Chapter 42 Questions

Front 1

Compare the bioenergetics of animals when energy balance is negative

Back 1

When blood glucose level drops below set point the pancreas secrets the hermone glucagon into the blood. Glucagon promotes the breakdown of glycogen into the liver and the release of glucose into the blood, increasing blood glubose level.

Front 2

Compare the bioenergetics of animals when energy balance is positive

Back 2

Blood glucose level rises after eating. The pancreas secretes the hormone insulin into the blood. Insulin enhances the transport of gluvose into body cells and stimulate the liver and muscle cells to store gluvose as glycogen. as a result, blood glucose level drops. (90mg glucose/100mL blood)

Front 3

Explain how a gastrovascular cavity functions in part as a circulatory system

Back 3

Gastrovascular cavities in small animals with simple body plans mediate exchange between the environment and cells that can be reached by short-range diffusion.

Front 4

Distinguish between open and closed circulatory systems.

Back 4

In an open circulatory system, fluid called hemolymph bathes the tissues and organs directly. closed systems circulate fluid in a closed network of pumps and vessels.

Front 5

List three basic components common to both circulatory systems.

Back 5

A circulatory fluid, a set of interconnecting tubes, and a muscular pump(the heart)

Front 6

List the structural components of a vertrabrate circulatory system and relate their structure to their functions

Back 6

In vertebrates, blood flows in a closed circulatory cardiovascular system consisting of blood vessels and a two- to four-chambered heart. Arteries convey blood to capillaries, the sites of chemical exchange between blood and interstitial fluid. Veins return blood from capillaries to the heart.

Front 7

Compare and contrast the circulatory system of fish, amphibions, non-bird reptiles, and mammals or birds.

Back 7

Fishes,rays, and sharks have a single pump in their circulation. Air-breathing vertebrates have two pumps combined in a single heart.

Front 8

Distinguish between pulmonary and systemic cicruits and explain the functions of each.

Back 8

Pulmonary circuit is the pump on the right side of the heart that delivers oxygen-poor blood to the capillary beds of the gas exchange tissue, where there is a movement of )2 into the blood and of Co2 out if the blood.
After the oxygen rich blood leaves the gas exchange tissue, it enters the other pump, the left side of the heart, contractions of the heart propels this capillary beds in organs and tissues throughout the body. Following the exchange of O2 and CO2, as well as nutrients and waste products, the now oxygen-poor blood returns to the heart completing the systemic circuit

Front 9

Explain the advantage of double circulation over a single circuit

Back 9

In a double circulation the heart repressurizes the blood keeping high pressure and in a single circuit they need to move to keep pressure up.

Front 10

Define a cardiac cycle, distingusih between systole and diastole, and explain what causes the first and second heat sounds.

Back 10

A cardiac cycle is the alternating contractions and relaxations of the heart. The contraction phase is called systole. The relaxation phase is called the diastole.
The first heart sound is created by the recoil of blood against the closed AV valves. The second sound is produced by the recoil of blood against the closed semilunar valves.

Front 11

Define cardiac output and describe two factors that influence it.

Back 11

cardiac output is the volume of blood pumped per minute by the left ventricle of the heart. One factor is the rate of contraction(heart rate) the second factor is stroke volume, the amount of blood pumped by a ventricle in a single contraction

Front 12

List the four heart valves, describe their location, and explain their functions.

Back 12

An antrioventricular (AV) valve lies between the atrium and ventricle keeping blood from flowing back into the atria. Semilunar vales are located at the two exits of the heart where the aorta leaves the left ventricle and where the pulmonary artery leaves the right ventricle; to prevent significant backflow.

Front 13

Define heart murmer and explain its cause.

Back 13

Heart murmer is when blood squirts backward through a defective valve.

Front 14

Define sinoatrial (SA) node and describe its location in the heart.

Back 14

SA is a region of the heart composed of specialized muscle tissue that sets the rate and timing at which all cardiac muscle cells contract.Located in the wall of the right atrium

Front 15

Describe the orgin and pathway of the action potential (cardiac impules) in the normal human heart.

Back 15

Pacemaker generates waves of signals to contract(SA node)

Signals are delayed at AV node.

Signals pass to heart apex(bundle branches)

Signals spread throughout ventricles(purkinje fibers)

Front 16

Relate the structure of capillaries, arteries, and veins to their function.

Back 16

Capillaries are very small & thin blood vessels to faciliate the exchange of substances between the blood in capillaries and the interstitial fluid.

Veins and arteries have more complex organization. Two layers of tissue surround the endothelium allowing the vessel to stretch and recoil.

Arteries are 3 times as thick to accomodating blood pumped at high pressure

Front 17

Explain why the blood flow through capillaries is substantially slower than it is through arteries and veins

Back 17

The number of capillaries is enormous that the total cross-section area is much greater in capillary beds than in arteries or veins

Front 18

Define blood pressure and describe how it is measured

Back 18

Blood pressure is the hydrostatic force that blood exerts against the wall of a vessel. Blood pressure is recorded as two numbers separated by a slash. The first number is the systolic pressure; the second is the diastolic pressure

Front 19

Explain how blood returns to the heart even though it must sometimes travel from the lower extremities against gravity.

