Hypothalamus and Feeding Flashcards
What are the three hypothalamic responses to maintain body homeostasis (with general descriptions)?
The humoral response (hormonal modulation)
The viscero-motor response (ANS sympathetic and parasympathetic systems)
Somatic motor response (Move appropriate somatic motor behaviour)
What cells secrete vasopressin? What behaviour does this motivate?
Magnocellular cells of the peri-ventricular posterior hypothalamus control drinking signals
What hormones are secreted by the anterior pituitary gland and what behaviours do they motivate?
TSH and ACTH control eating signals and Thermal signals
How does the brain signal feeding? What is the visceromotor response?
Leptin and Insulin lower, which lowers ACTH and TSH, which increase parasympathetic activity and hunger
What hormone is associated with thermal change?
TSH
What is the relationship between temperature and TSH release? What are the visceromotor responses?
They are inverse, low temp increases TSH (sympathetic activity) and high temp decreases TSH (increase in parasympathetic activity)
What are the two brain signals to promote drinking?
Higher angiotensin 2 and higher blood tonicity
What kind of ANS activity does the expression of vasopressin lead to?
Sympathetic nervous activity
What is the feeding behaviour cycle as a holistic brain approach?
- Attention is given to the stimulus
- The prefrontal cortex demonstrates cognitive control to process the information
- The amygdala/hippocampus evokes emotion/memory about the information
- The hypothalamus maintains homeostasis and takes into account the state of the body
- The reward system is linked to motivating feeding
What is the difference between the anabolic and catabolic metabolism states?
Anabolic - prandial state - nutrients in the blood go to cells and storage
Catabolic - postabsorptive state - nutrients go from storage to cells
Where are nutrients stored in the body and what is the most efficient nutrient storage pathway?
It is stored in the liver, skeletal muscle, and adipose tissue is the most efficient storage.
What is the role of glycogen in the metabolism system?
It is the storage form of glucose, which is important for cell activity and is the most important neuronal fuel
What nutrients are present in the blood from food?
Glucose, fatty acid, and ketones
What is stored glucose called in adipose tissue?
triglycerides
When is stored fat in the body bad?
When there is an excess that is not stored where it is supposed to be, and is stored around organs like the liver or heart
What is the lipostatic hypothesis?
The brain monitors adipose tissue and acts to maintain an adequate amount
How is adipose regulated in the long run and short run?
Short run - meal size/frequency
Long run - lipostatic hypothesis (fat reserve maintenance)
What is the estimated heritability rate of body weight/obesity?
0.7-0.8
Are twins or people that grew up together more likely to share the same level of obeisity?
Twins
How did Coleman determine the effect of molecules on feeding?
Parabiosis of mice (WT, db, ob)
What was Friedman’s role on leptin research?
He cloned the leptin gene
What was the finding/conclusions of the parabiosis of a WT mouse and a ob mouse?
Ob mouse reached a normal weight indicating there was something in the blood of the WT mouse that reduced feeding
What was the finding/conclusions of the parabiosis of a WT mouse and a db mouse?
WT mouse died of starvation, indicating elevated blood presence of leptin (high satiety)
What is the physiological difference that Coleman found between the db and ob mice?
Db mice: missing leptin receptor leading to high level of leptin in the blood
Ob mice: missing leptin - always hungry
