NUR121 Flashcards
(128 cards)
1
Q
main parts of the central nervous system system
A
brain and spinal cord and PNS everything else including cranial nerves and spinal nerves that leave to the periphery
2
Q
what 2 pathways come from the peripheral nervous system
A
• From peripheral ns there is afferent (sensory) and efferent (motor) division
3
Q
nerous system pathway from the motor efferent division
A
Motor/ efferent pathway has the somatic nervous system and the autonomic nervous system
4
Q
nervous system pathway from the autonomic nervous system
A
• The autonomic nervous system can then be divided into the sympathetic and the parasympathetic pathway
5
Q
main parts of peripheral nervous syetm
A
• Peripheral nervous system consists mainly of fibres cns really contains most nerve cell bodies
6
Q
types of cells in the nervous system
A
- Glia CNS
- Glia PNS
- Neurons or nerve cells
7
Q
describe glia of CNS
A
Astrocytes – most abundant, support, assist with exchange between capillaries and neurons
Microglial cells – health monitors of neurons, can act as phagocytes (as immune cells cant really get into cns)
Ependymal cells – line the brain cavities, involved in fluid exchange and circulation of CSF
Oligodendrocytes – produce myelin sheath ( insulation around axon)
8
Q
describe glia of PNS
A
Satellite cells – similar to astrocytes, surround nerve cell bodies
Schwann cells – create myelin sheath, similar to oligodendrocytes
9
Q
describe neurons/ nerve cells
A
Cell body with nucleus and organelles (ER = called Nissl bodies in nerve cells due to granular appearance)
Dendrites – receive input
Axon – send output (AP and synapses), can be myelinated or not
10
Q
neuron structure
A
- Cell body called soma
- Info comes through dendrite or straight into cell body
- Can see nissal bodes
- Long extension Is axon/ nerve fiber that end up in axon terminals ( secretory region as they secrete neurotransmitters
- Myline sheath has gaps in between called mylien sheath gaps or nodes of ranvier
- Cell membrane of axon called axolemma
- A bundle of axon is called a tract in the cns and a nerve in the pns
11
Q
how long can neurons live up to
A
• Nerve cells can live up to 100 years and longer and usually don’t divide
12
Q
do neurons have a high metabolic rate
A
Have very high metabolic rate and need loots of o2, will die in a few minutes without o2
• Lots of mitochondria
13
Q
types of neurons (structural)
A
Multipolar – many dendrites, one axon; most common, especially in CNS
Bipolar – one dendrite, one axon; rare, in eye and nose
Unipolar (or pseudounipolar) – one distal peripheral branch, one proximal central branch; mainly sensory neurons in the PNS
14
Q
types of neurons (functional)
A
Sensory or afferent – information towards CNS
(somatic, visceral)
Motor or efferent – signals away from CNS
(skeletal muscle fibres and motor fibres of ANS to viceral smooth muscle fibres/ glands)
Interneurons – association between nerve cells, often in between sensory and motor neurons 99% of neurons in brain but also in spinal cord
15
Q
what is a collection of neuron cell bodies called in the CNS VS PNS
A
CNS- NUCLEUS
PNS- GANGLION
16
Q
what is a tract
A
a bundle of axons in the CNS
17
Q
what is a nerve
A
a bundle of axons in the PNS
18
Q
how does information transfer happen in the nervous system
A
• Between nerve cells
• Use electrical charges that travel within neurons
• Use chemicals that bridge the gap between neurons (and effector cells, such as muscle fibres or glands)- usually neurotransmitters
• Use insulation (myelinated axons)
• Like a computer:
Many signals both with regards to time (temporal) and location (spatial)
Signals can either excite or inhibit the next area or neuron
Large network
19
Q
what is depolarisation
A
change of the original potential of -70mV towards 0 or even into positive
20
Q
Repolarisation?
A
return to the original negative potential
21
Q
Hyperpolarisation?
