physio exam 2 review ppt Flashcards
what layer in the motor cortex are the pyramidal cells located
5th layer
what layers have the input signals in the motor cortex
2-4
what type of neurons are the anterior motor neurons in the spinal cord
alpha motor neurons
what are interneurons responsible for
most of spinal cord integrative function (capable of spontaneous activity)
where are renshaw cells located
anterior horns of spinal cord
where do renshaw cells receive collateral branches from
alpha motor neurons
what type of inhibition occurs when renshaw cells transmit inhibitory signals to surrounding motor neurons
lateral inhibition. enhances fluidity of limb movement
what type of inhibition occurs when renshaw cells transmit inhibitory signals to the same motor neuron
recurrent inhibition
what are muscle spindles innervated by
small gamma motor neurons (group 2 afferents)
what type of change do nuclear bags detect
rate of change in muscle length (dynamic change)
what type of change do nuclear chain fibers detect
static change
what are nuclear bag fibers innervated by
1a afferents and dynamic gamma efferents
what are nuclear chain fibers innervated by
group 2 afferents and static gamma efferents
describe dynamic stretch reflex
signals transmitted from primary nerve endings and elicited by rapid stretch or unstretch (opposes sudden changes in muscle length)
describe static reflex
transmitted by both primary and secondary endings and causes degree of muscle contraction to remain relatively constant
what does the muscle spindle over do for its function
prevents jerkiness of body movements (damping)
what does muscle stretch do to firing rate of type 1a afferent fibers
increases firing rate
describe flexor/withdrawal
flexion on ipsilateral side; extension on contralateral side
what motor areas generate a plan for movement
premotor and supplementary motor cortices
what creates the “motor image” of the total muscle movement that is to be performed
anterior part of premotor cortex
what part of the cortex programs complex motor sequences and is responsible for mental rehearsal for a movement
supplementary motor cortex
describe the signal from the posterior motor cortex
to primary motor cortex, the basal nuclei and thalamus, then back to primary motor cortex
define pyramidal system
tracks that pass through medullary pyramids
where do upper motor neurons originate for the pyramidal system
motor cortices
describe the medial activation system of the pyramidal system
innervate postural and girdle muscles
describe the lateral activation system of the pyramidal system
associated with distally located muscles used for fine movements
describe the nonspecific activating system of the pyramidal system
facilitate local reflex arcs
where does the rubrospinal tract originate
red nucleus
where does the rubrospinal tract decussate
midbrain
where does the rubrospinal tract descend
lateral funiculus
what is the function of the rubrospinal tract
closed related to cerebellar function
what occurs if there are lesions in the rubrospinal tract
impairment of distal arm and hand movement. intention tremors
where does the vestibulospinal tract descend
anterior funiculus
what does the vestibulospinal tract synapse with
LMNs to extensor muscles
what is the vestibulospinal tract primarily involved in
maintenance of upright posture
where does the reticulospinal tract descend
anterior portion of lateral funiculus
what is the reticulospinal tract thought to do
mediate larger movements of trunk and limbs that do not require balance or fine movements of upper limbs
describe the utricle
located in horizontal position and plays role in determining orientation of head when head is upright
describe the saccule
located in a vertical plane and signals head orientation when a person is lying down
what occurs when the stereo cilia of the macula bend toward the kinocilium
depolarization and excitation
what occurs when the sterocilia of the macula bend away from the kinocicium
hyper polarization and closure of channels
what divides the 2 hemispheres of the cerebellum
vermis
what is the oldest lobe of the cerebellum
flocculonodular
what is the role of the vermis (besides dividing hemispheres)
location for control functions for muscle movements of the axial body, neck, shoulders and hips
what is the role of the intermediate zone of the cerebellum
concerned with controlling muscle contractions in the distal portions of the upper and lower limbs, especially hands, feet, fingers and toes
what is the role of the lateral zone of the cerebellum
associated with cerebral cortex with planning of sequential motor movements
what are the transversely arranged narrow gyri located in the cortex of the cerebellum
folia
what type of ataxia occurs when lesions to dentate, emboli form and globose nuclei
extremity ataxia
where do the dentate nuclei, emboli form nuclei and globose nuclei project to
red nucleus
what are the dentate nuclei, emboli form nuclei and globose nuclei related to
limb musculature and fine manipulative movement
what type of ataxia occurs when there are lesions to the fastigial nuclei
trunk ataxia
where do the fibers of the fastigial nuclei project
reticular formation and vestibular nuclei
what are fastigial nuclei related to
postural activity and limb movements via reticulospinal and vestibulospinal tracts
what are the only excitatory cells in the cerebellar cortex
granular cells
where do the golgi cells, basket cells, and stellate cells project
golgi to granular cell bodies, basket to purkinje axon hillock and stellate to purkinje dendrites
what is the only output cell for the cerebellar cortex
purkinje cell
where do climbing fibers originate
medullary olives
what do climbing fibers play a role in
motor learning
where do mossy fibers originate
multiple centers in the brainstem and spinal cord
what do climbing fibers synapse with
purkinje cells
where do mossy fibers synapse
on granule cells in glomeruli
what type of spikes to climbing fibers have
complex
what type of spikes do mossy fibers have
simple
what is the neurotransmitter that purkinje cell axons use
GABA
what do purkinje cell axons modulate
output of cerebellum and provides synergy
what does the vestibulocerebellum consist of
