Lecture: Types of Muscle Flashcards
(52 cards)
Myofibroblast
function and appearance
MSC-derived fibroblast activated in response to wound healing. Contains a visibly darker cytoplasm due to ribosomes making collagen
Myoepithelial cells
epithelium-derived cell found in sweat glands that contracts to release secretion from gland
What do the nuclei of smooth muscles look like?
Central, corkscrew-like
Where in the cell are dense bodies found?
Intracellular
Where in the cell are dense plaques found?
Membrane-bound
What are dense bodies bound to?
Actin and Intermediate Filaments (Vimentin/Desmin)
Where is Vimentin found?
IF, found in viscera
Where is Desmin found?
IF, found in vascular system
Sympathetic nerves release?
Norepinephrine
Parasympathetic nerves release?
Acetylcholine
How do Caveolae import Ca2+?
Caveolin targets parts of the membrane containing lipid rafts, causing it to bend inwards, creating a vesicular structure to import Ca2+, Pinocytosis
Explain Myogenic vs Neurogenic
Two differentiations of smooth muscles, allowing the muscle to act either as one unit, or as independent mechanism, allowing for more fine-tuning. aka Unitary vs Multiunit
Myogenic smooth muscle
single-unit, visceral, gap junctions, one axon, responsive to hormones
Neurogenic smooth muscle
multi-unit, independent action (found in iris, arrector pills, large vessels, lung)
Explain Visceral vs Vascular
- Two differentiations of smooth muscle, similar to myogenic and neurogenic, respectively
- Visceral found in walls of organs, neurogenic found in walls of vessels
Where would visceral smooth muscle most likely be found?
Walls of vessels, such as circular smooth muscle in arteries, longitudinal layer in veins, and pericytes in capillaries
Pericytes
- possibly stem cells for vascular smooth muscle
- possibly cause capillaries to become leaky/break BBB
Features of cardiac myocytes
- one, sometimes two central nuclei
- sarcoplasmic cone
- intercalated disc
- intermediate size between skeletal and smooth muscle
What is the intercalated disc made out of?
Complex of 3 junctions:
1) Fascia (Zona) Adherens: f-actin
2) Gap Junctions
3) Desmosome: Intermediate Filament
Types of striated muscle
Skeletal and cardiac
Types of skeletal muscle
Ia (Red)
IIa (Intermediate)
IIb (White)
Types of cardiac muscle
1) Cardiac myocyte (standard)
2) Myocardial endocrine
3) Cardiac conducting
Types of contractile single-cells
- Myofibroblasts
- Myoepithelial cells
Myocardial endocrine cells
- located in Atria
- contain ANP granules
