Lecture 7 Flashcards
what are the 3 processes of animal nutrition?
-ingestion
-digestion
-absorption
what are the 3 main types of feeding strategies?
-herbivores
-carnivores
-omnivores
what are herbivores?
-animals that eat mainly autotrophs (plants + algae)
what are carnivores?
-animals that eat other animals
what are omnivores?
-animals that regularly consume animals as well as plants or algae
what is another type of feeder? what do they feed on?
-opportunistic feeder
-eat foods outside their standard diet when not available
what is an unavoidable supplement in an animals diet?
-microorganisms
what does an animals diet provide? what happens to this and what is it used for?
-provides chemical energy that is converted to ATP
-powers body processes
what must animals have a source of in order to construct organic molecules?
-organic carbon
-organic nitrogen
what is required by animals cells?
-essential nutrients
what are essential nutrients? where are they obtained?
-molecules that an animal cannot produce
-must be obtained from dietary sources
what are the 4 classes of essential nutrients?
-essential amino acids
-essential fatty acids
-vitamins
-minerals
how many amino acids do animals require? how many can they synthesize from molecules in their diet?
-require 20
-can synthesize about half
how do animals synthesize some amino acids?
-using enzymes
-also need sulphur and organic nitrogen from their diet
what is malnutrition?
-protein deficiency
-a diet that provides insufficient essential amino acids
what will provide all essential amino acids? what type of proteins are these?
-meat, eggs, and cheese
-complete proteins
how do herbivores recieve their essential amino acids? what type of proteins are these?
-specific plant protein combinations
-incomplete proteins
can animals synthesize any fatty acids on their own? what are the ones they cannot synthesize? why can’t they?
-YES, can synthesize most of them
-cannot synthesize certain unsaturated fatty acids
-cannot make the specific double bonds for them
are the non-essential fatty acids as important as the essential ones?
-YES
-used to build cells
is it possible to have deficiencies in fatty acids?
-yes but it is rare
what are vitamins? what are their features?
-organic molecules required in the diet in small amounts
-have diverse functions
-many function as coenzymes
what are coenzymes? what vitamins typically function as them?
-required by enzymes for the catalysis of a chemical reaction
-B vitamins
how many vitamins are essential to humans?
-13
what are the 2 categories of vitamins?
-fat soluble
-water soluble
what category of vitamins can be toxic in excess?
-fat soluble
what vitamin varies in its need? why does it vary?
-vitamin D
-can be synthesized
what are minerals? what are their features?
-simple inorganic nutrients
-typically required in small amounts, but depends on the organism
-excess can affect homeostasis
-variety of functions
-function as an enzymes cofactors (nonprotein helper molecules)
what is undernourishment?
-the result of a diet that consistently supplies less chemical energy than the body requires
what will an undernourished individuals body do?
-use up stored fat and carbohydrates
-break down its own proteins
-lose muscle mass
-suffer protein deficiency of the brain
-die or suffer irreversible damage
what is malnourishment?
-the long term absence of one or more essential nutrients from the diet
what can malnourishment cause? how can it be corrected?
-cause deformities, disease, and death
-can be corrected by dietary changes
what is epidemiology?
-the study of human health and disease in populations
-gives insights into human nutrition
what has been found to stem from a deficiency of folic acid in pregnant mothers?
-neural tube defects
how do digestive systems of vertebrates differ among eachother?
-have variations based on a common plan (variations often are related to diet)
-dentition (their assortment of teeth)
-stomach + intestinal adaptations
what type of variation is an animals dentition?
-structural variation reflected on their diet
what are examples of animals variations in dentition?
-mammals have varying specialized dentition adapted to their usual diet
-poisonous snakes teeth are modified to fangs for injecting venom and they can unhinge their jaws to swallow prey whole
how are vertebrates digestive system length and diet correlated?
-herbivores + omnivores have longer alimentary canals b/c vegetation takes longer to digest
why does vegetation take longer to digest?
-cell walls are present (takes more time and energy to break)
how are stomachs of carnivores different?
-they have large expandable stomachs b/c they may go a long time between meals
what is found within the human digestive system (and other animals)
-many bacteria to help produce nutrients
-diverse gut microbiome
what is a gut microbiome? what is its purpose?
-collection of bacteria
-help with chemical breakdown to produce vitamins
-regulate development of epithelium
-immune system function
-can be analyzed and used in diagnostics
what is present in many herbivores to help break down cellulose into simple sugars?
-fermentation chambers
-symbiotic (living within) microorganisms digest the cellulose into simple sugars
what is coprophagy?
-animals that eat their own feces
where is mutualistic bacteria present in rabbits and some rodents? how do they respond to this?
-live in the large intestine + cecum
-most nutrients are absorbed in the small intestine, but nutrients made by bacteria are lost
-feed on feces to pass it through the alimentary canal a second time
where is mutualistic bacteria located in most other animals?
-cecum
where have the most elaborate adaptations for herbivores evolved? what is this adaptation?
