Digestion and Waste Flashcards
Why do we eat?
To obtain Nutrients (Essential nutrients )
To obtain Energy- ATP
To obtain carbon (to build macromolecules)
To obtain lots of nutrients especially ‘essential nutrients”
(essential fatty acids mineral amino acids minerals) (things we cant make ourselves
What are 4 types of macromolecules?
nucleic acids(Rna DNA), proteins polysaccharides, fat
What are organic compounds ?
Complex carbon-based molecules that are arranged in chains or rings
What are polymers ?
Longs chains of individual organic molecules (monomer)
What are the monomers that make up nucleic acid’s proteins and polysaccharides?
Nucleotides
Amino acids
Monosaccharides
What are enzymes?
are proteins that break down other molecules
Named after the thing they break plus ‘ase’
Essential Nutrient
We make most fatty acids and amino acids (out of individual elements starting with carbon)
The ones we can’t make are essential and must be obtained from the diet
Why is a plant diet important?
Plants make many essential nutrients
That’s why a plant diet is important
Cultures around the world developed complete diets
Beans and rice to obtain all essential amino acids
Vitamins
Organic molecules needed for metabolism
Act as coenzyme
Pro vitamin
molecule we need to eat this is almost a vitamin and our body will convert it to what we need
What are
2 types of vitamins ?
Water soluble
fat soluble
Minerals
Inorganic molecule Ex; sodium potassium (many elements) We need many in trace amounts Found in many foods Can be toxic in excess amounts
Bulk feeding
most animals including humans
eating large pieces of food
Substrate feeding
are animals that live in or on their food source
ex- maggots moth caterpillar
Fluid feeding
suck nutrient rich fluid from a living host
ex- humming birds bees(beneficial) parasites aphids mosquitoes
Ingestion
taking food into the body
Digestion
Breaking down food into smaller pieces
Doesn’t matter if its inside out outside the body
Absorption
the animals cells take up (absorb) small molecules such as amino acids and simple sugars
Elimination
the passing of undigested material out of the body
Gastrovascular cavity
A central cavity with a single opening in the body of certain animals, including cnidarians and flatworms, that functions in both the digestion and distribution of nutrients
Alimentary canal
a complete digestive tract consisting of a tube running between a mouth and an anus
Incisor
the front teeth present in most mammals
Canine
a pointed tooth between the incisors and premolars of a mammal, often greatly enlarged in carnivores
Premolar
are transitional teeth located between the canine and molar teeth.
have a flat biting surface
Molar
are large, flat teeth at the back of the mouth
Cellulose
humans cant digest this it passes through like a fiber
Cellulase
an enzyme that convert cellulose into glucose or a disaccharide
Ammonia
a small toxic molecule produced as a metabolic waste product of protein and nucleic acid metabolism
Breaking peptide bonds results in this
Easily diffuse into water
No additional cost in its removal
Urea
A soluble nitrogenous waste produced in the liver by a metabolic cycle that combines ammonia with carbon dioxide
uric acid
A product of protein and purine metabolism and the major nitrogenous waste product of insects, land snails, and many reptiles. Uric acid is relatively nontoxic and largely insoluble
filtration
In excretory systems, the extraction of water and small solutes, including metabolic wastes, from the body fluid.
Reabsorption
In excretory systems, the recovery of solutes and water from filtrate.
Excretion
The disposal of nitrogen-containing metabolites and other waste products.
Protonephridium
An excretory system, such as the flame bulb system of flatworms, consisting of a network of tubules lacking internal openings.
Metanephridium
An excretory organ found in many invertebrates that typically consists of tubules connecting ciliated internal openings to external openings
Malpighian tubule
A unique excretory organ of insects that empties into the digestive tract, removes nitrogenous wastes from the hemolymph, and functions in osmoregulation
Nephron
a nephron with a loop of Henle located almost entirely in the renal cortex
Explain the four stages of urine production.
