module 6 Flashcards
what does the sympathetic nervous system do
Prepares the body for heightened activity.
Involved in flight or flight
increases cardiovascular and respiratory activity:
Shuts blood to skeletal muscle and heart
Reduces blood flow to nonessential organs
Dilates bronchioles
causes liver to release glucose
Increases sweat gland activity
Dilates pupil (to allow distance vision)
Decreases digestive functions and urination
what does the parasympathetic nervous system do
stimulates abdominal visceral activity, conserves energy=rest and digest
Directs digestions, diuresis/micturition, defecation
Decreases cardiovascular and respiratory activity
Constricts pupils (to allow near vision)
Eg, relaxing and reading after a meal
in what ways are the somatic and autonomic nervous system different
Neural (efferent) pathways
Effectors
Organ response
Neurotransmitters
whats the somatic nervous system do
Conducts motor impulses from primary motor cortex to skeletal muscles
what motor pathways does the somatic nervous system involve
upper motor neurons
Lower motor neurone
whats somatic output control
voluntary movement Somatic reflexes (involuntary movement)
whats the automomic nervous system do
- Conducts motor impulses from hypothalamus to cardiac and smooth muscle and glands.
- May involves brain steam nuclei (medulla oblongata)
- Influences by cerebral cortex and limbic system.
what motor pathways does the autonomic nervous system include
CNS interneuron
Pre ganglionic neuron
Post ganglionic neuron
what autonomic output controls
involuntary activities
visceral organ function
Glandular activity
Visceral reflexes.
whats the somatic motor pathway
Efforts (skeletal muscle) innervated by a LMN that exits the CNS via a:
Spinal nerve: LMN cell body located in a motor nucleus of anterior grey horn, Axon exits the spinal cord via a ventral root of a spinal nerve
Cranial nerves: LMN cell body located in a brainstem nucleus
LMN heavily myeilated
LMN releases acetylcholine (ACh) at the synapse with the effector
ACh= always excitatory, resulting in a skeletal muscle contradicti
whats the preganglionic neuron autonomic motor pathway
cell body in CNS- motor nueclei in brain stem or lateral gray matter (parasympathetic) of spinal cord, or lateral gray horn (sympathetic) of spinal cord.
Lightly myelinated axon exits CNS via a cranial or spinal nerve and synapses with postganglionic neuron in a ganglion
Releases ACh, always excitatory (always results in an action potential in postganglionic neuron)
whats the post ganglionic neuron autonomie motor pathway
cell body located in a ganglion (near CNS or near effector)
Unmyelinated axon exits the ganglion to innervate the effector
Neurtranimiters release:
Sympathetic neurons eg noradrenalin
Parasympic neurons eg achtocholine
similarities of sympathetic and parasympathetic
serve many of the same organs
Preganglionic neurons: thing, lightly myelinated, release ACh
Postganglionic neurons: unmylinated
Presence of ganglia
whats the difference between sympathetic and parasympathetic ns
both divisions do not innervate all organs
Site of exit from the CNS
Length of the axons
Location of the ganglia
whats the parasympathetic division also called
cranioscaral division
whats the parasympathetic division neurons
Preganglionic neurons arise from opposite ends of the CNS; brain and sacral region of spinal cord
Ganglia located close to or within target organ
Preganglionic axon=long
postganglionic= short
whats the parasympathetic cranial pathway
Pregangionic axons leave motor nuclei of brain stem via cranial nerves
CN III=oculmotor nerve, controls diameter of pupil
CN VII= facial verve, salivary, nasal and lacrimal glands, tears
**CN X= viragos nerve, neck, thoracic and abdominal visceral organs. ONLY one that extends from the neck region.
whats the parasympathetic scram pathway
Preganglionic neuons:
cell body in motor nuclei of lateral gray matter(not horns)
Axon exists via ventral root of the spinal nerves associated with the sacral spinal cord.
