Biology 2 - Exam 2

The humoral immune system: details about antibodies? What are they? What are they made of?

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What is the "driving force" for the various ions at resting Vm?

-"driving force" is the difference between E for that ion and the membrane potential -For diagram, arrow sizes indicate strength of driving force

Neuron anatomy? How many neurons are there in a human's brain?

-100 billion

How many synapses for each neuron's dendrites? How many neurons in the brain and how many synapses?

-1000 synapses -10^11 neurons -10^14 synapses

Ethylene-signaling pathway in the absence and presence of ethylene?

-Absence (top image): the ethylene receptors (ETR1) activate the CTR1 protein kinase, which phosphorylates EIN2 and prevents its cleavage. In the nucleus, EBF1/2 proteins target the TFs EIN3/EIL1 for ubiquitylation and degradation so that EIN3/EIL1 are degraded -Presence (bottom image: the ligand-bound ethylene receptors no longer activate CTR1, resulting in the proteolytic release of the C-terminal end of EIN2 ("C-END"), which inhibits protein translation of EBF1/2 proteins. Therefore, EBF1/2 levels decrease and EIN3/EIL1 are consequently stabilized, thereby turning on an extensive transcriptional cascade involving the TF ERF1`

What is active immunity? What is passive immunity?

-Active immunity: acquiring an immune response within the organism by inoculation with an antigen -Passive immunity: transferring antibodies from a person/organism who is immune to someone who is not, examples: a) across placenta b) in mother's milk c) anti-toxins (eg, antibodies to snake venom or to toxins produced by bacteria or fungi) d) antibody against the rabies virus that is administered only once to provide immediate antibodies until the body can respond on its own

How did African Lungfish develop a lung? What about their heart is different than normal fish?

-African lungfish evolved a primitive lung from an outpocketing of the gut -a pair of modified gill arteries direct some of the blood coming from the heart to the lung, and a new vessel carries oxygenated blood from the lung back to the heart -the lungfish heart has divided atria; the blood streams stay mostly separate as they go through the partially divided ventricle. Oxygenated blood goes mostly to the body; deoxygenated blood goes to the lung

What are blood cells made from?

-Blood cells are made from pluripotent stem cells in the bone marrow. They include lymphocytes, monocytes, etc., and erythrocytes (RBCs), and platelets

Example of a g-protein coupled metabotropic receptor?

-Cardiac adrenergic receptor (heart cells)

How are animals classified according to the sources of heat that determine their body temperature?

-Ectotherms (most animals aside from mammals and birds) depend on external heat sources to maintain body temperature. (For poikilotherms or "cold-blooded" animals, body temperature changes when environmental temperature changes if the animal cannot regulate its body temperature behaviorally) -Endotherms (all mammals and birds) regulate body temperature by generating metabolic heat and/or preventing heat loss

Issues with vaccination?

-Edible vaccines, from transgenic plants -Use clean needles: smallpox vaccinations and the spread of AIDS -Is the pathogenic antigen stable? (eg, polio, tetanus, diptheria) or unstable due to continuous evolution?(eg, flu, cold, HIV) -it is important for all children to be immunized- vaccination avoiders are dangerous to themselves and to the rest of us

What is the idea of Phrenology and who did it come from?

-Franz Joseph Gall suggested that the brain was divided into 27 separate "organs." Each organ supposedly corresponded to a discrete human faculty. He gradually reached the strong conviction- not only that the talents and dispositions of men are dependent upon the functions of the brain--but also that they might be inferred precisely from the external appearances of the skull

The immune system has two responses against invaders?

-Humoral immune response: involves antibodies that recognize antigenic determinants by shape and composition. Most antibodies are soluble proteins that travel freely in the blood and lymph. Antibodies also reside as integral membrane proteins on B cells to function as receptors that sense antigens -Cellular immune response: detects antigens that reside within cells, using T-cells to destroy virus-infected or mutated cells

Behavior- imprinting?

-Imprinting is a type of learning in which animals learn, during a critical period, a complex set of stimuli that later act as releasers. the ethologist Lorenz showed that newly hatched goslings imprint on the image of the first object they see (normally their parent, but under experimental conditions, Lorenz or his assistants), and that subsequent exposure to the object releases the goslings' following behavior

Thermoregulation: losing heat. Endotherm regulation in hot climates? Problem?

-In hot climates, endotherms have the opposite problem: losing heat. 1) reduction or loss of fur or hair allows for easier heat loss from the body to the environment 2) increase the extent of appendages 3) seeking contact with water cools the skin because the water absorbs heat to a greater capacity than air does 4) sweating or panting to increase evaporation provides cooling

Treatments for Parkinson's Disease (PD)? Experiments in rats?

-L-dopa: as a precursor to dopamine, it can boost dopamine production -initial treatment with L-DOPA (levodopa) and when L-DOPA becomes less effective, with dopamine agonists. As PD progresses and more SN neurons die, the medications become less effective and cause unpleasant side effects -these treatments are "sledgehammers" and have other effects, such as on memory -experiments in rats: embryonic stem cells can be stimulated to develop into dopamine-secreting neurons. When these cells were transplanted into the brains of rats with PD-like condition, the rats recovered motor control

Brain: parts/functions?

-Medulla and pons ("primitive hindbrain"): control physical functions (eg breathing and circulation) -Cerebellum coordinates motor commands to muscles -Diencephalon is the core of the "forebrain", and includes the thalamus, hippocampus, hypothalamus, and posterior pituitary -Telencephalon (cerebrum) consists of two cerebral hemispheres, left and right. In humans, the telencephalon is the largest part of the brain and plays major roles in sensory perception, learning, memory, and conscious behavior

Where do these "cell wars" take place? At sites along lymph vessels?

-Much of the action takes place in the fluid tissues: -Blood -Lymph: consists of fluids that accumulate outside of the closed circulatory system. The lymphatic system is a branching system of tiny capillaries connecting larger vessels with valves and containing lymph fluid (lymph vessels have valves that are analogous to those in veins). Lymph fluid contains white blood cells and platelets, but not RBCs -at sites along lymph vessels are small, lymph nodes, where phagocytic cells remove microbes and foreign matter

Synapses between neurons: EPSPs and IPSPs?

-NTs that depolarize the postsynaptic membrane are excitatory and bring about an excitatory postsynaptic potential (EPSP). This EPSP might not be strong enough to single-handedly elicit an action potential in the postsynaptic cell -NTs that hyperpolarize the postsynaptic cell are inhibitory and bring about an inhibitory postsynaptic potential (IPSP)

How do pumps maintain the ion concentration gradient?

-Na+/K+ pump uses ATP to move 3 Na+ out, 2K+ in -the Na+/K+ pump maintains the ionic concentration gradients that create Vm -Even if the Na+/K+ pump maintains the ionic concentration gradients last for a long time and the Vm stays at -60 mV for a long time. Even thousands of action potentials can be stimulated in the pump-poisoned neurons until the ionic concentration gradient runs down

Drugs and the neuromuscular junction: curare?

-Native South American tribesman used to dip their arrowpoints in a poison called curare (a plant extract) -curare paralyses muscles by blocking ACh from reaching its receptors; no ACh means no contraction -death occurs because the muscles that move the diaphragm become paralyzed. Breathing stops and the victim asphyxiates

Behavior- orientation, bin experiment results?

