Introduction to the physiological system to be discussed
Sensory systems are essential to a mammal’s survival and for providing important information concerning their internal and external environment (Hill et al., 2011). Sensory systems depend on specialized sensory receptor cells that respond to stimuli, either from the mammals’ internal or external environment (2011). One form of sensory is electroreception, which is the detection of electrical currents or fields in aquatic mammals and mechanoreceptors are specialized to respond to different types of mechanical stimuli, such as touch, taste, smell, etc. (2011). The platypus (Ornithorhynchus anatinus) exhibits electroreception with the help of mechanoreceptors to detect prey item while submerged in water.
In general, electroreceptive fishes are categorized into non-electric fishes and electric fishes (Crampton & Albert, 2005). On the one hand, non-electric fish do not possess electric organs and use passive electroreception, which is when the fish reacts to external electric stimuli (2005). On the other hand, electric fish are fishes that have specialized electric organs (electrosensory organs) present and use active electroreception, which produce or generate electrical stimuli (2005). The receptors that electric or non-electric fishes use to detect the electrical stimuli are called pit organs that are often open to the surrounding water by way of canals that are filled with an electrically conductive gelatinous substance (2005). There are two types of pit organs: tuberous electroreceptive organ, which are used in active electroreception, and ampullary electroreceptive organ, which is used in passive electroreception.
The tuberous electreceptive organ is covered wi...
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...regions of the fish, there are electroreceivers that detect distortions in the electric field (1993). The arrangements of the electrocytes are important because it allows the gymnotid to detect what’s ahead and then use its tail to produce a charge. If electroreceivers were in the tail region, the mammal would detect electric signals a lot slower. In ion-poor waters, like freshwater, allows the gymnotid to generate electric signals because little current is needed to sustain a detectable voltage (Stoddard, 2009).
Gymnotids have tuberous electroreceptors that have numerous layers of epithelial, which allows for low capacitance. This means the electroreceptor has a low ability to store electrical charge, which is beneficial because the mammal wants to discharge the electricity and the mammal would not want the electroreceptor to be good at holding the electricity in.
Barlow (1953) first postulated the existence of feature-sensitive ganglion cells in a frog’s retina based on an inhibitory-surround structure of the receptive field. He maintained that the “on-off” units of these cells triggered by the presence of a particular stimulus corresponded to certain behaviour in the frog. For example, presenting a spot of light in the visual field would cause certain neurons to fire in a particular ganglion cell, and in a live frog, would cause the frog to snap at the stimulus. Barlow concluded that these cells must be “fly detectors”. Lettvin et al. (1959) further examined the visual mechanisms of the frog and discerned fo...
The nerve itself is composed of a cell body (called a soma), an axon, and dendrites. Nerves send signals using an electrical charge that is passed from the dendrites,to the axon, then to the next cell. This electrical signal, known as a nerve impulse, is created by the movement of ions. Sodium (Na+) ions migrate into the nerve cell because of stimulation from the central nervous system. This creates a net localized positive charge inside the cell, called an action potential. However, the positive charge degrades as it moves through the cell because the ions will diffuse (and then so will the local charge). The nerve cell has devised a mechanism to keep the magnitude of the charge it receives and then later transmits at a constant value.
Dingle H, Fox SS (1966) Microelectrode Analysis of Light Responses in the Brain of the Cricket (Gryllus &mes~icus). J. cell physiology... 68: 45-60
The brain is part of the central nervous system, which consists of neurons and glia. Neurons which are the excitable nerve cells of the nervous system that conduct electrical impulses, or signals, that serve as communication between the brain, sensory receptors, muscles, and spinal cord. In order to achieve rapid communication over a long distance, neurons have developed a special ability for sending electrical signals, called action potentials, along axons. The way in which the cell body of a neuron communicates with its own terminals via the axon is called conduction. In order for conduction to occur, an action potential which is an electrical signal that occurs in a neuron due to ions moving across the neuronal membrane which results in depolarization of a neuron, is to be generated near the cell body area of the axon. Wh...
The neuron has two important structures called the dendrite and axon, also called nerve fibers. The dendrites are like tentacles that sprout from the cell and the axon is one long extension of the cell. The dendrites receive signals from other neurons, while the axon sends impulses to other neurons. Axons can extend to more than a meter long. Average sized neurons have hundreds of dendrites; therefore it can receive thousands of signals simultaneously from other neurons. The neuron sends impulses by connection the axon to the dendrites of another nerve cell. The synapse is a gap between the axon and the adjacent neuron, which is where data is transmitted from one neuron to another. The neuron is negatively charged and it bathes in fluids that contain positively charged potassium and sodium ions. The membrane of the neuron holds negatively charged protein molecules. The neuron has pores called ion channels to allow sodium ions to pass into the membrane, but prevent the protein molecules from escaping (potassium ions can freely pass through the membrane since the ion channels mostly restrict sodium ions). When a neuron is stimulated (not at rest), the pores open and the sodium ions rush in because of its attraction to the negatively charged protein molecules, which makes the cell positively charged. As a result, potential energy is released and the neurons send electrical impulses through the axon until the impulse reaches the synapse of any neurons near it.
