Respiratory and Digestive Systems Flashcards
Respiratory system
Delivers O2 to tissues and removal of CO2, exchange of gases across membrane
Open system
External vs internal respiration
External is gas exchange between environment and blood
Internal is gas exchange between blood and tissues
Ventilation
Act of moving environmental medium that O2 and CO2 are being exchanged with water or air
Apnea vs perfusion ventilation
Apnea actively ceasing the movement of media
Perfusion is pumping blood through capillaries
Ficks law of diffusion
Rate = kA(p2-p1)/D
Partial pressure vs concentration
partial pressure changes with altitude while concentration in constant
For high rate of diffusion (4)
high partial pressure difference, high surface area, low wall thickness, and wet surface
cutaneous respiration
breathing through skin, mostly seen in small organisms, common in amphibians
gills
dense capillary beds in the branchial region of the head, gas exchange occurs between water and capillaries
external gills
protrude out into the water, found in most amphibians and larval vertebrates, often have muscle at base that allow for gills to be waved back and forth
internal gills
associates with pharyngeal slits,
supported by branchial arches,
blood fed by aortic arches, covered in bony shields called operculum
gill structure
primary lamella branch from branchial arches and support secondary lamella
secondary lamella house capillary beds that exchange gas with water
afferent and efferent arteries in branchial arch
how do gills increase surface area?
have lots of tiny folds
why is ventilation key
blood moving through capillaries is constantly being replaced by new deoxygenated blood
water must be moved over the gills at a constant pace to keep exchange going
cilia
microscopic hair-like organelles found in anatomical systems, beating over cilia, create small scale flow that brings water over respiratory surfaces
ram ventilation
fish create movement over gills by opening their mouth as they swim
dual pump
2 pumps- buccal and opercular result in almost continuous unidirectional flow across the gills
dual pump structure
gill curtain lies between buccal cavity and opercular cavity
oral valve is mouth opening
opercular valve is creates by opercular flap over the gills
dual pump phases
suction phase: opercular valve is closes, orval valve is open, both cavities expand causing water to flow
force: opercular valve opens, oral valve closes, buccal and opercular cavities are compressed (pushing water across gills)
countercurrent exchange
water and blood move in parallel opposite directions so there is constant exchange
basic anatomy of lung
deformable bags in the thoracic cavity, covered in epithelial cells to allow the gas transfer, connect to the environment via the trachea, glottis muscle opens and closes the entrance to the trachea, trachea branch into brachial, bronchi divide into bronchioles
swim bladders
air-filled sacs in fish that fulfill both respiratory and hydrostatic functions help maintain buoyancy
swim bladder vs lung
swim bladder located more dorsal to digestive tract
swim bladder is usually single sac
blood from swim bladder does not return to the heart
respiratory gas bladder is swim bladder that aids in supplementary gas exchange
physoclistous bladders do not maintain connection to pharynx to fill with air
physoclistous bladders
O2 fed to swim bladder via gas gland
rete mirabile feeds blood to gas gland
oval removes O2 and is controlled by smooth muscle
rete mirabile
cluster of capillaries that feed blood to the gas gland and allow absorption of oxygen
faveoli in lungfish
pair of lungs fed by trachea from esophagus
walls of lung covered in septa
septa create faveoli
faveoli open the main chamber of the lungs
faveoli
compartments created by septa that increase surface area
faveoli in reptiles
on the surface of the lungs, controlled by smooth muscle
alveoli
air sacs which act as focus (and only place) of gas exchange in mammalian lung, capillaries surround cluster of alveoli at end of bronchiole trees, alveoli have greater SA with branched compartments
mammalian respiratory tree
respiratory channel is divided creating tree like structure- trachea, bronchi, and bronchioles, branches terminate into comparments called alveoli where gas exchange occurs
ventilation muscular pumps
dual pump
buccal pump
aspiration pump
buccal pump
In fish
two stroke pump- mixes old and fresh air
four stroke pump- requires twice the number of movements of single cycle
two stroke pump vs four stroke pump
two stroke (amphibians): has expansion to draw air in then compression to expel air
