Hypothalamus Satiety Center
Ventral Medial Hypothalamus
Hypothalamus Feeding Center
Signals that Stimulate feeding
Appetite in Greek
Neuropeptide Y (NPY) function
Increases food intake and decreases energy use.
Agouti Related Peptide (AGRP) Function
Increases food intake and decreases energy use. Tends to be excessive in some obese people.
Corticotrophin Releasing Hormone (CRH)
Decreases food intake and increase energy expenditure, increase sympathetic nervous activity.
Decreases food intake and increases energy expenditure, increases SNS. Mutation of these receptors are considered the most common monogenetic cause of obesity in humans and are found in 5-6% of early onset (childhood) severe obesity.
is one hell of a drug. Decrease appetite.
Amphetamine Regulated Transcript (CART)
Amygdala stimulation or destruction
Can increase or decreases feeding - alters input to the hypothalamus.
Which Nerve delivers impulses to the amygdala first?
If both sides of amygdala is damaged...
Person will have no preference in type of food that they eat.
Increased glucose and Insulin levels act on?
Insulin dependent glucose receptors in both the Satiety and Feeding centers to sense level of satiety
Insulin alone causes?
Hunger. Thoughts or Smell or even tasting something sweet (Aspartame/Stevia/Saccharine/etc.) will cause insulin release and thus lower blood glucose levels making the person have a real need for glucose.
Increased Cortisol secretion thus increased appetite
elevated glucose in the absence of insulin or lack of insulin sensitivity
Produced when fasting. Makes you hungry.
Peptide YY (PYY)
Produced by the entire digestive tract in response to food intake - highest in fatty meal. Decreased food intake for several hours.
Increased energy expenditure effect on appetite over long period.
Will increase appetite for up to 3 days after.
Increase food intake without physical exertion.
Decrease in appetite over the next few days. Makes sense.
Metabolic changes with age? (Enzyme)
Decreased activity of Lipase which causes weight gain with aging. Can be minimized or stopped with regular exercise.
Exercise increases can increase which two metabolic hormones?
Growth Hormone and Epinephrine, both of which stimulate lipolysis.
Cold Temperature increase this hormone?
Thyroxine, which increases appetite. Crave fatty foods --> weight gain and increased thermiogenesis (Increased metabolic rate to increase heat production)
Warm Temperatures decrease this
Thyroxine, which decreases appetite and weight loss.
Hormones produced by Adipose cells
adipokines. Secreted in response to total body fat.
When body fat is decreasing what is Stim/inhibited?
Appetite increase and inhibited metabolic rate.
When body fat is increasing what is Stim/Inhibited?
Appetite is inhibited and metabolic rate is stimulated
Leptin is secreted or inhibited when?
Stimulated by increased fat stores and inhibited with short term fasting or weight loss.
Leptin has these metabolic effects (9 listed)
Inhibit Appetite, Insulin and Glucose Levels in blood. Decreases Body fat. Increases Metabolic rate, temperature, physical activity, and fatty acid acid oxidation. Activates the Immune System.
Leptin acts on the Hypothalamus to increase these 3 chemicals to do this.
The production and release of CRH (Corticotrophin Releasing Hormone), CART (Amphetamine Regulated Transcript), and Melanocortin to decrease appetite and increase metabolic rate.
Decrease or absence of Leptin or lack of response causes this to be released and it has this effect.
Neuropeptide Y which increases appetite and decreases metabolic rate.
Congenital Leptin problems cause
Fat Babies. The kids have a strong appetite and gain weight rapidly. Behavioral problems from a restricted diet. Leptin treatment will alleviate these symptoms. This is why we don't put shlt in our bodies before OR during pregnancy. Who wants fat kids?
Reduces body weight and fat in rodents, increases thermiogenesis (heat production)
Increases Insulin sensitivity, suppresses gluconeogenesis, stimulates fatty acid oxidation and has anti-inflammatory and anti-arthrogenic actions.
Produced by adipocytes and immune cells. It RESISTS Insulin. This can cause Diabetes Mellitus II, it inhibits adipogenesis, increases GNG. Production is increased with obesity and decreased with even minimal weight loss. Can recover Insulin sensitivity and DM II.
Amylin - What is it?
A hormone produced by Pancreatic Beta cells (same guys that make insulin) and is secreted with insulin.
Amylin - What's it do?
It acts on hypothalamic neurons to produce satiety.
Acts on Vagus to decrease rate of gastric emptying.
Decreases Glucagon secretion which means less glucose is released from liver and less glucose absorption from GI.
