Exam 1: Sensory

Question 1

List the 5 sensory receptors

Answer 1

5 sensory receptors:

Mechanoreceptors

Thermoreceptors

Nociceptors

Electromagnetic receptors

Chemoreceptors

Question 2

Function of Mechanoreceptors?

Answer 2

Function of Mechanoreceptors:

Detect mechanical compression or stretching of the receptor or of tissues adjacent to the receptor

Question 3

Function of Thermoreceptors?

Answer 3

Function of Thermoreceptors:

Detect changes in temperature

*just cold and warm, not specific temperatures

Question 4

Function of Nociceptors?

Answer 4

Function of Nociceptors:

Detect damage occurring in the tissues

Question 5

Function of Electromagnetic receptors?

Answer 5

Electromagnetic receptors:

Detect light on the retina of the eye

Question 6

Function of Chemoreceptors?

Answer 6

Function of Chemoreceptors:

Detect taste in the mouth, smell in the nose, oxygen level in the blood, osmolality of the body fluids, and carbon dioxide concentrations

Question 7

Modality of senation refers to

Answer 7

Sight, touch, hearing, taste, and smell

Question 8

Labeled Line Principle:

_____ of nerve fibers for transmitting _____ _____ modality of sensation

Each receptor type is _____ specific to one _____ of stimulus

_____ _____ to other types of sensory stimuli

Different modalities of sensation depend on the _____ _____ in the CNS when a nerve fiber is stimulated (e.g. pain, touch, sight, sound)

Answer 8

Labeled Line Principle:

Specificity** of nerve fibers for transmitting **only one modality of sensation

Each receptor type is highly specific to one type of stimulus

Non-responsive to other types of sensory stimuli

Different modalities of sensation depend on the termination point in the CNS when a nerve fiber is stimulated (e.g. pain, touch, sight, sound)

Question 9

What are the Mechanisms of Receptor Potential?

Answer 9

Mechanisms of Receptor Potential:

Mechanical deformation

Application of a chemical to the membrane

Change of temperature of the membrane

Electromagnatic radiation

Question 10

receptor potentials:

When receptor potentials rise above _____ in the nerve fiber attached to the receptor, then _____ _____ occur

The more the receptor potential rises above _____ level, the greater the action potential _____

Answer 10

receptor potentials:

When receptor potentials rise above threshold in the nerve fiber attached to the receptor, then action potentials occur

The more the receptor potential rises above threshold level, the greater the action potential frequency

*AP are not graded! Onlytheirfrequency changes!

Question 11

Adaptation of Receptors:

Adapt partially or completely to a _____ stimulus over _____.

Rapid adaptation and _____ adaptation

Answer 11

Adaptation of Receptors:

Adapt partially or completely to a constant stimulus over time.

(Some sensory receptors adapt to a greater extent than others)

Rapid adaptation and slow adaptation

*Note on image there is a large initial response where it starts lowering right away.

Question 12

Slow Adapting Fibers versus Fast Adapting Fibers:

Slow Adapting Receptors: detect _____ stimulus strength

Tonic receptors – transmit for many hours

Rapidly Adapting Receptors: detect _____ stimulus strength

Movement receptors

Answer 12

Slow Adapting Fibers versus Fast Adapting Fibers:

Slow Adapting Receptors: detect CONTINUOUS stimulus strength

Tonic receptors – transmit for many hours

Rapidly Adapting Receptors: detect CHANGE IN stimulus strength

Movement receptors

Question 13

Spatial versus Temporal Summation:

Be able to recognize and understand the concepts

Answer 13

Spatial versus Temporal Summation:

Be able to recognize and understand the concepts

Question 14

Which figure best represents the response of the most rapidly adapting receptor to the stimulus?

Answer 14

Which figure best represents the response of the most rapidly adapting receptor to the stimulus?

B

Question 15

Which figure best represents the response of the most slowly adapting receptor to the stimulus?

Answer 15

Which figure best represents the response of the most slowly adapting receptor to the stimulus?

B

*Always keeps you aware of the stimulus

Question 16

Which of the following statements best describes the receptor potential?

