Physiology Exam II review Flashcards
1
Q
Upper motor neuron uses what NT
A
Glutamate
2
Q
Lower motor neuron uses what NT
A
Acetycholine
3
Q
Renshaw cells -type of cell, location, receives branches from
A
Inhibitory cells in anterior horns of spinal cord
Receive branches from alpha motor neurons
4
Q
Sensory fiber conduction rate from fastest-slowest
A
C fibers - fastest
A-d fibers
A-a or A-b
5
Q
Nociceptors and thermoreceptors are related to what fibers
A
C or A-d
6
Q
Muscle spindle is made up of what and innervated by
A
3-12 intrafusal fibers innervated by small gamma motor neurons
7
Q
Central region of spindle functions as
A
Sensory receptor- no contractile fibers
8
Q
Nuclear bag fibers
A
Detect rate of change in muscle length
Innervated by group Ia afferents and dynamic y efferents
9
Q
Nuclear chain fibers
A
Detect static change in muscle length
Innervated by group II afferents and static y efferents
10
Q
Stimulation of muscle spindle sensory fibers results in
A
Stimulation of a-motor neurons, contraction
11
Q
Golgi tendon organ detects what
A
Muscle tension (contraction or stretching)
12
Q
Golgi tendon organ circuitry
A
Type Ib afferent–> Inhibitory interneuron–> anterior motor neuron
13
Q
Reciprocal inhibition
A
Ex. When flexing arm to move hand away from hot surface, biceps are excited and triceps inhibited
14
Q
Premotor/supplementary motor areas
A
Create plan for movement- for more complex movements
Premotor- develops motor image
Supplementary - Programs motor sequence, mental rehearsal
15
Q
Medial activation system of UMN innervate
A
Postural and girdle muscles
16
Q
Lateral activation system of UMN innervates
A
Distal muscles used for fine movement
17
Q
Nonspecific activating system of UMN
A
Facilitate local reflex arcs
18
Q
Corticospinal/pyramidal tract origin
A
Primary motor cortex
Premotor cortex
Somatosensory area
19
Q
Corticospinal/pyramidal tract pathway
A
Site of origin--> Internal capsule--> Medullary pyramids--> (most) Cross in lower medulla--> Lateral columns of spinal cord
20
Q
Lateral corticospinal tract
A
Fibers that have crossed in medulla
Supplies all levels of spinal cord
21
Q
Anterior corticospinal tract
A
Uncrossed fibers (eventually cross near LMN) Supply neck/upper limbs
22
Q
Corticospinal tract functions
A
Add speed and agility to conscious movements, especially hands
Provides high degree of motor control
23
Q
Giant pyramidal (Betz) cells are located
A
In motor cortex
24
Q
Corticospinal muscle tract lesions cause
A
Reduced muscle tone
Clumsiness
Weakness
Not complete paralysis (only if both pyramidal and extrapyramidal systems are involved)
25
Corticobulbar tract
UMN of cranial nerves- innervate face/head neck
| -Terminate in reticular formation
26
Fibers from _____ and _____ synapse in the _______ portion of the red nucleus
Primary motor cortex; corticospinal tract
| Magnocellular portion
27
Stimulation of red nucleus results in
Stimulation of flexors
| Inhibition of extensors
28
Vestibulospinal tract receives info from
Cranial nerve VIII (vestibular nerve)
29
Vestibulospinal tract synapses with ____ which supply ___
LMN supplying extensors
| -maintain upright posture
30
Components of vestibulospinal tract
Utricle w/macula on horizontal plane (upright)
Saccule w/macula on vertical plane (lying down)
Semicircular canals
31
Macula contains
Calcium carbonate crystals, cilia etc...
