Bio 106 Exam

Which of the following is NOT transported by the circulatory system?

Saliva.

Is the blood in the 2-chambered heart oxygenated or deoxygenated?

Deoxygenated.

Can the blood in the right side pass directly to the left side?

No, it must leave the heart and then return to the left side.

Which gas is in higher concentration in the blood as it approaches the lungs?

CO2

When SA:Vol is large, what does that mean?

Lots of surface area relative to volume.

What is meant by "counter current"?

The blood and the water flow in opposite directions through the gill.

Air enters the respiratory system through the trachea. The trachea branch into smaller and smaller tubes. What is the name for the part of the lung where gas exchange happens??

Alveolus.

Which tissues will receive the most oxygen from hemoglobin? Look at all of the options before deciding.

Tissues with a low amount of oxygen and a low pH (acidic).

Which nitrogenous waste requires the greatest water loss to rid it from the body?

Ammonia.

Name the part of the system indicated by the arrow (the red part)...

The glomerulus.

Which of the following is true for Tony's urine?

Urine more dilute.

Which phylum/phyla have flame cells as part of their excretory system?

Platyhelminthes (flatworms).

Name the parts of the neuron (see diagram on slide)...

1\=dendrite 2\=cell body 3\=axon

What would happen if a potassium gate opened?

There would be net movement of K out of the cell.

What happens when some Na+ gates open?

Na+ diffuses in and inside becomes more positive.

What happens when some K+ gates open?

The charge difference between inside & outside the cell is restored.

Which ions are moving at this stage?

K+

When lidocaine is applied to the nerve, would it be able to depolarize?

No.

At resting potential, which of the ion channel gates are closed?

Na+ activation gates and the K+ gates.

During an action potential, what happens to restore the charge difference across the cell membrane?

K+ moves out of the cell.

At resting potential, which of the ion channel gates are closed?

Na+ activation gates and the K+ gates

What is the concentration gradient for Calcium in the nervous system?

Higher on the outside; lower on the inside.

What do the neurotransmitters bind to?

Receptors on the cell membrane of the receiving neuron.

Which types of chemically-sensitive gated channels on a dendrite would result in an EPSP?

Na+

Which muscle type is associated with the stomach?

Smooth muscle.

Name the parts of the sarcomere (contractile unit):

1\=Z-line 2\=Actin 3\=Myosin

This is called the "sliding filament model". What filaments are "sliding"?

Actin slides past myosin.

If calcium ions are not present in a sarcomere, muscle contraction cannot occur because...

Myosin cannot bind to actin.

Once the community reaches the climax stage, what happens next?

The climax community will continue to experience disturbances over time.

What trophic level do plants occupy?

Producers.

What trophic level do herbivores occupy?

Primary Consumers.

In this food web, what is the highest trophic level of the hawk?

Fifth-level Consumer

LEARN BEFORE LECTURES!!

If a substance takes 1 second to diffuse 100 um, how long will it take to diffuse 1 cm?

3 hours

How does a circulatory system solve this problem of diffusion time who lack a simple body plan?

Animals that lack a simple body plan display an alternative adaptation for efficient exchange: a circulatory system. By moving fluid between each cell's immediate surroundings and the rest of the body, such a system makes it possible for all exchange to occur over very short distances.

Name the three components of a circulatory system:

1. A circulatory fluid.
2. A set of interconnecting vessels.
3. A muscular pump; the heart.

What is hemolymph?

It is a circulatory fluid that acts as the interstitial fluid as well.

In what ways is a closed circulatory system different from an open one?

In an open circulatory system, the circulatory fluid, called hemolymph, is also the interstitial fluid that bathes body cells; there is no distinction between the circulating fluid and the interstitial fluid.

In a closed circulatory system, a circulatory fluid called blood is confined to vessels and is distinct from the interstitial fluid.

What is the evolutionary benefit for having an open circulatory system?

The lower hydrostatic pressures typically associated with open circulatory systems allow them to use less energy than closed systems. In some invertebrates, open circulatory systems serve additional functions. For example, spiders use the hydrostatic pressure of their open circulatory system to extend their legs.

What is the evolutionary benefit for having a closed circulatory system?

