The Brain and Nervous System Flashcards
What is the human nervous system and what are its two functions?
It is the network of nerve cells and fibers which transmits nerve impulses (messages) between parts of the body. It receives and processes sensory info from the environment and it transmits motor info around the body.
Describe motor and sensory info
sensory; information about the external environment carried from sensory organs
motor; information about how to respond to external environment carried from brain to internal organs (e.g muscles)
What are the two major divisions of the Nervous system and what do they consist of?
Central Nervous System (Brain & Spinal Cord)
Peripheral Nervous System (all other nerves)
Draw the human nervous system
Nervous system > central and peripheral nervous system > brain/spinal cord and automatic/somatic nervous system > sympathetic/parasympathetic and sensory info/voluntary skeletal muscles
What does the spinal cord do and what are its functions?
It connects the brain to the rest of the body. Functions = 1) Send info from sensory neurons in various parts of the body to the brain & 2) Relay motor commands back to muscles and organs via motor neurons
What is the function of the Brain?
The Brain receives and processes information and coordinates a response.
What is the Peripheral nervous system and what does it do?
The Peripheral nervous system is connected to the spinal cord and consists of all nerves outside the CNS. It carries sensory info from body to CNS and motor info from CNS to body. It consists of the Somatic (voluntary) and Autonomic (involuntary) NS.
Compare the roles of the CNS and the PNS?
CNS; receive and process info and coordinate response
PNS; take sensory info to CNS and motor info from CNS to body.
Explain the role of the somatic nervous system?
Somatic nervous system transmits sensory info to CNS and carries out its motor commands. It is involves in voluntary skeletal movements.
Explain the role of the autonomic nervous system?
Autonomic nervous system is responsible for autonomic responses. It carries info between CNS and internal bodily structures (e.g heart) It is divided into two main systems; Sympathetic and Parasympathetic.
Describe the sympathetic nervous system and examples
Sympathetic nervous system = readies the body for fight or flight response when its exposed to threats (stressors)
Examples = dilates pupils, increases heart rate, slows down digestion
Describe the parasympathetic nervous system and examples
Parasympathetic nervous system = slows things down and calms body down after a stress response and maintains homeostasis.
Examples = pupils constrict, heart rate lowers, digestion increases
What are the types of neurons, where are they located and what are their roles?
Sensory (PNS)(Afferent) = transmit info from sensory organs to brain
Motor (PNS)(Efferent) = transmit commands from interneurons to the glands, organs and muscles of the body
Interneurons (CNS) = organize and integrate sensory info in the brain and initiate and coordinate motor responses.
Function of dendrites?
Receives input from other neurons
Function of cell body/soma?
Contains the nucleus which controls the neuron
Function of axon?
Transmits information to other neurons
Function of myelin sheath?
Protects and insulates axon and speeds up speed of neural transmission
Function of axon terminal?
Allows for the branching out of the axon contains synaptic knob at end of terminal
Function of synaptic knob?
Contains vesicles which release neurotransmitters when moving signals to adjacent cells
Function of synapse?
The space between neurons where transmission occurs
How do neurons communicate?
Electrochemical energy
Explain the two types of communication for neurons
Electrical - within the neuron > electrical impulse is transmitted along the axon
Chemical - between neurons > takes place in synapse when neurotransmitters are send from axon terminals of the pre-synaptic neuron to the dendrites of the post-synaptic neuron
What do Glial cells do and what are some of their functions?
Glial cells provide the structural framework that enable a network of neurons to remain connected. Functions = supply oxygen and nutrients to neurons so they can function, destroy and remove dead neurons, soak up excess neurotransmitters at the synapse that can clog communication between neurons
What is the synapse?
The area where neurons meet (but can never physically touch)
Describe the process of chemical communication
- Vesicles store neurotransmitters within the nerve cell
- When an action potential reaches the axon terminals, the synaptic vesicles release neurotransmitters into the synapse
- These neurotransmitters attach to the receptor sites of the post synaptic neuron and alter its action.
Describe the lock and key process
Lock = receptor site
Key = neurotransmitter
The neurotransmitter will bind with the receptor site if there is a complementary molecular structure.
Describe what happens after the neurotransmitter binds to the receptor site
-Inhibitory response; they inhibit the post synaptic neuron and make it less likely to fire an action potential
-Excitatory response; the excite the post synaptic neuron and make it more likely to fire an action potential.