A. The receptor potential is always constant

B. The greater the intensity of the stimulus, the greater the change in receptor potential

C. Any change in the receptor potential will induce an action potential

D. Receptor excitation always involves depolarization of the receptor

Answer 16

Which of the following statements best describes the receptor potential?

B.

The greater the intensity of the stimulus, the greater the change in receptor potential

Question 17

Which of the following statements concerning the mechanoreceptive potential are true?

A. An increase in stimulus energy results in an increase in receptor potential

B. When receptor potential rises above a certain threshold, action potentials will appear in the neuron attached to the receptor

C. The number of action potentials generated in the neuron attached to the receptor is proportional to the receptor potential

D. All of the above

Answer 17

Which of the following statements concerning the mechanoreceptive potential are true?

D.

All of the above

Question 18

Which of the following is a characteristic of almost all sensory receptors?

A. The ability to perceive a mechanical force

B. The ability to be modulated by a change in temperature

C. The ability to be excited by the application of a chemical irritant

D. The ability to adapt to the stimulus

Answer 18

Which of the following is a characteristic of almost all sensory receptors?

D.

The ability to adapt to the stimulus

Question 19

Name 3 Somatic senses:

Answer 19

Somatic senses:

Mechanoreceptive Somatic Sense

Thermoreceptive Sense

Pain Sense

Question 20

Mechanoreceptive Somatic Sense:

_____ and _____ sensation stimulated by mechanical displacement of the tissue

Touch, pressure, vibration, “_____” senses, and _____ position and rate of movement

Answer 20

Mechanoreceptive Somatic Sense:

Tactile and position sensation stimulated by mechanical displacement of the tissue

Touch, pressure, vibration, “tickle” senses, and static position and rate of movement

Question 21

Thermoreceptive Sense:

Detect _____ and _____

Answer 21

Thermoreceptive Sense:

Detect heat and cold

Question 22

Pain Sense:

Activated by _____ _____ _____

Answer 22

Pain Sense:

Activated by damage to tissues

Question 23

Tactile Receptors:

Understand the difference in the tactile receptors

*6 types we will need to know

(Free nerve endings, Meissner’s corpuscle, Expanded tip receptor, Tactile hair, Ruffini’s endings, Pacinian corpuscle)

Answer 23

Tactile Receptors:

Understand the difference in the tactile receptors

*6 types we will need to know

(Free nerve endings, Meissner’s corpuscle, Expanded tip receptor, Tactile hair, Ruffini’s endings, Pacinian corpuscle)

Question 24

Free nerve endings

Answer 24

Free nerve endings:

found in skin and tissues

detect touch and pressure

Question 25

Meissner’s corpuscle

Answer 25

**_Meissner’s corpuscle_:** **touch** receptor **fingertips** **lips** **hairy** skin discern **spatial locations** of touch

Question 26

Expanded tip receptor

Answer 26

**_Expanded tip receptor_:** **fingertips** responsible for **steady-state** signals

Question 27

Tactile hair

Answer 27

**_Tactile hair_:** detect **slight movement** of **any hair** **assists** in **detecting movement** on **surface** of body

Question 28

Ruffini’s endings

Answer 28

**_Ruffini’s endings_:** **deep layers** of the skin **deep internal** tissues **joint capsules** (helps detect joint angulation) signal **_continuous_ states** of **deformation**

Question 29

Pacinian corpuscle

Answer 29

**_Pacinian corpuscle_:** **beneath** the **skin** **deep fascial** tissues **detect tissue _vibration**_ or _**rapid_ changes** in tissue

Question 30

_**Sensory Pathways** for **Transmitting Somatic Signals** into the_ **_CNS_:** All **sensory info enters** the spinal cord **through the** _____ roots of the spinal nerves **then follow one** of **two pathways**: What are the two pathways?

