Body System Functions
What is the main function of the nervous system?
Coordination/regulation; receive and interpret information about changes in the internal and external environment (stimuli) and coordinate the body's responses
What is the function of the digestive system?
Digestion; take in and break down food into nutrients small enough to travel to and be used by cells
Which organ regulates blood sugar levels?
The pancreas
What is homeostasis?
The body's ability to maintain a stable internal environment (balance) despite changes in the external environment
What happens to blood vessels when body temperature rises?
Blood vessels dilate, allowing heat to be lost to the environment
What is the function of the respiratory system?
Respiration; take in oxygen needed by cells to release ATP
What does the digestive system break complex carbohydrates (like starch) into?
Simple carbohydrates / glucose
What hormone is released when blood glucose levels rise, and which cells release it?
Insulin; released by beta cells in the pancreas
In a homeostasis feedback loop, what is a "stimulus"?
A change in a variable that disrupts balance and triggers a response
What do sweat glands do when body temperature rises, and how does this cool the body?
Sweat glands secrete fluid. As the fluid evaporates, heat is lost from the body.
What does the circulatory system transport around the body? Name at least four substances.
Glucose, oxygen, carbon dioxide, hormones, water, wastes (any four)
What does the digestive system break proteins into?
Amino acids
After insulin is released, what do the liver and body cells do with glucose?
Body cells take up glucose; the liver takes up glucose and stores it as glycogen causing blood glucose to decline
In a homeostasis feedback loop, what does the "receptor" do?
Detects the change (stimulus) in the variable
What happens to blood vessels when body temperature falls?
Blood vessels constrict so that heat is conserved
Which body system would detect a sudden change in temperature outside your body and coordinate your response?
The nervous system; it detects stimuli and coordinates the body's responses
What does the digestive system break fats into?
Glycerol and fatty acids
What hormone is released when blood glucose levels fall, and what does it cause the liver to do?
Glucagon; released by alpha cells in the pancreas. It causes the liver to break down glycogen and release glucose into the blood.
What is the role of the "control center" in a homeostasis feedback loop?
Receives information from the receptor and sends output instructions along the efferent pathway to the effector
What is shivering, and why does it help when you are cold?
Shivering is the involuntary contraction of muscles. It generates heat, which warms the body.
A student is running a race. Which two body systems work together most directly to deliver oxygen to muscle cells?
The respiratory system (brings in O₂) and the circulatory system (transports O₂ to cells)
What is the function of the excretory system, and what would happen if it stopped working?
Excretion; removes wastes and toxins from the body. Without it, toxic waste would build up and cells could not survive.
The normal blood glucose set point is 90 mg/100 mL. A student eats a large meal. Trace the full homeostatic feedback loop that returns blood glucose to normal.
Stimulus: blood glucose rises → Pancreas (beta cells) release insulin → Body cells take up glucose; liver stores it as glycogen → Blood glucose declines back to ~90 mg/100 mL
What is an "effector" in a homeostasis feedback loop, and what does its response do to the original stimulus?
The effector carries out the response. Its response feeds back to influence the stimulus and return the variable to homeostasis (balance).
Which part of the brain regulates body temperature and osmotic pressure?
The hypothalamus