Circulation and gas exchange ch.42, osmoregulation and excretion ch.44
Circulation and Gas exchange ch.42
circulatory system
three basic components: circulatory fluid, set of interconnecting vessels, the heart
types of hearts
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open circulatory system, a fluid called hemolymph bathes the cells, heart contractions pump hemolymph into to the circulatory vessels to interconnected sinuses, spaces surrounding the organs
closed circulatory system, has a fluid called blood that are confined to vessels.
arteries carry blood to the organs from the heart, arteries branch out into arterioles (carry blood away from the heart to the capillaries)
capillaries, microscopic vessels with thin porous walls, capillaries also have capillary beds that infiltrate tissues. across the walls of capillaries, chemical including dissolved gases exchanged by diffusion
venules are converged from capillaries, and venules converge into veins that carry blood back to the heart (return blood toward the heart from the capillaries)
blood pressure
Systolic pressure, arterial blood pressure is highest when heart contracts during ventricular systole. when the blood pressure spikes by ventricular contractions that stretches the arteries
diastolic pressure when the elastic walls of the arteries snap back causing lower blood pressure when ventricles relax
vasoconstriction when the arterioles contract they narrow
vasodilation, the smooth muscles relax and the arterioles face vasodilation causing a diameter increase thus causing blood pressure in the arteries to fall
Osmoregulation and Excretion ch.44
osmosis the control of solute concentrations and the balance of water is either gained or lost
rids the body of nitrogenous metabolites and other metabolic waste products.
freshwater animals, conserve solutes and absorb salts from the surroundings
body fluids have to be hyperosmotic b/c they cant handle low salt concentrations
b/c they face a problem by gaining water by osmosis and the loss of salt by diffusion. this occurs b/c their internal fluids have an osmolarity higher than that of their surroundings
drinking no water but excreting large amounts of dilute urine helps them maintain water balance, and the salts that were lost and in the urine are replenished by eating.
marine animals are osmoconformers, they don't have to face challenges with water balance b/c their osmolarity is the same as the water
most aquatic animals excretes ammonia b/c they have access to a lot of water, b/c ammonia can tolerate very low concentrations
most terrestrial animals excrete urea b/c they don't live or have a lot of access to water. urea is highly concentrated urine, it combines ammonia with carbon dioxide in the liver, which makes urea binds to nitrogen to be excreted in urine
uric acid is excreted by insects, lands snails, reptiles, and birds. b/c urea is nontoxic and doesn't readily dissolve in water, thus it can be excreted without water loss
excretory organs
kidneys, transport and storing urine. the urine produced exits through the ureters that drain into the urinary bladder, when urinating the urine is expelled from the bladder through a tube called the urethra,that empties out the urine
nephrons
functions the kidneys
85% out of one million nephron reside in the cortical nephrons. reach shortly into the medulla.
juxtamedullary nephrons extend deep into the medulla, they are the production of urine that is hyperosmotic to body fluids
glomerulus long tubule or a ball of capillaries
the proximal the reabsorption to take back what needs to be kept after being dumped into the tube, keeping it, goes back into the blood
loop of henle secretion, proteins and molcuelss in the blood that didn't get filtered and try to get rid of that stuff and secrete that stuff into the tube from the blood
cup shaped the bowman's filtration everything in blood gets dumped into the capsule to go down the tube, everything goes in the capsule but blood cell and protein
distal tubule, elimination or excretion to get it out of the body
fishes balance their water loss by drinking seawater and then it gets eliminated through their gills and kidneys
sometimes to solve the problem of water balance they don't drink water in order to excrete dilute urine, the salts that were lost during diffusion get refilled when the animals eat
diffusion of water across the membrane from hypoosmotic to hyperosmotic
two ways to keep water balance, osmoconformers, isoomotic to it surroundings or osmoregulator to keep internal osmolality independent of the external environment
osmoconformers don't have to loss or gain water b/c they live in stable water that's why they are able to keep their internal osmolarity
osmoregulation allows animals to live in environments that are inhabitable to osmoconformers (terrestrial, freshwater)
ventricle contraction generate blood pressure
one or more hearts pump the blood into the large vessels that branch off into the smaller one to infiltrate organs
closed circularity systems include all of the vertebrates (annelids, squids, and octopus)
relaxing of the heart bring back the hemolymph to the pores which are equipped with vales closing when the heart contracts. the hemolymph get circulated when the sinuses get squeezed by the bodies movements. (large crustaceans, lobsters and crabs)
single circulation, the blood goes through the heart once in each complete circuit through the body
single circulation the blood that leaves the heart has to pass through the two capillary beds before it returns to the heart
double circulation the pumps are combined into two circuits called the heart. the two pumps simplifies the circulation cycle
the right side of the heart delivers the oxygen poor blood to the capillaries of the gas exchange tissues, where net movement of oxygen in the blood and carbon dioxide out of the blood, which is the pulmonary circuit if capillary beds are involved in the lungs, but if it is pulmocutaneous circuit the capillaries are included in the lungs and skin
this circulation provides blood to the brain, the muscles, and other organs b/c the heart repressurizes blood that is destined tot eh tissues after passing through capillary beds of the lungs and or the skin.
