Exam Quiz 7
1.
When fats and proteins are present in the duodenum, events occur that result in digestive enzymes
being released into the duodenum from the pancreas. In addition, the gall bladder contracts and
releases bile into the duodenum.
It is reasonable to conclude that
A. Signalling molecules carry messages from the duodenum to both the gall bladder and the
pancreas
B. Signalling molecules would diffuse through tissue fluid that dills the spaces between the
different organs
C. An increase in digestive enzymes from the pancreas will result in an increase of fats and
proteins in the duodenum
D. An increase in bile from the gall bladder reduces the breakdown of fats and proteins
2.
Homeostatic systems comprise components such as sensors, effectors and variables. In such
systems, the component being kept relatively constant is
A.
B.
C.
D.
The variable
Input to the senor
Input to the effectors
Output from the effectors
3.
A woman accidently touched a hot object. She withdrew her hand quickly in a reflex action. A model
of this event is best represented by:
4.
The following diagram represents the steps in blood clotting
Clotting
accelerates
Break in
blood
vessel wall
Damaged
cells release
chemicals
Clotting
cascade
begins
Loop Y
Additional
chemicals
released
Loop X
A.
B.
C.
D.
Feedback loop X is a positive feedback that lowers the original stimulus
Feedback loop Y is a positive feedback that hastens the formation of the blood clot
Feedback loop Y is a negative feedback that increases the production of chemicals
Feedback loops X and Y are both examples of homeostasis
Short Answer
Thyroid hormone, thyroxine is produced by the thyroid gland in the throat region. The following
diagram summaries the production and action of thyroxine in the body.
1.
a. How does TSH travel to the thyroid gland?
Blood clot
plugs vessel
wall
The system shown in the diagram above is called a negative feedback system.
b. Write a general statement that outlines the principle of a negative feedback system
The two diagrams shown below are general models for signal reception and transduction
c. i which model, model S or model T, best corresponds to the mechanism of TSH?
ii. Explain your choice
Testes and brain tissue do not respond to thyroxine.
d. what is the most likely explanation for this condition?
The following diagram shows some detail of a cell form a thyroid gland.
e. Name structure M
f. Name structure N
g. Name the process occurring at site P