cnidaria

platyhelminthes

nematoda

mollusca

annelida

arthropoda

echinodermata

chordata

coelenterates

stinging cells 

anemones 

jellyfish

coral

hydras

platyhelminthes

flatworms

plenarians

slugs, snails

mollusks

squids

octupus

arthropods

crabs

lobsters

shrimp

insects

sea stars

sea urchins

sea cucumbers

two openings- mouth and anus

higher on evolutionary tree than incomplete digestive tract

more specific adaptations of body parts

regional specialization

increased SA of absorption area

less waste

part of gut for mechanical degradation, protein digestion, lipid digestion, carb digestion, absorption

some animals specialized compartment for food storage

one opening only

food and waste move through the same opening

nutrient procurement by cnidarians/ coelenterates

Hydra

characterized by stinging cells (nematocysts)

Incomplete digestive tract

stings prey with tentacles

grings to mouth and enters gastrovascular cavity

enzymes ecreted by gastrodermis

mostly intracellular digestion

extracellular digestion in GV cavity to get particles small enough for intracellular

folds in GA cavity to maximize SA

2-cell layer walls for more exchange with the environment

Nutrient Procurement by Flatworms

(Platyhelminthes)

incomplete digestive tract

same principles of hydras (no stinging cells)

 body cell wall only 2 cells thick

pharynx- sucks up food

extracellular digestion to break down some

intracellular as well

flatness and branching of GV cavity maximizes SA

Nutrient procurement by earthworms

annelida

complete digestive tract

mouth- takes in soil/decaying material

pharynx- sucks food in, has mucous, enzymes

esophagus- connects to crop

crop-storage chamber

gizzard- grinds up with stones

intestine- enzymes, digestion, reabsorption of water, 

EXTRACELLULAR digestion only!

great regional specialization

highly adapted

mechanical breakdown

lubrication

begin enzymatic digestion

microbicide

taste and smell

2 incisors (biting, chisel shaped)

1 canine (for tearing meat, sharp, pointed)

2 premolars 

3 molars (flattened, for grinding and crushing)

heterodont- not all the same

homodont- teeth all the same

carnivore- all large canines

herbivores- broad flat teeth for grinding cell walls

rodents- extremely large incisors for gnawing

tongue- manipulates food into a bolus (food mass prepared for swallowing)

salivary glands- release saliva with digestive enzymes

connects with stomach

uses paristalsis

muscular contraction that pushes bolues and food ahead of it

sphincter muscle: between stomach and esophagus normally closed opens when peristalsis reaches it

within are gastric glands

overproduction of gastric acid

eats a hole in the stomach wall

mucosa makes that a rare occurence

most ulcers are duodenal

stores and releases bile

bile facilitates fat digestion

breaks down fat droplets into smaller ones

absorbs water and electrolytes from chyme

 forms and stores feces

in herbivores

helps digest cellulose

not very efficient

contains lots of microorganisms

ruminants

fermentation chamber for digestion of cellulose

bacteria symbionts live in rumen and reticulum, break down cellulose and produce glucose

chyme from the rumen is regurgitated and chewed more as cud

then returned to abomassum and omasum (more like typical stomach)

carnivores- short, straight intestine

herbivores- long and coiled

omnivores- intermediate

rabbits form two types of feces

ones is materials from the cecum- reingest it

other type is waste

all cells must have access to necessary gases

Organisms that have cells not in contact with the medium must have an internal transport or circulatory system: blood

Thick defensive covering makes it difficult for O2 to diffuse through to the cells

most terrestrial organisms have a water impermeable covering (cuticle, feathers, hair, hide) preventing water loss

also inhibits gas exchange

need a non-scaly, non-waxy, non-hairy gas exchange organ

also need special gas exhange organ with high SA

rate of metabolism determines how fast oxygen is used up and how fast it must be supplied to tissues

plants have very low MR

ectotherms have low MR

endotherms have high MR: need 10-20x more oxygen

1. none

2. cutaneous

3. papulae (respiratory tree)

