Chapter 12: Central Nervous System (CNS) Flashcards
Central Nervous System (CNS)
Brain + Spinal Cord
-performs integration (analysis of stimuli, formulation of appropriate responses)
Regions of the Brain
- Cerebrum
- Diencephalon (inferior to cerebrum)
- Brain Stem
- Cerebellum (next to brain stem)
Cerebrum 3 Parts
- Cerebral Cortex
- Cerebral White Matter (deep to cerebral cortex)
- Basal Nuclei
Nucleus
collection of cell bodies in CNS
Tract
collection of axons in the CNS
“Gray Matter”
neuronal cell bodies + short processes (dendrites)
“White Matter”
axons
Cerebral Cortex
involved in conscious behaviors
- perception (conscious awareness) of sensory information
ex: cortical blindness- don’t have everything at the conscious level to see - voluntary use of skeletal muscle (consciously move a part of your body)
Domain: 3 Types
An area of the cerebral cortex with known functions
- Motor- involved in the voluntary use of skeletal muscle
- Sensory- involved in perceiving sensory info (conscious awareness)
- Association- receive input from other domains
Domain: Motor
involved in the voluntary use of skeletal muscle
motor=movement=voluntary
Domain: Sensory
involved in perceiving sensory info (conscious awareness)
Domain: Association
receive input from other domains
Examples of Motor Domains
- Primary motor area
- Premotor area
- Broca’s area
Motor Domain: Primary motor area
contains neurons called pyramidal cells, which initiate voluntary skeletal muscle movements; this area exerts contralateral control (side)
Motor Domain: Premotor Area
(anterior to primary motor area)
-a “memory bank” for learned, pattern, complex set of movements
ex: remembering how to drive (info stored)
pre- before
Motor Domain: Broca’s Area
(usually in left hemisphere)
-a “memory bank” for production of speech sounds
(remembering how to make diff. consonant + vowel sounds so you don’t have to remember, you voluntarily do it)
-if damaged you have difficulty speaking
Examples of Sensory Domains
- Primary Somatosensory Area
2. Somatosensory Association Area
Sensory Domain: Primary Somatosensory Area
-somatosensation- all sensory modalities except vision, hearing, taste and smell
(ex: touch (fine + deep), pressure, vibration, pain, heat, cold)
(first domain to receive somatosensory info)
-figures out WHERE the info was received
ex: sensory cold hand on the back of the neck
Sensory Domain: Somatosensory Association Area
figures out WHAT KIND of somatosensory information was received
- allows identification by TOUCH
ex: finding your car keys from the same pocket as your phone, figure out what it is by touch
Examples of Association Domains
- Prefrontal Area
2. Wernicke’s Area
Association Domain: Prefrontal Area
involved in: (good at figuring stuff out)
- computation
- understanding
- planning
- complex learning
Association Domains: Wernicke’s Area
involved in producing spoken language
(choose the sequence of words that you are trying to convey in that area)
“word salad”–> throw random words together, if suffer from a mini-stroke in Wernicke’s area
Cerebral White Matter: 3 Types of axons
- Association axon- found entirely within one hemisphere
- Commissural- connects left+ right hemispheres
- Projection axon- connects cerebrum to other areas of the CNS (projects out of cerebrum)
Basal Nuclei
found at the base of the cerebral hemispheres
-regulate force production (especially during fine movements)
(make sure you’re not using more force than necessary)
-start, maintain, and stop repetitive movements (talk and stir at the same time)
Diencephalon contains…
- Thalamus
- Hypothalamus
- Epithalamus
Diencephalon: Thalamus
(personal assistant to cerebral cortex)
-consists of 2 sets of nuclei
-direct impulses to and from specific cortical domains
(make sure sensory info gets sent to the right cortical domain)
ex: make sure visual sensory goes to visual cortex; auditory sensory goes to auditory cortex
Diencephalon: Hypothalamus
(inferior to thalamus)
- a diverse set of nuclei; involved in maintaining homeostasis
- homeostatic control center of the CNS
- in charge of autonomic nervous system (ANS) (in charge of all involuntary effectors)
- in charge of endocrine system (which releases hormones)
Diencephalon: Epithalamus
-contains choroid plexuses (modified blood vessels)
-make cerebrospinal fluid (CSF) which,
-contains O2 + nutrients
-cushions CNS (floats in this stuff)
(helps brain from smashing into skull)
Contains Pineal Gland
-releases melatonin; involved in sleep-wake cycle
(if you have a lot of melatonin it makes you feel like its late; tells you its time to sleep)
Brain Stem consists of….