- Filtration
Blood pressure pushes water and solutes across filter membrane (glomerulus (ball of cells or capillaries))
Outer opening is small than inner opening so pressure pushes stuff out into membrane into excretory tubule that’s called filtrate
body fluid (blood, coelomic fluid, or hemolymph) is brought in contact with the selectively permeable barrier that acts as a biological filter. (blood pressure in many animals) drives a process of filtration. Cells, as well as proteins and other large molecules, encounter the filter but cannot penetrate it and remain in the body fluid. In contrast, water and small solutes such as salts, sugars, amino acids, and nitrogenous wastes cross the filter, forming a solution called the filtrate. - Reabsorption
Water and important solutes that the animal wants are absorbed back from the excretory tubule into the capillary (salts sugars amino acids bicarbonate water) are returned to the blood either actively or passively
Whats left over after you reclaim water and solutes, things you didn’t want ammonia and toxins in the excretory tubule which eventually becomes urine - Secretion
Toxins (drugs) are actively secreted out of blood into the excretory tube;(active transport ATP pumps ) - Excretion
filtrate(containing nitrogenous waste) is excreted as urine (hopefully very concentrated if you have reclaimed most water)
Describe the linkages between the digestive, respiratory, renal, and circulatory systems.
“The respiratory system brings oxygen into the lungs when you breathe. The digestive system breaks food down into nutrients such as glucose. Now the circulatory system enters the picture. It transports glucose and other nutrients from the digestive system to the cells.”
Water soluble
The B vitamins (B1 B2 B3 B5 B6 B7 B9 B12)
Vitamin c
Get these from plants mostly or milk
Fat soluble
A D E K
Get these from plants mostly
excesses of fat-soluble vitamins accumulate in the fat stores and can be released to the blood when the fat is metabolized, causing toxicity
Who was Linus Pauling and what did he believe?
Chemist
Known for his push for vitamin c consumption (came to know that the more you consume the better but there is no evidence supporting this )
Any excess vitamin C gets peed out of body because they are water soluble
Are minerals essential?
We cannot make these, so these are essential
What is an easy way of ensuring a balanced diet?
Colorful diet
Explain the four stages of food processing by animals
1. Ingestion Taking food into body 2. Digestion Mechanical digestion (Breaking down of food / chewing) Chemical digestion 3. Absorption Absorbed by tissues and cells and used 4. Elimination
These don’t have in this exact order (do digestion outside of body such as starfish)
Identify examples of the four animal feeding mechanisms.
filter feeding- humpback whales
substrate feeding- caterpillar larvae of moth
fluid feeding- aphids parasites hummingbirds bees
bulk feeding- most animals humans (snakes)
Describe the benefits of eating a prey item in pieces rather than whole.
When you eat it in a whole piece it takes a very long time to digest need to get it across the membranes, if you swallow a piece of pie you won’t be able to shove pie through intestinal lining into the blood stream and you’re body cells won’t be able to do anything with a piece of pie, so you need to break it down to be able to do anything with it *
Predict a mammal’s diet based on its dental formula.
- Carnivore (dog and cats)
- have large pointed incisors and canines that are used to kill prey and rip/cut pieces of flesh
- jagged premolars and molars crush and shred food - Herbivore (horses deer)
- have premolars and molars with broad ridged surfaces and grind tough plant material
- incisors and canines are modified for biting off pieces of vegetation
- in some canines are absent - Omnivore (humans)
- adapted to eating both plants and meat
- adults have 32 teeth
- 4 bladelike incisors for biting
- pair of canines for tearing
- 4 pre molars for grinding
- 6 molars for crushing
Compare internal and external digestion.
a. Identify which animals employ intracellular digestion, extracellular digestion, or both.
INTRACELLULAR
Food vacuoles—cellular organelles in which hydrolytic enzymes break down food—are the simplest digestive compartments
The hydrolysis of food inside vacuoles, called intracellular digestion, begins after a cell engulfs solid food by phagocytosis or liquid food by pinocytosis
Newly formed food vacuoles fuse with lysosomes, organelles containing hydrolytic enzymes. This fusion of organelles brings food in contact with the enzymes, allowing digestion to occur safely within a compartment enclosed by a protective membrane
EX- SPONGES
EXTRACELLULAR
hydrolysis of food begins with extracellular digestion, the breakdown of food in compartments that are continuous with the outside of the animal’s body. Having one or more extracellular compartments for digestion enables an animal to devour much larger pieces of food than can be ingested by phagocytosis
EX- CNIDARINS FLATWORMS MOST ANIMALS
Discuss, with examples, the effects of increasing intestinal surface area on efficiency.
