Qs Chapter 14: The Somatic Nervous System Flashcards Preview

A&P > Qs Chapter 14: The Somatic Nervous System > Flashcards

Flashcards in Qs Chapter 14: The Somatic Nervous System Deck (54)
Loading flashcards...
1
Q

What are the special senses?

A

Special senses are associated with specific organs such as the tongue or the eye.

  • Olfaction (smell)
  • Gustation (taste)
  • Audition (hearing)
  • Equilibrium (balance)
  • Vision
2
Q

What is a general sense?

A

Sensory structures that are distributed throughout the body and in the walls of various organs

3
Q

What nervous system are the special senses in?

A

Somatic nervous system because they are consciously perceived through cerebral processes.

Some can contribute to autonomic function.

4
Q

What do the general senses include?

A
Somatosensation (sensations assoicated with the skin and body) 
- touch 
- tactile 
- pressure 
_vibration
- temperature 
- pain 

Also includes visceral senses - separate from somatic nervous system (do not rise the the level of conscious perception)

5
Q

How are sensory cells classified?

A
  • Structural

- Functional

6
Q

What are the structural classifications of sensory cells?

A
  • Based on anatomy of the cell that is interacting with the stimulus (free nerve endings, encapsulated endings, specialized receptor cell)
  • Where cell is located relative to the stimulus (interoceptor, exteroceptor, proprioceptor)
7
Q

What are the functional classifications of sensory cells?

A

How the cell transduces the stimulus to a neural signal

8
Q

What are chemoreceptors the basis for?

A

Olfaction and gustation

They respond to chemical stimuli

9
Q

What are mechanoreceptors the basis for?

A

Somatosensation as well as audition and equilibrium in the inner ear.

Respond to mechanical stimuli

10
Q

What do thermoreceptors detect?

A

Temperature changes

11
Q

What do photoreceptors detect?

A

Sensitive to light energy

12
Q

Spinal input to the brain enters through one of two pathways to reach the ______. What are the pathways?

A
  1. Spinal cord
  2. Brain stem

They are going to the diencephalon.

13
Q

When does the sensory input travel through the spinal cord?

A

For somatosensory input from the body

14
Q

When does sensory input travel through the brainstem?

A

Everything except somatosensory input from the body and visual and olfactory systems.

15
Q

Sensory information in the diencephalon reaches what part of the brain?

A

The thalamus

16
Q

Why is it necessary for sensory systems to go through the thalamus?

A

To reach the cerebral cortex

  • Not the case for olfaction that is directly connected to the frontal and temporal lobes
17
Q

What are the two major tracts in the spinal cord that originates from sensory neurons in the dorsal root ganglia?

A

Dorsal column system

Spinothalamic tract

18
Q

What are the major differences between the dorsal column system and the spinothalamic tract?

A

Type of information that is relayed to the brain and where the tracts decussate

19
Q

What does the dorsal column system primarily carry and where does it go?

A

Information about touch and proprioception and crosses the midline to the medulla?

20
Q

What does the spinothalamic tract carry and where does it go?

A

Information on pain and temperature sensation and crosses the midline in the spinal cord at the level at which it enters

21
Q

What doe the trigeminal nerve add to spinothalamic tract and the dorsal column system?

A

Adds similar sensation information from the head

22
Q

Where does the auditory pathway pass through?

A

Multiple nuclei in the brain stem in which additional information is extracted from the basic frequency stimuli processed by the cochlea.

23
Q

What is sound localization made possible through?

A

The activity of brains stem structures

24
Q

When the vestibular system enters the brain, it influences activity in what parts?

A

Cerebellum, spinal cord, and cerebral cortex.

25
Q

How does the visual pathway segregate information from the two eyes?

A

So that one half of the visual field projects to the other side of the brain

26
Q

What does the ventral visual stream do?

A

Connect structures in the temporal lobe that are important for long-term memory formation.

27
Q

What does the dorsal visual stream interact with and where?

A

The somatosensory cortex in the parietal lobe.

Influences the activity in the frontal lobe to generate movements of the body in relation to visual inforamtion.

28
Q

Where do the motor components of the somatic nervous system begin?

A

The frontal lobe of the brain where the prefrontal cortex is responsible for high functions such as working memory

29
Q

What functions of the prefrontal lobe feed into the secondary motor areas?

A

Integrative and associate functions which help plan movements

30
Q

What initiates movements?

A

The premotor cortex and supplemental motor area feed into the primary motor cortex which initiates movemvents

31
Q

What do Large Betz cells do?

A

Project through the corticobulbar and corticospinal tracts to synapse on lower motor neurons in the brainstem and ventral horn of the spinal cord.

