Chapter 20: Unifying Concepts of Animal Structure and Function NEW AIM: How are animals organized?...

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Chapter 20: Unifying Concepts of Animal Structure and FunctionNEW AIM: How are animals organized?

Animal form and function (anatomy and physiology)

Anatomy

Physiology

- Structure of the organism

- Function of the organism

Structure determines Function

Anatomy and Physiology

Exchange with the environment

Fig. 20.1

Chapter 20: Unifying Concepts of Animal Structure and FunctionAIM: How are animals organized?

Tissue

- cooperative unit of cells with similar structure and function

Fig. 20.2

There are only 4 major types in animals:

Fig. 20.2

Tissue

1. Epithelial tissue

- Covers outside of body and lines the organs and cavities within the body like the GI tract, bladder, lungs, etc…

Fig. 20.4

Tissue

- Cells packed side by side and typically function as barrier against mechanical injury, pathogens and other microbes, fluid loss.

Fig. 20.4

Tissue

“Simple” = single layer of cells

“stratified” = many layer of cells

Two criteria for identifying type of epithelia:

1. Is it…

Fig. 20.4

Tissue

“cuboidal” = cube-shaped

“squamous” = flat like floor tiles

Two criteria for identifying type of epithelia:

2. Is it (shape)…

“columnar” = column shaped like bricks

Fig. 20.4

Tissue

Structure / Function

- Covers outside of body and lines the organs and cavities within the body like the GI tract

Tissue

Simple columnar

Simple cuboidal

Tissue :

4 major types in animals

1. Epithelial tissue2. Connective tissue

- Cells are sparse and scattered through an ECM like raisons in bread

- Cells produce ECM (raisons make the bread)

Fig. 20.5

- Serves to bind and support other tissue

Tissue :

1. Epithelial tissue2. Connective tissue

- Cells are sparse and scattered through an ECM like raisons in bread

- Cells produce ECM (raisons make the bread)

Tissue :

1. Epithelial tissue2. Connective tissue3. Muscle tissue

- made up of muscle fibers (cells)

- most abundant tissue type in animals

Fig. 20.6

- Cable of contraction – usually when stimulated by a nerve signal

Tissue :

1. Epithelial tissue2. Connective tissue3. Muscle tissue

- made up of muscle fibers (cells)

- most abundant tissue type in animals

Three types:1. Skeletal2. Smooth3. Cardiac

skeletal smooth cardiac

Tissue :

1. Epithelial tissue2. Connective tissue3. Muscle tissue4. Nervous tissue

- neuron = a single nerve cell (a single wire)- forms a rapid communication system- senses stimuli, processes and directs response

Fig. 20.7

Several tissues are organized to form an organ:

Fig. 20.8

Several tissues are organized to form an organ:

Organs cooperate to build organ systems:

Fig. 20.9Organ systems cooperate to complete the body…

Fig. 20.9

Function is to bring in chemicals (nutrients: monomers, fatty acids, glycerol, cholesterol, vitamins [used as coenzymes – organic cofactors], minerals [ions to be used as cofactors, neuron firing, etc…]) to your cells for building (biosynthesis), storing, or burning to generate ATP for building.

Fig. 20.9

Serves for gas exchange. Bring in molecular oxygen (O2) to your blood, which will be used to perform cell respiration by your cells. To get rid of (excrete) CO2 and H2O waste coming from cell respiration (CO2 released during grooming and Krebs, H2O formed at the end of the ETC from the reduction of O2).

Fig. 20.9

The heart pumps blood around your body in hollow tubes made of cell called arteries, veins, and capillaries (these would be the roadways of your body). EVERY cell is at most three cell lengths away from a capillary (from the blood supply). The system delivers nutrients and oxygen to all cells for building, burning or storing, and takes away the waste products that cells excrete like CO2 and urea (nitrogen waste from the deamination of amino acids). CO2 will be eliminated by the lungs (resp./excretory system) and the urea will be eliminated by the kidneys (excretory system). The blood also carries other substance like white blood cells (WBC’s).

Fig. 20.9

Cleans the blood of metabolic waste (waste from chemical reactions) like H2O from cell respiration, and urea from deamination. The kidney are “blood filters”, removing urea, excess salt or excess water and other undesirable chemicals from the blood. Although not shown, the respiratory system has excretory function in the elimination of CO2 since it is a gas along with the skin, which will release some urea, salt and water as sweat.