4. Tracheal systems

5. Gills

6. Lungs

used by some small multicellular animals

use their body surface as an exchange surface

blood transports gases to and from the surface

usually in multicellular aquatic organisms

evaginated exchange surfaces

vary in structure

usually highly vascularized

gills ( aquatic insects)

have many different types of evaginations (gills)

evaginated structures bad in terrestrial environment cuz of water loss

diff insect species have diff parts of body evaginated

clams, oysters, scallops,

highly folded gills

use cilia to draw water in and they also pick up food particles as well as O2

have very thin cuticle covering

housed in gill chamber on outside of body, but covered by fold of body

highly folded, subdivided to compose huge SA for exchange surface

no scales cover gills

very thin and highly vascularized

water enters through mouth, buccal pump to move it across gills and out

gills covered by flap (operculum)

O2 poor blood enters each filament and crosses the lamellae where it picks up O2 and leaves CO2

uses a countercurrent flow to effectively pick up O2 and CO2

enhances O2 tranfer

water flowing in one direction transfers O2 to blood moving in the opposite direction

 opposite flows maintain diffusion gradient that enhances the transfer of O2

Gills can remove up to 90% of the O2 dissolved in water

Salamanders: exposed, not covered, O2 rich stream water flows past so no need to pump water

Some fish and sharks must constantly be in motion to force water through gills

Found in horseshoe crabs, some arachnids

evaginated into open body cavity

puts terrestrial animals at high risk of dessication

found in echinoderms (starfish)

simples gills that increase surface area for purpose of gas exchange

kind of like cutaneous but has projections on surface

Found in Echinoderms (sea cucumbers)

invaginated gas exchange system

pulls water in through anus which circulates through the respiratory tree

found in terrestrial arthropods: insects, some arachnids

terrestrial arthropods have thick cuticle to prevent dessication and protection, high metabolic rate (especially those that fly)

is a diffuse invaginated system with many parts

part of tracheal system found in arthropods

openings to the outside

closed by valves or flaps when not breathing to prevent dessication

part of tracheal system in arthropods

narrow tubes that branch out from spiracles into the rest of the body

part of tracheal system in arthropods

many smaller branches that carry air to the individual cells

no active cells are more then 1mm from tracheole

invaginated

localized (limited to a particular region of the organism)

highly vascularized

found in snails and higher vertebrates

endoderms have very efficient lungs because greatest demand for oxygen

nostrils

nasal cavity

pharynx

glottis

larynx

trachea

bronchi

bronchioles

alveoli

pharynx

from larynx to thoracic cavity

epithelial cavity ciliate: carries foreign particles and mucus away from the lungs

grape-like clusters of air-sacs

main site of gas exchange (occurs across aolveolar membrane)

alveoli lining only 1 cell thick

surrounded by capillaries

mammalian repiratory system

gas exchange

connected to the circulatory system

alveolus surrounded by capillary bed

gas exchange occurs across alveolar epithelial cell and capillary endothelial cell

gas exchange works by diffusion

not a counter current, so not very efficient

oxygen and CO2 must be dissolved in water so repiratory tract must be moist

 conserve water by counter-current exchange of moisture

cool dry air in through nose, warms and gains moisture in passages, warm, moist air comes up from lungs, passageways absorb the warmth and moisture and mostly cool dry air is exhaled

especially important for animals in arid environments

tidal vent of terrestrial animals makes this conservation possible: air moving and and out same passageway

inhale by contracting the diaphragm

lungs- stretchy sacs that can't move air by themselves

can also stretch intercostals(muscles btw ribs) to do chest breathing

contraction of the diaphragm increases the volume of the thoracic cavity and decreases air pressure, which draws in air from outside