flocculonodular lobes and vermis
what occurs if there is a loss of flocculonodular lobes
extreme disturbance of equilibrium and postural movements
what disorder occurs when movements overshoot their mark continuously
dysmetria
what disorder is described as the inability to perform rapid alternative movements
dysdiadochokinesia
what disorder is failure of progression in talking
dysarthria
what disorder is described as tremors of the eyeball
cerebellar nystagmus
what is the prince role of basal nuclei
work with corticospinal system to modulate thalamic output to the motor cortex to plan and execute smooth muscle movements
what is the putamen circuit used for
subconscious execution of learned patterns of movement
what is the caudate circuit used for
cognitive planning of sequential and parallel motor patterns
what neurons are destroyed in huntington’s disease
GABA
what neurotransmitter is used to go from the substantia nigra to the caudate nucleus and putamen
dopamine
what neuron transmitter is used to go from the caudate nucleus and putamen to the globes pallidus and substantial nigra
GABA
what neurotransmitter is used to go from the cortex to the caudate nucleus and putamen
acetylcholine
what happens to motor activity in huntington’s disease
it increases because the indirect pathway no longer has inhibitory influence on direct pathway
what are stimulating factors for sweating
stimulation of anterior hypothalamus-pre-optic area, cholinergic sympathetic nerve fibers and circulating epinephrine and norepinephrine
what are the principle areas of the brain that affect body temperature
anterior hypothalamic/pre-optic area and pre-optic area
what happens immediately after heating the anterior hypothalamic/pre-optic area
dilation of skin blood vessels over the entire body, profuse sweating over the entire body and inhibition of excess heat production
what are some causative factors for fevers
brain abnormalities, surgery in region of hypothalamus, prostaglandins and liposaccharide toxins
how does aspirin decrease the set point temperature
inhibiting cyclooxygenase which results in decrease production of prostaglandins
where do slow waves originate
interstitial cells of Cajal
what do slow waves excite
the appearance of intermittent spike potentials
when do spike potentials occur automatically
when resting membrane potential of GI smooth muscle becomes more positive than -40mv
what inhibits the secretion of gastrin
acid from stomach and somatostatin
what stimulates gastrin secretion
small peptides and aa in stomach lumen, dissension of stomach, vagal stimulation
where is gastrin secreted
G cells of antrum, duodenum and jejunum
what pathology is association with issues with gastrin
Zollinger-ellison syndrome
what stimulates CCK secretion
small peptides and aa, fatty acids and monoglycerides
what is the site of secretion for CCK
I cells of duodenum, jejunum and ileum
what stimulates the secretion of secretin
acid and fat in lumen of duodenum
what is the site of secretion for secretin
S cells of the duodenum, jejunum and ileum
what stimulates bicarbonate secretion
secretin
what is the only hormone released in release to protein, fat and carb
GIP
what is the site of secretion for K cells
duodenum and jejunum
what does GIP stimulate
insulin release
what is the major hormonal control feed back of the duodenum
CCK
composition fo saliva
high potassium ion and bicarbonate concentrations
when are potassium levels in saliva low
when it has the highest flow rate
where does the first stage of salivary secretion occur
acini
what does the first stage of salivary secretion contain
ptyalin (alpha-amylase)
where does the second stage of salivary secretion occur
salivary ducts
what is the secretion product of gastric secretions of parietal cells
HCl and intrinsic factor
what does the CN X innervate in the direct pathway of gastric secretions
parietal cells
what receptor does the direct pathway for gastric secretions use
Ach and muscarinic receptor
what does CN X innervate in the indirect gastric secretions
G cells
what is the neurotransmitter of the indirect pathway for gastric secretion
GRP
what is the second messenger on parietal cell for gastrin stimulation
IP3/ Ca++
what is the second messenger for histamine stimulation
cAMP
what does somatostatin inhibit
gastric H2 secretions
what is the indirect way that somatostatic inhibits gastric H2 secretions
inhibits release of histamine and gastrin
what does somatostatin bind to in the direct pathway for inhibition of gastric H2 secretions
binds to receptors on parietal cell that are coupled to adenyl cyclase via a Gi protein
what is the digestive enzyme for carbs
pancreatic amylase
what is the digest enzymes for fats
pancreatic lipase, cholesterol esterase, phospholipase
how does acetylcholien stimulate enzyme secretion
by acinar cells and potentates effect of secretin
what is the second messenger for cholecystokinin
IP3 and increased intracellular Ca++
what is the second messenger for secretin
cAMP
how is fructose absorbed in the small intestine
facilitated diffusion
where can phosphorylation of glucose be reversed
liver, renal and intestinal cells
what are the end products of the Krebs cycle
16 hydrogens, 2 TP, 4 CO2
where does oxidative phosphorylation occur
mitochondrial cristae
what is special about cytochrome A3
it can give up 2 electrons to oxygen and is located on inner membrane
what is the maximum efficiency for calories/mole glucose
66 percent
what is the pentose phosphate pathway mostly used for
synthesis of fats and other substances
how are chylomicrons transported to the venous system
via thoracic duct
what tissues removes chylomicrons
adipose tissue, skeletal muscle and heart
what lipoprotein (s) is synthesized in intestinal cells
chylomicrons
describe the concentrations for VLDLs
high concentrations of triglycerides and moderate amounts of cholesterol and phospholipids
describe the concentrations for LDLs
high concentrations of cholesterol and moderate concentration of phospholipids
describe the concentrations for HDLs
high concentrations of proteins and low concentration of cholesterol and fatty acids
what are the basic causes of atherosclerosis
increased LDLs and familial hypocholesterolemia (defective LDL receptors)