- Midbrain
a. Tegmentum
b. Tectum - Pons
- Medulla Oblongata
Brain Stem: Midbrain
consists of a tegmentum (ventral) and a tectum (dorsal)
Brainstem: Midbrain; Tegmentum
- cerebral peduncles
- contain the axons of the pyramidal cells
- Red Nuclei- motor area used by cerebellum to coordinate muscle
- Substantia Niagra (dark stuff)- prevents unwanted/unnecessary skeletal muscle contractions
ex: Parkinson’s disease; more tetanus, gets more action potential, hands tap, head shakes)
Brainstem: Midbrain; Tectum
Corpora Quadrigemina (body with 4 parts)
Superior Colliculi (top 2 bumps/nuclei):
-perform visual localization
(take info coming from left + right eye to give you a 3 dimensional outlook)
Inferior Colliculi:
-perform auditory localization
(compose sounds that reach right + left ears to determine where a sound came from
-control skeletal muscles involuntary (move neck to find where the sound came from)
Brain Stem: Pons
“bridge”
- consists of ascending(sending info up) and descending (sending info down) axons
- also contains urinary centers (when to use bathroom), respiratory centers (control breathing rate)
Brain Stem: Medulla (Oblongata)
oxxo
x- contains pyramid cell axons
o- (lateral)- Olives- conduct info about body + limb position to cerebellum
(tells your cerebellum what position your body is in to help coordinate movements)
Medullary Nuclei: In medulla
- Cochlear Nuclei
- Vestibular Nuclear Complexes
- Gracile Nuclei, Cuneate Nuclei
- Ventral Respiratory Group (VRG)
- Cardiovascular Centers
Medullary Nuclei: Cochlear Nuclei
help integrate auditory info
Medullary Nuclei: Vestibular Nuclear Complexes
balance centers (take over muscles so you don't fall down)
Medullary Nuclei: Gracile Nuclei, Cuneate Nuclei
send body/ limb position information to thalamus cerebral cortex
(know consciously what position your body is in)
Gracile- lower body (gracilis in lower leg)
Cuneate- upper body
Medullary Nuclei: Ventral Respiratory Group (VRG)
causes inspiration (taking in; air) -tells you (diaphragm) to breathe every 4 seconds
Medullary Nuclei: Cardiovascular Centers
influence heart rate, blood pressure
Cerebellum
excellent at predicting/ calculating the outcome of a series of events
- helps skeletal muscles produce coordinated movement (tells muscles how to do something)
ex: alcohol hits cerebellum first + hard + cant maintain balance properly or its hard to move properly
Cerebellum has 2 hemispheres, each with 3 lobes:
- Anterior lobe
- Posterior lobe
Both:
-contain neurons that receive body position
-information from and can influence movements in specific body parts
3.Flocculonodular lobe
-maintain balance during movement
Cerebellum Communicates with brainstem via Cerebellar Peduncles
- As cerebral cortex sends action potentials (that initiate voluntary movements) toward spinal cord, the pons uses the Middle Cerebellar Peduncles to inform cerebellum
- Cerebellum gets body position information from Olives (medulla) via Inferior Cerebellar Peduncles
- Cerebellum calculates the series of contractions needed to execute the desired movement
- Cerebellum sends these “calculations” to the red nuclei of the midbrain via Superior Cerebellar Peduncles
- Red Nuclei adjust the movements being initiated by cerebral cortex
Functional Brain Areas
- Limbic System
2. Reticular Formation (Reticular Activating System) (RAS)
Functional Brain Areas: Limbic System
(found throughout cerebrum, diencephalon)
-affecting (emotional)center of the CNS
-produces physiological changes that deal with your mental state (feelings)
