Pycnopodia's Nervous System

The nervous system is made up of 2 main parts - the spinal cord and the brain. These two parts combine to make the central nervous system and the sensory and motor nerves which form the peripheral nervous system. Neurons process information in the form of electrical signals, namely nerve impulses, which travel along the axon. Charged ions are not able to enter plasma membranes which make neurons have a difference in ion concentration between the inside and the outside of a neuron. This prevents the passive diffusion of Potassium and Sodium ions from areas of high concentration to areas of low concentration. Proteins which act as ion channels and ion pumps are attached to plasma membranes. This allows the ions to be transported across

What are the sensory components of this structure? What are the motor components of this structure?

The nervous system of cnidarians is called a nerve net. This is the simplest nervous system found in any organism (The Nervous System: Organization). It is called a nerve net because there is no center point of the system, and the nerve cells are spread throughout the body in a net like system (The Nervous System: Organization).

Carry messages from special receptors in the skin, muscles, and other internal and external sense organs to the spinal cord, which sends them to the brain

A series of Laila’s sensory nerves receive external stimuli

Our focus for this week’s lab was the vertebrate nervous system. The nervous system is composed of two divisions called the central nervous system and the peripheral nervous system. Within these two divisions there are three types of neurons that allow us to recognize changes in our environment and help us to respond accordingly. The three neurons that are found are called sensory neurons, interneurons, and motor neurons.

The CNS contains the brain and spinal cord. Its main functions include: processing, integrating, and coordinating sensory information and motor instructions. The sensory data conducts information that is being processed from internal and external conditions the body is experiencing. Motor commands regulate and control peripheral organs (skeletal muscles). The brain functions under memory, emotions, learning, and intelligence. The PNS consist of the neural tissue found outside of the CNS. It functions in sending data to the CNS which motor commands are than carried out to the peripheral tissues/systems. Multiple nerve fibers send sensory data and motor commands in the PNS. The nerves that assist with transmitting data include the cranial nerves and spinal nerve. However, the PNS can be divided into afferent (to bring in) and efferent (to bring out) divisions of transferring data. The afferent division functions in bringing in sensory data to the CNS. Sensory structures are receptors that detect internal/external environmental change and adjusting accordingly. The efferent division functions in carrying out motor commands from the CNS to glands, muscles, and adipose tissue. The efferent division contains somatic

In order to make the proper patterns from the visual signal, the octopi create chromatic patterns through the use of chromatophores in the skin. A chromoatophore is a pigment cell surrounded by muscle fibers found below the skin. The pigments in cephalopod chromatophores commonly include yellow, red, and brown. The chromatophore lobes in the octopus brain control the muscle fibers. Through electrical coupling between the muscle fibers and phasic and tonic contractions, the chromatophores are able to adjust the pigment in the skin (Boyle and Dubas, 1985). In addition to chromatophores are iridophores and leucophores. Iridophores reflect short wavelength colors in contrast to the long wavelength colors of the chromatophores. Due to iridophores, octopi are able to perceive white polarized light giving them an advantage against their predators. On the other hand, leucophores diffuse ambient light and allow for dark pigmentation. In addition to the pigmentation, octopi are able to change the texture of their skin through the use of papillae in the skin. Through the ability to change the skin pigmentation by the constriction of chromatophores and activation of both iridophores and leucophores, octopi are equipped to change their pigmentation to match their visual field. When posed with an environment with distinct structure and

The peripheral system relays information to and from the central nervous system and enables detection of sensation in the legs, under the sensory division. The ability to detect sensations outside the central nervous system is enabled by the peripheral nervous system; it consists of bundles of nerves/axons that allow the body to detect sensation. The axons involved are connected to the brain and the spinal cord; the spinal nerves carry information to and from the spinal cord and cranial nerves carry information to and from the brain. The sensory division of the system consists of axons that communicate information from the sensory receptors; the sensory receptors used to detect sensation in our legs are somatic sensory neurons, which are the neurons that detect sensation in the external environment. The neural pathways involved in detecting general sensations are somatosensory pathways; these pathways relay information from the skin, tendons, musculature and joints. The pathway is afferent, information if sent from the periphery to the brain; from the periphery, the first order neuron travels and enters the spinal cord through the dorsal root, before synapsing in the posterior dorsal grey horn, the second order neuron then travels through the ascending white matter tracts and synapses in the thalamus, the third order neuron terminates when it reaches the primary

When you are trying to escape from the danger, the sympathetic nervous system is active that makes your heart beats faster and starts sweating. After the danger passed the parasympathetic nervous system will prepare the body for rest. All the materials that I learned from the lectures and homework are really helpful to me. Now I understand how my brain works and what is the structure of the brains and what are they

Cnidarians do not have a central nervous system (no local concentration of nerve cells, no brain), but the anemones simple differentiated nervous system works much the same. Arrangements of nerve cells within a loose network called nerve nets process and respond to stimuli much like a brain would. For example, in response to stimuli, nerve cells emit electrical impulses through the nerve net to all parts of the anemone’s body, causing contractions in the anemone’s muscles. The result is movement.

The shape is cuticle-covered appendages that contain approximately 120 and 1200 olfactory receptors neurons (Wellerdieck et al., 1997; Zhao et al., 1998).

This essay will describe the structure and function of the nervous and muscular systems and examine Spinal Muscular Atrophy (SMA), discussing the affect the disease has on these systems. Particular attention will be paid to Type I SMA. This will be done by analysing a range of sources in order to gain a clear understanding of SMA and the nervous and muscular systems.

The nervous system in a canine is made up of these three things: Brain, spinal cord and several different kinds of nerves located throughout the body. They create complex circuits through which animals experience and respond to sensations: The central nervous system includes the spinal cord and brain. The brain has three main sections: the brain stem that controls several basic life functions. The cerebrum, which is the center of conscious decision making, and lastly, the cerebellum which involves movement and motor skills in the animal. The most common type of nervous system circuit that most people are familiar with is the reflex. Reflexes are simple networks found in the nervous system of all animals. For example, if a dog goes down in

Cockroach femoral tactile spine is a type I mechanoreceptors and it contains a single bipolar sensory neuron. At the base of the tactile spine, there are afferent neural sensory dendrites which are sensitive to signals. These dendrite in the wall of the spine leads through the spine lumen to a cell body, and then to an axon that proceeds along the femur. One interesting point is that the cell body is surrounded by glial cell however there is no glial cell wrapped around axon body or dendrites. The location of glial wrapping can suggest that they assist in passive conduction action potential from dendrites to the axon. (French 1993).