The benefits of closed circulatory systems include blood pressure high enough to enable the effective delivery of O2 and nutrients in larger and more active animals. Among the mollusks, for instance, closed circulatory systems are found in the largest and most active species, the squids and octopuses. Closed systems are also particularly well suited to regulating the distribution of blood to different organs

Distinguish between arteries, veins and capillaries of a closed system:

❖ Arteries: carry blood from the heart to organs throughout the body. Within organs, arteries branch into arterioles.
❖ Veins: the vessels that carry blood back to the heart; venules converge into veins.
❖ Capillaries: microscopic vessels with very thin, porous walls. Local networks of capillaries, called capillary beds, infiltrate tissues, passing within a few cell diameters of every cell in the body. Across the thin walls of capillaries, dissolved gases and other chemicals are exchanged by diffusion between the blood and the interstitial fluid around the tissue cells. At their "downstream" end, capillaries converge into venules.

Distinguish between the chambers of the heart:

❖ Atrium: the chambers that receive blood entering the heart.
❖ Ventricle: the chambers responsible for pumping blood out of the heart.

Fill in the blanks to follow the pathway of blood through the double circulation system of mammals:

From the right ventricle, blood travels to the lungs via the pulmonary arteries. As the blood flows through the capillary beds in the lungs it gains Oxygen (O2) gas and unloads carbon dioxide (CO2) gas which is then exhaled. From here, the blood returns to the left atrium (chamber of the heart). Next it passes into the left ventricle (chamber of the heart). From here, the blood is pumped to the systemic system which includes capillary beds in the head and arms and also capillary beds in the abdominal organs and legs (hind limbs). As the blood passes through these capillary beds it becomes oxygenated / deoxygenated (circle one). From here it returns to the right atrium then flows to right ventricle (chamber of the heart) where the circuit begins again.

For each type of blood vessel, indicate how its structure matches its function:

a. Thin walls of capillaries: Capillaries are the smallest blood vessels, having a diameter only slightly greater than that of a red blood cell. Capillaries also have very thin walls, which consist of just an endothelium and a surrounding extracellular layer called the basal lamina. The exchange of substances between the blood and interstitial fluid occurs only in capillaries because only there are the vessel walls thin enough to permit this exchange.

b. Very thick walls of arteries: Arterial walls are thick, strong, and elastic. They can thus accommodate blood pumped at high pressure by the heart, bulging outward as blood enters and recoiling when the heart relaxes between contractions. Arteries and arterioles play an essential role in regulating blood flow to the brain, muscles, reproductive organs, and elsewhere.

c. Less thick walls of veins: Because veins convey blood back to the heart at a lower pressure, they do not require thick walls. For a given blood vessel diameter, a vein has a wall only about a third as thick as that of an artery. Unlike arteries, veins contain valves, which maintain a unidirectional flow of blood despite the low blood pressure in these vessels.

What does it mean to say "the partial pressure" of a gas?

The pressure exerted by a particular gas in a mixture of gases.

Which direction does a gas diffuse -

From higher to lower.

Is it easier for animals to extract oxygen from water or air?

Air

Compared to water, air is much less dense and less viscous, so it is easier to move and to force through small passageways. As a result, breathing air is relatively easy and need not be particularly efficient. Water's lower O2 content, greater density, and greater viscosity mean that aquatic animals such as fishes and lobsters must expend considerable energy to carry out gas exchange.

Why are respiratory surfaces large and thin?

The movement of O2 and CO2 across respiratory surfaces takes place by diffusion. The rate of diffusion is proportional to the surface area across which it occurs and inversely proportional to the square of the distance through which molecules must move. In other words, gas exchange is fast when the area for diffusion is large and the path for diffusion is short. As a result, respiratory surfaces tend to be large and thin.

List some of the different respiratory surfaces used by different types of animals for gas exchange (give the surface and the animal/s that use it):

❖ The skin serves as a respiratory organ (earthworms, some amphibians, and some other animals).
❖ Gills (fish, lobsters, squid, etc.).
❖ Tracheae (insects).
❖ Lungs (reptiles, birds, and mammals).

What is countercurrent exchange?

Exchange between fluids flowing in opposite directions.

Briefly describe the structure of the tracheal system of insects:

Although the most familiar example of such an arrangement is the lung, the most common is the insect tracheal system, a network of air tubes that branch throughout the body. The largest tubes, called tracheae, open to the outside. At the tips of the finest branches, a moist epithelial lining enables gas exchange by diffusion. Because the tracheal system brings air within a very short distance of virtually everybody cell in an insect, the efficient exchange of O2 and CO2 does not require participation of the animal's open circulatory system.

Briefly describe the structure of lungs:

Lungs are localized respiratory organs. Representing an infolding of the body surface, they are typically subdivided into numerous pockets. Because the respiratory surface of a lung is not in direct contact with all other parts of the body, the gap must be bridged by the circulatory system, which transports gases between the lungs and the rest of the body. Lungs have evolved both in organisms with open circulatory systems, such as spiders and land snails, and in vertebrates.

