Responses to changing environment Flashcards
What is Homeostasis?
Conditions in the body are controlled, to provide a constant internal environment.
The conditions that must be controlled include body temperature, water content, carbon dioxide level, and blood sugar level. Diabetes is a condition where the body cannot effectively regulate the levels of blood sugar.
How is the blood sugar level controlled?
The blood sugar level is controlled by the release and storage of glucose, which is in turn controlled by a hormone called insulin.
The body temperature is normally at 37°C why is this the case?
This is controlled to maintain the temperature at which enzymes work best
How is body temperature controlled?
controlling blood flow to the skin
sweating
shivering
The body’s water content is controlled to protect cells what is this process calle?
Osmoregulation
How is water content controlled by water loss?
the lungs when we exhale
the skin by sweating
the body, in urine produced by the kidneys
Ion salts are controlled to protect the cells by avoiding too much water entering or leaving them, how is this done?
the skin by sweating
the body, in urine produced by the kidneys
What is thermoregulation
This is the process that the body uses to control temperature
Why are temperature extremes dangerous?
high temperatures can cause dehydration, heat stroke and death if untreated
low temperatures can cause hypothermia and death if untreated
The body’s temperature is controlled by the brain explain the three ways that the body can increase or decrease temperature
Hairs on the skin trap more warm air if they are standing up, and less if they are lying flat. Tiny muscles in the skin can quickly pull the hairs upright to reduce heat loss, or lay them down flat to increase heat loss.
If the body is too hot, glands under the skin secrete sweat onto the surface of the skin, to increase heat loss by evaporation. Sweat secretion stops when body temperature returns to normal.
Blood vessels supplying blood to the skin can swell or dilate - vasodilation. This causes more heat to be carried by the blood to the skin, where it can be lost to the air. Blood vessels can shrink down again - vasoconstriction. This reduces heat loss through the skin once the body’s temperature has returned to normal.
Muscles can also receive messages from the brain when you are cold. They respond by shivering, which warms you up.
What are Hormones?
Hormones are chemicals secreted by glands in the body. Different hormones affect different target organs.
How are hormones transported?
The bloodstream transports hormones from the glands to the target organs. Bodily reactions to hormones are usually slower and longer lasting than nervous reactions.
What does the Thyroid Gland do?
Produces thyroxine which controls the rate of metabolism
What does the Pancreas do?
It produces Insulin which controls the blood sugar level
What do the testes do?
Produces testosterone which causes the changes of puberty and stimulates sperm production
