Chapter 6 - Muscular Anatomy Flashcards
What are the four unique characteristics of muscle tissue?
a) excitability
b) contractility
c) extensibility
d) elasticity
What is excitability in the context of muscle tissue?
Excitability is the ability of the muscle tissue to carry an electrical impulse called an action potential, which initiates the muscle contraction.
What is contractility in the context of muscle tissue?
Contractility is the response of the muscle cell to the electrical impulse. The muscle cell responds by shortening, pulling the two ends of the muscle towards each other.
What is extensibility in the context of muscle tissue?
Extensibility allows the muscle to be lengthened without damaging the tissue.
What is elasticity in the context of muscle tissue?
Elasticity allows the muscle to return to its resting length.
What are the types of muscle tissue?
a). Skeletal muscle
b). Cardiac muscle
c). Smooth muscle
What is the function of skeletal muscle?
It is muscle connected to the skeleton by being attached to two bones across a joint. These muscles produce the force required for human movement.
This chapter focusses on the Skeletal muscle tissue.
What is the function of cardiac muscle?
Cardiac muscle allow the heart to pump blood to the tissues.
What is the function of smooth muscle?
Smooth muscle is found in organs such as the digestive, urinary and circulatory system. When they contract, they do not exert much force.
How many skeletal muscles does the human body have?
The human body has over 600 skeletal muscles. Skeletal muscle is the most abundant type of of muscle in the body.
What are the main functions of the skeletal muscles
- provide force for human movement
- maintain upright posture
- generates heat to maintain constant body temperature
What is the structure of a skeletal muscle?
- made up of thousands of elongated rod-shaped cells called muscle fibers
- Muscle fibres are grouped into bundles of 10 to 150 muscle fibres in each bundle
HOw are the bundles of muscle fibres held together to form the muscle?
- Each bundle of muscle fibres are held together by the epimysium - which is the shiny outer layer of connective tissue surrounding the muscle.
- The layers of connective tissue amalgamate at the ends of the muscle to form the tendon.
- Tendons attach the muscle to the bone.
- Tendons and the epimysium (connective tissue) form the fascial tissue of the body.
Tendons attach
a). muscle to bone
b). muscle to muscle
c). bone to bone
a). Muscle to bone
What is the structure of a muscle fibre?
Made up of a lot of thinner fibres call myofibrils
What is the structure of a myofibril?
It is made up of sarcomeres - which are the basic unit for muscle contraction.
What is the structure of a sarcomere?
Composed of two proteins:
1). Actin
2) Myosin
When the muscle contracts, these two proteins slide along each other.
What are the types of muscle contractions?
1). Concentric contraction
2) Eccentric contraction -
3) Isometric contraction
What is a concentric muscle contraction and give an example?
when the muscle shortens (a bicep curl)
what is an Eccentric muscle contraction and give an example?
when the muscle lengthens (lowering phase of a bicep curl or elbow extension)
What is an isometric muscle contraction and give an example?
muscle exerts force to counteract an opposing force -
eg. holding a plank position (counteracting gravity)
eg. pushing your right fist into your left hand and exerting pressure from both arms)