3 food_ feeding and digestion jan 2013

7/28/2019 3 Food_ Feeding and Digestion Jan 2013

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Topics

1. Introduction

2.Energy and thermodynamics

3.Feeding and digestion

4. Ionic gradient, electrical potential

5.Electrical signals and neurons

6.Cytoskeletons, motor proteins and muscle

7.Heat production and body temperature


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Teaching is transmission of knowledge

to students

Instruction Paradigm

Versus

Teaching is facilitation of studentslearning

Learning Paradigm


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Be an Active Listener

People speak at 100 to 175 words per minute,but they can listen intelligently at up to 300 words

per minute.

Mind-driftthinking about other things whilelistening to someone.

Listen with a purpose (gain info, obtain

directions, understand others, solve problems,share interests, show support)

Try repeating words mentally as they say it

control mind drift.


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Topics

1. Introduction








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Reading assignment

1. Visit the Open Door website on how animals feed:http://www.saburchill.com/chapters/chap0014.html

2. Visit the website on mad cow disease:

http://query.nytimes.com/gst/fullpage.html?res=9505EED7103BF9

35A35751C0A9629C8B63&sec=&spon=&pagewanted=1

3. Visit the website on space travel:http://library.thinkquest.org/03oct/01581/SpaceTravelEnglish/lifesupport/in

dex.html

4. Visit the website on eating disorder (and aestivation in lungfish)

http://www.swedauk.org/disorders/aes.htm
http://www.saburchill.com/chapters/chap0014.htmlhttp://query.nytimes.com/gst/fullpage.html?res=9505EED7103BF935A35751C0A9629C8B63&sec=&spon=&pagewanted=1http://query.nytimes.com/gst/fullpage.html?res=9505EED7103BF935A35751C0A9629C8B63&sec=&spon=&pagewanted=1http://library.thinkquest.org/03oct/01581/SpaceTravelEnglish/lifesupport/index.htmlhttp://library.thinkquest.org/03oct/01581/SpaceTravelEnglish/lifesupport/index.htmlhttp://www.swedauk.org/disorders/aes.htmhttp://www.swedauk.org/disorders/aes.htmhttp://library.thinkquest.org/03oct/01581/SpaceTravelEnglish/lifesupport/index.htmlhttp://library.thinkquest.org/03oct/01581/SpaceTravelEnglish/lifesupport/index.htmlhttp://query.nytimes.com/gst/fullpage.html?res=9505EED7103BF935A35751C0A9629C8B63&sec=&spon=&pagewanted=1http://query.nytimes.com/gst/fullpage.html?res=9505EED7103BF935A35751C0A9629C8B63&sec=&spon=&pagewanted=1http://www.saburchill.com/chapters/chap0014.html


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Solar energy/light

Chemical potential energy e.g. Na+ or K+ gradient

Chemical energy, ATP

Chemical energy, e.g. carbohydrate

Electrical energy, e.g. membrane potential

Heat

Heat

Heat

Heat


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Acquiring Energy: Feeding

Surface absorption

Filter feeding,

Fluid feeding and

seizing of prey


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Feeding Methods

Sessile animals: bottom

dwelling species commonly

resort to surface absorption,

filter feeding ortrapping

Mobile animals: follow a more

active sequence which in the

extreme case of many

carnivores includes searching,stalking, pouncing, capturing

and killing


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Surface Absorption

Food absorption from the surrounding environment

through exterior body surface

Many protozoans, endoparasites and aquatic

invertebrates

Take up nutrients e.g. amino acids by transportmechanisms

Take up large molecules by endocytosis

Endocytosis includes phagocytosis (extend outwards

and envelop relatively larger nutrient particles) or

pinocytosis (fold inwards and usually take up smaller

particles)


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TrypanosomiasisAfrican Sleeping sickness
http://www.sciencephoto.com/images/download_wm_image.html/M260285-Sleeping_sickness_blood_smear-SPL.jpg?id=772600285


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Tsetse flyGlossina sp.


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Surface absorption of

many substance

including tyrosin,tryptophan, and

phenylalanine, leading

to reduction in

transmitter substances

in the brain.


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Hepatosplenomegaly


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Beef tapewormTaeniasaginata


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Learning

Doing (experience)

Thinking

(reflection)

Information

Changes in

knowledge, skills,

attitude, value,

belief, etc.


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Solar energy/light

Chemical potential energy e.g. Na+ or K+ gradient

Chemical energy, ATP

Chemical energy, e.g. carbohydrate

Electrical energy, e.g. membrane potential

Heat

Heat

Heat

Heat


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Topics

1. Introduction








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Surface absorption

Filter feeding,

Fluid feeding and

seizing of prey


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Filter Feeding

Also called suspension feeding Use by many aquatic animals to capture food

especially phytoplanktons orzooplanktons

Most marine filter feeders are small sessile animals

e.g. sponges, brachiopods, bivalve mollusks, andtunicates

Food items are carried along on water current

(occur naturally or generated by the animal

movement or its external or internal flagella or cilia)

Tunicates

Sponges


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Filter feeding in sponges Water flow is generated by the activity of

flagellated choanocytes that line the flagellated chambers. Also flow is

brought about by the reduction in hydrostatic pressure at the osculum

due to the Bernoulli effect (a drop in fluid pressure as fluid velocity

increases).


