THE MUSCULAR SYSTEM

Introduction

Our bodies have over 600 muscles, which make up half of our body weight

Muscles are used to eat, talk, walk etc

Muscles burn lots of calories when they are being used and when resting

Muscles burn even more calories when they are “in shape”

MAJOR MUSCLE TYPES

SMOOTH MUSCLE:

Involuntary and contract

automatically

CNS adjusts contraction as required

They do not tire easily and can stay

contracted for long periods of time

Ex. Esophagus, stomach, blood vessels

MAJOR MUSCLE TYPES

CARDIAC MUSCLE

Specialized muscle tissue that

comprises the heart

Involuntary

MAJOR MUSCLE TYPES

SKELETAL MUSCLES:

Connect to bones by tendons

Voluntary – you control them

The engines that pull on bones –

causing joints to move

MUSCLE DESCRIPTION PRIMARY ROLE

Deltoid - forms rounded contour of shoulder

- shoulder abduction, flexion and extension 

Biceps Brachii

-“bicep” muscle

-Flexion of elbow-Rotation of forearm 

Brachialis -muscle in the upper arm

Flexion of elbow 

Pectoralis Major

- “chest” muscles

- adducts and medially rotates arm

External Obliques

- largest, most superficial of “ab” muscles 

- rotates torso 

Rectus Abdominus

“ 6 pack” / “washboard” abs

- flexion of trunk

MUSCLE DESCRIPTION PRIMARY ROLE

MUSCLE DESCRIPTION PRIMARY ROLE

Sartorius -long thin muscle runs down the length of thigh-longest muscle in the body 

Flexion of knee / leg

Rectus Femoris

- 1 of 4 leg (quad) muscles 

- knee extension- hip flexion

Vastus Intermediums

- under rectus femoris

- extends leg 

Vastus Laterailis

- largest part of leg muscles

- extends and stabilizes knee 

Vastus Medialis

- “tear drop” muscle- medial (inner) leg muscle 

- extends leg

Tibialis Anterior

- shin - dorsiflexion of the foot (toes up) 

Rhomboids - Diamond shape-Deep to trapezius 

-holds scapula to ribcage-retracts scapula 

Trapezius - “shoulder blade”

  

MUSCLE DESCRIPTION PRIMARY ROLE

MUSCLE DESCRIPTION PRIMARY ROLETriceps Brachii - “tricep” muscle

 - extension of elbow / forearm- adducts shoulder 

Latissimus Dorsi

“V” - adducts, extends and internally rotates arm

Gluteus Medius

- above maximus 

- abduction of the hip- medial rotation of thigh 

Gluteus Maximus

- largest “bum” muscle- makes up shape and appearance

- external rotation and extension of the hip joint  

MUSCLES IN ACTION…

Muscles work through a process called contraction.

Muscle Contraction – result of filaments deep within the muscle sliding over each other

This process occurs simultaneously over entire muscle fibre – resulting in contraction

SLIDING FILAMENT THEORY

Sequence for contraction:1. Electrical impulse comes from brain

(voluntary) or spinal cord (involuntary)

2. Signal travels along nerve to muscle site (neuromuscular junction) and attempts to jump the gap.

SLIDING FILAMENT THEORY

3. Chemical reaction takes place deep within the muscle fibre

4. The reaction causes the filaments to “slide” over one another. Thin filament (actin) slide past the thick filament (myosin)

5. Muscle fibre contracts.

http://www.youtube.com/watch?v=EdHzKYDxrKc

Types of Muscle Contraction CONCENTRIC – muscle shortens

while working

ECCENTRIC – muscle lengthens while working

ISOMETRIC – no change in length. Force = resistance.

ANATOMY DIAGRAM

Complete the chart and diagram

Instructions Now that you’ve taken a look at the muscular system, you will take a quick look at the path of blood in our system. We discussed this briefly yesterday, but you will need the following information for a unit test.

Mr. Ceccarelli

PATH OF BLOOD

Pulmonary Circulation Systemic Circulation

Veins and Arteries

Veins transport blood TO the heart

Arteries transport blood AWAY from the heart

Pulmonary Circulation

circulation of blood between the heart and the lungs

Deoxygenated blood (blue) becomes oxygenated (red)

Path of Deoxygenated Blood

Right Atrium (upper chamber)

Tricuspid Valve

Right Ventricle (lower chamber)

Path of Deoxygenated Blood

Pulmonary Valve

Pulmonary Artery

Lungs carbon dioxide is released, Oxygen is picked up

Systemic Circulation

circulation of blood between the heart and the body

From the lungs Oxygenated blood returns to the heart through the Pulmonary Veins

Path of Oxygenated Blood

Mitral Valve

Left Ventricle (lower chamber)

Path of Oxygenated Blood

Aortic Valve

Aorta – major artery that supplies blood to entire body

Body

Instructions For the grand finale……

Lactic Acid???

Read p 49 and describe Lactic acid and how it forms and discuss how it affects the body.

This may make a great test question…..

Final Note: This now concludes our programming for

today – thanks for watching!!!

Remember to get your rock climbing form and money in for Monday AND to bring in money for St. Michael feast day next Thursday.

You can now put down your pencils and take a deep breathe – health is over…… for now….. Have a great weekend.

Mr. C!