Muscle Anatomy Flashcards
What are 5 reasons why SKELETAL MUSCLE contracts?
1) Move BONES for locomotion
2) Maintain HOMEOSTASIS e.g. shivering, respiration
3) Maintain posture and balance
4) Support soft tissue e.g. abdominal wall
5) Guards entrances and exits e.g. voluntary control of urination and defecation
Each MUSCLE is surrounded by________?
EPIMYSIUM
S & F of EPIMYSIUM
S - CT surrounding each whole MUSCLE, dense collagen fibers
F - Separates MUSCLE from other organs, continuous with TENDON and PERIOSTEUM
A MUSCLE is made up of many __________
FASCICLES
S & F of PARALLEL MUSCLE
Give an example
S - FASCICLES run side by side along length of MUSCLE
F - Can shorten the most
Example = Most MUSCLES, BICEPS BRACHII
S & F of CONVERGENT MUSCLE
Give an example
S - FASCICLES converge like a fan
F - Can vary direction of pull
Example = PECTORALIS MAJOR
S & F of PENNATE MUSCLE
What are the 3 different types?
Give an example
S - Short FASCICLES attach to central TENDON like a feather, has many FASCICLES = many FIBERS F - Can produce most tension 1) UNIPENNATE e.g. EXTENSOR DIGITORUM 2) BIPENNATE e.g. RECTUS FEMORIS 3) MULTIPENNATE e.g. DELTOID
S & F of CIRCULAR MUSCLE
Give an example
S - FASCICLES arranged in concentric rings around an opening aka sphincter
F - Allows control of opening/closing
Example = Mouth, anus
Each MUSCLE FASCICLE is surrounded by _________
PERIMYSIUM
S & F of PERIMYSIUM
S - Made of COLLAGEN and ELASTIC FIBERS
F - Supports larger blood vessels/branching nerves, continuous with ENDOMYSIUM and EPIMYSIUM
PERIMYSIUM is made up of many ______ ____ = ______ ____
MUSCLE FIBERS = MUSCLE CELLS
Each MUSCLE FIBER is surrounded by _________
ENDOMYSIUM
S & F of ENDOMYSIUM
S - Made of loose CT
F - Supports CAPILLARIES to nourish FIBERS, Supports nerve endings to stim. FIBERS, continuous with PERIMYSIUM
What is each MUSCLE FIBER composed of?
1) SARCOLEMMA
2) TRANSVERSE TUBULES
3) SARCOPLASMIC RETICULUM
4) MULTIPLE NULCEI
5) MITOCHONDRIA
6) MYOFIBRILS
What is the SARCOLEMMA?
A MUSCLE CELL MEMBRANE
