Central nervous system Flashcards
when does the Cns form in fetal development
beginning of 3rd week
when does the neural plate and neural crest form
day 23
what does the neural plate become
the neural tubal and the CNS
what does the neural crest become
the PNS
what happens on day 28
forebrain mid brain and hindbrain are formed
what happens on week 6 or day 42
forebrain becomes the cerebrum and the diencephalon
midbrain stays as is
hindbrain becomes cerebellum, pons, medulla oblongata
how many distinctive regions is the brain split up in
3
forebrain
cerebellum
brainstem
what does the cerebrum consist of in the forebrain
basal nuclei and cerebral cortex
what does the diencephalon consist of in the forebrain
hypothalamus and thalamus
what is the cerebellum consist of
cerebro
spino
vestibo
what does the brainstem consist of
midbrain
pons
medulla oblongata
how many spinal nerves is the spinal cord divided into
31 spinal nerves
where do afferent neurone do ?
carries information to the CNS
Where do efferent neurones do ?
carry information away from the CNS to effector organ
which neutron is most abundant
interneuron
where is interneuron present
only present within CNS
what provides metabolic support for neurones
glial cells
how many kinds of glial cells are there in the PNS
2 kinds
1) schwann cells
2) satellite cells
what do schwann cells do ?
they produce myelinated fibre
also support the PNS
what do satellite cells do ?
they secrete a capsule that supports the cell bodies of the neurones in the pns
how many kinds of glial cells are there in the CNS
4 kinds
1) astrocytes
2) oligodendrocytes
3) microglia
4) ependymal cells
what do astrocytes do ?
-means star
-form blood brain barrier
-is a tight junction between blood and CNS
-provides nutrition
how does the astrocyte form tight junctions
by sending foot processes that secrete paracrine signals that promote tight junction formation
what do oligodendrocytes do ?
they form myelin in the CNS
(is equivalent to schwann cells in the PNS)
what are microglia
-tiny glue cells
-are scavengers will eat any harmful bacteria and get rid of it
-they remain quiet until activated
what happens if microglia become overactive or overzealous
begin to destroy neurones and are most likely involved with dementia alzheimers, HIV and multiple sclerosis
what happens if glial cells are misbehaving
causes glioblastoma or tumour of the brain which is not curable and causes death
what are microglia equivalent to in the immune system
phagocytes
what do ependymal cells do
-most common cells that line the cavities of the CNS and form the lumen
-line cavities of CNS called ventricles
-act as neural stem cells such as in the hippocampus of the brain which generates new neurones
what do ependymal cells secrete
cerebro spinal fluid
what does cerebrospinal fluid do ?
keeps our brain and tissue safe by providing chemical and physical protection
what protects the CNS
1) cranium
2) meninges
3) cerebrospinal fluid
what are the 3 layers of meninges
1) dura matter
2) arachnid matter
3) pia matter
what does the dura matter do ?
takes used things from the brain
what does the arachnoid matter form
cobb webb like shape
what is pia matter
its the innermost layer of the meninges
brings in all the food and requirements for the neurones.
what produces CSF
and which ventricles
ependymal cells
3 and 4 ventricle
how many times a day is cerebrospinal fluid made and how much
- 3 times a day
-120/125 ml
how does csf reduce weight
by buoyancy
shock absorber learn
go back to text book
where is the bbb completely absent
the vomitting centre in the brain and hypothalamus
what makes up 80% of total brain weight
cerebrum
what is the outer surface of the cerebrum convoluted with ?
sulcus or shallow grooves ( sulci for plural)
why is there sulci
increase surface area for neurones can fit into there
what divides the two main lobes in the cerebrum
central sulcus
what are the frontal and partial lobe called ?
higher cortex
what does the corpus colosseum do ?
connects the left and right hemisphere
what is the corpus colleum referred to as ?
information super highway
how many layers of grey matter is the cerebrum divided into
6 regions
how many layers of white matter does the cerebrum have ?and what is it
1 layer
they are myelinated axons leaving the tissue
what does occipital lobe do
all vision
temporal
all hearing
parental lobe
sensory
frontal lobe
ability to speak and elaboration of though
what is between frontal lobe and parietal lobe
central sulcus a deep invagination
what causes Parkinson’s disease
lack od dopamine
how are Parkinson’s patients treated
L dopa passes the BBB through transporters
what does homunculus mean and how many region is there ?