four-stroke (air breathing fish): has inhalation phase (intake then pushed into lungs) and exhalation phase (old air moves to mouth then expelled to air)
aspiration pump
separates feeding mechanism from the respiratory system
bidirectional movement of air
lung within pump, and size is manipulated by musculature
muscles open chest to pull air into lungs and compresses to move air out
mammalian ventilation
comes from movement of ribcage
during inhalation external intercostalis muscles between ribs pull ribcage in and diaphragm contracts
during exhalation internal intercostalis muscles pull ribs inward and diaphragm relaxes
ventilation and locomotion
when limbs contact the ground it shifts the ribcage
viscera move back and forth during locomotion pushing diaphragm and lungs in rhythm
lungs in snakes
have elongated single lung
bird lungs
no avleoli at end of bronchiole passages
air passage in one way path and divide into parabronchi lined with air capillaries
air flow in birds
inhalation: trachea to posterior sac, air in lungs enters anterior sac
exhalation: posterior sac to lungs, anterior sac air pushed out, air leaves trachea
cross current
blood and medium flow perpendicular to each other
the constant partial pressure difference between blood and air
uniform pool
air flows into chamber then is expelled
air is constantly replaced maintaining partial pressure
blood in capillaries is the same partial pressure as oxygen
digestion
breakdown of food items into nutrients, chemical and mechanical
absorption
uptake of nutrients
elimination
removal of waste
boundaries of buccal cavity
oral openings is entrance to buccal cavity from environment
lips form margins (normally at back end of tooth row)
mammals have cheeks that hold food (lips meet near front)
primary palate
roof of mouth made from ventral skull bones, formed from dermal bones, in some fish and tetrapods openings allow for nasal passages to connect to mouth
secondary palate
separates the mouth from nasal passages, lateral bones in crocodiles and mammals fold and meet at the midline, underneath primary palate, divided into hard (front) and soft (back)
old mouth vs new mouth
old mouth: buccal cavity lies in front of branchial arches, has mouth and prominent cheeks
new mouth: front arched evolve into jaws and move forward, making grasping prey easier, original cheeks reduced, buccal cavity now behind jaws
teeth in vertebrates
teeth are hard elements used to capture and break down food
outside in: teeth evolved from dermal armor
inside out: teeth evolved from elements in the pharynx
hard components of vertebrate tooth
enamel: hardest substance in the body, caps tooth
dentin: same composition as bone but harder, continuously grows throughout life, fills most of pump cavity
cementum: grows on the surface of the roots
periodontal ligament: thick bundles of collagen that connect to cementum to mandible
define/explain homodont, heterodont, polyphyodont, and diphyodont
homodont: teeth are identical across the mouth
heterodont: teeth wary across the mouth
polyphyodont: constant replacement throughout life
diphyodont: two sets of teeth (mammals), deciduous are those that appear early, and permanent are the second set
mammalian teeth
incisors: front
canines: elongate cones
premolars: along sides of the mouth
molars: back teeth used for hard chewing
dental formula
shorthand for set of teeth in a specific mammal, only uses one side of the mouth and separates into upper and lower
tongue
muscular organ in tetrapods used for manipulation food for chewing and swallowing
derived from hypobranchial musculature attached to hyoid apparatus
hyoid apparatus
derivative of the hyoid and branchial skeleton
tongue functions
mammalian carnivore tongue is covered in filiform papillae (spiny projections) like a file to scrape flesh from bone
papillar use to clean fur, tongue also used for drinking via lapping motion that utilizes fluid inertia to lift liquid to the mouth
lingual feeding
involves using the tongue to capture prey outside the mouth, projectile tongue, use the tongue as a probe
pharynx in other mammals vs humans
in other mammals there are 3 seals during chewing (lips, tongue against soft palate, and epiglottis against soft palate)
humans lost the third seal, and the pharynx is elongated to accommodate speech
pharynx
Represents boundary of buccal cavity and alimentary cavity
food is forced from the buccal cavity to pharnyx then esophagus
tooth growth
initially develop beneath the skin as derivatives of epidermis
when fully mature teeth erupt though skin and enter buccal cavity
mammals permanent teeth form next to baby teeth but deeper in jaw, as the grow they compress baby teeth, cutting off their nutrient supply
why focus on teeth?
