Hypothalamus & Limbic System Flashcards

(63 cards)

1
Q

Hypothalamus is involved in the mediation of:

A
  • Autonomics
  • Neuroendocrine (Pituitary and Pineal Glands)
  • Behavioral functions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Structures located near Hypothalamus:

A
  • Epithalamus
  • Mammillary body (posteroinferior)
  • Anterior Commissure
  • Optic Chiasm
  • Infundibulum with Pituitary Gland
  • Forms floor and inferior walls of third ventricle
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Anteromedial Hypothalamus produces ____ activity

A

Parasympathetic
(ex. satiety, sleep, heat dissipation to decrease temperature)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Posterolateral Hypothalamus produces _____ activity

A

Sympathetic
(ex. hunger, wakefulness, heat conservation to increase body temperature)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What Nuclei are located in the Hypothalamus?

A
  • Lateral
  • Anterior
  • One in the PreOptic area
  • Suprachiasmatic
  • Paraventricular
  • Ventromedial
  • Posterior
  • Arcuate
  • Supraoptic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Lateral Nucleus of Hypothalamus

A
  • Sense a drop of glucose (hunger)
  • Lesion makes you Lean
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Anterior Nucleus of Hypothalamus

A
  • Cooling via Parasympathetic
  • Sense elevation of temperature
  • Increases sweating and dilates superficial vessels
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Nuclei in Preoptic Area of Hypothalamus

A
  • Releases GnRH
  • Influences reproduction and sexual behavior
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Suprachiasmatic Nucleus of Hypothalamus

A
  • Circadian rhythm
  • Can function independently
  • Can be regulated by the Ganglion Cells of CN II
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Paraventricular Nucleus of Hypothalamus

A

Produces Oxytocin and ADH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Ventromedial Nucleus of Hypothalamus

A
  • Sense elevated glucose (satiety)
  • Lesion makes you Very Massive
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Posterior Nucleus of Hypothalamus

A
  • Senses temperature drop (heating)
  • Has sympathetic center
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Arcuate Nucleus of Hypothalamus

A

Secretes Dopamine directly to the Pituitary Gland where it inhibits prolactin secretion in adenohypophysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Supraoptic Nucleus of Hypothalamus

A
  • Secretes ADH and Oxytocin
  • Senses drop in water concentration (thirst)
  • Located in Posterior Pituitary Gland
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The major efferents of Suprachiasmatic Nucleus project to the ___ ___

A

Pineal Gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

During the night, fibers from the SCN release ___ in the Pineal Gland which stimulate the pinealocytes, triggering the production of ____

A
  • NE
  • Melatonin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Supraopticohypophysial Tract

A

Axons carry ADH and Oxytocin into Posterior Pituitary where it is stored in Herrying Bodies and released if needed (i.e hypothalamus osmoreceptors sense lack of water in blood and CSF)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Two main pathways from the Hypothalamus that are the source of most of the central control of autonomic functions:

A
  • Medial Forebrain Bundle
  • Dorsal Longitudinal Fasciculus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

The Medial Forebrain Bundle and the Dorsal Longitudinal Fasciculus connect the Hypothalamus with:

A

the major parasympathetic nuclei in the brain stem and the preganglionic (central) neurons of the thoracolumbar spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Medial Forebrain Bundle

A
  • Anterior area for parasympathetic activity
  • Goes to S2-S4
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Dorsal Longitudinal Fasciculus

A
  • Sympathetic
  • Major output pathway of the hypothalamus that descends through the gray matter of the brain stem and into the spinal cord T1-L2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Lesion of hypothalamus is noticeable mostly in ____ lesion

A

Bilateral
- Typically results in autonomic and neuroendocrine dysfunction (ex. temperature, thirst, etc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

4 Main Limbic Structures

A
  • Amygdala
  • Hippocampus
  • Cingulate Gyrus
  • Parahippocampal Gyrus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Importance of Limbic Structures

