A&P - Chapter 17 (Part 1) Flashcards
What do muscles contribute to?
The body’s framework/shape and functions
What are 3 general functions muscles help with?
- Movement
- Heat production
- Posture
What are 3 functional characteristics of skeletal muscle tissues?
- Excitability
- Contractility
- Extensibility
Excitability
Ability to be stimulated
Contractility
Ability to contract/shorted
- movement
Extensibility
Ability to extend/stretch, allow muscles to return to their resting length
What are 3 types of muscle tissues?
- Skeletal
- Cardiac
- Smooth
What are 2 other names for skeletal muscle?
- Striated
2. Voluntary
What % do skeletal muscles represent in weight?
40-50%
Where are skeletal muscles attached to?
Bones
What appear on skeletal muscles?
Multi-nucleated cells/fibre
- arranged around periphery of cell
Another word for muscle cells?
Muscle fibres
- threadlike appearance
Sarcoplasmic reticulum
Membrane that is responsible for Ca release and storage
What do muscle fibres contain? (4)
- Many mitochondria
- Several nuclei
- Myofibrils
- T-tubules
Myofibrils
Numerous fine fibres packed close together in the sarcoplasm
T-tubules
Inward extensions of the sarcolemma that allow nerve impulses to move deeper into the fibre
What are myofibrils made up of?
Myofilaments
Myofilaments
Very fine, threadlike structures
What makes up myofilaments?
4 types of proteins
- 2 myosin
- 2 actin
What protein makes up the thick myofilaments?
Myosin
What proteins make up the thin myofilaments?
Actin
Sarcomeres
Myofilaments (actin and myosin) are arranged in repeating segments
What is a sarcomere?
Is the basic functional (contractile) unit of muscle fibres
What are individual sarcomeres separated by?
Z-line
- Z-disks
When will a skeletal muscle no longer be in the rest position?
When it gets stimulated by a nerve pulse
How does a nerve pulse arrive to the muscle?
Through a motor neuron
When does the motor neuron stop its impulse movement?
When is reaches the neuromuscular junction
- synapse
Synapse
Microscopic gap between the end of the motor neuron and the sarcolemma of the fibre
