Chapter 11 - Muscular System Flashcards
What are the different types of fibers in skeletal muscle?
Red fibers: slow twitch
- high myoglobin
White fibers: fast-twitch
- a lot less myoglobin
Tell me about the nuclei of smooth muscle
Single nucleus
What is myogenic activity and which muscle types fall under this category?
Can contract without nervous system input
- example: muscle cells contract directly in response to stretch or other stimuli
BOTH SMOOTH AND CARDIAC MUSCLE exhibit myogenic activity
Tell me about the nuclei of cardiac muscle
Usually uninucleated
Some cells may have 2 nuclei
What type of cell to cell communication is found in cardiac muscle?
Gap junctions
Flow of ions directly allows for rapid and coordinated muscle and effective contraction of cardiac muscle
Which muscle type is calcium required for contraction?
All three
What is the sarcomere?
The contractile unit of skeletal muscle
What are the thick and thin elements of sarcomeres made up of?
THICK: myosin
THIN: (ac’thin’) = actin
+ troponin and tropomyosin
the T from actin, T from tropos
What do the different bands and lines represent on sarcomeres?
Z-lines: boundaries of each sarcomere
*Z is end of alphabet!
M-line: runs down centre
**M is middle of myosin
I-band: exclusively thin filaments
**(I is a thin letter!)
H-zone: thick filaments
**H is a thick letter
A-band:n. Thick filaments with overlap of thin filaments
**A is for All the thick filament, whether or not it is overlapping
Which bands become smaller vs stay same size during sarcomere contraction?
H, I , Z, M lines get smaller
A-band: stays the same!!
What is axial vs appendicular skeleton?
Axial: midline structures
- skull
- vertebral column
- ribcage
- hyoid bone
APPENDICULAR:
- limbs
- pectoral girdle
- pelvis ‘
What germ line is bone from?
Mesoderm
What does vitamin D do for bone?
Increases resorption
- makes bones stronger
Adductors vs abductors
Adductors: towards midline
Abductors: away from midline
