35: Hypothalamus

Question 1

Hypothalamus function

Answer 1

Regulates basic drives, emotional behavior, homeostasis, and endocrine function

Question 2

Examples of homeostasis regulated by hypothalamus

Answer 2

Food intake, fluid and electrolyte balance, body temp, sexual and reproductive behavior, circadian rhythm

Question 3

Embryological origin of hypothalamus

Answer 3

Diencephalon

Question 4

Rostral hypothalamus vs caudal

Answer 4

Rostral: optic chiasms
Caudal: tegmentum and PAG in midbrain

Question 5

What do the walls of the hypothalamus form?

Answer 5

Floor and walls of third ventricle

Question 6

Infundibular stalk

Answer 6

Connects hypothalamus + post pit

Question 7

Three notable areas of the hypothalamus

Answer 7

1. Mammillary bodies
2. Tuber cineureum
3. Median eminence

Question 8

Mammillary bodies location

Answer 8

Posterior hypothalamus, next to cerebral peduncles

Question 9

Tuber cinereum

Answer 9

Swelling between mammillary bodies + optic chiasm

Question 10

Median eminence

Answer 10

From tuber cinereum -> narrows into infundibulum

Question 11

What divides hypothalamus into its lateral and medial zones?

Answer 11

Columns of the fornix

Question 12

Lesion to lateral zone nuclei

Answer 12

Decrease in feeding, weight loss

Question 13

Anterior area of medial zone function

Answer 13

Range of visceral/somatic function, temp regulation

Question 14

Lesion of SON and PVN

Answer 14

diabetes insipidus: increased H2O uptake and increased urination

Question 15

Damage to SCN

Answer 15

Modulation or abolishment of circadian rhythm

Question 16

Lesion to ventromedial nucleus

Answer 16

Excessive eating and weight gain

Question 17

Stimulation vs lesion of dorsomedial nucleus

Answer 17

Stimulation: sham rage
Lesion: decreased aggression and feeding

Question 18

Mammillary body lesion

Answer 18

Inability to process short-term events into long-term memories

Question 19

Overall blood supply to hypothalamus

Answer 19

Small perforating A’s of Circle of Willis

Question 20

Blood supply to anteromedial group vs posteromedial group of hypothalamus

Answer 20

Anteromedial: ACA + ACoA
Posteromedial: PCA + PCoA

Question 21

What does the rostral vs caudal portion of the PCoA supply?

Answer 21

Rostral: tuberal region
Caudal: mammillary region

Question 22

What do MFB and DLF stand for?

Answer 22

MFB: medial forebrain bundle
DLF: dorsal longitudinal fasciculus

Question 23

Connection between mammillary bodies + medial zone -> PAG and RF

Answer 23

Enables hypothalamus to influence emotional aspect of behavior

Question 24

Two tracts that interact between hypothalamus and pituitary

Answer 24

1. Supraopticohypophyseal tract

2. Tuberoinfundibular tract

Question 25

Where are oxytocin and ADH stored before being released into capillary plexus to the post pit?

Answer 25

Herring bodies

Question 26

Tuberoinfundibular tract

Answer 26

PVN -> pituitary, conveying releasing hormones

Question 27

Lesion in anterolateral medulla

Answer 27

Disrupts hypothalamomedullary fibers -> symp outflow to face and head (Horner’s syndrome) or body