Smooth muscle founded in the gastrointestinal tract of the Northern leopard frog, Rana pipiens, contracts through myogenic activity. However, neurotransmitters from the parasympathetic and the sympathetic branches of the autonomic nervous can influence the strength of these myogenic contractions. To explore myogenic activity under the influence of the autonomic control, we examined the contractile activity with and without additions of chemical compounds associated with the autonomic nervous system. We also wanted to observe contractile activity under the influence of mechanical stimulus by manually stretching the gastrointestinal smooth muscle. With the addition of acetylcholine and eserine a significant increase in contraction amplitude and …show more content…
The addition of acetylcholine caused a significant increase in contraction amplitude from 0.00983 + 0.00109 N (N=3) to 0.0740 + 0.00807 N (N=3) (Fig. 1). It also caused a significant increase in contraction duration from 17.3 + 1.44 s (N=3) to 47 + 10.5 s (N=3), the maximum duration observed (Fig 3). The second compound added was eseine. The amplitude of these contractions significantly increased to 0.117 + 0.0126 N (N=3), the maximum amplitude observed (Fig. 1). The frequency of contractions also significantly increased from 1.67 + 0.577 (N=3) to 3 + 0 (N=3), the maximum frequency observed (Fig. 2). Moreover, contraction duration significantly increased to 41.8 + 5.01 s (N=3) when compared to the baseline (Fig. 3). There was a third and fourth treatment that added the chemical compounds atropine and epinephrine respectively, but due to the flat lining of the gastrointestinal smooth muscle, measurements were not obtained. After the manual stretch of the gastrointestinal smooth muscle only one contraction was observed. The amplitude of these stretches decreased to 0.00167 + 0.000404 N (N=3), the minimum amplitude observed
The purpose of this study was to compare contractility of individual preparations glycerinated rabbit psoas muscle exposed to two different solutions known to cause muscle contraction. A standard contracting solution without 15 mM of creatine phosphate and a second contracting solution with 15 mM of creatine phosphate were compared to one another. Creatine phosphate has been found as
Table 5. The effects of Atropine measured by the ventricle of the frog’s heart by amplitude, period, and BPMs.
Smooth muscle contraction occurs when calcium is present in the smooth muscle cell and binds onto calmodulin to activate myosin light chain kinase (Wilson et al., 2002). Phosphorylation of myosin light chains result in myosin ATPase activity thus cross-bridge cycling occurs causing the muscle to contract (Horowitz et al., 1996). There are two known models of excitation and contraction in smooth muscle, electromechanical coupling (EMC) and pharmomechanical coupling
Acetylcholine is found at the peripheral nervous system and synapses in the central nervous system within the human body. Acetylcholine is an excitatory neurotransmitter that conducts electrical impulses, allowing nerve cells to communicate with muscle cells and generate muscle contractions. However, acetylcholine produces an inhibitory effect in cardiac muscle. (Waymire, 1997) Therefore, once the Daphnia are exposed to acetylcholine, their heart rate is expected to decline. In contrast, epinephrine, also known as adrenaline, is a hormone which binds to the beta adrenergic receptors in the heart leading to increases in the firing rate of the pacemaker cells. (Meyers, 2011) Therefore, the Daphnia’s heart rate is expected to increase with exposure to
Contractility of ASM requires an increased levels of intracellular Ca2+. When surface receptors are not activated, Ca2+ levels are low. Upon activation of these cell surface receptors by contractile agonists e.g. acetylcholine, serotonin and histamine, intracellular Ca2+ increases causing a contraction (9). Smooth muscle cell contraction is controlled by both receptor and mechanical activation of proteins actin and myosin and also changes to membrane potential.