-Results: birds whose biological clock was delayed by 6 hours (ie lights came on in the experimental chamber 6 hours after the natural dawn) looked for food in the wrong direction when tested in an arena under natural sunlight -these birds were using a biological clock-compensated sun compass

Rods versus cones? (Difference)

-Rod cells are more sensitive to very low intensities of light (provide high sensitivity B&W vision) -Cone cells respond to different wavelengths of light for color vision. Cones also provide the sharpest vision. The fovea has only cone cells.

What is the most abundant protein on the earth? Most abundant membrane?

-Rubisco: fixes carbon in the Calvin Cycle of photosynthesis; constitutes 50% of all protein in the leaf -most abundant membranes are thylakoid membranes

Simple animals versus vertebrates?

-Simple animals: process information with a simple network of neurons (nerve net). The next level of nervous system complexity includes clusters of neurons called ganglia -Vertebrates: most of the cells of the nervous system are found in the brain and in the spinal cord, which together are called the central nervous system (CNS). The rest is peripheral nervous system (PNS)

Applications of circadian rhythms in humans? Sleep/wake, industrial applications, and medical applications?

-Sleep/wake: 1) insomnia (esp in elderly) 2) napping 3) jet lag (discomfort, cognition, and alertness problems) -Industrial applications: 1) shift-work (alertness, performance, injuries) 2) industrial accidents (eg airplanes, nuclear power plants) -Medical applications: 1) health problems related to shiftwork 2) drug responses: "chrono-pharmacology" 3) mistakes made by tired doctors/nurses 4) affective disorders such as major depression and seasonal affective disorder (SAD) 5) metabolic issues related to daily timing of meals and snacks (implications for obesity and diabetes)

Two main groups of white blood cells? Two main types of lymphocytes? What do they do?

-There are two main groups of WBCs: phagocytes, and lymphocytes -There are two types of lymphocytes: B and T cells, both of which differentiate from pluripotent stem cells in the bone marrow (lymphoid stem cells) -T cells migrate to the thymus, where they mature -B cells circulate and also connect in lymph vessels, and make antibodies

Behavior- spatial learning? Digger wasp experiment?

-Tinbergen also studied spatial learning in digger wasps by placing pine cones around the entrance of a female's nest, then moving the pine cones a short distance away once she left the nest -upon returning, the female oriented to the moved pine cones and could not find her nest entrance. The female wasp had learned to recognize and use objects in the environment as orientation cues to find her nest

Vaccination or immunization can be accomplished by? What are booster shots? What does immunization initiate? What are attenuated antigens? Antigenic fragments

-Vaccination or immunization can be accomplished by inoculation with whole pathogens (modified/attenuated so they cannot cause disease) and/or with antigenic proteins, pathogen fragments, or other molecular antigens -immunization and vaccination initiates a primary immune response that generates memory cells without making the person ill: -attenuated antigens reduce the toxicity of the antigenic molecule or organism (fixed or killed) -biotechnology can produce antigenic fragments (epitopes) that activate lymphocytes but do not have the harmful part of the cell-surface protein or toxin

What is receptor potential and how does it work?

-a change in the membrane potential of a sensory cell in response to a stimulus. -figure is a stretch receptor example

What is a closed circulatory system? Earthworm example?

-a closed circulatory system keeps the blood and tissue fluid separate. One or more muscular hearts and a branching network of vessels (the vascular system) move the blood -the earthworm has a closed circulatory system. The large dorsal and ventral vessels are connected by 5 contractile vessels that serve as hearts. Direction of blood flow is controlled by one-way valves

What is Parkinson's Disease (PD)?

-a common neurodegenerative disease (about 1% of all people > 65) -major symptoms: tremor, muscle rigidity and weakness, speech difficulties, dementia, and a blank, mask like facial expression -these symptoms are caused by the progressive degeneration of dopamine-containing neurons in a part of the brain called the substancia nigra (SN)

Thermoregulation: fevers?

-a fever is a rise in body temperature in response to pyrogens. Exogenous pyrogens come from foreign substances such as invading bacteria or viruses. Endogenous pyrogens are produced by cells of the immune system when they are challenged (eg, by macrophages during the inflammation response) -pyrogens cause a resetting of the hypothalamic "set-point", and body temperature rises until it matches the new set-point. Low-grade fevers may help to combat pathogens such as bacteria, but high sustained fevers can be very dangerous and cause irreversible brain damage

Behavior- fixed action patterns and releasers?

-a fixed action pattern is an instinctive behavioral sequence in response to an external sensory stimulus known as a Releaser (aka sign stimulus) -releasers are usually a simple sensory cue -eg, in herring gulls, chicks peck at the red dot at the end of their parent's bill, and the parent regurgitates food

What does mammalian blood consist of? Tissue fluid?

-a fluid matrix (plasma) and cells: red blood cells (RBCs, aka erythrocytes), white blood cells (aka leukocytes), and platelets (cell fragments) -our cells are bathed by tissue fluid, which is basically the plasma portion of blood without the large molecules. This tissue is moved by the lymphatic system

Giraffe example with high blood pressure? How would you predict the walls of the arteries to compare to humans?

-a giraffe has to pump blood 2.5 meters above the heart. This requires a systolic pressure of 250 mm Hg. In humans, blood pressure this high would cause hypertension and damaged vessels. (Healthy human is systolic 120 mm Hg) -the walls would be thicker

How do actin and myosin form myofibrils?

-a myosin filament is made of many myosin molecules arranged in parallel: each myosin molecule consists of two long polypeptide chains coiled together, each ending in a large globular head. The heads have sites that bind to actin, forming bridges between the actin and myosin. Myosin heads have ATPase activity

Behavior- dance of honeybees? A type of dance when food source is less than 80m from hive?

-a successful foraging honeybee returns to the hive and communicates by dancing in the dark on a vertical surface within the hive. As she dances, her hivemates monitor her movements through touch and interpret her message -if the food source is less than 80m from the hive, the bee dances the "round dance". The odor on the bee's body helps to provide information about the kind of flower to look for

How does a vertebrate speed up action potentials? Where are ion channels clustered? How is saltatory conduction fast? What speeds can saltatory conduction allow?

-a vertebrate strategy to speed up action-potentials- insulation by myelin sheaths (from Schwann cells in the PNS) that reduce ion leakage and therefore allows "saltatory" conduction -Ion channels are clustered at the nodes of Ranvier. When an action potential fires at one node of Ranvier, it jumps to the next via saltatory conduction -Saltatory conduction is fast because: 1) electrical (ionic) current travels quickly through the cytoplasm if there are no leakages 2) fewer ion channels are opening and closing, therefore less time is required for ion channels to open and close -saltatory conduction allows speeds up to 120 m/s

Contraction of sarcomeres?

-actin and myosin slide past each other as the muscle contracts -the Huxley's called this mechanism the "sliding filament" theory of muscle contraction -when a muscle contracts, the sarcomere shortens, the H zone and the I band become much narrower, and the Z lines move toward the A band as the actin filaments slide into the region previously occupied only by the myosin filaments

Neuromuscular junction?

-action potential (NA+/K+ mediated) arrives at axon terminus -depolarization at terminus opens voltage-gated Ca++ channels -synaptic vesicles fuse with membrane, releasing NT (ACh) -if the depolarization is strong enough to exceed the threshold, it will trigger an action potential in the postsynaptic cell; in the case of a muscle cell, the action potential will elicit a contraction -if the postsynaptic cell is a neuron, the end result is more complex

T-tubules and sarcoplasmic reticulum (SR)?