The most unique feature of the platypus is the soft and pliable bill. The bill surface is perforated with openings that contain nerve endings, which allow the animal to locate food and aid movement under water. These pores contain two types of sensory receptors: mechanoreceptors, which respond to tactile pressure, and electroreceptors, which respond to electric fields. The eyes and ear openings are located behind the bill in a muscular groove, which contracts and closes as the platypus dives (Griffiths, 1998). The nostrils are positioned towards the tip of the bill and are slightly elevated upwards to allow breathing whilst the body is beneath the surface (Figure 1).
Nerve cells generate electrical signals to transmit information. Neurons are not necessarily intrinsically great electrical conductors, however, they have evolved specialized mechanisms for propagating signals based on the flow of ions across their membranes.
The discoverer of the titanic, Dr Robert Ballard famously referred to the deep sea as ‘far more alien than going to mars or the moon.’ The deep sea is one of the largest virtually unexplored ecosystems on the planet; it is found at a depth of 1000 fathoms [1] and is subject to adverse changes in temperature, pressure and light penetration amongst other factors. Therefore as expected fish decrease in abundance, and species diversity. This trend is prominent as in order to survive the harsh conditions of the deep sea, fish need a number of specific adaptations. Allowing them to ultimately survive, feed, and reproduce.
Piatigorsky, Z., Kozmik. 2004.Cubozoan jellyfish: an Evo/Devo model for eyes and other sensory systems. Int J Dev Biol 48: 719–729
• You need to know that fish has senses. They can hear, taste, see, and smell. They have lateral line which helps them to detect movement in water. When they are in danger, they can run away. You will really have to watch your movements because you do not want to go away with empty hands.
With the addition of sharks anatomy, they have quite complex body parts than compared to simple bony fish, which can show a lot about the characteristics of sharks. Starting with gills, sharks "contain five to seven slits of gills on each side of their head" ("Shark Anatomy") all serving an important purpose for them to live. When the water goes through their gills the oxygen is absorbed by the blood in the gills and they move throughout towards the rest of the body. Since larger sharks contain more slits of gills for their bodies than compared to smaller sharks the body has to work less to oxidant the body. In the internal bodies, there are "electro receptive organs which are called Ampullaes, which are jelly-filled pores shaped like clay jars used by the Romans to ...
The way that each individual interprets, retrieves, and responds to the information in the world that surrounds you is known as perception. It is a personal way of creating opinions about others and ourselves in everyday life and being able to recognize it under various conditions. Each person’s perceptions are used as a kind of filter that every piece of information has to pass through before it determines the effect that it has or will have on the person from the stimulus. It is convincing to believe that we create multiple perceptions about different situations and objects each day. Perceptions reflect our opinions in many ways. The quality of a person’s perceptions is very important and can affect the response that is given through different situations. Perception is often deceived as reality. “Through perception, people process information inputs into responses involving feelings and action.” (Schermerhorn, et al.; p. 3). Perception can be influenced by a person’s personality, values, or experiences which, in turn, can play little role in reality. People make sense of the world that they perceive because the visual system makes practical explanations of the information that the eyes pick up.
Marine organisms continue to amaze scientists with their physiological adaptations that allow them to live and thrive in the largest unexplored habitat known to man. Carl Zimmer argues that “most fish without lungs die” because “lungless fish pump their blood in a simple loop.” Therefore, fish are restrained by a lack of oxygenated blood flow that the heart can receive and will die if they exercise too hard because the heart simply won’t receive enough oxygen to sustain intense exercise. In order to solve this problem many species of teleosts and chondrichthyes possess adaptations that allow them to continue exercising at extremely high speeds without necessarily dying. Tunas, for example, are pelagic thunniform swimmers that have evolved these special adaptations that allow them to maintain high cruising speeds and high metabolic rates. They possess special adaptations in muscle, cardiovascular, and respiratory physiology that set them apart from many other species of teleosts.
Convergent evolution explains the similarity in body structure of the swordfish and dolphins, where two different organisms that are not closely related, independently evolved similar structures. Subjected to the similar aquatic environment and similar challenges, the swordfish and dolphins developed a similar body structure, a streamlined body (Figure 12; Baltimore, 2002). The streamlined body is the body structure that is broad in the middle and narrow at both ends. The development of the streamlined body is an advantageous structure to living in an aquatic environment. The streamlined body made it more efficient for locomotion, by reducing water resistance, thus increasing the efficiency of swimming for marine animals and for the vertebrates’
The five senses of sight, hearing, touch, taste and smell are all sensations throughout the human body. Sensation is the involvement of sensory receptors as well as the central nervous system in order to allow us to experience outside stimuli. The system that allows us to experience sensation is the sensory system.