Review. Flashcards
What is the nervous system?
The system the body uses so that different parts of the body can communicate with each other.
What is governed by the nervous system?
The body’s actions and reactions.
What are the 3 basic functions of the nervous system?
Detecting a stimulus.
Processing information from that stimulus.
Responding to that stimulus.
What part of the nervous system picks up a stimulus?
Afferent/sensory neurons.
What part of the nervous system is involved in processing a stimulus?
Interneurons.
What part of the nervous system will deliver the brains response to a stimulus?
Efferent/motor neurons.
Will external and internal stimuli be transmitted around the body in the same way?
Yes.
What are 7 steps of the journey that a stimulus takes from the moment it has been felt to the point where a response is delivered?
Stimulus picked up by an afferent neuron.
Afferent neuron transmits stimulus to the CNS.
CNS takes stimulus to brain.
Inter neurons in brain process stimulus.
Brain makes a response.
Efferent neuron deliver response to PNS via CNS.
Response arrives at effector cell and is acted upon.
What are neurons?
Nerve cells that are able to generate, conduct and respond to an action potential.
Where is the nucleus found in a neuron?
In the nerve cell body.
What are the 2 different projections that project off a nerve cell body?
Axons.
Dendrites.
Are there multiple dendrites and axons that project off a nerve cell body?
There are multiple dendrites that branch off a nerve cell body, but only a single axon.
What is the role of the dendrites?
To bring sensory information into the nerve cell body.
What happens once sensory information is bought into the nerve cell body via the axons?
It is transmitted to the CNS or to the dendrites of other neurons by the cells axon.
Will a nerve cell body have multiple axons?
Yes, often there are hundreds of different axons communicate with a single nerve cell body.
How does a stimulus move from 1 neuron to another neuron?
It jumps from 1 neuron to the next in a process is called a synapsis.
What is a synapse?
An incoming stimulus that generates a graded potential in the neuron that receives it.
When will a synapse be able to initiate synapsis?
If the stimulus is strong enough it triggers an action potential that can then be passed on to another neuron via synapsis.
What is always involved between communication between nerve cells?
Ionic flow or electrical currents.
What kind of ion channels are always open?
Leak channels.
What moves down leak channels?
Ions that are moving from an area of high concentration to low concentration.
What kind of channels only open following a stimulus?
Gated ion channels.
E.g. Voltage gated channels or ligand gated channels.
What is major extracellular ion?
Sodium.
What is major intracellular ion?
Potassium.
What maintains the intracellular concentrations of sodium and potassium?
The sodium potassium pump.
What are the 2 classes of neurotransmitter?
Excitatory.
Inhibitory.
What is the role of excitatory neurotransmitters?
They cause depolarisation in the cell membrane.
What is the role of inhibitory neurotransmitters?
They hyperpolarise the cell membrane.
What happens if excitatory potentials arrive at a neuron?
They reach the threshold and trigger an action potential.
This sends a stimulus along the axon and towards the CNS or to another axon.
At what point of the axon will the action potential overcome the threshold?
At the axon hillock/trigger zone.
What kind of animals will the forebrain be found in?
In more highly evolved species.
What is controlled by the hypothalamus?
The autonomic nervous system and the endocrine system.
Where do almost all of the cranial nerves enter or exit the brain?
All cranial nerves except for cranial nerves 1 and 2 enter and exit the brain at the brainstem.
How many cranial nerves are there?
12 pairs of cranial nerves.
12 on the left side and 12 on the right.
How many cranial nerves enter the brainstem?
10.
What is the function of cranial nerve 1?
Smell.
It is the olfactory nerve.
What is the function of cranial nerve 2?
Sight.
It is the optic nerve.
What cranial nerves bypass the brainstem
Cranial nerves 1 and 2.
What part of the brainstem do cranial nerves 3 and 4 originate from?
The mesencephalon.
What is cranial nerve 5?
The trigeminal nerve.
What part of the brainstem do cranial nerve 5 originate from?
The pons.
What part of the brainstem do cranial nerves 6 to 12 originate from?
The myelencephalon.
What are the 3 areas found in the reticular area of the brain?
The reticular activating area.
The thalamus.
The reticular formation.
Where are the thalamus, reticular formation and RAS located in the reticular area of the brain?
The thalamus is dorsal.
The reticular formation is ventral.
The reticular activating system is in between the 2.
What information passes through the RAS and thalamus?
All sensory information.
Is the thalamus always active?
Yes.
Where does the body filter all incoming sensory information?
In the thalamus.
What areas of the brain are said to be the seat of consciousness?
The reticular activating area.
The thalamus.
The reticular formation.
What is the role of the thalamus?
It determines what information enters the brain.
What happens to the reticular area of the brain when we are sleeping?
No information will enter the cortex.
What is the limbic system?
A belt of interconnected tissues within the forebrain.
What is the major area the brain that deals with behaviour, emotions and memory?
The limbic system.
What are of the brain is involved in olfaction (smell)?
The limbic system.
Why can emotions activate the autonomic nervous system?
As the limbic system is connected to the hypothalamus.
What is found within the grey matter of the spinal cord?
The nerve cell bodies/nuclei.
What is found within the white matter of the spinal cord?
The myelinated axons.
Sensory neurons will arrive at what part of the spinal cord?
At the dorsal horn.
Motor neurons are released from what part of the spinal cord?
The ventral horn.
What kind of information runs up the spinal cord to the brain?
Sensory information.
What kind of information runs down the spinal cord from the brain?
Motor information.
Can a spinal nerve carry both sensory and motor fibres?
Yes.
Where are the cell bodies for all motor neurons located?
In the ventral grey horn.
What is a spinal cord section?
A spinal cord section is defined by the spinal nerve that leaves that area.
E.g. Section 10 is the area where spinal nerve 10 leaves the spinal cord.
What is a spinal cord tract?
A bundle of axons that have the same function.
What are the 3 functional areas of the brain?
Forebrain.
Brainstem.
Cerebellum.
What is released by each functional area of the spinal cord?
A pair of spinal nerves.
How many cervical spinal nerves are released in all species?
8 .
What spinal nerves exit the spinal cord in the neck region?
Spinal nerves C1-C5.
What nerves form the brachial plexus?
Spinal nerves C6 and T1-T2.
What is innervated by the brachial plexus?
The forelimb.
What name is given to the nerves that exit a plexus?
Peripheral nerves.
What nerves will give information to a peripheral nerve?
Multiple spinal nerves.
Do spinal nerves T3-L3 form a plexus?
No, they will travel to their destination as spinal nerves.
What spinal nerves form the lumbosachral plexus?
Spinal nerves L4-S2.
What is innervated by the lumbosachral plexus?
The hindlimb.
What does a plexus allow nerves to do?
To exchange information between different nerves.
What is a plexus nerve?
A nerve that emerges from a plexus and travels to an effector cell or vice versa.
