Block 3: Muscular System - Lecture 3.1 Flashcards
What are the three types of muscle tissue?
- Skeletal muscle
- Cardiac muscle
- Smooth muscle
What do all three muscle tissue types primarily rely on?
PROTEINS!!
The principles and concepts of what muscle tissue type help us to understand the other two muscle tissue types?
Skeletal muscle
What is the basic function of all muscle tissue?
To generate tension/force
How does the structure of muscle relate to its function?
In the body, structure always determines function.
What level of organization allows us to understand disease?
The molecular level
What level of organization corresponds with tissue and cellular organization?
Organ (structure) level
- connective tissue determines muscular function
In skeletal muscle cells, what role do proteins play?
Function to generate tension using excitation-contraction modeling
When talking about muscle mechanics, what is being referred to?
HOW muscles generate force
What does performance have to do with skeletal muscle?
Performance can change the anatomy and physiology of skeletal muscle
What does energy have to do with skeletal muscle?
Skeletal muscle tissue aids in metabolism and ATP production
What are the 6 major functions of skeletal muscle?
- Locomotion
- Facial expression
- Posture and body position
- Control of body openings and passages
- Regulation of body temperature
- Metabolism and endocrine functions
Describe how locomotion relates to the function of skeletal muscle.
Movement from place to place
Describe how facial expression relates to the function of skeletal muscle.
Understand how a person is feeling
- attachments with the CT of the skin, especially the fascia of the dermis
Describe how posture and body position relate to the function of skeletal muscle.
Muscles keep body upright
Describe how control of body openings and passages relate to the function of skeletal muscle.
VOLUNTARY!!
- controls what gets ingested (upper esophageal sphincter)
- controls exit of waste (external anal sphincter)
- controls urine elimination (external urethral sphincter)
Describe how regulation of body temperature relates to the function of skeletal muscle.
Muscle contraction generates heat to maintain temperature homeostasis
Describe how metabolism and endocrine functions relate to the function of skeletal muscle.
- Metabolism aids in the produced of ATP
- Endocrine system produces hormones
What does “voluntary contraction” mean?
We choose when to initiate movement
- true for most skeletal muscle
- requires nervous system input
What does is mean when a skeletal muscle is “automatic”?
Movement occurs without thought
What contraction pattern (voluntary or automatic) does the Diaphragm follow?
BOTH!
- automatic: typical, every day usage
- voluntary: ability to change its activity by taking a deep breath or holding a breath
What are “automated, rhythmic sequences”?
Large coordination or different muscle groups by signals sent through the spinal cord by neurons
What is an example of an automated, rhythmic sequence?
WALKING!
What are 4 examples of human movement in a practical setting?
- Fitness
- Dancing
- Clinical applications
- Physical therapy
How has technology helped us to understand human movement?
Models of skeletal muscle dynamics are used to develop engineering hardware/software to create robots that mimic human movements
Muscles (pull/push) on bones.
PULL!
What two components of skeletal muscles are used to predict the action of a muscle?
- Origin
- Insertion
What is the “origin” of a muscle?
Place where muscle starts on a bone
- typically a fixed/stationary location
What is the “insertion” of a muscle?
Place where muscle ends on a bone
- muscles have sculpted bones based on their pulling
The (origin/insertion) of a muscle moves towards the (origin/insertion).
Insertion, origin
Identify the origin, insertion, and the muscle associated with flexion of the forearm.
- Origin: Scapula (above the Glenoid Cavity)
- Insertion: Radius (radial tuberosity)
- Muscle: Biceps brachii
What is the format when stating a muscles action?
- (Action) OF the (segment that is moving)
- (Action) AT the (joint that is moving)
What is another way to say “flexion of the forearm”?
Flexion at the elbow
When describing joint movements, what is the body positioned in?
Standard anatomical position
- body is fully extended except for the feet
What is “flexion”?
Movement to reduce the angle at a joint
What is “extension”?
Movement to increase the angle at a joint
What is “hyperextension”?
Movement beyond standard anatomical position/full extension
What is “abduction”?
Movement away from the midline/longitudinal axis of the body
- typically occurs along the frontal plane
What is “adduction”?
Movement towards the midline/longitudinal axis of the body
- typically occurs along the frontal plane
What is reverse muscle action?
Origin moves towards the insertion
- insertion is anchored
- ex: pull-up & standing up
What are the 7 ways to classify a muscle based on bundle orientation?
1) Fusiform
2) Parallel
3) Triangular
4) Unipennate
5) Bipennate
6) Multipennate
7) Circular
What is the cross-sectional area of a muscle?
Force of a muscle depends on CSA
- Parallel: smaller CSA = generates less force
- Unipennate: larger CSA = generates more force
What allows different sections of the same muscle to be used at different times?
Different sections of the muscle fibers
What is an example of a Fusiform muscle?
Biceps brachii
What is an example of a Parallel muscle?
Rectus abdominis
What is an example of a Triangular muscle?
Pectoralis major
What is an example of a Unipennate muscle? How are the fibers oriented for a Unipennate muscle?
Palmar interosseous
- fibers oriented at an angle
What is an example of a Bipennate muscle?
Rectus femoris
What is an example of a Multipennate muscle?
Deltoid
What is an example of a Circular muscle?
Orbicularis oculi
What are the 4 ways to classify a muscle based on action?
1) Agonist
2) Antagonist
3) Synergist
4) Fixator
What is an Agonist?
Muscle performing the action
- produces movement
- prime mover
What is an Antagonist?
Muscle performing the opposite action of an agonist
- based on the action of the agonist
What is a Synergist?
Helps agonist to make movement more efficient
What is a Fixator?
A special synergist that prevents movement at the muscle origin
- fix the body in place while the surrounding muscles do the action
What are the 3 ways to classify a muscle based on how it moves?
1) First Class Lever
2) Second Class Lever
3) Third Class Lever
What is a First Class Lever? What is a mechanical advantage of First Class Levers?
Joint where the Fulcrum is in the middle
- ex: atlanto-occipital joint
Ability to use less force to move a greater load as the distance between the fulcrum and effort increases
- MA > 1
What is a Second Class Lever? What is a mechanical advantage of Second Class Levers?
Joint where the Load is in the middle
- ex: standing on tip-toes
- typically holds the load of the entire body
Load is closer to the fulcrum than the effort is to the fulcrum
- MA > 1
What is a Third Class Lever? What is a mechanical advantage and disadvantage of Third Class Levers?
Joint where the Effort is in the middle
- ex: hinge joint
- load is what is being carried
- effort is the insertion portion of the muscle performing the action
Advantage: increase range of motion and velocity of movement with small adjustments
Disadvantage: force from effort will always be greater than that of the load
- MA < 1
What is torque?
Force that moves at an angle
