Homeostasis

1. Homeostasis of Metals
Presented by
Farjana Akter
ID: 22014002
Session: 2019-20
Department of Chemistry
Comilla University

2. Homeostasis
A state of balance
Ability to maintain
internal stability
Tendency to
maintain constant
internal
environment
Thermoregulation

3. Main Components
Receptor Control centre Effector
Detect changes Interpret the change Carry out the change

4. Feedback loops
Negative feedback loop
Tends to minimize the
effect of stimulus
Example: Production of
RBC by kidney when
decrease in oxygen senses
Positive feedback loop
Increase the effect of
stimulus
Example: Child Birth,
Rippening of fruit

5. Homeostasis
Imbalance
Imbalance
Receptor
Control
center
Effector
General Mechanism
Stimulus
Change
detected
Input sent Output sent
Response
opposes change

6. Metal Homeostasis
The ability of individual cells to maintain a healthy level of metals within the
cell.
Calcium homeostasis
Mechanism I
Sensor: Parathyroid gland
Effector: Bones, kidney
Mechanism II
Sensor: Thyroid gland
Effector: Bone

7. Calcium Homeostasis
Fall of Ca2+
Parathyroid gland(
chief cells) release
PTH
Osteoclast release from
bone
Ca2+ reabsorbed
Absorption in intestine
Release Ca2+
into plasma
Normal level of
Ca2+
Rise of Ca2+
Thyroid
glands(parafolicular
cell) release
calcitonin
Calcitonin
decrease the Ca2+
level
Mechanism I Mechanism II

8. Potassium
Homeostasis
High potassium concentration in
plasma
Depolarization of the zona
glomerolosa cells
Release of aldosteroneinto the blood
Aldosterone acts primarily on kidney
Excretion of potassium ions into the
urine
Activation of Na+/K+ pump 3Na+ out and
2 K+ into the cell
Ionic concentration
gradient produce
Reabsorption of sodium
(Na+) ions from the tubular
fluid into the blood
Secretion of K+ Ions
from the blood into
the urine

10. Copper regulation
Insufficient amount of Cu injected
Copper stores in the liver will be
depleted/ too much copper
Copper health deficiency/ Excess Copper
Injury and disease
Cu2+
Cu+

11. Metal homeostasis in bacteria
In bacteria , metal limitation activates pathways that are involved
in the import and mobilization of metals
Excess metals induce efflux and storage
Bacteria use sophisticated intercommunication systems to help
maintain their niches

12. Thank You