1. The Muscular System
An Overview of Unit 7

2. Muscles
Composed of over 600 organs
Each muscle is an individual organ

3. Muscle Types 3 types Differ in Skeletal Cardiac Smooth Cell structure
Body location
How they are stimulated to contract

4. Let’s make a table! Characteristic Skeletal Cardiac Smooth
Body location
Cell appearance and shape
Regulation of contraction

5. Body Location Skeletal Cardiac Smooth
Attached to bones or skin (in the case of facial muscles)
Cardiac
Walls of the heart
Smooth
Mostly in the walls of hollow organs, with the heart as the exception
Small intestine, stomach, esophagus, blood vessels, uterus

6. Cell Shape and Appearance
Skeletal
Single, very long, cylindrical, and multinucleated cells
Striations
What does that mean?
Striped

7. Cell Shape and Appearance
Cardiac
Branching chains of cells
Gap junctions
“intercalated disks”
What do those look like?
Uninucleated
Striations

8. Cell Shape and Appearance
Smooth
Single
Uninucleated
No striations
“fusiform”
Like a seal

9. Voluntary vs Involuntary
What does that mean?

10. Regulation of Contraction
Skeletal
Voluntary
Cardiac
Involuntary
Smooth
involuntary

11. Functions Produces movement Skeletal Smooth Cardiac Movement of limbs
foodstuff, a baby
Cardiac
Blood

12. Functions Maintain posture Allows us to be upright
Question: Which muscle type mostly does this function?
Skeletal

13. Functions
Stabilizing joints
Allow for controlled movements

15. Functions Generating heat Question: Why do we shiver?
By-product of muscular activity
Question: Why do we shiver?
When our body senses that we are decreasing in body temperature, a signal is sent to our skeletal muscles
They begin to rapidly contract and relax
This is muscular activity so heat is generated!

16. Worksheet #1!