3.1 Coordination and Response
Transcript of 3.1 Coordination and Response
The changes in external and internal environment faced by an organisms
A changes in the environment that can make an organisms react and cause response in the body are called stimuli
External stimuli are the changes that occur outside the body
Internal stimuli are the changes that occur inside the body
Ex of external stimuli: light, smell, temperature, touch, sound, taste and pressure
Ex of internal stimuli: sugar level in blood, osmotic pressure in blood and body temperature
a. To enable organisms to move, feel pain and taste
b. To enable organisms to adjust to changes in the environment
c. To protect the organisms from harm
d. To ensure the survival
A response is a result of a reaction towards stimuli
In plants, response made is generally a growth movement towards the external stimuli called tropism
Nastic movement – movement of part of plant in response to external stimuli
Tactic movement – response that made up by the whole organisms to external stimuli
Stimulus
Receptor
Afferent pathway (Afferent Neurone)
Integrating
centre(brain)
Effectors
(muscle)
Efferent pathway (Efferent Neurone)
causes
Response
1. The receptor in the sensory organs detect the stimulus. Triggers a nerve impulse to produced in afferent pathway.
2. The afferent pathway carries the nerve impulse to the integrating centre which is in the brain
3. The brain interprets the information and sends out another nerve impulse
4. The efferent pathway then carries the nerve impulse from the brain to the effector
5. The effector such as muscles or glands reacts to cause a response to the stimulus
Integrating centre (brain)
Receptors in the hypothalamus
Stimulus (high glucose level in the blood)
Normal glucose level in the blood
Effector (pancreatic glands)
Response (activities to decrease high glucose
level)
A change in blood sugar level is detected
By negative feedback
Glucose level is lowered
Sugar level in our blood will increase when we take too much carbohydrate or sweet food
This situation will be detected by hypothalamus
The endocrine system and nervous system control and coordinate functions in the body maintain a constant sugar level through a negative feedback system
-ve feedback operation counteract the changes in the internal environment in order to restore it to normal
Coordination is the process involved in the detection of stimulus and the subsequent response of the organism towards the stimulus
It involves both nervous system and endocrine system