A
  • Emotional responses
  • Drive-related behavior
  • Memory
  • Smell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Fornix
- White matter between lateral and 3rd ventricles - Connects hippocampus to mammillary bodies
26
Hippocampus converges to form:
Fimbria of Fornix
27
Fimbria come together to form the:
Crus of Fornix
28
At Anterior Commissure, Body of Fornix splits into:
Columns of Fornix
29
Major role of Hippocampus
Formation of new memory (learning memory)
30
Papez Circuit
Hippocampus --> Mammillary Bodies --> Anterior Thalamic Nuclei --> Cingulate Cortex --> Entorhinal Cortex --> Hippocampus *primary nuclei of circuit: mamillary bodies
31
Role of Papez Circuit
Assists with spatial and episodic memory consolidation and storage
32
What happens if there is damage to the Fornix or Mammillary Bodies?
Amnesia
33
Mammillary Bodies
- One of the primary nuclei of the Papez Circuit - Assist with emotion and reward behaviors and goal-directed behaviors - Primary function is recollective memory - Memory consolidation occurs here -- processing short-term memory into long-term memory
34
What happens if there is a lesion to the Mammillary Bodies?
Anterograde Amnesia -- inability of retention of newly acquired memory; has no difficulty in remembering events occurring months or years before the lesion
35
Fornix is situated between what ventricles?
Between the Lateral and Third Ventricles
36
Fornix bifurcates at the level of the ___ ___ with the ___ fibers projecting to the ___ ___
- Anterior Commissure - Postcommissural - Mammillary Bodies
37
Korsakoff Psychosis (Syndrome)
- Caused by Thiamine (Vitamin B1) Deficiency (usually from chronic alcoholism - Leads to degeneration of the Mammillary Bodies - Lesion is bilateral - Irreversible condition characterized by triad: anterograde amnesia, confabulation, personality changes (reckless behavior)
38
Anterograde Amnesia
- Inability to create new memory - Function of the mammillary bodies with the hippocampus
39
Confabulation
Act of filling in gaps in memory with fabrications that are believed to be true
40
___ ____connect Amygdala with the ___
- Stria Terminalis - Hypothalamus (Lateral Nucleus)
41
What are the main efferent fibers of the Amygdala?
Stria Terminalis
42
Role of Amygdala
- Form memories related to emotional events - Facilitate long-term memory formation (together with hippocampus) - Convert and retain learning from pleasure or fear responses - Help us tell what other people express: aggression, love, indifference, etc
43
Causes of Kluver-Bucy Syndrome
- Result of trauma or surgery (for epilepsy) to temporal lobe - Can also be caused by Herpes Encephalitis
44
Kluver-Bucy Syndrome
- Associated with damage to both amygdala resulting in abnormalities in memory, social and sexual functioning and idiosyncratic behavior - Diminished ability to visually recognize object, loss of normal fear and anger responses - Associated with Hyperphagia, Hypersexuality, and Hyperorality
45
Hyperphagia
Eating a lot even if person is not hungry; sometimes eats objects that are not actually food
46
Hypersexuality
Extremely urgent sexual desire
47
Hyperorality
Tendency to examine things by mouth; taste, chew, put everything in their mouth
48
Anosmia
- Loss of smell due to a viral infection of the olfactory mucosa, obstruction of the nasal passages or may be congenital - Lesions occur due to shearing of CNI or tumors in the floor of the anterior cranial fossa
49
Phantosmia (Olfactory Hallucination)
Distortion in a smell experience or the perception of a smell when no odor is present
50
Causes of Phantosmia
- Abnormal sequence of neuronal activity - Lesion of anterior/medial temporal lobe -- hippocampus, amygdala, or medial dorsal thalamic nuclei
51
Two major dopaminergic areas of the brain:
- Substantia Nigra - Ventral Tegmental Area
52
Vental Tegmental Area (VTA)
- Located medial to the Substantia Nigra - Role in all behavioral and mental activities in which dopamine is released in our brain (reward, motivation, addiction)
53
Two of the most prominent efferents that project from the VTA:
- Mesolimbic - Mesocortical
54
Mesolimbic Pathway
Travels from VTA to Ventral Striatum (Nucleus Accumbens)
55
Mesocortical Pathway
Travels from VTA to Cortical Areas
56
Schizophrenia
- Dopaminergic neurons in the VTA play a role in this disorder - Associated with high levels of dopamine
57
ADHD
Linked to low dopamine activity in the VTA
58
Integrity of the ___ is crucial to proper brain function
VTA
59
Central Diabetes Insipidus
- Condition in which the kidneys are unable to concentrate urine because of a lack of circulating ADH - Low levels of ADH are due to either decreased production within the hypothalamus or decreased release from the Posterior Pituitary Gland - Present with Polyuria (too much urine), nocturia (increased urination at night), and polydipsia (thirst)
60
Hyperthermia
- May occur if there is a lesion (stroke or CNS damage) in the Anterior Nucleus of the Hypothalamus, which is involved in thermoregulation, specifically cooling the body down - Damage to this region prevents the body from being able to cool itself - Works via stimulation of the Parasympathetic NS
61
Functional Hypothalamic Amenorrhea
- Primary cause of secondary amenorrhea (cessation of menses) - Results from decreased pulsation of GnRH from a nuclei of the PreOptic Area that occurs during times of severe physical or psychological stress - Most commonly associated with eating disorders or overexercise
62
Effect of Lesion to the PreOptic Area
Reduction or abolition of sexual drive
63
Hyperprolactinemia
- Elevated levels of Prolactin (hormone of adenohypophysis) in the blood - Most common cause is a prolactin-secreting pituitary adenoma, but also can be caused by loss of inhibitory dopamine secretion by the hypothalamus - Can occur when dopaminergic neurons from the arcuate nuclei of the hypothalamus are damaged or if the infundibulum is transected during surgery - Sxs: galactorrhea (milk discharge), oligoamenorrhea, erectile dysfunction