Tissues - Muscles Flashcards
The types of muscle differ in terms of…
- where they are found
- structure of their cells
- how they are activated to contract
Characteristics of skeletal muscle
- striated
- voluntary control
- cylindrical cells
- refractory period- 1-2 milliseconds
- attached to bone
- 3-30cms long
Characteristics of cardiac muscle
- 50-100 micrometers
- striated
- intercalated discs
- refractory period 250 milliseconds
- auto rhythmic
What types of myfilaments make up a myfibril?
- actin
- myosin
- elastic
What are motor units?
One nerve fibre and all of the muscle fibres it inervates
Why are there multiple motor units in each muscle?
- some able to rest and recover while others are active
- differential rates of fatigue in a muscle allow for sustained function
What makes up an intercalated disc?
- gap junctions
- desmosomes
Characteristics of smooth muscle
- fusiform
- non-striated (contractile unites arranged irregularly)
- 20-500 micrometers
- gap junctions
- capable of cell division
- dense bodies connect cell to each other
- auto rhythmic
- refractory period 300-800ms
What is the refractory period of skeletal muscle?
1-2 milliseconds
What is the refractory period of cardiac muscle?
250 milliseconds
What is the refractory period of smooth muscle?
300-800 milliseconds
What is smooth muscle specialised for?
Slow, prolonged contraction
What does auto-rhythmic mean?
Can contract independent of nervous stimuli
What does smooth muscle respond to?
Chemicals, hormones, ph, CO2, O2, temperature, stretch
