Biological Basis Flashcards
What is the mind versus body debate?
A debate over whether the the mind and the brain are seperate and distinct entities or the same thing.
What did most Greek philosophers believe in the mind vs body debate?
That the mind and body (brain) were seperate entities and that the mind controls the body but the body cannot control the mind.
How long was the Greek philosophers view popular?
It was popular for about 2000 years until French philosopher Rene Descartes in the 17th century
What did Rene Descartes believe?
That the mind is a non-physical entity (soul) that is seperate form the physical fleshy structure of the brain (matter). He agreed that the mind and body were different things
What was Descartes belief called?
Dualism
How did the mind and body come into contact?
Through the pineal gland which allows the mind and the brain to interact to produce thoughts, feelings, sensations and conscious experiences. He thought that the mind could affect the brain and visa versa.
How has Descartes been proven wrong?
The pineal gland is a small structure in the centre of the brain that is part of the endocrine system not the nervous system.
What is the endocrine system?
A system of glands that secrete hormones into the bloodstream.
Who did the split brain experiments?
Sperry
What happened in the surgery of the split brain experiment?
The corpus callosum was cut (the bridge of nerve fibres connecting the two hemispheres)
What happened in terms of impairment to the patients in Sperry’s experiment?
Generally the suffered little to no impairment but there were some irregularities.
Where is information the left visual field processed?
The right hemisphere
Where is information in the right visual field processed?
In the left hemisphere
What was the method of the sperry experiment?
A patient looked at a black dot in the middle of a screen. A picture of a spoon was flashed to the right or left of the dot.
The patient was unable to say what the object was when it was seen in the left visual field but they could feel for it with their left hand and locate the correct object.
What are the results of the Sperry experiment?
When a patient sees something in the left visual field (processed by the right hemisphere) the patient was unable to say the name of the object. This was because information was unable to travel from the right hemisphere to the left hemisphere (where speech processing is located) without the corpus callosum.
What is the conclusion of the Sperry experiment?
The corpus callosum has a vital role in language and speech. It shows support for specialised functions in different hemispheres: left hemisphere specialises in language and right is involved in non-verbal visual tasks.
What are some brain recording and imaging techniques?
CT Scan, PET and MRI
What does CT stand for? When is it used?
Computerised tomography. When you can’t use an MRI
Who preforms a CT scan?
A radiologist
What is a patient injected with for a CT scan and why?
A substance called contrast (iodine based) which is absorbed by blood vessels and makes it easier to identify brain structures.
How does a CT scan work?
At each position it sends a small amount of radiation (X-rays) through the skull and brain creating a cross sectional image. Adjacent slides can be combined to create a 3D image
What are the benefits of a CT scan?
It is extremely useful at showing damage or abnormalities in brain structures. Shows soft tissues eg. Tumors better than an X-ray. It is more clear that an X-ray.
What are limitations of a CT scan?
It does not provide information about brain function, it involves using powerful X-rays and can not be repeated for several months. It is not as clear as a MRI and is slightly invasive because of the injection of contrast.
What is the output of a CT?
Structure
What does PET scan stand for? What is its output?
PET means Positron Emission Tomography. It’s output is function. It’s provides information about the levels of activity in different areas of the brain surfing certain tasks.
What substance is injected into a patient of taken orally? Why?
A radioactive substance that is glucose. It emits signals that that are detected by a sensitive device and recorded in the PET computer.
How does the radioactive substance for PET work?
More active brain areas require increased blood flow as there is more neuronal activity. The increased blood flow means that more radioactive substance is sent to that brain area, emitting stronger signals that less active brain areas.
What are PET scans and what do they look like?
The images are compiled to make a coloured map of brain activity.
What are the benefits of PET scans?
They provide detailed information about brain function. Researchers can understand which areas are active during certain tasks, it can be used on healthy participants.
What are limitations of PET scans?
