Communication,Homeostasis & Energy Flashcards
Need for communication systems in organisms?
- organisms need to be able to to respond to changes in internal/external environment
- coordinate activities of different organs
Eg of physiological factors controlled by homeostasis ?
Core Body temperature
Metabolic waste
Blood pH
Conc of glucose in blood
Water potential of blood
Conc on respiratory gases in blood
What does nervous system consist of and what does it help ?
Central Nervous System (CNS)—> brain/spinal cord
Peripheral Nervous System (PNS)—> all nerves in body
- allows us to make sense of surroundings /respond to them , as well as coordinate/regulate body functions
- info in nervous system sent through nerve impulses
What are neurones and nerves ?
Neurones - electrical signals that pass along nerve cells
Nerve - bundle of neurones
What do neurones do?
Coordinate activities of sensory receptors , decision making centres in CNS and effectors
What is the endocrine system ? How does it act as communication system?
Endocrine glands that produce hormones in animals are collectively known as ENDOCRINE SYSTEM
- hormones are chemical substances produced by an endocrine gland/carried by blood
They transmit info from one part of organism to another /alter activity of one or more specific target organs
- used to control functions that dont need immediate responses
Importance of homeostasis ?
Homeostasis keeps internal body conditions within restricted limits
Controls:
Temperature (vital for enzyme activity)
PH (vital for enzyme activity)
Blood Glucose conc
Why does blood glucose conc need to be controlled?
Glucose in blood affect WATER POTENTIAL of blood / availability of respiratory substrate for cells
Eg of how plants carry out homeostasis ?
Stomata control diffusion of gases in/out leaves
- stomata respond to changes in :
LIGHT- open in higher light intensity/close in darkness
CO2 levels - open when low CO2 conc in air spaces in leaf/close when high CO2 conc in leaf
This regulation of stomata aperture balances need for CO2 with need to minimise water loss
How is negative feedback controlled?
Receptors detect deviations from the normal range (stimuli) which causes a corrective mechanism to return factor Back to normal range
2 corrective mechanisms : one for when factor is too low
One from when factor is too high
These corrective mechanisms can involve the endocrine/nervous system to transfer info to effector /carry out response
What happens in positive feedback?
The original stimulus produces a response that causes the factor to deviate even more from normal range
What is homeostasis?
Regulation of internal conditions of a cell/organisms to maintain optimum conditions for function , in response to internal/external changes
Eg of positive feedback to cause activation ?
Blood clotting after injury :
- platelets become activated /release a chemical - trigger more platelets to become activated and so on
- platelets form blood clot
- process ends with negative feedback when body detects blood clot has formed
What is cell signalling /why is it important?
Process by which cells communicate with each other
- allows multicellular organisms to control/coordinate their bodies and to respond to their environments
Stages of cell signalling?
Stimulus received by receptor cell
Stimulus converted to a signal to be passed on —> TRANSDUCTION
Signal transmitted to effector that can detect it /appropriate response made