2j) Co-ordination and Response

Flowering Plants 

Tropism- growth in response to a stimulus e.g. water and light 

+----------------+----------------+---------------------+----------------------------------+
| Response       | Part of plant  | Direction           | Advantage                        |
+----------------+----------------+---------------------+----------------------------------+
| + phototropism | stem tip       | towards light       | maximise the amount of light     |
+----------------+----------------+---------------------+----------------------------------+
| - phototropism | root tip       | away from the light | less chance of drying out        |
+----------------+----------------+---------------------+----------------------------------+
| + geotropism   | root tip       | towards gravity     | more chance of finding moisture  |
+----------------+----------------+---------------------+----------------------------------+
| - geotropism   | stem tip       | away from gravity   | more chance of finding light     |
+----------------+----------------+---------------------+----------------------------------+
| hydrotropism   | root tip       | towards water       |                                  |
+----------------+----------------+---------------------+----------------------------------+

Auxin- plant hormone produces in shoot tips which controls the direction of growth in response to light

Humans 

homeostatis ----> detection of a change in the body 

normal body temperature ----> 37C

Stimulus ----> Response ----> turn back to normal 

Receptors detect stimuli (sense organs) 

Effectors bring about a response to the stimuli 

Central Nervous System

• brain 
• spinal cord 
• send electrical impulses to effector along motor neurone after receptor detects a stimulus 
• coordinate the response

Reflex Arc

• control reactions in humans
• makes a fast automatic response possible 
• body releases the hormone adrenaline automatically 

+-----------+-----------+-----------------+---------------+----------------+-----------+----------+
| Stimulus  | Receptor  | Sensory neurone | Relay neurone | Motor neurone  | Effector  | Response |
+-----------+-----------+-----------------+---------------+----------------+-----------+----------+

Sensory and motor neurone:

The Eye: 

Different types of hormones;

Name of gland	Hormone	What does it do?
Pituitary	ADH	water regulation
Pancreas	insulin	low blood pressure
	glycogen	high blood pressure
Adrenal body	adrenaline	physical activity
Ovaries	oestrogen	development of female secondary
	progesterone	regulates the menstrual cycle
Testes	testosterone	development of male secondary characterists