Fig. 20.9

Your cells must be able to talk to each other. For example, growth hormone coming from the pituitary gland in the brain instructs cells to undergo mitosis (bypass the G1 checkpoint) or insulin from the pancreas instructing the liver to take up glucose from the blood.

What you must realize, however, is that no one cell knows what all other cells are doing. They are mechanical and respond to internal and external signals. It is analogous to our society. There is no one person that knows what all people are doing. I communicate with certain people and they communicate with others etc… and in the end all people are connected/networked.

CELLS TALK…

Fig. 20.9

Your cells must be able to talk to each other. For example, growth hormone coming from the pituitary gland in the brain instructs cells to undergo mitosis (bypass the G1 checkpoint) or insulin from the pancreas instructing the liver to take up glucose from the blood.

The endocrine system uses hormones (chemicals: steroids, amino acids, polypeptides, proteins) put into the blood by endocrine cells, which bind to and signal others cells to perform certain functions. This system is typically slow and long term – takes a while for the hormones to circulate and they will stay around a while…

Fig. 20.9

The nervous system is also all about cellular communication, but instead of using chemicals released into the blood, it uses cells that act like wires called neurons that transmit electrical signals. These signals are extremely fast (up to 120 m/s) and are typically short lived. An example would be moving your finger or any other skeletal muscle. The electrical signal is sent from your brain, down your spinal cord and out to the muscle in your finger.

Fig. 20.9

There are millions upon millions of bacteria, fungi, parasitic worms, etc… that would love nothing than to take your organic molecules and make them lunch. Luckily you have an immune and lymphatic system. These systems work together to clear your body of foreign substance. White blood cells are responsible for the destruction of these substances. They, like all blood cells, are born in the bone marrow and serve to protect…

Fig. 20.9

What is life without a reproductive system? Nonexistent. This one if fairly self-explanatory. It is also the only system not required for the organism itself to survive.

Fig. 20.9

The muscular system is composed of all the skeletal muscles of the body. The skeletal muscles allow the body to move when combined with signals from the nervous system (and a lot of ATP of course)

Fig. 20.9

The skeletal system serves to support the body (without it you would be a blob on the floor), protects vital organs like your lungs, brain, spinal cord and heart, and contains marrow that produces blood cells.

The integumentary system is composed of the skin, hair and nails (feathers and scales), all of which are mostly non-living. This system serves to waterproof, cushion and protect the deeper tissues, excrete wastes, regulate temperature, is the attachment site for sensory receptors to detect pain, sensation, pressure and temperature, and may attract a mate. In humans the integumentary system additionally provides vitamin D synthesis.

Integere means “to cover” (latin)

Fig. 20.9Organ systems cooperate to complete the body…

Chapter 21: Nutrition and Digestion

Nutrition and The Digestive System

NEW AIM: How do animals obtain nutrition?

1. Filter (suspension) feeder 2. Substrate Feeder

3. Fluid Feeder 4. Bulk Feeder

Four Types of ANIMAL ingestion:

NEW AIM: How do animals obtain nutrition?

Chapter 21: Nutrition and DigestionAIM: How do animals obtain nutrition?

macromolecules too large to cross plasma membrane

animals need monomers to make their polymersREASONS:

AIM: How do animals obtain nutrition?

What will the nutrients be used for?

(EGESTION)

Let’s now look at organisms form simple to more complex and see how they perform nutrition.

Digestion must be contained in specialized compartments:

1. Digestion occurs in individual cells.

Single celled organisms:

A. Phagocytose and fuse lysosomes with the resulting food vacuole

Sponges

1. Digestion occurs in individual cells – can only eat detritus.

Phylum: Porifera

Fig. 21.3A

2. Gastrovascular cavity – allows organism to eat larger pieces of food- Digestion (gastro) and circulation (vascular) of nutrients to body; only one opening

Hydra:

Phylum: Cnidaria(Coelentrates)

- Cells lining GV cavity secrete hydrolytic enzyme onto the ingested food to chemically break it down (food its trapped in the cavity and circulated by flagella) and then phagocytose the remaining pieces to be further broken down by lysosomes.

Cnidocytes (stinger cells)- cell after which the phylum is named

- found on surface of tentacles

Chironex fleckeri (“Box jellyfish”)

- each cell contains a coiled thread with a capsule (nematocyst)

- when triggered, coil shoots out and wraps around/stings prey

Chapter 21: Nutrition and DigestionAIM: How do animals obtain nutrition?Cnidarians

Platyhelminthes also uses a GV cavity

SYMMETRY

No symmetry Central axis where several cuts can be made through axis to make many equal pieces (like a pizza pie).