Answer 30

**_Sensory Pathways for Transmitting Somatic Signals into the CNS:_** All **sensory info enters** the spinal cord **through the dorsal** roots of the spinal nerves **then follow** **one** of **two pathways**: **Dorsal column-medial lemniscal system** or **Anterolateral system**

Question 31

**_Dorsal column-medial lemniscal system_****:** **Composed of** _____ myelinated nerve fibers **Transmit signals** to the **brain at** velocities of ___ - ___ **m/sec** \_\_\_\_\_ _____ of **spatial orientation**

Answer 31

**_Dorsal column-medial lemniscal system:_** Composed of **large** myelinated nerve fibers Transmit **signals** to the brain at **velocities of 30-110 m/sec** **High degree** of **spatial orientation** **\***example is **pain**, when the _signal needs to reach your brain immediately_

Question 32

**_Anterolateral system_****:** **Composed of** _____ myelinated nerve fibers **Transmit signals** to the **brain at** velocities of ___ - ___ **m/sec** \_\_\_\_\_ _____ of **spatial orientation**

Answer 32

**_Anterolateral system:_** Composed of **smaller** myelinated nerve fibers Transmit **signals** to the brain at **velocities of 2-40 m/sec** **Lower degree** of **spatial orientation** \*Example is if your hand remains in the fire, your brain needs a _constant reminder_!

Question 33

**_Dorsal column-medial lemniscal system_****:** has _____ myelinated fibers, a _____ velocity, and a _____ degree of spatial orientation vs **_Anterolateral system_****:** which has _____ myelinated fibers, a _____ velocity, and a _____ degree of spatial orientation

Answer 33

**_Dorsal column-medial lemniscal system_:** has **large myelinated** fibers, a **faster velocity**, and a **high degree** of **spatial** orientation vs **_Anterolateral system_:** which has **smaller myelinated** fibers, a **slower velocity**, and a **lower degree** of **spatial** orientation

Question 34

**_Dorsal column-medial lemniscal system_****:** Touch sensations requiring a _____ **degree of localization** of the stimulus Touch sensations requiring transmission of _____ **gradation**s of intensity **Phasic sensations**, such _____ sensations Sensations that signal _____ against the skin \_\_\_\_\_ sensations from the joints

Answer 34

**_Dorsal column-medial lemniscal system:_** Touch sensations requiring a **_high degree**_ of _**localization_ of the stimulus** Touch sensations requiring transmission of **_fine gradations_** of **intensity** **Phasic sensations**, such **vibratory** (change in intensity) **sensations** Sensations that signal **movement against** the **skin** **Position** sensations **from** the **joints**

Question 35

**_Anterolateral system_****:** **Pain** **Thermal sensations**, _____ and \_\_\_\_\_ \_\_\_\_\_ **touch** and **pressure** sensations **Tickle** and _____ sensations S\_\_\_\_ sensations

Answer 35

**_Anterolateral system:_** Pain Thermal sensations, **warmth** and **cold** **_Crude_** (**_non-specific_**) **touch** and **pressure** sensations **Tickle** and **itch** sensations **Sexual** sensations

Question 36

Be aware of the basic locations where different **body areas** are **represented in** the **somatosensory** area

Answer 36

Be aware of the basic locations where different **body areas** are **represented** in the **somatosensory** area

Question 37

Be aware of the basic differences of the **somatosensory area size** in realtion to the **receptor quantity**

Answer 37

Be aware of the basic differences of the **somatosensory area size** in realtion to the **receptor quantity**

Question 38

**2 point discrimination**

Answer 38

**_2 point discrimination_:** the length required to activate 2 receptors with stimuli

Question 39

**Lateral Inhibition**

Answer 39

**_Lateral Inhibition_:** One receptors axons branches into 2 synapses 1) **Normal excitatory** synapse → **_excitation_** 2) an **2nd excitatory synapse** releases a **different neurotransmitter** that **_inhibits other nearby synapses_** (preventing their excitation from the initial stimuli) \*\*\*allows **spacial orientation** of stimuli\*\*\*

Question 40

**_Tactile Receptors_:** **All** involved in **detection of** \_\_\_\_\_ **Different** receptors **detect** different _____ of \_\_\_\_\_ **Pacinian corpuscles** detect **?** **Meissner’s corpuscles** detect **?** \_\_\_\_\_ **signals** transmitted **only in** the **dorsal column pathway**