A
“overshooting” of the repolarisation into more negative
22
Q
Threshold ?
A
the depolarisation that is required to lead to a proper AP; it depends on the strength of the stimulus- positive feedback mechanism
23
Q
what are the different electric potentials in neurons
A
- Resting membrane potential
- Graded potential
- Action potential
- EPSP
- IPSP
24
Q
Resting membrane potential?
A
– established by K+ leaking out of the cell and the Na+/K+ pump
25
Graded potential ?
localised depolaristion or hyperpolarisation of the cell membrane; can only travel a short way; short-lived- usually happen at dendrites or the body of the nerve cells
26
Action potential ?
depolarisation triggered by Na+ influx into the cell; all or nothing rule
27
EPSP, excitatory post synaptic potential?
graded potential (depolarisation) at the postsynaptic membrane that leads to AP
28
IPSP,inhibitory post synaptic potential ?
graded potential (hyperpolarisation) at the postsynaptic membrane that decreases likelihood of an AP
29
Leakage channel ?
non gated channel; always open and allow Na+ to move into the cell and K+ to move out
30
Voltage-gated channel ?
opens or closes due to changes in membrane potential
31
Chemically gated channel
opens in response to the binding of a chemical, e.g. neurotransmitter, to a specific receptor
32
why more potassium out of cell then sodium
• Reason we have more k inside than outside is due to na k pump that pumps na out and k inside
33
grey matter?
nerve cell bodies and short unmyelinated axons and dendrites; distribution changes in different areas of the CNS, e.g. spinal cord vs cerebral hemispheres
34
white matter?
myelinated axons, often arranged in tracts
35
what are gradient potentials
* Happen when triggered by stimulus to receptor or because neighboring nerve cell stimulates the dendrite or it could even be the same nerve cell- gradient p from dendrite or cell body travels to cell axon causing ap in axon
* Gp are short lived potentials that travel only a short distance and are not very high
* There are 2 types: can either depolarize or can be hyperpolarisatiosn
* When they travel along the dendrite/ nerve cell they become weaker. Only if high enough will cause an ap. With hyperpolarization not a lot f chance so sort of inhibits passing on of a stimulus
36
how to normal action potentials in cells work
* Starts with rmp -70. Gradient potential cmes along for example and that changes the voltage Gatd channels causing sodium to enter the cell 9 depolarisation occurs)
* If reachines -55 millivolt threshold is reached then even more sodium enters and a proper action potential happens
* eventually sodium voltage gated channels close and voltage gated potassium gates open
* depolarization stops and repolarization occur movkng to resting membrane potential
* hyperpolarization- charges goes below initial negative charge as k leaves the cell and eventually returns back to resting membrane potential
* whilst those sodium channels are open, and depolarization happens if another stimulus arrives that cant trigger another action potential- called an absolute refractory period
* During repolarization, if a new stimulus arrives that could trigger another depolarization straight away but that can only happen if it’s a very strong stimulus.- relative refractory period
37
how can nerve cells tell if a stimulus is strong enough
he way the nerve cell knows if it’s a strong stimulus is that we have many action potentials , so we increase the frequency. The stronger the stimulus the faster we have action potential following. Frequency relates to intencity
38
t or f
Action potential is always the same around +30
t
39
how many gates on sodium channels vs potassium channels
* Sodium channels have 2 gates, start with activation gate so sodium can flow into the cell and once proper depolarization has been reached inactivation gate shuts and blocks more sodium from coming in
* Whereas potassium channel only has one gates
40
synapse?