Intestine consists of many Circular folds
The folds contain Villi
Each villi contain Microvilli
Why?
Massively Increase SA which greatly increases the rate of nutrient absorption (this happens in mitochondria and brain)
Simple tube would mean little surface area and not much would be absorbed it would just pass through & get out the body
tons of lining where nutrients can pass in & out
Summarise mechanisms that herbivores use to breakdown cellulose
mutualistic symbiosis is particularly important in herbivores
much of the chemical energy in herbivore diets comes from the cellulose of plant cell walls, but animals don’t produce enzymes that hydrolyze cellulose
instead many vertebrates (& termites) host large populations of mutualistic bacteria & protists in fermentation chambers in their alimentary canals
these microorganisms have enzymes that can digest cellulose to simple sugars & other compounds that the animal can absorb
What type of digestive compartment do all other animals have?
most animals have a digestive tube extending between two openings, a mouth and an anus called a complete digestive tract or, an alimentary canal
Discuss the advantages of an alimentary canal over a gastrovascular cavity
food moves along the alimentary canal in a single direction, the tube can be organized into specialized compartments that carry out digestion and nutrient absorption in a stepwise fashion(different things can happen simultaneously)
An animal with an alimentary canal can ingest food while earlier meals are still being digested,something that is likely to be difficult or inefficient for animals with gastrovascular cavities
Crop
before the stomach Mostly food storage chamber Honeybees have this but no digestion happens here its just a food chamber with hard endoskeleton Little if any digestion Worms' insects birds
Stomach
Some digestion some food storage very little absorption
Alcohol goes through stomach very quickly
Insects (midgut, birds’ mammals)
Gizzard
Some food storage Some digestion (often with rocks) Birds and worms have this rocks help break up food
Small intestines
Some digestion, most absorption
Large intestine
(hindgut in insects)
Waste compaction and water recovery
What are 2 main types of organs in our digestive system
accessory organs(ex; salivary glands gallbladder) (not part of digestive system(alimentary canal) but play a big role in digestion) and those that make up alimentary canal
Where does digestion begin?
begins in mouth (also ingestion in our species)
Mechanical digestion: teeth (and to some extent the tongue) begin breaking up food.
Chemical digestion: salivary amylase begins hydrolyzing starch (plant glucose polymers) and glycogen (animal balls of glucose) into disaccharides or monosaccharides.
Starch
plant version of sugar storage long chains of sugar molecules
glycogen
animal version of sugar storage molecule (big complex ball)
gastric juices
a digestive fluid secreted by the stomach
stomach
located just below the diaphragm, stores food and begins digestion of proteins(chemical digestion)
chyme
the mixture of partially digested food and digestive juices formed in the stomach
and you want it to be in contact with digestive system because you need to absorb all nutrients and can’t have it super acidic, so you add a base
What does protease do?
The exposed bonds are attacked by the second component of gastric juice—a protease, or protein-digesting enzyme, called pepsin
pepsin works best in a strongly acidic environment by breaking peptide bonds, it cleaves proteins into smaller polypeptides
Further digestion to individual amino acids occurs in the small intestine
What are the 2 components of gastric juices that carry out chemical digestion?
HCl and protease(an enzyme that digests proteins by hydrolysis) or pepsin
Where are the components of gastric juices produced? What are the 3 types of cells that secrete the components of gastric juices?
by cells in the gastric glands of stomach
- Parietal cells
- Chief cells
- Mucous cells
Parietal cells
Secrete H + and Cl- ions
Not HCl just the ions
Using an ATP-driven pump, they expel hydrogen ions into the lumen
The movement of hydrogen ions out of the parietal cell draws chloride out of the cell through specific membrane channels.
Though they arrive in the lumen by different routes, the secretion of hydrogen and chloride ions is chemically equivalent to secreting hydrochloric acid (HCl)
HCL unfolds proteins
Stretching them out revealing peptide bonds
Breaks things up
Chief cells
release pepsin into the lumen in an inactive form called pepsinogen(Folded up because you don’t want it to start digesting anything it comes across before it gets secreted
Don’t want the stomach cells that secrete to get damaged)
Once it reaches the lumen of the stomach HCl converts/breaks pepsinogen to pepsin
Unfolding it and converting to its active form
Pepsin starts dicing things up breaking molecular bonds
Pepsin also converts pepsinogen to pepsin
This is a example of positive feedback loop
A chain reaction
Both acid and pepsin break down pepsinogen to make more pepsin
Pepsin breaks peptide bonds after the acid unfolds them
Through these processes, both HCl and pepsin form in the lumen of the stomach, not within the cells of the gastric glands.