Answer 40

**_Tactile Receptors_:** All involved in **detection** of **vibration** Different receptors detect **different frequencies** of **vibration** **Pacinian corpuscles** detect **high-frequency** vibrations**\*** from 30 to 800 cycles per second **Meissner’s corpuscles** detect **low-frequency** vibrations**\*** from 2 up to 80 cycles per second **_Vibration signals_ transmitted _only_** in the **_dorsal column pathway_** **\***All detect vibration, but the **frequency activates** the specific receptors

Question 41

**_Proprioception senses include_:** Part of **which pathway**? **Static** _____ senses (\_\_\_\_\_ adapting) \_\_\_\_\_ of _____ senses (**dynamic** proprioception; _____ adapting)

Answer 41

**_Proprioception senses include_:** **Dorsal column-medial lemniscus pathway** **Static position** senses (**slow** adapting) **Rate** of **movement** senses (**dynamic** proprioception; **rapid** adapting)

Question 42

**_Mechanosensitive proprioceptors_:** Part of **which pathway**? Muscle **spindles** (muscle _____ receptors) **Golgi tendon** organs (measure muscle\_\_\_\_\_) **Ruffini**, **Golgi**, **Pacini**, **Free** nerve **endings** (\_\_\_\_\_)

Answer 42

**_Mechanosensitive proprioceptors_:** **Dorsal column-medial lemniscus pathway** Muscle spindles (**muscle stretch** receptors)**\*** Golgi tendon organs (measure **muscle tension**)**\*** Ruffini, Golgi, Pacini, Free nerve endings (**joint**)**\*\*** **\*Golgi and spindles static** as long as strecth or tension is present; **slow** adapting **\*\***Found in specific **joints**; **rapid** adapting; **for rate** of **movement**

Question 43

_Understand **somatosensory projections**, **tracts**, and **receptors** for the_: **Dorsal column-medial lemniscus pathway** (\_\_\_\_\_ceptors or \_\_\_\_\_ceptors) and the **Anterolateral pathway** (\_\_\_\_\_ceptors or \_\_\_\_\_ceptors)

Answer 43

_Understand **somatosensory projections**, **tracts**, and **receptors** for the_: **Dorsal column-medial lemniscus pathway** (Proprioceptors or mechanoreceptors) and the **Anterolateral pathway** (Nociceptors or thermoreceptors)

Question 44

**_Thermoreceptors_:** Receptors located in _____ \_\_\_\_\_ Receptors specific to ? \_\_\_\_\_ receptors begin firing above ? \_\_\_\_\_ receptors begin firing below ?

Answer 44

**_Thermoreceptors_:** Receptors **located in the skin** Receptors **specific** to **either** **_hot_** or **_cold_** **Warm** receptors begin firing **above 30 degrees Celsius** (86 F) **Cold** receptors begin firing **below 24 degrees Celsius** (75.2 f)

Question 45

**_Tickle and Itch Detection_:** Part of which pathway? \_\_\_\_\_ nerve ______ **found in** the _____ \_\_\_\_\_ of the **skin**

Answer 45

**_Tickle and Itch Detection_:** **Anterolateral pathway** **Free nerve endings** found in the **superficial layers** **of** the **skin**

Question 46

**_Pain_:** Part of which pathway? **_Fast pain_:** is felt within _____ after a pain stimulus is applied and can be described as \_\_\_\_\_, \_\_\_\_\_, \_\_\_\_\_, _____ pain **_vs_.** **_Slow pain_:** felt _____ and then increases _____ over time and is associated with _____ \_\_\_\_\_. Can be described as _____ \_\_\_\_\_, \_\_\_\_\_, \_\_\_\_\_, _____ pain and _____ pain

Answer 46

**_Pain_:** **Anterolateral pathway** **_Fast pain_:** is **felt within 0.1 second** after a pain stimulus is applied **Sharp**, **pricking**, **acute**, **electric pain** **_vs_****.** **_Slow pain_:** felt **after 1 second or more** and then **increases slowly over time** and is **_associated with tissue destruction._** Can be described **as slow slow burning**, **aching**, **throbbing**, **nauseous** pain and **chronic** pain

