Podcast
Questions and Answers
What primarily determines whether a smooth muscle cell contracts or relaxes?
What primarily determines whether a smooth muscle cell contracts or relaxes?
- The absolute amount of negative input only.
- The net input, considering both positive and negative influences. (correct)
- The absolute amount of positive input only.
- The presence of mechanically gated channels.
Which of the following is an example of electrical (electromechanical) regulation in smooth muscle?
Which of the following is an example of electrical (electromechanical) regulation in smooth muscle?
- The influence of paracrine agents.
- Activation of ligand-gated channels by hormones.
- Opening of voltage-gated calcium channels due to membrane depolarization. (correct)
- The autonomic nervous system.
Depolarization in smooth muscle cells, leading to contraction, can be caused by:
Depolarization in smooth muscle cells, leading to contraction, can be caused by:
- Opening of voltage-gated $Ca^{2+}$ channels. (correct)
- Increased activity of the sodium-potassium pump.
- Influx of sodium ions through ligand-gated channels.
- Activation of potassium leak channels.
What is the primary characteristic of 'slow wave potentials' in smooth muscle cells?
What is the primary characteristic of 'slow wave potentials' in smooth muscle cells?
Which of the following is an example of pharmacomechanical regulation in smooth muscle?
Which of the following is an example of pharmacomechanical regulation in smooth muscle?
In the context of smooth muscle regulation, what is the role of $IP_3$?
In the context of smooth muscle regulation, what is the role of $IP_3$?
How do neurotransmitters, hormones, and paracrine signals influence smooth muscle contraction?
How do neurotransmitters, hormones, and paracrine signals influence smooth muscle contraction?
A key difference between smooth muscle and skeletal muscle regulation is that in smooth muscle:
A key difference between smooth muscle and skeletal muscle regulation is that in smooth muscle:
What role does Myosin Light Chain Phosphatase (MLCP) play in smooth muscle contraction?
What role does Myosin Light Chain Phosphatase (MLCP) play in smooth muscle contraction?
Oscillating membrane potentials that regularly reach threshold are characteristic of:
Oscillating membrane potentials that regularly reach threshold are characteristic of:
What is the function of Nitric Oxide (NO) in smooth muscle regulation?
What is the function of Nitric Oxide (NO) in smooth muscle regulation?
What is a primary characteristic of pharmacomechanical coupling?
What is a primary characteristic of pharmacomechanical coupling?
How does increased intracellular calcium ($Ca^{2+}$) lead to smooth muscle contraction?
How does increased intracellular calcium ($Ca^{2+}$) lead to smooth muscle contraction?
Which regulatory mechanisms are considered part of electrical (electromechanical) regulation in smooth muscle?
Which regulatory mechanisms are considered part of electrical (electromechanical) regulation in smooth muscle?
What is the role of Rho-associated kinase (ROCK) in smooth muscle contraction?
What is the role of Rho-associated kinase (ROCK) in smooth muscle contraction?
Which type of smooth muscle regulation is primarily involved when the Autonomic Nervous System affects smooth muscle contraction?
Which type of smooth muscle regulation is primarily involved when the Autonomic Nervous System affects smooth muscle contraction?
In smooth muscle cells, what happens to membrane potential during electrochemical coupling?
In smooth muscle cells, what happens to membrane potential during electrochemical coupling?
How do pacemaker potentials lead to contraction in smooth muscle?
How do pacemaker potentials lead to contraction in smooth muscle?
How are calcium levels restored in the SR?
How are calcium levels restored in the SR?
Increased IP3 results in?
Increased IP3 results in?
Flashcards
Electrical (electromechanical) regulation
Electrical (electromechanical) regulation
Regulation through electrical signals like mechanically-gated, voltage-gated and ligand-gated Ca2+ channels.
Pharmacomechanical regulation
Pharmacomechanical regulation
Regulation via ligands binding to receptors, like autonomic nervous system, hormones and paracrine agents.
Depolarisation (Ca2+ entry)
Depolarisation (Ca2+ entry)
Entry of Ca2+ into the cell due to opening of voltage gated channels, ligand gated channels or stretch activated channels
Slow wave potentials
Slow wave potentials
Signup and view all the flashcards
Pacemaker potentials
Pacemaker potentials
Signup and view all the flashcards
Pharmacomechanical Coupling
Pharmacomechanical Coupling
Signup and view all the flashcards
Smooth Muscle Regulation Signals
Smooth Muscle Regulation Signals
Signup and view all the flashcards
MLCK/MLCP Ratio
MLCK/MLCP Ratio
Signup and view all the flashcards
Smooth vs. Skeletal Muscle
Smooth vs. Skeletal Muscle
Signup and view all the flashcards
Study Notes
- Smooth muscle regulation is complex, involving multiple organs with different functions and various mechanisms to regulate contraction.
- Net input governs whether the cell contracts or relaxes, considering both positive and negative inputs.
Electrical (Electromechanical) Regulation
- Regulation occurs through mechanically gated, voltage-gated, and ligand-gated Ca2+ channels.
- Pacemaker and slow wave potentials also play a role.
Pharmacomechanical Regulation
- Regulation occurs via ligand gated channels/receptors.
- Regulation occurs via the Autonomic Nervous System.
- Hormones and paracrine agents are also involved.
Depolarisation (Ca2+ Entry)
- Depolarization and subsequent Ca2+ entry is caused by voltage gated Ca2+ channels.
- Depolarization and subsequent Ca2+ entry is caused by ligand gated Ca2+ channels.
- Depolarization and subsequent Ca2+ entry is caused by stretch activated channels.
Electrochemical Coupling
- Contraction is accompanied by changes in the membrane potential.
- Spontaneous opening/closing of ion channels influences muscle contraction.
Slow Wave Potentials
- Slow wave potentials occur in a cycle of subthreshold waves.
- Additional stimuli can cause the cell to reach threshold, resulting in contraction.
- Intestines have slow waves and reach threshold when food initiates stretch receptors.
Pacemaker Potentials
- Pacemaker potentials are the oscillating membrane potentials, similar to cardiac muscle.
- Pacemaker potentials regularly reach threshold.
- Phasic smooth muscles of the gut use this mechanism.
Pharmacomechanical Coupling
- Contraction occurs without changes in membrane potential.
- Neurotransmitters such as ACh and adrenaline are related to this.
- Hormones like angiotensin II are related to this.
- Paracrine signals like nitric oxide are related to this.
Neurotransmitters/Hormones/Paracrine Signals
- IP3 release opens IP3 channels on the sarcoplasmic reticulum (SR), leading to the release of Ca2+.
- Altered MLCK/MLCP ratio influences cross-bridge activity causing an increase.
- Paracrine signals, including histamine, adrenaline, and nitric oxide, affect smooth muscle.
Smooth Muscle vs. Skeletal Muscle
- Smooth muscle stimulus can be stimulatory or inhibitory, whereas skeletal muscle is usually only stimulatory.
- Smooth muscle stimulus is not always a nerve unlike skeletal muscle.
- Changes in membrane potential in smooth muscle are due to Ca2+ and not Na+.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
