Staying In Balance Flashcards
What does the body do if the temperature gets too high
VASODILATION
Blood vessels dilate causing greater heat loss as heat is lost from the skin surface by radiation
Blood also flows closer to the skin and you sweat
What does the body do if the temperature gets too low
VASOCONSTRICTION
Blood vessels become narrower as less heat is lost off skin surface by radiation
Sweating is reduced and body makes tiny contractions (shivers)
What is negative feedback
What systems are controlled for this
Automatic reversal of change
If temperature too low, brain switches mechanisms to increase it and vice versa
The brain controls nervous and hormonal systems
What is the pancreas and what does it produce
The pancreas is an endocrine organ
It produces a hormone called insulin. This travels around the body in blood
What is the purpose of insulin
Insulin helps regulate blood sugar levels by converting excess glucose in blood to glycogen in the liver
How is diabetes caused
Diabetes is caused by the pancreas not producing enough insulin
This can lead to high blood sugar levels and comas
It can be controlled by injecting insulin or controlling sugar in diet
In plants what are auxins and what do they control
Plant hormones that control growth of shoots and roots and flowering and ripening of fruit
What part of the plant grows towards light (positive phototropism) and against gravity (negative geotropism)
And why
The shoot
Growth towards light increases survival as light is fundamental to photosynthesi
What part of the plant grows away from light (negative phototropism) and in the direction of gravity (positive geotropism)
And why
The roots
Used for anchorage and to absorb water and minerals
How does gravity affect auxins in the plant
In the shoots the hormones increase growth in the lower region, making the shoot bend upwards
In the roots the hormones slow down growth in lower region,
Making root bend downwards
Auxins are made in the shoot tip
How does the shoot bend towards the light
Distribution of auxin is determined by light
When light shines on the shoot, the hormones in direct sunlight move to the shady side
Cells here elongate and divide making shoot bend towards light
What is homeostasis
Controlling body’s internal environment around 37’C where enzymes work best
It balances inputs and outputs, removes waste products to ensure temperature, pH, water,oxygen and carbon dioxide are maintained
Heat produced through respiration maintains body temperature
How do auxins move through the plant and effect its growth
Move through the plant in solution and effect its growth by responding to light (phototropism) and gravity (geotropism)
