Pituitary and Hypothalamus

Question 1

The preoptic area is derived from the:

Answer 1

Telencephalon

Question 2

The medial preoptic nucleus produces:

Answer 2

Gonadotropin-releasing hormone (anterior pituitary will release LH and FSH)

Question 3

The lateral hypothalamic nucleus is also referred to as _______

Answer 3

a “feeding center” (destruction causes weight loss, stimulation promotes feeding)

Question 4

What are the 3 regions in the medial zone?

Answer 4

• Supraoptic region (internal to optic chiasm)
• Tuberal region (internal to tuber cinereum)
• Mammillary region (internal to mammillary bodies)

Question 5

What are the 4 nuclei in the supraoptic region?

Answer 5

• Supraoptic
• Paraventricular
• Suprachiasmatic
• Anterior

Question 6

Supraoptic and paraventricular nuclei contain _____ and _____ and transmit them to posterior pituitary via the supraopticohypophysial tract.

Answer 6

Oxytocin and ADH (vasopression)

Question 7

The suprachiasmatic nucleus is believed to regulate what?

Answer 7

Circadian rhythms (receives input from retina, communicates with other nuclei)

Question 8

The anterior nucleus is mostly involved in:

Answer 8

maintenance of body temperature

Question 9

What 3 nuclei are in the tuberal region?

Answer 9

• Ventromedial
• Dorsomedial
• Arcuate

Question 10

Bilateral lesion to the ventromedial nuclei leads to…

Answer 10

Continuous stimulation of hunger –> excessive eating (it’s a satiety center)

Question 11

Lesion to lateral hypothalamus results in…

Answer 11

Inadequate production of feeding signal –> anorexia

Question 12

Stimulation of dorsomedial nucleus of the thalamus leads to…

Answer 12

Unusually aggressive behavior, lasting during stimulation. Sham Rage.

Question 13

The arcuate nucleus is the primary location for ________

Answer 13

neurons with releasing hormones. Transmitted to anterior pituitary via tuberoinfundibular tract and hypophysial portal system

Question 14

What 4 nuclei are in the mammillary region?

Answer 14

• Medial mammillary
• Intermediate mammillary
• Lateral mammillary
• Posterior hypothalamic

Question 15

Lesion of the mammillary body causes:

Answer 15

failure of retention of newly acquired memory, so that an immediate memory or a short-term memory is not processed into long-term memory (anterograde amnesia); hard to learn new tasks

Question 16

What is Korsakoff Syndrome?

Answer 16

Caused by thiamine deficiency (associated with chronic alcoholism) –> progressive degeneration of mammillary bodies and related structures (hippocampus, MD thalamus)

Question 17

What are some characteristics of Korsakoff Syndrome?

Answer 17

Difficulty understanding written material, conducting conversation due to forgetting what the just said, and confabulating memories to a synthesized memory that never occurred

Question 18

The posterior hypothalamic nucleus is associated with _______

Answer 18

The PAG and has associated emotional, cardiovascular, and analgesic functions

Question 19

The periventricular zone nuclei function similarly to the ______

Answer 19

Arcuate nuclei

Question 20

What hormones cause a decrease in feeding? What is this stimulated by?

Answer 20

• TSH and ACTH

- leptin

Question 21

Horner syndrome can ALSO be caused by:

Answer 21

Lesion to hypothalamomedullary fibers

Question 22

What can cause diabetes insipidus?

Answer 22

Lesion to supraoptic, paraventricular nuclei, supraopticohypophysial tract, pituitary damage from tumor, shearing of pituitary stalk in head trauma

Question 23

What is diabetes insipidus?

Answer 23

Deficiency of ADH, leading to polyuria, polydipsia, dilute urine (ethanol contributes to ADH deficiency)

Treatment: Synthetic vasopressin

Question 24

ADH secreting tumor causes:

Answer 24

Hyponatremia

Question 25

What is gigantism?

Answer 25

Excessive GH production before closure of growth plate --> bone overgrowth and large but weak muscles (excessive connective tissue)

Question 26

What is acromegaly?

Answer 26

Overproduction of GH after closure of growth plate --> elongated face, malocclusion of jaw, sinus bulges, thickened lips, large hands/feet...excessive cortical thickening of bone, cardiomegaly, hypertension, diabetes mellitus

Question 27

What is hyperthyroidism?

Answer 27

Overproduction of TSH --> increased T3/T4 in blood, causing nervousness, sweating, insomnia, tremor, weight loss, heat sensitivity, abnormal cardiovascular function, and cranial nerve signs (VI, then III and IV)

Question 28

What is Cushing Disease?

Answer 28

Overproduction of ACTH (hyperadrenalism) --> Truncal obesity, violaceous striae (purple streaks), easy bruising, hypertension, facial hirsutism, moon-face, cervicodorsal fat pad

Question 29

What causes insomnia?

Answer 29

Lesion to ventrolateral preoptic nucleus (VLPO) --> inability to inhibit tuberomammillary nucleus --> constant histamine production

Question 30

What is narcolepsy?

Answer 30

Lesion to orexin neurons (lateral hypothalamic area) --> inability to stimulate tuberomammillary nucleus --> inadequate histamine release --> sudden, uncontrolled sleep

Question 31

Adenomas in the pituitary can compress hypothalamic structures, leading to ______

Answer 31

functional deficits...

Question 32

List some secreting pituitary tumors (most common one first):

Answer 32

Prolactin, GH, TSH, ACTH, LH, FSH

Question 33

Non-secreting pituitary tumors/adenomas can cause:

Answer 33

Visual disturbances and headaches

Question 34

Caudolateral hypothalamus lesion causes:

Answer 34

Inhibition of sympathetic activity and reduction in body temperature

Question 35

Rostromedial hypothalamus lesion causes:

Answer 35

Inhibition of parasympathetic activity and increase in body temperature

Question 36

What does a prolactin-secreting tumor cause?

Answer 36

- Galactorrhea (milk production) | - Amenorrhea (no menstruation)

Question 37

How does the temperature regulation reflex work for rising temperature?

Answer 37

Blood reaches hypothalamus is warmer --> stimulate rostral hypothalamus --> heat dissipation mechanisms are activated (sweating, cutaneous vasodilation, ANS)

Question 38

How does the temperature regulation reflex work for falling temperature?

Answer 38

Blood reaches hypothalamus is cooler --> stimulate caudal hypothalamus --> heat conversion mechanisms are activated (cutaneous vasoconstriction, ANS) and heat production (shivering, reticulospinal pathway)

Question 39

What is the water balance reflex?

Answer 39

Osmolarity of blood sensed via neurons in anterior hypothalamus (near preoptic and PVN) --> ADH released from supraoptic nucleus and paraventricular nucleus

Question 40

What is the rostral boundary of the hypothalamus?

Answer 40

Lamina terminalis (and anterior part of 3rd ventricle)

Question 41

What is the superior boundary of the hypothalamus?

Answer 41

Hypothalamic sulcus

Question 42

What is the lateral boundary of the hypothalamus?

Answer 42

Substantia innominata and posterior limb of internal capsule

Question 43

What is the medial boundary of the hypothalamus?

Answer 43

Inferior part of 3rd ventricle

Question 44

What is the caudal boundary of the hypothalamus?

Answer 44

Merges into midbrain tegmentum and PAG (externally, the mammillary body)

Question 45

Where does the posterior pituitary (pars nervosa) come from?

Answer 45

Outpocketing of diencephalon

Question 46

Where does the anterior pituitary (adenohypophysis) come from?

Answer 46

Rathke pouch (also, pars tuberalis and pars intermedia)