Communication Systems

Description

Undergraduate A2 Biology (Communication) Note on Communication Systems, created by siobhan.quirk on 11/11/2013.
siobhan.quirk
Note by siobhan.quirk, updated more than 1 year ago
siobhan.quirk
Created by siobhan.quirk almost 11 years ago
153
1

Resource summary

Page 1

Conditions that cells require to work properly: temperature pH humidity water concentration (of enzyme/substrate) cofactors and prosthetic groups inhibitors aqueous environment - keeps the substrate and products in solution freedom from toxins Stimulus: is any change in the environment that causes a responseE.g.: External - temperature, pH, salinity. length of day, sunlight         Internal - temperature, toxins in blood, blood glucose levelsResponse: a change in behaviour or physiology as a result of a change in the environmentE.g. sweating, shivering       Hibernating due to food shortage       Horse loses its coat due to increase in temperatureRapid change: bright light to dim light - pupil sizeA good communication system is required to ensure that these different parts of the body work together effectively.A good communication system will: cover the whole organism enable cells to communicate with each other enable specific communication (target cells) enable sufficiently rapid communication enable both short term and long term responses Cell SignallingTwo major systems of communication that work by cell signalling: neuronal system - usually rapid hormonal system - enables long term responses Once cells have received an external signal (stimulus) there will be a sequence of changes inside the cell, involving enzymes, leading to a change (response).HomeostasisConditions that need to be kept constant: body temperature blood glucose concentration blood salt concentration water potential of blood blood pressure carbon dioxide concentratin Negative FeedbackStimulus -> receptor -> communication pathway -> effector -> responseReceptors - temperature, pH, pressureEffectors - muscle tissue or glandsCommunication pathway - nervous tissue, endocrine tissue (glands) and circulatory system (coordination centres in CNS)Coordination involves comparing the input from the receptor with a set value to determine whether or not a response is required.Positive FeedbackLess commonOptimum condition -> change away from optimum -> receptor detects change -> communication system informs effector -> effector reacts to increase change  -> change away from optimum (repeats)E.g.As the cervix begins to stretch the change is signalled to the anterior pituitary gland, stimulating it to secrete the hormone oxytocin. Oxytocin increases the uterine contractions, which stretch the cervix more, which causes more secretion of oxytocin.

New Page

Show full summary Hide full summary

Similar

Communication Key Words
Becca Westwell
Breaking bad news
katherinethelma
The Process of Communicating
Lindsay Thorpe
AQA A2 Biology Unit 4: Populations
Charlotte Lloyd
Preparing for Presentations
Micheal Heffernan
Photosynthesis and Respiration
Jessica Phillips
F214.1 Communication and Homeostasis Biology Revision Cards
Laura Perry
Endocrine System
Riki M
AQA A2 Biology - Chapter 6 Nutrient Cycles
Charlotte Lloyd
Ecosystems
Jessica Phillips
Provide Service to Customers
nancy stokes