Mucous cells
Secrete mucus
Protects the stomach a lot blocks acid and enzyme from stomach lining
the parietal cells and chief cells both have one end coming in contact with lumen so this helps protect them
Not perfect things still get through it and that is why stomach lining is always regenerating
What would happen if HCl was produced in the parietal cells?
it would denature the proteins in the cells
but it doesn’t do that because it forms in the lumen
When do the contents of the stomach typically pass into the small intestine?
within 2–6 hours after a meal
What are accessory organs?
not part of the alimentary canal but play a big role in digestion
pancreas
liver
gallbladder
Pancreas
Makes pancreatic juice (enzymes and base)
Breaks things down, destroy proteins and base neutralizes the acid (HCl)
aids chemical digestion by producing an alkaline solution rich in bicarbonate as well as several enzymes
The bicarbonate neutralizes the acidity of chyme
the pancreatic enzymes are trypsin and chymotrypsin, proteases secreted into the duodenum in inactive forms In a chain reaction similar to activation of pepsin, they are activated when safely located in the lumen within the duodenum.
Liver
No digestion happens here
Produces bile (like detergent; mix of bile salts to break up fat/digestion and absorption of fat)
Involved in both forming fat molecules and indirectly breaking them down (by making bile salts)
Filters blood (via hepatic portal vein)
Package up extra higher energy molecules into/ Makes fat and glycogen for long term storage
Most of the nutrients that are absorbed in the small intestine pass through the portal vein into the liver and it sorts all these things deciding what is good to pass through the circulatory system what should be stored and converted into long term energy molecule what should be damaged if it is toxic it gets broken down or repackaged to get rid of it inactivate it and shoves down digestive system to get rid of
Constantly secretes bile
Gallbladder
Stores and concentrates bile to deliver into digestive tracts (the duodenum)
You can live without this
small intestine
longest part of the alimentary canal (6m long)
named because of its small diameter
the principal site of the enzymatic hydrolysis of food macromolecules and the absorption of nutrients.
duodenum
the 1st part of the small intestine where the chyme from the stomach mixes with digestive juices from the pancreas liver and gallbladder as well as gland from the cells of the intestinal wall
The epithelial lining is the source of several digestive enzymes
most digestion happens here in small intestine
where do digestion of fats and lipids begin
in the small intestine
How are different material absorbed in the small intestine ?
Some sugars; fructose; passively follow concentration gradients into epithelial cells (little fructose in body its small)
Other sugars; glucose; amino acids/ small peptides and vitamins are transported actively into epithelial cells (against their concentration gradient This active transport allows much more absorption of nutrients than would be possible with passive diffusion alone.)
Little ATP powered channels on the surface membranes of the intestines which use energy to pull these things in
Pass from epithelial cells into hepatic portal vein for filtering in liver
hepatic portal vein
A large vessel that conveys nutrient-laden blood from the small intestine to the liver, which regulates the blood’s nutrient content
From the liver, blood travels to the heart and then to other tissues and organs
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- it allows the liver to regulate the distribution of nutrients to the rest of the body. Because the liver can interconvert many organic molecules, blood that leaves the liver may have a very different nutrient balance than the blood that entered via the hepatic portal vein
- the arrangement allows the liver to remove toxic substances before the blood circulates broadly. The liver is the primary site for the detoxification of many organic molecules, including drugs, that are foreign to the body.