area we connect from one nerve cell to another or one nerve cell to a muscle
41
how is an impulse transmitted accross a synapse
• When ap arrives it triggers calcium voltage gated channels to open and calcium eneters the channels and that gets vesicles to travel to the presynaptic membrane and to fuse with it and release their neurotransmitters stored in the vescicles
Nt travel across the synaptic cleft and bind to chemically gated channels on the post synaptic membrane and these chemically gated channels have receptors where the nt can bind
• That causes then movement of sodium potassium ions and lead to a graded potential which can the either cause an ap or not
• Get rid of neurotransmitters by either diffusing away and getting taken up by the blood or they can get taken back up into presynaptic area/ terminals or enzymes can split them up making them inactive
42
what is the refractory period
• Refractory period = while Na+ channels are open there can be no further AP, even if another stimulus occurs (absolute refractory period); during repolarisation, a strong stimulus can trigger another AP (relative refractory period)
43
what is a neurotransmitter
chemicals that get released into the synaptic cleft due to an AP; they bind to receptors on the postsynaptic membrane and trigger a graded potential
44
ways impulse can travel along an impulse
* Continuous conduction = APs passing along the axolemma, i.e. cause depolarisation of a neighbouring area, etc.
* Saltatory conduction = APs can travel along a myelinated axon (insulation) and only trigger the next AP at the gaps (nodes of Ranvier)
45
types of neurotransmitters
Acetylcholine (Ach) – can be both, very common in CNS and PNS
Noradrenaline – can be both, also in CNS and PNS
Dopamine – both, substantia nigra and other areas of CNS (“feel good” neurotransmitter
Serotonin – inhibitory, CNS (plays a role in mood, appetite, sleep)
GABA – main inhibitory, in CNS
Glutamate – main excitatory, in CNS
46
does continuous or saltatory conduction take longer
continuous
47
t or f
graded potential gets stronger further away from the stimulus
false]it gets weaker
48
look at brain diagram
diagram
49
what are the major brain structures
```
• Cerebrum (cerebral hemispheres)
• Diencephalon
• Cerebellum
• Brain stem
Midbrain
Pons
Medulla oblongata
```
50
gyrus?
Ridges of tissue, mainly nerve cell bodies
51
Sulcus?
grooves in between the gyri
52
Lobe
areas separated by major sulci, often coincides with specific functions
53
looking at the brain laterally what can be seen
frontal lobe, parietal lobe, occipital lobe, temporal lobe, transverse cerebral fissure, cerebellum, brain stem
54
what is a longtudinal fissure
split between 2 hemispheres
55
what are the different suculus and gyruses
look at diagram
precentral gyrus
central suculus
postcentral gyrus
lateral suculus
56
What is the reason for having a very convoluted brain, i.e. many sulci and gyri?
Larger surface area means a greater volume of grey matter, which in the cerebrum consists of
billions of interneurons.
57
Describe the distribution of white and grey matter in the different brain areas, including the
spinal cord. What do they represent?
Cerebrum: grey matter on the outside (cortex), white matter more internal (tracts connecting
different brain areas)
Midbrain, pons and medulla: Mostly white matter (various tracts, e.g. pyramidal tracts) with some
nuclei (grey matter)
Spinal cord: “Butterfly” structure of grey matter in the centre with anterior (motor neuron cell
bodies) and posterior horns (sensory neuron cell bodies) and interneurons; white matter around
(motor and sensory tracts)
58
. What are the layers of the meninges?
Dura mater = periosteal and meningeal layer, contains venous sinuses
(Underneath dura is subdural space)
Arachnoid = very fine connective tissue with fibres anchoring to pia mater
(Space between is called subarachnoid space- lost of large blood vessels in that area particularly arteries)
Pia mater = follows all the gyri into sulci
* Csf floats below arachnoid and surrounds the whole brain
* Csf can actually be extracted from spinal canal for testing
59
What are the subdural and subarachnoid spaces?