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Food particles are phagocytosed by the flagellated

choanocyte and the amoebocyte

Digestion occurs in endocytic vacuoles


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Bivalve mollusks employ ciliary feeding


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The largest filter feeders is the

Baleen whales

Horny baleen plates in the mouth

bear a fringe of parallel filaments

of hair-like keratin that hangdown from the upper and lower

jaws and act as strainers

Whales swim with jaws open into

schools of crustaceans such as

krills, engulfing vast numberssuspended in tons of water.

As the jaw close, the water is

squeezed back out through the

baleen strainers with the help of

large tongue, and the

crustaceans left behind are

swallowed

Birds such as flamingos also use

filter feeding to capture small

animals found in the muddy

bottoms


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Surface absorption

Filter feeding,

Fluid feeding and

seizing of prey


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Fluid Feeding

Piercing and sucking occurs among platyhelminths,

nematodes, annelids and arthropods

Leeches are true bloodsuckers using an anticoagulant in their

saliva to prevent their preys blood from clotting

Arthropods that feed by piercing and sucking includes the

mosquitoes, fleas, bedbugs, and lice


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Fluid Feeding

Cutting and licking are used by numerous

invertebrates and a few vertebrates. The blackfly and related biting flies have mouthparts

with a sharpened mandible for cutting and a large,

spongelike labium for transferring the body fluid

(usually blood) to the esophagus. The cyclostomes (e.g. hagfishes and lampreys) use

rasplike mouths to make large, circular flesh wounds

on their hosts.

Vampire bats use their teeth to make puncturewounds in cattle from which they lick oozing blood.

Their saliva contain an analgesic to prevent the host

from feeling the effects of the bite.


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HookwormAncylostoma duodenale


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http://www.youtube.com/watch?v=Yhli5Otg8Q8&p=76AAA91627AA9A57

&playnext=1&index=1
http://www.youtube.com/watch?v=Yhli5Otg8Q8&p=76AAA91627AA9A57&playnext=1&index=1http://www.youtube.com/watch?v=Yhli5Otg8Q8&p=76AAA91627AA9A57&playnext=1&index=1http://www.youtube.com/watch?v=Yhli5Otg8Q8&p=76AAA91627AA9A57&playnext=1&index=1http://www.youtube.com/watch?v=Yhli5Otg8Q8&p=76AAA91627AA9A57&playnext=1&index=1


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Starfish
http://www.youtube.com/watch?v=BWOdssnzsMY&feature=related


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http://www.youtube.com/watch?v=BWOdssnzsMY&feature=related
http://www.youtube.com/watch?v=BWOdssnzsMY&feature=relatedhttp://www.youtube.com/watch?v=BWOdssnzsMY&feature=related


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Tube feethttp://www.youtube.com/watch?v=4IRF-pKVtuU&feature=related
http://www.youtube.com/watch?v=4IRF-pKVtuU&feature=relatedhttp://www.youtube.com/watch?v=4IRF-pKVtuU&feature=relatedhttp://www.youtube.com/watch?v=4IRF-pKVtuU&feature=relatedhttp://www.youtube.com/watch?v=4IRF-pKVtuU&feature=related


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Starfish eating a clam


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http://www.youtube.com/watch?v=rE8l-KFQlhY
http://www.youtube.com/watch?v=rE8l-KFQlhYhttp://www.youtube.com/watch?v=rE8l-KFQlhYhttp://www.youtube.com/watch?v=rE8l-KFQlhYhttp://www.youtube.com/watch?v=rE8l-KFQlhY


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Vampire bat


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A i i E F di


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Surface absorption

Filter feeding,

Fluid feeding and

seizing of prey

Siezing of Prey by Bulk Feeders


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Siezing of Prey by Bulk Feeders

Predators use various types

of mouthparts (jaws, teethand beaks) and other

appendages to capture and

process food.

Some use toxins toimmobilise the prey.

Their anterior limbs are

modified for prey capture


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Snake eating an egg

http://www.youtube.com/watch?v=LLk4rsCNFFU
http://www.youtube.com/watch?v=LLk4rsCNFFUhttp://www.youtube.com/watch?v=LLk4rsCNFFU


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Teeth of non-mammalian

vertebrates are usually non-

differentiated a single

tooth type is found

throughout the mouth

However, for the poisonous

snakes such as vipers,cobras and rattlesnakes

they have modified teeth

called fangs used for

injecting venoms.