gills have a total surface area greater than that of the body's exterior
frogs and amphibians have three chamber hearts, including two atria and one ventricle. a ridge within the ventricles that diverts 90% of the oxygen-rich blood from the left atrium to the systemic circuit.
in alligators, caimans, and crocodilians. have a complete septum and the pulmonary and systemic circuits that connect where the arteries exit the heat allowing the arterial valves to shunt the blood away from the lungs when they are submerged underwater
and the oxygen-poor blood from the right atrium goes into the pulmocutaneous circuit
the frog b/c of its incomplete division of the ventricles the frog can adjust circulation, that allows it to shut the blood flow off temporarily to the ineffective lungs, as blood continues to flow to the skin which acts as a site of gas exchange while the frog is underwater
turtles, snakes, and lizards have a three chambered heart, and an incomplete septum dividing the ventricle into left and right chambers
the aortas lead into the systemic circulation
mammals have two atria and two completely divided ventricles, the left side receives and pumps oxygen-rich blood, while the right side receives and pumps oxygen poor blood
they cant vary blood from the lungs unless it varies throughout the body
ventilation maintains the partial pressure gradients for the oxygen and carbon dioxide, across the gills for the gas exchange
to further the ventilation the gills help either by letting water move over the gills or though the water
for example octopuses and squids ventilate their gills when they eject and take in the water
lungs
a localized respiratory organs, b/c the respiratory surface of the lungs they do not come in direct contact with the rest of the body, the gap must be bridged by the circulatory system that then can transport gases from the lungs to the body
breathing the inhalation and exhalation of air
positive pressure breathing, air is forced into the lungs
negative pressure breathing, the pulling of air into the lungs
diaphragm, skeletal muscle that form the bottom wall of the cavity. contracting expands the ribs, the front wall by pulling the ribs upward and the sternum goes outward, thus the diaphragm contracts that expands the thoracic cavity downward
blood supplies air to the cells and the tissues
plasma are blood electrolytes, the dissolved ions are essential for the blood, and some ion buffers the blood and help maintain osmotic balance
red blood cells transportation of oxygen and white blood cells that function in defense
erythrocytes, human blood contains 5-6million red cells, disk shape that allows rate of diffusion of oxygen across the plasma membrane
leukocytes, some are phagocytic that engulf and digesting microorganisms like debris from the body own dead cells
other leukocytes, called lymphocytes that develop into b-cell and t-cells that mount the immune response against foreign substances
lost fluids and proteins return the to blood via the lymphatic system
entering the lymphatic system by diffusion, and the capillaries that lost blood is called lymph, the lymphatic system drains into the large veins into the cardiovascular system at the base of the neck.
b/c the systems join enables the lipids to transfer from the small intestine to the blood
lymph vessels have the valves that stop the blood from backflow. the vessels produce rhythmic contractions, that draw fluid into the small lymphatic vessels.
the lymph vessels, their are lymph filtering organs called lymph nodes, that defend the body. Inside each one their is connective tissue that filled with white blood cells that function in defense.
osmolarity, measure of concentration moles/liter
neurons in the medulla oblongata, the neural circuits in the medulla form a pair of breathing control centers that helps the breathing rhythm
breathing deeply expands the lungs, but negative feedback stop them from overexpnading
inhalation their are sensor that detect the stretching of the lungs tissue sending nerve impulses that control the circuits of the medulla that prevent further inhalation
isosmotic, two solutions with the same osmolarity
permeable membrane separates the solution, where the eater molecules will continue to cross the membrane at equal rates in both directions, and no net movement of water by osmosis between isoosmotic solutions
if the solutions differ in osmolarity, the higher solution the solutes are hyperosmotic, the more dilute the solution it will be hypoosmotic , water flows from a hypossmotic solution to a hyperosmotic one
for example sharks need to have a lower salt concentration then the water in its surroundings, which is why salt diffuses through their gills
filtration. filtrate the salts, sugars, amino acids, the nitrogenous waste, cross the membrane
reabsorption, recovers useful molecules and water that filtrate that returns them to the body
secretion, the nonessential solutes and waste are left in the filtrate or are added to it.
metanephridia, earthworms excretory organs collect fluid directly from the coelom, their waste is excreted into the environment
malpighian tubules insects and terrestrial arthropods, remove nitrogenous waste and function in osmoregulation
protonephridia, flatwoms form a network of dead end tubules.
the tubules extend from dead end tips immersed in hemolymph to openings of the digestive tract
when the urine moves along the tubules, the transport epithelium that border the lumen reabsorbing the solutes and returns them to the blood in the capillaries
the tubules are connected to the external openings that branch though out the flatworm body, that has no coelom. During the filtration the beating cilia draws the water out of the solutes from the interstitial fluid through the flame bulb that releases filtrate into the tubule networks
the filtrate lets them excrete their urine in their environment
frogs for example breath through there skin