Smooth Muscle

Front 1

Funtions/Roles of Smooth Muscle

Back 1

Line hollow organs
Regulate Blood Flow/Airway Diameter
Assist in digestion, urination & Childbirth

Front 2

Where are single-unit muscle cells primarily found?

Back 2

GI tract, Repro organs, urinary bladder, small blood vessels

Front 3

T/F: Single & Multi Unit Muscle cells are both found in all organs

Back 3

True, just is different concentrations

Front 4

T/F: Single-Unit Muscle Cells have Gap Junctions

Back 4

True: If 1 cell has AP --> All cells have AP

Front 5

T/F: Multi-Unit Muscle Cells have Gap Junctions

Back 5

False, they are not electrically connected --> All must receive input for AP

Front 6

Multi-unit Smooth Muscle cells are found primarily?

Back 6

Lung airways, Large blood vessels, eye muscles, hair follicles

Front 7

List the 4 contraction states and where they are found

Back 7

1. Contracted (sphincter)
2. Partially Contracted (blood vessels, airways)
3. Phasically Active (stomach, intestines)
4. Relaxed (esophagus, urinary bladder)

Front 8

List the different membrane excitation/signaling mechanisms in smooth muscle

Back 8

1. Hormones/ANS
2. Local Changes
3. Pacemaker Cells
4. Stretching

Front 9

Ca2+ influx mechanisms in smooth muscle from extracellular

Back 9

1. voltage-gated Ca2+ (L-type) channels open from depolarization
2. Ligand-activated Ca2+ channels/G-Protein Coupled Receptors

Front 10

Ca2+ influx mechanisms in smooth muscle from the Sarcoplasmic Reticulum

Back 10

1. Ca2+ induced Ca2+ release (CICR) via RyR in SR
2. G-Protein Coupled Receptor signal --> increase IP3 --> IP3 gated Ca2+ channels --> Ca2+ release from SR

Front 11

What 3 things are different in Smooth Muscle excitation-contraction coupling versus Skeletal Muscle?

Back 11

1. Multiple inputs collectively excite/inhibit
2. Ca2+ taken up by different mechanisms
3. Mechanisms of increase in tension different (due to lack of Troponin)

Front 12

Mechanisms to remove Ca2+?

Back 12

SR Ca2+ ATPase (SERCA)
PM Ca2+ ATPase (PMCA)
Na+-Ca2+ Exchange Pump
Na+-K+ ATPase

Front 13

Describe the Latch State

Back 13

If becomes dephosphorylated while Actin & Myosin still bound, ATP splitting becomes difficult, resulting in an extended contraction that doesn't require a lot of ATP

Front 14

T/F: Smooth Muscle has more Passive Tension

Back 14

True