The ferret SA node is located at the junction of the superior vena cava and right atrium near the sulcus terminalis region (Fig. 1, A and B). Cross sections of the right atrium revealed an ovoid shaped SA node positioned epicardially (Fig. 1C). A light microscopic view of the SA node region shows two nodal arteries, centrally located, surrounded by a ring of dark cells (Fig. 1D). Larger, pale cells form a concentric ring around the dark cells (Fig. 1D). Thus, while being smaller, many features of ferret SA node displayed striking similarities to classic descriptions of human SA node (29; 69; 70). To characterize specific anatomical and functional regions of ferret SA node, we next performed fluorescent in situ hybridization (FISH) to detect (i) cardiac and slow twitch forms of troponin I mRNA (TnIC and TnIS, respectively; Fig. 2, A-D), (ii) cytoskeletal middle neurofilament protein (NF; Fig. 2E) and (iii) growth associated protein 43 (GAP43; Fig. 2F). TnIC has been shown to be the dominant troponin I isoform in atrial myocytes, while TnIS is present in the atrioventricular (AV) node (19). Cytoskeletal middle neurofilament protein (NF) is expressed in the SAN (18; 67; 74). GAP-43 is a marker for neurons (1; 13; 25; 73; 77; 78). Signals generated by antisense probes to TnIS (Fig. 2A) and TnIC (Fig. 2B) show that both transcripts are expressed in our SA nodal sections. TnIS expression was prominent in the central region but minimal to absent in the outer peripheral regions. However, TnIC expression was prominent beyond the central region and minimal to absent in the central region. Overlay of these two transcript expression patterns emphasizes the distinct distribution of cells expressing the two isoforms (Fig. 2C). Fig... ... middle of paper ... ...measure of protein expression. As we have previously shown with Kv1.4, the level of mRNA does not necessarily correlate with protein, although this effect does not seem to be common (10; 51). A second potential issue is that mRNAs detected by FISH may not overlap with protein location within a cell, potentially distorting channel distribution in large distended cells. To ascertain whether this might be the case for channels in the SA node, we performed immunolocalization of several K+ channels (Fig. 8). As is true in ferret ventricles (10), Kv1.4 transcript expression is much greater than the protein expression in the ferret SA node (Fig. 8A). In addition, Kv1.5 transcript expression was also greater than protein expression in the SA node (Fig. 8B). For the other transcripts tested, there are close correlations between transcript and protein (Fig. 8, C-H).
Thyroid and metabolism hormones play a large role in the daily lives of all living species. Thyroid hormones regulate the metabolism and the metabolism is responsible for maintaining a specific range for the biochemical reactions that occur in the body (Martini 2014). The most important hormone for metabolic maintenance is thyroxine (T4). This hormone also plays a large role in body heat regulation. It is produced by the pituitary gland and secreted by the thyroid gland. The thyroid releasing hormone (TRH) must trigger the thyroid stimulating hormones (TSH) to release thyroid hormones to the thyroid gland. These hormones are under control of the hypothalamus, or main neural control center. Propylthiouracil (PTU) is a medication used to treat
When a muscle contracts and relaxes without receiving signals from nerves it is known as myogenic. In the human body, the cardiac muscle is myogenic as this configuration of contractions controls the heartbeat. Within the wall of the right atrium is the sino-atrial node (SAN), which is where the process of the heartbeat begins. It directs consistent waves of electrical activity to the atrial walls, instigating the right and the left atria to contract at the same time. During this stage, the non conducting collagen tissue within the heart prevents the waves of electrical activity from being passed directly from the atria to the ventricles because if this were to happen, it would cause a backflow. Due to this barrier, The waves of electrical energy are directed from the SAN to the atrioventricular node (AVN) which is responsible for transferring the energy to the purkyne fibres in the right and left ventricle walls. Following this, there is a pause before the wave is passed on in order to assure the atria has emptied. After this delay, the walls of the right and left ventricles contract
In this figure, SN = sinus node; AVN = AV node; RA = right atrium; LA
...ape formation, movement of cardiac progenitor cells, heart tube, and heart function. A novel development of more specific assays, advance genetic screen efforts will provide new knowledge on cardiac development in the following years. Additionally, because of the zebrafish distinct features and its similarities to vertebrae, the zebrafish might become many researchers preferred model organism to study many mammal organs. Recently, the zebrafish has been used to study mechanisms that cause human cardiac and liver diseases and to model human hereditary and developed cardiac diseases. Due to the increase in sequencing efforts, the developing interest to study human liver and cardiac diseases. Also, the increase of resource and the more availability of the zebrafish model used in clinical and basic researchers involved in studying the liver, as well as cardiac diseases
The cells of a cardiac muscle are shaped and wider and shorted than a skeletal muscle however they are stripped like skeletal
VanPutte, C., Regan, J., & Russo, A. (2014). Seeley's anatomy & physiology(10th ed.). NEW YORK, NY: MCGRAW-HILL.
problems within the specific ion channels known to cause the disease. The goal of the
Simon, E. J., Reece, J. B., Dickey, J. L. (02/2012). Campbell Essential Biology with Physiology, 4th Edition [VitalSource Bookshelf version 6.2]. Retrieved from http://online.vitalsource.com/books/9781256902089
Imagine if your pet was getting experimented on for a product you might buy in the future. Would anyone really want that product, your pet was in pain because of it? Animals are getting experimented on for products to get released to the public. Some companies are using vitro researching to test their products but not enough companies are using vitro as their form of testing products. Synthetic skin could reduce the amount of animals getting tested on everyday for companies to release new products to the public. Animals are getting experimented on everyday.
