Musculoskeletal System Physiology Flashcards
What are the four main characteristics of muscle tissue?
- Excitability
- Contractibility
- Extensibility
- Elasticity
What characteristic is seen in all muscle types?
Excitability
Definition of excitability?
Ability to receive and respond to stimuli
Definition of contractibility?
Ability to shorten forcibly when stimulated
Definition of extensibility?
Ability to be stretched
Definition of elasticity?
Ability to recoil to resting strength
What are the general functions of muscle tissue?
Movement
Maintain posture and body position
Stabilize joints
Generate heat
Support/protect organs
What are the three main types of muscle?
Skeletal, cardiac, smooth
Function of skeletal?
Movement/posture
Function of cardiac?
Encompasses heart
Function of smooth?
Present through many systems including urinary, vascular, respiratory
What is the appearance of skeletal muscle?
What is the appearance of cardiac muscle?
What is the appearance of smooth muscle?
List whether cardiac, skeletal, and smooth are involuntary or voluntary.
Cardiac- involuntary
Smooth- involuntary
Skeletal- voluntary
List the functions of cardiac, skeletal, and smooth muscle.
Cardiac- blood circulation
Smooth- propels substances along internal pathways
Skeletal- locomotion
List the location of skeletal, cardiac, and smooth muscles.
Skeletal- bones
Smooth- walls of hollow organs
Cardiac- walls of heart
What is the function of the sarcolemma?
action potential conduction
Function of transverse (T) tubule?
increases muscle fiber surface area
What is the function of sarcoplasmic reticulum?
Stores Ca and releases on demand
Discuss the excitation-contraction coupling process.
AP to sliding of myofilaments
Events that transmit AP along sarcolemma (excitation) are coupled to sliding myofilaments (contraction)
Ultimately Ca 2+ released and muscle contracts
Function of ATP?
prepares myosin by binding with actin and moving it to a higher energy state
What type of substance is troponin?
major protein
Function of actin?
myosin binding site, holds tropomyosin and troponin
Function of myosin?
Linking filaments, acts as a motor force
Function of calmodulin?
Ca 2+ binding site
Two functions of tropomyosin?
Stiffen and stabilize the actin core AND block myosin binding sites (in the relaxed state)
Discuss the cross bridge cycle.
Ca 2+ binds to troponin and removes blocking action of tropomyosin
Troponin changes shape
Myosin binding sites are exposed
Myosin and actin creates bridges and cycling begins
Discuss the sliding filament theory.
Muscle fiber contracts when myosin filaments pull actin filaments closer together and shorten sarcomeres
Once all sarcomeres shorten, contraction occurs
