L2 Review of Nervous System Structure & Development; Cranial Bones

Question 1

Answer 1

Question 2

_____________ (named according to overlying skull bone)

_____________ (folds)

_____________ (furrows)

Answer 2

Lobes (named according to overlying skull bone)

Gyri (folds)

Sulci (furrows)

Question 3

Two groups of bones in the Cranium?

Answer 3

Neurocranium (protects the brain)

Viscerocranium (assist in formation of face)

Question 4

Identify the Neurocranial Bones (6)

Answer 4

Question 5

Identify the Viscerocranial Bones (8)

Answer 5

Question 6

Answer 6

Question 7

Answer 7

Question 8

Answer 8

Question 9

__________: Groups of nerve cell bodies with similar anatomical connections and functions

PNS vs. CNS?

Answer 9

Nuceli: Groups of nerve cell bodies with similar anatomical connections and functions

GANGLION in peripheral = NUCLEI in CNS

Question 10

_________: Groups of nerve processes with common connections and functions following the same course

• also called fasciculus, peduncle, lemniscus
• Named according to direction of impulses:

CNS vs. PNS?

Answer 10

Tracts: Groups of nerve processes with common connections and functions following the same course

• also called fasciculus, peduncle, lemniscus
• Named according to direction of impulses:
  –e.g. corticospinal tract from “cerebral cortex” to “spinal cord”
  –e.g. spinothalamic tract from “spinal cord” to “thalamus”

NERVE in peripheral = TRACT in CNS

Question 11

Answer 11

Question 12

Organization of Sensory Pathways: for most somatic senses there are THREE neurons between receptor and perception at cerebral cortex:

• First Order (Primary) Neurons: Send axons into cord or brainstem. Cell body lies in the _____________
• Second Order (Secondary) Neruon: Located in CNS. Axons Projects to _____________ (_____________)
• Third Order (Tertiary) Neuron: Cell body located within specific nucleus of _____________. Axons project to ___________ cerebral cortex (_________________ Cortex)

Answer 12

Organization of Sensory Pathways: for most somatic senses there are THREE neurons between receptor and perception at cerebral cortex:

• First Order (Primary) Neurons: Send axons into cord or brainstem. Cell body lies in the GANGLION
• Second Order (Secondary) Neruon: Located in CNS. Axons Projects to Thalamus (Contralaterally)
• Third Order (Tertiary) Neuron: Cell body located within specific nucleus of thalamus. Axons project to Ipsilateral cerebral cortex (Primary Somatosensory Cortex)

Question 13

Organization of Motor Pathways: Serquence of TWO neurons between cerebral cortex and effector skeletal muscle

Upper Motor Neurons:

• Cell Body Located in ____________
• Axon Projects via ______________ to Brainstem (_______________)
• Relays to Ventral Horn of spinal cord

Lower Motor Neuron:

• Cell body is located in ____________
• Axons projects to ______________
• AKA the ____________________________________

Answer 13

Organization of Motor Pathways: Serquence of TWO neurons between cerbal cortex and effector skeletal muscle

Upper Motor Neurons:

• Cell Body Located in Motor Cortex
• Axon Projects via Internal Capsule to Brainstem (Decussates)
• Relays to Ventral Horn of spinal cord

Lower Motor Neuron:

• Cell body is located in Ventral Horn
• Axons projects to Muscle Unit
• AKA the Final Common Pathway

Question 14

In general, each cerebral hemisphere perceives sensations from, and controls movements of, the _____________ side of the body

Answer 14

In general, each cerebral hemisphere perceives sensations from, and controls movements of, the contralateral side of the body

Question 15

Answer 15

Question 16

Subdivisions of Primitive Brain

_______________ (Forebrain)

• _______________: Paired vesicles that grow from forebrain => Cerebrum
• ______________: Original part of forebrain => Eye Cup, Thalamus/Hypothalamus

______________ (Midbrain) => ____________

________________ (Hind Brain)

• __________________ =>Pons, Cerebellum
• __________________ (Caudal) => Medulla Oblongota

Answer 16

Prosencephalon (Forebrain)

• Telencephalic Vesicles: Paired vesicles that grow from forebrain =>Cerebrum
• Diencephalon: Original part of forebrain => Eye Cup, Thalamus/Hypothalamus

Mesencephalon (Midbrain) => Midbrain (remains unchanged)

Rhombeencephalon (Hind Brain)

• Metencephalon =>Pons, Cerebellum
• Myelencephalon (Caudal) => Medulla Oblongata

Question 17

Extreme Cranial End of the primitive brain is the ________________

Answer 17

Extreme Cranial End of the primitive brain is the Lamina Terminalis

Question 18

What part of the primitive brain gives rise to the Medulla Oblongota?