32
Cerebellum functions
Planning, timing, adjusting muscle movements -mainly when they have to be rapid
Not essential for locomotion
33
Cerebellar vermis zone
Location for control functions of muscle movements of body, neck, shoulders, hips
34
Intermediate zone of cerebellum
Muscle contractions in distal portions of upper/lower limbs
35
Lateral zone of cerebellum
Planning of sequential motor movements w/cerebral cortex
36
Dentate, emboliform, globose nuclei (intracerebellar) lesions result in
Extremity ataxia
37
Fastigial nuclei (intracerebellar) lesions result in
Trunk ataxia
38
Granular layer
Innermost layer of cerebellar cortex
| Golgi II cells, glomeruli, mossy fibers
39
Purkinje cell layer
Middle layer of cerebellar cortex
| Purkinje cells
40
Molecular layer
Outermost layer of cerebellar cortex
| Stellate cells, basket cells, purkinje dendrites, granule cell axons
41
Granular cells form
Parallel fibers in cortex
42
Golgi cells project from and to
Parallel fibers to granular cell bodies
43
Basket cells project from and to
Parallel fibers to purkinje axon hillock (lateral inhibition)
44
Stellate cells project from and to
Parallel fibers to purkinje dendrites (lateral inhibition)
45
Purkinje cells
Project to intracerebellar nuclei
| -They are ONLY output from cerebellar cortex, and always inhibitory
46
Climbing fibers
Afferent from cerebellar cortex- cause complex spikes
| Play role in motor learning, condition purkinje cells
47
Mossy fibers
Afferent from cerebellar cortex
| Make simple spikes
48
Vestibulocerebellum
Control of balance and eye movements
| Contains flocculonodular lobes
49
Loss of flocculonodular lobes results in
Extreme disturbance of equilibrium and postural movements
50
Changes that occur when cerebellum is removed
Movements are slow to develop and turn off, force is weak
51
Vestibulocerebellum syndrome
Progressive genetic disease of flocculonodular lobe
Nystagmus
Vertigo, tinnitus
52
Spinocerebellum
Vermis/intermediate zone
Receives info from motor cortex and red nucleus
Sends corrections back to them via thalamus
53
Cerebrocerebellum
Lateral parts of hemispheres
Receives corticopontocerebellar projections
Coordination of speech
54
Corticopontocerebellar tract
Major link b/w cortex and cerebellum
| Lesions result in weakness
55
Vestibulocerebellar tract terminates
In flocculonodular lobes
56
Reticulocerebellar tract terminates
In vermis
57
What tracts form the mossy fibers
Corticopontocerebellar
Vestibulocerebellar
Reticulocerebellar
Spinocerebellar
58
Axons from what form climbing fibers
Olivocerebellar tract
59
Cerebelloreticular tract begins
Fastigial nuclei --> reticular
60
Cerebellothalamocortical and cerebellorubral tracts begin
Dentate, emboliform, globose nuclei
61
Basal nuclei functions
Plan/execute motor commands w/cerebral cortex
| Modulate thalamic output to motor cortex
62
Basal nuclei putamen circuit (direct pathway)
```
Cerebral cortex (+Ach)-->
Putamen (-GABA)-->
Internal Globus pallidus (IGP) (-GABA)-->
Thalamic relay nuclei (+Glutamate)-->
Primary motor cortex
```
63
Dopamine D2 receptors vs D1 receptors
D2 inhibitory
| D1 excitatory
64
Lesions in globus pallidus
Inability to maintain postural support
| Spontaneous movements of hand/arm etc- ethetosis
65
Lesions in subthalamic nuclei
Sudden flailing movements of an entire limb- hemiballismus
66
Lesions in striatum (putamen)
Flickering movements of hands/face/elsewhere- Chorea
| -Occurs w/huntingtons
67
Lesions in substantia niagra
Caused by destruction of dopaminergic neurons
Parkinsons
Tremors
68
Dopamine effect on direct and indirect pathway
Dopamine inhibits the indirect pathway and excites the direct pathway
69
Direct (putamen) pathway function
Excitatory
| Subconscious execution of learned movements
70
Indirect (caudate) pathway function
Inhibitory
| Planning of sequential/parallel motor patterns
71
Where can you find neurons that are directly sensitive to chemical/physical variables (temperature etc)
Hypothalamus
72
Brain areas affecting body temp
Anterior preoptic hypothalamus
73
Warm sensitive neurons
30% of neurons in APH
| Activate neurons in paraventricular nucleus and lateral hypothalamus -- Parasympathetic
74
Cold sensitive neurons
5% of neurons in APH
| Activate neurons in posterior hypothalamus --Sympathetic
75
What is the brain area involved in shivering
Posterior hypothalamus
76
Posterior hypothalamus normally inhibited by _____, when activated it sends signals to
Inhibited by heat center in APH
| Sends signals to activate a/y-motor neurons in lateral horns
77
IL-1/prostaglandins effect on fever
