Bio 122 Notes:
9-23-19 & 9-25-19
***Monday we had no notes because we took Exam 1***
o Chemical Digestion Occurs in the Small Intestine:
1.) Pancreas releases digestive enzymes that break
polysaccharides down to simple sugars, or
2.) Monosaccharides are actively transported into brush border cells, then out into interstitial fluid.
3.) Proteins are broken into polypeptides, then amino acids. 4.) Amino acids are actively transported into brush border cells, then out into interstitial fluid.
5.) Movements of the intestinal wall break up fat globules into small droplets. Bile salts coat the droplets, so that
globules cannot form again.
6.) Pancreatic enzymes digest the droplets to fatty acids and monoglycerides.
7.) Monoglycerides and fatty acids diffuse across the
plasma membrane’s lipid bilayer, into brush border cells. If you want to learn more check out What is the difference between lipids and phospholipids?
8.) In a brush border cell, the products of fat digestion for triglycerides, which associate with proteins. The resulting If you want to learn more check out What are the elements of public disclosure of private facts?
lipoproteins are then expelled by exocytosis into the
interstitial fluid inside the villus.
o Large Intestine: Our Microfloral Farm
After things pass through small intestine, a large amount of water and nutrients are already absorbed.
Whatever water, nutrients, and vitamins made by bacteria that are left are absorbed.
The bacteria is symbiotic.
Examples of problems:
o If the appendix swells up and clogs with
o Can burst if swells too much.
o Comes in the form of polyps.
How does the large intestine absorb water? Don't forget about the age old question of What do sleep deprivation studies tell us?
o Function of Large Intestine: Absorb Water If you want to learn more check out How far do you generalize a piece of knowledge?
Also houses microbes that produce vitamins.
Ex: vitamin K
Once thought that avoiding drinking cold water and being cold was a preventative of cholera.
Vibrio cholerae produces a toxin that results in pumping of Cl- into the intestinal lumen. If you want to learn more check out How to calculate a formal charge?
Na+ cannot be absorbed, and the high osmotic pressure of the intestinal lumen draws water into the intestinal lumen. Patients may produce 6 liters of watery diarrhea each day. Without prompt treatment, death by dehydration occurs in a few days.
o Herbivore Adaptations:
No animal produces cellulase.
Only protists and bacteria create this.
How to eat grass?
Microbes in compartments upstream of the acidic stomach digest cellulose.
Their stomachs contain 4 different stomach chambers. 1.) Food is ingested in esophagus and goes into
stomach chamber #1.
2.) The food then passes into stomach chamber #2. 3.) The food is then regurgitated back up the We also discuss several other topics like What is meant by the phrase “structure equals function”?
4.) The food is then re-swallowed and goes into
stomach chamber #3.
5.) The food then passes into stomach chamber #4 and then out into the small intestine.
For human molars, we have a long root and the crown is above the gumline.
For antelope molars, they have a short root and the crown is extremely long. Most of their crown is below the gumline. Saliva of cattle contains high concentrations of urea. Why? The saliva goes into 1st stomach compartment which have microbes.
In non-ruminants (ex: horses or rabbits) the microbes are housed in the large intestine.
Bunny rabbits eat their poop. Why
o So that they can digest the microbes
A horse needs to eat much more hay than a cow. Why?
o To ingest enough microbes to break down the
o Hormones & Gastric Secretion:
The taste, smell, touch sensation, or thought of food sends nervous impulses to the brain.
The nervous impulses cause neurons to stimulate secretion of hydrochloric acid and pepsin into the stomach.
o Carnivores & Herbivores: Gut Anatomy
o Looks similar in both carnivores and
o MUCH larger than the herbivore’s small
o Very small on carnivores.
Colon (large intestine)
o Straight on carnivores.
o Looks similar in both herbivores and
o Much shorter and less condense than the
o Very long and curled, unlike the carnivores.
Colon (large intestine)
o Much longer and condensed than the
- Giant Pandas are in the Order Carnivora, or meat eaters, but they eat only bamboo plants. Compared to other bears, the panda intestinal tract is what? About the same length as other bears.
- Compared to other bears, the metabolic rate of pandas is what? Low.
- What would you predict about the levels of thyroid hormone in the blood of giant pandas compared to other bears? That it is lower in giant pandas.
- Animals: Respiration
o Respiration Has Different Levels in Different Animals: Homo sapiens cannot handle high altitude.
Because of low oxygen.
Bar headed goose, Anser indicus, can handle high altitude.
o Not All Animals Have Lungs or Gills:
Not all animals have special respiratory surface.
If an animal is thin, they can just take oxygen up with their skin.
Examples: sponges, flat worms, & jellyfish.
o Gas Exchange During Respiration:
Gas exchange is the process of taking up oxygen and releasing carbon dioxide from metabolic processes in
Not enough oxygen = you won’t live long.
Respiration serves as a means for the body to exchange gases with the atmosphere via the blood.
Some animals use the skin as a gas exchange organ. Ex: Lungless salamander.
Skin has to be wet to dissolve gas.
OK for low oxygen demand.
Aquatic animals must be thin.
Some animals get O2 from the atmosphere or from the water column.
Air = 20% O2
Water = 0.7% O2
- In terrestrial animals, ventilation rate is most sensitive to changes in what? Blood pH
- A list of proteins that reversibly bind to O2 are what? Hemoglobin, Hemocyanin, & Myoglobin.
o Aquatic Respiration:
The amount of gas that dissolves in water depends on the solubility coefficient and partial pressure of the gas in
contact with the water.
Increasing temperature reduces solubility of gases.
