Forbes: Brain Stem Organization

Front 1

What makes up the Rostral Reticular Formation?

Back 1

Midbrain + rostral pons

Front 2

What makes up the Caudal Reticular Formation?

Back 2

Caudal pon + medulla

Front 3

What is the principal function of the Reticular Formation (Rostral RF + Diencephalic nuclei)?

Back 3

Maintaining alert, conscious state in forebrain (part of ARAS)

Front 4

What is the principal function of the Reticular Formation (Caudal RF + CNN + SC)?

Back 4

Many motor, reflex, autonomic functions.
Control of Somatic Motor Functions.
Regulation of Visceral Functions

Front 5

What is the principal function of the Reticular Formation (Raphe nuclei + periaqueductal gray)?

Back 5

Modulation of pain

Front 6

What does the reticulospinal tract do?

Back 6

Provides major indirect or extrapyramidal route for higher centers to control SC somatic motor neurons (espeically reflex activity, postural tone involving skeletal muscle)

Front 7

Describe the "descending autonomic pathway"

Back 7

Hypothalamus & Amygdala --> Reticular Formation --> (via RST and RBT) Preganglionic Sympathetic / ParaSym Neurons

Front 8

What does the descending autonomic pathway influence?

Back 8

All visceral or autonomic functions

Front 9

What happens with the descending autonomic influence is lost (d/t lesion of BS or SC)?

Back 9

* Widespread Horner's Syndrome
* Urinary incontinence
* Disruption of resp/CV function

Front 10

What are autonomic centers in the RF?

Back 10

Involved in control of CV and Resp functions (regulate HR and BP, inspiration/expiration, normal rhythm of breathing)

Front 11

Where are the cardiovascular centers located?

Back 11

Medullary RF (depressor center)
Pontine/Medullary RF (pressor center)

Front 12

Where are the respiratory centers located?

Back 12

Medullary RF (Inspiratory/Expiratory)
Pontine RF (Pneumotaxic center)

Front 13

What does these autonomic centers do?

Back 13

Respond to input from sensory receptors:
1. Baroreceptors (carotid/aortic sinuses)
2. Chemoreceptors in carotid and aortic bodies
3. Stretch receptors in lungs

Front 14

What is the pathway of the input from these receptors?

Back 14

GP and vagal nerves --> caudal solitary nucleus, which communicates with autonomic centers in RF, then pregang paraS/sym neurons (via RBT, RST)

Front 15

REMEMBER:

Back 15

Protect the brain stem since damage to the CV and Resp centers is incompatible with life.

Front 16

What portions of the raphe system are involved with modulating pain?

Back 16

Specific nuclei in the raphe portion of the rostral medulla and caudal pons RF.

Front 17

What does stimulus of the nucleus raphe magnus do?

Back 17

Produces analgesic effect in injured/diseased areas (may last for hours)

Front 18

From what high centers does the RF nuclei (in raphe system) receive input?

Back 18

Hypothalamus, limbic system (via periaqueductal gray matter of midbraine.

Front 19

Where does the raphe spinal tract travel?

Back 19

RF (of brain stem) into dorsolateral funiculus of SC (axons terminate in dorsal horn)

Front 20

What NT is released from raphe spinal tract?

Back 20

Serotonin (into the dorsal horn)
* This activates enkephalinergic interneurons in substantia gelatinosa.
* These transmit pain from 1o aff pain fibers to tract cells, which gives origin to STT

Front 21

Where/how to morphine / other opiates produce their effects?

Back 21

Activation of opiate receptors (in periaqueductal gray, raphe magnus nucleus, superficial laminae (incl. substantia gelatinosa) of DH of SC.

Front 22

Lists the tracts in the ICP

Back 22

Dorsal Spinocerebellar (DSCT)
Cuneocerebellar (CCT)
Olivocerebellar (OCT)
Vestibulocerebellar
Trigeminocerebellar
Reticulocerebellar
Cerebello-vestibular
Cerebello-reticular

Front 23

What 3 structures give input to the inferior olivary nucleus?

Back 23

Cerebral cortex (via cortico-olivary)
Red nucleus (via central tegmental)
Spinal Cord (via spino-olivary)

Front 24

To where does the ION project?

Back 24

Contralateral Cerebellum (via olivocerebellar tract in ICP)

Front 25

Where does the corticopontine tract terminate?

Back 25

In pontine nuclei (basilar pons)

Front 26

Where does the pontocerebellar tract originate, and what does it form?

Back 26

Pontine nuclei
MCP

Front 27

Where does the MLF terminate?

Back 27

On CNN III, IV, VI

Front 28

What are the tracts in the SCP?

Back 28

Cerebello-rubro-thalamic
Ventral (anterior) spinocerebellar
Trigeminocerebellar

Front 29

These pathways go through the central tegmental tract:

Back 29

Reticular formation --> substantia innominata of forebrain & thalamus.
Solitary nucleus (taste input) --> Thalamus & Hypothalamus
Red Nucleus --> Inf Olivary Complex

Front 30

Where does the lateral lemniscus terminate?

Back 30

Nucleus of inferior colliculus

Front 31

Where does most of the output from the red nucleus go?

Back 31

Ventral lateral (some anterior) motor thalamus.

Front 32

From where does the superior colliculus receive information?

Back 32

Retina and occipital cortex (via brachium of superior colliculus.

Front 33

What is the blood supply to the medulla?

Back 33

Vertebrals and their branches

Front 34

What is the blood supply to the pons?

Back 34

Basilar (+ branches)

Front 35

What is the blood supply to the midbrain?

Back 35

Posterior cerebral / posterior communicating (+ branches)

Front 36

What do lesions in the paramedian region affect?

Back 36

Descending motor pathways
Medial lemniscus
Nuclei of cranial nerves III, IV, VI & XII

Front 37

What do lesions in the lateral region affect?

Back 37

Pathways to & from cerebellum
Descending sympathetic pathways (reticulospinal)
Spinothalamic tract
Nuclei of cranial nerves V, VII, VIII, IX & X