MBB1 Flashcards
lecture 1
history of the brain
. adult weight is around 1400 grams
. 3% of our body weight and 20% of our energy resources are found in our brain
. Hippocrates said it was the centre of control
. Galen discovered sensory and muscle nerves
. Vesalius discovered the cortex which is composed of our gyri and sulci and meninges
. Descartes discovered link between the physical brain and non physical mind
. Galvani noticed that there is electricity that occurs with neural communication
. Gall noticed that facial features can be matched to our personality
. Broca discovered that the LFC is the site of expressive language
. Moniz relieved anxiety with Prefrontal leucotomy which is now banned
lecture 2 - M.S and neuron function
- what are symptoms of MS
paraplegia, weakness, numbness, visual problems and slurred speech
- this is because their immune system attacks the myelin sheath that surrounds our axons of neuron disturbing the transmission of action potential/stops communication
lecture 2 - MS and neuron function
- what is the role of myelin sheath?
allows electrical impulses to transmit quickly and efficiently along the nerve cells
lecture 2 - MS and neuron function
-functioning of a cell
. Dendrites allow neurons to communicate
. Axon is a passage that carries signals from the cell body
. Action potential is the signal that gets carried
. Terminal buttons secreted neurotransmitters to either excite or inhibit
. Cytoplasm has mitochondria which uses glucose to produce energy
lecture 2 - MS and neuron function
what does a change in membrane permeability cause?
action potential
lecture 2 - MS and neuron function
4 types of glial cells
- astrocytes which provide physical support and clean up waste to keep the extracellular fluids around cells in good condition
- oligodendrocytes which TOO give physical support but also insulation to axons alongside myelin
- microglia which act as phagocytes
- schwann cells which are like oligodendrocytes but for the PNS
lecture 2 - MS and neuron function
depolarisation
…occurs when a positive electrical current passes through making the sodium channels open
…membrane potential goes from a negative charge to a positive
…the current must be between -70mvs to 40mvs
lecture 2 - MS and neuron function
repolarisation
…occurs after depolarisation and potassium channels now open to bring back a balance as there is too much positive potassium now in the axon
lecture 2 - MS and neuron function
refractory period
…occurs when sodium channels close and cannot re open until the membrane reaches its resting potential again which is -70mvs
lecture 2 - MS and neuron function
role of the sodium potassium pump
…allows a cell to have both sodium and potassium inside during the change in membrane potential which is crucial for normal functioning
lecture 2 - MS and neuron function
hyperpolorisation
…potassium ions start to move out and the process of action potential can start again
lecture 2 - MS and neuron function
what medicine can be administered to allivieate MS
interferon b - aids the Nodes of Ranvier which have been disrupted
lecture 2 - MS and neuron function
what are the advantages of the action potential jumping along myelinated axons
1 it saves energy
2 it increases the speed therefore our reaction time is faster
lecture 2 - MS and neuron function
where are sodium ions most concentrated?
…outside of the neuron making the membrane potential more positive
…efflux of potassium however makes the membrane potential more negative
lecture 3
what is myasthenia gravis?
…a disorder of synaptic transmission
lecture 3
steps of neurotransmitter release
- enzymes
- NT release from the top
- NT binds to vesicles
- some enzymes degrade
- those that haven’t leave the pre synapse and attach to the post synaptic receptor
lecture 3
EPSP vs IPSP
EPSP - depolorises the postsynaptic cell and increases the chance of an action potential
IPSP - hyperpolorises the postsynaptic cell and decreases the chances of an action potential
lecture 3
what is reuptake?
occurs in the synaptic cleft and ensure there are no lingering NTs that did not make it into the postsynapse
lecture 3
what is enzymatic deactivation?
…deactivates enzymes after termination of postsynaptic potentials
lecture 3
types of amino acids and what they do
firstly, amino acids give our cells structure - building blocks
… one type is GABA which are inhibitory
… second is glutamate which are excitatory
…monomines which include seretonin and dopamine
… and then there are acetlycholine
lecture 3
agonist drugs vs antagonist
agonist - increase flow in synapse
antagonist - decrease ion flow at synapse
lecture 4 - structure and function of nervous system
- positions of our brain
- rostral (anterior)
- caudal (posterior)
- dorsal (fin/up)
- ventral (heart/below us)
lecture 4 - structure and function of nervous system
the meninges and what is involved in the meninges structure
the main role of the meninges is to protect our CNS and is made up of:
- the dura mater - protects skull
- arachnoid mater - allows CSF to flow through
- pia mater - only the PNS has pia mater and dura mater
lecture 4 - structure and function of nervous system
CSF
…is created by chorois plexus and re-absorbed into bloodstream. The lateral ventricle lets it flow out
…those with a blockage of CSF get a condition called obstructive hydrocephalus
lecture 5 - structure and function of nervous system
what do darker ares of the brain show?