Question 47

**_Nociceptors_ (pain receptors):** Part of **which pathway**? \_\_\_\_\_ nerve endings **Widespread in** the _____ layers of the skin **Widespread in** _____ tissues \_\_\_\_\_ tissues are sparsely supplied \_\_\_\_\_ adapting

Answer 47

**_Nociceptor_ (pain receptors):** **Anterolateral pathway** **Free** nerve endings **Widespread** in the **superficial layers** of the skin **Widespread** in **internal tissues** **Deep tissues** are **sparsely** supplied **_Non_****-adapting!** As long as there is stimulus they will let you know there is pain!

Question 48

**_Stimulus of Nociceptor (pain receptors)_:** Name 3 ways Nociceptors are stimulated

Answer 48

**_Stimulus of Nociceptor (pain receptors)_:** Mechanical, Thermal, Chemical **Mechanical** and **Thermal** are more specific\* to **_fast_** **pain** **Chemical** is more specific\* to **_slow_ pain** \*(all 3 can can be either)

Question 49

**_Fast_ _pain_:** _(\*know fiber, velocity, and NT!\*)_ Signals are **transmitted** by **fast** fibers (\_\_\_\_\_ fibers) **Velocity between** ___ and ___ m/sec Enter the _____ **tract** Can be _____ when _____ receptors and _____ receptors are simultaneously stimulated \_\_\_\_\_ as **main NT**

Answer 49

**_Fast pain_:** _(\*know fiber, velocity, and NT!\*)_ Signals are transmitted by **fast** fibers (**_Aδ fibers_**) Velocity between _**6** and_ **_30_ m/sec** Enter the **_neospinothalamic_** tract Can be **_localized**_ when _**pain_ receptors** and **_tactile_ receptors** are **_simultaneously_** stimulated **_Glutamate_** as **main NT**

Question 50

**_Slow-chronic pain_:** (\*know fiber, velocity, and NT!\*) Signals are **transmitted** by **\_\_\_\_\_ _____ fibers** **Velocity between** ___ and ___ m/sec Enter the _____ **pathway** \_\_\_\_\_ localization Neurotransmiters; _____ as **main NT**

Answer 50

**_Slow-chronic pain_:** _(\*know fiber, velocity, and NT!\*)_ Signals are transmitted by **_type C fibers_** Velocity between _**0.5** and 2_ **m/sec** Enter the **_paleospinothalamic_** pathway **Poor** localization Glutamate and Substance P; **_Substance P_** as **main NT**

Question 51

**_Fast pain vs. Slow pain key points_:** **_Fast pain_** uses _____ fibers, has a _____ velocity (\_\_\_-\_\_\_ m/sec), enters the _____ tract, _____ \_\_\_\_\_ localized, and uses _____ as the main neurotransmitter. **_vs_.** **_Slow pain_** uses _____ fibers, has a _____ velocity (\_\_\_-\_\_\_ m/sec), enters the _____ pathway, _____ \_\_\_\_\_ localized, and uses _____ as the main neurotransmitter.

Answer 51

**_Fast pain vs. Slow pain key points_:** **_Fast pain_** uses **fast Aδ** fibers, has a **faster** velocity (**6**-**30** m/sec), enters the **neospinothalamic** tract, **can be localized**, and uses **glutamate** as the main neurotransmitter. **_vs_.** **_Slow pain_** uses **type C** fibers, has a **slower** velocity (**0.5**-**2** m/sec), enters the **paleospinothalamic** pathway, is **poorly localized**, and uses **Substance P** as the main neurotransmitter.

