6.4.3 Hypothalamus Flashcards
What is the difference between leptins and Ghrelins?
- Leptins: produced in adipose tissue and reduce appetite
- Ghrelins: Produced in gastric mucosa stimulate appetite
How can the hypothalamus change the body temperature set point (fever)?
Hypothalamic neurons activated (pre-optic)
-Activation of septum can reduce fever
How is temperature info conveyed to the hypothalamus? Which nucleus of the hypothalamus senses temperature
Somatosensory system - temperature sensitive afferents
neurons in anterior nucleus of hypothalamus sense temp
What are the two main systems that the hypothalamus uses to carry out endocrine functions?
Neurohypophyseal and Tuberoinfundibular
What nucleus in the hypothalamus plays a role in descending control of preganglionic PARA and SYM neurons
Paraventricular nucleus
How does the hypothalamus play a role in the circadian rhythm?
Suprachiasmatic nucleus; input from retinal ganglion cells containing melanopsin; project to SCN at chiasm
Regulates core body temp; ACTH levels, slow wave sleep; skin temp
What are the four functions of the limbic system?
Homeostasis
Olfaction
Memory
Emotions and Drives
Where do the neurohypophyseal system and tuberoinfundibular system project? What endocrine functions are mediated by these systems?
What are the afferent inputs into the hypothalamus?
Retina - SCN for circadian function
Fornix - from hippcampus
Amygdala - autonomic component
Medial forebrain bundle
What are the functions of the hypothalamus?
Homeostasis
Endocrine
Autonomic
Limbic
Which regions of the hypothalamus play a role in feeding behavior? What are their effects?
Ventromedial nucleus - satiety stimulation (stimulation reduces food intake, lesions produce overeating and obesity)
Lateral nuclei - feeding center (stimulation produces eating, lesion produce anorexia)
Identify these anatomical landmarks for the hypothalamus
How does the hypothalamus control thirst/body fluid?
ADH (vasopressin) release by supraoptic nucleus
anterior nucleus involved in coordinating drinking behavior
What are the efferent connections of the hypothalamus?
Decending autonomic control - from paraventricular nucleus
Mamillothalamic tract - papez circuit, to anterior n. thalamus
Reciprocal connections
Which parts of the hypothalamus coordinated the body’s response to changes in temperature? Warm or cold?
Response to warm: Anterior nucleus
Response to cold: Posterior nucleus
