Central Nervous System

Question 1

Brain arises from…

Answer 1

Rostral part of the neural tube

Question 2

3 week PRIMARY brain vesicles in 4 week old embryo

Answer 2

Prosencephalon (forebrain)
Mesencephalon (midbrain)
Rhombencephalon (hindbrain)

Question 3

What secondary vesicles do the primary ones give rise to?

Answer 3

Prosencephalon divides into the telencephalon and diencephalon
Mesencephalon remains undivided
Rhombencephalon divides into metencephalon and myelencephalon

Question 4

How does the adult brain develop from the secondary brain vesicles

Answer 4

Telencephalon gives the cerebral hemispheres
Diencephalon becomes thalamus, hypothalamus, and epithalamus
Metencephalon becomes pons and cerebellum
Myelencephalon becomes medulla oblongata

Question 5

Ventricles of the brain

Answer 5

Expansions of the brain's central cavity
Filled with cerebral spinal fluid
Lined with ependymal cells
Continuous with each other
Continuous with the central canal of the spinal cord

Question 6

Location of the ventricles:

1. Lateral ventricles
2. Third ventricle
3. Cerebral aqueduct
4. Fourth ventricle

Answer 6

1. Located in cerebral hemispheres. Horseshoe shaped from bending of the cerebral hemispheres
2. Lies in diencephalon. Connected with lateral ventricles by interventricular foramen
3. Connects 3rd and 4th ventricles
4. Lies in hindbrain. Connects to the central canal of the spinal cord

Question 7

4 regions of the brain

Answer 7

Brainstem (midbrain, pons, medulla)
Cerebellum
Diencephalon
Cerebral hemispheres

Question 8

2 main fissures

Answer 8

1. Transverse fissures (separates cerebrum and cerebellum)

2. Longitudinal fissure (separates cerebral hemispheres)

Question 9

Sulci vs Gyri

Answer 9

Sulci are grooves

Gyri are ridges

Question 10

What does the central sulcus divide? What are the 2 gyri it is bordered by called?

Answer 10

Divides the frontal and parietal lobes

Bordered by precentral gyrus and postcentral gyrus

Question 11

3 general kinds of functional areas

Answer 11

Sensory areas
Association areas
Motor areas

Question 12

Multimodal association areas

Answer 12

Receive and integrate input from multiple regions of the cerebral cortex
Higher level functions
Ex: you feel a key in your pocket, these areas tell you what keys are

Question 13

Motor cortex

Answer 13

Plans and initiates voluntary motor functions

Question 14

Broca’s area

Answer 14

Left frontal lobe

Can understand everything and can say words, but cannot put words in a sentence that makes sense

Question 15

Wernicke’s area

Answer 15

Left temporal lobe
Cannot understand words, but can speak and hear completely fine
Cannot make sense of a sentence

Question 16

Primary somatosensory cortex

Answer 16

Projection is contralateral

Cerebral hemispheres receive input from the opposite side of the body

Question 17

Primary motor cortex

Answer 17

Specific pyramidal cells control specific areas of the body

Face and hand muscles are controlled by many pyramidal cells

Question 18

Somatotopy

Answer 18

Body is represented spatially in the primary motor cortex

Question 19

Which sides of the central sulcus are the motor vs sensory cortex

Answer 19

Motor map in precentral gyrus

Sensory map in postcentral gyrus

Question 20

3 types of tracts

Answer 20

Commissures
Association fibers
Projection tracts

Question 21

Commissures

Answer 21

Composed of commissural fibers
Allows communication between cerebral hemispheres
Corpus callosum is the largest commissure

Question 22

Association fibers

Answer 22

Connect different parts of the same hemisphere

Parts of Wernicke’s and Broca’s areas are connected by these fibers

Question 23

Projection tracts (2)

