Download APThyroidRegulation

Thyroid Gland
An introduction to regulation of metabolism and the use
of isotopes in medical diagnosis
AP Big Idea #2 Homeostasis
Can you diagnose this
patient?
Thyroid Gland
• Structure of the thyroid gland
• Structure of the thyroid hormones
• Regulation of thyroid hormones (Examples of
feedback to maintain homeostasis)
• Pathology: What happens when control is off?
how are isotopes used to determine thyroid
function?
Structure of the Thyroid
Gland
What is a gland?
• “A group of special cells that make
substances so that other parts of the body
can work.
• Ex:
• Gland=pancreas: releases insulin; insulin
travels to cells so they can use energy
Other Glands of the Endocrine System
Endocrine System:
System of all the
hormone secreting cells
in an animal
Figure 45.5
What is a hormone?
• Chemical signal secreted into the body fluids
(blood) that regulate the activity of specific
target cells
Hormones involved with thyroid
control of metabolism
Gland
Hormones
Targets
Response
Thyroid
T4
Various Cells
Increased
metabolic
activity
Hypothalamus
TRH
“releasing”
Anterior
Pituitary
Activates
Pituitary
Anterior
Pituitary
TSH
“stimulating”
Thyroid
Activates
Thyroid
What is actually released
by the thyroid?
What elemental substance is needed to
catabolize (build) functional T4?
Goiter: Why do these
symptoms occur?
What are the targets of T3?
• T3 signals the following responses:
• Increase the rate of oxygen consumption
and cellular metabolism
• Maintain heart rate
• Normal blood pressure
• Muscle tone
• Digestion
• Reproduction
Mechanism of T3 & T4
• Enter cell membrane through transport
proteins
• Bind receptor in nucleus
• Alter gene expression
• What if this keeps on going and going and
going????
Mechanisms of Cell Signaling: Which mechanism would
T3 use (Fig 45.3)?
Control of Thyroid
Function
How goiter works?
Review Case Study
• Hyperthyroidism?
• Hypothyroidism?
• Homeostasis: Why is elevated TSH levels a
signal for thyroid malfunction?
What is an isotope?
• Can you remember this
from chemistry?
• Tracers: radioactive
isotopes can be ingested
and detected using a
variety of methods
• How can isotopes work as
tracers and help us make
medical diagnoses/study
living things?
How are isotopes used to
diagnose Graves or Goiter?
• RAUI (Radioactive iodine uptake)
• > baseline = Hyperthyroidism (Graves)
• < baseline =Hypothyroidism (Goiter)
Using Model Organisms to
Study Thyroid Function
On your own…
• Using Campbell’s Figure
45.9, determine how
feedback of calcitonin
and PTH maintain blood
calcium level.
Formative Assessment
• Can you define negative feedback and explain the
advantage of using a feedback system?
• Can you identify negative feedback in each of the
three systems we discussed?
• Thermoregulation
• Thyroid Regulation of Metabolism
• Calcium Regulation
• If given information about a person, can you
identify how the appropriate regulatory
mechanism is working in his/her body.