Only one plane can be cut to divide the organism into two equal halves.

- A tube beginning with the mouth and ending with the anus having specializations along the way for ingestion, digestion, absorption and egestion.

Fig. 21.3B

- All the remaining phyla (nematode to chordata) use an AC

3. Alimentary canal (AC)

1. Substrate feeders taking in soil through the mouth

Phylum: Annelida

Fig. 21.3B

2. Soil enters pharynx (throat) and then passes down the esophagus to the crop.3. The crop is an organ that moistens and stores food as the organism can eat soil quicker than it can digest and absorb the organic material.

Phylum: Annelida

Fig. 21.3B

4. The crop will slowly release food into the gizzard, which contains a bit of sand and serves to grind the food (mechanical digestion) like we do in our mouth to increase surface area for the upcoming chemical digestion.

5. The pulverized material then enters the intestines where enzymes will be secreted into the canal to chemically breakdown the food (hydrolysis of polymers).

Phylum: Annelida

Fig. 21.3B

6. The intestines is also the site of absorption of monomers into the blood.

7. The undigested material is egested through the anus.

Phylum: Arthropoda

AIM: How do animals obtain nutrition?3. Alimentary canal (AC)

1. Similar to Annelids2. Bulk feeder, food ingested through mouth, passes down esophagus into a crop and then into a gizzard.3. The gizzard of insects can have hard teeth-like appendages for grinding the food.

Phylum: Arthropoda

4. Food then enters the stomach where enzymes are secreted by cells onto the food resulting in chemical digestion.

6. Gastric pouches are extensions of the stomach, increasing surface area to aid in absorption of nutrients into the haemolymph (“blood of the open circ. system”).

5. The stomach is ALSO the site of absorption

Phylum: Arthropoda

7. The intestine is short and mainly used for water absorption.

8. Undigested food is eliminated through the anus.

Phylum: Chordata

1. Bulk feeder, food ingested via mouth (no teeth, save on weight) and passes down esophagus into crop.2. Food is then slowly released into the stomach where some chemical digestion of proteins begin and a bit of mechanical digestion occurs.

3. Partially digested food then enters the gizzard to be mechanically digested.

Crop full with food

Phylum: Chordata

4. Many birds will eat stones, which will get caught in the gizzard and aid in the grinding of the food to increase the surface area.

5. Food will then be passed back to the stomach for more chemical digestion now that there is more surface area and then back to the gizzard. The food will go back and forth a number of times before moving into the small intestines.

Crop full with food

Phylum: Chordata

6. In the small intestines, the majority of the chemical digestion occurs followed by absorption of nutrients into the blood.

7. Food then enters the large intestines where water and electrolytes (ions like Na+, K+, Cl-, Mg++, etc…) are absorbed.

Crop full with food

8. Undigested material is egested via anus.

The Human Digestive System

Spincters- Rings of muscle that close off tubes

1. The Mouth

Fig. 21.5a. Digestion Begins

i. Salivary Glands and saliva

- Slippery glycoprotein

- Buffers- Antibacterial compounds (antibodies - IgA)

- 98% water

- Salivary amylase

ii. Chewing

- easier to swallow- increase surface area- Types of teeth

Mechanical Digestion

Chemical digestion

iii. Tongue- bolus

Salivary amylase

Salivary amylase is an enzyme that catalyzes the hydrolysis of starch and glycogen in the mouth.

Prefix (Amyl-) - Starch

Suffix (-ase) - Enzyme

Main products are small polysaccharides and disaccharides

Calcium cofactor

2. The Pharynx

Fig. 21.6

a. the swallowing reflex

2. The Pharynx

Fig. 21.6

a. the swallowing reflex- larynx moves up and epiglottis (elastic cartilage) swings down to cover trachea

- esophageal sphincter loosens up

2. The Pharynx

Fig. 21.6

a. the swallowing reflex- larynx moves up and epiglottis swings down to cover trachea- esophageal sphincter loosens up

3. The Esophagus

Fig. 21.7

a. peristalsis- circular muscle layer - contracts to push food down- longitudinal muscle layer - contracts to shorten esophagus

- 5 to 6 seconds to get to stomach

**Entire digestive tract (alimentary canal, Gastrointestinal tract, GI tract) is wrapped in smooth muscle for peristalsis