An analog to Amylin that is used to help control blood glucose of DM I and II
Also enhances the affect of Leptin.
The act of eating oneself. For our purpose it's neurons during starvation or at least, the body's perception of starvation.
Ventilation (respiration) accomplishes two things.
Oxygenating the blood, and removing CO2 from the blood
CO2 released into the blood from cell respiration is converted to what?
Carbonic Acid when combined with water.
The enzyme the combines CO2 and Water is?
The Carbonic Acid formed in the RBC dissociates to form what?
Bicarbonate Anion and H+ Cation
After leaving the RBC where does Bicarbonate and H+ diffuse too?
Into the plasma and the H+ bonds to hemoglobin within an RBC.
What moves into the RBC to buffer HCO3- coming out?
Chloride. This is called the Chloride Shift.
Upon Expiration what happens to Bicarbonate and H+?
Bicarbonate and H+ combine forming H2O and CO2. Cl- goes back into the plasma.
What is the most important buffer in the blood?
At what blood pH are you in acidosis?
At what blood pH are you in alkalosis?
Which are the 3 main pH chemoreceptors in the body?
Arch of Aorta, Carotid Body, and Medulla Oblongata.
What is the Hering-Breuer Reflex?
When inhalation continues to a point that stretch receptors in the pulmonary walls cause inhibition of the respiratory center, thus causing the respiratory muscles to chill.
Why do people get dizzy during hyperventilation?
CO2 is a vasoconstrictor that acts on the vasomotor center of the brain, therefore when CO2 gets low, general vasodilation occurs which then drops the blood pressure lowering brain blood.
The Dorsal Respiratory group are what kind of neurons?
Nucleus Tractus Solitarius is part of what group and receives what kind of input and from what nerves
The Nucleus tractus solitarius recieves sensory input from chemoreceptors of the medulla oblongata, aortic and carotid bodies and stretch receptors from the lungs, all via the vagal and glossopharyngeal afferents.
If you activate the Dorsal Respiratory group you will stimulate what action? Via what muscle? That is controlled by which nerve
Inhalation by stimulating the diaphragm through the phrenic nerve.
Ventral Respiratory group has which type of neurons?
Both Inspiratory efferent neurons (central region) and expiratory efferent neurons (on either side)....You Breathe air in starting from your mouth/nose (central) and breathe out starting from your lungs (laterally).
The ventral respiratory group of neurons stimulates which groups of muscles?
Activated during increased need for respiration. Activates expiratory muscles and accessory inspiratory muscles. Does not get stimulated during quiet breathing.
Medullary Chemosensory cells do what?
measure pH of cerebrospinal fluid and influence DRG neurons.
Which acids affect the pH of CSF?
H+ only, Fatty acids, Amino Acids, Lactic Acid, etc. DO NOT cross the blood brain barrier.
What are the H+ CSF pH limits?
<5% Stop Breathing
>5% Increased breathing
(H+ = High Fives for everyone!)
Can breathing fix metabolic acidosis?
No. Peeing can.
The Carotid Bodies and Aortic Arch detect changes in pH. Which is the strongest influencing factor? What kind of nerves can they recieve?
Blood CO2 is the strongest factor in chemosensation. They recieve efferent impulses from both Para and sympathetic NS's. They send feedback to the DRG.
Apneustic Center is found where and does what?
Found in the lower pons and basically sends excititory information to the DRG to set the rhythm for breathing (the DRG bases its rhythm off of chemosensory input, which is irregular). The Apneustic center also recieves input from the Reticular Activating System on the brainstem and provides information to the Pneumotaxic center.
Apneustic breathing is what?
20-30 seconds of inspiration followed by gasping exhalation due to lack of input from the Pneumotaxic center.
Pneumotaxic center is found where, and does what?
Upper Pons, it inhibits the apneustic center.
What is the oscillatory (rhythmic) circuit of respiration?
The Apneustic center turns on the Pneumotaxic center and also in reverse where the Pneumotaxic center turns off Apneustic center. This provides quiet breathing with a simple 2 seconds inhale and 3 seconds exhale.
Increased Pneumotaxic center activity will cause what?
Fast shallow breaths (30-40/min). Shortens the duration of the DRG ramp
Somatic Motor Cortex is used for what?
Voluntary changes in respiration. If held too long then the person will faint and the their automatic breathing systems will continue.
What kind of fat secretes Tumor Necrosis Factor Alpha?
Which type of fat breaks down more quickly?
Visceral fat, bitch.
How does Dark Chocolate help with artherosclerosis?
Makes platelets less likely to stick together.