In cardiac autorhythmic pacemaker cells, how does parasympathetic stimulation make it more difficultfor an action potential to occur?

Q: In what ways are autorhythmic fibers similar to and diff erent from contractile fibers?

A: Heart is a four chambered cardiovascular organ pumping blood throughout the body. The auricles and…

Q: What is the mechanism behind the action potentials in the pacemaker cells?

A: A random, propagating, transitory and fast change of the muscle or nerve cell's resting membrane…

Q: In your study of neuron physiology, you learned that depolarization is dependent on the sodium entry…

A: Heart can initiate contractions on its own by SA node (Sinoatrial node). It doesn't need external…

Q: Describe two effects on the heart of sympathetic nervous system stimulation.

A: Introduction: The nervous system is categorized into the peripheral nervous system (PNS) and the…

Q: Why is it possible for acetylcholine to actually cause an increase in stroke volume, even though…

A: Acetylcholine is one of the most vital neurotransmitter in the human body, that is seen in both the…

Q: How is a cardiac impulse initiated?

A: The transportation of blood in the body is the function of the human circulatory system, also called…

Q: What initiates action potentials in cardiac muscle?

A: Generation of action potential activates the neuron during the generation of stimuli. It is studied…

Q: What is meant by collateral flow?

A: There is a system for supplying oxygen-rich blood to each organ of our body. In the case of the…

Q: Briefly describe the events of excitation-contraction coupling in cardiac muscle cells.

A: Cardiac muscles are also called myocardium, which is a type of muscle in the body that is…

Q: Describe the effect if the atria were to contract at thesame time as the ventricles, or if the…

A: The cardiovascular system is an organ system which distributes blood to all the parts of the body…

Q: How does the AP relate to mechanical events occurring in the heart?

A: The heart is the epicenter of the cardiovascular system and is one of the major organs of the body…

Q: What effect does standing still for a prolonged time haveon the blood pressure in the feet and in…

A: The heart purposely pumps blood at a particular pressure such that blood is able to flow against the…

Q: Fewer action potentials travel up the afferent nerves to the medullary cardiovascular center, and…

A: The cardiovascular center is part of the autonomic nervous system and is responsible for controlling…

Q: What are three of the ways in which cardiac muscle differsfrom skeletal muscle?

A: According to human anatomy, the muscular system is differentiated into three distinct types of…

Q: What prevents blood from flowing back into the ventricles whenthey relax?

A: The human heart is situated in the middle of the thoracic cavity in a space called the mediastinum.…

Q: Draw a labeled cardiac muscle action potential.

A: Introduction: A cardiac muscle action potential is a brief change in voltage across the cell…

Q: How does the excitation-contraction coupling in skeletal muscles and in cardiac muscles differ?

A: Introduction: The excitation/ depolarization of the muscle fiber results in developing action…

Q: Why can we say that cardiac muscle contraction is graded?

A: Cardiac muscle contraction refers to the contraction occurring within the cardiac muscles of the…

Q: How does digitalis result in an increased contractile force of cardiac muscle?

A: The muscular system consists of three types- Smooth muscle Skeletal muscle Cardiac muscle Cardiac…

Q: In the nineteenth century, Poiseuille’s law was experimentally deduced byJ. L. M. Poiseuille, who…

A: There are few primary assumptions for the validity of Poiseuille’s Law. Whenever one assumption…

Q: How does the barorecptor reflex explain the decrease in heart rate during carotid sinus massage?

A: The carotid sinus and aortic arch contain baroreceptors, which are mechanoreceptors. Their job is to…

Q: If SA node (=natural pacemaker) fıring rate is 100 potentials per minute, but resting heart rate of…

A: Introduction: Some cardiac tissues are concerned with the initiation (impulse generation), and…

Q: How does a positive inotropic agent increase the strength of cardiac muscle contraction?

A: A positive inotropic agent is any drug or medication that can change the force of contraction with…

Q: How is long refractory period beneficial for cardiac muscles?

A: Introduction: The heart is a muscular beating organ that transports deoxygenated blood to the lungs…

Q: A drug is found to partially inactivate fast sodium channels. Mow would this drug change the action…

A: Given: To find a drug that partially inactivate fast sodium channels. How it change the action…

Q: Acetylcholine affects the graded potential of autorhythmic cells

A: Introduction: Autorhythmic cells: The myocardial conducting cells have the ability to originate the…

Q: In a cardiac contractile cell what is the mechanism involved in the change in membrane potential?…

A: The cardiac contractile cell undergoes various changes in order to perform several activities and…

Q: What effect would stimulating the acetylcholine receptors of the heart have on cardiac output?

A: The heart is the primary muscular organ of the cardiovascular system that is responsible for pumping…

Q: release of --------- onto skeletal muscle blood vessles result in ...... 1. Acetylcholine,…

A: Hi, as per our authoring guidelines, we can only answer the first question. Please post the rest of…

Q: Describe the structure of intercalated discs in cardiac musclecells, and briefly discuss their…

A: Cardiac muscle tissues are tissues of the heart and help to provide strength and flexibility from…

Q: What effect does sympathetic stimulation have on stroke volume if thevenous return remains constant?…

A: Most blood vessels, including those in the skin, the digestive tract, and the kidneys, constrict…

Q: Why, in physiological terms, does systolic blood pressure increase from rest to exercise and why…

A: Introduction: Metabolic requirements of the body at rest or during exercise are met by supplying…