-action potentials in muscle fibers also travel deep within the cell. The plasma membrane is continuous with a system of tubules that branch through the cytoplasm, called "T tubules" -T-tubules run close to a network of intracellular membranes called the sarcoplasmic reticulum (SR), which is a modified ER that is specialized in muscle cells as a Ca++ store -at rest, there is a high concentration of Ca++ in the SR and a low concentration in the cytoplasm

Types of muscles in vertebrates? What do they all use?

-all use actin and myosin, but they are controlled and organized differently

Results of the Stanford Undergraduate Sleep Deprivation study?

-allowed and forbidden phases for sleep: no matter how tired we are, sleep is not allowed by the circadian clock at some phases -this was shown by an experiment done by undergraduate students in a class at Stanford. Some of the students (the subjects) were forced to stay on the following cycle:

What is multiple sclerosis?

-an autoimmune disease in which the myelin sheaths are attacked by the immune system -once the myelin is damaged, signals from cells do not travel as efficiently, leading to MS attacks -symptoms vary and can include numbness, poor coordination, poor vision, and paralysis

How do anesthetics act on the nervous system? How does tetrodotoxin tie in?

-anesthetics like novocaine and lidocaine stop action potentials and act locally. By appropriate use of dose and injection site, specific regions can be anesthetized -some researchers are making chemical modifications of poisons like tetrodotoxin and curare in an attempt to create highly specific and reversible anesthetics and/or pain killers

Behavior- orientation? "Clock-shifting" experiments?

-animals can use the sun and the stars to determine direction. The sun is an excellent compass, provided the time of day is known. Animals can determine time of day from their circadian (daily) biological clocks -"clock-shifting" experiments have shown that birds use their circadian clocks to determine direction from: a) time of day, and b) the position of the sun -Experiment: a bird is placed in a circular cage (arena) from which it can see the sun and sky but no other visual cues and is trained to expect food in a bin at a certain position (=direction)

Immune system: specificity?

-antigens are organisms or molecules that are specifically recognized by antibodies and/or T cell receptors -the sites on antigens that the immune system recognizes are the antigenic determinants (or epitopes). -each antigen typically has several different epitopes -the host selects for T cells and/or antibodies that are specific to the antigenic determinants -antigen = antibody generating molecule

Where and when do aortic aneurisms occur? What are most caused by?

-aortic aneurisms occur when the wall of the aorta weakens and balloons outward. Sometimes the iliac artery may also be affected. The aneurism can grow larger and eventually rupture if not diagnosed and treated -most aneurisms are caused by a breakdown in the structural proteins in the wall of the aorta. While these proteins can gradually deteriorate with age, some conditions can accelerate the process, including atherosclerosis

What is aphasia? People suffering from damage to Broca's area and Wernecke's area?

-aphasia is an impairment of the ability to produce and/or comprehend language, due to brain damage -people suffering from damage to Broca's area may be unable to create grammatically-complex sentences: their speech is often described as telegraphic and contains little but content words. Patients are usually aware that they cannot speak properly -Wernicke's aphasia is characterized by damage to more posterior regions of the left hemisphere. Wernicke's aphasia results in a more pronounced impairment of comprehension. Thus, while speech production remains normal grammatically, it is nonetheless often roundabout, vague or meaningless

Cardiac muscle?

-are branched into a meshwork; they appear striated because of the regular arrangement of their actin and myosin filaments -cardiac muscle cells are in electrical contact with one another by gap junctions, and depolarizations begun at one point in the heart rapidly spread through the muscle mass -although heart activity is modified by the autonomic nervous system, the heart will beat without nervous input because of special pacemaker muscle cells that have a self-generated heartbeat

Type 2b white fibers?

-are fast glycolytic (also called fast twitch B or fatigable fibers): -low myoglobin content (therefore "white") -few mitochondria -few blood capillaries -large amount of glycogen -splits ATP very quickly -fatigues easily -needed for sports like sprinting

Type 2a red fibers?

-are fast oxidative (also called fast twitch A or fatigue resistant fibers): -large amounts of myoglobin (therefore "red") -many mitochondria -many blood capillaries -high capacity for generating ATP by oxidation and splits ATP at a very rapid rate -resistant to fatigue but not as much as slow oxidative fibers -needed for sports such as middle distance running and swimming

What are glial Schwann cells?

-are in the peripheral nervous system -while oligodendrocytes are in the CNS -both produce myelin sheaths to insulate neurons

Type 1 red fibers?

-are slow oxidative (also called slow twitch or fatigue resistant fibers): -large amounts of myoglobin (therefore, "red") -many mitochondria -many blood capillaries -high capacity for generating ATP by oxidation, but split ATP at a slow rate -slow contraction velocity -resistant to fatigue -needed for aerobic activities like long distance running

Smooth muscle? What does it do?

-are the simplest muscle cells -single nucleus per cell -spindle-shaped -often in smooth sheets -not "striated" because the actin and myosin are not arranged regularly within the cell as is true for cardiac and skeletal muscle cells -smooth muscle does-- moves food through digestive tract (involuntary contractions); controls the flow of blood (surrounds blood vessels); empties the urinary bladder

Sensory receptors: vision (eyes) in arthropods?

-arthropods have compound eyes consisting of many optical units called ommatidia -each ommatidium has a lens that directs light onto photoreceptor cells (retinula cells). -the retinula cells contain rhodopsin and their axons communicate with the nervous system -the number of ommatidium varies in species, from a few in ants to 10,000 in dragonflies

In addition to colloidal osmotic pressure, how do CO2 and bicarbonate ions (HCO3-) pull water back into the capillaries?

-as blood flows through the capillary, CO2 diffuses into the plasma and RBCs and is converted into HCO3-. This HCO3- provides additional osmotic pressure for water to flow back into the capillaries at the venous end

What does the topic of salycylic acid as a hormone introduces what?

-auxins: promote stem elongation, adventitious root initiation, and fruit growth; inhibit lateral bud outgrowth and leaf abscission -ethylene: promotes fruit ripening and leaf abscission; inhibits stem elongation and gravitropism

How can the classes of EIN and CTR mutants be explained?

-because CTR components are repressors of the Triple Response, deleterious mutants in these components lead to an "on" response even in the absence of ethylene -because EIN components are necessary for Triple Response to occur, deleterious mutants in these components lead to an "off" response even in the presence of ethylene

Thermoregulation: because of a large surface/volume ratios, what happens to endotherms (small and large)? Example of Shrews? What is suggests for dinosaurs?

-because of large surface/volume ratios, small endotherms lose heat much more rapidly than large endotherms, so their basal metabolic rate is much higher. -shrews must eat almost continuously to survive, and go into torpor when asleep or inactive. -this surface:volume argument has led some scientists to suggest that huge dinosaurs may have been able to retain so much heat (like massive elephants) that they were effectively endotherms (more recently, they have been characterized as mesothermic)

How does making transgenic plants work so well?

-because the infection Agrobacterium is efficient and because entire plants of many species can be regenerated from calli tissue (we mentioned this before in the context of totipotency)

Advantages of closed circulatory system over open?

-blood flow, nutrient delivery and waste removal are more rapid -closed systems can regulate blood flow to specific tissues -cellular elements and large molecules that air in transport can be kept within the vessels

How does clotting work?