This theme song to a popular cartoon is a farce dealing with experiments carried out on animals. In the cartoon one mouse is made very smart and wants to take over the world while the other is clearly not as smart. While the cartoon makes jokes, the reality is that mice and other animals re being used for medical tests every day. For some people this testing brings up ethical questions. One of the biggest questions: is it really necessary to take the lives of animals in the name of science and for the betterment of humanity? For animal rights activists, like People for the Ethical Treatment of Animals (PETA), the answer is no. PETA pressures labs into halting experiments because they believe that animals are not to be used by humans for "food, clothing, entertainment, or to experiment on" (People for the Ethical Treatment of Animals 1). Its stance is that any testing is painful, inhumane, and unnecessary when alternatives are available. The PETA website says that "animals, like humans, have interests that cannot be sacrificed or traded away simply because it might benefit others." (People for the Ethical Treatment of Animals 2-3). Essentially, PETA is of the opinion that animals and humans should have identical rights. In their press releases PETA puts out pictures of rabbits with open flesh wounds and dogs with rashes on their skins--all in an attempt to disgust people into sympathy for their cause. In actuality the number of lab animals used has been cut in half in the last 25 years (James-Enger 254). Of the animals used, 90 percent are rats and mice (James-Enger 1). Moreover, 11 million animals die each year in animal shelters (Americans for Medical Progress 2) and an astounding 95 percent ...
The cardiac cycle is composed of five stages. These stages are atrial systole, early ventricular systole, late ventricular systole, early ventricular diastole, and late ventricular diastole. In order for atrial systole to occur, the blood that has been flowing between the atrium and ventricle via the opened atrioventricular valves must be deposited into the ventricles. The SA node is responsible for the contraction of the atrial myocardium. Once the atrium contracts, blood cannot flow back into or enter the atria because the openings of the great veins has been narrowed by pressure. The ventricles are now filled with blood accomplishing end-diastolic volume which is another term for how much blood your ventricles can contain while your body is at rest. The next phase is early ventricular systole. Now that all the blood is in your ventricles, it must continue onward to the
The heart serves as a powerful function in the human body through two main jobs. It pumps oxygen-rich blood throughout the body and “blood vessels called coronary arteries that carry oxygenated blood straight into the heart muscle” (Katzenstein and Pinã, 2). There are four chambers and valves inside the heart that “help regulate the flow of blood as it travels through the heart’s chambers and out to the lungs and body” (Katzenstein Pinã, 2). Within the heart there is the upper chamber known as the atrium (atria) and the lower chamber known as the ventricles. “The atrium receive blood from the lu...
6. McFadzean I and Gibson A (2002) “The developing relationship between receptor-operated and store-operated calcium channels in smooth muscle”. British Journal of Pharmacology 135: 1-13. Online, available at http://onlinelibrary.wiley.com/doi/10.1038/sj.bjp.0704468/pdf -Accessed 23/11/2013.
Martini, Nath, Bartholomew. (2012). Fundamentals of Anatomy and Physiology Ninth Edition. In N. B. Martini, Fundamentals of Anatomy and Physiology Ninth Edition (pp. Chapter 25; 917-952). San Francisco: Pearson Education.
Most reptiles have ventricles that are mostly separated, but still allow right to left shunting of the blood. Crocodiles have ventricles that are completely separated, but can still shunt blood between the pulmonary and systemic circuits (Axellson, Franklin). This shunting can be completed using the foramen of Panizza, which allows and regulates blood flow from either the left or right ventricle into the left or right aorta. Blood flows from the left ventricle to the right aorta, dorsal aorta, right subclavian artery and the common carotid artery. The right ventricle moves blood into the pulmonary trunk which then separates blood into the left and right pulmonary arteries (Axellson, Franklin). During diving, crocodiles develop a slight bradycardia and develop a right to left shunt once right ventricular pressure rises to a certain threshold. Resting rates of oxygen consumption are maintained and muscular lactate levels do not increase (Grigg). This ability to dive for extended periods of time is made possible by right to left shunting by way of the foramen of Panizza, in addition to the ability to maintain muscular lactate levels. Crocodilian hearts have the ability to keep oxygenated and deoxygenated blood within the heart. Blood pressures are also kept higher in the systemic circuit than the pulmonary circuit (Grigg). These heart adaptations are not seen in other reptiles, but rather in mammalian and avian