Chapter 9
Stage 3
Human Biological Science
Keywords
 Glucose
 Glycogen
Liver
 Glycogenesis
 Glycogenolysis
 Gluconeogenesis
Pancreas
 Islets of Langerhans
 Insulin
 Glucagon
Pituitary gland
 ACTH
Adrenal glands
 Cortisol
 Adrenaline
 Noradrenaline
Role of the liver
 We need glucose (from
the food we eat) for
cellular energy
 The liver plays a major
role in the control of
blood glucose levels
 The body cannot store
glucose, so the liver
converts it to glycogen
for storage
 When the body needs
glucose, glycogen is
converted back to glucose
for release into the blood
Glycogenesis
 The process of
converting glucose to
glycogen is called
glycogenesis
 This process is
stimulated by the
hormone insulin
 Glycogen itself cannot be
used by cells so it must
be converted back to
glucose for use
Glycogenolysis
 Glycogenolysis is the
process which converts
glycogen back to glucose
for use
 This process occurs
mostly between meals
 This process is
stimulated by the
hormone glucagon
Role of the pancreas
 The pancreas contains
hormone secreting cells
called the islets of
Langerhans
 There are 2 types of:
alpha cells and beta
cells
 Alpha cells secrete
glucagon
 Beta cells secrete insulin
Role of the pancreas
Insulin from the beta cells
causes a decrease in BGL by
accelerating:
1. the transport of glucose
from the blood into the
cells, especially skeletal
muscle cells
2. the conversion of glucose
into glycogen
Insulin can also
 Stimulate the conversion of
glucose into fat in adipose
tissue (fat storage tissue)
 Cause a increase in protein
synthesis in some cells
Role of the pancreas
Glucagon from the alpha
cells causes an increase
in BGL by stimulating
 the process of
glycogenolysis in the
liver
 the liver to produce
sugar molecules from
fats and amino acids, a
process called
gluconeogenesis
Glycogenesis
Reduced
level of blood
glucose
High blood
glucose
Beta cells
(pancreas)
Stimulus
Receptor
Beta cells
Secrete
insulin
Feedback
Response
 Glycogenesis
 Increased
glucose uptake
 Lipogenesis
Effector
 Liver
 Somatic cells
Glycogenolysis
Low blood
glucose
Increased
level of
blood glucose
Stimulus
Alpha cells
(pancreas)
Receptor
Alpha cells
Secrete
glucagon
Feedback
Response
 Glycogenolysis
Effector
 Liver
Role of the adrenal glands
The pituitary gland,
adrenal cortex and
adrenal medulla also
have a role in regulating
BGL
 Pituitary gland secretes
adrenocorticotrophic
hormone (ACTH)
 ACTH acts on the adrenal
glands. They secrete
glucocorticoids
(cortisol) which are
involved in
gluconeogenesis
The adrenal medulla
 The adrenal medulla
synthesis adrenaline
and noradrenaline
which act to stimulate
the breakdown of
glycogen in the liver and
the release of glucose
into the blood
Links
 http://bcs.whfreeman.com/thelifewire/content/chp50
/5002s.swf
 http://www.brown.edu/Courses/BI0020_Miller/week/
10/web-2/4-2-2007_10-2110/Chapter_41/Present/Animations/41_A02/41_A02s.h
tml
 http://www.mhhe.com/biosci/genbio/tlw3/eBridge/C
hp27/animations/ch27/1_glucose_regulation.swf
 http://outreach.mcb.harvard.edu/animations/homeos
tasis10.swf