COMPANA LAB (LE4)

Digestive system 

• turns the food you eat into nutrients

• mechanical processing + secretion of water, acids, enzymes, buffer, and salt

• excretion of waste products

• Gastrointestinal tract

• Accessory organs

Divisions of the digestive system

Gastrointestinal (GI) tract

• also called digestive tract or alimentary canal 

• pathway by which food enters the body and solid wastes are expelled 

• Mouth

• Esophagus

• stomach

• small intestine

• large intestine

Gastrointestinal (GI) Tract composed of: 

Mastication (chewing)

initiates the digestive process

• Incisors

• Canines

• Premolars

• Molars 

Types of tooth

Shape: Sharp, Flat, Chisel-shaped

Function: Cutting and slicing food

Shape and function of Incisors 

Shape: Pointed, cone-shaped

Function: Tearing and gripping food

Shape and function of Canines 

Shape: Broad, flat, ridged

Function: Crushing and grinding food 

Shape and function of Premolars

Shape: Large, flat, ridged 

Function: Chewing and grinding food 

Shape and function of Molars

Heterodont

(“many” + “teeth”) = mammals

Homodont

(“one” + “teeth”) = vertebrates other than mammals

Peristalsis (Esophagus)

is a series of wave-like muscle contractions that move food through the digestive tract 

Stomach acid 

Is strong enough to dissolve stainless steel. 

sticky, neutralizing mucus 

The stomach protects itself by secreting __________ that clings to the stomach walls 

to allow it to expands and efficiently aid in digestion

why is the stomach wall make of many folds (rugae)

chyme

Food + digestive acids and enzymes

• Bringing up partially digested food from its crop

• Baby birds are completely dependent on their bird parents

• regurgitate small amounts of food that they then feed to the babies

• used as an act during courting, as it the bird were saying, “Look how well I can provide for you and our future family” 

regurgitation in birds 

Borborygmi 

• Growling or rumbling sounds that the stomach and intestines make as food, fluids, and gas pass through them 

• Sounds are usually most noticeable when you’re hungry

Eructation/belching

• Burping

• release of gas from the upper digestive tract

• One Common cause is eating too fast

• faster you eat, more likely to swallow extra air 

“Butterflies” in the stomach 

• Body reacts to stress or excitement through the fight-or-flight response 

• Adrenaline is released, increasing heart rate and alertness

• Blood flow shifts away from the stomach to the muscles and brain

• Digestion slows down, making the stomach more sensitive 

• Vagus nerve connects the brain and stomach, making the gut more sensitive to stress

• Reduced digestive activity causes mild stomach contractions, creating the fluttering “butterflies” sensation. 

Small intestine 

Carries the major digestion and absorption of digested food (90%) 

Mesentary

Is a continuous set if tissues that attaches your intestines to the wall of your abdomen and holds them is place

villi

Lined with _____i, finger-like projections made up of cells that increase surface area for nutrient absorption

Gi Tract: Large Intestine

is responsible for the absorption of water from the indigestible residue of food and getting rid of any waste products left over

Feces (Poop or solid waste)

in the large intestine, food is turned into

Flatulence (fart)

is primarily a result of bacteria in the large intestine fermenting undigested carbohydrates, like sugars and fibers. This fermentation produces gases as byproducts.

primarily related to the gases produced in the digestive process and the individuals diet and gut microbiota. Foods high in sulfur cause smellier farts

whether fart is silent or not doesnt determine its odor. Smell is

Accesory organs

• not part of the digestive tract or alimentary canal

• salivary glands, liver, gallbladder, and pancreas

• secrete or store substances that pass through ducts into the gastrointestinal tract

salivary glands

saliva Secretes a-amylase (ptyalin) which begins starch digestion in the mouth. the more you chew the food, the easier it is for the stomach to digest it

liver

secretes bile which digest and absorbs fat

bile

green substance that cuts fats into smaller pieces

regenerative capacity of any organ in the body

the liver has the greatest

gall bladder

stores and concentrates excess bile secreted liver, if not immediately needed

Pancreas

neutralizes acidic chyme by releasing bicarbonate ions breaks down protein, fats and carbohydrates

• ingestion

• propulsion

• mechanical digestion

• chemical digestion

• absorption

• defecation

digestive processes are:

• Single-chambered stomach

Human and rabbit digestive system

• Proventriculus

• Gizzard

two-chambered heart (birds)

Proventriculus

where gastric juices are produced

gizzard

• food is stored, soaked and mechanically ground

• birds swallow small stone or grit, which stay in the gizzard to help crush and grind food further

• Second stomach for birds

Crop

for temporary food storage

Multi chambered heart

Cows

Rumen

• largest chamber

• fermentation chamber for the initial breakdown of ingested food

Reticulum

Aids in particle breakdown and regurgitation

Omasum

absorbs water and nutrients

Abomasum

functions as the true stomach, secreting digestive enzymes to break down food before absorption 

churning

stomach contraction

rugae

stomach folds

Simple system with variations in tract length; acidic stomach in carnivores

Digestive system overview for fish

Standard organs, including muscular stomach for whole prey digestion 

Digestive system overview for amphibians 

includes standard organs; slower digestion due to low metabolism

Digestive system overview for reptiles

Specialized with crop for storage and gizzard for grinding

Digestive system overview for birds

Complex, with diet-specific adaptations; herbivorous may have multi-chambered stomachs 