Increasing salinity reduces solubility of gases.
FW at 15 degrees C contains 7.2 ml O2/L.
SW at 15 degrees C contains 5.8 ml O2/L.
o Aquatic Gas Exchange Organs: Gills
Getting oxygen underwater can be somewhat difficult.
Examples of creatures that adapted:
Larval salamander with external gills.
o Bluefin Tuna (Thunnus thynnus):
This animal has a high oxygen demand.
What adaptations are present in its gas exchange organs? - Fish Gills
o All Fish Gills Have This:
Large surface area
A.) Bony fish with its gill cover removed. Water flows in through the mouth, over the gills, then out through
the gill slits. Each gill has bony gill arches with many
thin gill filaments attached.
B.) Two gill arches with filaments.
C.) Countercurrent exchange: flow of water and blood. D.) Oxygen flow from water into a capillary. All along the capillary, oxygen flows down its concentration
gradient from water into blood.
o Mechanisms of Ventilation in Fish:
1.) Mouth opens and the jaw is lowered to draw water into the buccal cavity. The operculum then pulls away from the body, expanding the opercular cavity.
2.) Mouth closes and the lower jaw raises, which squeezes water toward the opercular cavity. Water is forced across the gills and out through the open operculum.
3.) Operculum closes and the cycle begins again.
A.) Buccal pumping.
B.) Ram ventilation.
o Saving energy by swimming with mouths open
to ventilate their gills.
o Efficiency of O2 extraction in ram ventilators
o Oxygen Availability on Land:
As the meters above sea level increase, the atmospheric pressure decreases.
At sea level there is more oxygen than at the top of Mt. Everest.
Less than half of what is at sea level.
Terrestrial animals: desiccation is a problem
- Insect Tracheal System
o Insect Tracheal System Contains:
Trachea (tube inside body).
Spiracle (opening to body surface).
The tracheal system is part of the exoskeleton and is shed during molts.
o Respiratory Organs of Terrestrial Animals Vary:
Land snail: vascularized skin inside mantle cavity.
They have blood supply inside mantle to take up
- Does a frog or a snake use their skin for gas exchange? A frog. - Lungs
o Human Lungs Execute This for Success:
Mucus cilia for cleaning.
Surfactants prevent alveolar collapse.
o Human Lungs Contain:
Oral Cavity (mouth)
Supplemental airway when breathing is labored.
Double-layer membrane that separates lungs from
other organs; the narrow, fluid-filled space between
its 2 layers has roles in breathing.
At rib cage, skeletal muscles with roles in breathing.
There are 2 sets of intercoastal muscles (external and
Muscle sheet between the chest cavity and abdominal cavity with roles in breathing.
Chamber in which air is moistened, warmed, and
filtered, and in which sounds resonate.
Always connecting nasal cavity and mouth with
larynx; enhances sounds; also connects with
Closes off larynx during swallowing.
Larynx (voice box)
Airway where sound is produced; closed off during
Airway connecting larynx with 2 bronchi that lead into the lungs.
Lung (one of a pair)
Lobed, elastic organ of breathing; site of gas
exchange between internal environment and outside
Increasingly branched airways starting with 2 bronchi and ending at air sacs (alveoli) of lung tissue.
o Mechanism of Ventilation in the Human Lung:
2 sets of muscles involved:
Diaphragm contracts, moves down.
External intercostal muscles contract, life rib cage
upward and outward.
Lung volume expands.
Diaphragm, external intercostal muscles return to
Rib cage moves down.
Lungs recoil passively.
- Gas Exchange in Birds
o Birds Contain:
Posterior air sacs.
Scanning electron micrograph of a bird lung tissue
shows tubes through which air flows to and from air
Anterior air sacs.
o Schmidt-Nielsen Figures Out What Air Sacs Do:
Avian air sacs direct the flow of air through the lungs. Key Materials
Ostriches, gas analyzer, & oxygen tank.
Analyze gas contents in anterior and posterior air
sacs, using an air-sampling syringe.
The Data Results from Experiment 1
The researchers proposed that air moves directly to posterior sacs, then through the lungs, and then to
the anterior sacs.
Anterior air sacs= low O2 & high CO2.
o Air sac has been passed through the lungs.
Posterior air sacs= 21% O2 & low CO2.
o Air sac hasn’t been passed through the lungs.
Give ostriches a single breath of pure O2, which can be tracked as it moves through the respiratory
Then remove the mask and allow the bird to breathe normal air.
- Terrestrial Animals
o Control of Ventilation: Terrestrial Animals
Blood pH controls the rate of ventilation.
Ex: Hyperventilating makes the pH higher (more
CO2 + H2O = H2CO3 (carbonic acid) = H+ + HCO3-. Makes blood acidic.
CO2 concentration and acidity rise in the blood and
Tidal volume and rate of breathing change.
CO2 concentration and acidity decline in the blood
and cerebrospinal fluid.
o Respiratory Proteins:
We need proteins that carry oxygen from lungs to tissues. 2 main proteins.
o Uses iron to bind oxygen
o Found in arthropods (but not in insects).
These proteins increase O2 carrying capacity of
hemolymph in the blood.
- Anatomy of an Alveolus
o Surface View of Capillaries Associated with Alveoli Contain: Cutaway view of one alveolus and adjacent pulmonary capillaries.
Has pore for air flow between adjoining alveoli.
Has red blood cells inside pulmonary capillary.
Has air space inside alveolus (very thin).
Three components of the respiratory membrane.
Alveolar (thin) epithelium.
Fused basement membranes of both epithelial