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Flashcards in 57 Homeostatic control by the CNS Deck (18)
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1
Q

Which of the following are specific functions of the hypothalamus?

A. control endocrine functions, e.g. reproductive functions
B. control autonomic functions like emergency response to stress
C. control circadian cycle
D. control energy metabolism
E. control blood pressure
F. regulate body tempature

A

All of the above
D: feeding behaviour
C: sleep wake cycle

2
Q

What are the major inputs to the hypothalamus?

A
  1. brainstem/ spinal cord
  2. amygdala (limbic areas), hippocampus
  3. cortex
  4. eyes
3
Q

What are the major outputs of the hypothalamus? What control are they involved in?

A
  1. Brainstem, spinal cord (autonomic control)
  2. Limbic system: hippocampus/ amygdala (motivational control)
  3. Cortex (motivational control)
  4. Pituitary gland (neuroendocrine control)
4
Q

How can the hypothalamus access to blood composition?

A
  1. Via circumventricular organs (subfornical organ,…) where the BBB are porous
  2. via the pituitary gland to control endocrine functions
5
Q

______________ neurons in different hypothalamic nuclei (arcuate, paraventricular etc.) release different hypothalamic factors that reach capillary beds in the anterior pituitary

A

Parvocellular

6
Q

Magnocellular neurons release _____________ and _____________ into _________ pituitary.

A

Oxytocin and vasopressin; posterior

7
Q

Oxytocin and vasopressin are produced by the magnocelluplar neurons in the _____________ and ___________ nucleus.

A

supraoptic nucleus; paraventricular nucleus

8
Q

Main functions fo oxytocin and vasopressin?

A

Oxytocin: uterine contraction, lactation;
Vasopressin: antidiuretic hormone

9
Q

Briefly describe the endocrine response to stress.

A

Periventricular hypothalamus secretes CRH into hypopituitary circulation > triggers ACTH release into circulation.
ACTH stimulates release of cortisol from the adrenal cortex > increase energy resources and immunosuppression etc.

10
Q

In stress under emergency situation, activation of sympathetic/parasympathetic and release of ___________ from the adrenal _________; resulting in pupil dilation, increased pulmonary ventilation, glycogenolysis, increase in blood glucose level.

A

sympathetic;

adrenaline; medulla

11
Q

After receiving sensory information from the entire body, the hypothalamus compares the sensory information with ________________ such as ________________.

A

Biological set points;

temperature, plasma volume/osmolarity, fat reserve

12
Q

When detected a deviation from the set point, the hypothalamus adjusts ___________, __________ and ___________ responses to restore homeostasis.

A

Endocrine; autonomic, behavioural

13
Q

The ob gene and its project, _______, is a critical factor controlling feeding behavior, and therefore body fat reserve.

A

leptin

14
Q

Describe the events happen when body fat reserve increases.

A

When body fat increases, [leptin] increases, detected by leptin receptors in the arcuate nucleus expressing MSH + CART.

  1. Hormonal: stimulate release of ACTH and TSH from the pituitary > increase metabolic rate
  2. Autonomic: activate sympathetic preganglionic neurons > increase sympathetic activity
  3. Behavioral: inhibit lateral hypothalamic area > inhibit feeding behaviour
15
Q

Leptin is a hormone released by ____________ to induce ___________. Mutation of the leptin gene is a cause of rare rely onset __________.

A

Fat cells in adipose tissue;
reduced food intake;
obesity

16
Q

What is the lateral hypothalamic area for? What will happen if there is a lesion?

A

For initiating feeding, hunger center;

lesioned > anorexia (lateral hypothalamic syndrome)

17
Q

What is the ventromedial hypothalamic area for? What will happen if there is a lesion?

A

satiety center;
lesioned > obesity

(paraventricular nucleus involved in feeding)

18
Q

Describe sequence of events when there is a decrease in body fat reserve in the body.

A

Decrease body fat > [leptin] decreases > decrease of leptin inhibition on a group of NPY + AgRP-expressing arcuate nucleus neurons.

NPY (Neuropeptide Y) and AgRP are orogenic (appetite promoting)

  1. Hormonal response: inhibit ACTH and TSH, decrease metabolic rate
  2. Autonomic: activate brainstem and spinal preganglionic neurons, increase parasympathetic activity
  3. Behavioural: stimulate lateral hypothalamic area > stimulate feeding