Provide an example of an excitatory neurotransmitter (and what happens with too much of it)
Glutamate = more likely to fire an action potential when binded with a receptor site. Associated with cognition, memory, learning, behaviour etc
Too much glutamate > abnormal neural development, neurodegenerative diseases
Provide an example of an inhibitory neurotransmitter (and what happens with low levels)
GABA = less likely to fire action potential, slows down neural transmission and reverses effect of excitatory neurotransmitters.
Low levels = high levels of anxiety
What is the cerebral cortex?
It is the outer layer of the cerebrum, divided into two halves called hemispheres and plays a key role in memory, cognition, thought etc
Function and structure of cerebral cortex
Function; Receive and process sensory info & initiate motor response
Structure; Two hemispheres (left and right) and four lobes in each hemisphere
What does contralateral organization mean?
It means opposite sides. The right hemisphere receives sensory info from the LHS of the body and controls movements on the LHS of body. The opposite is true of the left hemisphere.
What does hemispheric specialisation mean?
The brain functions as a whole but the right and left hemispheres do seem to have specialized roles.
Functions of left hemisphere?
Speaking, logical reasoning, writing, sensory and motor functions from the RHS of the body
Functions of right hemisphere?
Sensory and motor function of LHS of body, art and music, spatial and visual thinking
What is the corpus collosum and what is its function?
Corpus collosum = bridge of nerve tissues that connects the two cerebral hemispheres. It allows for communication between the two hemispheres. (doesn’t send messages, but allows for messages to be sent)
What are the ten things needed to be labelled on a brain?
Frontal, Parietal, Occipital, Temporal Lobe, Primary motor cortex, Primary Somato-sensory cortex, Primary visual cortex, Wernicke’s area, Primary auditory cortex, Broca’s area
Explain the primary motor cortex
It is located in the frontal lobe. It controls voluntary bodily movements of skeletal muscles and is organized contralaterally.
Special things =
- parts higher on body are controlled by lower parts of primary motor cortex
-areas of body requiring greater dexterity and complexity of movement have greater area of cerebral cortex for them
Functions of frontal lobe
planning, personality, thinking, decision making
What is Broca’s area and where is it located?
It is located in the left frontal lobe and it ensures speech production and articulation of speech
Explain the primary auditory cortex
It is located in the temporal lobe. Plays a role in being able to perceive sound. (Verbal sounds generally in LH and non-veral e.g music in RH)
Functions of temporal lobe
Memory, hearing, face and object recognition
Compare Broca’s area and Wernicke’s area
Broca’s area = speech production and articulation centre of brain
Wernicke’s area = understanding and processing (comprehension) of language
Explain the Primary Somato-sensory cortex
Receives and processes sensory info from skin and body
What does spatial neglect mean?
Defined by the inability of a person to process and perceive stimuli on one side of the body or environment.
Explain the Primary visual cortex
processes info from eyes
Other functions of occipital lobe
vision, shape, colour, perspective
Brief explanation of neural pathways from the eyes
RVF going to left receptive field and then to left visual cortex and vice versa
Define the Limbic System
It combines higher order mental functions and primitive emotion into one system.
Name the primary structures in the Limbic System
Amygdala, Hippocampus, Thalamus, Hypothalamus, Basal Ganglia, Cingulate Gyrus
Explain the location of the amygdala, what it looks like and its function?
-Small, almond collection of neurons located deep inside temporal lobe (located at end of hippocampus)
-Responsible for emotional reactions especially processing fear. Other functions include learning new information and decision making.
What would happen if you had damage to your amygdala?
Loss of fear response, Impaired decision making, memory loss, hyper vigilance
Explain the location of the hippocampus what it looks like and its function?
It looks like a seahorse and is located deep in the temporal lobe. It’s function is to transfer short term memories into long term memories.
What happens if you have damage to your hippocampus?
Unable to create new, long term memories and is associated with Alzeimer’s and severe depression
Explain the location of the thalamus, what it looks like and its function?
It is located in the centre of the brain and acts as a sensory way station and filter for the brain.
What happens if you have damage to your thalamus?
Risk of coma, sensory changes, movement disorders or lack of movement
Explain the location of the hypothalamus, what it looks like and its function?
It is small part of the brain located just below the thalamus. It is responsible for the maintenance of the internal physiological state of the body and maintaining homeostasis. E.g regulating BP, temperature regulation
What could happen if you have damage to your hypothalamus?