Increases it
78
Aspirin effect on fever
Decreases by reducing prostaglandin synthesis
79
Active transport of glucose occurs via ___ and where
Sodium glucose cotransport
| GI tract, renal tubules
80
End products of Citric acid cycle
16 hydrogens
2 ATP
4 CO2
81
Increased blood glucose leads to
Increased osmotic pressure
Increased urine output
Damage to tissues/vessels
82
When 2 electrons pass through for oxidative phosphorylation, how much ATP is produced
3 ATP
83
ATP formed per glucose molecule per cycle
| efficiency is %
```
Glycolysis-2
CAC-2
OP-34
38 total per glucose
66% efficiency
```
84
Pentose phosphate pathway
Synthesis of triglycerides from glucose
| Uses NADPH
85
Uptake of triglycerides
They are first digested into monoglycerides/fatty acid
Intestinal cells resynthesize them into triglycerides that enter lymph as chylomicrons
-Bile salts form micelles w/lipids for absorption
86
Lipoprotein lipase
Adipose/heart/skeletal muscle
| Hydrolyzes triglyceride/chylomicron to fatty acids and glycerol
87
VLDL
High concentration of triglycerides, moderate amount of phospholipids and cholesterol
Transports lipids from liver to adipose
88
LDL
High concentration cholesterol, moderate amount of phospholipids
89
HDL
High concentration protein, low cholesterol/fatty acid
90
What happens to ketones
Converted to acetyl CoA
91
Conditions favoring ketosis
Starvation
Diabetes
Fatty diet
92
Ornithine cycle mitochondrial steps
Ammonia + CO2--> Carbamoyl phosphate
| Carbamoyl phosphate + Ornithine--> Citrulline
93
Ornithine cycle cytoplasmic steps
Citrulline + aspartate--> arginosuccinate
Arginosuccinate --> arginine + fumarate
Arginine--> urea + ornithine
Fumarate can enter CAC
94
What is the best known stimuli for increasing rate of thyroid stimulating hormone
Cold
95
Thyroxine and metabolic rate
Increases metabolic rate
96
Testosterone and metabolic rate
Can increase 10-15% due to anabolic effect of increasing muscle mass
97
Malnutrition and metabolic rate
Reduces it significantly
98
Propulsive movements
Contractile ring occurs at point of stimulation in gut and can move orally or rectally (usually dies out orally)
Myenteric plexus is needed
99
Mixing movements
Can be caused by peristaltic contractions themselves
100
What cells generate slow waves and what are they
Cells of Cajal
- slow waves are not action potentials;they spread through gap junctions and occur spontaneously
- set maximum frequency of contraction
101
Spike potentials
Action potentials when GI membrane > +40mV
| Opens calcium-sodium channels in GI smooth muscle
102
Reflexes integrated entirely within gut wall- function
Much of GI secretion
Peristalsis
Mixing contractions
Local inhibitory
103
Reflexes from gut to prevertebral sympathetic and back to gut
Long distance signals
Evacuation of colon
Inhibit stomach motility/secretion
Empty ileal contents
104
Gastrin activation/actions
Eating/Phe/Trp
Stimulates gastric acid secretion by parietal cells
Stimulates mucosal growth
Inhibited by acid (negative feedback)
105
Zollinger-Ellison syndrome
Gastrin secreting non-b cell tumors of pancreas
106
What secretes cholecystokinin and what is its action
I-cells of small intestine
Controls feedback of duodenum
Pancreas functions
Inhibit appetite
107
What secretes secretin and what are functions
S cells of small intestine
| Stimulates pepsin, inhibits gastric acid secretion
108
GIP secreted by, action
Only GI hormone secreted in response to fat/carb/protein
K cells of duodenum/jejunum
Stimulates insulin release, inhibits gastric acid secretion
109
Motilin secreted by/actions
M-cells of duodenum/jejunum
Stimulates gastric motility
Secreted during fasting
110
Saliva secretion regulated by
Mostly parasympathetic, but also sympathetic- both result in increased saliva
Cranial nerves VII and IX
111
Parasympathetic saliva receptor/ second messengers
Cholinergic
| IP3 and Calcium
112
Sympathetic saliva receptor/ second messengers
B-adrenergic
| cAMP
113
Direct parasympathetic stimulation of H+
CN X innervates parietal cells to release H+
| Ach is NT
114
Indirect parasympathetic stimulation of H+
CN X innervates G cells
G cells secrete gastrin which stimulates H+ secretion
GRP is NT
115
Histamine secretion action
Stimulates H+ secretion by activating parietal cells
116
Somatostatin secreted by/functions
Delta cells of pancreas
Inhibits secretion of insulin, glucagon, gastrin
Decreases motility/secretion/absorption of GI tract
117
Crypts of Lieberkuhn
Goblet cells
Enterocytes-absorptive
Paneth cells-antimicrobial
Enteroendocrine cells-peptide hormones
