5.1: Homeostasis Flashcards
Effects of sweating:
-evaporation->reduce body temp; heat taken from the body/ skin/ blood is used for evaporation; water has a high latent heat of vaporisation
Suggest why shivering occurs during fever:
To increase body temp as it is lower than the ‘new’ set point (even though body is high temp)
The new ‘normal’ body temp is higher, shivering will raise temp of internal environment
Alcohol causes vasodilation. Suggest it is not a good idea to consume alcohol while you’re suffering from hypothermia:
Vasodilation results in more blood nearer to skin surface; will lose (even) more heat/ further heat loss (from body); organs will not be able to maintain function/ metabolism
Name hormones which promote glycogenolysis other than glucagon:
Adrenaline (short term); noradrenaline; thyroxine (long term); growth hormone; glucocorticoid
Explain why glycogen is suitable for energy storage in cells:
Insoluble; unreactive; can’t diffuse out of cell; no effect on water potential; compact/ branched; lots of “ends” for enzyme action
Explain how a high concentration of glucose causes the storage of glycogen in liver cells:
1) increased activity of glycogen synthetase;
2) slow initial effect;
3) ref to figures show an increase;
4) (overall effect) increases glycogenesis;
5) glycogen;
6) lowers activity of glycogen phosphorylase;
7) rapid effect;
8) ref to figures show a decrease;
9) prevents glycogenolysis;
10) glucose binds to allosteric site/ acts as a non-competitive inhibitor
Explain why homeostasis of body fluids in mammals is important:
1) constant internal conditions
2) cells surrounded by/ exchange substances with, tissue fluid
3) (composition of) tf controlled by blood
4) need 1) for efficient metabolism
5) pH affects enzymes
6) temp. affects enzymes
7) ref to enzymes denature at extremes of pH/ temp
8) constant O2 for brain
9) CO2 must be removed (ref to pH)
10) water potential: increase/ decrease -> cells swell/ burst
11) high wp: odema
12) low wp: cells cremate
13) urea = toxic
14) bcg to high: organ failure
15) bcg too low: coma
16) ions conc: enzyme cofactors
17) K+/ Na+ in action potential OR Ca2+ on synaptic transmission
18) hormones: optimum response of target tissues
Describe how an endothermic animal prevents body temperature from decreasing when external temperature has decreased:
1) peripheral/ skin, thermoreceptors/ (heat) receptors, stimulated (by decrease in external temp);
2) (impulses sent to/ blood temperature monitored in) hypothalamus/ sensory cortex;
3) vasoconstriction of, arterioles/ small arteries, to reduce heat loss;
4) (prevents heat loss by) radiation/ conduction/ convection;
5) increased metabolic rate/ metabolism/ respiration, to generate heat;
6) (release of) adrenaline/ thyroxine;
7) shivering/ (involuntary) muscle spasms, to generate heat (energy);
8) erector/ hair, muscles raise, (skin) hair/ fur, to trap, air/ heat
Describe the way in which an endothermic animal, such as a mammal, normally prevents its body temperature from decreasing when the external temperature decreases.
1 peripheral / skin , thermoreceptors / (heat) receptors ,
stimulated (by decrease in external temp) ;
2 (impulses sent to / blood temperature monitored in ) hypothalamus / sensory cortex ;
3 vasoconstriction of , arterioles / small arteries , to reduce heat loss ;
4 (prevents heat loss by) radiation / conduction / convection ;
5 increased , metabolic rate / metabolism / respiration ,
to generate heat (energy) ;
explain how a person with Type 2 diabetes could control the condition by modifying their diet:
Decrease starch; increase cellulose: some sugars
Describe the way in which an endothermic animal, such as a mammal, normally prevents its body temperature from decreasing when the external temperature decreases:
peripheral/ skin , thermoreceptors/ (heat) receptors,
stimulated (by decrease in external temp); (impulses sent to/ blood temperature monitored in) hypothalamus/ sensory cortex; vasoconstriction of, arterioles/ small arteries, to reduce heat loss; (prevents heat loss by) radiation/ conduction/ convection; increased, metabolic rate/ metabolism/ respiration,
to generate heat (energy); (release of) adrenaline/ thyroxine; shivering/ (involuntary) muscle spasms, to generate heat (energy); erector/ hair, muscles raise, (skin) hair/ fur, to trap, air/ heat
Part of CNS that maintains temperature:
Hypothalamus
Part of PNS that maintains body temperature:
Autonomic/ (para)sympathetic (nervous system); skin/ thermoreceptors/ nerve endings in skin
Explain how each of the following adaptations help the animal to control its body temperature.
(i) Elephants have large, thin ears that they move backwards and forwards when hot. [f214 june 13 2ci]
large surface area (to lose heat) ;
(thin) so , blood flows / (named) blood vessel are ,
close to the (skin) surface (to lose heat) ;
(movement) increases air movement over , skin / surface
(to lose heat) ;
Explain how each of the following adaptations help the animal to control its body temperature. Penguins living in cold climates have ‘shunt’ blood vessels. These shunt vessels link arterioles carrying blood towards their feet with small veins that carry blood away from their feet. [f214 june 13 2cii]
blood loses less heat because ,
less blood flows to feet /
warm blood diverted from arterioles to veins
or less blood flows to feet so core body temperature
maintained ;