-blood vessel damage exposes collagen fibers, which activates the platelets -the swelling, sticky platelets release clotting factors that activate other platelets and initiates clotting -vessel damage and platelet activation lead to conversion of inactive factors (prothrombin) to active forms (thrombin), that cause the polymerization of inactive fibrinogen into fibrin "threads" -fibrin threads form a meshwork to stabilize the plug and provide a base for scar tissue

Botulism and Botox?

-botulism is food poison from ingesting neurotoxin produced by the bacterium Clostridium botulinum -botulism causes paralysis (leading to death). The botulinum toxins (there are seven types: A-G) attach themselves to proteins necessary for ACh release at neuromuscular junctions, blocking ACh release -Botulinum toxin A affects a presynaptic release protein SNAP-25. Botox is a trade name for botulinum toxin A -at low doses, within a few hours to a couple of days after the botulinum toxin is injected into a muscle, contractions are reduced or eliminated altogether. The effects of the treatment are not permanent, reportedly lasting anywhere from 2 to 8 months. By injecting the toxin directly into a certain muscle or muscle group, the risk of it spreading to other areas of the body is diminished

How does auxin promote cell growth?

-by acting on cell walls -cell walls are composed of cellulose, a large polymer of glucose, and a few other components -cellulose molecules tend to form parallel associations. Microfibrils are composed of about 250 parallel cellulose molecules. Networks of microfibrils connected by bridges of smaller polysaccharides make cell walls rigid.

What can control the surface temperature of an animal? What happens when blood is close to the surface of the skin? What happens when a person is exposed to the cold? What is vasoconstriction and vasodilation in arterioles controlled by?

-can be controlled by altering the blood flow to the skin -blushing; heat is lost to the environment -when a person is exposed to the cold, blood vessels of the skin constrict, decreasing blood flow and heat transport to the skin and reducing heat loss -vasoconstriction in arterioles is controlled by the endothelial factor endothelin and vasodilation is controlled by NO

Darwin experiments with canary grass seedlings?

-canary grass seedling grown in the dark and then exposed to directional light -found that when the top millimeter of the coleoptile of a grass plant is covered, the plant cannot respond to the direction of light -the photoreceptors are in the coleoptile tip. However, the bending takes place in the growing region below the tip. A signal must pass from the tip to the growing region. Phototropism is a result of differential growth in the direction of the light.

Anatomy of capillary beds/ its surroundings? General information about capillaries?

-capillary beds lie between arterioles and venules and exchange materials between blood and tissue fluid through their thin walls. Blood flows slowly in the capillaries, facilitating this exchange -capillaries in the brain, kidneys, and liver are usually completely full, but in other places, the blood supply is highly regulated. In these other tissues, ~5-10% of the capillaries have blood flowing through them at any given time. However, each tissue has many capillaries, so every part of the body is supplied with blood at all times

What are capillary walls? Leakage? Blood pressure and osmotic pressure? Lymphatic system?

-capillary walls are a single layer of epithelial cells and have fine holes, called fenestrations -many small molecules leak through, but larger protein molecules are retained -blood pressure squeezes water and small solutes out of the capillaries; osmotic pressure created created by the large protein molecules in the capillary (colloidal osmotic pressure) and by bicarbonate (HCO3-) draws water back into the capillary -fluid and proteins that do not re-enter the capillary system (about 15%) are recovered by the lymphatic system

How does cardiac muscle and contraction work? How is it an electrical circuit? What is the primary pacemaker of the heart? How does a normal heartbeat begin? Why don't the ventricles beat in unison with the atria?

-cardiac muscle cells are myogenic (spontaneously contract) and are electrically coupled by gap junctions to allow coordinated contractions -the primary "pacemaker" of the heart is the sinoatrial node (SA) located at the juncture of the superior vena cava and the right atrium -a normal heartbeat begins with an action potential in the SA that spreads through the atrial cells, causing them to contract in unison -the ventricles do not contract in unison with the atria because there are no gap junctions between the cells of the atria and ventricles -(The SA pacemaker will intrinsically stimulate rhythmic contractions of the heart, but nerve input to the pacemaker from the brain can speed up or slow down this intrinsic rhythm)

Cerebral cortex? Detailed example of temporal lobes?

-cerebral cortex: higher-order information processing; different regions of the cerebral cortex have specific functions -the temporal lobes are involved in the recognition, identification, and naming of objects. Damage to the temporal lobe results in disorders in which the individual is aware of a stimulus but cannot identify it

Behavior- chemical communication? Examples?

-chemical communication can occur via pheromones (usually odor molecules that can convey specific messages between individuals) -an example is the pheromone released by female silkworm moths to attract males -territory marking by cats and other mammals can provide information on the species, individual identity, reproductive status, size, and when the animal was last in the area

What are circulatory adaptations? What does vasodilation do? What does vasoconstriction do?

-circulatory adaptations are adaptations that regulate the extent of blood flow near the body surface or that trap heat within the body core -vasodilation in skin increases the transfer of body heat to the environment through conduction, convection, and radiation -vasoconstriction in skin deceases the transfer of body heat to the environment through conduction, convection, and radiation

Psychoactive drugs: cocaine? LSD? Amphetamines?

-cocaine: inhibits dopamine and norepinephrine transporter -LSD: serotonin agonist -Amphetamines ("speed"): induces release of dopamine and inhibits transport; produces symptoms very similar to those of schizophrenia

Behavior- touch communication? What did studies by Karl von Frisch reveal?

-communication by touch is very common among animals, particularly when conditions are poor for visual communication -studies by Karl von Frisch revealed the role of tactile communication in the "dance" of honeybees

Behavior- communication?

-communication is behavior that influences the actions of other individuals -displays or other signals transmit information that benefits the sender and the receiver -there are five modes of communication: chemical, visual, auditory, tactile, and electric -these modes differ in their effectiveness in different environments

Circadian rhythm of core body temperature?

-constant bedrest routine with indwelling rectal thermometer:

How do motor neurons stimulate skeletal muscle contraction?

-contractions in skeletal muscle are stimulated by action potentials from motor neurons -each motor neuron branches and synapses with up to a hundred muscle fibers. These fibers constitute a motor unit -muscle fibers are excitable and are depolarized by a threshold action potential -this opens sodium channels, permitting the muscle plasma membrane to generate action potentials just like the axon of the delivering neuron

What is countercurrent exchange? What does it allow?

-countercurrent exchange is the transfer of heat (or solutes) between fluids that are flowing in opposite directions -it allows for heat exchange between arteries and veins that are traveling in opposite directions

FDA-approved uses of botox?

-crossed eyes, eyelid spasms, severe neck spasms, severe underarm sweating, upper-limb/ or lower-limb spasticity, chronic migraine prevention, overactive bladder

How can stuff get past barriers?

-cuts, punctures -inhalation, ingestion

deMairan's experiment using Mimosa (1729)?

-daily rhythms of "sleep movements" of leaves: evidence for an endogenous biological clock (a "circadian rhythm")

Rod cells in dark and light (regarding glutamate)? What are the two types of bipolar cells?

