lecture 4 animal Flashcards
why do animals eat
all physiological functions require energy (chemical, atp) and/or matter – carbon skeletons to build various structures
– all animals are heterotrophic, the consome other organisms for food
bioenergetics
overall flow and transformation of energy within organism
basic overview of bioenergetics
– organic molecules in food enter through consumptopon – digestion absorption – energy lost in form of heat and in feces – nutrient molecules in body cells – energy lost in nitrogenous waste (urine) – cellular respiration – heat loss – atp – ceullular work heat lost – and viosysntheis heat is lost
biosynthesis
making new things in body with building blocks (carbon skeletons) – growth, repairing, storing, gamete productioin..
how much energy does an animals need?
enough to maintain basic metabolic function – maintain cellular activity, blood flow, respiration, temperature – very minimum amount
the more active animal is, more energy is needed
metabolic rate
amount of energy used per unit time – what dictates amount of energy youre going to need
basal metabolic rate (BMR)
metabolic rate of NON-GROWING endotherm that is AT REST, has an EMPTY DIGESTIVE TRACT, and is NOT EXPERIENCING STRESS – minimum amount of energy to maintain basic functions
what could you measure to determine animals energy use
heat production, oxygen consumption, carbon dioxide production (respiration) , food consumption/waste production
what does metabolic rate depend on
activity, size and unit/body mass
metabolic rate depends on activity – examples
measuring resting metabolic rate of juvenile sea lion – not basal because it is still growing
physiologists also interested in how much energy is being used – mseasuring energy of flight in a bird – measuring energy of swimming in a shark
metabolic rate depends on size examples
elephants have a higher ABSOLUTE BMR – which means they need more food overall than a mouse
metabolic rates depends on unit/body mass
elephants have a LOWER BMR than mouse for each Kg because mouse is consuming more O2 per kG than elephant – mouse eats more per unit body mass but elephant eats more in absolute terms``
what three things must an animal’s diet supply
energy, organic molecules, and essential nutrients
chemical energy in food..
used in cellular respiration to produce ATP or is stored
organic molecules are..
needed for biosynthesis (building blocks of our tissues..) ex: nucleic acids, carbohydrates, proteins, lipids
essential nutrients
things our body cannot produce on its own – amino acids, essential fatty acids, vitamins, minerals (vitamin C or calcium)
what functions are carried out by digestive systems
- ingestion (bringing food to mouth– food handling)
- digestion (break down of food into absorbable components
- absorption (nutrient molecules enter body cells)
- elimination (removeal of undigested material)
ingenstion
bring food to mouth
digestion
in mouth starts to both chemically and mechanically digest food (chemically = amylasy, mechanically = chewing)
absorption
once broken down into small enough pieces, have to absorb food in body cells (intestinal area)
elimination
get rid of undigested molecules
structures associated with ingestion are the most diverse part of the digestive system, why
differences in diet, herbivores vs carnivores – carnivores are usually chewing softer – herbivores – plants are harder – diff sizes, shapes of teeth
– huge variety of sources of food therefore animals have EVOLVED STRUCTURES that a;llow trhem to eat these various foods.
mammalian teeth reflect diet
herbivore: intense premolars and molars to grind down plant bits (cows)
carnivores: enlarged icisors and canines for gripping and shredding the animal theyre preying (lions, wolves)
omnivores: a little bit of everything – specialized on broader sources of foods (humans)
four main feeding mechanisms
– suspension feeders and filter feeders
– substrate feeders
– fluid feeders
– bulk feedersq
suspension and filter feeders
whale with baleen structure that is comb like – takes big gulp of water containing krill, squishes water out so that only krill remains in mouth and swalls.
subtstrate feeder
animals that livw on the food they consume – caterpillars live on leaves, they eat those leaves
fluid feeders
mosquitos have specialized mouth parts to pierce the host in order ot drink its blood
bulk feeder
majority of animals – tend to feed at large amounts of time (pithon)
what two parts is the digestive system made up of
alimentary canal and accessory organs
alimentary canal
tube from mouth all the way to anus
– oral cavity
– pharynx
– esophagus
– stomach
– small intestine
– large intestine
–rectum
–anus
accessory organs
salivary glands, gall blader, pancreas, liver
digestive system is specialized for..
sequential stages of food processing (certain parts of food get processed on way at one part of system and anothewr way at another part.
