Hypothalamus

Question 1

Summarize the main body functions under hypothalamic control

Answer 1

Body temp and febrile response

Food, salt, and water intake

Sexual cycles, sexual orientations, onset of sexual milestones

Circadian rhythms

Sleep

Bodyweight

Stress response

Question 2

Describe the local neuroanatomical relationships of the hypothalamus

Answer 2

Below the hypothalamic sulcus (line formed from the anterior commissure to the posterior commisure)

Question 3

Describe the hypothalamic tracts and note the pathways they participate in

Answer 3

Fornix to mammilary bodies (from hippocampus)

mammilothalamic tract

medial forebrain bundle

tuberoinfundibular

hypothalamo-hypophyseal (pituitary)

Question 4

Explain in general terms (at a systems level) how the hypothalamus acts to maintain
homeostasis – how does it work?

Question 5

Describe the two basic input connections of the hypothalamus

Answer 5

Neural and chemosensory

Question 6

Describe the relationship of the hypothalamus to endocrine and autonomic nervous
systems

Question 7

Describe the specific regulatory mechanisms of the hypothalamus as they pertain to:

Maintenance of body temperature

Question 8

Describe the specific regulatory mechanisms of the hypothalamus as they pertain to:

Circadian rhythms

Question 9

Describe the specific regulatory mechanisms of the hypothalamus as they pertain to:

Sleep

Question 10

Describe the specific regulatory mechanisms of the hypothalamus as they pertain to:

Appetite

Question 11

Describe the specific regulatory mechanisms of the hypothalamus as they pertain to:

Salt and water intake

Question 12

Describe the specific regulatory mechanisms of the hypothalamus as they pertain to:

Reproductive milestones, cycles and sexual behavior

Question 13

Localize basic hypothalamic lesions based on regional signs

anterior vs. posterior, medial vs. lateral

Question 14

Fornix

Answer 14

A hypothalamic tract
From the hippocampus to the mammillary bodies
Shows degenerative changes in Korsakoff’s

Question 15

Mammillothalamic Tract

Answer 15

A hypothalamic tract

From mammillary bodies to anterior thalamus

Question 16

Medial Forebrain Bundle

Answer 16

A part of the hypothalamic tract
Runs through the lateral hypothalamus
Connects the hypothalamus to the brainstem (below) and the basal forebrain, amygdala, and cortex (above)
Damage is thought to affect appetite

Question 17

Hypothalamo-hypophyseal tract

Answer 17

A hypothalamic Tract
Runs from the paraventricular nucleus and supraoptic nuclei –> to the posterior pituitary … via the pituitary stalk

pituitary stalk (aka infundibulum) connects the underside of the hypothalamus to the pituitary gland

Question 18

Describe the main sources of neural inputs to the hypothalamus

Answer 18

Retina
Olfactory system
Spino-hypothalamic inputs
Viscerosensory inputs
Pre-frontal cortex
insula
amygdala
hippocampal formation

Question 19

Describe the main sources of chemosensory inputs to the hypothalamus

Answer 19

CVO’s
Hypothalamic chemosensory neurons
Hypothalamic hormone and steroid receptors

Question 20

What are the two hypothalamic autonomic pathways

Answer 20

DLF (PAG) - axons destined for brainstem
Hypothalamospinal pathway (Central tegmental tract) - axons destined for spinal cord

Question 21

Name the common responses to cold

Answer 21

Increase in metabolism
Shivering
Decreased peripheral blood flow (vasoconstriction)
Changes in hair/fur to retain heat

Question 22

Name the common responses to heat

Answer 22

Sweating
Increased peripheral blood flow
peripheral vasodilation

Question 23

What are the three hypothalamic outputs?

Answer 23

Autonomic
Endocrine
Behavioral Modification (drinking)