Non-striking position (a) and striking position (b) of the

jaws of a rattlesnake


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For piercing and


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For gnawing in

rodents and rabbits

Modified into a pair oftusks in elephants

p g

tearing food by

carnivores,

insectivores and

primates Elongated as

tusks for prying

and fighting in

wild pigs and

walruses

Used for grinding

Molars of herbivores are coated intough enamels to resist wear

Alternatively, some herbivores

(rodents) have continuously

growing rootless teeth


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http://www.youtube.com/watch?v=uJyd1htGZhE&feature=related
http://www.youtube.com/watch?v=uJyd1htGZhE&feature=relatedhttp://www.youtube.com/watch?v=uJyd1htGZhE&feature=related


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Instead of teeth, birds have horny beaks, in a

multitude of shapes and sizes, adapted to

each species unique food sources andmethods of obtaining them.

Toxins


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Toxins Use to subdue preys or

fend off predators

Most toxins act at the

synapses in the nervous

system

The coelenterates fore.g. use nematocysts

Nematocysts are

stinging cells found on

the tentacles whichinject paralytic toxins

into prey and immobilise

it while the tentacles

carry it to the mouth


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Toxins


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Toxins Venoms are also used by annelids, gastropod molluscs and

cephalopods.

E.g. Blue-ringed octopus of the Indo-Pacific region, a tinycreature that kills a number of human every year.

Among the arthropods, scorpions and spiders are most

notorious for their toxins e.g in the case of scorpion, it

injects the poison containing a neurotoxin that interferes with

the proper firing of nerve impluses.

Spider poisons also contain neurotoxin e.g. the black widow

spider venom induces massive release of neurotransmitter at

the motor endplate of the victims muscles.

They must be carefully stored before administration toprevent self-poisoning.

They are generally proteins that are rendered harmless by

the proteolytic enzymes of the predators digestive system

when it ingests its poisoned prey.


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Topics

1. Introduction


3.Feeding and digestion4. Ionic gradient, electrical potential





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The alimentary system

and Digestion


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Digestive or alimentary systems

Play an essential role in nutrition by

digesting and absorbing food andremoving indigestible materials andtoxic by-products of digestion fromthe body.

Most primitive type is the plasmamembrane of unicellular organismswhich engulfs food particles byendocytosis. The food particles then

undergo intracellular digestion byenzymes or acids in food vacuolesbefore being absorbed into thecytoplasm.

Di ti li t t


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More complex multicellularorganisms rely primarily onextracellular digestion carried bytrue digestive system.

Can be categorised based onhow they process food.

Digestive or alimentary systems

1 Batched reactors


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blind tubes or cavities that

receive food and eliminatewastes in a pulsed fashion

i.e. one batch is processed

and eliminated before the

next one is brought in

E.g. of such type is found

in the coelenterates which

have a blind tube or cavity

called the coelenteron,

which opens only at a

mouth that serves double

duty as an anus for the

expulsion of undigested

waste.

1. Batched reactors

2 Contin o s flo stirred tank reactors


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2. Continuous-flow stirred tank reactors

A hollow tubular cavity that

open at both ends

Processing of food goes on

continuously rather than in

pulses with new food ingested

while older food is still beingprocessed

E.g. is the fore-stomach of

ruminants

3 Plug-Flow reactor


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3. Plug-Flow reactor

A bolus (a discrete plug) of

food is progressively digestedas it winds its way through a

long tube-like digestive

reactor

In contrast to the stirred tankreactor, the composition of the

food varies according to its

position along the reactor tube

E.g. Midgut or intestine ofvertebrate


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The alimentary canals of many animals

combine features of both continuous-flowand plug-flow reactors

In many animals, chemical digestion begins

in the stomach as a continuous-flow, stirred-tank reactorthen continues in the small

intestines as a plug-flow reactor


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Breakdown of cellulose in ruminants


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Breakdown of cellulose in ruminants Ruminants have multi-chambered digastric stomachs

Symbiotic microorganisms in the first division (rumen and

reticulum) of the stomach carry out fermentation

Partially digested food is regurgitated for remastication This

allows the ruminant to swallow food hastily and then chewed

it more thoroughly later when at rest in a place of relative

safety from predators

After the regurgitation, food is

chewed and swallowed again

Then it passes to the second

division where further

digestion takes place with the

help of digestive enzymes

secreted by the stomach

lining

Ruminant Stomach


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Copyright 2005 Pearson Education, Inc., publishing as Benjamin Cummings

Ruminant - Stomach


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The second division comprises the omasum and abomasum

(true stomach)

