5.1 communication and homeostasis Flashcards
What four things has to be maintained in order for an organism to survive
P, T,A,F
•PH
•Temperature
•Aq Environment
•freedom from toxins and excess inhabitors
What two changes can stimuli come from?
I..E
Internal environment
External environment
Changing internal environment?
E, TF
•Cells are protected by epithelial tissue e.g skin and bark.
• internal cells and tissue are bathed and tissue fluid.
One waste product is carbon dioxide. What happens if it builds up in the tissue fluid.
P
It will alter the pH of tissue fluid may disrupt enzymes.
How do we get rid of waste e.g. carbon dioxide as it builds up?
How will it affect the pH?
Breathing rate increases and expel carbon dioxide from body, reducing pH.
Changes in external environment in terms of behaviour and physiology?
What is the stimulus and the response?
•External conditions put pressure to change behaviour or physiology.
• environmental change= stimulus
• Change in behaviour of physiology= response
What is an example of an external change in terms of seasonal changes and animals?
Slow environment change e.g winter Arctic fox has white thick coat
Why are multicellular organisms more efficient than singular celled organisms?
•Cells are differentiated.
>Meaning cells are specialised to perform particular functions .
In a multicellular organism what can groups of cells form?
T, O, OS
Tissue and organs to form an organ system
What five factors enables a good communication system
WB,Eo,SC,R,s..I
• covers the whole body
• Enable cell to communicate with each other
• Enable specific communication.
• enables rapid communication
• Enables both short time and long-term responses
Define homeostasis
Maintain conditions in the body despite internal and external environment changes.
What are the six things that need to be maintained by homeostasis?
T,g,s,w,p,cd This
•Body temperature
•Blood glucose concentration
•Blood salt concentration
•water potential of the blood
•blood pressure
•carbon dioxide concentrations
What is the mechanism/standard response pathway?
CP
Stimulus-> receptors-> communication pathway(cell signalling)-> effectors-> response
What is negative feedback?
M,op,r
To maintain a constant internal environment any change away from optimum condition must be reversed
Draw the negative feedback loop!
Optimum Changes
Condition Away from optimum
Return to. Receptors detect
Optimum Change
Effector react. Communication.
To reverse back System informs
Effector
Meaning of Positive feedback
We detect a change and we increase the change
What is one example of positive feedback with enzymes?
T,l/h rr, rH,lrr
Enzymes increase the temperature= High rate of reaction, When we lower temperature we get lower rate of reaction Reducing the amount of heat produced= less reactions
What is a ectothermic?
Relies on E..
Relies on external sources of heat to maintain body temperature
What is an endotherm?
Organisms that use heats from metabolic reactions to maintain body temperature.
How do ectotherms absorb heat from the environment? 3
Su a,Sa, e lsa
• Move in to a sunny area
• lie in a warm surface
• expose a larger surface area to the sun
What will ectotherms due to decreased temperature?3
S, bs,u
• Move out the sun
• reduce the body surface exposed to the sun
• move, underground
What is three things the skin will do in response when the body is too hot
• sweat gland secrete fluid on skin surface
• hair and feathers lie flat
• vasodilation of arterials
Advantages of ectotherms
• survive with less food as they need to respire as much relay on external temp.
•
Disadvantage of enotherms?
• more food to respire
•chances of overheating
