The nervous system is the body’s information gather, storage center and control system.
It controls, directs and coordinates body functions.
The nervous system is divided into the central nervous system and the peripheral nervous system.
Identify the structures that make up the nervous system.
Explain how nerve impulses are transmitted.
State the functions of the central nervous system, the peripheral nervous system and the autonomic nervous system.
Identify disorders associated with the nervous system.
Neurons, Nerve Fibers, Nerves and Tracts
Neurons / Nerve Cell
All nervous system tissue is made up of nerve cells, called neurons, and their supporting tissues called neuroglia.
These cells allow the body to interacts with its internal and external environments.
There are 3 types of neurons: motor (doers), sensory (sensors) and interneurons (communicators).
Motor neurons cause muscles to contract and glands to secrete, and organs to perform their functions.
They can also inhibit these actions.
Motor neurons are also known as efferent meaning they carry messages away from the cell body to the muscles and organs.
Motor neurons have a nucleated cell body with process extending away from the cell body.
These nerve fibers are called axons and dendrites.
Dendrites carry impulses to the cell body and the axon carries impulses away from it.
Most axons are covered with a fatty insulating substance called the myelin sheath.
Axons with myelin sheath transmit impulses faster than those without.
Damage to unmyelinated cells is usually permanent.
The axon and dendrites allow neurons to communicate.
What does this mean?
Hit your thumb with a hammer and the motor neurons allow you to pull back you hand.
Smell fresh baked bread and your mouth waters.
Dust in your eye causes you to blink.
The second types of nerve cell is known as the sensory neuron or afferent neurons.
Sensory neurons have sensor receptors that allow transmission or impulses, or messages, to the central nervous system.
Therefore our ability to feel the hammer, smell the bread or feel the discomfort from the dust.
Third type of nerve cell.
Found in the central nervous system and mediate impulses between the motor and sensory neurons.
Nerve fibers, Nerves and Tracts
A nerve is a bundle of nerve fibers, located outside the brain and spinal cord, that connect various parts of the body.
Sensory nerves carry messages to the CNS (brain) and the motor nerves carry messages away from the CNS.
Groups of nerve fibers within the CNS are known as tracts.
Chemical neurotransmitters are stored in the axon terminals.
The space between neurons is called a synapse.
Information is received in the dendrite, passed through the cell body, travels down the axon and over the synapse to the next dendrite.
The Central Nervous System Brain Cerebrum Largest part of the brain Thought intelligence Cerebellum Regulates & Coordinates Body movement Brainstem Connects Cerebrum To spinal cord Spinal Cord Conducts info To & from the brain. Protected by Meninges Dura Matter Arachnoid Pia Matter
The Peripheral Nervous System
The peripheral nervous system has 12 pairs of cranial nerves and 31 pairs of spinal nerves.
Peripheral nerves with special functions for the autonomic nervous system.
The cranial nerves conduct impulses between the brain and the head, neck, chest and abdomen.
Impulses for smell, vision, hearing, pain, touch, temperature and pressure, voluntary and involuntary muscles control.
Peripheral Nervous Stsyem
Spinal nerves carry impulses from skin, extremities and internal body structure not supplied by cranial nerves.
Autonomic Nervous System
Controls involuntary muscles and functions including heartbeat, blood pressure, intestinal contractions and glandular secretions.