Types of muscle and functional characteristics of muscle. Levels of organization of muscle, fascicles, myofibrils, and myofibers. Microanatomy and functional unit of contraction, the sarcomere. Used as basis for lecture to high school science students

1. Muscle Tissue 1
Muscle types and functional characteristics
Levels of organization and microanatomy of muscle

2. The basics
Muscles are attached to bones
Muscles contract (get shorter) and move bones
Muscles comprise 40-50% of body mass
Myology
Study of muscle anatomy and physiology
Myo- Mys- Sarco- = prefixes that reference muscle

3. Muscle functional characteristics
Excitable / excitability
ability to respond to stimuli
Contractile / -ility
ability to shorten; initiated by nerve signal (action potential)
Extensible / -ility
ability to stretch; lengthen
Elastic / -icity
ability to return to original length

4. Types of muscle
Skeletal
Attached to bones, striated, voluntary
Cardiac
Forms heart, striated, involuntary
Smooth
Walls of blood vessels, stomach intestines, hair follicles, nonstriated, involuntary

5. Muscle Functions
Motion
contraction moves bones; body
blood flow
peristalsis (squeezing of intestines)
gall and urinary bladder contraction
Posture maintenance / joint stabilization
Thermoregulation
contraction results in heat energy release

9. Skeletal muscle contraction
(microanatomical TEM)

13. Skeletal muscle tissue organization

15. Connections
Tendons
Dense connective tissue continuous with deep
fascia, connect muscles to periosteum
Aponeuroses
Broad flat tendon attachment to bone, or to
different muscle, or skin

20. Microanatomy

27. Muscle Contraction Requirements
Nerve impulse
A nerve penetrates every muscle
Synaptic bulb / neuromuscular junction = muscle
connection with nerve cell
Blood
Supplies energy, nutrients, oxygen
Removal of waste and heat
Each muscle fiber is in contact with capillaries