Exam 4

Circulation & Gas exchange:
• Distinguish between blood and hemolymph
• List and define the major types of blood vessels – sketch a simple circuit to show how they are connected.
Identify which vessels allow for gas exchange.
• Describe the different adaptations for bringing oxygen into the body –cutaneous exchange, gills, lungs. What
features of each allow for efficient exchange?
• Describe the relationship between the surface area-to-volume ratio and efficiency of exchange across a
surface.
• In a two-chambered (fish) heart, where does the blood go after it leaves the atrium? (Give the entire
pathway ending back in the atrium). What happens as it passes through the capillary beds in the tissues
and in the gills? Contrast this with the 4-chambered heart/double-circuit system below.
• In a four-chambered heart, where does the blood go after it leaves the right atrium? (Give the entire
pathway ending back in the right atrium). What happens as it passes through the capillary beds in the
systemic and in the pulmonary circuits?
• Identify which parts of the pathways you outlined above carry oxygenated blood ... and which carry de-
oxygenated blood.
• Describe what is meant by “counter-current exchange/flow”. Contrast it with co-current exchange.
• Explain how counter-current flow allows blood to pick up more oxygen than co-current flow would.
• Know that animals use counter-current flow and not co-current flow.

• What is the role of hemoglobin?
• Explain the relationship between the partial pressure of oxygen in the tissues and how much O2 will be released
to them. Interpret the oxygen saturation curve we explored in lecture and the LBL.
• What is the Bohr shift and how does it work? How is it adaptive for supplying tissues that are working hard
with more oxygen?
Osmoregulation and Excretion
• What mechanisms are found in animals to conserve water?
• Where does N-waste come from?
• Name the three forms of nitrogenous waste found in animals.
o Which of these nitrogenous wastes is least energetically expensive and most energetically expensive
to produce? Which are most/least toxic?
• Name/label the parts of the vertebrate nephron and indicate where it is permeable to water and where salt is
pumped out.
• Relate the movement of different molecules to changes in the filtrate.
• How does the increasing osmolarity of the interstitial fluid help maximize the removal of water from the
filtrate?
• How does the filtrate become more concentrated as it travels the descending loop of Henle? How does it
become more dilute as it travels the ascending loop of Henle? How does it become more concentrated as
it travels the collecting duct?
• How does the reabsorption of urea into the interstitial fluid surrounding the loop of Henle allow for an
increased ability to pull water out of the nephron?
• How does antidiuretic hormone control water absorption in the collecting duct?
• Describe the two other nephrons your read about – the protonephridium and the metanephridium. Which
phyla have these? Remember that the metanephridium is one of the metameric structures we discussed in the
Annelida.
Nerves
• What is the role of the nervous system?
• What is the difference between a “neuron” and a “nerve”?
• Identify the concentration gradients for the following ions: Na+, K+. Ca++.
• Sketch and label a single neuron – be sure to label all 4 parts.
• Describe the location of voltage-sensitive gated channels versus the location of chemically-sensitive
gated channels – where would you find each within the nerve/synapse?
• Apply the terms to the dynamics of nerve signal transmission:
o Resting potential, action potential
o Depolarization, hyperpolarization, repolarization.
o What is meant by “threshold”? Relate this to how action potentials are “all or nothing”.
• Describe the mechanisms that prevent an action potential from going backwards (the refractory period)
• Explain in detail how action potentials are propagated along an axon including the types and structure
of the ion gates/pumps. Include the activation & inactivation gates associated with the Na+ channels.
• Revisit the in-class worksheet (and lab) – be able to sketch the neuron set up, label the action potential
diagram of voltage changes, identify what gates are open/closed at each of the labeled parts (a-e).
• Which ion gates open at the axon terminus?
• What does calcium do in the axon terminus?
• What is a synaptic vesicle? What role does it play in passing the signal from to another cell?

• Describe all the steps involved in passing the signal from the pre-synaptic nerve to the post-synaptic
nerve. Include the role of calcium ions and neurotransmitters.
• What is the role of the Hillock in the post-synaptic nerve?
• Define the terms EPSP and IPSP – what does each stand for and what does each mean?
• Determine whether or not a post-synaptic cell will experience an EPSP or an IPSP, if it will depolarize or
hyperpolarize if given a scenario.
• Outline the different ways a post-synaptic cell might receive incoming stimuli and how that relates to
whether it reaches threshold or not – focus on temporal and spatial summation.
• What is the function of a Schwann cell? (LBL)
• Differentiate between the “peripheral nervous system” and the “central nervous system”.
Muscles
• Name the three types of muscle and indicate where each is found (in general).
o Make connections with other class topics: Which type of muscle is associated with arteries and
veins? With the digestive tract? The heart?
• Label a diagram (or slide) of striated muscle showing the following:
Z-lines, Actin, Myosin, Troponin, Tropomyosin, Calcium receptors.
• Give a blow-by-blow account of muscle contraction and relaxation including all of the key players.
o Actin, myosin, Z-lines, troponin, tropomyosin, calcium, sarcoplasmic reticulum,
• Be clear on the energy cycle that drives contraction – what is the role of ATP and ADP+P in the binding
and unbinding of myosin to actin? Pay attention here – it is not intuitive.