Structure and function of the NS- Spina bifida Flashcards
split into
autonomic (sum and para) and somatic
Spinal nerves are part of the
somatic nervous system
how many pairs of spinal nerves
31- innovate different parts of your body
–> made up of sensory (afferent) and motor (efferent) neurons
afferent
sensory
efferent
motor
Autonomic NS is made up of
sympathetic and parasympathetic NS
brain stem
autonomic NS
sympathetic innovation
fight or flight- thoracolumbar
parasympathetic
- rest and digest- craniosacrel
autonomic NT
noradrenaline or adrenaline
what innovates thoracic region
sympathetic
what innovates neck and bottom part of the back
parasympathetic
somatic
motor function
main features of the somatic nervous system
- always 1 efferent motor neurone from CNS to target organ
- cell body in the CNS
- NT released from terminal bouton- alway ACh in somatic
NT in somatic NS is always
ACh
receptor on target organ in somatic NS is always
nicotinic - inotropic receptor (Na+ channel- ligand gated)
bouton=
presynaptic knob
do somatic neurones have pre-and post ganglionic neurones
no- just one efferent motor neurone
sympathetic neurones structure:
1 short preganglionic neurone and a longer post ganglion neurone.
sympathetic neurones always release … from preganglionic neurones
ACh- always an ACh nicotinic receptor
sympathetic postganglionic always have an
adrenoreceptor (noradrenaline released from postgwanglonic neurone terminal bouton)-
adrenoreceptor found on sympathetic post ganglionic neurone is
metabotropic- GPCR- longer response
heart- sympathetic
B1 adrenergic receptor (GalphaS)- ionotropy, chemotrophy and luistropy
luistropy
rate of mycardio relaxation
bronchiole- sympathetic
B2 adrengeric receptor (GalphaS)- relaxes
parasympathetic neurone structure
2 neurones cranial and sacral
- 1 long preganglionic neurone from CNS
- 1 short postganglionic neurone- ACh released
receptor on post ganglionic parasympathetic neurone is
nicotinic ACh
ganglia in parasympathetic neurone is found
near effector organ
what kind of receptor is found on parasympathetic target organ
muscarinic acetyl choline receptors- metabotropic- GPCR
M2 heart- relaxation
GalphaI
M3 exocrine glands
GalphaQ
GPCR
7 transmembrane
3 subunits-heterotrimeric, alpha, beta, gamma
GalphaS
activates adenylate cyclase- increase in cAM- activates PKA
GalphaI
inhibits adenylate cycle- less cAMP
GbetagammaO
activates K_ channels and inhibits Ca2+ channels
GalphaO
activates phospholipase C: increase in IP3
dermatomes
areas of the skin innovated by the 1 spinal nevers
C1 has no
dermatomes
CN X
vagus nerve (heart, stomach, small and large intestine and bronchiole tree)
CN III
eyes
CN VII
face
CN IX
mouth, taste, salivation
S2-S4
parasympathetic
-pelvic splanchnic
T1-L3 (thoracic region)
sympathetic
peeing is
PARASYMPATHETIC
peeing uses the… NS
somatic
therapeutics for urinary incontinence
muscarininc M3 antagonists aka Anticholinergics
anticholingerics
muscarinic M3 antagonistics
external sphincter is under
voluntary somatic control
sympathetic nervous system … the bladder
relaxes
-detrsor muscle and this constricts the internal sphincter and stops us weeing- adrenergic receptors B2/B3
therapeutics for those who struggle to urinate
- alpha1- adrenoreceptors antagonists- relaxes internal sphincter- helps micturition if blockages e.g. enlarged prostate
- B3- adrenoreceptor agonist- enhances bladder agonists
micturition
peeing
innervation of bladder is
parasympathetic
parasympathetic nerves which innervate the bladder
pelvic, S2-3
bladder filling and emptying cycle
1) bladder fills–> detrusor muscle relax
2_ urethral sphincter contracts causing first desire to wee (bladder half full)
3) sympathetic innervation causes urination to be voluntarily inhibited until time and place is right
4) urination occurs when due to parasympathetic innervation the urethral sphincter relaxes
5) the detrusor muscles contract
how many ml in bladder
200-400ml
which receptors signal to S2, S3
stretch
sphincters
controls urine flow and maintains continence between voidings
is micturition a reflex
in infants- just a spinal reflex
in adults-spinal reflex, along with higher control
resting potential of membrane
-70mV- highly permeable to K+ and Cl-
refractory period
short period after an AP, in which another AP will not be generated- discrete
key points of AP
all or nothing, discrete unidirection
process of an AP
1) resting potential maintained by leak K+ current- highly permeable to K+ and Cl-
2) depolarisation- when membrane potential reaches the threshold, botlage gated Na+ are activated
3) more voltage gated Na+ open- AP
4) rapid depolarisation- Na+ channels inactivated and slower voltage gated K+ channels activated
5) voltage gated K+ channels can use an overshoot- hyperpolarisation
grooves in the brain
sulci, gyri and fissures
sulci
shallow grooves found on the cerebral cortex
gyri
ridges found on the cerebral cortex
fissures
deep grooves on the cerebral cortex
what protests the brain
meninges, skull and csf
meninges
three layers dura mater, arachnid mater an dpi mater
csf
cerebrospinal fluid- produced in the ventricles which surround and cushion the brain
primitive brain parts
midbrain, pons, medulla oblongata
midbrain
motor movement, such as eye movement and some auditory and visual processing
pons
connects upper and lower parts of the brain
