ch 13 bio psych
Terms
undefined, object
copy deck
- aquaporins
- channels spanning cell membrane that conduct water molecules into/out of cell
- what 2 parts can the extracellular compartment of a cell be divided into?
- interstitial fluid (fluid between cells) and blood plasma
- what is the motive force behind osmosis?
- constant vibration and movement of the molecules
- adipsia
- refusal to drink
- what happens if the concentrations of molecules in body fluids is altered the smallest amount?
- basic cellular functions stop working properly and animal will die
- what is the basic thermoregulatory system made up of?
- receptors in skin, body core, hypothalamus detects/transmits info to 2 neural regions: spine, brainstem, hypothalamus
- hypertonic
- a solution with more salt than normal
- what are the 5 hormones involved in appetite?
- insulin, leptin, ghrelin, obestatin, PYY3-36
- diffusion
- tendency for molecules to move down the concentration gradient (from high concen. to low concen.)
- osmosis
- passive movement of molecules from one place to another
- what 3 categories can the behavioural thermoregulatory responses of ecto/endotherms be divided into?
- changing exposure of body surface, changing external insulation, selecting surroudings less thermally stressful
- hypotonic
- solution with less salt than normal
- ectotherms
- get most of their heat from the environment
- arcuate nucleus
- in hypothalamus which is implicated to appetite control
- set point
- the desired value of the system
- dehydration
- excessive loss of water
- osmosensory neuron
- measures the movment of water in/out of intracellular compartment
- what is the most efficient temp. for enzyme systems?
- 37 degrees celsius
- osmotic pressure
- force that pushes/pulls water across the membrane to equalize the concentration of a solute in a solution
- at what rate do animals lose heat?
- directly proportional to ratio of its surface area to its volume or weight (small animals lose heat faster so must eat more)
- what are the 2 key features of osmosensory neurons?
- they are stretchy; they use mechanically gated ion channels that open/close when cell is physically deformed
- what is adipose tissue formed from?
- fat used as long term storage
- what 3 sequential mechanisms stimulate insulin release? what are these stages called?
- sensory stimuli from food (cephalic phase), during digestion (digestive phase), when glucose enters bloodstream (absorptive phase)
- what are the 6 methods we have tried in order to gain control over obesity?
- appetite control, increased metabolism, inhibition of fat tissue, reduced absorption, reduced reward, anti-obesity surgery
- osmolality
- concetration of solute in a solution
- osmotic thirst
- desire to ingest fluids resulting from excessive loss of water from extracellular compartment; no volume change but high concentration of solute
- negative feedback
- some of the output system feeds back to reduce the effect of input signals
- what does a defect in leptin production cause?
- false underreporting of body fat causing animals to overeat
- what are the 2 different types of thermoregulation? where in the brain does this happen?
- behavioural regulation in lateral hypothalamus/ physiological regulation in preoptic area
- what are the 3 basic ways our body uses food for energy?
- basal metabolism, active behavioural processes, digestion of food
- what is a more conspicious way of generating heat?
- shivering; happens when body temp. drops below 36 degrees
- what is the pathway for information about glucose levels?
- liver via vagus nerve -->nucleus of the solitary tract in brainstem-->hypothalamus
- what hormones get released from hypovolemia? what do they do?
- vasopressin; contriction of blood vessels and renin; triggers formation of angiotensin 2
- endotherms
- generate most of their heat through internal processes
- what do lesions in the ventromedial hypothalamus cause?
- obesity in rats
- what happens if ghrelin is unresponsive to feeding?
- promts continual hunger
- kilocalorie
- measure of energy commonly applied to food (quantity of heat require to raise the temp by 1 degree)
- what is the rate of chemical reactions dependant one?
- temperature
- homeostatic
- active process of maintaining a particular physiological parameter relavtively constant
- trophic factor
- substance promoting cell growth and survival
- through what process do endotherms generate their heat?
- through the breakdown of food aka metabolism
- Maudsley therapy
- parent-led refeeding of an anorexic person as treatment
- glucose transporter
- molecule that spans external membrane of cell and transports glucose molecules from outside the cell to inside for use
- nutrients
- chemicals that are no used as sources of energy but required for effective functioning of the body
- what brain area is most sensitive to angiotensin II? what general part of the brain does this specfic area belong to?
- subfornical organ; circumventricular organs (in cerebral ventricle)
- where do the NPY/AgRP neurons project to in the brain? what do they release? where do the POMC/CART neurons project to in brain?
- lateral hypothalamus and release alpha-MSH (decrease feeding); Paraventricular nucleus and LH (increase feeding)
- what does obestatin do?
- works to decrease appetite
- glycogen
- a more complicated molecule than glucose which is stored as reserve fuel; process of conversion called glycogenisis
- what does PYY3-36 do?
- is a potent appetite suppressing stimulus to the hypothalamus
- hypovolemic thirst
- desire to ingest fluids stimulated by reduced volume of extracellular fluid (blood); loss of volume but same concentration of solute
- isotonic
- a solution with the same concentration of salt as mammallian fluids have
- brown fat
- brown adipose tissue found around vital organs in trunk and around cervical/thoracic levels of spinal cord; full of mitochondria that break down molecules and produce heat
- waht do lesions in the lateral hypothalamus cause?
- aphagia (refusal to eat)
- what are the advantages to endothermy? (3)
- greater independance from environmental conditions, greater capacity for oxygen utilization leading to high levels of muscular activity
- semipermeable membrane
- some molecules can pass through it but not all types of molecules
- what 2 combo's of peptide neurons does the arcuate nucleus produce?what does each do?
- NPY/AgRP neurons:stimulate appetite and reduce metabolism; and POMC/CART neurons: inhibit appetite an dincrease metabolism
- glycolysis
- conversion of glycogen back into glucose
- what are the 3 primary acts of insulin?
- promotes glucose as primary energy source, promotes conversion of bloodborne fuels to storable forms, promotes storage of energy sources
- baroreceptors
- located in majore blood vessels/heart that detect a drop in extracellular volume (pressure receptors)
- redundancy
- an important process that is monitored and regulated by more than one mechanism
- angiotensin II has what water conserving actions?
- constricts blood vessels, increases blood pressure, triggers relase of aldosterone which aids in water retention
- ketones
- metabolic fuel source by breakdown of body fats/proteins
- hyperphagia
- excessive eating
- set zone
- range of a variable that the system maintains
- what is the difference between set zones in the lower regions of nervous system compared to higher regions?
- set zones broader in lower regions, set zones narrowest in highest level (the hypothalamus)
- metabolism
- breaking of checmical bonds in food which releases energy as heat
- glucose
- principle sugar used by body for energy; fuels the brain