Subdural space = between dura and arachnoid, filled with fluid
Subarachnoid space = between arachnoid and pia, contains larger arteries and veins
60
important areas of cerebral hemisphere
```
Primary motor cortex
(precentral gyrus)
Primary sensory cortex
(postcentral gyrus)
Primary visual cortex
Broca’s area
Wernicke’s area
Prefrontal cortex
Basal nuclei
Corpus callosum
```
61
function of primary motor cortex/ precentral gyrus
precentral gyrus; large motor neurons (pyramidal cells); voluntary muscle movement → motor homunculus
62
Primary sensory cortex
| (postcentral gyrus) function
postcentral gyrus; receive information from somatic receptors in the skin and proprioceptors → somatosensory homunculus
63
Primary visual cortex function
occipital lobe; interprets visual stimuli
64
Broca’s area function
Motor speech area, directs muscles that are
involved in speaking, also active when we think
about what we want to say
= inferior and anterior to premotor cortex; motor speech area. Often affected in stroke. If damages person can understand but can not speak themselves
65
Wernicke’s area
| function
in temporal lobe; understanding written and spoken language. If damaged ppl can talk but don’t really make sense and often cant read as well
66
Prefrontal cortex function
= in frontal lobe; most complex region → intellect, personality, working memory, abstract thinking
67
Basal nuclei
| function
Grey matter deep within cerebrum; involved in
motor function in coordination with substantia nigra
and cerebellum
68
Corpus callosum function
White matter; tracts connecting both hemispheres
69
important areas of diencephalon
Thalamus
Hypothalamus
Pituitary gland
Pineal gland
70
important areas of brain stem
Midbrain with
substantia nigra
Pons
Medulla oblongata and
pyramids
71
important areas of cerebellum
Arbor vitae
| Peduncles
72
impotant ventricles of brain
lateral, third, forth
73
function of thalamus
Relay station for all information coming into the
| cortex; sorted, edited and integrated
74
function of hypothalamus
Regulates homeostasis (temp, sleep, food, etc.)
75
function of piuitary gland
Releases hormones to control endocrine system
76
function of pineal gland
Secretes melatonin which induces sleep
77
function of midbrain with substantia nigra
White matter (pyramidal tracts) and some nuclei,
e.g. substantia nigra; involved in reflexes (startle
and visual) and RAS; substantia nigra produces
dopamine; exit point of cranial nerves II, III, IV
ps Note: RAS = reticular activation system
78
pons function
White matter, some nuclei, respiratory control, exit
| point of cranial nerves
79
what activates reticular activation system
Increasing the amount of sensory input will activate the RAS (reticular activation system). The
more different stimuli that will be processed in various brain regions, the more effective this is.
Here you have skin sensation from the open window (wind and cold), auditory stimuli (music) and
activated taste receptors (cold water).
However, sleep can override the RAS, particularly if you are sleep deprived, so this is not always
working.
80
medulla oblongata and pyramids function
Top part of spinal cord; white matter (pyramidal
tracts in the pyramids); nuclei that are part of RAS;
cardiovascular and respiratory control; vomiting
and swallowing centre; sneeze and cough
reflexes; exit point of cranial nerves
81
abor vitae function
Distinctive pattern of grey and white matter;
cerebellum fine tunes motor function together with
basal nuclei and substantia nigra; also makes
“blueprints” for movement patterns
82
peduncles function
Sensory and motor fibres; unlike in the cerebral
| cortex, they don’t cross over
83
brain ventricles function
Produce and store CSF
• 3 and 4th are connected, and central canal reaches all the way down the spinal cord
• Openings where csf gets into meninges
84
Explain how cerebrospinal fluid is formed and describe its movement.
Made by filtration in choroid plexuses in the ventricles; circulates through ventricles and in
subarachnoid space; lateral ventricles → third ventricle → fourth ventricle → through apertures
into subarachnoid space and also into central canal along the spinal cord
85
WHERE ARE THESE STRUCTURES ON A DIAGRAM of brain
* pre- and postcentral gyri
* Different lobes
* Basal nuclei
* Thalamus, hypothalamus
* Pituitary and pineal glands
* Midbrain (superior and inferior colliculi), pons, medulla
* Cerebellum, arbor vitae
* Ventricles
* Corpus callosum
* Cranial nerves I and II
86
LIMBIC SYSTEM location and FUNCTION
Various brain parts are involved, especially deep cerebral areas and parts of the diencephalon,
e.g. hippocampus, amygdala and other nuclei. This functional system regulates emotional
behaviour, such as reaction to stress or threats, aggression, etc. It is closely linked to the
olfactory (smell) areas.
