SF3-physiology Flashcards

(54 cards)

1
Q

Tonic receptors

A

-slow or nonexistent adaptation
-continous signal transmission as long as stimuli is present
-monitoring parameters are continuously raised
Ex. Posture, proprioceptiors

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2
Q

Physic receptors

A

-fast adaptation
-stop transmitting if intensity of stimulus is continous/constant
-allows body to ignore superficial and constant stimuli
Ex. Touch of clothes

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3
Q

On what does conduction velocity depend?

A
  • the axons diameter

- degree of myelination (Salvatore conduction)

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4
Q

What are the two classes of nerve fibers?

A

General (motor+sensory):
-type A= large, myelinated fibers for fast signaling
-type C= small, unmyelinated fibers for slow signaling
Exclusive sensory:
-group 1A= fastest, muscle spindles
-group 1B= a bit slower, golgi tendon organs
-group 2= types A, discriminative touch
-group 3= types A,temperature, deep touch, acute pain
-group 4= type C, burning pain, itching, temperature, deep touch

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5
Q

What is somatovis real sensitivity?

A
In skin and mucus:
-tactile sense (superficial)
-thermoreception
In locomotor system:
-proprioception (deep)
In most organs:
-nociception (pain)
In thoracoabdominal visceral:
-visceral sensitivity
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6
Q

What is the tactile sense?

A
  • The detecting of non-harmful mechanical stimuli
  • processed in CNS
  • touch, pressure, vibration, tickle
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7
Q

What kind of receptors does tactile sense have?

A
  • slowly adapting mechanoreceptors
  • rapidly adapting mechanoreceptors
  • type C mechanoreceptors
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8
Q

What are the types of slowly adapting mechanoreceptors?

A
  • Merkel’s discs

- ruffini’s endings

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9
Q

What are the types of rapidly adapting mechanoreceptors?

A
  • meissner’s corpuscles
  • krause’s corpuscles
  • tactile hair
  • type C fibers (free nerve endings)
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10
Q

What are the very rapidly adapting mechanoreceptor?

A

Pack Ian corpuscles

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11
Q

What is proprioception?

A

The sensory ability to control position and movement sequences
The perception of body in space

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12
Q

Where are the proprioception receptors localized?

A

In locomotor system

Muscles, tendons, bones, joints

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13
Q

What is the classification of proprioception receptors?

A

Muscle receptors:
- muscle spindle
-golgi tendon organ
Joint receptors

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14
Q

What is the muscle spindle?

A
  • fusiform budles of encapsulated and specialized muscle fibers (intrafusal)
  • sensitive to muscle stretching/change of length
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15
Q

What are the two types f intrafusal muscle fibers?

A
  • nuclear bag fibers=central portion dilated with multiple nuclei inside
  • nuclear chain fibers=nuclei arranged in a row
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16
Q

What are the sensory and motor components of muscle spindle?

A
  • primary+secondary sensory nerve fibers spiraling around central portion of intrafusal fibers, inform of muscle stretching
  • gamma motor neurons= a lower motor neuron keeping spindles tight, adjusting sensitivity
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17
Q

What are the muscle spindle sensory components?

A

primary/type 1a sensory fibers:
-wraps central part of both nuclear bag and chain fibers w annulospiral nerve endings
-rapid adaptation, constantly monitoring change in velocity of muscle stretch
Type 2 sensory fibers:
-innervates the ends of nuclear bag and chain fibers
-non adapting, informs about position continuously

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18
Q

What is the golgi tendon organ?

A
  • proprioception receptor organ situated at the origins/insertion of muscles into tendons
  • innervated by single afferent type 1b sensory nerve endings spiraling around collagen strands
  • detects muscle tension, both contraction and extension
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19
Q

What are the types of receptors in proprioception?

A
  • ruffini corpuscles= joint capsule, degree of rotation of joint
  • pacini’s corpuscles= joint capsule, sense of speed of movement
  • golgi tendon organs= ligaments, jerks or sudden contraction of tendon
  • muscle spindles= muscles, length/time of contraction
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20
Q

What are the thermoreceptors?