Postganglionic neurons innervate:
pelvic organs (balddre, reproductive organs)
Distal portion of large intestine
whats the sympathetic division also called
thoracolumbar division
whats the neurons in the sympathetic division
All preganglionic fibres arise within spinal cord segments T1 to L2. Exist spinal cord via spinal nerves Ganglia located close to spinal cord Preganglionic axon= short Postganglionic axon= long
whats the sympathetic trunk
chain of 23 ganglia connected by fibres to form sympathetic trunk, flanks both sides of the vertebral column, extends from neck to pelvis
wheres the adrenal medulla located
inner region of the adrenal gland
whats the adrenal medulla part in the sympathetic response
Sympathetic preganglionic fibres:
Synapse with endocrine cells within the adrenal medulla
Release ACh which stimulate these endocrine cells to secrete adrenaline (A) and noradrenaline (NA) to interstitial fluid to the blood. **ONCE IN BLOODSTREAM the neurotransmitters are known as hormones
A and NA move through vassal system —-> effect any cell bearing receipts for these hormones
** therefore enhances and prolongs the sympathetic response
whats the visceral reflexes
automatic motor response to a stimulus to act to preserve homeostasis
Reflex may be facilitated or inhibited by higher centres (eg hypothalamus)
EXAMPLES:
Baroreceptor reflex, controls blood pressure
Pupillary (consensual light) reflex
whats the steps of an excitatory postsynaptic potential (ESPS)
- Neurotransmitter binds to receptors on postsynaptic membrane.
- Opens gated ion channels
- Graded depolarisation
- Postsynaptic membrane is closer to threshold and thus trigger an action potential
= excitatory postsynaptic potential.
(brings it closer to threshold therefore bringing it closer to action potential and therefore making it more likely to reach action potential.
whats the steps of the inhibitory postsynaptic potential (IPSP)
- Neurtoranmittter binds receptors onpostsynaptic membrane
- Open gated ion channels
- Graded hyperpolarisation
- Postsynaptic membrane is further from threshold
= inhibitory postsynaptic potential.
(moves further away from threshold therefore further away from action potential and therefore making it less likely for an action potential to occur.
what do EPSP and IPSP result from
the opening of different gated ion channels upon neurotransmitter binding.
anything involved in acetylcholine is called a
cholingeric something. Eg cholinergic neuron, receptors, synapse etc.
whats anything involved in noradrenaline or adrenaline called
adrenergic something eg. (adrenergic receptors, adgrengic synapse)
whats a cholinergic receptors
receptors that bind ACh
whats two types of cholinergic receptors
Nictontic cholinergic receptos- always excitatory (causes EPSP), located all ANS postganglionic neurons, skeletal muscles.
Muscarinic cholingeric receptors- excitatory (causes EPSP) or inhibitory (causes IPSP), located all parasympathetic target organs.
whats an adrenergic receptors
receptors that bind NA or A
whats an agonists do
mimic the action of the neurotransmitter
whats an antagonist do
bind the receptors and block the action of the neurotransmitter
whats acetylcholine do
-Skeletal muscle control (motor control outside CNS)
within the CNS secreted in the cerebral cortex (cognitioin), hippocampus (memory) and brainstem (consciousness).
Low levels of ACh in Alzheimers patients, drug that inhibits breakdown of ACH help.
whats the main categories of neurotransmitters
acetylcholine
biogenic amines
amino acids
neuropeptides
whats examples of biogenic amines
NA, dopamine and serotonin
whats biogenic amines
emotional behaviour
Imbalances associated with mental illness
Regulate biological clock
whats noradrenalin involved in
reward and pleasure
low level associated with depression
Involved in stress and attention
Release enhanced by amphetamines, DANGEROUS the longer you take them the less you make of your own.
whats dopamine involved in
Stimulates reward and pleasure Role in motivation for reward behaviour Release enhanced by amptheamines Reuptake blocked by cocaine High levels associated with schizophrenia Deficient in Parkinsons disease.
whats serotonin involved in
Mood regulation, sleep, appetite
deficit association with depression
Blocking reuptake relieves anxiety and depression
Acitivtyenhaced by ecstasy or dark chocolate
Increases feelings of confidence, does damage neurons and impairs cognition.
whats examples of Amino acids
GABA and gluatamate
whats GABA involved in
main inhibitory neurotransmitter in brain
Help regulate sleep/wakefulness
Involved in motor control
Inhibitory effects increased by alcohol, impaired motor coordination
GABA blockers induce convulsions (rapid, repeated muscle contraction and relaxation)
whats glutamate involved in
cant cross blood brain barrier
Common in food
Involved in learning and memory
Excessive release, excitotoxicity (kills surrounding neurons) dying neurons release glutamate with kill surrounding neurons eg alzheimers disease
whats examples of neuropeptides
substance P and endorphins
whats substance P
produced by damaged tissue
Stimulates nociceptors (pain receptors)
Mediates pain transmission to the CNS
whats endorphins
induces endorphines (brain) and enkephalins (spinal cord)
Inhibits perception of pain in the CNS (protective response)
Natural opiates- chemically similar to morphine (agonist)
whats the difference between the preganglionic and postganglionic neurons in the sympathetic and parasympathetic diviosn
sympathetic- pre=short post=long
parasympathetic pre=long post=short
