Ch.2, Nervous System Cont.

Question 1

Why does info enter the posterior root of the dermatome?

Answer 1

Bc posterior root is sensation; it is afferent and transmits to spinal cord

Question 2

Posterior root ganglion

Answer 2

The spinal ganglion contains the cell bodies of sensory neurons situated in the posterior root of each spinal nerve (except for spinal nerve C1). These neurons are known as first-order neurons of the somatosensory system and carry sensations related to touch, vibration, proprioception, pain and temperature.

Question 3

Matter organization in dermatomes

Answer 3

White matter outside; grey matter inside = opposite of the cerebrum

Question 4

Difference between white matter and grey matter; difference in function

Answer 4

Grey matter consists of neuronal l cell bodies and their dendrites. The dendrites are short protrusions (like little fingers) that communicate with neurons close by. In contrast, your white matter consists of the long axons of neurons that transmit impulses to more distant regions of your brain and spinal cord.
GREY MATTER FUNCTIONS: Because grey matter has a large number of neuronal bodies (which contain the nucleus of the cell), this is where information processing happens. The grey matter is the seat of a human’s unique ability to think and reason. The grey matter is the place 1 J where the processing of sensation, perception, voluntary movement, learning, speech and cognition takes place.
WHITE MATTER FUNCTION: White matter’s role is to provide communication between different grey matter areas and between grey matter and the rest of your body.

Question 5

How does info leave the dermatome?

Answer 5

Through anterior root (efferent)

Question 6

What does the law of Bell aMnd Magendie not apply to?

Answer 6

does not apply to Vision or hearing

Question 7

Propriosensation

Answer 7

awareness of where body is in space I the

Question 8

What does somatosensation not include?

Answer 8

Not vision, olfaction, taste or auditory

Question 8

PNS vs. ANS with breathing and urination

Answer 8

ANS: relaxes airway to get more air in
PNS: constricts airway bc we don’t need as much air
ANS: contracts base of bladder to restrict urination
PNS: stimulates bladder for urination

Question 9

What are reflexes?

Answer 9

Don’t involve brain only spinal cord, more simple circuits l

Question 9

What does it mean to say that neuronal circuits are the functional units of the nervous system

Answer 9

Functions of the nervous system are carried out by series of neurons connected to one another: neurons don’t work in isolation

Question 10

Sensory and motor divisons pervade the nervous system means

Answer 10

Posterior is typically always sensory, anterior is always motor
Anterior/ventral (spinal cord): efferent
Posterior/dorsal root=afferent

Question 11

Why can we use anterior/ventral and posterior/dorsal as interchangeable in the spinal cord but not brain?

Answer 11

Because spinal cord depends on whether you’re talking about a biped or quadruped (anterior side of the spinal cord would be ventral in dogs)

Question 12

Neocortex, motor input vs output /

Answer 12

Layer IV: receives sensory inputs
Layers V and VI send motor outputs

Question 13

Additions to the CNS; adaptations over time

Answer 13

= some simpler animals only have spinal cords, but over time as animals become more complex = brainstems and forebrains were added. noire complex = more structures

Question 14

Brain systems are organized hierarchy and parallel

Answer 14

multiple hierarchal organized circuits acting in parallel allow the performance of simultaneous behaviors
(Primary – secondary – tertiary)

Question 15

What is the exception to crossed brain circuits?

Answer 15

Olfactory, AND EVERYTHING IN THE AUTONOMIC, SOMATIC, AND ENTERIC NERVOUS SYSTEM: PNS IS NEVER CROSSED

Question 16

What does it mean to say that some brain functions are localized and distributed?

Answer 16

Some brain functions are localized to one specific region: fear is localized to the amygdala

Question 17

How is memory parsed apart and processed in parallel in different regions?

Answer 17

Memory: different memories are processed differently but episodic memory tends to be localized in the hippocampus

Question 18

What does lateralized mean?

Answer 18

Language is usually lateralized to one side; spatial functions are usually lateralized to the right: not every function is bilateral

Question 19

What is the difference between excitation and inhibition?

Answer 19

The brain uses excitation to produce some action and inhibition to prevent others

Question 20

What does the spontaneous rate of activity of neurons mean?

Answer 20

Baseline rate of activity without any excitation or inhibition

Question 21

Why does brain injury typically result in either a loss or release of behavior? Example of Parkinsons

Answer 21

Because the excitation and inhibition balance has been messed up: Parkinson’s can either cause rigidity of muscles (a lack of excitation to get them moving fluidly) or tremors (not enough inhibition to stop muscle shakes)

Question 22

How are object recognition pathways and motor control pathways distinct?

Answer 22

V1 (primary visual cortex) has the ventral stream and dorsal stream
Ventral: CONSCIOUS, controls the what pathway, object recognition DAMAGE = usually damage to the temporal lobes, they cannot recognize what should be familiar objects, in rare cases they can’t even see it
Dorsal: UNCONSCIOUS, where pathway, how to interact with objects, vision for action DAMAGE = can’t reach for objects

Question 23

Explain how a right hand touch would transmit somatosensation to the spinal cord.

Answer 23

right hand would transmit to right spine, somatic is not crossed

Question 24

Dermatome

Answer 24

structures that are posterior = almost always sensory
structure that are anterior= almost always motor

Question 25

What does numbness vs inability to move mean when considering spinal cord damage?

Answer 25

For instance, if a person has numbness in the fingers of the left hand but can still move the hand fairly normally, one or more of the posterior (dorsal) nerves in spinal cord segments C7 and C8 must be damaged. In contrast, if sensation in the hand is normal but the person cannot move the fingers, the anterior (ventral) roots of the same segments must be damaged. Clinical Focus 2-4, Bell Palsy, further explores the loss of motor function.

Question 26

1. Two sets of SNS nerves, the and the , receive sensory information or send motor signals to muscles, or both.

Answer 26

sensory and motor nerves

Question 27

SNS nerves on the left side of the spinal cord control ——function on the side of the body.

Question 28

SUBCORTICAL REGIONS

Answer 28

Subcortical regions make intimate reciprocal connections with cortical areas that process sensory, perceptual, cognitive, and motor functions. When the cortical areas perceive a threat, such as an angry dog, they communicate with subcortical regions that have already begun to increase breathing and heart rate via the sympathetic nervous system. This relation between the cortical and subcortical areas illuminates another principle of CNS organization: redundant and overlapping functions exist at many levels of the nervous system.

Question 29

How does the wrist analogy explain the situation of the midbrain, hindbrain, and diencephalon?

Answer 29

fist: diecephalon
wrist: midbrain
Forearm: hindbrain; longest/thickest part

Question 30

3 main functions of the basal ganglia

Answer 30

1: movement fluidity
2: connecting sensory regions to motor regions
3: associative learning which is needed for motor learning

Question 31

How does the ANS interact with the CNS AND SNS?

Answer 31

through ganglia, act as mini brains to control the organs

Question 32

Difference between polysynaptic and monosynaptic circuits

Answer 32

poly: means there is at least one interneuron between a sensory neuron and a motor neuron (WITHDRAWING HAND FROM HOT OBJECT)
mono: means there is not an interneuron here (THE CIRCUIT RESPONDS FASTER) INCLUDES THINGS LIKE THE PATELLAR REFLEDX