…more neuron cell bodies
lecture 5 - structure and function of nervous system
hypothalamus vs thalamus
H –> controls our autonomic nervous system and endocrine system which regulates our survival behaviours
T –> the relay station for sensory inputs to the cerebral cortex
lecture 5 structure and function of nervous system
the spine
…we have 24 vertebrae in the spine
…spinal foramen is where the spinal cord passes through
…31 pairs of spinal nerves that receive and convey information
…12 cranial nerves associated with the sending and receiving of signals
lecture 6 - methods of testing peoples biological systems
…clinical neuropsychology attempts to explain brain behaviour relationships by looking at functioning patterns after damage. To be able to do this researchers look at patterns of association and dissociation
…limitations of clinical neuropsychology is that it cannot test in depth, hard to replicate and assumptions can be made that are incorrect
lecture 6 - methods of testing people
overcoming limitations of clinical neuropsychology with ablation studies
…ablation studies are means of testing animals
lecture 6
broca aphasic vs wernickes aphasia
B.A –> loss of speech
W.A–> cannot comprehend language
lecture 6
other methods of testing (other than clinical neuropsychology and ablation)
- structural brain imaging - ct scans and MRI
2. functional brain imaging - EEG, ERP AND fMRI
lecture 6 - methods of testing
fMRI
fMRI looks at oxyhaemoglobin which is diamagnetic and deoxyhaemoglobin levels which is paramagnetic
lecture 7 - visual system
cells of our retina
…1. ganglion cells
…2. bipolar cells
…3. photoreceptor layer
signals from cones and rods go from the bipolar cels to the ganglion cells
photoreceptor and bipolar cells do not produce action potentials instead they release neurotransmitters that either increase of decrease the firing rate of action potentials that are generated by ganglion cells
the retina has around 120million rods and 6 million cones
lecture 7 - visual system
wavelengths of cones
shortwavelength - blue light and most sensitive to 440nm
midwavelength - green light and most sensitive to 500nm
long wavelength - red light and most sensitive to 560nm
lecture 7 - visual system
rods vs cones
cones - active when there is more light and colour
rods - active when it is dark/monochromatic light
lecture 7 - visual system
ON and OFF cells
within the ganglion and bipolar cells; ON cells are excited by light in their centre and inhibited by light in their surrounding field
OFF cells are inhibited by light in their centre and excited by light in their surrounding areas
…a bar of light that passes over the oN region will increase firing rate of neuron and a bar of light that passes over the OFF region will decrease firing rate
lecture 7 - visual system
areas of vision in the brain
Primary visual cortex - V1/ injuries to this causes interruption of flow of visual info to the brain
V4 - neurons sensitive to colour
MT - neurons sensitive to movement
Inferior temporal cortex - aids recognition of complex objects and faces
damage to v4 - see things in black and white
damage to MT - akinestopsia/ unable to judge speed
propsopagnosia - cannot recognise famous faces
lecture 8 - auditory system
- basic knowledge; key words
as humans we can hear from 30-20,000 Hz
loudness = amplitude
pitch = frequency
timbre = complexity
- inner ear contains the cochlea which is the most important system for our hearing as sound waves cause the stapes to move in and out making fluid movement to the baslir membrane
lecture 8 - auditory system
how we hear
bending of hair cels is what produces receptor potentials converting sound waves in neural signals
lecture 8 - auditory system
cochlea implantation
- creates more excitation of inner hair cells while decoding complex sounds into individual frequencies
lecture 8 - auditory system
what is the somatosensory system?
- is the part of the sensory system concerned with the conscious perception of touch, pressure, pain, temperature, position, movement, and vibration, which arise from the muscles, joints, skin, and fascia
- within this is cutaneous sense which is incharge of touch e.g. pain
lecture 8 - auditory system
skin properties
hairy skin has rapid vibrations and free nerve endings that detect a change in temperature
glabrous skin = a more complex array of receptors found in areas that need is such as our fingers, mouth and palms
meissners corpuscles = are nerve endings that respond to taps, light touches and frequent vibrations (10-50Hz)
morkels disks = respond to indenting of skin
nocirecptor = respond to pain
ATP receptors = respond to muscle damage
Capsaicin receptors = respond to extreme heat
mechanoreceptors = respond to hitting, stretching or pinching
Phantom limbs = sensations from a limb that are no longer there
lecture 9 - sensorimotor system
how are our muscles fibres stimulated?
…neural signals from motor neurons in our spine exit via the ventral root to create an action potential which releases acetylcholine that stimulates the muscle fibres to change their length accordingly to perform the movement
lecture 9 - sensorimotor system
flexors, extensors, muscle spindles, reflex arc
flexors = flex a joint
extensors = straighten a joint
muscle spindles = provide information to the CNS regarding muscle lenght
reflex arc = helps maintain position of body such that when someone bumps you when you have hot tea for example your stretch reflex compensates to prevent you from falling over and spilling this hot tea over you that would hurt
you can test your relex arc with a patellar tendon test
lecture 9 - sensorimotor system
hierarchical organisation in sensorimotor system in the brain
- highest level of control patterns = association cortex e.g. prefrontal cortex and parietal
- motor cortex
- primary motor cortex
- brainstem motor nuclei
- spinal motor circuits
lecture 9 - sensorimotor system
senses controlled in the brain
…basil ganglia - controls motor behaviour such as sequencing of movement and voluntary movement
…huntingdons disease and parkinsons are due to damage to the basil ganglia
…lesions to cerebellum disrupts a persons ability to control direction, force etc. of voluntary movements and cannot adjust to walking on different surfaces such as a bumpy road
