Types of Muscle Tissue: Skeletal | Smooth | Cardiac

Muscle and Muscle Fiber Structure:

A muscle is composed of many muscle fibers arranged in bundles called _______________________________
Individual muscles are separated by fascia, which also forms _______________________________

legsWhat is plantar fasciitis?


A muscle also contains 3 different layers of connective tissue:

__________________________ - outermost layer, surrounds entire muscle
__________________________ - separated and surrounds the FASCICLES (bundles)
__________________________ - surrounds each individual muscle fiber


Muscle Cells

The muscle fiber membrane is called the ___________________________________
The cytoplasm is called _______________________________________
Within the sarcoplasm are many parallel fibers known as ___________________________________

Each myofibril is made of many MYOFILAMENTS. There are two types:

MYOSIN - thick filaments
ACTIN - thin filaments

Structure of a SARCOMERE (functional unit of a muscle)

A Bands = dArk = thick = MYOSIN

I Bands = lIght = thin = ACTIN

Sarcomere = the area between two Z-lines

Heirarchy: Muscles → Fascicles (bundles) → Myofibrils → Myofilaments (actin & myosin)

II. How Muscles Work with the Nervous System

NEUROMUSCULAR JUNCTION (also called the motor unit) - where a ____________________and muscle fiber come together.

MOTOR END PLATE - specialized part of the sarcolemma located at the neuromuscular junction, has many folds

SYNAPTIC CLEFT - An actual "gap"which exists between the motor neuron endings and the motor end plate.

SYNAPTIC VESICLES - where _________________________ are stored before being released into the synaptic cleft.

The neurotransmitted that crosses the gap is __________________________________. This brings about muscle contractions.

CHOLINESTERASE is an enzyme that breaks down acetylcholine

III. The Sliding Filament Theory

The theory of how muscle contracts is the sliding filament theory. The contraction of a muscle occurs as the thin filament slide past the thick filaments.

What is needed: ACh = acetylcholine | AChE = acetylcholinosterase | Calcium | ATP | Actin & Myosin

*Handout on the Sliding Filament Model


Provided by ATP from cellular respiration which occurs in the___________________________

* Creatine Phosphate provides energy for the regeneration of ATP

* Only 25% of energy produced during cellular respiration is used in metabolic processes - the rest is in the form of HEAT - maintains body temperature

ATP = adenosine triphosphate | ADP = adenosine diphosphate


V: Other Terms

1. Threshold Stimulus

2. All-or-None Response

3. Motor Unit

4. Recruitment

5. Muscle Tone

6. Muscular Hypertrophy

7. Muscular Atrophy

8. Muscle Fatigue

9. Muscle Cramp

10. Oxygen Debt / Lactic Acid

11. Origin / Insertion