Medical Imaging Techniques Quiz

Neural Structure and Function

• A sensory neurone transmits impulses from receptors to relay neurones in the CNS.
• A relay neurone exists in the CNS and connects sensory neurones with motor neurones.
• A motor neurone transmits impulses from the CNS to effectors.
• Dendrons are extensions from a nerve cell that carry impulses towards the cell body.
• Axons are extensions from a nerve cell that carry impulses away from the cell body.
• Schwann cells form the myelin sheath around nerve cells in the peripheral nervous system.
• Myelination is the formation of a myelin sheath around nerve cells by Schwann cells.

Neural Signaling

• A stimulus is a change in internal or external conditions which brings about a response.
• A receptor is a structure that acts as a transducer by detecting changes in the environment and converting them into electrochemical impulses.
• An effector is a muscle or gland that produces a response to a stimulus.
• Saltatory conduction is the setting up of localised circuits between nodes of Ranvier which allows for the rapid propagation of an action potential.
• Nodes of Ranvier are unmyelinated sections of nerve cells which allow for the propagation of an action potential due to their many ion channels.

Synaptic Transmission

• A synapse is the junction between two nerve cells or a nerve cell and an effector.
• A neurotransmitter is a chemical that diffuses across the synaptic gap to stimulate other neurones or effector cells.
• Acetylcholine is a neurotransmitter used in the parasympathetic nervous system.
• Depolarisation is the rapid influx of sodium ions into the cell which causes it to lose its negative charge and the membrane potential to increase.
• Hyperpolarization is the drop in membrane potential below the resting potential after repolarization due to open potassium ion channels.

Vision

• The pupil is the hole in the centre of the iris which can contract and dilate using the iris to alter the amount of light which contacts the retina.
• The iris is the pigmented muscular ring that surrounds the pupil and controls its diameter.
• The retina is the structure at the back of the eye which is composed of photoreceptors and is specialised to detect light.
• Rhodopsin is a protein found in rod cells that converts dim light into an electrochemical impulse.
• Rods are a type of photoreceptor found in the retina which is specialised to work in dim light.

Brain Imaging and Function

• Functional magnetic resonance imaging (fMRI) is a medical imaging technique that uses radio waves and a magnetic field to assess brain function through the visualisation of blood flow in brain capillaries.
• Positron emission tomography (PET) is a medical imaging technique used to assess organ and tissue metabolic function through the use of radioactive molecules and computer analysis.
• Computed tomography (CT) scan is a type of medical imaging technique that uses several x-rays and computer software to create detailed images of structures and organs inside the body.

Neurological Disorders

• Parkinson’s disease is a neurodegenerative disease which affects the dopamine secreting neurones and leads to a decrease in motor functions and tremors in resting muscles.
• Dopamine is a neurotransmitter involved in signalling pathways associated with the brain’s reward system.
• Serotonin is a neurotransmitter involved in signalling pathways associated with happiness and mood regulation.