nervous system pt 2 Flashcards
an involuntary reaction in response to a stimulus applied to
the periphery and transmitted to the CNS.
Reflexes
neuronal pathway by which a reflex occurs.
Reflex Arc
is the basic functional unit of the nervous system because it it the smallest, simplest pathway capable of receiving a stimulus yielding a response.
Reflex Arc
5 basic components of a relflex arc
- Sensory receptor
- sensory neuron
- interneuron
- motor neuron
- effector organ
Simple reflex arcs have only four
components because the reflex does not
involve __
interneurons
A ___ involves synapses
of two or more neurons.
polysynaptic reflex
is to remove a limb or another body part from a painful stimulus.
withdrawal reflex (flexor reflex)
simplest reflex
also called patellar reflex, is a classic example of the stretch reflex involving the spinal cord.
Knee– Jerk Reflex
3.Sensory neurons will synapse ->
interneurons -> motor neurons.
(Polysynaptic)
Withdrawal reflex
Sensory neurons will synapse to the
motor neurons. (Monosynaptic)
Knee-jerk reflex
1.Activation of Pain Receptors
Withdrawal Reflex
1.Sensory receptors activation
Knee– Jerk Reflex
two or more neurons synapse with the same
postsynaptic neuron.
Converging Pathway
the axon from one neuron divides and synapses
with more than one other postsynaptic neuron
Diverging Pathway
Sensory functions (2)
- Ascending Tracts
- Sensory Areas of the Cerebral Cortex
3 ascending tracts
- spinothalmic
- dorsal column
- spinocerebellar
body position
proprioception
Pain, temperature, light touch, pressure, tickle, and itch sensations to the thalamus and on to the cerebral cortex
Spinothalamic
proprioception, touch, deep pressure, and vibration
Dorsal column
Propiroception to cerebellum
spinocerebellar
Ascending tracts project to specific regions of the cerebral cortex, called
____, where sensations are perceived.
primary sensory areas
or general sensory area, is
located in the parietal lobe posterior to the central sulcus.
primary somatic sensory cortex (primary somatosensory cortex)
primary sensory areas include the ____ in the occipital
lobe,
visual cortex
primary sensory areas include the ___ in the temporal lobe
primary auditory cortex
primary sensory areas include the taste
area in the __.
insula
Cortical areas immediately adjacent to the primary sensory areas, called
____, are involved in the process of recognition.
association areas
Association areas (3)
auditory association areas, somatic sensory association area,
and visual association area.
is located in the posterior portion of the
frontal lobe, directly anterior to the central sulcus
primary motor cortex
is where motor functions are
organized before they are actually initiated in the primary motor cortex
premotor area
The motivation and foresight to plan and initiate movements occur in the
anterior portion of the frontal lobes, called the
pre-frontal area.
motor areas in most anterior area to the posterior most (3)
- pre-frontal area
- premotor area
- primary motor cortex
Descending tracts project ____ from upper motor neurons in the
cerebral cortex to lower motor neurons in the spinal cord and brainstem;
directly
Descending tracts project from basal nuclei, the cerebellum, or the cerebral
cortex through the brainstem to lower motor neurons in the spinal cord.
indirectly
Direct descending tracts:
- lateral corticospinal
- Anterior corticospinal
Indirect Descending tracts (5)
- rubrospinal
- reticulospinal
- vestibulospinal
- tectospinal
Muscle tone and skilled movements, especially of hands
lateral corticospinal
muscle tone and movement of trunk muscles
anterios corticospinal
movement coordination
rubrospinal
posture adjustment, especially during movement
reticulospinal
posture and balance
vestibulospinal
movement in response to visual reflexes
tectospinal
include involuntary and voluntary movements.
* Upper motor neurons in the cerebral cortex connect to lower motor
neurons in the spinal cord or cranial nerve nuclei.
