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Animal Physiology Pt. 2 (Circulation and Gas Exchange (Ch.42) (Circulatory…
Animal Physiology Pt. 2
Circulation and Gas Exchange (Ch.42)
Circulatory System
Function: Internal distribution of materials
Types: Closed and open
Open circulatory system: the hemoplymph, is also interstitial fluid that bathes the cells. Exs.: Arthropods and some mollusks.
Contraction of heart the hemolymph through the circulatory vessels into interconnected sinuses, spaces surrounding the organs.
Relaxation of the heart draws hemolymph back in through pores, which have valves that close when the heart contracts.
Closed circulatory system: blood is confined to vessels and is distinct from the interstitial fluid. Exs: Annelids, cephlapods, and all vertebrates.
One or more hearts pump blood into large vessels that then branch into smaller ones that infiltrate the tissues and organs.
Single vs double circulation.
Single Circulation: blood travels through the body and returns to its starting point in a single circuit.
Exs: sharks, bony fishes, and rays
Double Circulation: two circuits of blood flow.
Exs: Mammals, reptiles, and amphibians.
Fish hearts are single circuited and are basically a backwards "G." They have an artery, an atrium, a ventricle, and a vein with gill capillaries and body capillaries all connecting to one heart.
Frog hearts are double circuited. They contain atrium (r & l), ventricle, systemic capillaries, lung and skin capillaries, systemic circuit, and pulmocutaneous circuit. The single chamber does all the work.
Mammal hearts are double circuited. They contain two chambers (l & r), atrium (l & r), ventricle (l & r), systematic circuit, pulmonary circuit, lung capillaries, and systematic capillaries. Work is done in both chambers.
Important definitions
Arteries:
carry blood from the heart to the organs throughout the body
Arterioles:
arteries branch into these and they carry blood to the capillaries.
Veins:
the vessels that carry blood back to the heart.
Venules:
capillaries converge into these and then the venules converge into veins.
Capillaries:
microscopic vessels with very thin porous walls
Capillary Beds
(clusters of capillaries): infiltrate tissues passing within a few cell diameters of every cell in the body.
Blood Pressure
Moves from high to low pressure like all fluid. Contractions of heart ventricle generates it. Exerts force in all direction.
The recoil of the artery walls plays a critical role in maintaining BP and blood flow throughout the cardiac cycle.
Systolic vs Diastolic
Systolic:
when arterial BP is highest when the heart contracts during ventricular systole.
Diastolic:
diastole walls snap back. This creates low but sustainable BP when ventricles relaxed.
Lymph Circulation
Lymphatic System:
lost fluids and proteins within fluid are recovered and returned to the blood via this system.
Lymph:
recovered fluid
Lymph Nodes:
small lymph filtering organs
Blood:
connective tissue consisting of cells suspended in plasma
Plasma:
liquid matrix
Proteins and ions that help with osmosis regulation, transport, and defense.
Figure 42.16
Blood Clotting:
happens when blood vessels broken by an injury like a cut or scrape.
Response is coagulation which is the conservation of liquid components.
Function: defense, transport, and regulation.
Normal BP for humans is more than 120sys/80dia and less than 140sys/90dia
Respiratory organ function: gas exchange in any animal
Specialized structures
Gills
On the outside of body surface. Ventilation: movement of respiratory medium over surface (respiratory).
Skin
Pores on the outside of the skin that need oxygen and water. An amphibian is a good example.
Lungs
Subdivided into numerous pockets. Bridged by circulatory sys. because they do not directly make contact with other parts of body.
Breathing
Diaphragm:
a sheet of skeleton that forms the bottom wall of cavity. Pulls the ribs up and the sternum out to open the lungs
Like a syringe.
Positive vs negative pressure breathing
Positive:
inflating the lungs with forced air flow. Typically used in amphibians.
Negative:
pulling rather than pushing air into lungs. Mammals use this.
Osmoregulation and Excretion (Ch. 44)
Osmosis
Osmosis is the movement of water across a semipermeable membrane from the hypotonic to hypertonic side.
How it works: water enters and leaves a cell via osmosis. The body is constantly trying to obtain homeostasis. So water moves constantly.
Osmolarity:
the number of moles of solute per litter of solution. Human blood is about 300 milliosmoles per liter. Seawater is about 1,000 mOsm/L.
Osmoconformer:
go with the flow and be isoosmotic.
Osmoregulator:
make the rules and regulate what's going on. Control freak!
Marine animals vs freshwater animals
Marine
Osmoconformers. Osmolarity is the same as the water it swims in.
Actively transport specific solutes that establish levels in hemolymph.
Two osmoregulation strategies evolved.
One is found in bony fish, rays, and lobe fish (marine).
The other is found in sharks and other cartilage fish (marine).
Fresh
Osmoreregulator. This is because they cannot tolerate salt concentration at all. They pee constantly because they cannot hold onto much water or they will die.
Ammonia, urea, and uric acid wastes.
Ammonia is a waste produced by fish and other aquatic animals.
Ammonia is NH_4 and comes from NH_3
Urea is a waste produced by land animals like reptiles, and mammals.
Urea is nitrogenous waste that takes more energy to produce.
Uric Acid is produced by birds.
It is not very acidic and comes out as a white paste.
Excretory system
Organs involved: Kidney, ureter, urinary bladder, and urethra.
Kidney function: produce urine
Ureter function: drain the urine.
Urinary bladder function: expel the liquid.
Urethra: the tube that actually gets rid of the urine.
Nephron
Has glomerulus, Bowman's capsule, proximal tubule, loop of Henle, distal tubule, collecting duct, peritubular capillaries, and vasa recta.
Glomerulus:
single long tubule; retains blood cells and large molecules (plasma proteins), but permeable to water and small molecules.
Bowman's capsule:
^^^; blind end of the tubule that forms a cup-shaped swelling.
Proximal Tubule:
reabsorption.
Descending limb of the loop of Henle:
filtration
Ascending limp of the loop of Henle:
filtration
Distal Tubule:
regulation of Potassium and Salt during process of filtration .
Collecting duct:
processes the filtrate into urine and carries it to renal pelvis.
Peritubular capillaries:
surround the proximal tubule and distal tubules.
Vasa recta:
hairpin-shaped capillaries that serve the renal medulla. Includes the long loop of the loop of Henle.