i
87
RETICULAR ACTIVATION SYSTEM FUNCTION
responsible for ALERTNESS AND WAKEFULNESS
• The more inpulses and stimuli you have to more this will be activated
• Some of the stimuli are visual, auditory, tough temperature
88
list sleep stages
5 stages
• REM sleep- rapid eye movement sleep, stage where brain is incredibly active, often dream, eyes move rapidly but brain is actually paralyzed
* Cycle every 90 min, from REM to deep sleep stages back up to REM the further we progress in the night the less deep we go. In the end we just go down to stage 2
* The deep sleep stages 3 and 4 are when the long term consolidation of facts happen and higher up in rem is when the memory consolidation of physical skills happen
breif:
REM sleep = rapid eye movement, often coincides with dreaming, high brain activity and muscles
paralysed
Non-REM stages 3 and 4 are deep sleep, showing delta waves
89
STRUCTURE OF MULTIPOLAR NEURON DRAW
MULTIPOLAR NEURON DRAW
90
ecg function
electric activity of the brain has four distinct patterns (= waves)
91
ecg function
electric activity of the brain has four distinct patterns (= waves)
• Brain electric activity can be measured by electrodes
• Encaphiliac electrogram’
92
.Name three factors that can enhance transfer of information from short-term into long-term
memory.
Practice and rehearsing
Being excited about the new information/task and having positive feelings
Being able to associate new information with previously learned facts and skills
Sleep enhances memory consolidation
93
how are neurotransmitters removed from the synaptic cleft?
They can be pumped back into presynaptic terminals (e.g. serotonin), broken down by enzymes
(e.g. Ach) or diffuse away
94
Describe the release and action of neurotransmitters.
Neurotransmitters are stored in vesicles in the axon terminals. Ca2+ entering the axon due to an
AP causes the vesicles to fuse with the presynaptic cell membrane and release them into the
synaptic cleft.
They diffuse across and bind to receptors at the postsynaptic cell membrane. This triggers a
graded potential which can either lead to or prevent an AP.
95
The presence of what ion inside the cell causes the synaptic vesicles to fuse with the
membrane?
Ca2+
96
What channels in the presynaptic neuron open up in response to an action potential?
Voltage-gated Ca2+ channels
97
What happens to the membrane potential during the repolarisation phase of the action
potential, and what causes this change?
The membrane potential returns back to the resting membrane charge of -70mV. This is due to
the opening of voltage-gated K+ channels, which leads to K+ leaving the cell. At the same time,
Na+ channels close.
Need to know: An AP is caused by changes to the electric charge of the cell membrane of the
neuron. Resting membrane potential is -70mV (caused by K+
leaking out of the cell and the work
of the Na+
/K+ pump that maintains more Na+ outside and more K+
inside the cell). Opening of Na+
channels causes Na+
influx into the cell = depolarisation up to +30mV and then opening of K+
channels that causes K+
leaving the cell (repolarisation). The depolarisation and repolarisation is
the AP.
98
what are the brain waves that can be detected by ecg
* Alpha waves- eyes closed relaxed
* Beta- when alert
theta waves- common in children
* Delta- when asleep
* Measured in hertz, how many peaks in one second
99
define transduction
the stimulus energy gets converted into a graded potential.
