Somatic Sensation

Question 1

Somatic sensation

Answer 1

Enables out body to feel, ache, sense hit or chill, and to know what its parts are doing

Question 2

Two major types of skin

Answer 2

Hairy

Glabrous (hairless)

Question 3

Skins outer layer

Answer 3

Epidermis

Question 4

Skins inner layer

Answer 4

Dermis

Question 5

Mechanoreceptors

Answer 5

Sensitive to physical distortion such as bending or stretching

They are unmylenated axon branches that are sensitive to stretching, bending l, pressure or vibration

Question 6

Receptors that respond quickly at first but then stop firing even though stimulus continues

Answer 6

Rapidly adapting receptors

Meisser and pacinian corpuscles

Question 7

Receptors that generate a more sustained response during a long stimulus

Answer 7

Meek led disks and ruffinis endings

Question 8

___are more receptive to high frequency stimulus

Answer 8

Pacinian corpuscles

Question 9

____are more sensitive to low frequency stimuli

Answer 9

Meissners corpuscles

Question 10

Mechanics of pacinian corpuscles

Answer 10

Capsule of tissue with axon in the middle. When capsule is compressed, energy is transferred to the nerve terminal and it’s membrane is deformed.

Machanisensitive channels open and current flowing through the channels generates a receptor potential, which is depolarizing.

If depolarization is large enough, it will fire an action potential

Question 11

What happens is pressure is maintained

Answer 11

Layers slip past one another and transfer the stimulus energy in such a way that the axon terminal is no longer deformed.

Receptor potential dissipates

Question 12

What happens if pressure is released

Answer 12

Events reverse themselves and the terminal depolarizers again and may fire another action potential

Question 13

Mechosensitive ion channels

Answer 13

Convert mechanical force into a change of ionic current

They are g-protein coupled receptors

Question 14

What part of body had most mechanoreceptors

Answer 14

Fingertip

Question 15

Axons bringing info from the somatic sensory receptors to the spinal chord or brain stem are…

Answer 15

Primary afferent axons

Question 16

Receptive fields of human sensory receptors

Answer 16

Some receptive fields are realistically small and some are large

Question 17

Types of mechanosensitive ion channels

Answer 17

Some are sensitive to stretching of lipid membrane -tension indices ion channel to open

Others open when force is applied to extracellular structures linked to the channels by peptides

Mechanically sensitive channels may also be linked to intracellular proteins, especially those of the cytoskeleton - deformation of the cell and stress on its cytoskeleton generate forces that regulate channel gating

Question 18

Spinal segments

Answer 18

Divided into four groups and each segment is named after the vertebra adjustment to where the nerves originate

Question 19

Anatomy of spinal cord

Answer 19

Has inner core Greg matter with thick covering of white matter.

White matter is called columns.

Grey matter is divided into dorsal horn, intermediate zone, central horn

Question 20

What modifies unconcious reflexes

Answer 20

Axons entering dorsal horn and branch. One branch synapses in the deep part of the dorsal horn on second order sensory neurons

Question 21

Pathway serving touch

Answer 21

Dorsal column medial lemniscal pathway

Question 22

Proprioception consists of two main components

Answer 22

Joint Position Sense

– Kinesthesia

Question 23

Pathway of touch

Answer 23

S1 Cortex

thalamus

Dorsal columns/medulla

Touch receptors

Question 24

What part of the thalamus does touch go to

Answer 24

Ventral posterior nucleus

Question 25

Medial lemniscus

Answer 25

Axons of dorsal column nuclei ascend within this white matter tract

Question 26

Dorsal column nuclei

Answer 26

Axons of dorsal column terminate this. Junction of spinal cord and medulla

Question 27

Proprioception

Answer 27

Awareness of body in space

Question 28

Area 3a

Answer 28

Posterior parietal cortex. It receives dense inputs from VO nucleus of the thalamus It’s neurons are very responsive to somatosensory stimuli Lesions here unpair sensation When electricity stimulates it, it evokes somatic sensory experiences

Question 29

Areas one and two receive input from..

Answer 29

3b Area 3b-1 sends mostly texture info Area 2 emothasizes size and shape

Question 30

Somatotopy

Answer 30

Mapping of body’s surface sensations onto a structure in the brain

Question 31

What determines how much brain area an individual body part takes up

Answer 31

How important it is to the species. Ex-vibrissae are more important in rodants than paws. But fingers and hands are more important to humans

Question 32

Barrels

Answer 32

Whiskers are stamped on the mouse brain. Each barrel is associated with a single whisker

Question 33

Brain plasticity and use of different body parts

Answer 33

Monkeys were trained to use selectedndogits for a good reward. After several weeks of training, microelectrodemmappijg experiments showed that representation of the stimulated digits had expanded in comparison with the adjacent

Question 34

Agnosia

Answer 34

Inability to recognize objects even though simple sensory skills seem to be normal

Question 35

Asterogjosia

Answer 35

Can not recognize common objects by feeling them

Question 36

Neglect syndrome

Answer 36

Part of body of visual field is ignored

Question 37

Sensation

Answer 37

absorbing raw energy (e.g., light waves, sound waves) through our sensory organs

Question 38

Transduction

Answer 38

conversion of this energy to neural signals

Question 39

Attention

Answer 39

: concentration of mental energy to process incoming information

Question 40

Perception

Answer 40

selecting, organizing, and interpreting these signals

Question 41

tereo vision allows us to detect the 3rd dimension of Depth by

Answer 41

VERGENCE

Question 42

Hyperopia

Answer 42

Far sighted

Question 43

Myopia

Answer 43

Nearsighted

Question 44

Nociceptors

Answer 44

Free stanching unmylinated axon . Unmylinated nerve endings sense that the body is being damaged

Question 45

What is the two point discrimination test and how does it work

Answer 45

It determines spatial resolution Bring two points closer together until they feel like one point

Question 46

What is grey matter divided into in spinal chord

Answer 46

dorsal horn, intermediate zone, central horn

Question 47

Dorsal root function

Answer 47

Allow sensory nerve to enter spinal cord