A

-sense of cold= surface of skin, Krause’s corpuscle, free endings w myelin
-sense of heat= deeper layers, ruffini’s corpuscles, free unmyelinated endings
Rapid adaptation

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21
Q

What are the characteristics of nociceptors?

A
  • free nerve endings
  • non existing in CNS, most of viscera
  • very little/no adaptation
  • continue perceiving stimuli until it ends
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22
Q

What are the two types of pain?

A
Fast/acute pain:
-mainly felt in superficial tissues
-not felt in deeper tissues
Slow/chronic pain:
-associated w tissue destruction
-can occur in almost all types of tissues
23
Q

What are the types of nociceptors?

A

Polymodal:
-responds to mechanical, thermal, chemical high intensity stimuli
-slow, type C or 4 fibers
Mechanosensitive:
-fast pain, mechanical height intensity stimuli
-fibers A-delta or 3
-

24
Q

What are the types of pain stimuli?

A
  • Thermal pain= below 10, above 48 degrees
  • chemical pain= bradykinin, histamine, serotonin, Ach, acids, K+
  • mechanical pain= tissue disruption, ischemia, muscle spasm, excessive pressure
25
What is the analgesia system?
In CNS, controlsystem suppressing pain impulses - areas in mesencephalon, upper pons, 3rd&4th ventricle - areas of lower pons, upper&lateral medulla - pain inhibitory complex in dorsal horns of spinal cord
26
What are the characteristics of visceral pain?
- mostly unconscious, related to regulation of activity - most consciously perceived sensations in response to mechanical/chemical stimuli - type 4 fibers
27
Most common causes of visceral pain?
- tissue ischemia - chemical stimuli - smooth muscle spasm - inflammation
28
What is referred pain?
- sensation of pain in part of body not related to tissue causing pain - convergence theory
29
Characteristics of conscious ascending tracts
3 neurons - 1 neuron= sensory receptor of spinal nerve synapses in posterior root ganglion - 2 neuron= decussates and travel up spinal cord - 3 neuron= synapses in sensory nucleus in thalamus, projects to sensitive cerebral cortex
30
Lateral and anterior spinothalamic tracts
Lateral= pain and temperature Anterior= crude touch, pressure -1 neuron= enters dorsal root ganglia and synapses in posterior horns -2 neuron= decussates and runs up through medial leminiscus of brain stem -3 neuron= synapses in thalamus, through ventral posterolateral nucleus to sensory cortex
31
Leminiscal/dorsal column tract
Fine touch, vibration, awareness of muscle coordination F. Gracilis= lumbosacral level F. Cuneatus= cervical level -1 neuron= enters dorsal root ganglia -2 neuron= synapses in medulla, decussates and travels up medial lemniscus of brain stem -3 neuron= synapses in ventral posterolateral nucleus of thalamus, ends sensory cortex
32
Characteristics of unconscious spinocerebellar tract
2 neurons, unconscious proprioception of extremities and trunk (golgi tendon organ, muscle spindle) Posterior/dorsal= direct, lower extremities Anterior/ventral= crossed, trunk/upper extremities -1 neuron= enters via dorsal root ganglia, synapses in dark column of dorsal nucleus -2 neuron= synapses, decussates (anterior)or not (posterior) ascends to medulla and/or pons, through cerebellum peduncles and ends at cerebellar cortex
33
Characteristics of motor neurons
- alpha motorneurons innervate extrafusal skeletal muscle fibers - gamma motorneurons innervate intrafusal skeletal muscle fibers, makes up muscle spindle
34
Characteristics of conscious descending pathways
3 neurons - 1 neuron= upper motor neuron, motor area of cerebral cortex, decussates and descends down to anterior horns of spinal cord - 2 neuron= very short, synapses in anterior horn - 3 neuron= lower motor neuron, exits through anterior root to skeletal muscle
35
What is the pyramidal system?
- Conscious - Upper Motor neurons responsible for activating skeletal muscles for fine, voluntary and learnt movements - corticospinal tracts (lateral/ventral)
36
What is the extrapyramidal system?
- unconscious - upper motor neurons responsible for antigravity, involuntary and subconscious movements - for the assistance, modulation and regulation of pyramidal system - reticulospinal/vestibulospinal/rubrospinal/tactospinal/olivospinal tracts