100
Describe the pathway for a sensory (afferent) stimulus from the receptor to the primary
sensory cortex
First order neuron: Receptor = mechano-, thermo-, photo-, chemoreceptors or nociceptor →
distal branch of sensory neuron via peripheral and then spinal nerve (cell body is in dorsal root
ganglion) → proximal branch of neuron via dorsal root into dorsal horn
Second order neuron: Interneuron in dorsal horn → crosses over to the opposite side and axon
goes all the way to thalamus
Third order neuron: Cell body in thalamus → primary sensory cortex and other higher centres
(photoreceptor would send information to primary visual centre)
101
. Describe the motor (efferent) pathway from the primary motor cortex to a muscle fibre
Upper motor neuron: Cell bodies in primary motor area (pyramid cells) → most axons cross over
to opposite side in medulla and go down spinal cord
Lower motor neuron: Cell body ventral horn → ventral root into spinal nerve → peripheral nerve
(and often via a plexus) → muscle fibre
102
typical ascending tract function
```
Sensory, i.e. pressure, touch,
temperature, pain, etc.
Afferent, i.e. transmitting
stimuli from the periphery and
internal organs to the CNS
```
103
typical ascending tract number of neurons
Three (first, second and third
| order)
104
typical ascending tract origin
Receptors (distal branch of
first order neuron, cell body in
dorsal root ganglion) on body
surface, muscles or in organs
105
typical ascending tract termination
Primary sensory cortex, some
| in cerebellum
106
typical ascending tract, where does it cross over (decussate)?
Spinal level, i.e. same level
where first order neuron
enters the spinal cord
107
typical ascending tract examples of tracts
Spinothalamic,
| spinocerebellar
108
typical decending tract function
```
Motor, both skeletal and smooth
muscle fibres
Efferent, i.e. sending impulses
from CNS to skeletal muscles,
smooth muscles in organs and
blood vessels
```
109
typical decending tract number of neurons
Two (upper and lower)
110
typical decending tract origin
Primary motor cortex in precentral gyrus, basal nuclei and
| cerebellum
111
typical decending tract termination
Neuromuscular junction or
synapses on smooth muscle
fibres
112
typical decending tract, where does it cross over?
In medulla, but some tracts
| don’t cross over
113
typical decending tract examples of tracts
Pyramidal, extrapyramidal
114
nerve function
* Are a bundle of axons
* PNS (CNS has tracts)
* Cranial or spinal
* Most are Mixed, carryingsensory (afferent) or motor (efferent)
* Innervate skin and muscles = somatic nerves or internal organs = visceral
* Cell bodies of sensory neurons are located in the dorsal root ganglia
* Cell bodies of motor neurons are in the CNS, apart from autonomic efferent fibres (will discuss next week)
115
What types of receptors do you know?
• Types
Mechano → touch, pressure (including baroreceptors that measure BP), vibration, stretch
Thermo → temperature changes
Photo → respond to light (retina in the eye)
Chemo → blood chemistry (pH), taste, smell
Nociceptors → pain
Exteroceptors → sensations from the outside environment can be combined eg. Externoreceptor that’s also a mechanoreceptor
Interoceptors → visceroceptors in organs and blood vessels can be combined too
Proprioceptors → muscles, tendons, ligaments, joints also can be combined
• Types
Non-encapsulated → free nerve endings, stimulus transmitted via C fibres; temperature, pressure, pain (also A fibres) , proprioception; e.g. Merkel cells in skin, hair follicles
Encapsulated → terminals of sensory fibres are in a connective tissue capsule; mainly mechanoreceptors; e.g. muscle spindle, Meissner corpuscle in skin
Special senses → complex sensory organs composed of different receptors, e.g. eye, ear, smell, taste
116
anatomy of the spinal cord/ nerves
* 7 cervical, 12 thoracic, 5 lumbar, 4-5 sacral vertebrae
* Spinal nerves exit below the vertebrae
* All exit just junder the vertebrae from C2 onwards
* C1 spinal nerves exit above
* In cervical and thoracic area level of spinal cord is pretty much the level of the adjacent vertebrae ( where its running through that vertebrae)
* exit is almost horizontal, but the further down you go the more of an angle it is and the longer the nerves get ( as spinal cord is shorter than the veretebral colum)
* 31 pairs of spinal nerves
117
anatomy of spine ( cross section )
* Butterfly shape is grey matter surrounded by white matter
* Tracts are in white matter
* Cell bodies in grey matter
* Meninges visabe above white matter. Dura outside arachnoid and pia innermost
* Once we leave our vertebrae though the intervertebral foramen past we are in the PNS
* Ganglion bunch of cell bodies in PNS
* Subarachnoid space and central canal would have CSF
* Dorsal area/horns/back is sensory
* Ventral/horns frontal area is motor
* Can see epidural and subdural space
* Epidural- above dura
* Subdural space- have pierced the dura
VIEW DIAGRAM
118
DIFFERENCE BETEEN AFFERENT AND EFFERENT
afferent- ascending towards brain
| efferent- decending away from brain
119
Definition pain, tolerance and threshold
pain- highly unpleasant physical sensation caused by illness or injury
Threshold = the intensity of a stimulus that will be perceived as pain (not just pressure or
temperature). This is the same for every person
Tolerance = how pain is interpreted, perceived and tolerated. This varies from person to person and also
in different situations.
