Lesson 4 - Brainstem Nuclei and Tracts

Question 1

Where is the brainstem located?

Answer 1

between the cerebrum and spinal cord

Question 2

The brainstem is a ——— for tracts running between higher and lower neural centres

Answer 2

pathway

Question 3

The brainstem consists of the ———,———- and medulla oblongata (each region is about 1 inch in length)

Answer 3

midbrain, pons

Question 4

The brainstem consists of deep —– matter surrounded by ——-matter fiber tracts

Answer 4

grey
white

Question 5

The brainstem produces ———— behaviours necessary for survival

Answer 5

autonomic

Question 6

The brainstem lies upon the ——-portion of the occipital bone and is connected to and mostly covered by the ———–

Answer 6

basal
cerebellum

Question 7

Caudally in the brainstem, the medulla is continuous with the spinal cord just below the f————– ———–

Answer 7

foramen magnum

Question 8

Rostrally in the brainstem, the midbrain is connected with the ——— of the forebrain

Answer 8

diencephalon

Question 9

The brainstem is responsible for many vital functions of life, such as———-, consciousness, blood ——-, heart rate, and sleep.

Answer 9

breathing
pressure

Question 10

The brainstem contains many critical collections of white and grey matter. The grey matter within the brainstem consists of nerve cell ——–s and forms many important ———- ——–.

Answer 10

bodies
brainstem nuclei

Question 11

The Organisation of the Brainstem:

Contains numerous ascending and descending ——- ——–s

Some originate in ——- ———-(ascending), some in ————- ———- (descending) and others originate or terminate in brain stem nuclei.

Certain brain stem nuclei called ———- ———- nuclei, receive or send fibres into cranial nerves, 10 pairs of which (III-XII) attach to surface of brain stem.

Answer 11

fibre tracts
spinal cord
cerebral hemisphere
cranial nerve

Question 12

Development of the brainstem:

During embryonic development, the ——— portion of the neural tubes undergoes significant growth and differentiation to form the brain.

By week 5, the primary brain vesicles (———, ———- and ———-) can be identified

By week 7, 5 secondary brain vesicles are produced by division of prosencephalon (———,———) and the rhombencephalon (metencephalon, myelencephalon)

The ———– develops into the pons and the overlying cerebellum

The ———– develops into the medulla oblongata

The midbrain, pons and medulla oblongata form the brainstem

Answer 12

rostral
prosencephalon, mesencephalon and rhombencephalon
telencephalon, diencephalon
metencephalon
myelencephalon

Question 13

The central nervous system uses ——— and ———- ——–s to communicate with the external environment.

Answer 13

ascending and descending pathways

Question 14

The CNS:

The ascending sensory pathway is responsible for ————s and is composed of the posterior column pathway, the ———- pathway and the spinocerebellar pathway.

The descending motor pathway is composed of the ———–(conscious) system and the————— (unconscious) system.

Answer 14

sensations
spinothalamic

pyramidal
extrapyramidal

Question 15

Describe the basic Overview of a Motor Pathway

Answer 15

The pyramidal tracts (pass through the pyramids of the medulla) are responsible for the conscious, voluntary control of the body and face muscles. They can be divided into two descending tracts.

Corticospinal tract:
Carries information from the cerebral cortex to the spinal cord and controls movement of the torso, upper and lower limbs.
Its projections have a strong influence on the activity of groups of spinal motor neurones, which innervate distal muscles of the hands and feet.
Most of the fibers (~85%) cross the midline of the medulla in the decussation of the pyramids in the brain stem and then descend through the spinal cord in the lateral corticospinal tract, while the other 15% cross within the spinal cord at the level they terminate and are carried within the medial corticospinal tract.

Corticobulbar tract:
Composed of the uppermotor neuronsof thecranial nerves.
Themusclesof the face, head and neck are controlled by the corticobulbar system, which terminates on motor neurons withinbrainstemmotor nuclei.

Question 16

Primary Motor Pathway

FROM the —–
TO the brainstem (———- tract) and spinal cord (———– tracts)

• the lateral ———– tract conveys commands to the body e.g. playing piano, tap dancing etc.
• the anterior ———- tract controls trunk muscles e.g. core exercises

Answer 16

cortex
corticobulbar
corticospinal

corticospinal
corticospinal

Question 17

Describe the basic overview of a sensory pathway

Answer 17

Theascending tracts (somatosensory pathways or systems)refer to the neural pathways by which sensory information from the peripheral nerves is transmitted to the cerebral cortex.
Functionally, the ascending tracts can be divided into the type of information they transmit – conscious or unconscious:

Conscious tracts– comprised of the dorsal column-medial lemniscal pathway (posterior column pathway) and the spinothalamic pathway (anterolateral system).
Unconscious tracts– comprised of the spinocerebellar tracts.

