04.02 Muscle Anatomy

Overview

1. Types of muscle
   1. Skeletal (somatic)
      1. Voluntary
      2. Innervation
         1. CNS → Somatic nervous system
         2. 1 nerve cell to 1 muscle cell
            1. Myoneural junction
            2. Neuromuscular junction
   2. Cardiac
      1. Involuntary
      2. Innervation
         1. CNS → Autonomic nervous system
         2. 1 nerve cell to  several cardiac muscle cells
   3. Smooth (visceral)
      1. Involuntary
      2. Innervation
         1. CNS → Autonomic nervous system
         2. 1 nerve cell to 1 muscle cell
            1. Fast contracting muscles
            2. Intrinsic eye movements
         3. 1 nerve cell to several muscle cells
            1. Gross movements
            2. Intestines, ureters in excretory system

Nursing Points

General

1. Locations
   1. Skeletal
      1. Associated with bones
      2. Surrounds some cavities
         1. Buccal
         2. Abdominopelvic
         3. Thoracic
      3. Diaphragm
      4. Bulk of extremities & tongue
      5. Extrinsic eye muscles
   2. Cardiac muscle → in heart
   3. Smooth muscle
      1. Walls of hollow organs
         1. Blood vessels
         2. Digestive tract
         3. Respiratory tract
         4. Excretory tract
         5. Reproductive
      2. Capsule of spleen
      3. Intrinsic muscles of the eye
2. General functions of muscle
   1. Movement/propulsion
      1. Skeletal muscle
         1. Locomotion
         2. Grasping
         3. Movement of head
         4. Breathing movements
         5. Eye movement
      2. Cardiac muscle
         1. Propels blood through the cardiovascular system
      3. Smooth muscle
         1. GI tract → move food
         2. Urinary tract → move urine to bladder
            1. Peristalsis
         3. Micturition (urination)
            1. Bladder
         4. Parturition (childbirth)
            1. Uterus
         5. Defecation
            1. Rectum
   2. Regulation of blood pressure
      1. Smooth muscle contraction in arterioles
         1. Vasoconstriction
         2. Vasodilation
   3. Posture
      1. Skeletal muscle
      2. Muscle tonus—keeps muscles mildly contracted
         1. Spinal cord sends nerve impulses
         2. Neck
         3. Trunk
         4. Legs when standing
   4. Body heat production
      1. All muscles break down glucose
         1. Byproduct = heat
      2. Skeletal muscle
         1. Contraction → heat
         2. 40% of body mass