120
What is a spinal nerve and what is its function (think of the types of axons it contains)? What does it become?
...
121
```
List the main influences of the ANS on the
• heart
• lungs
• pupils
• digestion
• urinary output
• blood vessels (arterioles)
• sweat glands
• metabolism
```
SYMPATHETIC
- INCREASE METABOLISM, MENTAL ALETNESS, RESPIRATION AND SILATE AIRWAYS, HEARTRATE AND BP
-DECREASE DIGESTION AND URINE OUTPUT, ACTIVATE SWEATGLANDS AND CONTROL BLOOD VESSLES
PARASYMPATHETIC
- decrease metabolism, heartrate and bp
- increase salivary and digestive, gut motility and blood flow, urine output and defectation
-constrict airways
122
What is the difference between a sensory receptor and a receptor for a neurotransmitter
...
123
what are the brains asssociation areas
areas that interpret various stimuli from all senses; compare to previous experiences; assist with motor response to those stimuli; evaluate emotional reactions to stimuli (especially smell)
124
what does csf do
* Brain floats in it → reduces weight and cushions
* Made by filtration in choroid plexuses in the ventricles
* Composition similar to plasma, but has less protein, Ca2+ and K+; more Na+, Cl- and H+
* About 150mL, replaced every 8h, 500mL produced daily
* Circulates through ventricles and in subarachnoid space
* Exchanges between CSF and ECF of brain tissue regulate both re fluid and electrolyte content
125
special brain functions
* Limbic system – emotional regulation
* Reticular activation system (RAS) – alertness and wakefulness
* Memory – formation and storage, long term and short term (= working) memory
* EEG – electric activity of the brain has four distinct patterns (= waves)
* Sleep – REM (= rapid eye movement) and non-REM stages
126
how does memory formation occur
* Just know we start of with short term some of which can be turned into long term memory
* Factors can increase liklihood we can change from short term to long term ( rehersal, excitement, associating new data with stored data)
* Sleep also importanat for memory consolidated
* Declaritive memories- new facts normally get consolidated in deep sleep phases, procedural memorie- new motor skills cosolidated in REM sleep, emotional memory often linked to smell and music
127
types of neuron fibres
* Diameter and thickness determines speed of impulse
* Group A = thick, myelinated, very fast (mainly somatic sensory and motor)
* Group B = smaller diameter, myelinated, slower than A fibres (mainly visceral somatic, ANS, some skin receptors)
* Group C = small diameter, non-myelinated, slow conduction of impulse (mainly visceral somatic, ANS, some skin receptors)
128
structure of nerve
* Structrure of nrve
* Looks similar to muscle
* Individual axons (nerve fibres)
* Fibres surrounded by endoneurium
* Several fibres make a fascicle surrounded by perineurium
* Several fascicles together with some blood vessels are surrounded by epineurium make up the nerve
