Transcript Document

CHAPTER 41
ANIMAL NUTRITION
LEPTIN = apetite
suppressor (hormone
produced by fat cells)
The four main stages of food
processing are ingestion,
digestion, absorption, and
elimination
Why Eat?
C6H12O6 + 6O2 -> 6CO2 + 6H2O + Energy (ATP + heat)
 FUEL
BIOSYNTHESIS
 ESSENTIAL NUTRIENTS

Organic Macromolecules
ATP (Cell
Respiration)
Everything you eat gets
DIGESTED into glucose,
amino acids, and glycerol +
 FUEL
fatty acids
Why Eat?
These 
3 digestion
products
BIOSYNTHESIS
enter cell respiration
 ESSENTIAL
(glycolysis
and Kreb’s cycle) NUTRIENTS
Products of cell respiration –
CO2, NH3, H2O, ATP
 These end products can be
used for cellular work
(movement), generating heat,
and BIOSYNTHESIS
 Excess gets converted to
GLYCOGEN or FAT!
Organic Macromolecules
CO2, other simple
compounds
ATP
Why Eat?
Carbon Skeletons, and
other simple products of
cell respiration
ATP
FUEL
 BIOSYNTHESIS
 ESSENTIAL NUTRIENTS

BIOSYNTHESIS =
ANABOLIC
PATHWAY
Biosynthesis = Making of New Proteins,
Carbohydrates, Fats, Nucleic Acids needed by the
body using the energy and raw material derived from
food
How much energy do you get
from food?

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Carbohydrates – 4 kcal/gm
Proteins – 4 kcal/gm
Fats – 9 kcal/gm
Calorie = heat required to
raise the temperature of
water by 10c
Kcal = 1000cal
Cell Respiration = process
that “burns” food
Carbs = quick energy release
Fats, proteins = slow to
release energy
What happens to excess carbs?

Gets stored as glycogen
in liver and muscle
 Too much carb? -Gets
converted into fat!!!!
 Glycogen can be
released quickly during
exercise
 Disadvantge – less
energy (4 kcal/gm)
 Fats – more energy
(9kcal/gm), takes time to
release
How is glucose regulated?

Insulin (produced by
the Islets of
Langerhans - in
pancreas) =
decreases blood
sugar by ?
 Glucagon
(pancreas) =
increases blood
sugar by ?
2 places to find glucose - blood or cells; stored as glycogen
A) Glycogen synthesis in muscle and liver using free glucose in cells
How
is
glucose
regulated?
B) Glycogen breakdown to release glucose into the cells
C) Increased movement of glucose into blood from cells
D) Decreased movement of glucose into blood from cells
E) Increased uptake or movement of glucose from blood into cells
F) Decreased uptake or movement of glucose from blood into cells
G) Glucose utilization in cells - cell resp.
H) Glucose synthesis in cells

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Insulin (produced by the
Islets of Langerhans - in
pancreas) = decreases blood
sugar by A,D,E,G
Glucagon (pancreas) =
increases blood sugar by ?
B,D,F,H
Why Eat?
FUEL
 BIOSYNTHESIS
 ESSENTIAL NUTRIENTS

Essential nutrients – body cannot make it –
so, it must be provided preassembled in the
food. Example – Vitamins, essential amino
acids, essential fatty acids, minerals
+
=

An animal whose diet is missing one or
more essential nutrients is said to be
malnourished.
Animals require 20 amino acids to make
proteins.
 Essential amino acids must be obtained
from food in prefabricated form. (eight)

Protein Deficiency Kwashiorkar

Essential fatty acids.
– Certain unsaturated fatty acids, including
linoleic acids required by humans.
– Deficiencies are rare.
Mahatma Gandhi once said, "Where ever flaxseeds become a
regular food item among the people, there will be better health".

Vitamins -organic molecules required in the
diet in very small quantities (upto 100 mg)
Fat Soluble
Vitamins
Water Soluble
Vitamins
A, D, E, K
C, B, Niacin, Folic
acid, Biotin
Fat
Soluble
Vitamin
Function
Deficiency
A
Vision, maintain
healthy skin
Vision problems,
dry skin
D
Absorption of Calcium
and phosphorous =
helps bone growth
Rickets (bone
deformities)
E
Antioxidant – maintains
cell membrane
K
Blood clotting
Clotting problems,
Anemia
Water
Soluble
Vitamin
Function
C
Detoxification,
antioxidant, collagen
synthesis (gums)
Deficiency
Scurvy (skin,
teeth, blood
vessel
degenration)
B
Coenzyme component B1 – Beriberi
(1,2,6,12) –FAD, amino acid and (nerve disorder,
nucleic acid
anemia)
metabolism,

