Homeostasis and the Cell

What is homeostasis:

The ability of the body to maintain its internal environment within acceptable ranges, despite the changing external environment.

What is dynamic equilibrium:

A condition that remains stable within fluctuating limits.

What is negative feedback:

A mechanism used to maintain the body's internal environment the same (homeostasis. it reverses change.

What is positive feedback:

A mechanism that maintains the direction of the stimulus and accelerates it, to achieve a specific outcome. If prolonged, positive feedback can cause death, because it causes an escalation in response, which is unstable.

What does the receptor do:

It detects the variation in the set point and sends messages to the control center.

What is the control centre:

Is the part of the brain that processes information about the change and sends a message to a specific effector.

Give an example of a control centre:

Hypothalamus (responsible for keeping the body temperature the same)

What is an effector:

A muscle or a gland that reverses change from a set point.

Give an example of an effector:

Skeletal muscles (used to make the body temperature rise by quickly contracting and relaxing, which causes friction and makes heat), sweat glands (used to lower the body temperature by producing sweat, which takes heat out of the body) smooth muscles in the stomach (contracts to empty the stomach)

Give an example of a negative feedback:

When food enters the stomach, smooth muscles contract and it is mixed and emptied from the stomach. When the body temperature falls, skeletal muscles make you shiver in order to make your body temperature rise back up and your blood vessels contract to keep the heat close (vasoconstriction).

Give an example of positive feedback:

Childbirth, lactation, fruit ripening, blood clotting and fever.

What is thermoregulation:

The ability to maintain a constant body temperature.

What is the body temperature of humans:

37°C

What is osmoregulation:

The ability to maintain a constant water balance.

What is waste management:

The ability of the body to rid itself of harmful wastes. Necessary for maintaining homeostasis.

What is amplification:

The process of making many copies of a specific DNA or RNA molecule.

What is the protein pumps:

A type of active transport protein in cell membranes that move molecules across the membrane, often against their concentration gradient, using energy, typically from ATP.