Homework 8 Flashcards
Describe the path of blood flow from the vena cava to the aorta in a mammalian heart:
4-chambered heart
2 separate atria and 2 separate ventricles
1. O2-depleted blood returning from systemic tissues enters right heart via great veins
2. Pumped by right ventricle to the lungs
3. In the lungs O2 is taken up and CO2 released
4. Blood oxygenated in the lungs travels to the left heart
5. And pumped via the left ventricle to the systemic aorta
6. which divides and supplies all systemic tissues
Describe the path of blood flow from the vena cava to the aorta in a fish heart
2 chambered heart 1 atrium and 1 ventricle Gills Dump CO2 Pick up O2
Describe the path of blood flow from the vena cava to the aorta in an amphibian heart
3 chambered heart
2 atria, 1 ventricle
Ventricle pumps blood to forked artery
What are the advantages of a 4-chambered heart (found in mammals and birds) vs. the 2- and 3-chambered hearts found in fish and amphibians, respectively.
High pressure
Complete separation of blood (oxygenated and deoxygenated)—don’t worry about mixing of blood and systemic tissues getting deoxygenated blood
Better aerobic capacity—need it for high metabolic demand
How does the circulatory system of a grasshopper differ from that of an earthworm? How do active organisms such as grasshoppers manage to supply enough oxygen to fly?
The circulatory system of a grasshopper is open, while that of an earthworm is closed.
Openarteries open into sinuses—big cavities that surround tissues, tissues bathed in hemolymph
Heart is pumping blood that is pumping into tubes to a big swimming pool
Heat relaxes and the blood comes back in
Ostia: openings back into heart
NOT VERY EFFICIENT
Closed blood flows in a very controlled away, VERY EFFICIENT
-Grasshoppers manage to supply enough oxygen to fly through spiracles, trachael system—compensatory, highly effiicient mechanism for delivering O2 to cells
What is the cardiac cycle? Explain the steps 1-4 in Figure 49.9 (pg 1027).
The atria contract
- “Lub”: the ventricles contract, the atrioventricular (AV) valves close, and pressure in the ventricles builds up until the aortic and pulmonary valves open.
- Blood is pumped out of ventricles and into the aorta and pulmonary artery
- “Dup”: the ventricles relax, the pressure in the ventricles falls at the end of systole, and since pressure is now greater in the aorta and pulmonary artery, the aortic and pulmonary valves slam shut.
- The ventricles fill with blood.
Why does the blood pressure NOT fall to zero between heartbeats, when the heart is not actively contracting?
Blood pressure is the force that is put against your blood vessel walls. Even if your heart stops, you still have blood in your veins. You therefore have at least some blood pressure, because your blood pushes against the vessel walls. If your vessels are stretchy, you will have a low diastolic blood pressure, because the vessels are If you have ateriosclerosis, your vessels are like the small water balloon, not expanding to accommodate blood. Therefore, their diastolic BP is higher.
Explain how the interstitial fluid is able to be perfused by plasma and yet still have blood return in veins. (Perfusion is the flow of a fluid through a tissue). That is, explain 49.15 (p 1032).
Plasma fluid, minus proteins, is filtered out of capillaries, forming interstitial fluid that bathes tissues. Much of this fluid is returned to the capillaries by osmosis due to the higher protein concentration in plasma. Excess interstitial fluid drains into open-ended lymphatic capillaries, which ultimately return the fluid to the cardiovascular system.
Compare and contrast the excretory organs (kinds and mechanisms of operation) of the following animal: flatworms
Flatworms have a branching system of tubules, bulblike flame cells, and excretory pores that make up the protonephridia of flatworms. Cilia inside the flame cells draw in fluids from the body by their beating action. Substances are then expelled through pores that open to the outside of the body.
Compare and contrast the excretory organs (kinds and mechanisms of operation) of the following animal: earthworms
Earthworms have nephridia. These consist of tubules that receive a filtrate of coelomic fluid, which enters the funnel-like nephrostomes. Salt can be reabsorbed from these tubules, and the fluid that remains, urine, is released from pores into the external environment.
