L9/10- Smooth muscle Flashcards
shape of smooth muscle cells
spindle shaped
nucleus in smooth muscle
single large central nucleus
smooth muscle cells are not …… unlike skeletal and cardiac
striated- no sarcomeres
contraction in smooth muscle relies on
actin-myosin interactions
type of contraction
slower, but more sustained- requires less ATP
how do smooth muscle cells aggregate
form sheets, bundles or layers
have numerous
caveolae (smal cave-like invaginations
similarities to striated muscle
- Contain actin and myosin contractile proteins o Anchored by a dense body (z-disc) o Calcium supplied by SR
what sort of stimuli do smooth muscle respond to
- Nerve signals- autonomic nervous system - Hormones - Mechanical- distension - Drugs - Local concentration of blood gases
smooth muscle distribution
Forms contractile walls of passageways or cavities - Vascular structures - Gut - Respiratory - Genitourinary system
smooth muscle is completely
involuntary
clinical disorders related to smooth muscle
- Primary hypertension - Dysmenorrhea- painful menstruation - Asthma - Abnormal gut mobility (IBS) - Incontinence
too much contraction of smooth muscle
can lead to damage
relaxed vs contracted smooth muscle
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smooth muscle innervation
Axons of the ANS do not form highly organised NMJs with smooth muscle. A series of NT-filled buneles called varicosities-form motor units.