Physiology Hypothalamus

Front 1

What is the hypothalamus, and what are its most important features?

Back 1

The hypothalamus is an organ that:

1)Connects the endocrine system with the nervous system

2)Major component of the limbic system and acts as an output pathway.

Front 2

The hypothalamus helps control 5 important body functions, what are they?

Back 2

1)Controls blood pressure and electrolytes(Drinking(Thirst center) and salt appetite)

2)Regulates body temperature

3)Regulates energy metabolisim(By eating, digestion, appetite etc)

4)Regulates reproductive functions

5)Regulates response to stress by regulating the function of the adrenal glands.

Front 3

-BP,BT,RES

Front 4

What is the cyclic phenomena, and whats another name given for it?

Back 4

Circadian rhythm, it is the rhythm of the body that is controlled 24 hours and it includes:

1)Secrtion of hormones (ACTH, pineal hormone melatonin)

2)Sleep-wake cycle

3)Activity patterns

4)Body temperature rhythms

Front 5

What is the primary pace maker for the cyclic phenomena(Circadian rhythm)?

Back 5

Suprachiasmatic nucleas of the hypothalamus.

Front 6

How does the hypothalamus control emotions?

Back 6

The hypothalamus is responsible for the control of 2 important emotions,

1)Rage centers

2)Placidity centers

Front 7

Most human beings maintain normal homeostasis by a balance between placidity and rage.

Back 7

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Front 8

Where are rage centers?

Back 8

Rage centers are centers found in the lateral hypothalamic nucleas.

Front 9

What stimulates rage centers, and what inhibits it?

Back 9

Stimulated by: Amygdaloid nucleus and limbic system

Inhibited by: Neocortex and placidity center (Ventromedial hypothalamic nuclease.

Front 10

Where is the placidity center found?

Back 10

It is found in Ventromedial hypothalamic nucleas.

Front 11

What causes abnormal placidity?

Back 11

Bilateral destruction of Amglydoid nucleus.

Front 12

What happens if it was followed by subsequent destruction of the ventromedial hypothalamic nucleus?

Back 12

Rage.

Front 13

What causes extreme rage (Rage and sham reaction)?

Back 13

Destruction of the Ventromedial hypothalamic nucleus.

Destruction of the neocortex

Stimulation of the Amglydoid nucleas

Front 14

Discuss lesions of rage centers

Back 14

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Front 15

How does the hypothalamus control temperature?

Back 15

In the hypothalamus, we have 2 nuclei,

Anterior nuclei: For heat loss

Posterior nuclei: For heat gain

Front 16

What stimuates the anterior nuclei?

Back 16

The anterior nuclei (Heat loss) is stimulated by heat. It then causes heat loss by vasodilation and sweating. It release norepinphren

Front 17

What happens if there was a lesion in the anterior hypothalamic nucleus?

Back 17

Hyperthermia

Front 18

What stimulates the posterior nuclei?

Back 18

Posterior nuclei (Heat gain) is stimulated by cold.

It then causes shivering to lose heat. The neurotransmiiter is serotonin.

Front 19

What happens if there was a lesion in the posterior nuclei?

Back 19

There would be no heat gain, Hypothermia

Front 20

Exposure to hot temperature leads to?

Back 20

Activation of the posterior hypothalmic nuclei

Front 21

Exposure to cold temperature leads to?

Back 21

Activation of the heat gain, Posterior nuclei.

Front 22

Mechanisim of fever?

Back 22

The cytokines produced by bacteria resets the anterior (Preoptic nuclei of the hypothalamus) and causes increase in temperature

Front 23

What is the preoptic hypothalmic nuclei?

Back 23

The anterior nucleus of the hypothalamus.

Front 24

How does the hypothalamus affect food intake?

Back 24

We have 2 food centers in the hypothalamus

1)Feeding center

2)Satiety center

Front 25

Where is the feeding center found?

Back 25

In the lateral hypothalamic nucleus

Front 26

Where is the Satiety center found?

Back 26

In the Ventromedial nucleus

Front 27

What happens if we stimulate the feeding center?

Back 27

Feeding: Hunger

Satiety: Cessation of food

Front 28

What happens if there was a lesion in the Ventromedial nucleus(Satiety center)

Back 28

Leads to hypothalmic obesity, or hyperphagia.

Front 29

What are the 4 afferent hypothesis of food centers?

Back 29

1)The lipostatic hypothesis: Release of leptin

2)The Glucostatic hypothesis: Release of glucose

3)The Thermostatic hypothesis: Increase temp.

4)Gut peptide hypothesis: Release of GIT hormon

Release of all those inhibits the feeding and activates satiety

Front 30

What is leptin?

Back 30

Leptin This hormone released from adipose tissue acts on thehypothalamus to decrease food intake and increase energyconsumption. It decreases the activity of neuropeptide Y neurons and increasesthe activity of POMC-secreting neurons.

Front 31

Effects of lesion in the hypothalamus?

Back 31

Endocrine disorders: diabetes insipidus

. Sleep disturbances.

Hyperthermia or hypothermia.

Hyperphagia or anorexia.

Autonomic disturbances: sweating, VD or VC. Placidity or rage.

Obesity.

Sexual disturbances.

Front 32

Summary of lesions:

Back 32