How are fats absorbed in the small intestine?
fats are insoluble in water so adaptations are need to digest and absorb them
Fat globules are broken into triglycerides by bile salts(too big to get through)
Triglycerides are broken into fatty acids and monoglycerides by lipase
They diffuse passively into epithelial cells
Once in intestinal lining cells they are repackaged into triglycerides (some glycerol and fatty acids pass directly into capillaries)
Huge polar molecule so can’t go anywhere on its own so, are coated with phospholipids cholesterol and proteins forming water soluble chylomicrons
chylomicrons Pass from epithelial cells via exocytosis into lacteals and transported by lymph(body fluid) to the heart for distribution
large intestine
The portion of the vertebrate alimentary canal between the small intestine and the anus; functions mainly in water absorption and the formation of feces
large intestine
The portion of the vertebrate alimentary canal between the small intestine and the anus; functions mainly in water absorption and the formation of feces
includes the colon cecum and rectum
Na+ is pumped out of the intestinal lumen into epithelial cells using ATP
Water follows by osmosis and we can reclaim all the water that was used in digestion
Bile pancreatic juice all have lot of water
colon
The largest section of the vertebrate large intestine; functions in water absorption and formation of feces
leads to rectum and anus
cecum
The blind pouch forming one branch of the large intestine important for fermenting ingested material, especially in animals that eat large amounts of plant material
Compared with many other mammals, humans have a small cecum
What are the functions of the ileum and jejunum?
function mainly in the absorption of nutrients and water
summarise the function of each of the four mammalian tooth types.
Insicors- biting
canines- tearing
premolar- grinding
molar- cutting
Outline the basic nutritional requirements animals obtain from their diets.
each animal has a suite of essential nutrients - molecules that the animal cannot produce & therefore must obtain from the diet
- essential amino acids
- essential fatty acids
- vitamins
- minerals
Categorize an animal’s diet based on the structure of its digestive tract.
gastrovascular cavity (digestive compartment with 1 opening): ex- cnidarians & flatworms
food vaculoes (cellular organelles in which hydrolytic enzymes break down food; are the simplest digestive compartments): ex; sponges
alimentary canal (a complete, digestive tract with 2 openings) ex; molluscs, annelids, nematodes, arthropods, echinoderms, chordates
What are the 3 primary ways ammonia can be removed?
- As ammonia (most aquatic vertebrates)
It’s a gas can easily transmit through things
If your a small animal like a flatworm this is easy to do because all you cells are on the outside - As urea eg; humans most amphibians some bony fish
Toxic but not as bad as ammonia
Can be safely stored in large quantities for long periods of time
Energy(ATP) cost in converting ammonia to urea
(You go to repackage ammonia molecule to urea molecule)
Water lost in urine (losing water when you get rid of urea)
Some animals go to great extents to stop water loss but when getting rid of urea you will lose water - As uric acid (most non- mammalian land animals)lizards and birds
Not to toxic
Can be safely stored almost indefinitely
Stored/ eliminated as solid— no water loss
Even higher energy cost in converting ammonia to uric acid
In shelled egg like bird eggs it accumulates in the egg
Why are excretory systems important?
These systems are central to homeostasis because they dispose of metabolic wastes and control body fluid composition.
secretion
The discharge of wastes from the body fluid into the filtrate.
Locate where these stages occur in the four types of excretory organs.
Capillaries are everywhere 1. Filtration in glomerulus; blood pressure pushes all these things out through the capillary walls into the bowmans capsule there it gets captured and sent to proximal tubule Water Cl HCO3- Amino acids Na+ K+ Glucose Urea
- Secretion in proximal tubule
Ammonia H+ toxins drugs
Things we want to get rid of
Actively push these things out into capillaries surrounding it
3.Recovery in proximal tubules Amino acids (100%) Glucose (100%) Water (65%) HCO3 - (90%) NaCl (65%) K
4.Recovery in descending limb
More water
5.Recovery in ascending limb
NaCl (25%)
Passive in thing segment active in thick segment (filtrate now very dilute)
6.Secretion in distal tubule:
H+ K+
7.Recovery in distal tubule
NaCl (5%)
More water and HCo3-
- Recovery in upper duct
- NaCl (5%) - Recovery in lower duct
Water (controlled by vasopressin) also called ADH antidiuretic hormone(controls how much water leaks on in lower part of collection tube) (here it is potentially very concentrated depending on state of hydration can close or open aquaporins; pores that let water through )
explain the protonephridium
eg; flatworms
Earliest nephron (machinery in kidney)
Flatworms have no circulatory system they don’t have blood pressure and cant push and they don’t have blood
Cellular units called flame bulbs cap the branches of each protonephridium.Cillia pull interstitial fluid into tubules where it is filtered
(Cellular Waste gets dumped through the cell membrane into interstitial fluid through body )
Filtrate travels through tubules and exits body wall via pores/ opening
theres many dispersed throughout the body not a single organ
has a low solute concentration, helping to balance the osmotic uptake of water from the environment.