Mucous covers the epithelium of the respiratory system which traps particles, which are then swept out of the system by cilia

tobacco smoke- destroys cilia and epithelial cells

allows more toxins to reach the lungs, frequent coughing is the bodys attempt of cleaning itself

Emphysema- from cigarettes, alveoli become brittle and break

Lung cancer- nearly always fatal

passive

diaphragm relaxes- causes a decrease in lung size

air is forced out until inside of lung reaches atm pressure

lungs have a lot of elastic tissue and would recoil more if they could but pressure keeps them inflated

(prevents collapsed lung)

Can be conciously controlled

Mostly automatically controlled by control centers in the brain that regulate breathing

Located in the pons and the medulla oblongata

Neurons in the medulla oblongata moniter the pH of the blood and the cerebro spinal fluid(influenced by the pH of the blood)

The pH starts to drop when the amount of CO2 starts to increase in the blood, 

CO2 undergoes a chemical reaction and forms carbonic acid, which lowers the pH of the blood

Medulla senses the drop and then increases the breathing rate and depth

More CO2 is eliminated and the pH returns to normal

More efficient than in mammals

One-way flow of air through the lungs

Have paired lungs, but 8-9 air sacs connected to teh lungs

Air sacs push air through the lungs in one direction (not like tidal breathing)

Allows for countercurrent exchange in lungs

hydra, flatworm

essentially internal transport system with no circulatory system

circulate gases and nutrients, wastes and hormones, antibodies and heat to teh areas of the body that need them

2 circuits in humans, pulmonary and systemic

Blood (Hemolymph) flows into large open areas (sinuses)

Not always enclosed in vessels

Flows through tissue in extracellular (interstitial) spaces

Mollusks, arthropods, and crustaceans,

Typically dorsal heart with holes, (ostia)

Hemolymph in space around heart, enters the heart through the ostia and leaves through vessels when the heart contracts 

Hemolymph responsible for everything except gas exchange 

Blood travels through the body in well defined vessels (arteries away from the heart and veins to the heart, capillaries exhanges vessels)

Blood cells and proteins stay in the vessels

Small molecules and water move in and out of capillaries

Blood and extracellular fluid(interstitial fluid) are of different composition

Vertebrate Circulatory Systems

(Fish)

Single current of blood flow

Heart, gills, tissue, heart

Chamber of heart in line, no mixing of blood

Blood pressure after gills is low, limits rate of O2 to rest of the body

Have a much bigger heart to try to create higher pressure

Completely separate pulmonary and systemic circuits

4-chambered heart

Can use higher pressure to get to systemic ciruit w/out blowing the lungs out

no dilution of oxygenated blood

Systemic blood-

superior/inferior vena cavae

right atrium

tricuspid valve

right venticle

semilunar valve

pulmonary trunk

pulmonary arteries

pulmonary arterioles

capillaries 

pulmonary venules

pulmonary veins

left atrium

bicuspid valve

left ventricle

aortic semilunar valve

aorta

Cardiac Cycle

The rythmic control of the atria and ventricles

relaxation of the heart

when heart fills with blood

Both atria and ventricles relax

blood enters heart from venae cavae and the pulmonary veins

Bi and tricuspid valves open blood flows into the ventricles

both atria contract and push the blood into the ventricles

the bicupsid and tricuspid valves close

semilunar valves open

ventricles contract and push blood into the aorta and pulmonary arteries

the semilunar valves close to prevent backflow and ventricles relax

blood pressure forces the semilunar valves open during systole, very high

very low blood pressure during diastole as a result of the elasticity of the artery walls

Heart is self-stimulating

Sino-atrial node (right above right atrium) sends nervous impulse across atria causing contraction 

Atrio-ventricular node- impulse from S-A node hits A-V node in wall btw right A and V slows down nervous impulse then pass on to the rest of the ventricle throught the bundle of His which generates contraction of ventricles

Cardiac muscle is both excitable (can conduct impulses like nerves) and contractile (can contract like other muscles)