Exam 1 Week 2 Flashcards
what is the function of the ANS
to regulate homeostasis of circulation, respiration, digestion, metabolism, secretions, body temperature and reproduction
where do the afferents of the ANS come from
viscera
where do the efferents of the ANS go to
glands, organs, smooth muscle and cardiac muscle
efferents from the ANS go in one of two paths
sympathetic or parasympathetic
where are the mechanoreceptors for the ANS located
pressure: baroreceptors in the aorta, carotid sinus and the lungs.
stretch: in the veins, bladder and intestines.
where are the ANS chemoreceptors
in the carotid and aortic bodies (O2), medulla (H ions and CO2), hypothalamus (blood glucose and electrolytes), taste buds and olfactory bulbs
where are the ANS nociceptors
in the viscera (stretch and ischemia) and arterial walls (chemicals)
where are the ANS thermoreceptors
hypothalamus: blood temp
cutaneous: external temp
afferent pathways, in the ANS, go one of two ways. what are those
the spinal cord through the dorsal root or the brainstem through the cranial nerves (7,9,10 taste and visceral)
cranial nerves send visceral information to the main visceral sensory nucleus which is the…? from here, it sends info to the…
solitary nucleus
pons, medulla, hypothalamus, thalamus and limbic system
visceral afferents synapse with the
visceral efferents (autonomic reflex) and neurons that ascend to the brainstem, hypothalamus and thalamus
visceral nocioceptive afferents connect with
somatosensory nocioceptive tract neurons (referred pain) and somatic efferents (muscle guarding)
autonomic neurons secrete three things… are they cholinergic or adrenergic
ACh (cholinergic)
NE (adrenergic)
Epi (adrenergic)
what does the medulla control
HR, respiration and vasoconstriction/dilation
what do the pons regulate
respiration
what does the hypothalamus modulate
regulates homeostasis and internal equilibrium, affects HR, RR, metabolism, water balance, digestion and body temperature
what does the thalamus regulate?
it projects signals to the limbic system
what does the limbic system modulate
emotions, mood, motivation. it will include autonomic responses, like when your anxious, your HR increases too.
efferent pathways in the ANS are 2-neuron pathways… what does this mean
preganglionic and postganglionic
what are muscarinic receptors?
CHOLINERGIC when ACh binds, the G-protein mediated response is initiates, and there is either an excitatory or inhibitory effect to regulate glands, smooth muscle and the heart
What are nicotinic receptors
CHOLINERGIC. when ACh binds, fast induction of excitatory postsynaptic potential.
when nicotine binds, what is increased
task performance and attention
what are the two cholinergic receptors
muscarinic and nicotinic
what are the three adrenergic receptors/neurons
Norepinephrine, adrenal medulla, and anything that binds NE and epi.
Norepinephrine is released by most…
sympathetic postganglionic neurons
The adrenal medulla will release Epi and NE directly into… what?
the blood
what is the function of an adrenergic receptors
bind NE and epi and have alpha and beta groups, with their own subtypes.
where are adrenergic receptors most abundant/distributed, and also distributed?
peripheral smooth muscle, and also in the heart and lungs.
what kind of adrenergic receptors are in the heart? what do they do
Beta-1.
increase HR and contractility.
what kind of adrenergic receptors are in the bronchial smooth muscle? what do they do
mainly Beta-2.
bronchial tree dilation, so it opens the airways
what kind of adrenergic receptors are in the skeletal muscle arterial walls? what do they do
alpha.
NE binds= vasoconstriction. Regulates BP
what is the general affect of Beta 1 and 2 adrenergic receptors on the body
increased HR and contractility, and bronchodilation
what is the general effect of alpha adrenergic receptors on the body
vasoconstrictor the arterial walls of smooth muscle, when NE binds, so it can help alter BP
describe the effects of the following drug blockers
alpha
B1
agonist:
B2
List some medical conditions with these.
alpha: blocks NE from binding, so no vasoconstriction, more like vasodilation, which will decrease BP
B1: when they are blocked, the HR and contractility will decrease (HBP, arrhythmia, MI.)
B2 AGONIST: will prevent the airways rom closing, due to the bronchodilation abilities. (asthma and COPD)
what are (9) functions of the sympathetic nervous system
**maintain optimal blood flow to organs. fight or flight response pupil dilation bronchodilation cardiac acceleration (HR and blood flow) digestion is inhibited piloerection glucose release is stimulated systematic vasoconstriction to control and regulate BP
body temperature is regulated in two way… how?
epi: when the adrenal medulla releases this, the byproduct is heat
sympathetics can control blood vessel diameter, sweat glands secretion and also piloerection.
what are the (10) PNS functions
**energy conservation and storage rest and digest pupil contraction (CN 3) bronchoconstriction (CN 10) decreased HR (CN 10) digestion is stimulates salivation (CN 7 and 9) lacrimation (CN 7) intestinal vasodilation sacral efferents, bowel and bladder emptying and erection
the sympathetic nervous systems targets what structures
fight or flight
muscles and structures in the body wall and cavities
what does the parasympathetic nervous system target?