food is pushed along by
peristalsis
peristalsis
contraction and relaxation that oushing food down alimentary canal
sphincters between compartments
closes off sections while something is happening – squeezes shut until ready to recieve food
the oral cavity is the first site of
mechanical and chemical digestion
what do salivary glands produce
saliva
saliva contains
mucus, buffers, antimicrobial agents, salivary amylase
mucus
protects lining of mouth and lubricates food
buffers
help prevent tooth decay by neutralizing acid
antimicrobial agents
lysozyme – protects your body from any bacteria in food
salivary amylase
enzymatic breakdown of carbohydrates
from outh to stomacvh:
swallowing reflex and espohageal peristalsis
pathway of food
- tongue manipulates food into ball
- ball of food is called bolus
- tongue pushes bolus down the pharynx
- uh oh! epiglottis is up – it has to go down to prevent food from going to the lungs
- at this time tyhe sphincter is contracted because no food is emerging and it is not ready to let it pass
- once epiglottis is down, food is pushed down, sphincters relax allowing food to pass down into stomach
- through peristalsis (wave of action) food is being transported down esophjagus to the stomach (relaxed sphincter allows food in stomach)
digestion in the stomach
mechanical and chemical digestion continues
– epithelium (lining of stomach) secretes gastric juice
– in stomach food bolus and gastric juice mix and become chyme
gastric glands have three speciallized types of cells
mucous cell, chief cell, parietal cell
mucous cell
protects lining of stomach – makes sure digestive enzyme are not autodigesting own stomach
chief cell
hormones from endocrine ststem triggers chief cells to release pepsinogen
parietal cell
endocrine etriggers parietal cells to release H+ and Cl- which form HCl in lumen of stomach
what are three things HCl does in stomach
kills bacteria, starts to breakdown materials (not fully)
and can be used to trigger pepsinogen to become pepsin
pepsinogen
is inactive meaning it is not capable of breaking down anything – it needs to become pepsin in order to break down protein
pepsin
is important because it is responsible for breaking down and digesting proteins
what is pepsin an example of
positive feedback loop – if you have a little bit of pepsin being produced this can trigger more production of pepsinogen into pepsin until meal is fully digested
the location ofg chemical digestion varies between nutrients – table q
[oral cavity, oharynx, esophagus: only carbohydrates – amylase]
[stomach : only protein (pepsin)]
[small intestine: pancreatic enzymes: all (carbs, lipids, nucelic acids, proteins) – only small pieces of lipids]
[large inestine: epithelial enzymes all but lipids]
role of liver in chemical digestion
pancreatic enzymes cant digest really big pieces of lipids – hose big pieces need to become smaller – we do this through production of bile through the liver
liver produces bile – gall bladder stores the bile – bile is released into small intestine to make fast smaller and smaller to digest
how do we not digest ourselves
– mucus provides protection for the cells lining alimentary canal
– HCl an digestive enzymes remain inactive until needed
–rapid turnover of cells – little bit of self digesting but constantly fixing/repairing aliimentary canal
the structure of small intestine is well sutited for
digestion and absoprtion
– provides large surface area– has large circular folds – on folds have smaller folds called villi, and even on villi have smaller smalller folds called microvilli
basic rundown of absorption small intestine
nutrients are absorbed through lining of intestine and into various blood vessels (beins) that carry blood to the nutrients to liver – liver decides where they go and redistribute them throughout body (EXCCEPT FATS)
where do fats go if nutrients go to liver
lymph vessels to the lymphatic system
liver regulates
redistribution of nutrients to rest of body
structure of intestine summary and function
large surface area:
- large narrow tube
- large circular folds
- villi
-microvilli
– many blood vessels connecting with small intestine carring nutrients to liver
- liver regulates distribution – functions in detoxification – things toxic will go where can be waste products
the large intestine is composed of
colonm cecum and rectum
– attached at small intestine – go up thats colon, go down (to sort of dead end) is cecum
whats cecums function
in fermenting ingested plants – has symbiotic bacteria to help w digestion of plants
cecum size herbivore vs carnivore
cecum is larger in herbivores bc they eat more plants and need more help digesting htme
size of alimentary canal herbivore vs carnivore
herbivores larger because digestion of plants takes more time - why its longer
what is colons function
in water reabsorption and formation and elimination of feces
where is majority of water reabsorbed
small intestine q
feces cosnist of
undigested material and bacteria (why we wash our hands after using bathroom)
secretion of digestive hormones is triggered by
presence of food
what do digestive hormones trigger
secretion of gastric juices and digestive enzymes
what two hormones regulate ENERGY storage
insulin an glucagon
insulin
causes excess energy to be stored as glycogen in liver and as fat in adipose cells
glucagon
secreted during lack of energy – breakdown of liver glycogen into glucose
a satiety center in the brain,.
generates the nerve impulse that makes us feel hungry or full
which hormones regulate appetite
leptin, insulin, peptide YY, ghrelin
leptin
produced by adipose and regulates long term appetite - how we feel full long term
insulin and peptide YY
secreted in response to eal (when you have had food(full)
ghrelin
secreted when stomach is empty (hungry)
obesity and evolution
grey seals have evolved a PERIOD of obesity cxritical to EARLY survival – so if it wasnt for their obesity, they wouldnt survive juvenile stage
– pups spend 3 weeks nursing on high fat milk – remain on land for several weeks because of blubber – learns how to survive on land – lives of blubbver
