Muscles 3 Flashcards
Muscle tone
Skeletal and smooth muscles are under a weak contracted state at rest
- regulated by the brain and spinal nerves
- motor units are recruited and cycled around
What is the function of muscle tone?
- Supports posture
- muscle readiness
- circulation
- joint stability
Muscle coordination
Muscles either work together or against each other to create smooth and purposeful movements
Types:
Agonists(prime mover): muscles responsible for target movement
Synergists: assists the agonist
Antagonists: oppose the actions of the agonist
Identify the muscles that belong to each functional group during elbow flexion(agonist, synergistic, antagonist)
Agonist(prime movers): biceps brachii and brachialis
• synergists: deltoid
• antagonists: triceps brachii
True or False:
All skeletal muscles are directly attached to the bone
False
Muscle Attachments
There are 2 types:
Direct- muscle to bone or cartilage
Indirect- through tendons or aponeruroses
Aponeruroses- broad, flat like connective tissue
A typical muscle connects to at least 2 places
- the origin: the proximal end site
- insertion: the distal end site
Muscle fatigue
Is the decline of a muscle to maintain tension after a long stimulation
What can co tribute to this?
- decreased ATP
• decreased glycogen - buildup of lactic acid and imbalance in Na* and K+
For muscles to return to its pre-excersise state
restore oxygen reserve (in myoglobin)
• restore glycogen reserve
• restore creatine phosphate reserve
Delayed onset muscular soreness(DOMS)
Is a delayed sore, aching, painful muscle after unaccustomed intense excercidd
The soreness comes from tissue injury cause by mechanical stress
Muscle Cramps
A sudden, painful and involuntary muscle cobtractuon
How does the following scenarios contribute to muscle cramps?
Look at image
FIRST: electrolyte imbalances due to excess sweating, dehydration, excessive muscle heat.
• SECOND: abnormal sensory activities from muscle fibres can trigger motor neurons to fire randomly.
Electromyography(EMG)
a technique that measures the electrical activity of skeletal muscle fibres at rest and during contraction.
This was used to understand
• muscle activation
• muscle fatigue
• motor unit recruitment
• neuromuscular disorders
Electromyography:
There are 2 types
Surface and Intramuscular EMG
Categorize the following descriptions as either surface (S) or intramuscular (M) EMG recordings.
• Invasive-
• Cannot discriminate between activity of adjacent muscles
• Produces consistent and accurate information for diagnostic purposes
• Can analyze the activity of a single motor unit
• May be affected by adipose tissue (fat)
- M
- S
- M
- M
- M
Electrical stimulation
Is used in skeletal muscles to send impulses to the body to stimulate or inhibit muscle contractions
Other names are:
- electrical muscle stimulation(EMS)
- neuromuscular electrical stimulation(NMES)
What are the benefits of using electrical muscle stimulation?
- muscle strengthening and recovery
- pain relief
- improves performance
- improves blood circulation
Rank the 3 muscle fibre types from the most to least regenerative
- Smooth
- Skeletal
- Cardiac
Smooth muscles
Are found in the walls of hollow organs and the tracts of the respiratory, urinary, and reproductive systems
Are organized into single unit and multi unit
Single unit:
- contracts as 1 combined unit
Eg. Walls of stomach, intestines and urinary bladder and the uterus
Multiunit:
- contacts in small groups
Examples:
Iris, ciliary muscles, large airways of the lungs
Which organization of smooth muscles do the following structures belong to
walls of the digestive tract - Single
• walls of urinary bladder → Single
• erector pili muscle -> Multi
• wall of large airway -multi
Which feature contributes to the smooth muscle’s rhythmicity and ability to contract as a unit?
A. troponin complex
B. gap junctions
C. varicosities
D. caveolae
B
Smooth muscles have caveolae
Which are infoldiings that have calcium channels that allow an influx of extracellular Ca
Smoother muscles can be contracted by
- autonomic nervous system
- stretch
- local factors
- hormones
Loop at independent work
