INTRODUCTION
Within vertebrates, heart rate is established by the sinoatrial (SA) node of the heart. This is achieved through a series of action potentials which drives excitation of cardiac muscles and establishes a rhythmic pace (Fritz et al., 2011). However, there are numerous factors that can affect the SA nodes impact on heart rate, which are primarily related to the autonomic nervous system.
The autonomic nervous system is responsible for the regulation of involuntary functions, and is broken up into the parasympathetic (PSNS) and sympathetic nervous systems (SNS). The SNS is most commonly referred to as an organism’s ‘fight or flight’ response, in which its activation is generally in response to stress, and results in a preparation
The central nervous system is composed of the brain and spinal cord and the peripheral nervous system is composed of the body’s sensory receptors, muscles, and glands. The peripheral nervous system is made up of somatic and automatic. Somatic is the voluntary movement of our skeletal muscles. When we hear the bell ring, our somatic nervous system carries the message to the brain and the brain reports back to our muscles. The autonomic nervous system controls our glands and muscles in our internal organs. Some things this nervous system does is taking control of our digestive system and our heart beat. There are two functions of the autonomic nervous system- the sympathetic and the parasympathetic nervous system. The sympathetic nervous system arouses and expands energy. If someone gets excited or nervous in a situation, their blood pressure will rise, their digestion will slow down, their heartbeat will accelerate, their blood sugar will rise, and they will sweat to cool down. The parasympathetic is the opposite. It tries to conserve energy by decreasing your heartbeat, lowering your blood sugar, and so
The heart serves an important purpose within the body, pumping blood throughout the circulatory system to supply all parts of the body with vital nutrients and molecules. It pumps oxygen and nutrient rich blood to be exchanged for carbon dioxide, which is then pumped to the lungs and eliminated from the body. The movement of blood throughout the body is due to the heart’s ability to push blood along the circulatory system at a steady, unfaltering rate. This rate, known as heart rate, is regulated and can be altered at a moment’s notice by signaling within the body and heart itself. In vertebrates, the autonomic nervous system controls and regulates heart rate. The autonomic nervous system is divided into two subunits, the sympathetic nervous system and parasympathetic nervous system. The parasympathetic nerve that innervates the heart is the vagus nerve. In this laboratory experiment, the regulation of heart rate was observed by studying a certain breed of turtle, the Red-eared Slider (Trachemys scripta elegans). Both chemical and electric signaling can influence the components of the nervous
The SA node is the primary pacemaker of the heart. It starts the heartbeat by spontaneously contracting, causing the rest of the heart to contract in a wave.
The sympathetic nervous system is responsible for the body in times of stress and activates the “fight or
This allows your cardiovascular centres in your brain a little bit more latitude as far as controlling your heart rate. If you were to remove a beating heart from someone's body you would find that the heart is no longer being suppressed by the parasympathetic nervous system and it will accelerate to the same pace as the sinoatrial node. The SA node generates action potentials approximately 100 times per minute due to the physiology of the heart, its own permeability to sodium and calcium via its channels, and a host of other things. Anywhere between 80 to 100 beats per minute is normal for the SA node.
Conclusively, the SA node controls heart rate, and also sends signals through the heart, to the AV node, down to the AV bundle and up on the purkinje fibers which spread the signal through the ventricles. The EKG scan is used to show the heart rate, and how the heart is functioning at that moment. There are multiple letters involved in this - P, QRS, T, and sometimes
After completing a lengthy test or a job interview, your parasympathetic nervous system kicks in and regulates the relaxation or “rest and digest” response. It increases flow in digestion, constricts the pupil, relaxes the muscles, and lowers the heart rate. It uses cranial nerves from the CNS to operate these
SA node: The sinoatrial node is a section of nodal tissue located in the upper wall of the right atrium. Sets the rate of contraction for the heart. Spontaneously contracts and generates nerve impulses that travel throughout the heart wall causing both
The Sympathetic and Parasympathetic nervous systems work in opposition to each other, The Sympathetic system prepares the body for action whereas when the stressful situation is over the parasympathetic system returns the body back to normal.
The pacemaker of the heart, the sinoatrial (SA) node, generates the impulses that trigger the contractions of the heart chambers. In a very sequential, coordinated rhythm at a rate of 75 times per minute, it depolarizes faster than the other pacemaker cells of the heart preceding them with their impulses. Located in the superior right atrium, these spontaneously depolarizing myocytes trigger a depolarization wave, via gap junctions, to the left atrium and the atrioventricular (AV) node, lying in the inferior right atrium. Gap junctions, in the intercalated discs, allow the rapid transmission of ions to adjoining myocytes. Furthermore, the electrical signal can conduct through the adjoining myocytes, allowing it to operate as one functional
The sinoatrial node initiates contraction of the cardiace muscle and acts as a pacemaker, regulating normal sinus rhythm
The first stage of shock the underlying disorder, such as a trauma, triggers a decrease in circulating blood volume resulting in hypotension (low blood pressure). The sympathetic nervous system (SNS) is quickly stimulated to try to compensate for the decrease in blood pressure. The signs caused by this stimulation include thirst, anxiety, restlessness, and tachycardia. There are also signs caused directly from the decrease in blood pressure and blood flow. These include dizziness, fainting, fatigue, and lack of
The Parasympathetic nervous system is an antagonist to the sympathetic nervous system. Its primary function is to give you the ability to rest and relax, in times when you are tired or stressed. The parasympathetic nervous system works to save energy and allow your blood pressure to also decrease. Your heartbeat reduces becoming much slower, and digestion can start. Notice again in figure
Medications used for nervous system disorders such as: ADHD, Schizophrenia, Bipolar Disorder and more have been used for years to treat these disorders and others. Most medications have a positive effect on a person, when used correctly and with the right body chemistry. Other times, these medications can cause more harm than good.
In contrast, during aversive situations in which an active coping response is not available, mammals may engage in a vigilance response that involves sympathetic nervous system (SNS) arousal accompanied by an active inhibition of movement and shunting of blood away from the periphery (Adams et al.