These muscle tissue cells specialised to contract and move parts of the body. It is also capable of responding to stimuli. There are three types of muscle in the body such as: skeletal, cardiac and smooth. Each muscle is created of muscle fibers that are capable of contracting and returning back to original state-relaxation. Contraction causes movement of the skeleton, soft tissue, blood or specific material. Skeletal muscle is attached to the bones of the skeleton. Some facial muscles are attached to the skin. They have direct control over them through nervous impulses from our brain sending messages to the muscle. Contractions can vary to produce fast, powerful movements. These muscles also have the ability to stretch and contract to return to original shape. Cardiac muscles are found in the chambers of the heart such as the atria and ventricles. It is under the control of the automatic nervous system; however, even without nervous input contractions can occur. It is completely different to all the other muscles. Smooth muscles are also known as involuntary due to our inability to control its movement. This muscle is usually found in the walls of hollow organs
Mechanical and electrical activity was monitored in a frog heart as it was subjected to various changes in temperature, stretch, and differing drugs. In separate procedures, heart rate and contractile force were observed by applying various temperatures of Frog Ringer's solutions to the heart, increasing degrees of stretch, and administering various drug treatments of Acetylcholine, Epinephrine, Pilocarpine, and Atropine. Results show that Increasing temperature of the Frog Ringer's resulted in an increase in heart rate. An increase degree of stretch resulted in an increase of contractile force. Acetylcholine and Pilocarpine slowed the heart rate when they were applied. Conversely, the addition of Epinephrine and Atropine + Acetylcholine increased
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
Szent-Gyorgyi discovered that contraction occurs in the presence of adenosine triphosphate (ATP) and KCI. The rate of the contraction is capable of increasing by the presence of MgCI2. [1] KCI consists of salt, which is capable of causing muscles to contract in considerable dosages. The dosage given to the rabbit muscle was a fairly adequate amount, resulting in the muscle contraction of muscle strand #2 (which received treatment B). The MgCI2, also known as magnesium chloride solution, is used frequently as a ready-to-go reaction mixture to increase the reaction of experiments and lab studies.
Albuterol acts on beta2-adrenergic receptors located in the smooth muscle of respiratory tract. Activation of beta-2 receptors results in subsequent increase in adenyl cyclase and cyclic AMP. Increase in cyclic AMP leads to the activation of protein kinase A, inhibiting phosphorylation of myosin, thereby lowering intracellular ionic calcium concentrations, resulting in relaxation of the smooth muscle
Once stimulated by the chemoreceptor trigger zone, the integrative vomiting centre coordinates the activation of all the nearby neural structures required to produce the multifaceted patterned response that will then lead to the processing and action of vomiting. The integrative vomiting centre coordinates the various inputs to the motor component of the emetic reflex, consisting of both somatic and autonomic systems, as the reflex involves both voluntary and involuntary processes. The abdominal and respiratory musculature, and visceral components involved in mediating changes in gastric motility and gastric tone are controlled by somatic pathways, while the autonomic pathways control sweating, salivation and pallidity of the skin. The activation of autonomic pathways plays a role in the intensity and duration of the nausea that accompanies emesis, as opposed to the actual action of vomiting (myVMC,
The food enlarges the abdomen and this presses on the flat diaphragm. The muscle is inhibited from participating in
Discussion The experimenters began their analysis of the data by considering the general trends of the length-tension relationship for the frog heart. The experimenter noted that the increase in length of the ventricle led to an increase in active force generation, an increase in total force generation, and an increase in the development rate for all of the conditions. The experimenters also noted that increasing the ventricle length increase the relaxation rate for the isoproterenol and KCl trials but had an inconclusive effect on the relaxation rate for the baseline trial. Physiologically, these results are reasonable because the heart sarcomeres are designed differently than the skeletal muscles, in that, the heart sarcomeres have an associated
A decrease in stimulus frequency results in a greater number of contractions within the ileum. An increase
Where do you think the world would be without the major development of horror and detective genres? The one person that included majorly in the push towards evolving the growth of the horror and detective genre based stories we have come to love is from Edgar Allan Poe. Born in January 19, 1809 and later dying in October 7, 1849 Edgar Allan Poe spent most his life indulged in bad happenings such as his loved ones including his mom dying from tuberculosis. Continuing in the future he started to wright and produce short stories in the horror and detective. He furthered the investment of people’s minds into the new set of horror and detective story genres by the influence of his books, that inspired many to become great writers in the future.