4. The Stomach

Fig. 21.8

a. Holds 2 liters of food/drink (storage)b. Pinched off by sphincters on either end – cardiac orifice (lower esophageal sphincter – not a true sphincter, not shown) and pyloric sphincter

Fig. 21.8

4. The Stomachc. Surface highly folded

-Allows for expansion -Gastric Distension-(distention – an enlargement or ballooning effect)

Rugae (rugal folds)

Fig. 21.8

i. tubular gastric glands (pits) line rugal folds

- 3 cell types in pits

1. Parietal cells

2. Chief cells

- Secrete HCl (hydrochloric acid) – pH of stomach is ~2 to 3, which will denature proteins and expose their peptide bonds to proteolytic (protein digesting) enzymes.

- Secretes the proenzyme (an inactive enzyme – aka zymogen) called pepsinogen

Fig. 21.8

i. tubular gastric glands

- 3 cell types3. Mucous cells

- secrete mucus (slippery glycoproteins and other substances) to protect the stomach epithelial lining from the gastric juices.

Fig. 21.8

i. tubular gastric glands

- 3 cell types1. Mucous cells2. Parietal cells3. Chief cells

Secretions = gastric juice

Fig. 21.8

4. The Stomachd. Pepsinogen activation

1. Activated first by low pH – low pH causes conformational change in pepsinogen resulting in autocatalysis (it cuts itself removing green polypeptide – see above) to become pepsin

(positive feedback)

2. Pepsin i protease (performs proteolysis – the hydrolysis of protein)

- enzyme that hydrolyzes proteinsii. Begins protein digestion in stomachiii. Pepsin cleaves/activates other pepsinogens

pepsinogen

pepsin

or pepsin

Fig. 21.8

4. The Stomache. Gastric glands OFF by default

1,2) See, smell, taste food sends nerve signal to initially activate glands3,4) Food in stomach activates cells to secrete hormone gastrin into blood

- gastrin binds to gland cells and keeps them active (increase HCl output)

- low pH inhibits gastrin release (negative feedback)5) Food is gone, glands are off

Gastrin – Small peptide

***All hormones are either steroids or amino acid based (modified amino acids, polypeptides, proteins)

4. The Stomachf. Mechanical digestion

i. smooth muscle contracts to churnii acid chyme

- churned food + gastric juices- squirted into duodenum of small intestines- 2-6 hours to empty stomach

5. The Small Intestinesa. 6 meters long, 2.5 cm diameter

b. Major site of chemical digestion

b. Major site of chemical digestionc. Aided by Liver/Gall Bladder and Pancreas

i. Liveri. Produces bile

-contains bile salts (amphiphilic)- (steroid acids)

Taurocholic acidGlycocholic acid

- contains bile salts

Taurocholic acidGlycocholic acid- emulsifies fat

emulsification is NOT chemical digestion. It is mechanical. These acids break apart large collections of fat molecules into small, soluble collections of fat molecules. NO covalent bonds have been broken here!!!

- Increases surface area for chemical digestion

- emulsifies fat

emulsification is NOT chemical digestion. It is mechanical. These acids break apart large collections of fat molecules into small, soluble collections of fat molecules. NO covalent bonds have been broken here!!!

ii. Gallbladder- stores and concentrates bile (up to 60 ml) made by liver

- emulsifies fat

Fig. 41.19

ii. Gallbladder- stores and concentrates bile (up to 60 ml)

- emulsifies fat

Fig. 21.10A

Gallstones - 80% are cholesterol stones (green in color)

Caused by too much cholesterol and not enough bile salts in gall bladder

iii. Why is fecal material brown?-The brown color comes a combination of bile and a compound called bilirubin, -What is bilirubin?-The liver breaks down excess heme (hemoglobin cofactor) and bilirubin is a yellow breakdown product of heme – brown in high concentration.- bilirubin is also in urine giving it its yellow color

Fig. 21.10A

bilirubin

- Bilirubin is also the cause of yellowing around bruises and the yellowing in jaundice indicating potential liver disease (hepatitis – viral), liver cancer, obstruction of biliary tract by gallstones, poor kidney function, etc...

