels).
   
   • Automatically under the control of PNS (ANS) to regulate processes such as digestion and circulation without conscious efforts

Question 3

List 5 properties of muscles and also give short descriptions.

Answer 3

1. Excitability - the ability to receive and respond to stimuli (neurotransmitter, hormones, pH change); respond by generation and transmission of action potential
   
   • skeletal muscle : respond quickly, with force contraction
   • Visceral muscle : respond slowly, maintaining contraction over a longer periodic time
   • cardiac muscle : respond quicker than smooth muscle, contract stronger (but longer duration)
2. Contractility - ability to shorten forcibly
3. Extensibility - ability to be stretched
4. Elasticity - ability to resume resting length (after being stretched)
5. Automaticity - ability to contract without nerve impulse