Back 19

Rythimic contractions of smooth musle in the walls of venules and veins aid in the movement of blood. Second, the contraction of skeletal muscles during excercise squeezes blood through veins

Front 20

Explain how blood flow through capillarys beds are regulated.

Back 20

Nerve impulses and hormones traveling throughout the bloodstream, and chemicals produced locally

Front 21

Explain how osmotic pressure and hydrostatic pressure regulate the exchange of fluid and solutes across capillaries

Back 21

In places where blood is greater then the osmotic pressure difference, there is a net loss of fluid from the capillaries.
The lymphatic system returns fluid to the blood and parallels the circulatory system in it extent and its mechanisms for fluid flow under low hydrosatic pressure

Front 22

Describe the composition of lymph and explain how the lymphatic system helps the normal functioning of the circulatory system

Back 22

The lymph is the fluid lost through capillarys. Its composition is about the same as that of interstitial fluid. The lymphatic systim drains into large veins of the cirulatory system at the base of the neck. This joining fuctions in the transfer of lipids from the small intestine to the blood.

Front 23

Explain the role of lymph nodes in body defense

Back 23

When a body is fighting an infection,housing cells that attack viruses and bacteria multiply rapidly.

Front 24

Decribe the composition and functions of plasma.

Back 24

Dissolved in the plasma are ion and proteins that, together with the blood cells, function in osmotic regulation, transport,and defense.

Front 25

Relate the structure of erythrocytes to their function

Back 25

Erythrocytes are small disks that are biconcave-thinner in the center then the edges. This shape increases surfacearea, enhancing the rate of diffusion of O2 across their plasma membrane

Front 26

Describe the hormonal control of erythrocyte production

Back 26

a negative-feedback mechanism, sensitive to the amount of O2 reaching the bodys tissues via blood, controls erythrocyte production. If tissues do not recieve enough O2, the kidneys synthesize and secrete a hormone called erythropeietin

Front 27

Outline the sequence of events that occurs during blood clotting and explain what prevents spontaneous clotting in the absence of injury

Back 27

Connective tissue in vessel wall is exposed making nerby platelets stick. the platlets fomr a plug to prevent blood loss. The seal is reinforced by a clot of fibrin. Anticlotting factors prevent spontaneous clottin the the absence of injury.

Front 28

Distinguish between a heart attack and a stroke

Back 28

Heart attack is the death of cardiac muscle tissue resulting from prolonged blockage of one or more coronary arteries.
A stoke is Tte death of nervous tissue in the brain, usually resulting from rupture or blockage of arteries in the head.

Front 29

Describe the general requirments for a respiratory surface and list a variety of repiratory organs that meet these requirments.

Back 29

Respiratory surfaces are always moist and long and thing. The skin serves as a respiratory organ in some animals, including earthworms and some amphibians. A dense network of capillaries faciliates the exchange of gases between the circulatory system and the environment. The general body of most animals is a respiratory organ that is extensively folded or branched.

Front 30

Describe the countercurrent exchange and explain why it is more efficient than the concurrent flow of water and blood.

Back 30

Countercurrent exchange is the exchange of a substance or heat between two fluids flowing in opposite directions.Because blood flows in the opposite direction to that of water passing over gills, at each point in its ravel blood is less saturated with O2

Front 31

For human respiratory system, describe the movement of air through air passageways to the alveolus, listing the structures that air musst pass through on its journey

Back 31

From the nasal cavity and pharynx, inhaled air passes through the larynx, trachea, and bronchi to the bronchioles, which end in microscopic alveoli lined by oxygen-poor blood to the alveoli; branches of the pulmonary veins transport oxygen-rich blood from the alveoli back to the heart.

Front 32

Compare positive and negative pressure breathing. Explain how respiratory movements in humans ventilate the lungs.

Back 32

Positive pressure breathing inflates the lungs with forced airflow and negative pressure breathing pulls air into their lungs. Humans breathe by changin the pressure withing their lungs by contracting the diaphragm

Front 33

Explain how the respitory systems of birds and mammals differ.