Question 18

Basic Overview of a Sensory Pathway:

All 3 levels (brain, brainstem and spinal cord) receive inputs from s———— ———–s

In addition, —————- ————-involving 2 independent subcortical systems modulate activity at the brainstem and cortical levels i.e. the cerebellum and basal ganglia

Importantly, there are no ——–connections between the cerebellum and basal ganglia and the lower motor neurons of the spinal cordwhich is known as the “——– ———– pathway”

Answer 18

sensory receptors
feedback loops
direct
final common

Question 19

The first two cranial nerves attach to the ————- while
The remaining 10 CNs attach to the ——— ———– (CNIII-CNXII).

Answer 19

forebrain
brain stem

Question 20

All cranial nerves emerge from the ———- aspect of the brainstem with the exception of the trochlear nerve (CN IV), which arises from the ———– surface of the brain stem.

Answer 20

anterior
dorsal

Question 21

Cranial nerves (CNIII-CNXII) are associated with various nuclei within the brain stem, called ——- ———- nuclei.

Answer 21

cranial nerve

Question 22

Cranial nerve nuclei either receive cranial nerve ——–s or contain the cell bodies of ——— neurons that have axons leaving the brain in the cranial nerves

Answer 22

afferents
efferent

Question 23

Afferent Nuclei of the Brainstem:

Fibers carrying general sensory information (touch, pressure, pain, temperature) from the head enter the brain through the ———- nerve at the pons and terminate in the ———— ————– ———–.

Fibres conveying the special senses of motion, positional sense and hearing run in the ————— nerve. They terminate in the ————– and ———— nuclei, respectively in the medulla.

———- afferents including taste fibres terminate in the nucleus solitarius in medulla.

Answer 23

trigeminal
trigeminal sensory nucleus

vestibular cochlear
vestibular and cochlear
Visceral

Question 24

Efferent nuclei of the brain stem:

Nuclei of the somatic ———– cell column (III,IV,VI,XII)
- Oculomotor nucleus, trochlear nucleus, abducens nucleus, hypoglossal nucleus.

Nuclei of the ———— cell column
- Innervates striated muscles derived from the bronchial arches
Trigeminal motor nucleus, facial motor nucleus, nucleus ambiguus.

Nuclei of the ————— cell column
- Consists of preganglionic parasympathetic neurons that send axons into the III,VII, IX and X cranial nerves.
- ———- ————– nucleus, superior and inferior salivatory nuclei, dorsal motor nucleus of the vagus.

Answer 24

efferent
branchiomotor
parasympathetic
Erdinger-Westphal

Question 25

Components of the brainstem: ------------ ------------- Pathways (dorsal) - Relay nuclei, tracts ----------- ----------- Pathways (ventral) - Tracts, motor nuclei brainstem (the CNs) ------------ Pathways - Tracts, cerebellar afferent and efferent nuclei ---------- -------------- sensory and motor tracts - Cranial nerve nuclei, nerve entry and exit points

Answer 25

Sensory Ascending Motor Descending Cerebellar Cranial nerve

Question 26

A structural abnormality in the ------------ is one of the most life threatening pathologies that can be encountered, as the brainstem controls much of the involuntary nervous system that keeps the heart beating and the lungs breathing

Answer 26

brainstem

Question 27

The midbrain is divided into dorsal and ventral portions at the level of the ------------- -------------

Answer 27

cerebral aqueduct

Question 28

The dorsal portion of the midbrain is known as the -------- which consists largely of the inferior and --------- -----------. The ventral portion of the midbrain is known as the -----------. It is bounded ventrally by the ------------ -----------.

Answer 28

tectum superior colliculi tegmentum crus cerebri

Question 29

Crus cerebri - consists of descending ----------- ---------fibres that have left cerebral hemisphere via internal capsule. 50% = corticobulbar and corticospinal fibres. On either side of these fibres lie --------------- fibres – terminate in pontine nucleus of pons which establish connections with cerebellum and are involved in coordination of movement

Answer 29

cortical efferent corticopontine

Question 30

The Midbrain: The ---------- ----------s serving the extra ocular muscles have their cell bodies in the ocular motor nucleus which lies at the base of the ------------ -----------.

Answer 30

motor neurons periaqueductal grey

Question 31

The trochlear nerve contains only ------------- ------------- neurons which arise in the trochlear nucleus in the ventral part of the ------------ ----------.

Answer 31

somatic motor periaqueductal grey

Question 32

What is the role of the red nucleus in the midbrain?

