Homeostasis Flashcards
(24 cards)
Definition of homeostasis
Various processes keeping the internal environment constant by controlling levels of
1) WATER
2) IONS
3) pH
4) GLUCOSE
5) TEMPERATURE
6) OXYGEN + CARBON DIOXIDE CONCENTRATIONS
7) ENZYMES
8) HORMONES
Explain homeostasis
Result of coordination of your nervous system, hormones and body organs.
What is negative feedback?
A concept of control that occurs when the body seeks to maintain an optimal set-point and if the internal conditions deviate from this, the body reacts and brings it back towards the set point.
Describe control of glucose concentrations by liver
INSULIN stimulates the liver to take up
glucose from the blood ——-> to glycogen
Because too much glucose would affect the OSMOTIC BALANCE and cause water to move out of cells. However our cells constantly respire and need a steady supply of glucose.
Describe role of insulin and glucagon from the pancreas
A rise of glucose is detected by the pancreas and as a result it produces INSULIN.
When a drop of glucose is sensed, the pancreas produces GLUCAGON.
What does insulin do?
Glucose –> glycogen
What does glucagon do?
Glycogen —-> glucose
Symptoms of type 1 diabete
Being Thirsty Feeling hungry Feeling tired all the time Blurry eyesight Losing weight Urinating more often Stomach pain Rapid breathing Dry skin and mouth Nausea and vomiting
Treatments of type 1 diabete
INSULIN
HEALTHY DIET
EXERCISE
Explain the role of insulin in type 1 diabete
Insulin is a hormone , released by pancreas that converts
Soluble glucose —-> insoluble glycogen
Makes glucose levels drop
Explain role of healthy diet in Type 1 diabete
Avoid sugary drinks as they put glucose levels up high + quickly
Dont eat food with large amounts of calories and fat
Include carbohydrates to meal otherwise insulin may cause glucose levels to drop too low
Explain role of exercise in Type 1 diabete
Regular excercise helps control the amount of sugar in the blood. It increases the insulin sensitivity so after exercise, your body doesn’t need as much insulin to process carbohydrates.
- lower blood pressure
- Better control of weight
- more energy
Draw diagram of skin
—see book
Describe maintenance of a constant internal body temperature by insulation
INSULATION - by skin that enables them to conserve heat by having SUBCUTANEOUS FAT beneath the skin. This is because it does not conduct heat very well. Mammals have fur or air, which traps a layer of air close to the skin. Air is a poor conductor of heat so air pockets in the fur reduce loss of heat by keeping convection current of air away from the warm surface of skin.
Describe maintenance of a constant internal body temperature (x4)
Insulation
Sweating
Shivering
Brain
Describe maintenance of a constant internal body temperature by brain
The HYPOTHALAMUS in the THERMOREGULATORY CENTER of the brain monitors the temperature of the blood that passes through it and takes action if temp. Starts to deviate from the set point, it takes actions. It sends impulses to the arterioles (skin) causing them dilate and let more blood flow nearer the skin. —-> this is because thermal energy from blood is lost through radiation of heat from the skin and convection helps carry away this heat)
= vasodilation
Describe maintenance of a constant internal body temperature by sweat glands
Sweat glands release sweat through sweat pores in the skin. This thin film of sweat consists of mostly water. When the water evaporates, it takes away thermal energy from the skin, cooling it down.
—-> lose heat
Describe maintenance of a constant internal body temperature by rhythmic muscles
Rhythmic muscles’ contraction causes shivering , with the increased respiration release HEAT so temperature will increase.
What is vasodilation ?
Vasodilation happens when the body’s temperature is ABOVE 37 degrees celsius.
Arterioles dilate so get wider which sends more blood to the skin surface capillaries to maintain an internal body temperature of 37 degrees. This is because thermal energy from blood is lost through radiation of heat from the skin and convection helps carry away heat.
What is vasoconstriction?
Vasoconstriction happens when body temperature is below 37 degrees.
Arterioles constrict to go narrower so less blood goes to the surface to keep body warm.
Define the term gravitropism
A response in which parts of a plant grow towards or away from gravity.
Define the phototropism
A response in which parts of a plant grow towards or away from the direction from which light is coming.
What is auxin?
A plant hormone that controls direction of growth. Auxin always moves to the shaded side of the plant (away from light) so that the plant bends towards the light to get more light for photosynthesis.
Describe the use in weedkillers of the synthetic plant hormone 2,4-D
2,4-D is a synthetic plant hormone used in weedkillers that affects BROAD-LEAVES PLANTS (usually weeds) because it affects the rate of cell division so it occurs too quickly for the plant to maintain.