Follow the pathway of oxygen from the mouth/nose into the deepest part of the lungs:

Air enters the pharynx and through the larynx and then into the trachea. This structure branches into two bronchi, each one leading to a lung. Within the lung, these passageways branch into very fine tubes called bronchioles. Gas exchange happens in sacs called alveoli clustered at the tips of the tiniest of these fine tubes.

How does cellular respiration create a PO2 gradient that facilitates the net movement of oxygen from the blood, into the interstitial fluid (and ultimately into the cells)?

Respiratory pigments.

Why are respiratory pigments in the blood necessary?

Respiratory pigments circulate with the blood or hemolymph and are often contained within specialized cells. The pigments greatly increase the amount of O2O2 that can be carried in the circulatory fluid.

. Name the pigment used by arthropods / molluscs:

blue pigment hemocyanin.

What is the metal?

Copper.

Name the pigment used by vertebrates / many invertebrates:

Hemoglobin

What is the metal?

Iron.

The blood then passes tissues where PO2 is 20mm Hg.

Hemoglobin delivers 65% of its O2 to the tissues.

Which two functions are functionally and physiologically linked and, thus, discussed together in this section?

❖ Osmoregulation, the general term for the processes by which animals control solute concentrations in the interstitial fluid and balance water gain and loss.
❖ Excretion, the process that rids the body of nitrogenous metabolites and other metabolic waste products.

What toxic compound does the breakdown of nitrogenous molecules create?

Ammonia.

What types of things become part of the filtrate?

Here, we will consider the role of the nephron in forming the filtrate in the mammalian kidney. We will then focus on how tubules, capillaries, and the surrounding tissue of the nephron function together in processing that filtrate.

What is the excretory system of each of the following?

a. Platyhelminthes: Many invertebrates such as flatworms use a nephridium as their excretory organ.
b. Annelids: The annelid excretory system is made up of long tubular organs called nephridia
c. Insects & other terrestrial arthropods: Malpighian tubules
d. Vertebrates: Components of this system in vertebrates include the kidneys, liver, lungs, and skin.

Which parts of the kidney are permeable to water? List them & indicate if it is passive flow or active transport:

Proximal tubule, Descending limb of the loop of Henle, collecting duct

Which parts are permeable to salt (NaCl)? List them & indicate if it is passive flow (P) or active transport (A):

Proximal tubule, epithelium actively transports NaCl into the interstitial fluid, distal tubule, collecting duct, Ascending limb of the loop of Henle

What hormone is key for managing urine concentration in the kidney?

One key hormone in the regulatory circuitry of the kidney is antidiuretic hormone (ADH), also called vasopressin.

What is the specific target tissue for its action?

Kidney tubules.

Define the following terms:

a. Synapse: a junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.
b. Neurotransmitter: a chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse or junction, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure.

What is the function of each of the following in the nervous system?

a. Sensory neurons: like those in the snail's siphon, transmit information about external stimuli, such as light, touch, or smell, or internal conditions, such as blood pressure or muscle tension.
b. Interneurons: form the local circuits connecting neurons in the brain or ganglia. Interneurons are responsible for the integration (analysis and interpretation) of sensory input.
c. Motor neurons: transmit signals to muscle cells, causing them to contract. Additional neurons that extend out of the processing centers trigger gland activity.

Identify the functions of each component of the nervous system:

a. Peripheral nervous system: the sensory and motor neurons that connect to the central nervous system.
b. Central nervous system: where signal integration occurs; in vertebrae animals, the brain and spinal cord. c. Motor neurons: transmits signals from the brain or spinal cord to muscles or glands.

Answer the following questions to describe the resting potential of a mammalian neuron:

a. Where is the highest concentration of potassium ions? Inside the cell.
b. Where is the highest concentration of sodium ions? Outside the cell
c. Where is the highest concentration of chloride ions? Outside the cell
d. Where is the highest concentration of large anions? Inside the cell

Which direction does the sodium-potassium pump sodium?

Outside the cell.

Which direction does the sodium-potassium pump potassium?

Inside the cell.

What is a "voltage-gated" ion channel?

A channel that opens or closes in response to a shift in the voltage across the plasma membrane of the neuron.

When voltage-gated potassium channels open, they allow for K+ to move down its concentration gradient across the cell membrane:

a. Which direction will it flow?
Outside the cell
b. How does this flow of ions influence the inside of the cell? A: it becomes more negative

When voltage-gated sodium channels open, they allow for Na+ to move down its concentration gradient across the cell membrane:

a. Which direction will it flow?
Inside the cell
b. How does this flow of ions influence the inside of the cell? A: it becomes more positive
c. Which term is associated with this result? depolarization

Which gates open during depolarization?

