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Physiology II Exam II > Physiology II Exam II Dr. A Review > Flashcards

Physiology II Exam II Dr. A Review Flashcards

0
Q

What are the types of cells associated with the spinal cord and what are their functions?

A

Sensory (afferent neurons)
Anterior motor neurons (Alpha motor): give rise to A alpha (Aa) fibers
Interneurons: 30x more than Aa neurons, small and excitable, responsible for most of spinal cord integrative functions
Renshaw cells: receive collaterals from alpha motor neurons, inhibitory signals to surrounding motor neurons, results in lateral inhibition

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1
Q

What is the integrative center for motor pathways? Where is most of motor activity initiated?

A

Spinal cord

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2
Q

What is the function of the muscle spindle?

A

Detects changes in muscle length
Central region has no contractile fibers; functions as a sensory receptor
Stretching of central region of intrafusal fiber stimulates sensory fibers
Stimulation of sensory fibers results from lengthening of entire muscle which results in contraction of ends of intrafusal fibers

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3
Q

What are the sensory and motor fibers involved in muscle spindle actions?

A

Muscle spindle has 3-12 intrafusal fibers and are innervated by small gamma motor neurons
Sensory fibers originate from central region: Ia primary fibers form auunolspiral ending, 17um, 70-120m/sec; II secondary fibers are 8 um so transmit slower

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4
Q

What are the three main components of the cerebral cortex that affect motor functions?

A

Primary motor cortex (Broadman’s Area 4)
Premotor cortex (Area 6)
Supplementary motor Area (6)

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5
Q

What is the function of the primary motor cortex?

A

Signals motor neurons to contract skeletal muscle fibers
Signals via the corticospinal (pyramidal tract)
Execution of commands is preceded by extensive processing by cerebellum and basal nuclei

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6
Q

What is the function of Premotor cortex?

A

Plans movement based on sensory and visual cues
Signals generated here cause more complex patterns of movement than the discrete pattern generated by primary motor cortex; anterior part of premotor cortex develops a motor image of the total muscle movement that is to be performed
Image in posterior motor cortex excites each successive pattern of muscle activity required to achieve image
Posterior motor cortex sends signals to: primary motor cortex–>basal nuclei and thalamus–>primary motor cortex

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7
Q

What is the function of the supplementary motor area?

A

Retrieves and coordinates memorized motor sequences

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8
Q

What is one of the major differences between sensory and motor pathways in terms of neurons involved?

A

Motor system pathway only uses 2 neurons (Upper and Lower motor neurons) whereas sensory pathways uses 3 but this doesn’t take into consideraation the interneurons (association neurons) between upper and lower motor neurons

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9
Q

What is the generalized motor pathway?

A

Descending pathway with 2 motor neurons: upper motor neurons and lower motor neurons but doesn’t take into consideration the association neurons between upper and lower motor neurons

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10
Q

What tracts make up the descending pathways?

A
  1. Corticospinal tract and corticobulbar tract (Pyramidal system)
  2. Rubrospinal tracts, vestibulospinal tracts, reticulospinal tracts (Extrapyramidal system)
    * extrapyramidal includes descending motor tracts that do NOT pass through medullary pyramids or corticobulbar tracts
    Corticospinal is split in lateral and anterior corticospinal
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11
Q

How are cells in the motor cortex organized?

A

Vertical columns; each column has 6 distinct layers

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12
Q

What are the general characteristics of the pyramidal system (corticospinal tract and corticobulbar tracts)?

A

Start with upper motor neurons which originate in the motor cortices
75-85% decussate in pyramids and form the lateral corticospinal tracts
Remainder decussate near synapse with lower motor neurons and form anterior corticospinal tracts
Most synapse with association neurons in spinal cord central gray

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13
Q

______ is made up of corticospinal fibers that have crossed in the medulla and supply all levels of the spinal cord

A

Lateral corticospinal tract

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14
Q

______ is made up of uncrossed corticospinal fibers that cross near level of synapse with LMNs and supply neck and upper limbs

A

Anterior corticospinal tract

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15
Q

Where do the corticospinal tracts originate? What is the pathway?