structures in the body cavity, head, and sex organs
where are the pre and post ganglionic cell bodies found in the sympathetic NS
pre: in the lateral grey matter of the thoracolumbar vertebrate
post: in the sympathetic chain, or in the collateral ganglion
where are the preganglionic cell bodies and the postganglionic in parasympathetic
pre: CNs 3,7,9,10 and in pelvic splanchnic nerves
post: terminal ganglia
the sympathetic chain is what kind of ganglion
paravertebral
what are all preganglionic receptors, in both the sympathetic and parasympathetic
cholinergic, (ACh)
what are all postganglionic receptors, in both the sympathetic and parasympathetic
sympathetic: adrenergic (NE and epi)
para: cholinergic (ACh)
what is feed forward, and an example
anticipatory use of sensory information, like knowing the pavement is icy, so you change how you walk in preparation
what is feedback,
use of sensory information gathering during and after a movement, used to make corrections
what happens to somatosensation and proprioception when vision is lost
they both have to increase their activity
what is deafferentation
disrupts the position of the limbs, absence of movement.
describe what happens in the motor system
you make a decision in the anterior frontal lobe, and you start using your motor planning areas to activate the circuits you need (in the cerebellum and the basal ganglia).
then you send UMN from the brain and spinal interneurons to the LMN
and the LMN will go to the skeletal muscles
what is tone
the resistance to passive stretch
what is normal tone
we should have some resistance
what is the absence of tone
flaccidity
what is lower then normal tone and excessive tone
hypotonia and hypertonia
what is spasticity
the resistance to passive stretch that occurs with velocity. excessive movement, that is detected with moving the muscle quickly
spasticity is a result of damage to the CNS/PNS
CNS
is volitional movement a passive movement
no
what is the difference between an upper and lower motor neuron
upper: neuron that begins int he cortex, and terminates in another part of the brain or the spinal cord.
lower: begins in spinal cord and terminates in skeletal muscle
what does an UMN lesion look like
spasticity and exaggerated reflexes clonus
what does a LMN lesion look like
weakness, muscle fasciculation and atrophy
where are the LMN cell bodies located
in the ventral horn of the spinal cord
there are pools of LMN in the ventral horns. what muscles are in what pools? anterior, posterior, medial and lateral
medial: axial and proximal muscles
lateral: distal muscles
anterior: extensors
posterior: flexors
what is a motor unit
one alpha neuron and the muscle fibers it innervates
what are alpha motor neurons, compared to gamma motor neurons
alpha: large cel bodies and myelinated axons, that project to extrafusal muscle, and release enough ACh that all of the muscle fiber it innervates can contract
Gamma: medium sized axons with myelin. go to intrafusal fibers, and when it contracts, keeps the muscle taut and stretched, so that the spindles can be ready to detect changes in that stretch
if there are fewer muscle fibers per neuron, what does that mean for precision and control
it is very fine
give examples of muscles that are fast and slow twitch
fast: phasic contractions, like the GN
slow: postural muscles, like the soleus
does the C1 nerve root come out above or below the vertebrate
above
at what level does the spinal cord end
L1-2
what does the spinal cord end in, and what come after
conus medlars, cona equina and filum terminale
spinal cord blood supply comes from
1 anterior spinal artery and 2 posterior spinal arteries
what does the anterior spinal artery supply
the anterior 2/3 of the cord
the spinal branches give off what arteries
the reticular arteries and then the anterior and posterior give off medullary arteries
what is the venous drainage of the spinal cord
there are anterior and posterior longitudinal sinuses that collect from the body and around the segment
in what space are the spinal veins for drainage located
epidural
what happens if you have decreased fluid volume in the epidural space
headaches
which side has that indented commissure, the anterior or posterior
anterior
TF: as you ascend in the spinal cord towards the brainstem, you get more white matter
true, this is because of all of the ascending and descending tracts.
do spinal reflexes need the brain
no
what is the purpose of the jendrasik maneuver
this goes to the brain. increases the reflex stimulus.
what info so the reflexes provide
info about the peripheral and spinal circuits
what is a phasic reflex. describe the path
brief, like a DTR.
Ia afferent, goes to cord, synapses, then alpha motor neuron out. So it is a monosynaptic reflex
what is a tonic reflex, and when is it present
present with a UMN lesion because the reflex remains as long as the stimulus is present
describe the path of a tonic reflex
Ia and II afferents to the cord, which get multiple interneurons, which goes back to the LMN.
why, in an undamaged NS, does a sustained stretch not elicit reflexive contraction
presynaptic inhibition
with SCI, the loss of presynaptic inhibition leads to what
sustained firing of spindle endings, and therefore contraction
what is the withdraw reflex
cutaneous, noxious stimuli, so you pull your foot away from that stimulus..
how can arousal levels impact reflexes
relaxed, reflex is minor, anxious reflex is more.
what is reciprocal inhibition
you inhabit the antagonist, while the agonists contracts
what is muscle synergists
coordinated muscle actions, communications among muscles to get a task done, like hand to mouth
what do Golgi tendon organs do
tension in tendons, and goes to spinal cord by type Ib afferents.
give an example of how GTOs are involved with stance and swing phase
stance: GTO signals LMN, and extensors contract
Swing: GTO tension is less, so LMN inhibits extensors
what are central pattern generators
interneurons that activate alternating flexion and extension in the knees, required for locomotion and moving the limbs.
