Lecture 7: Muscle Tissue Overview Flashcards Preview

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Flashcards in Lecture 7: Muscle Tissue Overview Deck (15):

Compare and contrast the 3 basic types of muscle tissue

1. Skeletal muscle tissue: attach to bones and skin, striated, voluntary
2. Cardiac muscle tissue: only in heart, striated, involuntary
3. Smooth muscle tissue: in the walls of hollow organs eg stomach, urinary bladder, and airways
-not striated


List the 4 special characteristics of muscle tissue

1. Excitability: ability to receive and respond to stimuli
2. Contractility: ability to shorten when stimulated
3. Extensibility: ability to be stretched
4. Elasticity: ability to recoil to resting length


What are the 4 functions of muscle

1. Heat generation (especially skeletal muscle)
2. Stabilizing joints
3. Maintains posture and body position
4. Movement of bones or fluids


What are the 3 different types of connective tissue found in the skeletal muscle?

1. Epimysium: dense regular connective tissue surrounding entires
2. Perimysium: fibrous connective tissue surrounding fascicles (groups of muscle fibers)
3. Endomysium: fine areolar connective tissue surrounding each
muscle fibre
Refer to slide 8


Contraction doesn't always shorten a muscle. What's the difference between isometric and isotonic?

Isometric contraction: no shortening, muscle tension increases but does not exceed the load
Isotonic contraction: muscle shortens because muscle tension exceeds the load


What is muscle tone

Constant, slightly contracted state of all muscles
-due to spinal reflexes that activate groups of motor units alternately in response to input from stretch receptors
-keeps muscles firm healthy and ready to respond


Isotonic contractions are either concentric or eccentric. What's the difference?

Concentric contractions: the muscle shortens and does work
Eccentric contractions: the muscle contracts as it lengthens


What is an isometric contraction?

The load is greater than the tension the muscle is able to develop
-tention increases to the muscles capacity, but the muscle neither shortens or lengthens


Muscle fibre type is classified according to two characteristics: speed of contraction: slow or fast

Slow fibres: red- postural muscles
Fast fibres: white- fingers


Smooth muscles usually have two layers. What are they?
What kind of nerve fibres inner ate smooth muscle

Longitudinal and circular
Innervated by autonomic nerve fibres


What are the 4 functional groups of skeletal muscles?

1. Prime movers: provide the major force for producing a specific movement
2. Antagonists: opposes or reverses a particular movement
3. Synergists: add force to a movement, and reduces undesirable or unnecessary movement
4. Fixators: Synergists that immobilize a bone of muscles origin


Naming skeletal muscles. What are the 7 methods used in naming skeletal muscles?

1. Location
2. Shape eg deltoid (triangle)
3. Relative size eg Maximus, minimus, longus (long)
4. Direction of fibres or fascicles eg rectus (fibres run straight), transverse, and oblique
5. Number of origins eg biceps (2 origins) and triceps (3 origins)
6. Location or attachments: name according to point of origin or insertion
7. Action eg flexor or extensor


What are the 5 different arrangement of fascicles

1. Circular: fascicles arranged in concentric rings (eg orbicularis oris)
2. Convergent (fascicles converge towards a single tendon insertion eg pectoralis major
3. Parallel: fascicles parallel to the long axis of a strap like muscle eg sartorius
4. Fusiform: spindle shaped muscle with parallel fibres eg biceps brachii
5. Pennate: short fascicles attach obliquely to a central tendon running the length of the muscle eg rectus femoris


Name the muscles of facial expression

Epicranius: it's a bipartite muscle consisting of the frontalis, occipitalis, and galea aponerotica which is a cranial aponeurosis connecting the above two muscles. The two muscles have alternate actions of pulling the scalp forward and backward


Muscles of mastication and tongue movement:

There are 4 pairs involved in mastication:
1. Prime movers of jaw closure: temporalis and masseter
2. Grinding movements: medial and lateral pterygoids
All are innervated by cranial nerve 5: trigeminal nerve