Nervous system and Integumentary System (skin)

The Nervous System The nervous system is the control center of the body; it interprets the senses and enables you to respond Smell, taste, touch, sight, and sound are controlled by this system This system receives messages from inside and outside the body and transmits instructions about how to respond

The Main Parts The Central Nervous system- contains the brain and the spinal cord. The Brain- the control center of the nervous system. It receives messages, interprets them and sends messages though the nervous system on how to respond Spinal Cord- composed of many nerves that links the brain to most of the nerves in your peripheral nervous system Peripheral nervous system- includes all of the nerves located outside the central nervous system

How do those nerves send messages? Neurons- cells that carry information through the nervous system. Nerve impulse- the message that neurons carry The 3 kinds of neurons Sensory neuron- picks up stimuli from the environment and converts it into a nerve impulse Interneuron- carries the nerve impulse from one neuron to the next Motor neuron- sends an impulse to a muscle or gland, which will then react to the message

How messages travel First the sensory neuron picks up the message The interneuron passes the message along to the brain which interprets it and sends a response back to the interneurons. The motor neurons pick up the message and respond with the action needed

Things to know about the nervous system A neuron (nerve cell) is the basic unit of structure and function of the nervous system. A response that is made automatically is a reflex. Your spinal cord is made of bundles of neurons that carry impulses from all parts of the body to the brain and from the brain to all parts of your body. The spinal cord is about as big around as an adult thumb and 43 cm long. Your eyes, ears, tongue and nose are also key parts to this system, since they will send messages to your brain as well. Nervous system review

Integumentary System (skin) Purpose: Your skin covers and protects the body from injury, infection, and water loss. It also regulates body temperature eliminates waste, gathers information about environment and produces vitamin D. Main parts Epidermis- top of 2 main layers of skin it does not have nerves or blood vessels Contains melanin a pigment that colors the skin and protects from burning. Dermis- thin inner layer between the epidermis and fat (this fat layer helps keep heat in the body) Pores- holes in skin that allow sweat to reach the surface. Follicles- structures that allow hair to grow (hair above the surface of skin is made up of dead skin cells). Oil is produced here too, that oil waterproofs hair and keeps skin moist and healthy.

How skin does what it does! Protecting the body- forms a barrier that keeps disease-causing microorganisms outside the body. It also keeps water in your system, just like how plastic wrap it keeps food from drying out. Maintains temperature- by letting you sweat when you overheat and increasing blood flow when hot. This lets heat escape from the body. Eliminating waste- Perspiration contains waste materials, so when you sweat, more of that waste can leave the body Gathering information- the nerves in your skin provide information such as pressure, pain, and temperature. This information warns you if something in the environment is hurting you Produces Vitamin D- your skin cells can produce vitamin D which helps your digestive system absorb calcium which your bones need. You only need a few minutes in the sun to make all the vitamin D you need in one day. Skin review