Compare and contrast the excretory organs (kinds and mechanisms of operation) of the following animal: insects
insects have Malpighian tubules which are extensions of the digestive tract that collect water and wastes from the body’s circulatory system.
Compare and contrast the excretory organs (kinds and mechanisms of operation) of the following animal: fish
Fish have evolved to form kidneys that can filter out all of the excess salt water. They reabsorb ions across the nephron tubules, from the glomerular filtrate back into the blood. They also actively transport ions across their gill surfaces from the surrounding water into the blood.
Compare and contrast the excretory organs (kinds and mechanisms of operation) of the following animal: humans
the kidney receives blood from a renal artery and from this blood, urine is produced. Urine drains form each kidney through a ureter, which carries the urine to a urinary bladder. From the bladder, urine is passed out of the body through the urethra.
For each of the following organisms, i) state the major osmoregulatory challenge the organism faces while living in its natural environment. (i.e. what is the major problem the organism faces related to water and salt balance?), and ii) indicate how the animal meets the challenge specified.
Paramecium
these organisms maintain a salty internal body but live in fresh water.. To prevent lysing they have use a contractile vacuole that expels water. They also have a pump that increases salts against the concentration gradient, thus creating a lower water potential inside than in the environment.
For each of the following organisms, i) state the major osmoregulatory challenge the organism faces while living in its natural environment. (i.e. what is the major problem the organism faces related to water and salt balance?), and ii) indicate how the animal meets the challenge specified.
fresh water fish like a trout
Freshwater fish have the problem of gaining too much water and losing too much salt. To fix this, they actively uptake salt through the gills and excrete large amounts of water and small amounts of salt in urine.
For each of the following organisms, i) state the major osmoregulatory challenge the organism faces while living in its natural environment. (i.e. what is the major problem the organism faces related to water and salt balance?), and ii) indicate how the animal meets the challenge specified.
marine fish like a tuna
Marine fish have the problem of gaining too much salt and losing too much water. To fix this they have glands from gills that excrete salt chloride cells in the gills and a kidney that excretes salt, but doesn’t make much urine.
For each of the following organisms, i) state the major osmoregulatory challenge the organism faces while living in its natural environment. (i.e. what is the major problem the organism faces related to water and salt balance?), and ii) indicate how the animal meets the challenge specified.
sea bird
Sea birds main problem is that they go long amounts of time without having access to freshwater so they are forced to drink salt water. They have developed salt glands that allow them to drink the salt water. These glands filter out high saline water through a nasal gland linked to the nostrils of the beak.
For each of the following organisms, i) state the major osmoregulatory challenge the organism faces while living in its natural environment. (i.e. what is the major problem the organism faces related to water and salt balance?), and ii) indicate how the animal meets the challenge specified.
kangaroo rat
The kangaroo rats thrive on some of the driest places in North America’s desserts. They can live in humidity as low as 20%, living without drinking water, only on air-dried seeds. They use metabolic water and small amount of preformed water in seeds to survive.
For each of the following organisms, i) state the major osmoregulatory challenge the organism faces while living in its natural environment. (i.e. what is the major problem the organism faces related to water and salt balance?), and ii) indicate how the animal meets the challenge specified.
shark
Sharks maintain urea in blood to keep isoosmotic so osmoregulation is not a problem. Urea, however, is very toxic and denatures proteins. To meet this challenge sharks produce TMAO to neutralize the urea and still maintain salty blood.
What are the three main functions of the kidney?
- Filtration: Fluid in the blood is filtered out of the glomerulus into the tubule system
- Reabsorption: Selective movement of solutes out of the filtrate back into the blood via peritubular capillaries
- Secretion: Movement of substances from the blood into the extracellular fluid, then into the filtrate in the tubular system
- Briefly (IN YOUR OWN WORDS) explain how a mammalian kidney is able to concentrate urine, thereby minimizing water loss. (HINT: review pgs. 1048-1049)
The loop of Henle creates a gradient of increasing osmolarity from the cortex to the medulla. This allows water to be reabsorbed in the collecting duct. The descending and ascending portion of the loop of Henle differ structurally and in their permeability to ions and water. This produces a gradient of increasing osmolarity. It also creates a countercurrent system, increasing the osmolarity of interstitial fluid.