ex: face gets red when you’re angry
-engages in emotional thinking (intuition)
(no proof to back it up, but that’s how you feel)
Functional Brain Areas: Reticular Formation (Reticular Activating System) (RAS)
(found in thalamus + Core of Brainstem)
- involved in cortical arousal (keeps you paying attention/ focused)
- acts as a “sensory filter”
ex: sending lots of action potentials to language + auditory cortex to understand the speech + sound, keep you paying attention
Spinal Cord
- sends impulses between brain + PNS
- sends somatosensory information from PNS to brain
- sends impulses from the brain to effectors (voluntary + involuntary)
- integrates reflexes
ex: when the doctor hits your patellar ligament it reflexes, or moves body part from hot surface–> fast reflex
Components of a Reflex Arc
- Dorsal Root
- Dorsal Horn
- Lateral Horn
- Ventral Horn
- Ventral Root
Components of a Reflex Arc: Dorsal Root
contains sensory neurons
brings sensory info in
Components of a Reflex Arc: Dorsal Horn
contains interneurons (neurons that perform integration) (what does sensory mean?)
Components of a Reflex Arc: Lateral Horn
contains cell bodies of autonomic motor neurons (activate motor neurons)
talk to effectors (talk to involuntary effectors)
Components of a Reflex Arc: Ventral Horn
contain cell bodies of somatic motor neurons
which communicate with skeletal muscle
Components of a Reflex Arc: Ventral Root
contains the axons of the autonomic + somatic motor neurons
Spinal Cord Tracts
tracts in white matter (funiculi)
=white matter which conducts information TO and FROM brain
ascending tract- conduct info from spinal cord to brain
descending tract- conduct into from brain to spinal cord
Examples of Ascending Tracts
- Cuneate and Gracile Fasciculi
- Anterior + Posterior Spinocerebellar
- Spinothalamic
Example of Ascending Tract: Cuneate and Gracile Fasciculi
send body position information from cuneate and gracile nuclei of medulla to the thalamus; from thalamus, this proprioceptive information reaches the cortex to allow conscious proprioception- conscious awareness of body position
Example of Ascending Tract: Anterior + Posterior Spinocerebellar
Send body position information to cerebellum via the Olives and Inferior Cerebellar Peduncles; allows Subconscious Proprioception
Example of Ascending Tract: Spinothalamic
send many kinds of somatosensory information (temperature, touch, pain, pressure) to thalamus; from thalamus, this information reaches the cerebral cortex
Examples of Descending Tracts
- Anterior and Lateral Corticospinal
- Other listed descending Tracts
- Tectospinal
- Vestibulospinal
Examples of Descending Tracts: Anterior + Lateral Corticospinal
Send action potentials FROM the primary motor area of the cerebral cortex to the spinal cord in order to cause voluntary skeletal muscle movement (includes cerebral peduncles, pyramids of medulla)
Examples of Descending Tracts: Other Listed Descending Tracts
Send action potentials from brain areas OTHER THAN the CEREBRAL CORTEX to the spinal cord, in order to produce involuntary skeletal muscle movement
ex:
- Tectospinal
- Vestibulospinal
Examples of Descending Tracts: Other listed descending tracts: Tectospinal
move the head and eyes to keep visual and/ or auditory tract of where something is in relation to the body in three-dimensional space
Examples of Descending Tracts: Other listed descending tracts: Vestibulospinal
used by the vestibular nuclear complexes of the medulla to move muscles in order to keep balance
