Response and Regulation GLOSSARY KEYWORDS Flashcards
Homeostasis
Maintenance of a constant internal environment
The test carried out to detect the presence of glucose
Benedicts Test
Vasodilation
an increase in the diameter of blood vessels
Insulin
the hormone released by the pancreas in response to high blood glucose levels
Sweat pore
The opening of the sweat gland on the surface of the skin
Erector muscle
the muscle which attaches to a hair and pulls it upright when contracted
Glycogen
The chemical that is stored in the liver after conversion from glucose
sweat duct
the tube that carries sweat from the gland to the pore
type 2
the type of diabetes which is linked to obesity
sense organ
a group of receptor cells
electrical impulse
the form of the message that is transmitted along a neurone
negative feedback
the mechanism which restores homeostasis
glucagon
the hormone released by the pancreas to increase blood and glucose levels
stimulus
a change in the environment
vasoconstriction
a reduction in the diameter of blood vessels
pancreas
the organ which secretes insulin into the blood
central nervous system
the brain + spinal chord
neurone
a nerve cell
liver
the organ which stores glycogen
hormone
a chemical messenger
type 1
the type of diabetes caused by the pancreas being unable to produce insulin
positive Phototropism
a growth response towards an unilateral light source
what is a sense organ
A group of receptor cells that respond to specific stimuli
name the sense and stimuli for EYES
sense = sight
stimuli = light
name the sense and stimuli for NOSE
sense = smell
stimuli = chemicals
name the sense and stimuli for TONGUE
Sense = taste
stimuli = chemicals
name the sense and stimuli for EARS
sense = hearing
stimuli = sound
name the sense and stimuli for SKIN
sense = pressure + pain
stimuli = touch + temp
how is the information from sense organs passed to the CNS (central nervous system)?
Electrical impulses along neurones
what does the nervous system consist of
brain, spinal chord and nerves
what doe the CNS (central nervous system) consist of
brain and spinal chord
what is a stimulus
a change in the environment
what are the properties of withdraw reflexes
rapid, automatic, protective
a diagram of a reflex arc
stimulus
receptor
sensory neurone
relay neurone
synapse
motor neurone
effector
define homeostasis
maintaining a stable internal environment
why is homeostasis so important
enzymes only work within a narrow range of temperature and pH
how does the body regulate temperature
controlled by the nervous system.
the hypothalamus (in brain) detects the change and sends electrical signals to the skin
when body temp drops, the skin will…
- blood vessels constrict (vasoconstriction)
- hair erector muscles contract = erect hairs
- muscles shiver
How does contraction of hair erector muscles retain heat?
The hairs stand upright trapping a layer of insulating air next to the skin
How does vasoconstriction help to retain heat
Less blood travels to the surface of the skin so less heat is lost to the surrounding environment
How does shivering increase body temperature
Muscles are contracting, respiring and releasing heat
How does the skin react when body temperature arises above 37C?
- Blood vessels dilate (vasodilation)
- Hair erector muscles relax and hairs flatten
- Sweat glands produce sweat
How does vasodilation lead to increased heat loss from the body?
More blood travels to the surface of the skin so more heat is lost to the surrounding environment
How does relaxation of hair erector muscles lower body temperature?
The hairs lie flat and there is no insulating layer of air, so heat is lost to the surrounding environment
How does sweating help to lower body temperature?
The sweat glands produce sweat
The sweat travels along the sweat duct, out through the sweat pore and onto the surface of the skin
Body heat is used to evaporate the sweat
How are blood sugar levels controlled?
Hormone system.
The pancreas detects changes in blood glucose levels and releases hormones into the blood
What is a hormone and what group of chemicals does it belong to?
A chemical messenger carried by the blood
It is a protein
What might cause an increase in blood glucose levels?
High carbohydrate meal
How does the body respond to bring down blood glucose levels?
- The pancreas secretes insulin into the blood
- The insulin travels to the liver
- The liver removes soluble glucose and converts it to
insoluble glycogen, which it then stores
How does the body respond to a decrease in blood glucose levels?
- The pancreas secretes glucagon into the blood
- The glucagon travels to the liver
- The liver converts insoluble glycogen into soluble
glucose, which it releases into the blood
What might cause a decrease in blood glucose levels?
Fasting
Exercise
What is diabetes?
A disease in which a person has a high blood glucose level
What causes type 1 diabetes?
The pancreas is unable to produce insulin
What causes type 2 diabetes
The body cells are not able to respond properly to the insulin that is produced
What is a symptom of diabetes?
The presence of glucose in the urine
(Also thirst, tiredness, frequent urinating and loss of weight)
How is diabetes diagnosed?
Testing glucose levels in the blood or urine
How is type 1 diabetes treated
Insulin injections
Low carbohydrate diet
Transplant of pancreatic tissue
How is type 2 diabetes treated?
Low carbohydrate diet
Increased exercise
What reagent would be used to test for glucose in urine?
Add Benedict’s reagent and heat strongly
A positive result is a colour change from blue to brick-red
What is ‘negative feedback’?
Changes are reversed and values are restored to their normal range by the nervous system (temperature) or hormonal system (blood glucose)
What are the problems associated with obesity?
Increased risk of type 2 diabetes
Strain on heart and joints
What is tropism?
A growth response to a unilateral stimulus
What is positive phototropism?
A growth response towards a light source
What is positive geotropism?
A growth response towards gravity
Which parts of a plant demonstrate positive phototropism?
Plant shoot tips
Which part of a plant demonstrates positive geotropism?
Root tips
Which plant hormone controls positive phototropism?
Auxin
What equipment could you use to investigate phototropism in plants?
A light box with light entering from one side only
What could be used as a control experiment when investigating phototropism in plants?
A plant on a rotating disk which will receive light on all sides