It is mildly invasive (injected substance), it can only be done of a person a number of times because of the radioactive agent, images are not clear about structure, radioactivity decays quickly so investigation must be short, pictures are taken every 40 seconds so it doesn’t pick up rapid progression of the brains activity.
When are PET scans used?
When you want to see the functioning of the brain for short tasks.
What does MRI stand for? What is the output?
Magnetic Resonance Imaging. It is structure.
How does an MRI work?
A patient enters a large chamber and lies very still. Large magnets create a magnetic field which vibrates atoms in the brains Neurons. A computer processes the vibrations. Different types of tissue respond differently to the magnetic field. The computer senses these differences.
What are benefits of an MRI?
It allows for precise location of structural damage in the brain. It is non invasive (no X-rays, injections or radioactivity), provides a high quality photo that can be seen horizontally, vertically and sideways. It is clearer than a CT scan.
What are limitations of MRI scans?
Cannot be used on people with metallic devices (pacemakers), requires a patient to lie very still (small movements may cause ghosting in the scan), cannot be used on uncooperative or claustrophobic patients.
When is an MRI used?
When you want to see a highly detailed image of the brain.
What part of the body is the master of information?
The brain, it is the processing and decision making organ.
What does the brain do with neural messages?
It receives and interprets information from the sensory systems and sends motor messaged out to all parts of the body so that a co-ordinated and appropriate response can be made.
What is the spinal cord and where is it?
It is a complex cable or tract of nerve fibres stretching form the base of the brain to the lower back.
How does the spinal cord act like a connection?
It connects the brain to other parts of the body via its connection to the peripheral nervous system. It is like an information super highway.
The spinal cord receives…
Sensory information from the peripheral nervous system and transmits it to the brain.
The spinal cord transmits….
Motor messages from the brain to the PNS
What happens if there is damage to the spinal cord?
It may mean that the motor messages can no longer reach the muscles in the body and that sensations in these muscles will not be registered.
What are the specifics of when the spinal cord is damaged?
The brain loses the ability to send motor information to the muscles, organs and glands AND receive sensory information from sensory receptors.
How does the severity of paralysis to the body because of spinal cord damage change?
It depends where the spinal cord is damaged and how badly it is damaged.
What are sensory Neurons?
They are specialised cells that receive information from outside and inside the body.
How do sensory neurons react to a stimulus?
They detect and respond to specific information. They transmit information to the central nervous system. Information is received from the external environment via the sense organs and from internally within the body from muscles, organs and glands.
How is the structure of a sensory neuron different?
It contains a sensory receptor to receive incoming sensory information.
What are sensory Neurons also called?
Afferent neurons
What do motor neurons do?
The transmit messages from the CNS to the muscles, glands and organs. Motor neurons enable muscles to move, cause glands to secrete chemicals and activate organs.
How are motor neurons different to other neurons?
Their axon is covered in myelin sheath. This allows motor neural impulses to travel faster.
What are motor neurons also called?
Efferent neurons.
Where are interneurons located?
Only within the CNS
What do interneurons do?
They carry and integrate messages between sensory and motor neurons as motor and sensory neurons don’t send messages to each other.
What is a soma?
Also called the cell body and it is the structure that determines whether the neuron will be activated and thus transmit messages to other neurons.
What is a dendrite?
From the Greek work meaning tree. It is a short, thin, widely branching nerve fibre that detects the receives neural information.
What is an axon?
A single tube like, fluid filled detention that transmits messages from the soma to other cells in the body including other neurons, muscles, organs and glands. It is encased in myelin sheath.
What is myelin sheath?
A white fatty substance that helps speed up transmission of neural impulses. It insulates the axon.
What are axon terminals?
At the end of each axon there are branches called axon terminals.
What are synaptic knobs or terminal buttons?
They are small knob-like swelling structures at the tip of axon terminals. It stores chemicals neurotransmitters.
What are neurotransmitters?
They are chemicals that assist with the transmission of neural information from one neuron to another across synapses.