Central Nervous System (CNS)

Question 1

CNS

Answer 1

Consists of Brain and Spinal Cord

Integration, decision making, and processing of signals

Question 2

Peripheral Nervous System (PNS)

Answer 2

Consists of nerves and ganglia

Signals traveling to/from targets in the periphery

Question 3

Afferent and Efferent signals

Answer 3

CNS and PNS are connected via a constant feedback loop

Sensory info → AFFerent
incoming info, INTO CNS

Motor info → EFFerent
outgoing info, FROM CNS to PNS

Question 4

CNS

Answer 4

Major Divisions:

Cerebral cortex

Diencephalon

Cerebellum

Brainstem
continues inferiorly as the spinal cord

Question 5

Cerebral Cortex

Answer 5

Outermost layer of brain

Associated w/ higher lever processing and functioning

Divided into right and left hemispheres

Folded to increase SA for info processing
gyri - bumps/folds of cortex
sulci - grooves/indentations
fissure - deep sulcus
longitudinal fissure divides hemispheres

Question 6

Cerebral Cortex: Matter

Answer 6

Each hemisphere is made up of white and gray matter

“Matter” = made up of different parts of CNS cells called NEURONS

Question 7

Grey Matter vs. White Matter

Answer 7

Question 8

Cerebral Cortex: Corpus Callosum

Answer 8

Major white matter tract found beneath the cerebral cortex

Largest collection of white matter w/in brain

Connects left and right hemispheres and carries info received in one hemisphere over to the other

Question 9

Clinical Correlation: Split Brain Syndrome and Hemisphere Dominance

Answer 9

Corpus callostomy: when corpus callosum = surgically severed as a last-resort tx of pt suffering from epilepsy → can stop seizures from spreading from one hemisphere to the other

Pts known as “split brain” pts due to lack of connection between left and right hemispheres (most deficits = language related)

Speech → generated in left hemisphere (dominant hemisphere for language)

Question 10

Cerebral Cortex: Each Hemisphere has 4 Lobes

Answer 10

Frontal = cognition, control of voluntary movement

Parietal = processes info about pain, temp, taste, touch, and vibration

Temporal = processes memories and auditory info

Occipital = primarily responsible for processing visual sensation

Question 11

Key Cortical Areas and their Specific Functions

Answer 11

Question 12

Cerebral Cortex: Central Sulcus

Answer 12

Separates parietal lobe from frontal lobe

Precentral gyrus → represents primary motor cortex in frontal lobe

Post-central gyrus → represents the primary somatosensory cortex in parietal lobe

Question 13

Cortical Homunculus: Motor and Sensory Mapping of Cortex

Answer 13

Question 14

Frontal - Broca’s Area

Answer 14

Function:
motor production of speech and articulation

damage to this area results in “non-fluent aphasia”
^poor or absent grammar // omitting common words // difficulty forming complete sentences // difficulty w/ articulating sounds and words

Question 15

Parietal/Temporal/Occipital = Wernicke’s Area

Answer 15

Function
language interpretation and understanding

damage to this area results in “fluent aphasia”
^results in articulating sentences that have the appropriate cadence but lack the right words // jumbling words together in a seemingly arbitrary sequence // inserting made-up, nonsense-like words into sentences // being unaware that you may be articulating something incomprehensible to others

INDIVIDUALS W/ WERNICKE’S APHASIA ≠ ABLE TO COMPREHEND WHAT IS BEING SAID TO THEM

Question 16

Diencephalon

Answer 16

Large mass of grey matter found between the cerebrum and brainstem

Thalamus → major relay center for all incoming sensory info (EXCEPT olfaction/smell)

Hypothalamus → coordinates autonomic nervous system & pituitary gland to regulate body temp, maintain homeostasis, control appetite, manage sexual behavior, regulate emotional responses