direct link between anatomy and ecology
insight into evolutionary and ecological history
filter feeders
filter small organisms or particles from the water requires a moving current that can be active or passive
mass feeders
seize and manipulate chunks of food
involve swallowing food whole
many break larger food items using moth and dental structures
stiff/ brittle materials
once critical load/ stress is achieved all energy is released into fracture formation
the tools has to provide sufficient load to material for it to break without also breaking tool
tough/ ductile materials
energy applied can create fracture but this will deform if the stiffness is too low
tough materials prevent fracture by deforming easily dissipating the energy applied
sharpness
force is applied over a small enough area to cause little deformation
teeth for crushing hard foods
tend to be broad and rounded
create force to overcome stress of food without reaching its own critical stress
fracture in teeth
damage to enamel can cause chip at point of contact of tooth and food
enamel dentine junction (EDJ) is dangerous and cracks can cause the entire enamel cap to fail
tufts
intrinsic defects in the enamel localized at the EDJ
hypocalcified fissures that acts as areas of weakeness for cracks to form, stress spreads across reducing growing crack
Huneter Schreger bands
areas of enamel where the prismatic structure is woven like fabric
cutting highly deformable materials
angled blade adds a slicing action to the downward movement
notched blade is angled meeting at the vertex, holds deformable material in place while slicing
Parts of alimentary canal
Esophagus, stomach, small intestine, large intestine, rectum and anus
Accessory organs
Salivary glands, liver, gallbladder, and pancreas
Structure of alimentary canal
Musca: innermost layer
Submucosa: loose connective tissue and branching nerves
Muscularis externa: sheets of smooth muscle oriented both along the length of tube
Serosa: fibrous connective tissue and surrounding messentery
Structure of mucosa
Epithelium: tissue that lines the lumen of tube
Muscularis mucosae: thin layers of smooth muscle fibers, controls movement of folds
Lamina propia: loose tissue in between that contains blood, white blood vessels, and lymphatic vessels
peristalsis
muscles are antagonistic to each other and drive motion, outer contracts above food while lower contracts behind food, pushing food down
movement of food by muscles in esophagus
stomach
chemical digestion on proteins
when no food is present, walls collapse in folds-rugae
stomach lining
glandular epithelium lines stomach and is covered in gastric glands within gastric pits
glands have chief, parietal and mucoid cells
gastric cells and what they do
chief cells store protein dissolving enzymes
parietal cells sore acid that activates enymes
mucoid cells secrete mucus that protect the epithelium from acid
regions of stomach
cardia: found only in mammals, connects esophagus to rest of stomach
fundus: is largest region, glands have mucus, parietal and chief cells
pylorus: region right before stomach empties into intestines, mucus neutralizes acid before material is moves to intestines
small intestine
receives food from the stomach, uses peristalsis to move through the system, continues digestion and absorption
small intestine structure
epithelium walls heavily folded, villi increase surface area, capillary beds enter villi, these eventually lead to hepatic portal system
microvilli on walls of villi that increase surface area
sections of small intestines
duodenum: short, continues digestion from stomach, uses bile for gallbladder, liver, and pancreas
jejunum: primarily absorbs carbohydrates, amino acids and fatty acids, surface area increases
Ileum: longest portion, absorbs what remains and reabsorbs bile acids
large intestines
lack villi, form a loop called the colon, compacts remaining material, and removes water, if the end of the intestines connects with urinary tract-cloaca, the rectum excretes waste via the anus
types of glands
exocrine gland: have ducts that collect product to carry it away
endocrine gland:product is carried away by circulatory system
unicellular: single secretory cells
multicellular: many secretory cells in aggregate
oral glands
secrete mucus and fluid using common duct
lacrimal (harderian): bathes eyes keeping them moist
Duvernoy: found behind the eye in snakes
salivary glands in mammals
zygomatic gland: in carnivorous mammals under orbit
salivary glands excrete saliva with mucus, salts, proteins and enzymes, amylase digests starch
pancreas
exocrine function: excrete digestive enzymes (amylase,lipase, trypsin) to duodenum
endocrine function: secrete hormones like insulin and glucagon
liver anatomy
composed of sheets of hepatocytes separated by sinuses
arteries carry fresh blood to oxygenate liver