37
Characteristics of pyramidal system?
``` Pass through: -internal capsule -cerebral peduncle -basal part of pons -pyramids of medulla 3 neurons= UMN+Interneuron=LMN ```
38
Lateral and anterior corticospinal tract
Fine movements, voluntary, learnt and conscious - 1 neuron= UMN in ventral cortical layer of corona radiata, go to pyramids in medulla. Lateral decussates, anterior is ipsilateral - 2 neuron=Interneuron, short, synapses in anterior horn of f spinal cord - 3 neuron= LMN, synapses still in anterior horn, goes to skeletal muscle
39
What is the corticonuclear tract?
- Originating in face, primary motor cortex - does not reach spinal cord - involves the cranial nerves - most fibers end in reticular nuclei - most receive bilateral corticonuclear fibers
40
Characteristics of extrapyramidal system?
- involuntary motor tracts alternative to pyramidal tracts - originates in brainstem, does not pass the medullary pyramids - responsible for involuntary, subconscious and antigravity movement - maintains balance/equilibrium, posture while voluntary movements are performed
41
Rubrospinal tract
Facilitates flexor activity, inhibits antigravity and flexor muscles - 1 neuron= UMN in red nucleus of cerebral cortex & cerebellum, decussates and go through pons and medulla to lateral white matter - 2 neuron= Interneuron, synapses in grey horns - 3 neuron= LMN, from grey horns to skeletal muscle
42
Vestibulospinal tract
Facilitates extension, inhibits flexion, postural balance - 1 neuron= UMN, lateral vestibular nucleus of pons and medulla, receives into from vestibular Nerve and cerebellum, ipsilateral - 2 neuron= Interneuron, synapses in grey horns - 3 neuron= LMN, from grey horns to skeletal muscle
43
Reticulospinal tract
Controls proximal and axial muscles, extensor responses (position) - 1 neuron= UMN, reticular formation in midbrain, pons (mainly ipsilateral, pontine reticulospinal tract/medial to anterior white matter) medulla (crossed and direct, medullary reticulospinal tract/lateral to lateral white matter), receives info from cerebral cortex, thalamus, cerebellum. - 2 neuron= Interneuron, short, synapses in grey horns - 3 neuron= LMN, from grey horns to skeletal muscle
44
Tectospinal tract
Reflex postural movement of head due to visual/auditory movement - 1 neuron= UMN, from superior culiculus of midbrain, decussates mainly, to anterior white matter - 2 neuron= Interneuron, short, in grey horns - 3 neuron= LMN, from grey horns to skeletal muscle
45
Olivospinal tract
Not known function - 1 neuron= UMN, inferior Olivary nucleus of medulla, mainly decussates, go to lateral white matter - 2 neuron= Interneuron, short, synapses in grey horns - 3 neuron= LMN, from grey horns to skeletal muscle
46
External Chemoreceptors and their basic function
Sensory receptors responding to chemical changes - alimentary - defencive - sexual - communicator
47
The taste bud
2 types of modified epithelium - taste cells -basal cells (stem cells) Taste pores is the only communication btw tastecells and exterior
48
Categories of taste
- sweet= organic molecules, sucrose, aldehyde - bitter= alkaloids, Quinn, caffeine - salty= ions of ionizable salts, NaCl, KCl - umami= amino acids, glutamate
49
Channels for taste
Ion channels= salty, sour, bitter | Metabotrophic/G-protein= bitter, sweet
50
Taste transduction
- chemical stimuli - membrane potential - neurotransmission - AP through sensory neuron - impulse to CNS
51
Gustatory pathway
- 1 neuron= CN 7, 9, 10 sends signals to brainstem - 2 neuron= synapses in gustatory nucleus of tractus solitarius in medulla - 3 neuron= synapses in thalamus, ends in gustatory cortex
52
Structures of olfactory sensitivity
- Main Olfactory epithelium/MOE - Main Olfactory bulb/MOB - Vomeronasal organVNO - Acessory olfactory bulb/AOB
53
Transduction pathway of olfactory sensitivity
- chemical signal in olfactory epithelium - electric signal to OB - electrical signalto brain - olfactory tract
54
What are the three cell types of olfactory epithelium?
- supporting cells - olfactory cells - basal cells