Your nervous system is broken down into two separate parts Your (CNS) or Central Nervous System And your (PNS) Peripheral Nervous System Your Spinal Cord and Brain The cordinator and decision maker All of the nerves and wiring (sends messages from your brain to the rest of your body) Sending sensory input and causing motor output There is an Automatic Nervous System (ANS) shares nerves with Both PNS and CNS ( Automatic responses such as blood pressure)
Neurons - Specialized cells that make up the nervous system. They carry information around the body in the form of an electrical or chemical signal Your nervous system regulates and coordinates the actions and activities of your body in response to internal and external environment changes These changes are called stimuli Stimuli initiate impulses in sensory receptors… eyes, ears, nose, tongue, skin, internal sensors Neurons differ from other cells in the body, because they are able To transmit signals from one cell to another in chemical and Electrical form
Brain and Spinal Cord The brain has 100 billion neurons, controls actions, thoughts, and memory The brain weights about 3 pounds and is protected by the Cranium The Spinal Cord is a bundle of nerves that extend from the base of the brain to the bottom of the backbone The Spinal Cord is about 3 foot long and about an inch wide, protected by your vertebra SC controls both voluntary and involuntary actions Cerebrospinal fluid fills the open Space in the brain and spinal Chord (Shock Absorber)
The PNS has 31 pairs of spinal nerves and 12 pairs of cranial nerves In the body Carries nerve impulses to and from the CNS The PNS has two parts… the Somatic and Autonomic systems Somatic = Actions you control (Voluntary) (Skeletal Muscle) Autonomic = Actions you cannot control (Involuntary) (Smooth Muscle) Spinal nerves connect with the spinal cord and innervate most areas Of the body, the cranial nerves connect vital organs directly to the brain
The autonomic nervous system is in connection with our internal organs such as heart, lungs, stomach, and reproductive organs. These organs processes stand above our awareness and are automatically controlled by the nervous system The somatic side of things handles muscles in our extremities and joints. These processes are very much controlled by our own will. The PNS consists of two types of neurons Sensory - runs from stimulus receptor that inform the CNS of the stimuli Motor - runs from the CNS to muscles and glands
There are many different types of Neurons We will discuss two of them Sensory Neurons- Send signals from the sense organ to the spinal cord and brain Motor Neurons- send signals from the brain to the body’s muscles (These are the fastest neurons found in the body) Neurotransmitters- Chemicals that are released at the synapse of a nerve impulse to the target cell or neuron… carry out Communication in the body (Made within the neuron) Some examples of neurotransmitters Are …. Endorphins Acetylcholine Dopamine
Soma - another word for the cell body Nucleus - the brain of the neuron Dendrite - this section of the neuron receives neurotransmitters Axon - the axon terminals send neurotransmitters Synapse - a gap between the axon and dendrite.. Neurotransmitters pass over this. A typical neuron will synapse around 1,000 to 10,000 times during a communication Schwann cells - make myelin, this substance is a fatty insulator that speeds nerve transmission Neurons cannot regrow After damages, except In the Hippocampus… Most neurons stop Reproducing after birth!
Receive message Sends the message Soma Glial cells – Take 3 dif. Forms in the body. Their Main purpose Is to protect and Nourish the Neuron.
BBB (Blood Brain Barrier) - prevents most harmful substances from passing through the blood into the nervous system. The BBB is permeable to Alcohol! There is a special carrier system that allows water, O2, CO2, glucose, and Nutrients to pass through the barrier
Drugs and your Neurons or Nervous System It is now proven that abuse drugs affect the limbic system of the brain (regulates feelings of pleasure) Drugs of abuse produce feelings of pleasure by altering neurotransmission by neurons in the reward system that release the neurotransmitter dopamine Dopamine like other neurotransmitters transfers from one neuron to Another and is then sent back to its source to be used again (reuptake system) When drugs such as crack are used the drug “Clogs” these receptor Sites and creates a dopamine flood creating an uneven and Unhealthy balance of dopamine in your system