Chapter 9 - Reticular Formation & Limbic system

Question 1

3 longitudinal Columns of the Reticula Formation

Answer 1

1. Median column
2. Medial column
3. Lateral column

“M”edian”L” has L meaning it is more “L”ateral than median with no “L”

Question 2

Size of neurons in:
(1) Median longitudinal column
(2) Medial longitudinal column
(3) Lateral longitudinal column

Answer 2

(1) Intermediate sized neurons
(2) Large sized neurons
(3) Small sized neurons

Media”N” for i”N”termediate, media”L” one L for “Large”. “L”atera”L” two Ls for sma”LL”

Question 3

Reticular Formation Relations:
(1) superiorly
(2) inferiorly
(3) laterally

Answer 3

(1) cerebral cortex
(2) interneurons of spinal cord gray matter
(3) cerebellum

Question 4

Reticular Formation Functions (#7)

Answer 4

1. control of skeletal muscle
2. control of facial expression muscle
3. control of somatic and visceral sensations
4. control of ANS
5. control of endocrine system
6. influence biologic clock
7. reticular activating system (consciousness)

Question 5

Location of reticular formation

Answer 5

At the center of the cerebrospinal axis

at the brinstem (?)

Question 6

Components of the Hippocampal Formation

Answer 6

1) hippocampus
2) dentate gyrus
3) parahippocampal gyrus

Hippocampus is a curved elevation of gray matter that extends throughout the entire length of the floor of the inferior horn of the lateral ventricle

Question 7

Hippocampus

Answer 7

A curved elevation of gray matter that extends throughout the entire floor of the inferior horn of the lateral ventricle

Question 8

Limbic System Structures

Answer 8

1. amygdaloid nucleus
2. parahippocampal gyri
3. hippocampal formation
4. subcallosal
5. cingulate
6. mammillary bodies
7. anterior thalamus nuclei

Question 9

Limbic system connecting pathways

Answer 9

*alveus
*fimbria
*fornix
*mammillothalamic tract
*stria terminalis

Question 10

white nerve fibers extending from hippocampus converging into the fimbria

Answer 10

alveus

Question 11

Notch of gray matter that lies between the parahippocampal gyrus and the fimbria

Answer 11

Dentate gyrus

Question 12

Thin vestigial layer of gray matter that covers the superior surface of the corpus callosum (below cingulate gyrus)

Answer 12

Indusium griseum

posteriorly, the dentate gyrus accompanies the fimbria and becomes continuous to the indusium griseum

Question 13

Between the hippocampal fissure and the collateral sulcus;

continuous with the hippocampus along the medial edge of the temporal lobe

Answer 13

parahippocampal gyrus

Question 14

Nuclei groups of the amygdala

Answer 14

*basolateral group (larger)
*corticomedial group (smaller)

Question 15

Connects the Right and left crura of the fornix to form the body of the fornix

Answer 15

commissure of the fornix

Question 16

Foramen of Monro

The body of the fornix splits anteriorly into two columns of the fornix that curves anteriorly and inferiorly over the foramen of monro

Answer 16

Interventricular foramen connects the lateral ventricles and the 3rd ventricle

Question 17

Major output pathway of the limbic system

Answer 17

Hypothalamus

Question 18

Emotional behavior influenced by the limbic system

Answer 18

Fear, anger, sexual behavior

Question 19

Converts short term memory to long term memory

Answer 19

Hippocampus

Question 20

When new short term memory cannot be converted to long term but previous memory is unaffected

50 First Dates

Answer 20

Anterograde Amnesia

Question 21

Expanded anterior end of the hippocampus

Answer 21

Pes Hippocampus

Question 22

Net of nerve cells and fibers strategically placed to connect important nerve tracts and nuclei

Answer 22

Reticular formation

Question 23

Reticular meaning

Answer 23

Having form a net

Question 24

Afferent Projections to the Reticular Formation
(1) from spinal
(2) from cranial nerve nuclei
(3) from cerebellum
(4) from basal nuclei

Answer 24

(1 - From spinal)
Spinoreticular, spinothalamic, medial lemniscus

(2 - From cranial nerve nuclei)
Vestibular, acoustic, visual pathway, primary cortex of the frontal lobe, somesthetic cortex from parietal lobe

(3 - From cerebellum)
Cerebroreticullar pathway

(4 - From basal nuclei)
subthalamic, hypothalamic, thalamic nuclei, corpus striatum, and limbic system

Question 25

Efferent projections from the Reticular Formation (1) to the brainstem & spinal cord (2) to sympathetic outflow & the craniosacral parasympathetic outflow of ANS (3) to other parts of the brain (4) to the cerebral cortex

Answer 25

(1 - to brainstem and spinal cord) reticulobulbar & reticulospinal (2 - to the sympathetic outflow and the craniosacral parasympathetic outflow of the ANS) (3 - to the corpus striatum, cerebellum, red nucleus, substantia nigra, tectum, nuclei of the thalamus, subthalamus, and hypothalamus) (4 - to cerebral cortex)

Question 26

Reticular formation is a net of nerve cells and fibers that receives and sends signals to influence ()

Answer 26

* skeletal muscle activity (movement) * somatic and visceral sensations * autonomic and endocrine system * level of consciousness

Question 27

Limbic System ## Footnote Initially reffering to a group of structures that lie in the border zone between the cerebral cortex and the hypthalamus - now includes other structures beyond border zone