Jaundice - Look at the yellowing of the eyes…caused by too much bilirubin in the blood.

iii. Why is fecal material brown?

iii. Pancreas (its exocrine function)i. Produces digestive enzymes

-Trypsin

Fig. 21.10A

- Chymotrypsin

chymotrypsin

endopeptidases

Exocrine gland Gland (cells) that secrete their products into a duct (tube) that leads outside the body

iii. Pancreasi. Produces digestive enzymes

-Trypsin- Chymotrypsin

chymotrypsin

Trypsin and chymotrypsin, like most digestive enzymes, are made as proenzymes (zymogens) and are activated after secretion. The proenzymes are called chymotrypsinogen and trypsinogen

- Carboxypeptidase

- This enzyme is an exopeptidase meaning it hydrolyzes polypeptides from the ends. In this case the C-terminal end…hence its name.

Carboxypeptidase

- Pancreatic Lipase

- Carboxypeptidase

- Pancreatic Lipase- Pancreatic Amylase- Ribonuclease- DeoxyRibonuclease

- Carboxypeptidase

iv. Duodenum- first 25 cm of small intestines- acid chyme meets bile, pancreatic enzymes, enzymes from intestine wall (maltase, aminopeptidase (exopeptidase), dipeptidase, sucrase, lactase)

- all macromolecules digested

iv. Duodenum

Carbohydrates- pancreatic amylase- maltase, sucrase, lactase

iv. Duodenum

Proteins (proteases)- trypsin, chymotrypsin- aminopeptidase, carboxypeptidase

- dipeptidase(work together as a team)

iv. Duodenum

Nucleic acids (nucleases)- ribonuclease- deoxyribonuclease

iv. Duodenum

Fats- lipase with the help of bile salts

Mechanical digestion

Chemical digestion (hydrolysis)

Hormonal Control of Digestion

1. Gastrin

2. Secretin

3. CCK (cholecystokinin)

4. Enterogastrone

- Secreted by stomach when food present. Circulates in blood and binds receptors on stomach cells stimulating production of gastric juice.

- Hormones are chemicals secreted into BLOOD that circulate and bind receptors on target organs

- Secreted into blood by duodenum when acid chyme present. Target organ is pancreas. Stims pancrease to secrete sodium bicarbonate (a base – baking soda – Na+HCO3-) to neutralize acid chyme.

- Secreted into blood by duodenum when acid chyme present. Target organs are gall bladder and pancreas stimulating release of bile and dig. Enzymes, respectively.

- Secreted into blood by duodenum when acid chyme present. Inhibits gastric secretion and peristalsis in stomach to slow down digestion when chyme rich in fats enters duodenum (takes longer to break down fat so you need to slow down the stomach)

iv. The remainder of small intestines

Jejunum- Middle section of small intestines (2.5m long)

- Absorption of almost all nutrients (monomer, vitamins, minerals)

- Huge surface area 300m2 (tennis court) due to:

Fig. 21.10B

- Large folds and projections that contain villi- Villi are individual folds produced by many cells each containing microvilli.

- Microvilli – folds of membranes of individual cells

Jejunum

iv. The remainder of small intestinesFig. 21.10B

- blood vessels and lymph vessels (lacteals) penetrate villi- Nutrients diffuse (facilitated if hydrophilic, simple if hydrophobic and small) or are actively transported into blood.

- Nutrients go first to liver, then heart and rest of body

JejunumWhere are all these nutrients going?

- Lipids will enter the lacteals, other nutrients enter blood

- Micelles of fatty acids, monoglycerides and bile salts diffuse through epithelial lining into lacteals – lymph system – which will eventually drain into blood near heart.

- Nutrients go first to liver (the gatekeeper), then heart and rest of body

- Liver removes many of the absorbed nutrientsA. Glucose and other monnosaccharides are removed and converted to glycogen

B. Excess amino acids are removed and deaminated- Amino group converted to urea (urea will be excreted in urine) and the rest can be burned or used for biosynthesis

- Nutrients go first to liver, then heart and rest of body

- Liver removes many of the absorbed nutrientsC. Many toxins like ethanol are removed and converted to a non-toxic form

Hepatic Portal System

You can see the veins wrapping stomach, small intestines and large intestines – all blood goes to liver via hepatic portal vein.

ileum- Final section of small intestines

A. Absorb Vitamin B12 (cobalamin)

ileum- Final section of small intestines

Vitamin B12

B. Absorb bile salts

a. 1.5 meters long, 5 cm diameter

b. Sphincter controls entrance (ileocecal valve)c. Cecum/Appendix

d. Function- absorb water, salts and some vitamins- 7 liters enter alimentary canal/day

Fig. 21.11

- 90% absorbed by Small intestines

- rest absorbed by large intestinese. peristalsisf. Too little water absorbed = diarrheag. Too much water absorbed (peristalsis too slow) = constipation

h. Recum (store feces) / anus – double sphincter

6. The Large Intestines (cecum, colon and rectum)

Fig. 21.11

i. Bacteria in the colon (gut flora)

- Break down some of the fiber (cellulose) and release waste products that your cells can use…

- Produce vitamins like biotin (used by the “grooming” enzymes), folic acid, several B vitamins and vitamin K (needed for blood clotting).

