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Module 5 > Communication & Homeostasis > Flashcards

Communication & Homeostasis Flashcards

1
Q

Advantages of ectothermy

A
  • do not use energy to keep warm
    —> therefore less food used in respiration
  • more energy & nutrients from food can be used for growth
  • can survive long without food
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2
Q

Advantages of endotherms

A

-Body temperature doesn’t fluctuate with external temperature, therefore can maintain constant temp
-Remain active even when external temperatures are low
-> can take advantage of available prey & escape
-> can live in colder parts of the world

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3
Q

behavioural endotherm responses if too cold

A
  • move into the sun
  • hot drink
  • put more clothes on
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4
Q

Behavioural endotherm responses if too hot

A
  • move out of sun
  • drink cold water
  • panting / gasps
  • remove clothing
  • lying on ground
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5
Q

Behavioural responses of ectotherms that are too cold

A
  • move into the sun
  • lie on surfaces
  • increase body surface area exposed to sun
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6
Q

Behavioural responses of ectotherms that are too warm

A
  • move out of the sun/ go underground
  • reduce body surface area exposed to the sun
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7
Q

Body reactions if body / blood temperature too cold

A
  1. Hypothalamus heat centre stimulated
  2. Shivering
  3. Vasoconstriction
  4. Increased metabolic rate
  5. Piloerection of hairs
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8
Q

body responses if the body / blood temperature is too hot

A

heat loss centre in hypothalamus stimulated
- vasodilation
- decreased metabolic rate
- sweating
- flattening of hairs

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9
Q

Disadvantages of ectothermy

A
  • less active in cooler temperatures
    –> more at a risk of predators (as a result), as unable to escape
  • cannot take advantage of food available when cold
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10
Q

Do smaller or larger organisms have faster rates of respiration

A

Smaller organisms -> bigger SA:V -> faster heat loss -> faster rate of respiration

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11
Q

Excretory organs

A

Liver
Lungs
Kidneys
Skin

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12
Q

Feature of endotherm (ms)

A

Scales / hairs / fur to trap layer of heat

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13
Q

How could positive feedback increase hypothermia’s effects? (4)

A
  1. Lower temp = reduces molecule Ke
  2. Enzyme activity slows
  3. Respiration rate slows
  4. Loss of metabolic heat generated, so more heat lost
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14
Q

How does a negative feedback loop work

A
  1. Stimulus (change away from optimum conditions)
  2. Receptors (detect the change)
  3. Communication system (informs effector & change is signalled to other cells)
  4. Effector (brings about response which…
    - reverses change of conditions
    - causes a return to optimum conditions)
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15
Q

How does a positive feedback loop work

A
  1. Stimulus: Change away from optimum conditions
  2. Receptors: detect change
  3. Communication system: informs effector & change is signalled to other cells
  4. Effector: brings response to increase the change of conditions
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16
Q

How does cell signalling work (steps)

A

A cell releases a signal which is detected & responded to by other cells
(This is done as…)
- signal has specific shape which is complementary to the shape of that of the cell surface receptor
- binds to receptor
causes specific changes in the receptor

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17
Q

How does flattening of hairs occur

A
  1. Hair erector muscles react
  2. Hairs lie flat
  3. Prevents the hair forming an insulating layer of warm air between skin & hair, increasing heat loss
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18
Q

How does sweating occur

A
  1. Sweat glands secrete sweat to cool skin
  2. Heat energy from the body is lost as sweat evaporates from the skin: this heat energy is used to converted H2O (l) to (g)
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19
Q

How is metabolic rate decreased

A
  1. Less thyroxine released from the thyroid gland
  2. Decreased basal metabolic rate as a result
  3. So less heat released from metabolic reactions
20
Q

How is metabolic rate increased

A

More thyroxine is released from the thyroid gland
Increased basal metabolic rate
So more heat released from exothermic metabolic reactions

21
Q

Thermoregulation process (due to the hypothalamus)