Back 33

Mammals ventilate their lungs by negative pressure breathing pulling air into their lungs. Birds have eight or nine sacs that act as bellows, keeping air flowing through the lungs in only one direction. Every exhalation completly renews the air in the lungs

Front 34

Explain how breathing is controlled in humans

Back 34

Control centers in the medulla oblongata and pons of the brain regulate the rate and depth of breathing. Sensors detect the pH of cerebrospinal fluid, and the medulla adjusts breathing rate and depth to match metabolic demands. Secondary control over breathing is exerted by sensors in the aorta and caraotid arteries that monitor blood levels of O2 and CO2 and blood pH

Front 35

Define partial pressure and explain how it influences diffusion across respiratory surfaces

Back 35

Partial pressure is the pressure exerted by a particular gas in a mixture of gases. Gases diffuse from where their partiel pressures are higher to where they are lower

Front 36

Describe how carbon dioxide is picked up at the tissues and deposited in the lungs

Back 36

CO2 from respiring cells diffues into the blood plasma and then into erythrocytes. There the CO2 reacts with water and froms H2CO3, which dissociates into H+ and HCO3-. Most of the H+ bind to hemoglobin and other proteins, minimizing the change in blood pH. The HCO3- diffuses into the plasma. When blood flows through the lungs, the relative partial pressure of CO2 favor the diffusion of CO2 out of the blood. As CO2 diffuses into alveoli, the amount of CO2 diffuses iinto alveoli, the amount of CO2 in the blood decreases. This decrease shifts the chemical equilibrium in favor of the conversion of HCO3- to CO2, eneabling further net diffusion of CO2 into alveoli

Front 37

Describe respiratory adaptations of diving mammals and the roll of myoglobin

Back 37

One adaption is the ability to store large amounts of O2. They have a high concentration of an oxygen-storing protein called myoglobin in their muscle. They are able to conserve O2 by using minimal muscle effort to glide up or down by changing their buoyancy

Front 38

Define osmolarity and distinguish among isoosmotic, hyperosmotic, and hypoosmotic solutions.

Back 38

Osmolarity is solute concentration expressed as molarity.
If two solutions are separated by a selectively permeable membrane have the same osmolarity, they are said to be isoosmotic

When two solutions differ in osmolarity, the one with the greater concentration of solutes is said to be hyperosmotic and the more dilute solution is said to be hyposmotic

Front 39

Distinguish between osmoregulators and osmoconformers. Explain why osmoregulation has an energy cost.

Back 39

Osmoconformer is isoosmotic with its surroundings and osmoregulator controls its internal osmolarity independent of that of its environment. Osmoregulation has an energy cost because they need to control the water uptake and loss in a hypoosmotic or hyperosmotic environment.

Front 40

Distinguish between stenohaline and euryhaline animals, and explain why euryhaline animals include both osmoconformers and osmoregulators.

Back 40

Stenohaline cannot tolerate substantial changes in external osmolarity while euryhaline animals can survive large fluctuations in external osmolarity. Certain fish go change depending on their environment like the salmon

Front 41

Discuss the osmoregulatory strategies of marine animals

Back 41

Some fishes such as cod drink large amounts of sea water and use both their gills and kidneys to rid themselves of salt. Sharks use salt, urea, TMAO, and other compunds maintained in the body fluids of the shark result in an osmolarity very close to that of sea water

Front 42

Explain how the osmoregulatory problems of freshwater animals differ from those of marine animals

Back 42

The body fluids of freshwater animals must be hyperosmotic because animal cells cannot tolerate salt concentrations as low as those of lake or river water.

Front 43

Describe anhydrobiosis as an adaptation that helps tardigrades and nematodes to survive periods of dehydration

Back 43

Nematodes and tardigrades go through anhydrobiosis when the environment is at an extreme hydration. This allows them to survive during hard times.

Front 44

Describe some adaptions that reduce water loss in terrestrial animals

Back 44

Waxy cuticle protects plants, the body covering of most terrestrial animals helps prevent dehydration. some animals are nocturnal. land animals maintain water balance by drinking and eating moist foods and by producting water metabolically through cellular respiration

Front 45

Describe the production and elimination of ammonia. Explain why ammonia excretion is most common in aquatic species.

Back 45

When nucleic acids and proteins are broken apart for energy or converted to carbohydrates or fats, enzymes remove the nitrogen in the form of ammonia. Many aquatic species have ammonia because it can easly pass through membranes and are readily lost by dissusion to the surrounding water.

Front 46

Compare strategies to eliminate waste as ammonia, urea, or uric acid. Note which animal groups are associated with each process and why a particular strategy is most adaptive for a particular group

Back 46

Aquatic animals excrete ammonia across the body surface or epithelia into the surrounding

The liver of of mammals and most adult amphibians convert ammonia to less toxic urea, which is carried to the kidneys, concentrated, and excreted with a minimal loss of water. Urea is at a very low toxicity.(mammals adult amphibians sharks some bony fish and turtle)

Uric acid is eliminated as a semisolid paste with very little water loss. This is a great advantage for animals with little access to water(snails, insects and reptiles)

Front 47

Identify and describe the function of each structure in the mammalian excretory system

Back 47

Filtration-The excretory tubule collects a filtrate from the blood. Water and solutes are forced by blood pressure across the selectively permeable membranes of a cluster of capillaries and into the excretory tubule

Reabsorption- The transport epithelium reclaims valuable substances from the filtrate and returns them to the body fluids.

Secretion- Other substances, such as toxins and acess ions, are extracted from body fluids and added to the contents of the excretory tubule.

Excretion- The altered filtrate leaves the system and the body