Minerals are simple inorganic nutrients,
usually required in small amounts - from
less than 1 mg to about 2,500 mg per day.
Mineral
Function
Calcium
Bone and tooth
Retarded growth,
formation, nerve and
osteoporosis
muscle function
Hemoglobin component Anemia
- cofactor
Iron
Sodium
Acid- base balance,
water balance, nerve
Deficiency
Too much – high
blood pressure
Feeder types:
– Herbivores- eat autotrophs (plants, algae).
– Carnivores - eat other animals.
– Omnivores – eat animal and plant/algal matter
Feeding mechanisms
– Suspension-feeders that sift small food
particles from the water.ex. Baleen whales, clam
Fig. 41.6

Substrate-feeders live in or on their food
source, eating their way through the food.
– For example, maggots burrow into animal
carcasses and leaf miners tunnel through the
interior of leaves.
Fig. 41.7

Deposit-feeders, like earthworms, eat their
way through dirt or sediments and extract
partially decayed organic material
consumed along with the soil or sediments.

Fluid-feeders make their living sucking
nutrient-rich fluids from a living host and
are often considered parasites.
– Mosquitoes and leaches suck blood from
animals.

Most animals are bulk-feeders that eat
relatively large pieces of food.
Fig. 41.9
Human Digestive System

Alimentary canal +
accessory glands that
secrete digestive juices into
the canal through ducts.
– Peristalsis: rhythmic wavespush food along.
– Sphincters: muscular ringlike
valves, regulate the passage
of food
– Accessory glands - salivary
glands, the pancreas, the
liver, and the gallbladder.
–When does the lunch you had
today complete its passage
through your digestive system?
• Mouth: Seconds
• Esophagus: Seconds
• Stomach: 2-6 hours
• Small Intestine: 5-6 hrs.
• Large Intestine: 12- 24 Hours
TOTAL = 19 – 36 hrs!!
Fig. 41.13
The journey begins ……
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Physical: chewing -Increases
surface area of food
Saliva - Moistens + Kills
bacteria + Buffer
Chemical digestion: Enzyme
Salivary Amylase – Acts on
“AMYLOSE” - long straings of
glucose found in
starch/glycogen
(starch + glycogen) -> (smaller
polysaccharides + maltose)

Pharynx (throat) - opens to esophagus
and the trachea (windpipe).
– Epiglottis - cartilaginous flap prevents food
going into the windpipe
Epiglottitis
Fig. 41.14
The stomach

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Muscular Organ – peristalisis chyme - mixture of gastric
juice+food
Gastric juice - glands
Parietal cells - HCl – pH 2!! kills bacteria; converts
pepsinogen -> pepsin
(inactive)->(active)
Chief cells - Pepsin – action =
proteins -> polypeptides +
amino acids
Mucous cells - Mucous
prevents eating away of
stomach lining
Pyloric Sphincterprevents back
flow of food!
Small intestine is the major organ
of digestion and absorption
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6 m long
First section – duodenum
LOTS OF ENZYMES FROM ACCESSORY
GLANDS
Pancreas makes – 1)pancreatic amylase
- acts on polysachcharides -> tri, di
saccharides; 2)bicarbonate - changes pH
to make it basic so enzymes can act on
the food; 3)trypsin, chymotrypsin - act
on polypeptides ->tri & dipeptides ,
4)lipase - acts on fats -> fatty acid and
glycerol, 5)nucleases act on DNA and
RNA -> nucleotides
Liver makes bile; gall bladder – stores
bile; bile emulsifies fats
Lining of intestine – other enzymes
(intestinal juice); convert to monomers

.
Fig. 41.18
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Jejunum, ileum – sections of small intestine
– absorption of nutrients into lymph/blood see notes in powerpoint slide for details
Active transport –glucose,
amino acid, vitamins
Passive transport - fructose
Hormones help regulate digestion
Hormones released by wall of the stomach
and duodenum
 Ensure that digestive secretions are present
only when needed.

– Stomach wall - hormone gastrin (stimulates
gastric juice)
– Duodenum – hormone Secritin (pancrease
releases bicarbonate)
– Duodenum – hormone Cholecystokinin (CCK)gallbladder releases bile
Reclaiming water is a major
function of the large intestine

Cecum- very mall in humans - appendix
Fig. 41.12
Fig. 41.12
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Structural adaptations of
digestive systems are often
associated with diet
(1)
Fig. 41.22