Responsible for generating movements of skeletal muscles

32
Q

What does the extrapyramidal system include?

A

Projections from the brainstem and higher centers that influence movement, mostly to maintain balance and posture, as well as to maintain muscle tone

33
Q

What has tracts that project to the spinal cord in the extrapyramidal system?

A
  • Superior colliculus and red nucleus in the midbrain
  • Vestibular nuclei in the medulla
  • Reticular formation throughout the brainstem
34
Q

Motor pathways project to the spinal cord to synapse with motor neuron in the ______

A

Ventral horn of the spinal cord

35
Q

What do lower motor neurons do?

A

Connect to skeletal muscle and cause contraction

36
Q

What is it called where the neurons connect to the muscles?

A

Neuromuscular junctions.

37
Q

What is a motor unit?

A

One motor neuron connects to multiple muscle fibers within a target muscle.

38
Q

Why do the number of innervated muscle fibers in a motor unit vary?

A

Basis of the precision necessary for that muscle and the amount of force necessary for that motor unit.

39
Q

What are the simplest circuits in the somatic nervous system?

A

Reflexes

40
Q

What does a withdrawal reflex from a painful stimulusrequire?

A

Sensory fiber that enters the spinal cord and the motor neuron that projects to a muscle

41
Q

What can make the connections in a reflex circuit more complex?

A

Antagonist and postural muscles can be coordinated with the withdrawal

42
Q

What is the corneal reflex?

A

Contraction of the orbicularis oculi muscle to blink the eyelid when something touches the surface of the eye

43
Q

How do stretch reflexes maintain a constant length?

A

Causing contraction of a muscle to compensate for a stretch that can be sensed by a specialized receptor called a muscle spindle.

44
Q
What type of receptor cell is responsible for
transducing pain stimuli?
a. mechanoreceptor
b. nociceptor
c. osmoreceptor
d. photoreceptor
A

b. nociceptor

45
Q
Which submodality of taste is sensitive to the pH of
saliva?
a. umami
b. sour
c. bitter
d. sweet
A

b. sour

46
Q
What type of receptor cell is involved in the sensations
of sound and balance?
a. photoreceptor
b. chemoreceptor
c. mechanoreceptor
d. nociceptor
A

c. mechanoreceptor

47
Q
Which nucleus in the medulla is connected to the
inferior colliculus?
a. solitary nucleus
b. vestibular nucleus
c. chief sensory nucleus
d. cochlear nucleus
A

d. cochlear nucleus

48
Q

Which location on the body has the largest region
of somatosensory cortex representing it, according to the
sensory homunculus?
a. lips
b. thigh
c. elbow
d. neck

A

a. lips

49
Q

Which region of the frontal lobe is responsible for
initiating movement by directly connecting to cranial and
spinal motor neurons?
a. prefrontal cortex
b. supplemental motor area
c. premotor cortex
d. primary motor cortex

A

d. primary motor cortex

50
Q

Which region of gray matter in the spinal cord contains
motor neurons that innervate skeletal muscles?
a. ventral horn
b. dorsal horn
c. lateral horn
d. lateral column

A

b. dorsal horn

51
Q

What is the name for the topographical representation
of the sensory input to the somatosensory cortex?
a. homunculus
b. homo sapiens
c. postcentral gyrus
d. primary cortex

A

a. homunculus

52
Q

The sweetener known as stevia can replace glucose
in food. What does the molecular similarity of stevia to
glucose mean for the gustatory sense?

A

The stevia molecule is similar to glucose such that is will bind to the glucose receptor in sweet-sensitive taste buds. However, it is not a substrate for the ATP-generating metabolism within cells

53
Q

Following a motorcycle accident, the victim loses the
ability to move the right leg but has normal control over
the left one, suggesting a hemisection somewhere in the
thoracic region of the spinal cord. What sensory deficits
would be expected in terms of touch versus pain? Explain
your answer.

A

The right leg would feel painful stimuli, but not touch, because the spinothalamic tract decussates at the level of entry, which would be below the injury, whereas the dorsal column system does not decussate until reaching the brainstem, which would be above the injury and thus those fibers would be damaged.

54
Q

The prefrontal lobotomy is a drastic—and largely outof-
practice—procedure used to disconnect that portion of
the cerebral cortex from the rest of the frontal lobe and
the diencephalon as a psychiatric therapy. Why would this
have been thought necessary for someone with a potentially
uncontrollable behavior?

A

The prefrontal cortex is involved in decision-making functions that lead to motor responses through connections to the more posterior motor regions. These early aspects of behavior are often associated with a person’s personality, do disrupting those connections will lead to severe changes in behavior.