A

Originates in primary motor cortex, premotor cortex or somatosensory area
Pathway: Site of origin–>internal capsule–>medullary pyramids in lower medulla–>LATERAL column of spinal tract
Some fibers do not cross but continue down ipsilaterally in ventral corticospinal tract
Other fibers in from cortex pass into caudate nucleus and putamen, pass to red nucleus, pass to reticular sustance and vestibular nuclei, and large numbers of fibers pass to pontine nuclei

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16
Q

What are the functions of the ccorticospinal tract?

A

Adds speed and agility to conscious movements–especially movements of hand
Provides high degree of motor control (movement of individual fingers)

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17
Q

Corticobulbar tract

A

innervates head
Most fibers terminate in reticular formation near cranial nerve nuclei
Association neurons leave reticular formation and synapse in cranial nerve nuclei and synapse with lower motor neurons

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18
Q

Rubrospinal Tract

A

Extrapyramidal
Begins in red nucleus, decussates in midbrain, descends in lateral funiculus (column), function is closely related to cerebellar function
Lesions result in impairment of distal arm and hand movement, intention tremors (similar to cerebellar lesions)

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19
Q

Vestibulospinal Tract

A

Extrapyramidal
Orginates in vestibular nuclei-receives input from vestibular nerve CN 8
Descends in anterior funiculus column
Synapses with LMNs to extensor muscles-primary involved in maintaining upright posture

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20
Q

Reticulospinal tract

A

Extrapyramidal
Orginates in various regions of reticular formation
descends in anterior portion of lateral funiculus
Thought to mediate larger movements of trunk or fine movements of upper limbs

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21
Q

What are the components of the vestibular apparatus?

A

Urticle: Macula on horizontal plane which determines orientation of head when head is upright
Saccule: Macula on vertical plane which signals orientation of head when person is lying down
Semicircular canals

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22
Q

What is the role of calcium carbonate crystals needed for balance and equilibrium reception?

A

Each macula is covered by gelatinous layer that has many embeded calcium carbonate crystals (statoconia); macula contains 1000s of hair cells which project cilia into gelatinous layer; weight of statoconia bends cilia in direction of gravitational pull

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23
Q

Macula

A

Has 50-70 small cilia (stereocilia), has 1 large cilium (kinocilium) off set to one side; tips of stereocilia are connected together and to kinocilium; bending of cilia opens 100s of cation channels causing receptor membrane depolarization; bending of cilia in opposite direction closes channels and hyperpolarizes receptor membrane; hair cells oriented such that bending the head in different directions causes different groups of hair cells to depolarize

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24
Q

Semicircular canals

A

When head is bent forward 30 degrees
lateral ducts are horizontal,
anterior ducts are in vertical planes projecting forward and 45 degrees outward
posterior ducts are in vertical planes projecting backward and 45 degrees outward

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25
Q

Ampulla

A

Enlargement at one end of each duct
Filled along with duct with endolymph
Crista ampullaris: Small crest within each ampulla
Cupula: loose mass of gelatinous tissue on top of crista

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26
Q

How are semicircular canals related to equilibrium and balance

A

When head rotates in any direction, inertia of fluid in one or more semicircular canals stays stationary while semicircular canal rotates with head; fluid flows from duct through ampulla and causes cupula to bend to one side
Hundreds of hair cells within each cupula detect this bending and send signals via vestibular nerve

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27
Q

Tonic rate of discharge graph: What happens when you begin rotation, what happens when you stop rotation? How do hair cells respond when a semicircular canal is stimulated by onset and then stopping of rotation

A

Tonic level of discharge=100 impulses per second (0-20 sec)
When you begin rotation, the impulses per second jumps up to 400 impulses per second (rapid, sudden increase)
During rotation, impulses per second rapidly decreases back to 100 impulses per second, and then once rotation has stopped, impulses per second goes down to zero.

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28
Q

Anotomical Organization of the Cerebellum

A

Two hemispheres separated by vermis–each hemisphere divided into intermediate and lateral zone
3 lobes in cerebellum anterior to posterior: Anterior, Posterior, Flocculonodular (vestibular system)

29
Q

What is the oldest part of the cerebellum evolutionarily?

A

Flocculonodular lobe

30
Q

Vermis vs Intermediate zone vs. Lateral zone

A

Vermis: controls muscle movements of axial body, neck, shoulders, hips
Intermediate zone: controls distal part of upper and lower limbs, hands, feet, fingers and toes
Lateral zone: associated with cerebral cortex with planning sequential motor movements

31
Q

Intracerebellar nuclei: Which ones involved in trunk ataxia, which ones in extremity?

