Homeostasis and temperature regulation Flashcards
(23 cards)
Homeostasis definition
The maintenance of a constant internal environment in the body even when external conditions change
Why is homeostasis important
Crucial chemical reactions involving enzymes can happen at an optimum rate
What is regulated in homeostasis
- blood sugar levels
- water levels
- internal temperature
what do receptors do
Detect a change in stimuluis
what is a stimulus
a change in the environment
What do coordinators do and what are they
Spinal chord, brain or a gland.
They receive information from receptors, process the information and initiate a response
what do effectors do and examples of them
Muscles - contract
Glands - secrete a hormone, which would restore the optimum condition again
What is the average human body temperature and what is it controlled by
37 degrees C
controlled by the thermoregulatory centre, in the hypothalamus. - contains receptors sensitive to the temperature of blood.
Skin also has temperature receptors and sends impulses back to thermoregulatory centre
What happens when we get TOO COLD
Thermoregulatory centre detects this and sends E.I to the brain
- Vasoconstriction: blood vessels constrict and become narrower, so less blood flows near the surface of the skin, reducing heat loss by radiation from skin to environment
- reduced sweating
- shivering: rapid muscle contraction which increases rate of resp. increasing amount of energy lost as heat
- piloerection (not in humans) - increased trapped air, increased insulation, less heat lost by radiation
What happens when we get too HOT
Thermoregulatory centre detects this and sends E.I to the brain to try and reduce heat loss
- Vasodilation: blood vessels widen, and bring blood closer to the surface of the skin and more heat energy is lost by radiation from the skin to the environment
- sweating: sweat is produced by sweat glands and is released onto the skin. heat from skin causes sweat to evaporate increasing heat lost to the environment - heat is transferred from skin: evaporation of water in sweat causes cooling
What is osmoregulation
The control of water levels and mineral ions in the blood
what’s a hypotonic solution
A more dilute solution
What is a hypertonic solution
A more concentrated solution
What happens to cells in a more dilute solution
Cells swell and burst
What happens to cells in a more concentrated solution
Cells shrivel
What is majority of water from the body lost as
- sweat from the skin
- urine from the kidneys
- water vapour from the lungs when we exhale
Where is insulin produced
By the pancreas
What organ is responsible for controlling blood glucose concentration
The pancreas
What happens if blood glucose is TOO HIGH
- receptors in pancreas detect change
- pancreas secretes insulin into the blood stream
- insulin tells the liver to convert the glucose into glycogen
- blood glucose levels fall
What happens if blood glucose levels are TOO LOW
- pancreas detects change and secretes glucagon
- glucagon tells liver to break down the glycogen back into glucose
- blood glucose levels rise
What is type 1 diabetes
A disorder where the pancreas fails to produce enough insulin - often detected from an early age and is genetic.
Treatment is injecting insulin
What does a person with type 1 diabetes have to do
- Monitor their blood sugar levels throughout the day
- Their levels of physical activity and their diet affect the amount of insulin needed
What is type two diabetes
Where a person’s body cells no longer respond to insulin. Most common in older people
Treatment is a balanced healthy diet and exercising more. A high BMI is a risk factor for type 2 diabetes