medulla oblongata
sustains basic reflex functions such as breathing, swallowing and heart rate
frontal lobe
voluntary movement, emotional regulation, planning, reasoning, problem solving
parietal
integrating sensory information: tough pressure, temp and pain
occipital
processing visual info
temporal
hearing, language recognition and memory formation
limbic
emotion, behaviour, motivation, LTM and olfaction
grey matter
outer layer of the brain made up neuronal cell bodies
white matter
inner layer the brain made up of myelinated axons
corpus callosum
largest of several bundles of nerve fibres- connects the left and right hemispheres of the brain
basal ganglia
islands of great matter deep within the brain
limbic system is made up of
hypothalamus, amygdala, thalamus and hippocampus
hypothalamus
responsible for functions such as monitoring body temp, nutrient levels, water-salt balance, blood flow, hormone lies and sleep wake cycle
amygdala
memory processing, decision making and emotional rections
thalamus
regulation of consciousness, sleep and alertness
hippocamus
short term memory
what is a biomarker
a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes or pharmacological response
-clinical assessment
characteristic of biomarker
safe and easy to use, cost effective, modifiable treatment, consistent across gender and ethnic groups, rapid return of results
uses of biomarkers
- to detect severity or presence of a disease
- to assess effectiveness of particular therapies
common biomarkers
proteins or peptides, antibodies, cell types, metabolites, lipids, hormones, enzyme levels, introduced substance
excitation contraction coupling
1) Motor Neuron releases ACh at neuromuscular junction and binds to receptors
2) Na+ moves into the cell initiating a action potential
3) Action potential propagates down into the T-tubule and alters the conformation of the DHP receptor
4) DHP is mechanically linked to RYR therefor when the shape of DHP changes RYR opens releasing Ca2+ from the sarcoplasmic reticulum into the cytoplasm
5) Ca2+ binds to troponin causing Actin-Myosin binding
6) Myosin heads move together in the power stroke
7) Actin filament slides towards centre of sarcomere
myotomes
the group of muscles that a single spinal nerve innervates
-used in diagnosis to test motor function of the nerve root. determine if there is a problem on the spinal cord
dermatomes
an area of skin in which sensory nerves derive from a single spinal nerve root
what is the NMJ
where a motor neurone and muscle can connect and an AP is translated into a muscle contraction.
action potential to muscle contraction
1) An action potential travels down a motor neurones bouton stimulating the release of ACh into a synaptic cleft, shared by sarcolemma (outer membrane containing myofibrils).
2) The sarcolemma is in turn stimulated by ACh.
3) This creates an action potential which travels along the sarcolemma, into T tubules.
4) Within these T tubules the action potential then stimulates RyR (voltage dependent channels)
5) The RyR channels send a signal through the terminal cisternae to the sarcoplasmic reticulum (SR) which surround the myofibrils.
6) With the use ATP the signal causes Ca2+ release from calsequestrins within the SR. The Ca2+ is released into the sarcomere.
7) Resulting in a muscle contraction.
what occurs after powerstroke
calcium is pumped against conc gradient from cytosol back into the reticulum, with the help of Ca2+ ATPase. As conc of Ca2_ decreases troponin releases the calcium molecule. This causes tropomyosin to slide back intuit its original position- blocking the actin active sites. As the myosin heads uncouple from the actin molecule the muscle fibres relax to their original position with the help of elastic fibres found in the sarcomere and surrounding tissue
power stroke process
calcium ions bids tot he troponin molecules forming a troponin cas2+ complex thats conformation change causes tropomyosin to shift- exposing myosin binding sites on the actin units.
Myosin heads bind to the actin site and through the energy provided by the hydrolysis of ATP, perform the power stroke, pulling the actin filaments in to slide past eachother- resulting in the contraction of muscle
somatic ns is part of the
peripheral nervous system
Somatic ns is associated with
voluntary control of body movements via skeletal muscles
somatic nervous system consists of
afferent and efferent nerves
PNS is made up of somatic and
autonomic
Afferent
sensory
sensory neurones
responsible for relaying sensation from the body to the CCNS
-receptor picks up stimulus and from the environment and that stimulus is transformed into an electrical signal- single axon directly to the spinal cord
efferent nerves
motor
motor neurones
responsible for sending out direction from the CNS to the body. Dendrites and cell body of motor nerone originate in the spinal cord. Once the signal has been pick up by dendrites it sends it through the axon- through the PNS and to the axon terminal. Somatic neurone ends at effete muscle, where NT initiates muscle contraction
why is regeneration restricted in somatic cells
damage t the spinal cord rarely heals as the injured nerve fails to regenerate. The regrowth of their long were fibres is hindered by scar tissues
31 pairs of
spinal nerves (somatic)
12 pairs of
cranial nerves (somatic)