A

Dentate, emboliform, globose–lesions cause extremity ataxia; these fibers project to red nucleus and are related to limb musculature and fine manipulative movements
Fastigial nuclei–lesions cause trunk ataxia; fibers project to reticular formation and vestibular nuclei and are related to postural activity and limb movements via reticulospinal and vestibulospinal tracts

32
Q

What is the relationship of the cerebellum to other major parts of brain stem like reticular formation and vestibular nuclei?

A

?

33
Q

What is the only output from the cerebellar cortex?

A

Purkinje cells

34
Q

What are the afferent tracts to cerebellum?

A

Corticopontocerebellar
Vestibulocerebellar: ends in flocculonodular
Reticulocerebellar: ends in vermis
Spinocerebellar: dorsal and ventral, 120m/sec
All of these above tracts form mossy fibers that end on granule cells (+)
Olivocerebellar

35
Q

What are the efferent tracts of the cerebellum?

A

Cerebelloreticular
Cerebellothalamocortical
Cerebellorubral
Cerebellovestibular

36
Q

Putamen circuit

A

For subconscious execution of learned patterns of movement
Cerebral cortex–>globus pallidus–>thalamic relay nuclei (ventroanterior and ventrolateral nuclei)–>primary motor cortex (and premotor/ supplementary)
BYPASSES CAUDATE NUCLEUS

37
Q

Caudate circuit (Look at circuit diagrams–direct vs. indirect!!)

A 
For cognitive planning of sequential and parallel motor patterns
Cerebral cortex (premotor, supp, somatosensory)-->caudate nucleus-->globus pallidus (internal)-->thalamic relay nuclei (ventroanterior & ventrolateral)-->premotor and supplementary motor cortex
38
Q
  1. Dopamine (inhibitory) is the NT going between___ and ___
  2. GABA (inhibitory) is the NT going between ___ and ___
  3. Acetylchoine is the NT between ____and ___
  4. Multiple pathways from brain stem use ___ ___ and___
  5. What NT is excitatory and is involved in multiple pathways?
A
  1. substantia nigra–>caudate nucleus and putamen
  2. Caudate nucleus and putamen–>globus pallidus and substantia nigra
  3. cortex–>caudate nucleus and putamen
  4. Norepinephrine, serotonin (inhibitory), encephalin
  5. Glutamate
39
Q

Parkinsons vs. Huntington’s symptoms

A

Parkinsons: rigidity of much of musculature, involuntary tremors even at rest, difficulty in initiating movement (akinesia), postural instability, dysphagia, speech disorders, gait disturbance, fatigue
Huntingtons: flicking movement of individual muscles, progressive severe distortional movements of entire body, severe dementia, motor dysfunctions

40
Q

Pathology of Parkinson’s vs. Huntington’s in relation to basal nuclei

A

Parkinson results from lesions in substantia nigra; destruction of pars compacta of substantia nigra that sends dopaminergic fibers to caudate nucleus and putamen
Huntington is caused lesions in putamen (chorea)–loss of most of cell bodies of GABA secreting neurons of caudate nucleus and putamen and of Ach neurons in other parts of the brain

41
Q

What is the difference between conduction, convection and radiation?

A

Conduction: Kinetic energy of the molecules of skin transferred to air if air is colder than skin
Convection: Removal of heat from body by convection air currents
Radiation: Loss in the form of infrared heat rays radiated by all objects not at absolute zero; if temp of body is greater than ambient temp, more heat is radiated from the body than to the body

42
Q

What are the functions of the hypothalamus and the pre-optic area in terms of controlling heat?

A

Anterior hypothalmic pre-optic area and pro-optic area are principal areas of the brain affect body temperature. Anterior pre-optic area contains both heat sensitive and cold sensitive neurons. Heat sensitive neurons increase firing rate 2-10x in response to 10degree increase in body temp. Cold sensitive neurons increase firing rate when temp falls.
Heating the pre-optic area causes dilation of skin blood vessels over entire body, profuse sweating over entire body, inhibition of excess heat production

43
Q

Set point for thermal control:

  1. What is the critical body core temp?
  2. How does this core temp relate to heat loss and heat production?
  3. What is the set-point of the temp control mechanism?
A
  1. 37.1 C (98.8 F)
  2. Heat loss is greater at temp above 37.1, and heat production is greater at temp below this temp
  3. Set point=level at which sweating begins or shivering begins in order to return to critical core body temp
44
Q

Set-point for thermal control

  1. What is the feedback gain (and how is it calculated) of the temp control system and how does it compare to that of other biological control systems?
  2. What are physiological mechanisms that alter the critical set point?
A
  1. (change in env temp/change in body core tmep)-1.0=(28/1)-1=27
  2. Mechanisms that alter set point: skin temperature changes
45
Q

What is the role of the thyroid gland in controlling heat production?