Question 17

Brainstem

Answer 17

Connects cerebrum w/ spinal cord

Coordinates motor control signals sent from brain to body

Controls autonomic functions
HR, RR, BP

• *Composed of 3 Parts:**
• *midbrain**
• *pons**
• *medulla oblongata**

Question 18

Cerebellum

Answer 18

Located posteriorly
Sits inferior to occipital and temporal lobes

“Little brain” in Latin

Coordinates and regulates movement, posture, and balance

Functions in proprioception → the perception or awareness of the position and movement of body
^signals from soft tissues of muscles, tendons, ligaments, skin sent to CNS

Question 19

CNS Imaging

Answer 19

Question 20

CNS Imaging

Answer 20

Question 21

Cortical Injuries

Answer 21

Common Examples:
space occupying lesion // stroke // traumatic brain injury // hematoma // edema

Diagnostic Signs on Imaging:
∆ in radiographic density
abnormal shape compressing/shifting cortical structures
specific pt deficits based on compression of specific cortical regions

Question 22

Cortical Injuries

Question 23

The Spinal Cord

Answer 23

Inferior continuation of the brainstem

Coordinates motor and sensory signals between brain and body
Sensory signals = AFFerent and ASCEND up the cord to the brain

Motor signals = EFFerent and DESCEND down the cord from the brain to the peripheral system

Connected to the PNS via spinal nerves (31 pairs of nerves)

Question 24

Spinal Cord Contd.

Answer 24

Runs from foramen magnum to L1/2 intervertebral disc
in newborn ends at 4th lumbar vertebrae
growth of cord stops at age 5

Conus Medullaris: termination of the spinal cord

Cauda Equina: remaining spinal nerves traveling w/in the canal

Question 25

Internal Anatomy of Spinal Cord

Answer 25

Similar to the cortex (comprised both grey and white matter) * *2 grooves** on the cord which are helpful for orientation * *anterior median fissure (deep opening)** * *posterior median sulcus (shallow line)** Signals ascend/descend the cord via white matter “columns” (**posterior → sensory only // anterolateral → motor&sensory)**

Question 26

Signals of the Nervous System

Answer 26

Question 27

Protection of the CNS

Answer 27

**Bone:** skull // vertebral column **Connective tissues:** meningeal layers ``` **Fluid:** cerebrospinal fluid (CSF) ```

Question 28

Meninges of Brain

Answer 28

Skull **epidural space: NO! ONLY PATHOLOGICALLY** **Dura Mater “tough mother”:** 2 layers: 1. periosteal (adhered to bone) 2. meningeal (forms dural folds for venous sinuses) **subdural space: NO! ONLY PATHOLOGICALLY** **Arachnoid mater:** Named for its “web-like” appearance Arachnoid villus / arachnoid granulations (small protrusions of arachnoid through the dura mater) **subarachnoid space:** where you find CSF **Pia mater:** tightly adhered to neural tissue itself

Question 29

Meninges of Brain Contd.

Answer 29

**Periostal dura** (outer layer) **Meningeal dura** (inner layer) forms folds of tissue that separate cranial cavity into sections separated by “venous sinuses"

Question 30

Meninges of **Spinal Cord**

Answer 30

Vertebral Column **Epidural space:** filled w/ fat for additional protection **Dura mater:** 1 layer only: meningeal layer thicker than other meninges: **Subdural Space:** NO! ONLY PATHOLOGICAL **Arachnoid mater:** named for its “web-like" appearance **Subarachnoid space:** where you find CSF **Pia mater:** tightly adhered to neural tissue itself

Question 31

Meninges of Spinal Cord

Answer 31

Question 32

Injecting into Meningeal Spaces

Answer 32

Question 33

Ventricular System of CNS

Answer 33

Question 34

Ventricles of CNS

Answer 34

Question 35

Flow of CSF w/in Ventricles

Answer 35

Question 36

Flow of the CSF

Answer 36

Question 37

Meninges of Brain

Answer 37