The Basics of Homeostasis
What is homeostasis?
Maintaining a stable internal environment.
What is a stimulus?
A change in the environment that the body detects.[appropriate example included]
What is the human body temperature?
37 degrees celsius.
What is glucose used for?
It is the body’s main energy source.
What is a synapse?
The tiny gap between the axon terminal of one nerve cell and the dendrite of the next nerve cell.
Why does the body need homeostasis?
The body needs homeostasis to keep its internal conditions steady so it can stay healthy and work properly.
Give an example of any stimulus and the response.
[any appropriate example]
Define vasodilation.
Blood vessels widen to release heat.
What does insulin do?
Lowers blood glucose by helping cells absorb it.
What is a hormone?
A chemical messenger released by glands.
Give two examples of conditions kept stable.
Body temperature, blood glucose, water balance, pH.
What is an effector?
A muscle/ gland/ cell that executes a response to bring the body's internal environment back to balance
Define vasoconstriction.
Blood vessels narrow to conserve heat.
What does glucagon do?
Raises blood glucose by releasing stored glucose from the liver.
Give one difference between the nervous and the endocrine system.
Nervous = fast electrical signals; Endocrine = slower chemical signals.
If someone drinks a lot of water quickly, what does the body do to return it back to normal levels.
The kidneys remove the extra water by making more urine, which helps return water levels to normal.
A student accidentally touches a hot metal tray. Describe the stimulus, the receptor, the effector, and the response in this situation.
Stimulus: Heat from the hot tray. Receptor: Temperature/pain receptors in the skin. Effector: Arm muscles. Response: The hand quickly pulls away.
How does sweating help to cool the body?
Sweat evaporates, removing heat from the skin.
Which specific cells of the pancreas produce and secrete both insulin and glucagon.
Alpha cells= Glucagon. Beta cells= Insulin.
What is a reflex arc?
A fast, automatic response pathway that bypasses the brain.
Explain how two different body systems work together to maintain homeostasis. Give an example.
Two body systems communicate and support each other to keep the internal environment stable. Example: The nervous system detects a change (like low water levels) and signals the endocrine system, which releases hormones to fix the problem.
What's the difference between negative and positive feedback?
Negative feedback counteracts a stimulus to maintain stability, while positive feedback amplifies a stimulus to drive a process to rapid completion.
Explain why shivering increases body temperature and name the effector responsible for this response.
Shivering makes the muscles contract quickly, which produces heat. This extra heat helps warm the body back up and keeps internal temperature within a safe range. Effector= Skeletal muscle.
If the pancreas suddenly stopped producing insulin, what would happen to a person’s blood glucose levels, and why?
Blood glucose levels would rise too high because insulin is needed to help cells take in glucose from the blood. Without insulin, glucose stays in the bloodstream instead of being used for energy.
Explain how sensory, inter and motor neurons work together to cause a response.
Sensory neurons detect the stimulus and send a message to the spinal cord or brain. Interneurons process the information and decide what to do. Motor neurons carry the response message to muscles or glands so the body can react.