5.1.1-communication and homeostasis Flashcards
what is a receptor
5.1.1.(a)
detect stimulus (internal or external) and signal to effector
what is an effector
5.1.1(a)
receives signal from receptor and carries out a response
what is a communication system
5.1.1(a)
transmits information between receptor and effector that may be far apart
what are the 2 major communication systems and what do they do
5.1.1(a)
-nervous system (electrical impulses)
-endocrine system (hormones)
what communication system do plants rely on
5.1.1(a)
mainly hormonal
what is cell signalling
5.1.1(b)
-idea of specificity
-cell signalling involves molecules that have a specific shape which is complementary to the cell surface receptor
–plants can also respond to soluble materials
what is homeostasis
5.1.1(c)
state of stable internal conditions are kept within the set point
how do organisms respond to changes in the internal environment
5.1.1(c)
stimulus—>receptor—->communication system——->effector——–>response
what is the difference between positive and negative feedback
5.1.1(c)
positive-exaggerates change
negative-counteracts change
explain the negative feedback loop
5.1.1(c)
the receptors detect the change and signal to the effector to carry out the response and bring the condition back to the optimum
explain the positive feedback loop
5.1.1(c)
the receptors detect the change and signal to the effector to carry out the response to amplify the change
explain hypothermia
5.1.1(c)
positive feedback, is when an initial (biological) change is, increased further / exaggerated / AW ✓
lower temperature reduces kinetic energy (of molecules) ✓
enzyme activity, slowed / reduced ✓
respiration rate / metabolism, slowed / reduced ✓
less (metabolic / internal) heat generated ✓
(so that body) temperature drops further
what is thermoregulation
5.1.1(d)
process by which organisms maintain a constant core body temperature (within a range)
what is the difference between ectotherms and endotherms
5.1.1(d)
ectotherms-behavioural responses
endotherms-behavioural and physiological responses-uses heat generated from metabolic processes.
what are some examples of behavioural responses to warm up
5.1.1(d)
-bask in sun
-sit on hot ground
-move more (respiration releases heat)
(opposite for cool down)
what are some physiological responses to cool down
5.1.1(d)
-increase sweat production
-erector pili muscles relax
-vasodilation
-decrease metabolic rate
-shiver
what are the two types of thermoreceptors in the body
5.1.1(d)
-peripheral temperature receptors
-hypothalamus receptors
what do peripheral temperature receptors do
5.1.1(d)
monitor temperature of environment
what do hypothalamus receptors do
5.1.1(d)
monitor temperature of blood
what is the comparison between SA to V ratio and heat loss
5.1.1(d)
large SA to V ratio will have a high heat loss
small SA to V ratio will have low heat loss so can maintain core body temperature
what is one advantage and disadvantage that ectotherms have compared to endotherms
ectotherms-more energy can be used for growth and reproduction
ectotherms may be susceptible to freezing and can be at risk of predators when body temperature is low.