Anatomy Lecture Exam Review

Anatomy Lecture Exam Review - Skeletal Muscles 1 Composed...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Skeletal Muscles 1. Composed of Fasicles 2. Each fascicle is made up of muscle fibers 3. Each skeletal muscle is an organ 4. Attachments- Dense Regular CT: 2 forms a. Tendon = cord-like b. Aponeuroses = flat, sheet-like 5. Connective Tissue Wrappings a. Entire muscle is covered with Epimysium b. Each fascicle is covered with Perimysium c. Each muscle cell/fiber is covered with Endomysium Microscopic Anatomy of Skeletal Muscle 1. Each fiber cell is composed of myofibrils. 2. Each myofibril contains myofilaments a. Two kinds i. Thick Myofilaments = myosin protein ii. Thin Myofilaments = actin protein 3. Have organelle like structures- lysosome, nucleus, golgi bodies etc. a. Smooth E.R.= stores Ca++ ions and releases them during muscle contraction 4. Muscle Cell Membrane= Sarcolemma 5. Muscle Cytoplasm = Sarcoplasm 6. Transverse Tubules = a. Passageway for nutrients b. Exits for waste c. Allow nerve impulse to travel rapidly from sarcolemma to inner part of muscle cell 7. Banding Pattern (Striations)
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
a. Light Bands = I-bands i. THIN MYOFILAMENTS ONLY b. Dark Bands = A-bands i. Thick and thin myofilaments c. Z-line (Z-disc) i. Darker portion in the middle of I-bands d. H-Zone i. Lighter portion in the middle of A-bands ii. ONLY THICK MYOFILAMENTS e. Sarcomere i. Runs from Z-line to Z-line (functional contractile unit) Contraction of Skeletal Muscle 1. Nerve impulse sent from brain/spinal cord to muscle via the axon of a motor neuron 2. The axon meets the muscle fiber/cell at the neuromuscular junction 3. The axon releases a neurotransmitter called acetylcholine which binds to the sarcolemma 4. A nerve impulse is generated in the sarcolemma and it passes down the T-tubules. As a results the sarcoplasmic reticulum releases Ca++ ions. 5. The Ca++ ions bind to the thin myofilaments which allows the thick myofilaments thin myofilaments. 6. Myofilaments slide over one another; sarcomere shortens; muscle contracts 7. When the nerve impulse stops, Ca++ ions return to the sarcoplasmic reticulum and the myofilaments slide back to their resting state. Muscles of Facial Expression
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 10

Anatomy Lecture Exam Review - Skeletal Muscles 1 Composed...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online