Rumen and reticulum fermentation

End-Products of fermentation accept for the gases are

absorbed together with some peptides, amino acids and

short chained fatty acids into the blood stream

The undigested material

then pass on to the omasum

and then the abomasum

Only the abomasum

secretes digestive enzymes

Cows and global warming


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Cows and global warming

http://www.time.com/time/world/article/0,8599,1890646,00.html
http://www.time.com/time/world/article/0,8599,1890646,00.htmlhttp://www.time.com/time/world/article/0,8599,1890646,00.html


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http://images.google.com/imgres?imgurl=http://www.cnsweb.org/digestvertebrates/GITFigures/ElephantAfricanGIT%2520F5_17f.gif&imgrefurl=http://www.cnsweb.org/digestvertebrates/WWWEdStevensMammalElephant.html&usg=__sXQWicIaaU_9TL0n88sXtaxAidA=&h=324&w=252&sz=7&hl=en&start=1&tbnid=DTdiXfAcvCIiVM:&tbnh=118&tbnw=92&prev=/images%3Fq%3Delephant%2Bdigestive%2Bsystem%26gbv%3D2%26hl%3Den


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B k d f ll l i hi d t f t


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Break down of cellulose in hindgut fermenters

The colon acts as a modified plug-flowreactorin most large animals (e.g. horses,

zebras, tapirs, elephants etc)

In smaller animals (rabbits, many rodents,howler monkeys, koalas etc), the

tremendously enlarged caecum acts as a

continuous flow, stirred tank reactor


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Quality of food greatly influences the time required for

digestion in a continuous-flow digestive reactor


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Transit time (mean retention time) of ingested material through

the vertebrate alimentary canal varies with body mass


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Transit time (mean retention time) of ingested material through

the vertebrate alimentary canal varies with body temperature


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Can animals live without food?

1.Symbiosis

2.Suspended animation

a. hibernation

b. aestivation

Life deep in the bottom of the sea the


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Life deep in the bottom of the seathe

hydrothermal vent

http://www.ocean.udel.edu/extreme2004/geology/hydrothermalvents/index.ht

ml#

A hydrothermal vent is a fissure in a planet's surface

from which geothermally heated water issues.

Hydrothermal vents are commonly found near

volcanically active places, areas where tectonic plates aremoving apart, ocean basins, and hotspots.

(Mars?)
http://www.ocean.udel.edu/extreme2004/geology/hydrothermalvents/index.htmlhttp://www.ocean.udel.edu/extreme2004/geology/hydrothermalvents/index.htmlhttp://www.ocean.udel.edu/extreme2004/geology/hydrothermalvents/index.htmlhttp://www.ocean.udel.edu/extreme2004/geology/hydrothermalvents/index.html


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ALVIN, an ONR-research submersible (a small submarine) operated by

Woods Hole Oceanographic Institute, made an amazing discover in

1977. While diving nearly 8,000 feet (2,400 meters) on the East Pacific

Rise near the Pacific Ocean's Galapagos Islands, the submersible and

its three passengers happened upon a hydrothermal vent, the first ever

seen by humans! Completely isolated from the world of light, wholecommunities oforganisms (creatures) live in places where warm water

flows from chimneys in the ocean floor. These vents are found in some

of the deepest places in the ocean, far beyond the reach of normal

submarines or divers.

http://www.youtube.com/watch?v=D69hGvCsWgA
http://www.onr.navy.mil/focus/ocean/vessels/submersibles1.htmhttp://www.onr.navy.mil/focus/ocean/vessels/submersibles1.htmhttp://www.youtube.com/watch?v=D69hGvCsWgAhttp://www.youtube.com/watch?v=D69hGvCsWgA


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Communities


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Some have biomass

1000 fold higher thannon-seep benthic

communities at same depth


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Molluscs


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Bathymodiolus thermophilus

methanotrophic bacteria

Calyptogena magnifica

thiotrophic bacteria

Hydrothermal vent mollusc bacterial symbiosis


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e.g. Calyptogena

Light-Enhanced Calcification in the Giant

Cl T id


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Clam, Tridacna squamosa

Found in inter-tidal zone.

Symbiotic relationship with photosynthetic zooxanthellae.


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Lack of food, hypoxia, desiccation

and temperature extremes

a. Hibernation

b. Aestivation


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Hibernation-Low temperature,


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fasting (disuse muscle atrophy???)


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African lungfish

Aestivation-high temperature, arid, fasting


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g p g

http://www.youtube.com/watch?v=ZUsARF-CBcI
http://www.youtube.com/watch?v=ZUsARF-CBcIhttp://www.youtube.com/watch?v=ZUsARF-CBcIhttp://www.youtube.com/watch?v=ZUsARF-CBcIhttp://www.youtube.com/watch?v=ZUsARF-CBcI


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Suspended animation--Application to


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space travel?

Suspended animation--Application to


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space travel?

Space Station astronauts share a

meal of canned goods during a recent

crew exchange aboard the ISS.


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The end

3 food_ feeding and digestion jan 2013

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