Co-ordination and Response Flashcards
What do plants and animals need to be able to do?
-need to be able to respond to changes in their internal and external environment (such as changes in temperature or pH)
-need to be able to coordinate the activities of their different organs
What does the nervous system do?
nervous system coordinated by the BRAIN allows body to respond to changes in environment
What is homeostasis and give two examples of it?
the maintenance of a constant internal environment of a cell or organism
e.g. body water content and body temperature
Why is homeostasis important?
it is critically important for organisms as it ensures the maintenance of optimal conditions for enzyme action and cell function
Give 6 examples of physiological factors that are controlled by HOMEOSTASIS in mammals?
-core body temperature
-metabolic waste (e.g.
carbon dioxide and urea)
-blood pH
-the concentration of glucose in the blood
-the water potential of the blood
-the concentration of respiratory gases (carbon dioxide and oxygen) in the blood
What do homeostatic mechanisms transfer between different parts of the body?
information
What are the two communications systems in mammals that provide information for homeostatic mechanisms to transfer?
the nervous system
the endocrine system
Why do all living organisms need to respond to changes?
for survival
In order to function properly and efficiently, what do organisms have that ensure their internal conditions are kept relatively constant?
they have different control and communication systems that ensure their internal conditions are kept relatively constant
What may happen to the organism if the limits that keep the internal conditions healthy is exceeded?
the organism may die
What does homeostasis maintain in terms of conditions and what does this ensure?
it maintains optimal conditions for enzyme action and all cell functions which ensures that reactions in body cells can function and therefore the organism on a whole can live
What is the core body temperature of a human?
kept close to 37*C
Why is the body temperature of a human very tightly controlled and why?
a change in more than 2*C can be fatal as a temperature drop would stop essential enzymes from functioning optimally
What is body temperature of a human controlled and monitored and where is it?
the thermoregulatory centre in the base of the brain as blood passes through it
What does the thermoregulatory centre contain that allows it to monitor body temperature?
it contains receptors that are sensitive to the temperature of the blood
What does the skin also contain like the thermoregulatory centre that allows it to send nervous impulses to the thermoregulatory centre?
the skin also contains temperature receptors and send nervous impulses to the thermoregulatory centre, the brain then coordinates a cooling or heating response depending on what is required
What is the water lost in the production of urine controlled by?
the kidneys
Can water loss via the lungs or skin be controlled?
NO
What does the hormone ADH control in terms of water loss in urine?
ADH controls the process on how much water is reabsorbed in the collecting ducts depending if the water content of the blood is too high or too low
What is the hormone ADH released by and where is the gland?
the pituitary gland in the brain
What two parts are involved in maintaining homeostasis as it is an automatic control?
the brain stem (or non-conscious part of the brain)
the spinal cord
What kind of control is homeostasis?
involuntary (automatic) control
What may the automatic control systems (e.g. brain stem and spinal cord) involve to maintain homeostasis?
they may involve nervous responses or chemical responses (e.g. via hormones)
What do ALL control systems that carry out co-ordinated responses require?
-a stimulus
-a receptor
-a coordination centre (not all the time)
-an effector
