Animal Systems: Nervous System. Since you're reading this page, we figure you've got a nervous system. If you were an insect you would also have a nervous system, but it would be a lot simpler. Even animals that don't think have simple nervous systems called nerve nets that help them move. Your nervous system is divided into two parts. Your central nervous system includes your brain and your spinal cord. Your peripheral nervous system is made up of the network of neurons that spans your organs, muscles, and body. The nervous system is about action and senses. The nervous system also senses activity inside of your body. Your nervous system interacts with every other system in your body.
There are many hidden interactions going on within your body. The nervous system is made up of nervous tissues that are, in turn, made up of many types of neurons. Your peripheral nervous system has two types of neurons that are constantly at work. Untitled. Untitled. Untitled. Skin Structure And Function: Definition, Diagrams Epidermis, Dermis Layers: Skin Diseases And Disorders. Diseases And Disorders Of The Skin Diseases and disorders of the skin can be classified under seven categories: 1. Congenital: Exists at birth, may be inherited. 2. Bacterial: Bacteria are single-celled organisms found both inside and outside the body. Some are harmful and others are good for us. Congenital Eczema: Eczema can be found all over the body but most often on the inside of the knee (in the popliteal space) and elbow joints, on the face, hands and scalp.
Bacterial Rosacea: Gives a flushed, reddened appearance. Viral Warts: A small horny tumor found on the skin, often on fingers and thumbs. Fungal Tinea corporis, pedis: Infections which attach themselves to keratinised structures like the skin. Parasitical Infestation Pediculosis: The infestation with lice resulting in severe itching. Pigmentation Disorders Dermatosis Papulosa Nigra: Is a condition of many small, benign skin lesions, characterized by dark-brown papular lesions on the face and upper body, mainly found on a black skin. Skin as sensory organ review2008.
Eye. The Eye [Back to Nervous System] In vertebrates vision begins with light entering the pupil. The cornea and the lens focus and invert the light signal and project it to the back of the eye where the retina is located. The retina consists of several layers of alternating cells and processes that convert the light signal into a neural signal, The Retina [back to top] The retina contains the photoreceptor cells and their associated interneurones and sensory neurones.
A surprising feature of the retina is that it is back-to-front (inverted). Visual Transduction [back to top] Visual transduction is the process by which light initiates a nerve impulse. The detection of light is carried out on the membrane disks in the outer segment. In the dark retinal is in the cis form, but when it absorbs a photon of light it quickly switches to the trans form.
The final result of the bleaching of the rhodopsin in a rod cell is a nerve impulse through a sensory neurone in the optic nerve to the brain. Functions of the Eye. Meaning of Sensory function. What is the function of the sensory system? Six senses are commonly accepted as being accessible to humans and many animals: sight, hearing, taste, smell, touch and proprioception.
That last sense is the ability to know where the parts of the body are in relation to one another at all times. Each sensory organ has nerve receptors attached to it that are designed to transmit signals. For example, the eyes contain photoreceptors for light, the nose and tongue contain chemoreceptors for chemicals, and the skin contains mechanoreceptors for movement, pressure and related sensations. Sensory neurons operate on the all-or-nothing principle; they are either on or off. No varying levels of signal exist. Instead, a stronger stimulus causes more of the receptors to fire or the same amount of receptors to fire more rapidly. When the brain receives sensory input, it sends the appropriate response along motor neuron pathways to respond to the stimulus. Learn more about Nerves.