Answer 23

From the cortex to the rest of the NS
Internal capsule: projection fibers form a compact bundle - passes between thalamus and basal nuclei
Corona radiata: superior to the internal capsule - fibers run to and from the cerebral cortex

Question 24

Basal nuclei/ganglia

Answer 24

A group of nuclei deep within the cerebral white matter
Formed from caudate nucleus, putamen, globus pallidus
Involved in motor control
Receives input from many cortical areas
Substantia nigra also influences it

Question 25

3 functions of basal ganglia

Answer 25

Start, stop and regulate intensity of voluntary movements Select appropriate muscles for a task and inhibit others Estimate the passage of time

Question 26

Thalamus

Answer 26

80% of the diencephalon Contains ~ 12 major nuclei Acts as a relay station for incoming sensory message Every part of brain communicating with cerebral cortex relays signals through thalamic nuclei! Nuclei organize and amplify or tone down signals

Question 27

``` What type of information does the: 1. Ventral posterolateral nuclei 2. Medial geniculate body 3. Lateral geniculate body receive? ```

Answer 27

1. Act as relay stations for the sensory information ascending to the primary sensory areas of the cerebral cortex 2. Receives auditory input and links to the auditory cortex 3. Receives visual input and transmits to the visual cortex

Question 28

Epithalamus

Answer 28

Forms part of the roof of the third ventricle Consists of a tiny group of nuclei Includes the pineal gland

Question 29

Pineal gland

Answer 29

Secretes melatonin Under influence of hypothalamus Aids in control of circadian rhythm

Question 30

Cerebral aqueduct

Answer 30

Central cavity of the midbrain

Question 31

Cerebral peduncles

Answer 31

``` Located on the ventral surface of the brain Contain pyramidal (corticospinal) tracts ```

Question 32

Corpora quadrigemina

Answer 32

On dorsal side of midbrain Act in visual and auditory reflexes Largest nuclei Divided into superior and inferior colliculi

Question 33

Superior vs inferior colliculi

Answer 33

Superior: nuclei that act in visual reflexes Inferior: nuclei that act in reflexive response to sound

Question 34

Periaqueductal gray matter (location, 2 functions)

Answer 34

Surrounds the cerebral aqueduct | Involved in fight or flight reaction, mediates response to visceral pain

Question 35

Function of: 1. Medial lemniscus 2. Reticular formation 3. Crus cerebri of cerebral peduncle

Answer 35

1. Project from neurons in medulla to thalamus - carries sensory information 2. Collection of nuclei - has functions in posture, movement, arousal, etc 3. Where the pyramidal tracts descend down through your body

Question 36

Pontine nuclei

Answer 36

Connect portions of the cerebral cortex and cerebellum | Send axons to cerebellum through the middle cerebellar peduncles

Question 37

Folia

Answer 37

Ridges of the cerebellum

Question 38

3 lobes of the cerebellar hemispheres

Answer 38

Anterior Posterior Flocculonodular lobe (tiny)

Question 39

3 regions of the cerebellum

Answer 39

Cortex (gray) Arbor vitae (internal white matter) Deep cerebellar nuclei - deeply situated gray matter

Question 40

3 tracts connecting the cerebellum to the brainstem

Answer 40

Superior cerebellar peduncles: to midbrain Middle cerebellar peduncles: to pons Inferior cerebellar penduncles: medulla

Question 41

3 types of info the cerebellum receives to coordinate body movements

Answer 41

Info on equilibrium Info on current movements of limbs, neck, and trunk Info from cerebral cortex

Question 42

2 layers of the dura

Answer 42

``` Periosteal layer (connects to the skull) Meningeal layer (connected to periosteum) Fused except to enclose the dural sinuses ```

Question 43

Arachnoid Mater

Answer 43

Located beneath the dura Arachnoid villi are where CSF can move back into the blood stream Allows CSF to pass into the dural blood sinuses

Question 44

Pia Mater

Answer 44

Delicate connective tissue | Clings tightly to the surface of the brain