hepatic veins bring nutrients and toxins from digestive system
liver functions
glandular cells excrete bile that is stored in the gallbladder
bile emulsifies fat, breaking it down into small droplets to ease digestion
spiral valves in fish
corkscrew surface on the inside of the intestines
teleosts have coiled intestines instead
gizzard
muscular regions of the stomach that grind food against ingested objects to aid in mechanical digestion
glandular region of the stomach comes before the gizzard
2 part stomach of birds
proventriculus is where digestive enzymes are secreted
gizzard is the second muscular stomach (collects grit)
gastroliths
gizzard stones that must be different from other rock around it, smooth and associates with a fossil
crop
expanded muscular pouch in esophagus that stores food and bacteria for fermentation
digestion issue with eating grass
grass is major energy source but no vertebrates can manufacture cellulase
symbiotic microorganisms live in the alimentary canal to digest cellulose- this is fermentation
foregut fermentation- ruminant stomach
ruminants: mammalian herbivores with extremely specialized stomachs
rumen/ reticulum: microbes in chamber break down cellulose into glucose
omasum: water and minerals absorbed
abomasum: corresponds to stomach
foregut fermentation- ruminantion (digestion +regurgitation)
grass is mixed with saliva and swallowed into rumen
contractions in reticulum mix digestive juices with material in rumen
material is regurgitated in 3 steps:
1. diaphragm is contracted (trachea kept closed)
2. aspiration sucks material into esophagus
3. peristaltic contractions bring material into mouth
foregut fermentation- omasum and abomasum
omasum absorbs fatty acids and water and acts as a barrier between fermenting chamber and an acidic stomach
abomasum acts as a typical mammalian stomach
cecum
sac like structure attached to large intestine, houses microbes that digest cellulose, related to human appendix
foregut vs hindgut fermentation
foregut happens early in digestion allowing thorough digestion of cellulose (might lose nutrients since fermented before intestines), allows for rechewing and mechanical breakdown
hindgut has material pass through regular system first allowing normal digestion, faster than foregut fermentation
salt glands
saltwater is problematic for tetrapods
excrete water through salt glands instead of flushing through kidneys
amphibian glands
mucus (serious) glands: excrete mucus that aids that aids in respiration, reproduction, thermoregulation and defense
granular (venom) glands: excrete toxins of various types
bufotoxin
cane toad secretes the toxin when agitated/ threatened
poison dart frogs
family dendrobatidae, secrete batrachotoxin from venom glands
venom
venom gland in venomous slankes injects venom by homolog of duvernoy’s gland
stored in englarged gland, compressor grandilae muscle compresses gland
contains mix of toxins and digestive enzymes
ulcers
open sores that develop in lining of stomach and upper small intestine
mucosa is eaten away leaving break in membrane
cause of ulcers
H. pylori bacteria that live in mucus layer that protects the stomach and intestinal lining from acid
bacteria produces compounds that damage epithelial cells and this causes inflammation that allows acid to overwhelm mucus layer causing tissue damage
Bronchitis
inflammation of the bronchial tubes, walls swell and get clogged with inflammatory fluid (thick mucus builds up)
acute clears within days while chronic can last up to 2 years
asthma
chronic long term inflammation of bronchi causing the wall to fill with mucus
bronchiospasm: smooth muscle that controls the bronchi contracts cutting off air supply
emphysema
walls of alveoli weaken and rupture, creates one large surface area decreases surface area and slowing diffusion
cholestasis
ant condition that leads to bile ducts in liver clogging or being unable to perform their function
bile is needed for digestion, absorbing fats and cholesterol, and moving old RBCs
gallstones
hardened deposits in the gall bladder that block the bile duct
primary biliary cholangitis
long term disease damages bile ducts directly
cirrhosis
late stage fibrosis, liver tissue is so scarred that it impeded normal function
how does cirrosis afffect blood flow?
Increased pressure in hepatic portal veins- portal hypertension
causes fluid leakage in the legs (edema) and abdomen (ascites)
how does cirrhosis effect toxin removal?
cirrhosis prevents liver from removing bilirubin causing Jaundice
liver also removes toxins from the blood and if impaired can cause hepatic encephalopathy (build up in brain)
nitrogen narcosis
high levels of nitrogen, more nitrogen is added to the blood as the scuba diver descends
how to mammals deal with diving?
bradycardia (heart rate drop) to reduce flow to lungs
microcirculation direct blood to necessary organs only