Lose the capacity to feel full so constantly eating > obese
Explain the location of the cingulate gyrus, what it looks like and its function?
Long thing through centre of brain. Its function is coordinating smells and sights with pleasant memories as well as emotional responses to pain and decision making
What happens if you have damage to your cingulate gyrus?
Depression, anxiety disorders, ocd
Explain the location of the basal ganglia, what it looks like and its function?
It is a group of cells located deep in the frontal lobes. Its functions are organising motor behaviour and coordinating rule based, habit learning such as when to start or stop an action (walking) as well as procedual memories
What happens if you have damage to your basal ganglia?
Problems with speaking, moving, posture
Explain how a CT works
Computerised Tomography and is a neuroimaging technique that produces a computer enhanced image of a cross section from x-rays taken at different angles. Used to locate structural brain abnormalities, a contrast dye is used to help see certain structure
What are the advantages and limitations of a CT scan?
+ve = provides clear and accurate images, relatively non-invasive
-ve = only shows structure not function, pregnant women can’t have due to x-ray radiation
Explain a PET scan
Provides information regarding function and activity of brain during tasks by monitoring where the flurodeoxyglucose travels around the brain. Different colours indicate different levels of brain activity. Purple and blue = least activity and red = most
Explain the advantages and disadvantages of a PET (Positron Emission Tomography)
+ve = colour coded images of brain, colours make interpretation easier, can see functioning of brain during tasks
-ve = requires injection of radioactive material, 40 sec of rest needed between 30 second scan
Explain how a MRI works
Uses strong magnetic fields and radio signals to generate signal from the body and then pick them up to create pictures of soft tissue of body
What are the advantages and disadvanatges of a MRI
+ve = clearer and more detailed than CT, non invasive, no x-ray radiation
-ve = only shows structure-not function, cannot be used on people with internal metallic structures
Explain how a fMRI machine works
Use of blood and oxygen levels to show brain image and functioning of neurons.
Explain the advantages of disadvantages of a fMRI machine works
+ve = detailed images of brain functioning, combination of structure and function
-ve = expensive, limited acces
What does EEG stand for?
Electrocephalograph
Explain how an EEG works and what happens?
It detects, amplifies, records general patterns of electrical activity within the brain by placing electrodes on the scalp.
Explain the advantages of disadvantages of a EEG machine works
+ve = provides overall info about brain, used to study pattern of brain over long time (e.g sleeping)
-ve = no detailed info about structures of brain, can’t pin point specific areas of activity
What are drugs?
A drug is any substance (with the exception of food and water) which when taken into the body alters the body’s function either physically or psychologically .
Explain psychoactive drugs and the examples
= they affect the central nervous system and alter a person’s mood, thinking and behaviour
e.g = depressants, stimulants, hallucinogens
Explain what depressants do and the examples
They slow down the activity of the central nervous system. e.g alcohol, heroin
Explain what stimulants do and the examples
They increase the functioning of the cns. e.g cocaine and ice
Explain what hallucinogens do and the examples
They produce perpetual and temporal distortions and affect perception and thinking. e.g magic mushies
Explain cannabis
Doesn’t fit neatly into any category because has elements of a stimulant, depressant and a hallucinogen
Compare drug dependence and drug addiction
Dependence = physiological = body is reliant on the drug
Addiction = psychological = difficulty controlling amount or actually taking it
How are neurotransmitters and drugs linked?
Neurons communicate by releasing neurotransmitters. These chemicals can be mimmicked or mannipulated by psychoactive drugs. Most illegal drugs mannipulate release of dopamine and serotonin
Explain dopamine
It is a pleasure hormone and linked to learning through reward. Experiences that someone finds pleasurable will always involve release of small amount of dopamine release
What is the mesolimbic pathway?
Transports dopamine from the Ventral Tegmental Area to the rest of brain?
What is the VTA?
Ventral Tegmental Area and one of the prime places of dopamine production in the brain
What does serotonin do?
Linked to one’s mood, emotions and happiness
Explain what happens when someone takes ecstasy
It is a stimulant and causes the release of most of the neuron’s serotonin. Can lead to euphoric state of being and increased energy. Side effects = nausea, sweating, faint
What does withdrawal mean?
Taking a psychoactive drug indicates to body that it can receive neurotransmitters from external sources > body responds by reducing production of it