Answer 18

Rhombeencephalon (Hind Brain)=> Myelencephalon (Caudal) => Medulla Oblongota

Question 19

What part of the primitive brain gives rise to the Pons/Cerebellum?

Answer 19

Rhombeencephalon (Hind Brain) => Metencephalon => Pons, Cerebellum

Question 20

What part of the primitive brain gives rise to the Eye Cup and Thalamus/Hypothalamus?

Answer 20

Prosencephalon (Forebrain)=> Diencephalon (Original part of forebrain) => Eye Cup, Thalamus/Hypothalamus

Question 21

What part of the primitive brain gives rise to the Cerebrum?

Answer 21

Prosencephalon (Forebrain)=> Telencephalic Vesicles (Paired vesicles that grow from forebrain) =>Cerebrum

Question 22

Telencephalic Vesicles (____________) encloses _____________

Answer 22

Telencephalic Vesicles (Cerebral Hemispheres): LATERAL VENTRICLES

Question 23

Diencephalon (___________) encloses _________________

Answer 23

Diencephalon (Thalamus): THIRD VENTRICLE

Question 24

Mesencephalon (___________) encloses ___________________

Answer 24

Mesencephalon (Midbrain): CEREBRAL AQUEDUCT

Question 25

Metencephalon (____________) encloses ______________________

Answer 25

Metencephalon (Pons & Cerebellum): _UPPER_ PART OF FOURTH VENTRICLE

Question 26

Myencephalon (___________) encloses _______________________

Answer 26

Myencephalon (Medulla Oblongata): _LOWER_ PART OF FOURTH VENTRICLE

Question 27

What encloses the Lateral Ventricles?

Answer 27

Telencephalic Vesicles (Cerebral Hemispheres)

Question 28

What encloses the Third Ventricle?

Answer 28

Diencephalon (Thalamus)

Question 29

What encloses the Cerebral Aquaduct?

Answer 29

Mesencephalon (Midbrain)

Question 30

What encloses the UPPER Part of the Fourth Ventricle?

Answer 30

Metencephalon (Pons & Cerebellum)

Question 31

What encloses the LOWER Part of the Fourth Ventricle?

Answer 31

Myencephalon (Medulla Oblongata)

Question 32

**Mechanism of Neural Tube Formation** * Neural tube Closure BEGINS in the ________ Region and then proceeds _________ and __________ * Temporarily leaves openings called __________ at either end of the tube (anterior & posterior; communicate with amniotic sac)

Answer 32

**Mechanism of Neural Tube Formation** * Neural tube Closure BEGINS in the **Cervical Region** and then proceeds CAUDALLY and CRANIALLY * Temporarily leaves openings called **Neuropores** at either end of the tube (anterior & posterior; communicate with amniotic sac)

Question 33

Timing of Closure of the Neural Tube?

Answer 33

**Day 25**: Cranial (anterior) Neuropore closes **Day 25 + 2**: Caudal (posterior) Neuropore closes

Question 34

Failure of CAUDAL Closure of Neural Tube?

Answer 34

**Spina Bifida**

Question 35

Failure of CRANIAL Closure of Neural Tube?

Answer 35

**Anencephaly**

Question 36

Failure of Closure of ENTIRE Neural Tube?

Answer 36

**Rachischisis**

Question 37

Answer 37

Question 38

Answer 38

Question 39

Answer 39

Question 40

Surface ectoderm and roof plate produce a protein called bone morphogenetic protein 4 (BMP4) which induces ______ neurone formation and inhibits ________

Answer 40

Surface ectoderm and roof plate produce a protein called bone morphogenetic protein 4 (BMP4) which induces SENSORY neurone formation and inhibits MOTOR

Question 41

Notochord and floor plate produce a transcription factor called Shh which induces _______ neurone formation and inhibits _________

Answer 41

Notochord and floor plate produce a transcription factor called Shh which induces MOTOR neuron formation and inhibits SENSORY

Question 42

Cerebellum develops from a special part of the _______________ alar plate called the _______________

Answer 42

Cerebellum develops from a special part of the **Mesencephalon's** alar plate called the **Rhombic Lip**