Sodium (Na)

Why does an action potential only move ahead, toward the axon terminus (rather than backwards toward the cell body)?

Do not travel back; cannot produce action potential behind it.

The strength of an action potential is always the same. How, then, do we distinguish between stronger and weaker signals such as louder vs softer sounds?

The frequency of action potentials conveys information: The rate at which action potentials are produced in a particular neuron is proportional to input signal strength. In hearing, for example, louder sounds trigger more frequent action potentials in neurons linking the ear to the brain. Differences in the number of action potentials in each time are in fact the only variable in how information is encoded and transmitted along an axon.

What are the two ways to speed up an action potential (list them)?

Wider axon and electrical insulation.

What evolutionary adaptation do fast-moving invertebrates have (be specific)?

Giant axons.

Vertebrates have nerves with a myelin sheath. What is the function of a myelin sheath?

Electrical insulation.

What is "saltatorial transmission"?

An action potential propagating along a myelinated axon appears to jump from one such node to another.

How does the myelin sheath (made of Schwann cells or oligodendrocytes) speed up action potential transmission?

Myelin can greatly increase the speed of electrical impulses in neurons because it insulates the axon and assembles voltage-gated sodium channel clusters at discrete nodes along its length. Myelin damage causes several neurological diseases, such as multiple sclerosis.

What is a "synaptic vesicle"?

Packaging it in multiple membrane-enclosed compartments

In a chemical synapse, what ion enters the axon at the terminal causing the synaptic vesicles to fuse with the terminal membrane to release the neurotransmitter?

Ca 2+

What does the neurotransmitter bind to on the post-synaptic cell?

Ligand-gated channels

What happens to create an EPSP?

At some chemical synapses, the ligand-gated ion channels are permeable to both K+ and N+. When these channels open, the membrane potential depolarizes toward a value roughly midway between EK and ENa. Because such a depolarization brings the membrane potential toward threshold, it is called an excitatory postsynaptic potential (EPSP).

What happens to create an IPSP?

At other chemical synapses, the ligand-gated ion channels are selectively permeable for only K+ or Cl-. When such channels open, the postsynaptic membrane hyperpolarizes. A hyperpolarization produced in this manner is an inhibitory postsynaptic potential (IPSP) because it moves the membrane potential further from threshold.

What sequence of events results in spatial summation?

If the summed postsynaptic potentials depolarize the membrane at the axon hillock to threshold, the result is an action potential. Summation can also involve multiple synapses on the same postsynaptic neuron. If such synapses are active at the same time, the resulting EPSPs can add together through spatial summation.

What is the name of the region where summation occurs?

Axon hillcock.

What main molecule makes the thin filament?

The major component of thin filaments is the globular protein actin. In thin filaments, two strands of polymerized actin are coiled around one another; similar actin structures called microfilaments function in cell motility.

What molecule makes the thick filament?

The thick filaments are staggered arrays of myosin molecules. Muscle contraction is the result of filament movement powered by chemical energy; muscle extension occurs only passively

When ATP runs low, which other molecules are used to continue contractions beyond ~15 minutes?

At rest, most muscle fibers contain only enough ATP for a few contractions. Powering repetitive contractions requires two other storage compounds: creatine phosphate and glycogen. Transfer of a phosphate group from creatine phosphate to ADP in an enzyme-catalyzed reaction synthesizes additional ATP. In this way, the resting supply of creatine phosphate can sustain contractions for about 15 seconds. ATP stores are also replenished when glycogen is broken down to glucose. During light or moderate muscle activity, this glucose is metabolized by aerobic respiration. This highly efficient metabolic process yields enough power to sustain contractions for nearly an hour.

In Figure 39.5, the divots in the brown actin units represent the binding sites for myosin. What prevents myosin from binding to actin in a resting muscle (as shown in 39.5a)? Mention all of the players:

Actin, tropomyosin, troponin complex, Ca(2+) binding sites, Ca(2+), & myosin binding sites.

What does calcium (Ca2+) do to allow myosin heads to bind to the actin?

Ca(2+) binds to the troponin complex, causing the myosin-binding sites on actin to be exposed.

Name the two other types of muscle (beside skeletal):

Cardiac muscle & smooth muscle.

Which one is striated (like skeletal muscle)?

Cardiac muscle.

Where would you find smooth muscle?

It is found mainly in the walls of hollow organs, such as vessels and tracts of the circulatory, digestive, and reproductive systems.