-dark: depolarized photoreceptor cells release glutamate (as a neurotransmitter) continuously onto the bipolar cells upon which they synapse -light: hyperpolarized photoreceptor cells stop releasing glutamate -Two types of bipolar cells: 1) Type 1: are depolarized by the glutamate, and hyperpolarize in the light (we'll ignore this type, which has ionotropic receptors 2) Type 2: have metabotropic receptors for Cl- channels. When glutamate is released, the Cl- channel in the bipolar cell is open, therefore the bipolar cell is hyperpolarized (darkness). When glutamate is not released, the metabotropic receptor turns off, closing the Cl- channel, causing the bipolar cell to depolarize and fire an action potential

What does a depolarized bipolar cell fire?

-depolarized bipolar cells fire an action potential that releases neurotransmitter onto the ganglion cells, which fire an action potential that goes down the optic nerve to the brain

Depression symptoms? One class of antidepressants?

-depressed mood most of day; markedly diminished interest or pleasure in activities; significant weight loss or weight gain unrelated to dieting; insomnia or hypersomnia; fatigue or loss of energy; feelings of worthlessness or guilt; diminished ability to concentrate; recurrent thoughts of death -one class of antidepressants are called SSRIs (selective serotonin reuptake inhibitors) and include Prozac and Paxil. SSRIs inhibit serotonin reuptake, thereby increasing the time that serotonin lingers in the synaptic cleft after release. This may have the effect of increasing the effective serotonin signal at synapses

What do sensory systems represent?

-don't represent reality but what is important for survival and fitness. Perception of changes or differences in the environment are emphasized

What does prayer and meditation do?

-during meditation, praying, chanting, liturgies: there is a blurring of the boundaries of self, opening the door to "unitary" states -prayer and meditation increases the amount of activity in the front part of the brain and decreases activity in the area of the brain that orients our bodies in space. Increased frontal activity is not only during meditation, but also during other attention-focusing tasks -decreased activity in the orientation area is believed to be related to the changes in spatial perception and the loss of a sense of self that are associated with meditative states

An example of neural plasticity?

-each finger has a specific location on the sensory and motor regions of the cortex. In monkeys, one middle finger was amputated and after several weeks, the area of the cortex that had been dedicated to the middle finger was re-assigned to other fingers

Skeletal muscle: each muscle fiber is packed with what?

-each muscle fiber (= single cell) is packed with bundles of myofibrils, each made up of thin actin units surrounding thick myosin units

Immune system: distinguishing self from non-self?

-each normal cell and protein in the body bears a tremendous number of potential epitopes. It is crucial that the immune system leave these alone

What is the Clonal Selection Theory?

-each of us has a great variety of B cells and T cells, each of which can respond specifically to only one antigenic epitope -normally, the number of any given type of B cell is relatively low -when a B cell binds the antigen that is specific for its antibody (receptor), the B cell divides and differentiates into plasma cells (which produce and secrete antibodies) and memory cells -thus, an antigen "selects" and activates a particular antibody-producing cells

What can ectotherms and endotherms do to regulate body temperature? Examples?

-ectotherms such as lizards can use behavior to regulate body temperature in the natural environment -behaviors include basking in the sun, seeking shade, burrowing, or orienting body with respect to the sun -endotherms also use behavioral thermoregulation. Most animals select the best thermal environment whenever possible. For example, by seeking shelter, insulation, shade, breezes, etc

Where did our understanding of how nerve cells in the brain generate electrical signals originate from?

-electrical signals are action potentials -originated from studies on a "giant" squid neuron

What is transgenic Cassava? Example with cotton? Rice?

-enrichment with protein, iron, beta-carotene, and elimination of cyanide production -edible cotton seeds: cotton seeds are poisonous due to high levels of the toxin gossypol. Newly engineered cotton plants express only low levels of gossypol that allow the peanut-sized seeds to be eaten safely -rice with beta-carotene

Behavior- releasers? Red dot hypothesis/ experiment?

-ethologists Tinbergen and Perdeck hypothesized that the red dot was a releaser for begging in chicks. To test the hypothesis, they presented chicks with artificial models of gull heads that differed in color, shape, and presence of the red dot on the bill, and counted pecking responses of the chicks

Evaporative cooling? What type of process is it? Examples?

-evaporative cooling is the removal of heat from the surface of a liquid that is losing some of its molecules as vapor -evaporation is an endothermic process (ie, heat is absorbed during evaporation) -examples: bathing, sweating, panting

Sensory systems: vision (eyes)?

-evolution has conserved molecules used for photosensitivity across animal species (and even some plants). These are a family of pigments called rhodopsins. They are composed of pigment (retinal) bound to a protein (opsin; a 7-transmembrane domain protein) -light causes retinal to change from the 11-cis form to the all-trans form, which induces a change in the conformation of opsin -photoexcited rhodopsin triggers a cascade that alters the membrane potential of the photoreceptor cell

Behavior- orientation, bin experiment? And prediction?

-example: a bird is trained to expect food in the south bin. When tested in the arena at 9am, it turns to right of the sun. When tested at 3pm (=15:00), it turns to left of the sun -then the bird is exposed to an "artificial" light/dark cycle in the lab that starts 6 hours after natural dawn. This resets the internal biological clock. Then the bird is retested in the arena that is exposed to the sun -if the bird is using its biological clock (now phase-shifted) and the sun's position to tell the direction, it will go in the wrong direction -Prediction: if phase-delayed by 6 hours and tested at 3pm, the bird "thinks" it is 9am and it turns right, ie to the west (but south is to the left at 3pm)

Excitatory and inhibitory influences?

-excitatory and inhibitory postsynaptic potentials are summed spatially and temporally -each neuron is a tiny "computer" that is integrating excitatory and inhibitory inputs to "decide" whether to initiate an action potential (digital output)

Twitching and physiological tetanus?

-faster twitching of individual fibers causes temporal summation -an increase in the number of units in the contraction results in spatial summation -at high stimulation levels, the Ca++ pumps in the SR can no longer remove Ca++ ions between action potentials and maximum tension generated, called tetanus

Critical area for most neurons? How this relates to EPSP and IPSP?

-for most neurons, the critical area for the "decision" to fire an action potential is the axon hillock. The plasma membrane of the axon hillock is not myelinated and has many voltage-gated ion channels. The plasma membrane of the axon itself also has many voltage-gated ion channels -however, the cell body (apart from the axon hillock) has essentially no voltage-gated ion channels and therefore EPSPs and IPSPs from synapses spread passively from the axon hillock -inputs from the synapses are conducted through the cell body. If the resulting combined potential depolarizes the axon hillock to threshold, the axon fires an action potential

Genetic therapy and plants? Examples?

-genetic therapy has not yet worked well in humans, but the creation of the transgenic plants has been successful and is big business (but controversial)

Hair cells in cochlea (ear)?

-hair cells are a special kind of mechanoreceptor found in the cochlea of the ear that respond to the vibration induced by sound

Hemophilia? Historical notes of hemophilia?

-hemophilia is a genetic disorder in which one or more of the clotting factors do not work. Even a minor wound can be serious -historical notes: Russian politics, blood transfusions in early days of the AIDS epidemic

What is hibernation? What is it regulated by? What is arousal from hibernation?

-hibernation is defined as a sustained and profound state of torpor, entry to and exit from which is governed by internal signals together with exclusively seasonal external cues -hibernation is regulated hypothermia that lasts days or weeks with drops to very low temperatures. The reduction in metabolic rate results in enormous energy savings -arousal from hibernation occurs when the hypothalamic set point temporarily returns to normal. During arousal, animals sometimes eat and/or urinate, then return to hypothermia

Thermoregulation, if lizard and mouse placed in same chamber? Metabolic rate differences to temperature?

