1.6 - Response and Regulation Flashcards
What does the receptor do?
Receives the stimulus by one of the 5 senses
What does the sensory neurone do?
Takes electrical impulse from the receptor to the CNS
What does the CNS do?
Brain- involves conscious decisions with the spinal cord
Spinal cord- automatic responses
What does the motor neurone do?
Takes the electrical impulse from the CNS to an effector
What does the effector do?
Response by the body
Usually muscular but can be glandular
What is a tropism?
An involuntary response involving the growth or turning movement of a plant in response to an environmental stimulus
What is photo and geotropism?
Photo- response by plant to light
Geo- response by plant to gravity
How could we measure positive geotropism?
By measuring the length and angle of roots
What happens to the plants when light is coming from all directions?
The plants will bend in all directions from where they received the light
How does light affect the growth?
- shoot grows towards the light
- when a shoot receives light from 1 side, the auxin is found on the shaded side so elongates
- the shoots bend towards the light
How does gravity affect the growth of a plant?
- the shoot grows up away from gravity
- root grows towards gravity
- in the shoot the auxin stimulates it to grow more on the lower side
- shoot bends upward
- in the root the auxin builds up on the lower side but auxin slows down growth
What is homeostasis?
Keeping the internal conditions of the body the same
What is negative feedback?
The mechanism by which the body maintains conditions within particular limits
What is glycogen?
Insoluble carbohydrate stored in liver
What is glucagon?
A hormone released by the pancreas which raises blood sugar
What is glucose?
A soluble sugar carried in blood
What is insulin?
A hormone that decreases the blood sugar and is released by the pancreas
When would the blood sugar rise?
After eating a meal high in carbohydrates
What does insulin do?
It changes soluble glucose into insoluble glycogen which is stored in the liver
What does glucagon do?
It changes insoluble glycogen into soluble glucose that enters the bloodstream
Describe how to test a patient’s urine for sugar
- Collect the patient’s urine into a test tube
- Put a few drops of Benedicts Reagent into it
- Put test tube in a water bath at 80 degrees for 5 minutes
- If the urine contains sugar it should be brick red
Describe what happens in the body when it is too hot
- sweat: heat of skin evaporates the sweat and cools the skin
- vasodilation (blood vessels get wider) more blood flow through capillaries as heat is lost to the atmosphere and it cools the body. Causes redness in skin
- hairs lie flat: less air trapped for insulation
Describe what happens in the body when it is too cold
Shivering- contraction and relaxation of muscles produces heat
Sweat gland stops releasing sweat
Hairs are raised: trap a thicker layer of air against the skin surface providing more insulation
-air is a poor conductor allowing less heat to escape
-vasoconstriction (capillaries near surface constrict) so less blood goes to the surface. Causes pale skin when cold
What is the role of hair?
They control the body temperature. They lie flat when we are warm, and rise when we are cold