Digestive system overview for mammals

shorter tracts in carnivores, longer in herbivores; adaptations for filter feeding in some species 

Prominent differences for fish

adapted for both aquatic and terrestrial diets; swallow prey whole, requiring stronger stomach muscles 

Prominent differences for amphibians

low metabolic rate results in slower digestion; some herbivores have a larger cecum for plants

Prominent differences for reptiles

Crop and gizzard compensate for lack of teeth; efficient system for high metabolism

Prominent differences for birds

multi-chambered stomachs in herbivores, shorter simpler tracts in carnivores; varied digestive length based on diet

Prominent differences for mammals

Respiratory system 

• supplies body with oxygen

• elimination of carbon dioxide

• humidifier

• filters and warms the air

• speech

respiratory system functions

• upper respiratory tract

• lower respiratory tract

divisions if the respiratory system

• nasal cavity

• paranasal sinuses

• Pharynx (throat)

upper respiratory tract

nasal cavity

with hairs and mucus membranes, filters air

paranasal sinuses

air-filled, contribute to air humidifying and and warming

Pharynx throat

passageway

• trachea

• larynx

• bronchi

• bronchioles

• lungs

• alveoli

Lower respiratory tract

larynx

aka voicebox, routes air and food into proper channels

trachea

aka windpipe, main airway to the lungs

adam’s apple

thyroid cartilage

Choking

also known as foreign body airway obstruction (FBAO)

Heimlich maneuver 

Heimlich maneuver 

trachea 

windpipe-like tube that carries air from the throat to the lungs 

bronchus

branch from the trachea into each lung

branchioles

smallest of the conducting branches

alveoli

end, site for gas exchange

right lung

• three lobes

• shorter due to the liver below

left lung

• two lobes

• longer and narrower

• has an cardiac notch

inspiration (breathing in)

breathing in

Ribs = Move upwards and outwards

Diaphragm = contracts and flattens

Lungs = expand

Lung volume = increases

Lung pressure = Decreases 

Movements of ribs, diaphragm, lungs, lung volume, lung pressure when breathing in (inspiration)

expiration

breathing out

Ribs = Move back down and in 

Diaphragm =relaxes - returns to staring position (dome-shaped)

Lungs = Reduced in size 

Lung volume = decreases

Lung pressure = increases

Movements of ribs, diaphragm, lungs, lung volume, lung pressure when breathing out (expiration) 

Buccal pumping

• animal opens its mouth, allowing water or air to enter the buccal cavity

• Eyes lowers to push air down

• It then closes its mouth and expands the throat (buccal cavity), creating pressure that pushes the water or air into the gills or lungs

• Air or water is then expelled by the contraction of the throat, and the process repeats 

Ram ventilation

• swimming with mouth opens

• constant forward swimming motion. Water enters the mouth as the fish moves forward. water flows over the gills, extracting oxygen, and then exits through gill openings

• allows for efficient oxygen extraction without the need for active pumping mechanisms.

-Sharks that use both buccal pumping and ram ventilation, they can breathe

• Other sharks such as great whites, hammerhead, and mako will die

will a shark drown if it stops moving

• no

• but fish can suffocate when fresh water does not gave enough oxygen

can a fish drown

• First inhale - fresh air goes into air sacs in the back, not the lungs

• first exhale - fresh air moves into the lungs to give oxygen to the bird

• Second inhale - the now “used “ air moves into front air sacs

• second exhale - used air leaves the body

How birds breathe

• Cloacal respiration

Turtle breathing

Cloacal respiration

• butt breathers

• when turtles hibernate, main source of oxygen is through their butt

• turtles get oxygen from the water by moving it over their body surfaces covered in blood vessels

• turtles have a cloaca, which is essentially their butt, that has many blood vessels, so the most efficient way to get oxygen is through the cloaca, hence the term cloacal respiration

Use gills for extracting oxygen from water; water flows over gills where oxygen is absorbed into the bloodstream 

Respiratory system overview for fish 

Use lungs, skin, and sometimes gills (especially in larvae) for respiration

Respiratory system overview for amphibians

Primarily use lungs with a more complex structure than amphibians; no cutaneous respiration

Respiratory system overview for reptiles

have lungs and air sacs that create a one-way airflow, ensuring continuous oxygen supply 

Respiratory system overview for birds 

use lungs with a diaphragm that assists in breathing; alveoli increase surface area for gas exchange

Respiratory system overview for mammals

Only vertebrates with gills as primary respiratory organs; rely on buccal pumping or ram ventilation for water flow

Prominent differences for fishes

Unique cutaneous respiration (breathing through skin); lung structure is simple and sac-like

Prominent differences for amphibians

Lungs have greater surface area than amphibians, adapted for land; rely solely on lungs without skin breathing 

Prominent differences for reptiles

most efficient respiratory system among vertebrates; unique air sac system supports high metabolism and flight

Prominent differences for birds

Use a muscular diaphragm for efficient ventilation; alveolar structure provides large surface area for gas exchange 

Prominent differences for mammals