Somatic motor functions
sensory functions (4)
⚬ Motor Areas of the Cerebral Cortex
⚬ Descending Tracts
⚬ Basal Nuclei
⚬ Cerebellum
help plan, organize, and coordinate motor movements and
posture.
Basal
Nuclei
People with __exhibit increased muscle tone and
exaggerated, uncontrolled movements when at rest.
basal nuclei disorders
is involved in balance, muscle tone, and muscle
coordination.
cerebellum
Through its _____, the cerebellum compares the intended
action to what is occurring and modifies the action to eliminate
differences
comparator function
If the cerebellum is __, muscle tone decreases and fine motor
movements become very clumsy.
damaged
receives sensory input from and controls
muscular activity in the left half of the body
Right cerebral hemisphere
receives sensory input from and controls
muscular activity in the right half of the body
Left cerebral hemisphere
connection between two hemisphere.
Commissures
The largest
commissure is the
corpus callosum.
In most people, the speech area is located in the __
left cerebral cortex
located in the parietal lobe.
Responsible for understanding speech
Sensory speech (Wernicke’s) area
located in the frontal lobe. Responsible for
producing speech.
Motor (Broca’s) speech area
absent
or defective speech or language comprehension
aphasia
Different levels of
consciousness can be revealed
by different patterns of
___ in the brain
electrical activity
a recording device
which records brain’s electrical
activity.
Electroencephalogram (EEG)
EEG patterns can be detected as wavelike patterns known as
brain waves
brain waves
awake, quiet resting state with eyes closed
alpha waves
brain waves
intense mental activity
beta waves
brain waves
deep sleep
delta waves
brain waves
frustration
theta waves
3 stages of memory
- working memory
- short-term memory
- long-term memory
lasts only a few second to minutes
Working Memory
can be retained for few minutes to few days
Short-term Memory
can be retained permanently.
Long-term Memory
long-term memory two (2) subdivisions:
*Declarative
*Procedural
or explicit memory, involves the retention of facts, such as names, dates, and places
declarative memory
or reflexive memory, ionvolves the development of motor skills, such as riding a bicycle.
Procedural memory
The olfactory cortex and certain deep cortical regions and nuclei of the
cerebrum and the diencephalon are grouped together under the title
limbic system.
influences long-term declarative memory, emo- tions,
visceral responses to emotions, motivation, and mood.
limbic system
The limbic system is connected to, and functionally associated with, the
hypothalamus.
There are _ pairs of cranial nerves
12
cranial nerves are categorized into (2)
Sensory and motor
special senses, such as vision, and the more general senses,
such as touch and pain in the face
Sensory
somatic motor and parasympathetic
Motor
comprises motor neu- rons that carry action
potentials from the CNS to the periphery.
autonomic nervous system (ANS)
In ANS, two neurons in series extend from the CNS to the effectors.
⚬ Pre-ganglionic neuron
⚬ Pos-ganglionic neuron
Further, the ANS is composed of two divisions
⚬ Sympathetic Division
⚬ Parasympathetic division
Preganglionic cell bodies lie in the thoracic and upper lumbar region of
the spinal cord.
Sympathetic Division
Sympathetic Division
The ganglia is located near the
spinal cord.
Postganglionic cell bodies are located in the sympathetic chain ganglia
or in collateral ganglia
Sympathetic Division
Preganglionic cell bodies are associated with some of the cranial and
sacral nerves.
Parasympathetic Division
Parasympathetic Division
The ganglia is located near the
effector organs
Postganglionic cell bodies are located in the terminal ganglia, either
near or within target organs.
Parasympathetic Division
Functions of the Sympathetic Division (3)
- Responses to stressful situations
- Fight or flight responses
- Increases heart rate, respiratory rate, glucose, pupil dilation
Functions of the Parasympathetic Division
- Responses to relaxing situations
- Rest and Digest
- SLUDD: Salivation, Lacrimation, Urination, Defecation and Digestion