Answer 27

## Footnote Important in "BE DiM" - Behavior, Emotion, Drive, Memory

Question 28

Limbic System - label

Answer 28

1) subcallosal gyrus 2) cingulate gyrus 3) parahippocampal gyrus 4) uncus

Question 29

Limbic System - label

Answer 29

1) subcallosal gyrus 2) cingulate gyrus 3) parahippocampal gyrus 4) uncus

Question 30

Limbic System - label

Answer 30

1) mammillary body 2) fornix - column 3) fornix - body 4) fornix - commissure 5) fornix - crus 6) fimbria (of the hippocampus) 7) hippocampus 8) dentate gyrus 9) pes hippocampus 10) amygdaloid body 11) mammillothalamic tract 12) anterior thalamic nucleus

Question 31

Named due to it ressembling a seahorse

Answer 31

Hippocampus

Question 32

Resembles an almond

Answer 32

amygdaloid nucleus

Question 33

At which area do fibers of the fornix decussate to join the hippocampi of the two sides?

Answer 33

commissure of the fornix

Question 34

Fornix relations: (1) anteriorly (2) inferiorly

Answer 34

(1) undersurface of the corpus callosum by the septum pellucidum (2) tela choroidea and the ependymal roof of the 3rd ventricle

Question 35

(True/False) The parahippocampal gyrus is 6-layered. As it traces into the hippocampus there is a gradual transition in to 3 layers

Answer 35

True ## Footnote 3 layers: superficial molecular layer, pyramidal layer, & polymorphic layer

Question 36

(True/False) Similar to the hippocampus, the dentate gyrus is composed of a superficial molecular layer, pyramidal layer, & polymorphic layer

Answer 36

False The dentate gyrus is composed of 3 layers but the pyramidal layer is replaced by the granular layer

Question 37

The afferent connections of the hippocampus are divided into 6 groups namely: | "from () to the hippocampus"

Answer 37

(1) from cingulate gyrus (2) from septal nuclei (3) from one hippocampus to the other (4) from the indusium griseum (5) from entorhinal area or olfactory associate cortex (6) from the dentate and parahippocampal gyri

Question 38

Efferent connections of the hippocampus | "From the hippocampus to ()"

Answer 38

(1) mammillary body > medial nucleus (2) anterior nuclei of the thalamus (3) to tegementum of the midbrain (4) to septal nuclei, lateral preoptic area, and anterior part of the hypothalamus (5) stria medullarix thalami > habernular nuclei

Question 39

Damage to the reticular formation causes

Answer 39

loss of consciousness or coma

Question 40

MOA of lessening worse symptoms of schizophrenia

Answer 40

Blocking dopamine receptors of the limbic system e.g. phenothiazine

Question 41

Kluver-Bucy syndrome

Answer 41

patient becomes docile showing no evidence of fear and anger with increased appetite and sexual activity ## Footnote Association: unilateral or bilateral destruction of the amygdaloid nucleus results in a decrease in aggressiveness, emotional instability, and restlessness with increased interest in food and hypersexuality

Question 42

The following statements concern the reticular formation: (a) Reticulobulbar and reticulospinal tracts form the afferent pathways from the reticular formation to the motor nuclei of the cranial nerves and the anterior horn cells of the spinal cord, respectively. (b) The reticular formation extends through the neuroaxis from the spinal cord to the midbrain. (c) The main pathways through the reticular formation may easily be traced from one part of the CNS to another using silver stains. (d) Superiorly, the reticular formation is relayed to the cerebral cortex. (e) Afferent pathways project into the reticular formation from only a few parts of the CNS.

Answer 42

D

Question 43

The following statements concern the functions of the reticular formation: (a) It Influences the activity of the a and 'Y motor neurons. (b) It opposes the actions of the vestibular spinal tract. (c) It does not bring about reciprocal inhibition during contraction of the prime mover muscles. ( d) It plays no part in maintaining the tone of the antigravity muscles. (e) It cannot modulate reflex actMty.

Answer 43

A

Question 44

The following statements concern the functions of the reticular formation: (a) It does not affect the reception of pain. (b) It cannot influence all ascending pathways to the suprasplnal levels. (c) By means of Its reticulobulbar and retlculospinal tracts, it can control parasympathetic and sympathetic outflows. (d) It has no effect on biologic rhythms. (e) It does not influence the degree of wakefulness of an individual.

Answer 44

C

Question 45

Anatomically, the following structures collectively form the limbic system: (a) Amygdalold nucleus, red nucleus, and vestibular nuclei (b) Pulvinar of the thalamus and the substantia nigra (c) Hippocampal formation (d) Cingulate gyrus and uncus (e) Subcallosal, cingulate, and parahippocampal gyri, hippocampal formation, amygdaloid nucleus, mammillary bodies, and anterior thalamic nuclei

Answer 45

E

Question 46

The following statements concern the efferent connections of the hippocampus: (a) They arise from the small granular cells of the cortex. (b) They travel through the fornix. (c) None of the fibers enter the mammillary body. (d) The fibers within the fomlx pass posterior to the interventricular foramen. (e) Some of the fibers end in thalamic posterior nuclei.

Answer 46

B

Question 47

The following statements concern the functions of the limbic system: (a) It is not concerned with fear and anger. (b) It is concerned with visual experiences. (c) The hippocampus is concerned with recent memory. (d) The limbic system plays an important role in olfactory function. (e) It directly influences the activity of the endocrine system.

Answer 47

C

Question 48

Answer 48

(1) body of fornix (2) dentate gyrus (3) parahippocampal gyrus (4) uncus