Exam 3 Material (Internal Regulation Lecture) Flashcards
What is the energy used to maintain a constant body temperature at rest?
Basal metabolism
What are regulation processes that keep certain body variables within a fixed range or at a set point (single value the body works to maintain/similar to a thermostat)?
Homeostasis
What is one of the body’s top biological priorities (uses about two-thirds of our energy per day)?
Temperature regulation
What is an adaptive change in a set point in response to changes in life or the environment (e.g., weight gain in fall, loss in spring/fever)?
Allostasis
What type of species have body temperatures that match the environmental temperature (amphibians, reptiles, and most fish/AKA “cold-blooded/ lack physiological mechanism for temperature regulation)?
Poikilothermic
What is accomplished by choosing locations in the environment (e.g., snake in sun)/used exclusively for temperature regulation in poikilothermic animals/also used in other animals?
Behavioral regulation
What is the use of internal physiological mechanisms to maintain an almost constant body temperature (e.g., 98 degrees)/characteristic of mammals and birds/ requires energy and fuel/warm-blooded animals?
Homeothermic
What happens when the body is hot (parasympathetic)?
Sweating and panting
What happens when the body is cold (sympathetic)?
Shivering, increasing metabolic rate, decreasing blood flow to the skin, etc. increase temperature
What area of the brain controls body temperature?
Preoptic area/anterior hypothalamus (POA/AH)
What monitors the body’s temperature by monitoring its own temperature?
POA/AH
Heating the POA/AH leads to what?
Panting or sweating
Cooling the POA/AH leads to what?
Shivering
What increases the body’s set point (the immune system response activates the vagus nerve-stimulating the hypothalamus to initiate this/behavioral regulation ineffective in reducing this)?
Fever
What is good about a fever?
Some bacteria grow less vigorously in warmer than normal body temperature/fever enhances activity of the immune system
What is bad about a fever?
A fever above 103 degrees does the body more harm than good/fevers above 109 degrees are life-threatening
What is water conserved by?
Concentration of urine/decreasing sweat and other automatic responses
How is water regulation accomplished?
Drinking more water than we need and excreting the rest
What are the two types of thirst?
Osmotic thirst and hypovolemic thirst (each kind of thirst motivates different behaviors)
What is a thirst resulting from eating salty foods?
Osmotic thirst (you crave pure water)
What is a thirst resulting from loss of fluids due to bleeding or sweating?
Hypovolemic thirst (you crave slightly salty water)
What type of thirst helps the body maintain a concentration of solutes at a fixed level?
Osmotic thirst
What is a hormone released by the posterior pituitary (constricts blood vessels-raises blood pressure/kidneys reabsorb water, concentrated urine/Compensates for the decreased water volume)?
Vasopressin
What area of the brain is part of the hypothalamus, CONTROLS DRINKING (initiates thirst), receptors in the stomach provide feedback to inhibit drinking/thirst?
Lateral preoptic area
What does the body do to inhibit thirst?
- Monitors swallowing
2. Detects the water contents of the stomach and small intestine
What type of thirst is associated with low volume of body fluids (AKA volumetric thirst), triggered by vasopressin and angiotensin II (hormones), constrict blood vessels to compensate for a drop in blood pressure?
Hypovolemic thirst
What is a strong craving for salty foods (develops automatically to restore solute levels in the blood)?
Sodium-specific hunger
Where do enzymes digest proteins, fats, and carbohydrates/ digested food absorbed into bloodstream?
Small intestine
What absorbs water and minerals/passes waste?
Large intestine
What experiment had a tube connected to the stomach prevents it from filling (no satiety, mouth sensations not sufficient for satiety)?
Sham feeding experiments
What conveys information about the stretching of the stomach walls to the brain?
Vagus nerve
What conveys information about the nutrient contents of the stomach?
Splanchnic nerves
What part of the small intestine is where the initial absorption of nutrients occurs (distention of this produces feelings of satiety)?
Duodenum
What hormone does the duodenum release?
Cholecystokinin (CCK)
How does cholecystokinin (CCK) regulate hunger?
- Closing the muscle between the stomach and duodenum (the stomach holds its contents and fills faster)
- Stimulating the vagus nerve to send a message to the hypothalamus to signal satiety
What levels influence feelings of hunger?
Glucose, insulin, and glucagon
What is a pancreatic hormone that enables glucose to enter the cell?
Insulin
When do insulin levels rise?
As someone is getting ready for a meal and after a meal
When is the pancreatic hormone glucagon released?
When glucose levels fall
What stimulates the liver to convert some of its stored glycogen to glucose to replenish low supplies in the blood?
Glucagon
What do the body’s fat cells produce (low levels increase hunger, high levels decrease hunger, increase physical and immune activity)?
The peptide leptin
Obesity caused by consistent overeating damages the neurons of what structure (leads to decreased leptin sensitivity)?
Hypothalamus
Where do hunger signals converge onto (contains neurons sensitive to hunger signals/neurons sensitive to satiety signals)?
Arcuate nucleus in the hypothalamus
Neurons of the arcuate nucleus specifically sensitive to hunger signals receive input from where?
Taste pathways/the neurotransmitter ghrelin
What is released as a neurotransmitter in the brain and as a hormone in the stomach (released from stomach during food shortages/in the stomach also trigger contractions, binding in the arcuate signals hunger)?
Ghrelin
What limits food intake?
Melanocortin
Lateral hypothalamus releases orexin, which does what?
- Increases animals’ peristence in seeking food
2. Responds to incentives and reinforcement
What is responsible for these actions?:
- Acts in the NTS to make food taste better
- Facilitates ingestion, swallowing, and responsiveness to taste, smell, and sight of food
- Increases insulin secretion
- Increases digestive secretions
Lateral hypothalamus
Damage to what structure leads to overeating and weight gain (stomach to empties faster than usual)?
Ventromedial hypothalamus
What does the paraventricular nucleus inhibit (important for feelings of hunger)?
Lateral hypothalamus
The paraventricular nucelus releases what (limits food intake)?
Melanocortin
Input from the hunger-sensitive neurons of the arcuate nucleus is inhibitory to both the what?
Paraventricular nucleus and the satiety-sensitive cells of the arcuate nucleus itself
Arcuate nucleus projects to the what in the hypothalamus?
Paraventricular nucleus
Satiety-sensitive cells of the arcuate nucleus deliver an excitatory message to the what?
Paraventricular nucleus
Input to the satiety-sensitive cells of the what include:
- Short-term satiety signals (distention of the intestine triggers neurons to release the neurotransmitter CCK/blood glucose and body fat increase blood levels of the hormone insulin and related peptides)
- Long-term satiety signals (leptin provides additional input)
Arcuate nucleus
