1. Notes Ch. 10a Nervous System 1
Anatomy and Physiology

2. Overview of the Nervous System
The nervous system oversees all that we do and determines who we are. The nervous system sends and receives changes that affect the body.
The nervous system is made of neural tissue, but also blood vessels and connective tissue.
Neural tissue is made of 2 types of cells: nerve cells (neurons) and neuroglia.

3. Neurons are specialized to react to physical and chemical changes in their surroundings.
Dendrites are small cellular processes that receive input.
A longer process called an axon (nerve fiber) carries the information away from the cell in the from of bioelectric signals called impulses, this allows the neuron to communicate with other neurons and with cells outside the nervous system.

4. Generally axons are grouped together
Generally axons are grouped together. In the peripheral nervous system bundles of axons are called nerves. In the central nervous system (brain and spinal cord) are called tracts.
Neuroglia are found throughout the nervous system, and in the brain they outnumber neurons. Neuroglia are important for nourishing neurons and sending and receiving chemical messages.
Neuroglia are grouped in special, protective ways in the brain.

5. Cells that form capillaries in the brain are tightly connected are neuroglia called astrocytes. This is important in the brain to provide a shield for the brain from chemical fluctuations.
An important part of the nervous system is the small space between a neuron and the cell(s) that it communicates with, called a synapse.
Neurotransmitter are biological messenger molecules that relay information.

6. There are 2 main groups in the nervous system:
The central nervous system (CNS) is made of the brain and spinal cord.
The peripheral nervous system (PNS) is made of nerves that connect the central nervous system to other body parts.

7. General Functions of the Nervous System
There are 3 general functions of the nervous system - receiving information, deciding what to do , and acting on those decisions - they are called sensory, integrative, and motor.
Sensory receptors at the end of neurons in the PNS provide sensory functions. They gather information by detecting changes inside and outside the body. They monitor external environmental factors like light and sound intensities, temperature, oxygen concentration, and other conditions of the body’s internal environment.

8. Neurons that conduct impulses from the CNS to responsive structures called effectors carry out the motor functions of the nervous system. These are muscles and glands.
The motor part of the PNS is subdivided into the somatic nervous system (voluntary part) and the autonomic nervous system (controls involuntary unconscious actions like the heart and certain glands).