Nervous System Flashcards
Learn the basics about the body's main communication and coordination network: The Nervous System.
What is the purpose of the Nervous System?
The main communications system for the body responsible for receiving and interpreting information between parts of the body and brain.
What are the parts of the Nervous System?
Two main parts:
- The Central Nervous System
- The Peripheral Nervous System, which includes the the Autonomic Nervous System part.
What is the Central Nervous System comprised of?
- The Brain (main communication part)
- The Spinal Cord (conveys sensory impulses and co-ordinates reflex actions)
- The Cerebro-spinal Fluid (fluid in the brain and spinal cord that delivers nutrients to the CNS, removes waste and acts as a shock absorber if the brain experiences trauma)
- Meninges (3 layer cover to protect the Spinal Cord)
What are the types of Neurons (aka Nerves) and where do they originate?
- Motor (efferent) nerves. Conveys impulses from the brains, through the spinal cord to the muscles, glands and smooth muscular tissues.
- Sensory (afferent) nerves. Conveys impulses from sensory nerve endings in the organs and skin etc. to the brain via the spinal cord.
- Mixed nerves. A combination of Motor and Sensory nerve endings.
What are the core components of a Neuron (aka Nerve)?
- Cell body incl. the nucleus.
- Dendrites. Several short projections that RECEIVE info into the Cell body.
- Axon. One long projection that conducts information AWAY from the Cell body. it can only send information in one direction.
What are the two types of neuron/ nerve?
- Sensory nerve (info for brain to act on)
- Motor nerve (info telling the muscle or gland what do do)
What is the process for information being moved to the cell and onwards to the brain?
A sensory receptor in the skin picks up a message e.g. cold or pain, and sends the message as an electrical impulse to the Dendrite. The message is then moved through the cell back out of the Axon on to another nerve and back to the brain to make a decision on what action to take.
When would information from a sensory receptor not be passed on to the brain?
When it is a spinal reflex and is dealt with by the spinal cord. This is an involuntary action when a fast response is required aka a reflex action via the motor point (where the nerve inserts to the muscle belly to produce a muscle contraction). A message will still be passed on to the brain to inform it of what has happened.
What makes up the Peripheral Nervous System?
- 31 pairs of spinal nerves
- 12 pairs of cranial nerves
- The Autonomic part of the Nervous System (the involuntary part)
What type of muscles are the Autonomic Nervous System made up of?
Smooth and cardiac muscle.
What are the component parts that make up the Autonomic Nervous System?
They perform opposing actions:
- Sympathetic system (active in times of stress to e.g. activate release of adrenalin to the blood)
- Parasympathetic system (active in times of peace and mainly the Vegas nerve e.g can send impulses to slow the heart down)
What nerve in the Cranium gives us our sense of smell?
Olfactory nerve.
What does the Limbic System do?
It sits at the top of the brain stem and receives messages from the olfactory, auditory, visual, balance and the equilibrium systems for onward movement to the cerebral cortex to allow for the integration of emotion and reasoning.
Why is there a relationship between our sense of smell and emotions?
The Limbic System is connected to the thalamus, hypothalamus and pituitary gland, which explains why the olfactory system can have an impact on the endocrine function. E.g. aromatherapy is used to promote a feeling of wellbeing, relaxation etc.
