Muscular System PDF

Muscular System Dr.Sayed Jahin Lecturer of anatomy and embryology  Introduction There are more than 600 skeletal muscles in the body It represent from 40 to 50 of the body weight Muscles, along with the skeleton, determine the form and contour of the body Functions of skeletal Mu...

Muscular System Dr.Sayed Jahin Lecturer of anatomy and embryology  Introduction There are more than 600 skeletal muscles in the body It represent from 40 to 50 of the body weight Muscles, along with the skeleton, determine the form and contour of the body Functions of skeletal Muscles Body movements Maintaining Posture Stabilizing Joints Body positions Generating heat  Definition of Muscle: ✓ Is the only body tissue able to contract, as it becomes shorter in response to a stimulus that bring about movements of different body parts.  Types of Muscles 3 types 1- Skeletal muscles. 2- Smooth muscles. 3- Cardiac muscle.  1- Smooth Muscles Spindle shaped, smooth, not striated and uninucleate. Involuntary. Found in the lining of blood vessels and the wall of internal organs such as urinary bladder and gastro- intestinal tract. Supplied by autonomic nerves  2- Cardiac Muscles Rectangular in shape They are found only in the heart. Involuntary (only responds to direct electrical stimulation) Supplied by autonomic nerves The cardiac muscle has central one nucleus, like smooth muscle, and Striated like skeletal muscle  3- Skeletal Muscles ▪It consists of muscle fibers, arranged into bundles as tubes. This type of muscle is to known as skeletal, striated and voluntary. ❑ Skeletal means that the muscle is mostly attached to bone. ❑ Striated means it is banded and showed longitudinal and transverse striations. ❑ Voluntary means it is under our own control as it supplied by somatic nervous system. ❑ They are found in the upper limbs, lower, abdomen, head & neck, etc The differences between 3 types of muscles  Parts of Skeletal Muscle 1- Origin: It is the fixed part. It is usually attached to the bone. 2- Insertion: It is the movable part. It may be attached to bone, cartilage. skin, deep fascia or other muscle. 3- Fleshy (Belly) part: is contractile part, and is the thicker, middle region of muscle. 4- Tendon: The fibrous cord and non- 5- Aponeurosis: It is a flattened contractile part of the muscle which tendon of fibrous tissues; connect attaches muscle to the bone either in the muscles with the bone and origin or insertion as tendon Achilles. support them as plantar aponeurosi of the foot. Plantar Aponeurosis  Types of the Skeletal Muscles Skeletal muscles is classified according to the arrangement of their fibers into the following groups: 1- Muscles with parallel fibers: A. Quadrilateral : B. Strap-like: C. Strap-like with intersections D. Fusiform 2- Muscles with Oblique fibers: A. Pennate: (unipennate – bipennate – multipennate – circumpennate) B. Triangular C. Circular D. Convergent  1- Muscles with parallel fasciculi Sternomastoid 1-Quadrilateral: thyrohyoid 2-Strap-like 3-Strap-like with tendinous intersections: Rectus abdominis. 4-Fusiform  2- Muscles with Oblique fibers 1- Pennate Type 1-Unipennate looks like half a feather. the fibers are attached to one side of a tendon. 2- Bipennate; the fibers attached to both sides of a tendon. 3- Multipennate: multiple rows of muscle fibers attached to multiple tendon, (multi- bipennate). 4- Circumpennate: The muscle fibers are attached to all sides of the tendon. Circumpennate 2-Triangular oblique muscles The fibers arranged in triangular shape, as: trapezius muscle  3-Circular Type Named as Sphincter Is arranged in a circle It allows closure of the eyes, mouth, etc.  4- Convergent Type Is broad at its origin and tapering to a narrower insertion. EX. Pectoralis major muscle. Common questions 4-The contractile and fleshy part of skeletal muscle is 1-The fixed part of skeletal muscle is the: called: - a) Origin a) Tendon b) Insertion b)Aponeurosis c) Tendon c) Belly d) Fleshy part d) Insertion 2-The type of the muscles found in the wall of blood vessels and internal organs is? 5-The type of muscles found in the upper limbs are: a)Cardiac muscles a)Cardiac b)Skeletal muscles b)Skeletal c)Smooth c)Smooth muscles d) Skeletal pennate d)Skeletal pennate muscles 3-Skeletal muscles are also known as 6-A fibrous cord which attaches muscle to the bone is: a)Striated muscles a) Tendon b)Aponeurosis b)Impulsive muscles c) Belly c)Reflexive muscles d Insertion d)Adipose muscles ) 7-When the fibers of the muscles attached to 9- Which muscle named as sphincter? both sides of a tendon; it is named? a) Convergent a) Unipennate b) Circular b) Bipennate c) Bipennate c) Circumpennate d) Parallel d) Multipennate 10- when the tendon becomes flat; it named as: 8- An example to convergent type of muscles is a) Aponeurosi a) Deltoid b) s Belly b) Trapezius c) Insertion c)Pectoralis major d) Insertion d)Rectus abdominis Thank you