Nervous Control, The Sensory System (physiology)

Question 1

What does the afferent division of PNS consits of?

Answer 1

-Receptors
- Sensory neurons
-Sensory pathways

Question 2

What does the efferent division of the PNS consist of?

Answer 2

• Nuclei
• Motor tracts
• Motor neurons

Question 3

Four types of sensations?

Answer 3

-Superficial sensation
-Deep sensation
-Visceral sensation
-The special senses

Question 4

What are sensory receptors and how do they function?

Answer 4

These are specialized cells that monitor specific conditions.
When stimulated, the transmit information to the CNS in the form of an action potential that travels in the axons of sensory neurons.

Question 5

What role do sensory pathways act and how?

Answer 5

They deliver somatic and visceral information to their final destinations in the CNS using the nuclei, tracts and nerves.

Question 6

What are sensory modalities, give 4.

Answer 6

Unique type of sensation
Pain, touch, vision or hearing.

Question 7

Two divisions of the sensory modalities

Answer 7

General senses
Special senses

Question 8

What are examples of the general senses?

Answer 8

Temperature
Pressure
Touch
Proprioception
Vibration
Pain

Question 9

What are the examples of special senses?

Answer 9

Olfactory
Vision
Gustation
Hearing
Balance

Question 10

What do we mean when we say receptors are transducers ?

Answer 10

They convert various forms of energy into action potentials.

Question 11

What are the differences btwn the three sensory neurons?

Answer 11

Simple receptors- Have free nerve endings.
Complex neural receptors- have nerve endings enclosed in a connective tissue capsule.
Special senses receptors- have specialized receptor cells and they usually release neurotransmitters onto sensory neurons initiating an action potential.

Question 12

What are the four types of sensory receptors?

Answer 12

Exteroceptors
Proprioceptors
Interoceptors
Telecasters

Question 13

Four general sensory receptors

Answer 13

Nociceptors
Thermoreceptors
Mechanoreceptors
Chemoreceptors

Question 14

Where are the pain receptors located?

Answer 14

Superficial portion of the skin.
Around the walls of blood vessels
In the periostea of bone
In joint capsules

Question 15

Where are thermoreceptors found?

Answer 15

The dermis
The hypothalamus
Skeletal muscles
The liver

Question 16

Three classes of mechanireceptors

Answer 16

Tactile receptors
Baroreceptors
Proprioceptors

Question 17

Where are chemoreceptors located

Answer 17

Carotid and aortic bodies

Question 18

What do we call the form of energy in which a receptor is most responsive?

Answer 18

Adequate stimulus

Question 19

What function do the somatic sensory pathways do?

Answer 19

They carry information from the skin and musculature of the body wall, head, limbs and neck.

Question 20

Three major somatic sensory pathways

Answer 20

The dorsal column pathway
The spinothalamic pathway
The spinocerebellar pathway

Question 21

Which types of sensations does the dorsal column pathway carry?

Answer 21

Carry sensation of highly localized touch, vibration and proprioception.

Question 22

What are the spinal tracts involved in the dorsal column pathway and which axons do they link up with?

Answer 22

Fasciculus gracilis- axons from sensory neurons coming from the lower limb and inferior trunk.
Fasciculus cuneatus- axons from the sensory neurons coming from the upper limb, superior trunk and neck.

Question 23

Clinical features of sensory deficits?(4)

Answer 23

Lose your vibration sensibility.
Decrease in position sense.
Loss of ability to identify object by touching them.
Loss of ability to identify letters and numbers placed on your skin.

Question 24

Senses that are provided by the spinothalamic system

Answer 24

Pain and temperature

Question 25

Explain the spinothalamic pathway.

Answer 25

First order neuron- enters the spinal cord
Second order neuron- crosses to the opp side of spinal cord to the spinothalamic tracts and ascend to the thalamus.
The neuron carrying senses of pain and temperature passes through the lateral tracts.
The neuron carrying senses of touch and pressure passes through the anterior tracts.
Third order neuron- takes sensations to the cortex.

Question 26

Clinical features in the lesions of the spinothalamic pathway (3)

Answer 26

Decrease in pain sensibility.
Increase in pain sensibility.
Decrease in temperature sensibility.

Question 27

Where exactly in the cortex are the sensations sent?

Answer 27

The postcentral gyrus

Question 28

What do we call the orderly arrangementof cells and fibers in the tracts and nuclei of the dorsal column system?

Answer 28

Topographic organization

Question 29

What do we call the orderly arrangementof cells and fibers in the tracts and nuclei of the somatosensory system?

Answer 29

Somatotopic organization

Question 30

Which indormation is carried by the spinocerebellar system and to where?

Answer 30

Carry proprioceptive information from the golgi tendon organs and muscle spindles to the cerebellum.