2.8 - Homeostasis Flashcards
What is homeostasis?
The maintenance of constant internal environment to keep conditions at an optimum
What are responsible for homeostasis?
Nervous system and hormones
What are the differences between hormones and the nervous system?
1) its type of message is
2) carried by the…
3) speed of transmission is
1) chemical, electrical
2) blood, neurons
3) slow, fast
Where are hormones produced?
Endocrine glands
Which hormone is involved in the regulation of sugar (glucose) in the blood?
Insulin
What is glucose needed for?
respiration
When your body is low in glucose what are the effects on the pancreas, liver and blood glucose level?
Pancreas - Insulin not secreted (released) into blood
Liver - Doesn’t convert glucose into insoluble glycogen
Blood glucose level - increase
When your body is high in glucose what are the effects on the pancreas, liver and blood glucose level?
Pancreas - Insulin is secreted (released) into blood
Liver - Convert glucose into insoluble glycogen
Blood glucose level - decreases
What is a negative feedback mechanism?
mechanisms to lower raised levels of something, and to raise reduced levels of something
Explain what happens in your body regarding controlling the level of blood glucose after a meal?
1) Glucose is absorbed from the small intestine into the blood
2) The pancreas detects an increase in glucose in the blood
3) The pancreas releases insulin which travels in the blood to the liver
4) The liver converts excess glucose into insoluble glycogen for storage and the blood sugar falls
5) Pancreas stops producing Insulin
Explain what happens in your body regarding controlling the level of blood glucose following exercise?
1) During exercise glucose from the blood is quickly used up for respiration to keep the muscles moving
2) Pancreas detects decrease in glucose in blood
3) Pancreas releases glucagon which travels in the blood to the liver
4) Liver converts stored glycogen back into glucose and the blood sugar levels rise
5) Pancreas stops producing glucagon
Why does the skin help maintain the body temp at 37*C ?
Temp at which the body’s enzymes work best
What is in the skin?
blood capillaries hair erector muscle hair sweat sweat pore sweat duct sweat gland
When we are too warm what happens to the hairs on our skin?
1) hair erector muscle relaxes, lowering the hair
2) thin insulating layer of air is trapped above the skin
3) more heat is lost to the environment
When we are too cold what happens to the hairs on our skin?
1) hair erector muscles contract, raising the hair
2) hairs trap a thicker layer of air above the skin
3) air insulates skin against heat loss
What is vasoconstriction?
The response to being cold. Process involves the narrowing of blood vessels at the skin surface to reduce heat loss through the surface of the skin
What is vasodilation?
Response to being too hot. Process includes the widening of blood vessels at the skin surface to increase heat loss through surface of skin
Why do you shiver when cold?
Shivering is caused by involuntary contractions of your muscles. Muscle contractions require energy from respiration which releases heat. Heat is used to warm the body up.
Why do you sweat when hot?
Sweat is produced by the sweat glands and travels up the sweat duct and out of sweat pore onto the skin surface. Here it will evaporate taking excess body heat with it. Hence, cooling you down.
What do plants need for photosynthesis?
Light and water
What is a plant tropism?
A plats growth response to light, gravity or water
What is a positive tropism?
When a plant grows towards the stimulus
What is phototropism?
A growth response to where the stimulus is light
What is Geotropism?
A growth response where the stimulus is gravity
Stem response to light is _____ phototropism (grows towards light)
Root response to gravity is _____ geotropism (grows in the direction of the force of gravity)
Positive or negative
Both positive
Where is auxin ( plant hormone) made?
tips of growing stems and roots (meristems)
What does Auxin do?
Changes the rate of elongation in plant cells, controlling their length
How do stems and roots respond to high concentrations of auxin?
Cells in stems grow more
Cells in roots grow less
In a stem, the shaded side contains more auxin and grows ____ (longer, less) causing the stem to bend ____ (towards or away) the light
longer, towards
When light covers the whole shoot the auxin moves ____ down the shoot and all the cells elongate at the same rate
evenly
In a root, the shaded side contains more auxin and grows ____ (longer, less), causing the root to bend ____ (towards or away) from the light
less, away
What happens to the roots if a young plant is placed horizontally?
the bottom side contains more auxin and grows less, causing the root to bend in the direction of the force of gravity
What happens to the stems if a young plant is placed horizontally?
the bottom side contains more auxin and grows more, causing the stem to bend upwards against the force of gravity
What is diabetes?
A condition in which the blood glucose levels remain too high
What is type 1 diabetes caused by?
Damage to the beta cells in the pancreas which produces Insulin. The problem can be inherited, also caused by catching particular viruses and the body’s response to them.
How can type 1 diabetes be controlled?
Following a low sugar/ carbohydrate diet
Injecting Insulin
Possible transplant of pancreatic tissue
What us type 2 diabetes caused by?
A person’s body becoming resistant to Insulin. It can be controlled by diet and exercise
What things do people with type 1 diabetes need to monitor?
blood sugar levels
levels of physical activity
their diet (affects the amount of insulin needed)
What factors lifestyle factors contribute to the development of type 2 diabetes?
Eating too much food over long period of time
Drinking too much alcohol
Misuse of drugs
What are the problems with drinking alcohol?
Slows down the body’s reaction time
Its addictive
It could cause long term physical damage to major organs such as the liver and circulatory system