- 99% are anaerobes

- Make up 60% of the dry mass of feces

- ~500 different species including E. coli.

- One of the causes of flatulance

- Mutualism

j. cecum

- The cecum of herbivores tends to be much larger than that of carnivores

- Filled with bacteria to break down plant material.

ULCERS

How is the wall of the stomach protected from gastric juice?

Gastric (stomach) Ulcers - occur when the mucous protection fails

Symptoms

- pain in upper abdomen several hours after eating

ULCERS

Gastric Ulcers - occur when the mucous protection fails

Symptoms

Helicobacter pylori

What would you hypothesize is the reason people get gastric ulcers?

ULCERS

Gastric Ulcers - occur when the mucous protection fails

Symptoms

Helicobacter pylori

- spiral bacterium- can survive low pH of stomach- attaches to lining and secretes neutralizing chemicals- mucous lining breaks down in region of infection- gastric juice now kills stomach cells quicker than mitosis can replace them

What would you hypothesize is the reason people get gastric ulcers?

VEGETARIANS

Can people get all the nutrients they need without eating animal products?

Essential amino acids - humans CAN’T make 8 of the 20 amino acids

Simplest way to get all the nutrients?

Eat meat and animal by-products - eggs, cheese and milk

- Complete proteins (have all amino acids)

VEGETARIANS

Can people get all the nutrients they need without eat animal products?

Essential amino acids - humans CAN’T make 8 of the 20 amino acids

Simplest way to get all the nutrients?

Eat meat and animal by-products - eggs, cheese and milk

- Complete proteins (have all amino acids)

Vegetarians MUST eat a variety of plant foods that collectively supply the essential amino acids

Ex. Beans + corn

- Incomplete proteins

Most plant proteins are deficient in one or more amino acids

Fig. 21.16

VITAMINS

- most are coenzymes

ESSENTIAL VITAMINS

- most are coenzymes

- 13 vitamins are essential

Table - Page 445

NON-ESSENTIAL VITAMINS

Table - Page 445

Nearly all vitamins are considered essential.

Vitamin D, which is important for calcium absorption and the maintenance of bone tissue, is synthesized by skin cells following exposure to ultraviolet B radiation from sunlight.

Vitamin K and Biotin are synthesized by the gastrointestinal bacteria that constitute your gut flora.

MINERALS (ALL ESSENTIAL)

- chemical elements other than C,H,O,N

- must be obtained in our diets

Table - Page 446

ESSENTIAL FATTY ACIDS (ALA [ω-3] and LA [ω-6])

Both polyunsaturated fats

Food with high levels of these - fish and shellfish, flaxseed (linseed), hemp oil, soya oil, canola (rapeseed) oil, chia seeds, pumpkin seeds, sunflower seeds, leafy vegetables, and walnuts.

These polyunsaturated fatty acids (ALA and LA) are necessary to synthesize other fatty acids used to build phospholipids for cell membranes of your cells…

REVIEWI. Nutrition

- ingestion, digestion, absorption, egestion (elimination)- individual cells (porifera)- Gastrovascular cavity (Cnidarians)

- Alimentary Canal (Arthropods, Annelids, Chordates)

Mouth -> pharynx -> esophagus -> crop, gizzard, stomach -> intestines -> anus

REVIEW

II. Humans

Mouth- Mechanical and chemical digestion (saliva/chewing)

Swallowing reflexEsophagus (peristalsis)Stomach

- Mechanical and chemical digestionSmall intestines

- Duodenum- Major site of chemical digestion with help from liver and pancreas

Large intestines- Water absorption- Rectum and anus

III. Humans Nutrition

Milestone Questions

1. In the weightless environment of space, how does food swallowed by an astronaut reach the stomach?

2. Describe the digestion of a protein – what happens and where.

3. Where are carbohydrates digested in the body?

4. What is the function of the hepatic portal system?

5. Describe emulsification. Is the chemical, mechanical or both in terms of digestion?

Appetite Regulating Hormones

Chapter 20: Unifying Concepts of Animal Structure and Function NEW AIM: How are animals organized?...

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