Answer 32

motor control, muscle tone, posture

Question 33

Substantia nigra contains the --------- --------------- which consists of melanin-containing neurons that produce dopamine. Degeneration in ---------- ----------- is associated with Parkinson’s disease

Answer 33

pars compacta pars compacta

Question 34

What is the anterior and posterior section of the midbrain?

Answer 34

cerebral aqueduct

Question 35

The ------------- -------------, which is located on the dorsal surface of the midbrain, is composed of two superior colliculi (vision) and two inferior colliculi (hearing)

Answer 35

corpora quadrigemina

Question 36

The superior colliculi are part of the visual system, relaying input from the optic tract to the -------- ---------- bodies of the ------------

Answer 36

lateral geniculate thalamus

Question 37

The ----------- ------------ are part of the auditory pathway and send information to the medial geniculate bodies of the thalamus

Answer 37

inferior colliculi

Question 38

What is the reticular activating system?

Answer 38

present throughout the brainstem and is involved in sleep wake cycles

Question 39

The inferior colliculus coordinates with the -------------- ------------ in orienting the gaze toward or away from visual and auditory stimuli

Answer 39

superior colliculus

Question 40

----------- nuclei in the midbrain contains numerous blood vessels and receives info from the cerebrum and cerebellum and issues subconscious motor commands concerned with muscle tone and posture

Answer 40

Red

Question 41

Name some nuclei of the midbrain

Answer 41

Red Nuclei Nuclei of CRN III and IV (oculomotor and trochlear) Substantia nigra

Question 42

In the midbrain, lateral to the red nucleus is the melanin containing ------------ ----------- which secretes dopamine to inhibit the excitatory neurons of the basal nuclei

Answer 42

substantia nigra

Question 43

Name some of the tracts in the midbrain

Answer 43

Motor tracts Sensory axons Cerebral peduncles

Question 44

Motor tracts, including the fibres of the --------- system, pass downward on midbrain's ventral surface

Answer 44

pyramidal

Question 45

Sensory axons, including those of the ---------- tract ascend along the dorsal midbrain

Answer 45

spinothalamic

Question 46

The ---------- ------------s (crus cerebri). The efferent projections include ------------ (cortex to brain stem) and corticospinal (cortex to spinal cord) axons

Answer 46

cerebral peduncles corticobulbar

Question 47

Where is the pons located?

Answer 47

between the midbrain and the medulla oblongata

Question 48

What is the role of the Pons?

Answer 48

It handles unconscious processes and jobs, such as your sleep-wake cycle and breathing. It also contains several junction points for nerves that control muscles and carry information from senses in your head and face

Question 49

Name some nuclei in the Pons?

Answer 49

- Sensory and motor nuclei for 4 cranial nerves Trigeminal (V), Abducens (VI), Facial (VII), and Vestibular (VIII) - Apneustic and pneumotaxic centres work with the medulla to maintain respiratory rhythm - Other nuclei, including raphe nuclei and Reticular activating system

Question 50

Superior, middle and inferior cerebellar peduncles - tracts that process and relay info to/from the ------------

Answer 50

cerebellum

Question 51

Motor and sensory tracts transverse the anterior surface of the ------. The sensory fibres are located posterior to the -------- fibres.

Answer 51

Pons motor

Question 52

Nuclei in the medulla are associated with ----------- control, cranial nerves, and motor/sensory --------s

Answer 52

autonomic relays

Question 53

Autonomic Nuclei of the Medulla Oblongata: Cardiovascular centres: Alter the rate and force of cardiac ----------s, alter the tone of vascular --------- muscle Respiratory rythmicity centres: receive input from the --------- Additional centers: ---------, deglutition, coughing, hiccupping, and sneezing

Answer 53

contractions smooth pons Emesis

Question 54

Name the sensory and motor nuclei of 5 cranial nerves in the medulla

Answer 54

Vestibular (VIII) Glossopharyngeal (IX) Vagus (X) Accessory (XI) Hypoglossal (XII)

Question 55

Relay Nuclei of the Medulla: Nucleus ---------- and nucleus --------- pass somatic sensory information to the thalmus --------- nuclei relay info from the spinal cord, cerebral cortex, and the brainstem to the cerebellar cortex

Answer 55

gracilis cuneatus Olivary

Question 56

Tracts of the Medulla: - Ventrally, 2 ridges (the ---------- ---------s) are visible These are formed by the large motor ------------- tracts Right above the medulla -D-SC junction, most of these fibres cross-over (------------)

Answer 56

medullary pyramids corticospinal decussate

Question 57

Name this structure based on its description "Bottom-most part of your brain. Where your brain and spinal cord connect, Key conduit for nerve signals to and from your body. Helps control vital processes like your heartbeat, breathing and blood pressure"

Answer 57

Medulla Oblongata