Download Lecture 5

Lecture 5:
Transportation, Role of
Hormones and the Nervous
System, and Digestive
Problems
Transportation
• How absorbed nutrients move around
the body
• What organs are involved in the
process of transportation
Nutrition 150
Shallin Busch, Ph.D.
Vascular (Blood) System
• Closed system of tubes
• Pumped by heart
• Transports most nutrients and fluids
Lymphatic System
• Collects fluid from outside of the
vascular system into lymph vessels
• Has no pump, but drains into vascular
system
• Transports most fats and fat-soluble
vitamins
The Vascular System
The Liver
Head and
upper
body
Capillaries
Hepatic vein
Liver: 500 functions!
Lungs
Pulmonary vein
Pulmonary artery
- Receives blood from
GI tract
Hepatic artery
Aorta
Right
side
Hepatic vein
- Filters wastes and
digests toxins
Left
side
Heart
Hepatic artery
Portal vein
Liver
Portal vein
Digestive
tract
Lymph
=
=
=
=
Arteries
Capillaries
Veins
Lymph vessels
Entire body
Autonomic Nervous System
• Nervous system that is not under voluntary
control
• Coordinates peristalsis, segmentation and
opening and closing of sphincters etc.
• Detects fullness of tract
• Detects presence of acidity, fats, proteins,
etc.
• Stimulates production within and/or
secretion by glands and cells
-Stores and releases
nutrients (glucose, fats,
amino acids)
Vessels
- Produces bile
Hormones
Hormone: A chemical messenger that is
secreted into the bloodstream by a
gland and effects physiological
processes at site remote from the
gland
Hormones coordinate many aspects of
digestion.
Hormones and Blood Sugar
Insulin: Hormone produced by pancreas.
Released when blood sugar is HIGH.
Causes cell membranes to increase
rate of glucose transport into cells.
Glucagon: Hormone produced by
pancreas. Released when blood sugar
is LOW. Causes breakdown of liver
glycogen into glucose, which is then
released into the blood.
Hunger
Hunger: A physiological sensation that
prompts us to eat. Coordinated in the
brain.
1) Change in pressure or fullness of stomach
and small intestine
2) Blood glucose level and the levels of the
hormones that control it (insulin and
glucagon)
3) Hormones neuropeptide Y and galanin
stimulate hunger
Appetite
Appetite: A psychological desire to consume
food. Controlled by the brain.
1) Perception of cues (smell, sight, sound, or
thought of tasty food)
2) Association with event
3) Emotional state
…brain causes releases of digestive enzymes
Satiation
1) High protein foods have highest satiety
value. High fat diets are more satiating
than high carb diets. Food is more satiating
than beverages.
2) Increased pressure on stomach and small
intestine
3) Hormones leptin, cholecystokinin, and
serotonin promote feelings of satiety
Peptic Ulcers
• “Area of the GI tract that
has been eroded away by the
acidic gastric juices of the stomach”
(Thompson and Manore)
• Helicobacter pylori infection
• Use of nonsteroidal anti-inflammatories
such as aspirin, ibuprofen, and naproxen
sodium
• Causes pain and bleeding (which can lead to
anemia).
Constipation
• Absence of bowel movements at
normal rate. Stools that are small,
hard, and difficult to pass
• Causes: Disorder of nervous system;
change in diet, schedule, medication;
dehydration; inadequate fiber
• Risk: Pain, hemorrhoids
Diarrhea
• Frequent passage of loose watery
stools
• Causes: infection, chronic disease,
bowel disorder, stress, food
intolerance, reaction to medicine
• Risks: Dehydration, loss of salts
Irritable Bowel Syndrome
• Symptoms: cramps, bloating, constipation or
diarrhea
• 20% of US population (more common in
women)
• No known cause, but linked to stress, caffeine,
chocolate, wheat, alcohol, dairy, large meals,
some medicine, immune response, female
reproductive hormones, etc.
• Treating symptoms and avoiding triggers,
stress management, physical activity, small
meals, high fiber diet, adequate water intake
Gas
Intestinal: Caused by digestion of food
by bacteria in large intestine. Can be
caused by ingestion of some food
(carb rich) and also by a change in
diet.
Belching: Typically from swallowing air
when eating. Eating too quickly,
carbonated beverages, ill-fitting
dentures, chewing gum