-if a lizard (an ectotherm) and a mouse (an endotherm) are placed in a closed chamber in which the temperature is gradually raised, the body temperature of the lizard will equilibrate with that of the chamber, whereas the body temperature of the mouse will remain constant -the metabolic rates also respond differently. In the ectotherm, metabolism decreases as air temperature decreases -in the endotherm, metabolic rate increases as temperature decreases, which increases production of body heat

Effect of ethylene with Triple Response?

-if stems pushing up through soil encounter a stone, they release ethylene from their tips, which: 1) slows stem elongation 2) thickens the stem to make it stronger 3) makes the stem grow horizontally -these effects can be mimicked when treating plants with ethylene gas -ein mutants: fail to undergo the Triple Response in the presence of ethylene (ein = ethylene insensitive) -ctr mutants: undergo the Triple Response even in the absence of ethylene (ctr = constitutive triple response)

Thermoregulation: balancing heat loss and heat gain? Energy budget?

-if the body temperature of an animal is to remain constant, the heat entering the animal must equal the heat leaving the animal. This can be expressed as an energy budget: Heat in = Heat out Heat in = metabolism + solar radiation (Rabs) Heat out = radiation (Rout) + convection + conduction + evaporation -if heat is entering the body through convection and/or conduction, the sign of those factors change to negative -all of the components of heat loss (right side of the equation) depend on the surface temperature of the animal

Behavior- dance of honeybees if food source greater than 80m from hive?

-if the food source is more than 80m away from the hive, the "waggle dance" is used to convey information about distance and direction to the food source

Important parts of the eye? What creates a blindspot on the retina?

-important parts of eye: cornea, aqueous humor, iris, pupil, lens, vitreous humor, retina -there are no photoreceptors where blood vessels and the optic nerve (axons going to the brain) pass through the back of the eye. This creates a blind spot on the retina

Leaks in a closed circulatory system?

-in a closed circulatory system, leaks from damage to the blood vessels can be very serious. Leaks can be to the outside of an organism (cuts) or to the inside (hemorrhage, bruises)

Are the eye of squid and octopi a more logical design? In case of cephalopods?

-in cephalopods: photoreceptors are the first thing the light hits- thus less light scattering; no blind spot

Ionotropic sensory detection? Metabotropic sensory detection?

-in ionotropic sensory detection, the receptor protein itself is part of the ion channel and, by changing its conformation, opens or closes the channel pore -in metabotropic sensory detection, the receptor protein is linked to a G protein that activates a cascade of events that eventually open or close ion channels

Regulation of thermoregulation in mammals? Sensors?

-in mammals, thermoregulation is controlled in the hypothalamus -warm sensors signal the hypothalamic thermostat when the temperature of the blood increases, activating cooling mechanisms -likewise, cold sensors activate heating mechanisms

The cardiac cycle? Ventricle contraction and relaxation? What are the sounds of the cardiac cycle from?

-in the cardiac cycle, ventricle contraction is systole and ventricle relaxation is diastole. At the end of the diastole, the atria contract -the sounds of the cardiac cycle (lub-dub) are caused by the closure of heart valves. Defective valves produce heart murmurs (whooshing sounds followed by the lub) -the cardiac cycle can also be felt in artery pulsation, the surge of blood during systol

Rod cells in the dark?

-in the dark, a rod cell has a depolarized resting potential because Na+ channels in the plasma membrane of the outer segment are (partially) open -when light is absorbed by rhodopsin, it becomes photoexcited and activates a G protein called transducin -activated transducin activates a cGMP phosphodiesterase, which converts cGMP to GMP -in the dark, cGMP keeps Na+ channels open; in light, cGMP levels fall and channels close

Rod cells in dark and light (regarding polarization)?

-in the dark, a rod cell has a depolarized resting potential because Na+ ions can continually enter the outer segment; -in the light, cGMP phosphodiesterase converts cGMP to GMP and Na+ channels close. This causes the rod cell to hyperpolarize

What is reality? (input, brain, and brain chemistry)

-input: sensory/perceptions- we don't know everything that is out there -brain: mental health, good and bad feelings, ecstasy, despair, spiritual experiences -brain chemistry (and especially NTs and synapses) have major influences on our perception of reality

How does insect vision look?

-inspect vision probably looks more like mottled impressionist painting, where spots of paint are integrated by our brain into coherent images, especially pointalism

Action potentials- how fast? What is the speed of conduction determined by?

-invertebrates (un-insulated axons) -"giant axons" of squids and earthworms: up to 30 meters per second-used for rapid escape responses -small diameter axons conduct action potentials much more slowly (~5m/sec) -The speed of conduction is determined by: 1) speed of ion movement in the axoplasm 2) Leakage of ions across the plasma membrane 3) Kinetics of channel openings and closings

What is salicylic acid? Where does it come from?

-is a defense molecule produced by willow trees and is very similar to the active ingredient of aspirin -Hippocrates (5th ct) wrote about a bitter powder extracted from willow bark that could ease aches and pains and reduce fevers. -Nowadays salicylic acid is used as an anti-acne treatment -in plants, it functions in both the "systemic acquired resistance" to pathogens such as viruses, and it also functions as a hormone to signal unexposed areas of a plant that an infection is underway

What is ethylene? What does it do? Transgenic application?

-is a gas that acts as a plant hormone -promotes leaf abscission and fruit ripening -also causes an increase in its own production: as fruit ripens, more and more ethylene is produced -plant strains are being developed in which ethylene production is inactivated. Therefore, the fruits can't ripen by themselves. The fruits will be picked when large but green, transported to the site of sale, then exposed to endogenous ethylene to control ripening

What is the hematocrit?

-is a measure of the cellular portions as a percentage of the total blood volume

What is a "critical period" in regards to behavior?

-is a time, determined by developmental or hormonal state, during which exposure to certain stimuli produce virtually irreversible effects on behavior

Immune system: diversity?

-it is estimated that the human immune system can distinguish and respond to 10 million different antigenic determinants (epitopes)

Gravitropism? and involving auxin? Shoots and roots?

-lateral redistribution of auxin is also involved in gravitropism -if a shoot is tipped over, heavy statolith organelles sink to the bottom of cells and use Ca++ signaling to mediate transport of auxin to the lower side of the shoot, causing more rapid growth there. The seedling bends upward. -roots respond to auxin in the opposite manner

Learning and memory: synapses? How it relates to classical conditioning too?

-learning involves changes at synapses -repeated firing facilitates a synapse so that subsequent action potentials arriving at the same synapse release more NT vesicles than did the first action potential. This increases the probability that the later EPSPs will be more likely to elicit an action potential in the post synaptic cell (ditto for inhibition via IPSPs) -"classical conditioning" (Pavlov's dogs) involves associations between parallel synaptic pathways so that when one pathway is triggered, the other is also. Moreover, progression of Alzheimer's Disease correlates with the loss of synapses -High level activity at the synapse from presynaptic neuron N1 leads to recruitment of new synapses; lack of activity from N2 leads to loss of synapse from that presynaptic neuron. Much of this synaptic remodeling and consolidation of memories occurs at night when we sleep

The world outside of human perception (animal examples)?