A
  • hypothalamus = thermoregulatory centre of the brain
  • regulates body temperature by monitoring blood temperature & initiating responses if too long
  • there are cold / warm receptors in the skin: stimulated as are those in the hypothalamus
    -> response!
22
Q

Toxic waste products excreted

A

Urea (by kidneys)
CO2 (by lungs)
Bile pigments (found in faeces)

23
Q

Weaknesses of endothermy

A
  • lots of energy used to maintain body temperature (especially in cold)
  • needs more food
  • may overheat in hot weather
  • lower proportion of energy & nutrients from food used in growth
24
Q

What are ectotherms

A

They rely on external heat sources to maintain their body temperature therefore, body temp fluctuates with external temp

25
Q

What are endotherms

A

They can use heat from their own metabolic reactions to maintain their internal body temperatures within strict limits
-> these detect external temperatures by hot and cold peripheral receptors

26
Q

What are features of a good communication

A

Enables cell to be in communication with each other
Cover the whole body
Enable short and long term responses
Enable specific & rapid communication

27
Q

What are the two communication systems that work by cell signalling

A

Nervous System
(Neuronal communication: CNS & PNS. The nerve impulses passed along neurons to send info through the nervous system.)
Endocrine system
(Hormonal communication produces hormone)

They both co-ordinate and regulate body functions

28
Q

What do communication systems do

A

Allow animals & plants to respond to changes in internal & external environments

29
Q

What do effectors (/cell/tissues/organs) do

A

Bring about a response

30
Q

What do endotherms do (not temp wise, HEAT wise:

A

Sometimes needed for ms
They GENERATE HEAT (energy) from metabolic processes / respiration

31
Q

What do receptors do

A

Monitor and detect stimuli (changes to the environment)

32
Q

What do to about aquatic ectotherms (e.g think of waters high SHC)

A
  • water temp is way less variable that land due to waters high SHC
    Therefore, it’s easier for these ectotherms to maintain a stable internal body temperature within strict limits
33
Q

What does a negative feedback loop do

A

Reverses the effects of stimulus & brings the system back to optimum

34
Q

What internal conditions are maintained by homeostasis

A

pH
Body temp
Blood pressure
Metabolic waste
Blood glucose / salt / O2 / CO2 conc
Water potential of the blood

35
Q

What is a positive feedback loop

A

It increases the effect of the stimulus and brings the system further away from optimum

36
Q

What is a response

A

How an organism changes its behaviour / physiology

37
Q

What is cell signalling

A

How cells communicate with each other

38
Q

What is homeostasis

A

Maintaining stable internal environment & conditions within narrow limits, despite changes in either/and internal & external environments

Therefore, it maintains optimal conditions for enzyme activity & cell function

39
Q

What is shivering / effects

A

The regular & rapid relaxation & contraction of muscles
Increases respiration rate
More heat released

40
Q

What is vasodilation

A
  1. Muscles in the arteriole walls relax
  2. Arterioles near the skin dilate
  3. More blood flows through the skin capillaries
  4. More heat is lost to the environment
41
Q

What’s vasoconstriction

A
  • muscles in arteriole wall contract
  • arterioles near the skin contract
  • less blood can flow through capillaries in skin
  • less heat lost to environment by radiation
42
Q

What’s an example of homeostatic control

A

Excretion - the removal of toxic waste products of metabolism from the body (via excretory organs)

43
Q

What’s are stimuli

A

External environmental changes

44
Q

What’s piloerection

A
  1. Hair erector muscles contract
  2. Hairs stand on end
  3. Forms the insulating layer of warm air between the skins surface and hairs
  4. So reduces heat loss
45
Q

What’s the standard homeostasis response pathway

A

A negative feedback loop

46
Q

What’s thermoregulation

A
  • an example of a neg feedback loop
    The regulation of constant body temperature (for endotherms)
47
Q

Why is excretion important

A

Prevents build up of toxic waste products of metabolism
If left to accumulate
1. They can interfere with cell processes by altering pH
2. May prevent normal metabolism
3. May act as an enzyme inhibitor & reduce activity

Module 5 (12 decks)

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