little man
2 regions
1) somatosensory cortex
2) primary motor cortex
describe the somatosensory cortex in the homunculus
-body is upside down
-hands
-face
-tongue
-genitals
-touch, pressure, temp propioception
describe the primary motor cortex in the homunculus
fingers thumb lips tongue
lateral dominance
left and right dominant
left dominant what do they excel in
-dominate in verbal skills
-math
-analytical
-fine detail
-thinkers
-right hand 95 percent of the time
right dominate what do they excel in
-non verbal skills
-excel in spatial skills
-philosophy
-artists
-creators
-left handed 5
how you understand language is what area
wernickes area
how u speak and form words is what area
brocas area
what is damaged and what is it called if u can understand the language but cannot speak
brocas area is damaged and is called expressive aphasia
what happens if wernickes area is damaged
called receptive aphasia and cannot understand or receive language
what is the basal nuclei or basal ganglia
collection of cell bodies
what do basal nuclei do ?
they coordinate motor activity by suppressing unwanted activity
and govern muscle tone
what do basal nuclei form
a loop is formed from the basal nuclei to the thalamus to the higher motor cortex then back to the basal nuclei
what does loss of basal ganglia cause
loss of dopamine which results in parkinsons disease
symptoms of loss of basal ganglia
resting tremors
reptilian stare
stooped posture
shuffling when walking
what can drug use do to basal nuclei
will destroy it by destroying synaptic junctions
what happens with huntington disease
genetic disorder
lose ur basal nuclei
motor coordination is lost
results in twitching
progressive
no cure
bed ridden
only live till 30s
also loss of dopamine
tourettes syndrom and OCD are linked to what
basal nuclei dysfunction or loss
what does the thalamus form
a relay station
what does thalamus do
crude awareness of everything
stimuli of special interest (parent and child)
site of sensory processing
which area is most
involved in regulating internal environments
hypothalamus
what does hypothalamus do
controls homeostatic functions
forms crucial link between nervous and endocrine system
flight or fight response
food intake
temperature control system
is less than 1% of total brain tissue
what is catecholamine
flight or fight response
what does the pineal gland do
controls circadian rhythms
how does the pineal gland control our circadian rhythms
by secreting a hormone called melatonin
how many parts does the pituitary gland obtain
2 parts
anterior pituitary gland and posterior pituitary gland
what happens in the anterior pituitary gland
responsible for the formation of the gonads inmates and females gametes // also called gonadtropic action
what does the anterior pituitary govern
male and female hormones
what is responsible for the command of prolactin secretion and milk production
anterior pituitary gland
what does the posterior pituitary gland secrete and what is it involved in
secretes oxytocin and is involved in milk ejection and lactation (helps mother bond to baby)
what other hormones does the posterior pituitary gland secrete and what does it do
vasopressin
it is an anti diuretic that governs our urine formation that governs our kidney and blood pressure
what is the cerebellums second name
second brain
what does spin-cerebellum do
enhances muscle ton
coordinated skill
voluntary movements
what does cerebrocerebellum do
plays a role in planning and initiating voluntary activity by providing input to cortical motor areas
procedural memories are stored here an example is dancing
what does the vestibulocerebllum do
involved with balance
waiting balance in inner ea and equilibrium
also involved with eye movements
what is the brainstem considered and what does it do
considered primitive and performs life sustaining activities
where is the site of the 12 pairs of cranial nerves written in roman numerals
brain stem
except for number 10 which is involved in the heart
where is the site of reticular activating system
brain stem
what does the reticular activating system do
blood pressure
arousal
stretch reflexes
pain modulation
what is the midbrain involved in
eye reflexes
auditory reflexes
ear functions
what is the pons involved in
a bridge between medulla and midbrain
breathing
what is the medulla involved in
controls blood pressure
breathing
swallowing
vomiting
what do the 12 cranial nerves provide
neck and head
what is the limbic system responsible for
emotion behaviour
what does the limbic system consist of
cingulate gyrus
amygdala
hippocampus
fornix
what is cingulate gyrus involved in
emotions expressed in gestures
what is the fornix purpose
purpose is unclear
memory loss may be associated with this area if fornix was removed
what is the amygdala involved in
fear
anger
distress
involved in flight or fight
what does the amygdala trigger
the hypothalamus
how many distinct regions is there of amygdala
22
what is the role of the hippocampus
memory is stored here
episodic declarative memory
what where when
new neurones are produced here
what area is lost in alzheimers
hippocampus
what is the spinal cord covered by
vertebral column
what does the spinal cord form
dermatomes
what is the shape of the spinal cord
slender
cylinder of nervous tissues
what is the spinal cord made of
central lumen and definitive region
where does whit matter of the spinal cord carry information
to and from the brain
how many regions is the grey matter divided into
3 regions
dorsal horn(afferent neurons )
lateral horn (autonomic efferent neurons)
ventral horn(somatic efferent neurons)
what do afferent neurones do
they form a collection of cell bodies
what does lateral horn do
provides the periphery with all the efferent neurones
what does the ventral horn do
sufficient to the somatic systems of the body
types of reflexes
1) innate
2)learned
what is babinskis positive
toes will flare out 0 to 24 month