-light: UV (bees), IR (snakes) -electric fields (fish) -echolocation (bats, dolphins) -infrasound (elephants) -magnetic fields (birds, butterflies?) -radio waves (including cell phone signals) -microwaves

Thermoregulation, most cell function in what range?

-living cells tolerate only a narrow range of temperature -most cell function is limited to the range between 0'C and 45'C -however, some organisms are able to tolerate extremes

Non-specific defenses: macrophages?

-macrophages live longer and consume larger numbers of pathogens than do neutrophils. Some roam and others are stationary in lymph nodes and lymphoid tissue

Learning and memory: synapses, details about learning associated changes? Glutamatergic synapses?

-many learning associated changes at the synapse involve changes in the recruitment of receptors to postsynaptic membranes and/or phosphorylation of (a) proteins that modulate the amount of NT release or (b) receptors, which changes their sensitivity. An example of these changes is long-term potentiation (LTP) at glutamatergic synapses, which strengthen synaptic transmission -continued usage of glutamatergic synapse can recruit new receptors called AMPA receptors. Thereafter, glutamate release activates AMPA receptors (1) that trigger depolarization (2). The depolarization unblocks NMDA receptors (3). Together, the AMPA and NMDA receptors all Na+ and Ca++ influx that triggers bursts of action potentials (4). Phosphorylation of AMPA and NMDA receptors is also involved in LTP

What is the point of taking a blood pressure?

-measured by a stethoscope and a sphygmomanometer, which compares the systolic with the diastolic pressure. A normal young adult may show a systolic pressure of 120 mm Hg and diastolic of 80 mm Hg

Sensory receptors: touch (skin)? Surface? Deeper?

-mechanoreceptors are sensitive to mechanical forces. They are involved in many sensory systems, including skin sensations and sensing blood pressure. Physical distortion of a mechanoreceptor's plasma membrane causes ion channels to open -Surface: Merkel's disks adapt slowly and provide continuous information; Meissner's corpuscles adapt rapidly and are very sensitive -Deeper: Ruffini corpuscles adapt slowly and sense low frequency vibrations; Pacinian corpuscles adapt quickly and sense high frequency vibrations

What do auxins do? What is the most important one? What is phototropism?

-mediate many responses of plant shoots -most important is indoleacetic acid (IAA) -Phototropism is the tendency for plants to grow toward light sources. When light strikes a coleoptile from one side, the auxin moves to the shaded side, growth and cell elongation on that side is increased, and the seedling bends toward the light

Sensitivity of a physiological process to temperature? A quotient?

-most biochemical and physiological processes are temperature-sensitive, going faster at higher temperatures (up until proteins denature). The sensitivity of a physiological process to temperature is described as a quotient, Q10 -Q10 is defined as the rate of a reaction at a particular temperature (R(T)) divided by the rate of that reaction at a temperature 10'C lower (R(T-10) Q10 = (R(T))/(R(T-10)) -most biological Q10 values are ~2-3. Since not all of the component reactions in an organism have the same Q10, temperature change can disrupt the balance of physiological functioning. To maintain homeostasis, organisms must either compensate for or prevent temperature change

Characteristics of erythrocytes? How does it relate to bone marrow? Hemoglobin? What happens when hemoglobin level reaches 30% of the cell volume? Sickle cell anemia?

-most of the cells in blood are erythrocytes (RBCs). RBCs are biconcave, flexible discs packed with hemoglobin. -Hemoglobin carries O2, and the flexible shape of RBCs lets them squeeze through narrow capillaries -bone marrow makes about 2 million RBCs per second. Immature RBCs divide many times in the marrow and produce hemoglobin (Hb) -when the hemoglobin level reaches 30% of the cell volume, cell organelles including the nucleus break down, and the cell enters the circulation. Each RBC lives about 120 days and then is removed and broken down in the spleen -Bc RBCs are packed with Hb, mutations in Hb that alter its structure can have major effects on RBC shape, as in sickle-cell anemia

Motor cortex? Somatosensory cortex? What parts of body have large representation in the cortex?

-motor cortex: axons project to muscles in specific parts of the body; areas with fine motor control (eg face and hands) have the greatest representation -somatosensory cortex: receives touch and pressure information. The whole body surface can be mapped onto the somatosensory cortex -areas of the body that are capable of making fine discrimination in touch (eg lips, fingers in humans) have large representation in cortex

Learning and memory: synapses, motor skills?

-motor skills (walking, riding a bike, etc) are usually learned by repetition. An ensemble of synaptic connections is being reinforced and facilitated during the learning of these skills -once learned, a skill memory is difficult to unlearn. E.g., a person who has a tougher time learning the correct form than a beginner who is just learning a game. Habits are hard to break

Sarcomeres of skeletal muscle? Actin and myosin?

-myofibrils consist of repeating units called sarcomeres -each sarcomere is bound by Z lines, which anchor the thin actin filaments -at the center is the A band, housing all the myosin filaments -the M band contains proteins that support the myosin filaments -the H zone and I band are areas where actin and myosin do not overlap in relaxed muscle and therefore appear less dense -the bundles of myosin filaments are held in register by the protein titin -titin runs the full length of the sarcomere from Z line to Z line, and each titin molecule runs through the myosin bundle -actin = thin filaments -myosin = thick filaments

How to measure endogenous rhythms in humans?

-need isolation from sun, clocks, television, radio, noise in the environment, etc -isolation chambers, caves, hospital facilities, special rooms (eg human isolation facility) -when technicians are involved: randomized technician shifts, shave before work, etc -subjects are allowed to self select the timing of their sleeping and waking

Left/right lateralization of the cortex: split brain? Ball experiment?

-neurons on the the left and right sides of the cortex communicate via a major neural highway of axons called the corpus callosum -one treatment for severe cases of epilepsy in the past has involved the surgical cutting of the corpus callosum, resulting in humans whose brain is "split" such that the left and right sides of the cortex no longer communicate directly. This previous treatment led to experimental studies of so-called "split brain" humans -the neural components that are involved in speech are located in the left hemisphere of the brain

Where do neurons communicate with each other? What are synapses related to (disorder wise too)?

-neurons, and muscle cells, communicate at synapses -Synapses: learning and memory; progression of Alzheimer's disease correlates with the loss of synapses

Language areas of the cortex?

-normal language ability depends on the flow of information among various areas of the left cerebral cortex (in 95% of right handed people) -by imaging brain function, it is possible to see the metabolic activity in different brain areas when the brain is using language -for example, in repeating a spoken word, brain activity travels from the auditory cortex to Wernicke's area and then to Broca's area and the motor cortex -in repeating a written word, the flow of brain activity is from visual cortex to Wernicke's area (then to Broca's area to motor cortex) -several brain areas have been identified from persons who suffer brain damage and aphasia

Immune system: immunological memory?

-once exposed to a pathogen, the immune system remembers it and mounts future responses much more rapidly

Humans have three kinds of cone cells?

-one type absorbs violet and blue wavelengths, one absorbs green, and one absorbs yellow and red (all use retinal, but the interactions between retinal and the specific opsin determine the wavelength of absorption) -we cannot see ultraviolet light (<350nm) or infrared light (>750nm)

What about orientation of microfibrils?