Question 52

**_Pain_:** **_Double pain sensation_****:** First a fast-\_\_\_\_\_ pain followed by a slow pain \*\*\*Think; **What is main NT** for the first fast pain? the second slow pain?\*\*\* **_Referred pain_****:** Usually through \_\_\_\_\_spinothalamic pathway

Answer 52

**_Pain_:** **_Double pain sensation_: First** a **fast-sharp** pain followed by a **slow pain** \*\*\***Glutamate** is the **main NT** for the **first fast pain**! **Substance P** for the **second slow pain**!\*\*\* **_Referred pain_:** Usually through **paleospinothalamic pathway**

Question 53

**_Pain Modification_:** **2** ways to **modify pain?**

Answer 53

**_Pain Modification_:** **1) _Massage or rubbing_**; Massaging and rubbing activates **mechanoreceptors**. **Pain evoked by** the **nociceptors** (A δ and C fibers) can be **reduced** by **simultaneous activity** of the **mechanoreceptors** **2) _endorphins_** **Inhibit nociceptors\*!** **\***(**inhibits** the **pre-synaptic release** of **Sub P**.)

Question 54

**_Clinical Case example_:** ## Footnote An individual was brought into the ED following a motor vehicle collision. This individual is conscious and reports no loss of consciousness during the accident. There is no physical evidence of any head trauma. However, upon examination of this individual, the following sensory deficits are noted: loss of fine touch and vibration sense in both the left arm and leg including the hand and foot, loss of pain and temperature sense in the right arm and leg including the hand and foot.

Answer 54

**_Clinical Case example:_** Use this case as an example to think about the nerve tracts used, area of the somatosensory cortex used, pain localization principles, main neurotransmitters respoible for the pain recepters, and location of the tactile receptors learned in this lecture.

Question 55

**_The loss of fine touch and vibration sense involves which of the following nerve tracts_?** **A**. Anterolateral system **B**. Dorsal-column system **C**. Corticospinal tract **D**. Medial forebrain bundle

Answer 55

**_The loss of fine touch and vibration sense involves which of the following nerve tracts_?** **B.** Dorsal-column system

Question 56

**_The loss of pain and temperature sense involves which of the following nerve tracts_?** **A**. Corticospinal tract **B**. Pontocerebellar tract **C**. Dorsal-column tract **D**. Anterolateral system

Answer 56

**_The loss of pain and temperature sense involves which of the following nerve tracts_?** **D.** Anterolateral system

Question 57

**_Which of the following areas of the body has the greatest representation in the primary somatosensory cortex_?** **A**. Tongue **B**. Head **C**. Shoulder **D**. Wrist

Answer 57

**_Which of the following areas of the body has the greatest representation in the primary somatosensory cortex_?** **A.** Tongue

Question 58

**_The highest degree of pain localization comes from_?** **A**. Simultaneous stimulation of free nerve endings and tactile fibers **B**. Stimulation of free nerve endings by bradykinin **C**. Nerve fibers traveling via the paleospinothalamic system **D**. Stimulation of the A δ fibers

Answer 58

**_The highest degree of pain localization comes from_?** **A.** Simultaneous stimulation of free nerve endings and tactile fibers \***_localized_** when **pain** receptors and **tactile** receptors are **simultaneously stimulated**; Stimulation of the A δ fibers is what causes the pain and localization signal to travel quickly, but it is not where pain localization "comes from"

Question 59

**_Which substance is responsible for activating pain receptors_?** **A**. Bradykinin **B**. Glutamate **C**. Substance P **D**. Endorphines

Answer 59

**_Which substance is responsible for activating pain receptors_?** **A.** Bradykinin \*B & C are NT! D inhibits the pre-synaptic release of Sub P.

Question 60

**_Second pain is initiated by_?** **A**. C fibers and is a sharp, highly localized sensation **B**. C fibers and is a dull, poorly localized sensation **C**. Aδ fibers and is a sharp, highly localized sensation **D**. Aδ fibers and is a dull, poorly localized sensation

Answer 60

**_Second pain is initiated by_?** **B.** C fibers and is a dull, poorly localized sensation

Question 61

**_Pacinian corpuscles are located_?** **A**. Superficially in the dermis and detect rapid changes **B**. Deep in the dermis and detect rapid changes **C**. Superficially in the dermis and detect slow changes **D**. Deep in the dermis and detect slow changes

Answer 61

**_Pacinian corpuscles are located_?** **B.** Deep in the dermis and detect rapid changes