Chapter 15 The Hypothalamus and Regulation of Bodily Functions

Question 1

Function of the Hypothalamus

Answer 1

-Crucial for maintaining organ function and producing many of the behaviors necessary to meet basic needs such as feeding, drinking, mating, and sleeping

Question 2

Hypothalamic sulcus

Answer 2

-Separates the hypothalamus form the thalamus
(3rd ventricle separates two halves of hypothalamus)

Question 3

Where is the Hypothalamus in relation to the thalamus?

Answer 3

-Located ventral and anterior to the thalamus

Question 4

Hypothalamus extends anteriorly and caudally to beyond what?

Answer 4

-Anteriorly: 3rd ventricle
-Caudally: mammillary bodies

Question 5

Periventricular zone

Answer 5

-Most medial, thin layer that borders 3rd ventricle
-Regulates release of endocrine hormones from anterior pituitary gland

Question 6

Middle Zone

Answer 6

-Between periventricular and lateral
-Regulates release of endocrine hormones from the posterior pituitary gland
-Site that regulates neurons of autonomic nervous system
-Body’s biological clock, control of wakefulness

Question 7

Lateral Zone

Answer 7

-Separated from middle zone by the fornix
-Contains neurons that integrate info from other hypothalamic nuclei structures engaged in emotion
-Regulating sleep, wakefulness, feeding
(C shaped tract interconnects limbic system structures)

Question 8

Innervation of visceral organs

Answer 8

-Autonomic

Question 9

What are the two neurons that link the CNS with organs in the periphery?

Answer 9

-Preganglionic neuron
-Postganglionic neuron

Question 10

What is Visceral control mediated by?

Answer 10

-Ipsilateral hypothalamus
-Brain stem nuclei

Question 11

Which way does the circuit descend?

Answer 11

-Laterally (ipsilaterally) through the hypothalamus in the medial forebrain bundle
-Axons leave bundle running in the dorsolateral tegmentum in brainstem
-Synapses on brainstem parasympathetic nuclei (vagus) and spinal sympathetic/parasympathetic neurons in spinal cord

Question 12

Organization of Autonomic Nervous System

Answer 12

Sympathetic:
-Preganglionic found in intermediate zone
-Postganglionic found in ganglia near spinal cord
Parasympathetic:
-Preganglionic found in brainstem and sacral spinal cord segments
-Postganglionic found in ganglia near or on organ

Question 13

Suprachiasmatic nucleus

Answer 13

-Above optic chiasm
-Function as brain’s “clock”
-Pineal gland releases melatonin

Question 14

Preoptic area (POA) sleep center

Answer 14

-Functions in switching from wakefulness to sleep
-Many neurons are GABAergic (inhibit brainstem neurons that maintain arousal)
-Tuberomammillary nucleus uses histamine as its neurotransmitter

Question 15

REM Sleep

Answer 15

-lateral hypothalamus
-Most dreams during this
-Muscle atonia, high level of forebrain arousal