-in ruminants
-multiple stomach chambers
what are ruminants?
-cud-chewing animals
-ex: sheep + cattle
how do giant tube worms receive nutrients? why do they receive them this way?
-obtain nutrients solely from mutualistic bacteria
-have no mouth or digestive system
what are the 4 basic phases of urine formation?
-input in the renal artery
-glomerulus filtration in the bowman’s capsule
-tubular reabsorption and secretion in the renal tubule
-water conservation in the collecting duct
what is the first step to urine formation?
-filtrate is formed when fluid passes from the bloodstream to the lumen of the bowman’s capsule (glomerulus)
-bowman’s capsule capillaries are permeable to water and small solutes
what occurs in the proximal tubule during the second step to urine formation?
-reabsorption of ions, water, and nutrients occurs in the proximal tubule
-molecules transport actively and passively from filtrate -> interstitial fluid -> capillaries
-some metabolic waste is secreted into filtrate
does filtrate volume increase or decrease once it finishes in the proximal tubule?
-decreases
what does the proximal tubule help maintain?
-body fluid pH
what occurs in the descending loop of henle during the second step to urine formation?
-water reabsorption continues through aquaporin protein channels
what is the movement driven by in the descending loop of henle?
-high osmolarity of the interstitial fluid (hyperosmotic to the filtrate) causing water to move back
-will gain more osmolarity as it dips into the medulla
what happens to the filtrate in the descending loop of henle?
-becomes more concentrated due to the loss of water
what is a feature of the ascending loop of henle that is critical to its function?
-salt but not water can diffuse from the tubule to the interstitial fluid
what happens to the filtrate in the ascending loop of henle?
-filtrate becomes more dilute (active transport within its thicker section)
what occurs in the distal tubule? what does this contribute to?
-K+ and NaCl concentrations of body fluids are regulated
-contributes to the pH regulation
what happens in the third step of urine formation?
-the collecting duct carries filtrate through the medulla to the renal pelvis
-water is lost + some salt + some urea
-filtrate is more concentrated
-urine is hyperosmotic to body fluids
what determines urine concentration?
-hormonal control of the permeability and transport of ions and water
what is a key terrestrial adaptation in terms of urine formation?
-the ability of a mammalian kidney to conserve water
-urine is much more concentrated than blood
-4x in humans and 25x in australian hopping mice
what is cooperative action?
-active transport of solutes against concentration gradients
what are the 2 things largely responsible for the osmotic gradient that concentrates urine?
-cooperative action
-precise arrangement of the loops of henle and collecting ducts
what 2 solutes contribute to the osmolarity of interstitial fluid? what does this cause?
-NaCl + urea
-causes water reabsorption in the kidney which concentrates urine
what leaves the proximal tubule?
-HCO3
-NaCl
-K+
-water
-nutrients
what enters the proximal tubule?
-H+
-NH3
what leaves the descending loop of henle?
-water
what leaves the ascending loop of henle?
-NaCl
what leaves the distal tubule?
-NaCl
-HC03
-water
what enters the distal tubule?
-K+
-H+
what leaves the collecting duct?
-NaCl
-urea
-water
does the filtrates osmolarity change in the proximal tubule?
-no it remains the same
what helps maintain a high salt concentration in the kidney? what does it allow?
-the countercurrent multiplier system in the loop of henle
-allows the vasa recta to supply the kidney with nutrients while not affecting the osmolarity gradient
what are the vasa recta?
-branches of terminal arteries
how is the ascending loop of henle able to perform active transport?
-considerable amount of energy is expended to maintain the osmolarity gradient between the medulla and the cortex
what will be related to the osmoregulation requirements in an animals habitat?
-the form and function of the animals nephrons (various vertebrate classes)
what type of nephrons are present in mammals?
-juxtamedullary nephron
what type of effect does the juxtamedullary nephron have? what does it contribute to? give an example.
-urine concentrating effect
-contributes to water conservation
-desert animals have loops extending deep into the medulla as they have the most hyperosmotic urine (to conserve water)
how do long loops of henle help animals?
-long loops maintain steep gradients
how do the lengths of loops in dry environment animals relate to the length of loops in freshwater environment animals?
-dry environment animals have long loops
-freshwater environment animals have short loops
how do birds conserve water?
-have shorter loops, but excrete uric acid (paste) instead of urea to conserve water
what kind of nephrons do most reptiles have? how do they conserve water?
-cortical nephrons
-water is reabsorbed by epithelium in the chamber where urine and feces exits the body
-also excrete nitrogenous waste as uric acid
how do freshwater fishes conserve salt?
-conserve salt in their distal tubules
-excrete large volumes of dilute urine b/c they must excrete excess water continuously
how is the kidney function of amphibians?
-similar to freshwater fishes
-conserve water on land by reabsorbing water from the urinary bladder
how do marine bony fishes function in osmoregulation?
-gain excess salts from surrounding causing them to lose water
-hypoosmotic to their environment
-excrete little urine
-smaller nephrons without a distal tubule