A

Increased thyroxine output increases the rate of cellular metabolism and therefore increases heat production

46
Q

How is the chemical composition of sweat different if you’re sweating profusely vs. insensibly?

A

Precursor secretion: composition is similar to that of plasma without protiens: Na–142 mEq/L and Cl—104 mEq/L
Rapid/strong stimulation of sweat glands: Large amounts of precursor secretion formed, ducts reabsorb only about half the sodium chloride and concentrations of sodium and chloride ions are about 50-60 mEq/L and little water is reabsorbed

47
Q

Layers of gut tube from outer to inner

A

Serosa, Longitudinal smooth muscle layer, myenteric plexus (of Auerbach), Circular smooth muscle layer, Meissner’s plexus (submucosal plexus), mucosa

48
Q

Inhibitory effect of enterogastric nervous reflexes:

A

Reflexes occur directly from duodenum through enteric nervous system of gut wall
Reflexes occur through extrinsic nerves that go to prevertebral ganglia and then back through inhibitory sympathetic nerve fibers to stomach
Reflexes may occur via vagus nerves back to brainstem

49
Q

Interstitial cells of cajal are associated with what function?

A

Pacemaker activity for smooth muscle cells

50
Q

Voluntary stage of swallowing ends at what location?

A

Pharynx

51
Q

What is the sequence of layers making up the gut wall from inside (lumen) towards outside?

A

Mucosa, lamina propria, submucosa, circular muscle layer

52
Q

The submucosal (meissners) plexus is primarily responsible for regulating intestinal smooth muscle. True or False?

A

False. There are 2 plexuses: Myenteric plexus and Meissner’s. Myenteric controls regulation of intestinal smooth muscle. Meissners is closer to mucosa.

53
Q

In the smooth musculature of the gut wall spike waves occur automatically when the resting membrane potential of the smooth muscle becomes more positive than about -40mV. True or False?

A

TRUE

Could be phrased a diff way–know -40mV.

54
Q

Pancreatic Secretions

A

Digestive enzymes for proteins: trypsin, chymotrypsin and carboxypeptidase; trypsin inhibitor secreted by glandular cells; necessary to prevent action of trypsin on pancreatic tissues themselves
Digestive enzymes for carbs: pancreatic amylase
Digestive enzymes for fat: pancreatic lipase, cholestrol esterase, phospholipase
Bicarbonate ions: HCO3- and Na+ are actively transported into duct lumen; hydrogen ions are exchanged for sodium ions

55
Q

Hormonal factors that control feedback from the duodenum

A

CCK is the most potent; other possible inhibitors include secretin and GIP

56
Q

Motor functions of the stomach

A

Storage of large amounts of food
Mixing food with gastric secretions (Mixing occurs in upper stomach wall every 15-20 sec) and move toward antrum; mixing waves replaced by peristaltic waves that drive food toward pylorus; thickness of circular muscle layer in pylorus is 50-100% greater than elsewhere in stomach (pyloric sphincter)
Slow emptying of chyme into SI: stretching of stomach wall due to increased food volume promotes increased emptying of stomach due to local myenteric reflexes in wall

57
Q

Regulation of pancreatic secretion

A

Acid from stomach releases secretin from wall of duodenum; fats and amino acids cause release of CCK
Secretin and CCK absorbed into blood stream
Vagal stimulation releases enzymes into acini
Secretin causes copious secretion of pancreatic fluid and bicarbonate; CCK causes secretion of enzymes

58
Q

Nerve mechanisms for controlling gastric secretion

A

Gastic secretions: Chief cells
Pepsinogen is stimulated by Ach from vagus nerves (parasympathetic and enteric nervous system) or gastric enteric nervous plexus–response to acid in stomach

59
Q

Parasympathetic regulation of salivary system (3 different levels of feedback pathways)

