Download homeostasis worksheet

Name: ____________________________
Date: __________
Hour: ________
State whether each of the following indicates negative or positive feedback:
1. ________________________________ If blood temperature rises too high, specialized
neurons in the hypothalamus of the brain sense the change. These neurons signal other nerve
centers, which in turn send signals to the blood vessels of the skin. As these blood vessels dilate,
more blood flows close to the body surface and excess heat radiates from the body.
2. ________________________________ If the blood temperature falls too low, specialized
neurons in the hypothalamus of the brain sense the change and signals are sent to the cutaneous
arteries (those supplying the skin) to constrict them. Warm blood is then retained deeper in the
body and less heat is lost from the surface.
3. ________________________________ Part of the complex biochemical pathway of blood
clotting is the production of an enzyme that forms the matrix of the blood clot. This has a selfcatalytic, or self-accelerating effect, so that once the clotting process begins, it runs faster and
faster until, ideally, bleeding stops.
4. ________________________________ During childbirth stretching of the uterus triggers the
secretion of the hormone oxytocin, which stimulates uterine contractions and speeds up labor.
1.
Answer the following questions about maintaining body temperature.
Body temperature is managed by the ……………………….. centre. This system is located in the
…………………….. and has ……………………….. that can sense the temperature in the
blood. The role of this centre is to maintain a constant …………………………. temperature by
balancing heat gain with heat loss. The vital organs located deep within the body, such as the
heart, liver and kidneys, are maintained at ………°C. This is called the …………………. body
temperature.
Core
37
Receptors
Hypothalamus
Body
Thermoregulatory
a. Complete the diagram below about how the body temperature is brought back to
normal. State two ways in which body temperature can be reduced and two ways in
which body temperature can be increased.
temperature increases
1. ……………………………………….
……………………………………….
2. ……………………………………….
normal body temperature
……………………………………….
normal body temperature
temperature decreases
1. ……………………………………….
……………………………………….
2. ……………………………………….
……………………………………….
3.
The concentration of glucose in the blood is also controlled by the body. Answer the
following questions.
a. Are the following statements true or false? Answer by circling T for true or F for false
in the space to the left of each statement.
T/F
The hypothalamus produces the hormone insulin.
T/F
Insulin allows glucose to move from the blood into the cells.
T/F
The pancreas produces a second hormone glucagon.
4. Fill in the blanks to show the process of negative feedback.
Effector
Balance
Receptor-Sensor
Stimulus
Control Center