explain Metanephridium
eg; earthworms
Similar to ours
Closed circulatory system
Have blood pressure to push things across membrane
Cilia pull in fluid from coelom
(In that liquid they push everything through the filtrate into tubules )
internal opening is in previous segment
Blood pressure pushes stuff into tubules things are reabsorbed back into the blood and what is left over accumulates into bladder as urine and then eliminated
Very similar to vertebrate kidney
In each segment (2 in each)
Have opening where it pulls liquid int from coelom
Each segment of a worm has a pair of metanephridia, which are immersed in coelomic fluid and enveloped by a capillary network. A ciliated funnel surrounds the internal opening. As the cilia beat, fluid is drawn into a collecting tubule, which includes a storage bladder that opens to the outside.
As urine moves along the tubule, the transport epithelium bordering the lumen reabsorbs most solutes and returns them to the blood in the capillaries. Nitrogenous wastes remain in the tubule and are excreted to the outside
Their metanephridia balance the water influx by producing urine that is dilute (hypoosmotic to body fluids).
explain Malpighian tubule
(in insects)
Most different
Don’t have closed circulatory system - No liquid is pushed through a filtration membrane
Don’t filter anything across
Waste materials are actively transported into tubules from hemolymph (blood)
Malpighian tubules permeate through the body cavity and hemolymph surrounds the tubules and materials are transported into the tubules water follows following concentration gradient
Waste is combined with dietary waste
Wate and important solutes recovered in rectum(just like other system)
They don’t have urine all is combined with digestive waste
The filtration step common to other excretory systems is absent. Instead, the transport epithelium that lines the tubules secretes certain solutes, including nitrogenous wastes, from the hemolymph into the lumen of the tubule. Water follows the solutes into the tubule by osmosis, and the fluid then passes into the rectum. There, most solutes are pumped back into the hemolymph, and water reabsorption by osmosis follows. The nitrogenous wastes—mainly insoluble uric acid—are eliminated as nearly dry matter along with the feces. Capable of conserving water very effectively,
i
Osmolarity increases with increasing depth
Transport is passive when following gradient
Active when against
Kidney is most energetically expensive organs in the body
renal cortex and medulla
supplied by blood by renal artery and drained by renal vein
Metabolic rate
rate of energy consumed (amount of energy consumed by your body)
How much energy your body is burning at any given food
Basal metabolic rate
rate of energy consumed when not doing anything
Looking at the wall doing nothing
1500 kcal/day depending on body size
A marathon burns 3000 kcal
What do cnidarians and flat worms have?
any animals with relatively simple body plans have a digestive compartment with a single opening
This pouch, called a gastrovascular cavity, functions in digestion as well as in the distribution of nutrients throughout the body (hence the vascular part of the term).
What do sponges have?
food vacuoles
What do all other animals have?
All the others have an alimentary canal (a complete digestive tract with 2 openings)
All animals with a complete digestive tract have specialized regions so that different things can happen simultaneously
Why does food need to be broken down?
So that it can pass through membranes and into blood stream so that your body can move the food around
Simple columnar epithelium (lines intestines)
Good at moving things back and forth
Macromolecules are too big to pass through (big piece of starch)
They’re necessarily not the right macromolecules anyway
Ex; if you eat cholesterol from steak that’s cow cholesterol not human so that’s not the same thing, so we need to break it and put it back together into human form
Blood
From renal artery heading into liver (all blood is delivered to liver through here)
Afferent arteriole
Go into glomeruli
Glomerulus
With in Bowmans capsule
Blood vessels are super convoluted in here
Efferent arteriole
Peritubular capillaries or vasa recta (intertwine with loop of henle)
Renal vein
Pressurized filtration occurs in glomerulus
Blood is pressurized Because we have closed circulatory system pushes all these things across the membranes in the capillaries
In glomerulus tiny blood vessels providing lots of surface area so blood pressure inside of these pushes stuff out
