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

MUSCLEDESCRIPTIONPRIMARY 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 MUSCLEDESCRIPTIONPRIMARY ROLE

MUSCLEDESCRIPTIONPRIMARY 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” MUSCLEDESCRIPTIONPRIMARY ROLE

MUSCLEDESCRIPTIONPRIMARY ROLE Triceps 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.

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

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 ValvePulmonary 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 Left Atrium (upper chamber) 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!