9 - Diencephalon (Exam 2)

Question 1

What is the diencephalon composed of?

Answer 1

3rd ventricle
Thalamus
Hypothalamus

Question 2

What is a brief summary of the thalamus?

Answer 2

Gatekeeper to the cortex

Everything goes through the thalamus before it enters or leaves the cerebral cortex (except for smell)

Question 3

What are the 7 main thalamic nuclei?

Answer 3

1. LGN - lateral geniculate nucleus
2. MGN - medial geniculate nucleus
3. VPL - ventral posterior lateral nucleus
4. VPM - ventral posterior medial nucleus
5. VA - ventral anterior nucleus
6. VL - ventral lateral nucleus
7. Pulvinar nucleus

Question 4

What is the function of the LGN?

Answer 4

Visual pathway
Layers I and II are magno
Layers III, IV, V, and VI are parvo
Ipsilateral temporal retinal fibers - II, III, V
Contralateral nasal retinal fibers - I, IV, VI

Question 5

What is the function of the MGN?

Answer 5

Auditory pathway

Question 6

What is the function of the VPL?

Answer 6

Relay all sensory information from the body

Question 7

What is the function of the VPM?

Answer 7

Relay all sensory information from the face

Question 8

What are 3 examples of sensory relay nuclei?

Answer 8

1. Ventral posterior nucleus (VPL and VPM)
2. Medial geniculate nucleus (MGN)
3. Lateral geniculate nucleus (LGN)

Question 9

What is a brief summary of the VA and VL nuclei?

Answer 9

Motor relay nuclei
Input from basal ganglia and cerebellum
Project to primary motor/motor association areas
Under tonic inhibition

Question 10

What is an example of an association nucleus?

Answer 10

Pulvinar nucleus

Question 11

What is the function of the pulvinar nuclei?

Answer 11

Vision processing (visual salience, working visual memory)
Auditory processing

Question 12

What 4 association areas do the pulvinar nuclei have connections in?

Answer 12

1. Frontal
2. Parietal
3. Temporal
4. Occipital

Question 13

What is a brief summary of the hypothalamus?

Answer 13

Responsible for body temperature regulation

Links ANS, endocrine system, emotions, and somatic function

Question 14

Anatomically, what is the hypothalamus a part of?

Answer 14

Diencephalon

Question 15

Functionally, what is the hypothalamus a part of?

Answer 15

Limbic system

Question 16

How large is the hypothalamus?

Answer 16

Very small

Only weighs about 4 grams

Question 17

What are the 4 major regions of hypothalamic nuclei?

Answer 17

1. Anterior area
2. Lateral nucleus
3. Middle area
4. Posterior area

Question 18

Clinically, which is more important for hypothalamic nuclei - general area or specific nuclei?

Answer 18

General area

Question 19

What is the anterior region responsible for in the hypothalamus?

Answer 19

Heat loss
Sleep
Hormone regulation
Magno/ parvo cells

Question 20

What is the middle region responsible for in the hypothalamus?

Answer 20

Emotions
Eating and drinking
Hormone regulation

Question 21

What is the posterior region responsible for in the hypothalamus?

Answer 21

Heat gain
Wakefulness
Memory

Question 22

What is another name for the pituitary gland?

Answer 22

Hypophysis

Question 23

How many lobes does the pituitary gland have?

Answer 23

Two lobes
Anterior lobe
Posterior lobe

Question 24

What is the neural connection between the hypothalamus and the posterior lobe of the pituitary gland called?

Answer 24

Neurohypophysis

Question 25

What is the vascular connection between the hypothalamus and the anterior lobe of the pituitary gland called?

Answer 25

Adenohypophysis

Question 26

Feedback systems regulate endocrine function - how are long feedback loops and short feedback loops different?

Answer 26

Long feedback loops involve plasma hormone levels dictating the amount of production and secretion Short feedback loops have a direct connection between the pituitary gland and hypothalamus

Question 27

Which region of the hypothalamus is involved with cooling the body down (heat loss mechanisms)?

Answer 27

Anterior hypothalamus

Question 28

Which region of the hypothalamus is involved with heating the body up (heat gain mechanisms)?

Answer 28

Posterior hypothalamus

Question 29

Where does each portion of the hypothalamus send signals to regarding "heat loss mechanisms" or "heat gain mechanisms"?

Answer 29

The ANS

Question 30

Where does each portion of the hypothalamus send signals to regarding a change in clothes, turning the heat on, or opening windows?

Answer 30

The cerebral cortex

Question 31

How would a lesion to the anterior hypothalamus effect body temperature?

Answer 31

Hyperthermia | A result of loss of "heat loss mechanisms"

Question 32

How would a lesion to the posterior hypothalamus effect body temperature?

Answer 32

Hypothermia | A result of loss of "heat gain mechanisms"

Question 33

How would a large, bilateral lesion to the hypothalamus effect body temperature?

Answer 33

Body temperature can't be regulated | Similar to cold-blooded animals

Question 34

Which region of the hypothalamus tells the body "I'm hungry!"?

Answer 34

Lateral hypothalamus

Question 35

Which region of the hypothalamus tells the body "I'm full!"?

Answer 35

Medial hypothalamus

Question 36

How would a lesion to the lateral hypothalamus effect the body?

Answer 36

Anorexia | Loss of "I'm hungry!" messages

Question 37

How would a lesion to the lateral hypothalamus effect the body?

Answer 37

Obesity | Loss of "I'm full!" messages

Question 38

What type of mechanisms help keep the body's water in balance?

Answer 38

Neural and hormonal mechanisms

Question 39

What is a neural mechanism example of water balance?

Answer 39

Lateral hypothalamus is stimulated to induce drinking

Question 40

What is a hormonal mechanism example of water balance?

Answer 40

Increased osmolarity of the blood results in increased ADH and therefore urine retention Decreased osmolarity of the blood results in decreased ADH and therefore more urination

Question 41

What would a lesion to the posterior lobe of the pituitary gland present as?

Answer 41

Diabetes insipidus | Inadequate output of ADH therefore excessive urination

Question 42

What is referred to as the body's "master clock"?

Answer 42

The suprachiasmal nucleus (SCN)

Question 43

What is the role of the SCN?

Answer 43

Neurons project to pineal gland low light stimulates melatonin production high light inhibits melatonin production

Question 44

What modulates the activity of the SCN?

Answer 44

Input from the retinhypothalamic tract

Question 45

How many hours in the rhythm of activity of SCN neurons?

Answer 45

24 hours