The Muscular System

1. The Muscular System Fiona Adams and Harsha Kumar

2. What is It? • The system of the body that is composed of three main muscle types: skeletal, smooth, andcardiac muscle tissue • Function: movement of the body/movement of materials through the body; maintenance of posture and heat production

3. Muscles • Muscles are arranged in layers over the bones. • Superficial muscles: Those nearest to the skin • Deep Muscles: Those closest to the inside of the body DeepMuscles Superficial Muscles

4. What is Skeletal Muscle? • Helps in movement and supports the skeleton. • provides extension and contraction movements to the limbs, provides strength and support for the body, protects internal organs • They link two bones across its connecting joint-When these muscles contract or shorten, the bone moves • They are voluntary muscles, muscles that can be consciously controlled

5. Two Types of Skeletal Muscles • Red: consists of a chemical called myoglobin (a protein-like molecule which aids in the storage of oxygen). This allows these types of muscle to maintain a higher level of activity for a longer period of time because the myoglobin provides an extra reserve of oxygen. • White: muscle that doesn’t contain myoglobin. The lack of myoglobin doesn’t allow the muscle to maintain a high level of activity for very long

7. Examples of Skeletal Muscles • Gluteus Maximus- buttocks • Abdominal muscle- abdomen/stomach • Pectorals- chest • Quadriceps- triceps/biceps/extensors/flexors

8. Abdominal GluteusMaximus Quadriceps Pectoral

9. What is Smooth Muscle? • Controls slow, involuntary movements such as the contraction of the smooth muscle tissue in the walls of the stomach and intestine; it’s the muscle in the arteries that contracts and relaxes to regulate blood pressure/blood flow • They are involuntary movement muscles cannot be controlled • not connected to bones • made up of thin-elongated muscle cells, fibers which interlace to form sheets of muscle tissue

10. Examples of Smooth Muscles • forms the muscle layers in the walls of hollow organs • digestive tract (lower part of the esophagus, stomach and intestines) • walls of bladder, uterus, various ducts of glands, walls of blood vessels .

11. What is Cardiac Muscle? • Its the specialized striated muscle tissue of the heart also known as the myocardium. • found solely in the walls of the heart • The contractions are not under conscious control (involuntary) • It is highly resistant to fatigue due to the presence of a large number of mitochondria, myoglobin and a good blood supply allowing continuous aerobic metabolism • Function: Pump blood

13. Muscular SystemDisorders

14. Orofacial Myology Disorders • disorders that affect the muscles surrounding the face, jaw, lips and mouth • types include: of blocked nasal airways, dental malocclusions, speech problems, atypical swallowing and chewing patterns, abnormal posture of the orofacial musculature while resting

15. Atony • muscles lose their elasticity • Causes :atonic seizures (alterations caused in the brain for a temporary period of time) • uterine atony (uterus muscles cannot contract and hemorrahage occurs) • gastrointestinal atony (muscles lose their propulsive ability and activity in gastrointestinal tract is affected)

16. Myopathy • characterized by muscle weakness which results from improper functioning of muscle fibers • stiffness, muscle cramps and spasms occur

17. Cardiomyopathy • Muscular Dystrophy that affects the cardiac muscle • Causes disturbed heart rhythm (arrhythmias)

18. Muscular Dystrophy • Mental retardation (only present in some types of the condition) • Muscle weakness that slowly gets worse • Delayed development of muscle motor skills • Difficulty using one or more muscle groups • Drooling • Eyelid drooping • Frequent falls • Loss of strength in a muscle or group of muscles as an adult • Loss in muscle size • Problems walking (delayed walking)