Nervous System Flashcards
What are the 3 main functions of the Nervous System?
Sensory function (perception), Information transfer and processing, and Motor function
What makes up the CNS?
Central Nervous System: Brain and Spinal Cord
What are the divisions of the PNS?
Peripheral Nervous System: Sensory (afferent) division and the Motor (efferent) division
What is the function of Sensory nerves?
Sensory (afferent) nerves transmit impulses towards the CNS from the body
What is the function of Motor nerves?
Motor (efferent) nerves transmit impulses from the CNS to the body
What do most Neurons consist of (include how many)?
1 Cell body, many Dendrites and 1 Axon
Describe the cell body
Where the nucleus & other cellular organelles are found
Describe dendrites
The receiving or input portions of a neuron that carry impulses towards the cell body
Describe Axon
Long, thin portion of the neuron which transmits electrical signals from the cell body to the axon terminals. Neurons communicate with each other via chemicals called synaptic bulb ends
How do myelin sheaths affect neurons?
Neurons with axons covered with myelin sheaths can conduct electrical impulses much faster than those that do not.
They also protect nerve cells
How do Nodes of Ranvier affect Neurons?
Nodes of Ranvier assist in the rapid transmission of nerve impulses
i.e. The greater the number of Nodes of Ranvier, the faster the transmission.
How does a Myelinated neurone differ from a non-Myelinated neurone?
A non-Myelinated neurone has a continuous Myelin sheath, there are no Nodes of Ranvier and only one Schwann cell.
A Myelinated neurone will have at least one Node of Ranvier, and is made up of multiple Schwann cells
What is a Schwann cell?
Schwann cells have multiple functions within the PNS.
Importantly, concentric Schwann cells form Myelin sheath
What are Neuroglia?
Non-impulse generating/conducting cells in the nervous system
What are some of the roles of the Neuroglia?
Providing structural support for neurons.
Creating a blood-brain barrier.
Restricting movement of substances between the blood & tissue fluids within the CNS.
There are neuroglia that take on the role of phagocyte, removing debris & damaged tissue.
What makes up the cranial Vault?
Brain - 80%,
Cerebral blood - 12%,
Cerebral spinal fluid - 8%
What are the 4 major sections of the brain?
Brain stem,
Cerebellum,
Diencephalon, and
Cerebrum