A
  1. 3 main groups of salivary glands: parotid, submandibular and sublingual glands which have similar innervation pattern.
  2. There are 2 main cranial nerves involved in this. In parotid gland, we have glossopharyngeal and facial nerve. Facial nerve has portion that is passing through the middle ear (called chordae tympani);
  3. motor innervation to submandibular and sublingual gland is via the facial nerve. Motor innervation to parotid gland is via glossopharyngeal nerve. Both come from the superior and inferior salivatory nuclei–superior goes to submandibular and sublingual; the inferior goes to parotid. Glossopharyngeal activity also comes from tongue (sensory neurons) and they end up in tractus solitarius and have feedback to motor nucleus to salivary glands so when food hits tongue, it sets up feedback loop to cause saliva to flow. Because this is parasympathetic, facial and glossopharyngeal are cranial nerves that carry parasympathetic functions. We have ganglia (submandibular ganglia for submandibular and sublingual gland and the otic gland for parotid gland)–these represent the area synapse between the pre-ganglionic fiber and the post ganglionic fibers
60
Q

How does glucose and other sugars get into cells? What keeps them in cells? What happens to them once they are in cells?

A

Transport of glucose into cells can occur via sodium-glucose co transport or via facilitated transport
Presence of insulin increases glucose transport x10
Phosphorylation of glucose prevents diffusion out of cell
Phosphorylation can be reversed in liver, renal and intestinal cells

61
Q

Role of phosphorylase and phosphatase in metabolic pathways

A

?

62
Q
  1. Role of CO2 fiven off in pathway?

2. Oxidative phosphorylation and hydrogen ions

A
  1. ?
  2. Hydrogen removed in pairs; one member becomes hydrogen ion, the other combines with NAD+–>NADH
    Fate of electrons removed from H ions=enter ETC–important for energy calculations
63
Q

Pentose Phosphate Pathway: what does it do? Where does it occur?

A

Cyclical pathway where one molecule of glucose is metabolized for each revolution of cycle–for every 6 glucose that enter, five are resynthesized
Pathway used for synthesis of fats and other substances
H generated from this pathway are bound to NADP+ instead of NAD+
Occurs in the cytosol
NADP+ (as NADPH) but not NAD+ can be used in synthesis of fats from carbs
In liver excess glucose is broken down by PPP producing excess NADPH which converts Acetyl coA into FA chains
(glucose is preferentially stored as glycogen until liver and muscle cells are saturated; excess glucose converted to fat stored in fat cells)

64
Q

What are the differences between Pentose Phosphate pathway and the Krebs cycle?

A

?

65
Q

Chemiosmotic mechanism in mitochondria

A

e- pass through chain, releasing lots of energy–>energy used to pump H ions from inner matrix into outer chamber between inner and outer membranes–>high conc of H+ in chamber–>strong neg potential in inner matrix–>H+ flow from high to low conc->Energy from H+ used by ATPase to convert ADP to ATP–>For every 2 e- through ETC, 3 ATP made–>2 H+ pairs from krebs cycle enter ETC later and provide energy for 2ATP per pair–>

66
Q

Know enzymes secretion and functions!!

A

Study!

67
Q

What is the driving force for oxidative phosphorylation?

A

Hydrogen ions in inter-membrane space creates concentration gradient that drives the formation of ATP

68
Q

Energy physics of ATP and ADP

A

ATP–>ADP+Pi=-7300 under lab conditions? but -12000 in real conditions of the body?

69
Q

Know how parietal cells and chief cells operate and the pumps they have in their cell membranes
Chief cells:

A

Chief cells secrete pepsinogen, a proteolytic enzyme and is active at pH 1.8-3.5; its release is stimulated by Ach from vagus nerve or gastric enteric nervous plexus and responds to acid in stomach; chief cells also secrete intrinsic factor

70
Q

Know how parietal cells and chief cells operate and the pumps they have in their cell membranes
Parietal cells

A

Parietal cells produce HCl
Dissociation of water inside cell into H+ and OH-
H ion is pumped out of cell in exchange for K+
K+ leaks outside the cell but is transported back in via H+-K+ ATPase pump
Na+ is reabsorbed into cell due to Na+-K+ basolateral pump
OH- +CO2–>HCO3- which is exchanged for Cl- ions
Cl- ions are secreted through chloride channels into canaliculi

Physiology II Exam II (3 decks)

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