-orientation of the microfibrils determines the orientation of cell expansion -for the cell to expand, the wall must loosen and stretch, and new microfibrils be deposited -auxin works by causing the release of proteins (H+) and proteins called expansins from the cytoplasm into the cell wall space. Expansins are activated by protons and modify H-bonding between polysaccharides in the plant wall

Sensory systems, broad overview?

-our senses provide information about the external world and our internal bodily sensations -sensory cells transduce physical or chemical stimuli into transmittable signals. Most sensory cells have membrane receptor proteins that detect a stimulus and alter a the flow of ions across the plasma membrane -the proteins that transduce physical/chemical stimuli into neural signals are the interface of our consciousness with the physical world

Studies of Wilder Penfield? What information did that result in?

-over 1935-1950: long-term memories last for years; electrical stimulation of specific locations on the temporal lobe elicited highly specific memories -immediate memory lasts only a few seconds and is almost perfectly photographic. Short term memory contains less information than immediate memory but lasts longer (10-15)

Potential different types of skeletal muscle?

-oxidative muscle cells (eg Type 1 red muscle) have many mitochondria and a lot of myoglobin to provide steady, prolonged ATP production. Long-term aerobic work such as running and swimming depend on this type of fiber -Glycolytic fibers (eg Type 2b white muscle) have fewer mitochondria and very little myoglobin. The myosin of fast-twitch fibers has a high ATPase activity, but cannot replenish ATP fast enough to sustain long-term contraction. Glycolytic fibers are ideal for situations that require sudden, maximum strength, such as weight lifting or sprinting

What are the advantages of separate circuits?

-oxygenated and deoxygenated blood can't mix -gas exchange is maximized because the lungs receive only blood with low O2 and high CO2 content -the separate circuits can operate at different pressures

What does the nervous system do?

-perceive -react -communicate -think -learn -remember -enable "consciousness"

Non-specific defenses: phagocytes, neutrophils, and macrophages? Mast cells?

-phagocytes engulf and digest foreign materials, especially pathogens or infected cells. There are several types, especially neutrophils, mast cells, monocytes, macrophages -neutrophils attack pathogens in infected tissue -monocytes mature into macrophages -mast cells release histamine when damaged and are important in the inflammation response and allergies

Organization of the retina?

-photoreceptors (rods and cones) synapse onto bipolar cells -bipolar cells (input from PRs, output to ganglion cells) -ganglion cells (axons project through the optic nerve to the brain)

Phototropin? Example of model plant Arabidopsis?

-plants use a variety of photoreceptor molecules for signal transduction signaling, including the family of phytochromes and the family of cryptochromes -the photoreceptor that initiates phototropism is a yellow pigmented protein: phototropin -upon absorbing blue light, phototropin initiates Ca++ signal transduction pathway leading to auxin redistribution, H+ and expansin secretion, and differential growth that leads to phototropic curvature -in the model plant Arabidopsis, mutations in phototropin yield plants that cannot bend toward light

Difference in cell structure of plants and animals?

-plants: cell walls, large vacuoles, chloroplasts (contain cpDNA), plasmodesmata (syncytium), polyploidy, self-fertilization possible (but not preferred)

What does plasma contain? What nutrients? What circulating proteins?

-plasma contains gases, ions, nutrients, proteins, hormones, and other stuff. Na+ and Cl- gives blood a salty taste -nutrients include glucose, amino acids, lipids, lactic acids, and cholesterol -circulating proteins include albumin, antibodies, hormones, fibrinogen, prothrombin, and carrier molecules

Left/right lateralization of the cortex generalizations? For motor and sensory functions?

-popular psychology often generalizes about different sides of the brain having characteristic functions, such as logical for the left side and creative for the right. However, although a lateral dominance is measurable, both hemispheres contribute to both kinds of processes -for motor and sensory function, the left side of the brain controls the right side of the body and the right side of the brain controls the left side of the body (body includes the motor and sensory functions of the face), while visual effects project as shown in the diagram

What is "push-through"? What does contraction of skeletal muscles do in regards to blood?

-pressure in the veins is very low, and blood movement back to the heart relies on the "push-through" from the arteries, gravity, vessel squeezing by skeletal muscles, breathing, and limited smooth muscle contraction -contraction of skeletal muscles pushes blood toward the heart because one-way valves in veins prevent backflow

Limitation of a tracheal system?

-puts a limit on the size of the organism because passive diffusion of gases down the tubes can only go so far

The world beyond human perception? Rattlesnake example? Bees?

-rattlesnakes have nostrils that detect infrared irradiation (>750nm) that detects heat of rodents -bees for ultraviolet irradiation (<350nm) for flowers

Relevant questions about observed behavior? What are are ethologists? Comparative psychology?

-relevant questions: nature versus nurture? Instinct versus learning? Genetics vs environment? -ethologists study the behavior of animals in their natural environments. They are particularly interested in stereotyped, species-specific patterns of behavior, but also in the extent that behaviors are due to inheritances vs. experience -the parallel field of comparative psychology focuses on learning by animals in lab environments

Where has our understanding of learning and memory come from?

-research on the marine slug Aplysia (the sea hare)

Schizophrenia? Related to what NTs?

-schizophrenics often suffer terrifying symptoms such as hearing internal voices not heard by others, or believing that other people are reading their minds, controlling their thoughts, or plotting to harm them -significant genetic component -related to the NTs dopamine and glutamate. Amphetamine ("speed") produce symptoms like those of schizophrenia. Some drugs that are effective against schizophrenia block a specific type of dopamine receptor. Glutamate receptors (esp. the NMDA receptor involved in LTP) is also implicated

Behavior- migration? Experiments with starlings?

-seasonal movement between breeding and nonbreeding grounds is called migration -many homing and migrating species are able to take direct routes to their destinations, even through environments they have never experienced before -experiments with starlings showed that naive juvenile birds were using distance- and direction-navigation -experienced adult birds were not disrupted by geographic displacement

Plants: what are secondary metabolites? Where are they stored? How do humans make commercial use out of secondary metabolites?

-secondary metabolites are special chemicals that are not used for cellular metabolism; they may attract pollinators and/or repel/poison predators -they are frequently stored in the large vacuoles of the cells (because of turgor pressure/wilting) -make commercial use as fungicides, insecticides, rodenticides, and pharmceuticals

Sensory systems and reality?

-sensory systems represent the external world to the CNS -our perceptions are neural constructs, not direct readouts of physical stimuli -sensory systems can be tricked

What is different about the 4-chambered hearts of birds and mammals?

-separate from the pulmonary and systemic circuits

non-FDA approved uses of botox?

-severely cold hands, lockjaw, backpain, depression, drooling, teeth grinding

Later studies inspired by Darwin's coleoptile experiments?

-showed that the coleoptile tip produces a hormone that diffuses down the stem -if the tip is removed, growth is inhibited. If the tip is replaced, growth resumes, even if a layer of gelatin is placed in between -in the 1920s, Frits Went isolated the hormone by placing coleoptile tips on gelatin blocks. The hormone, later determined to be IAA, diffused into the gelatin, and the gelatin block then had the same effect as the coleoptile tip

Evolution of the eye in mollusks?

-shows a progression of complexity; even simple photoreceptors are apparently adaptive -mollusks include snails, shellfish, squids, octopi

Immune system, surface barriers?

-skin -mucus: a) respiratory tract (also nostril hairs) b) digestive tract c) saliva d) tears -lysozymes

Some consequences of having a clock for humans (shift-work, jet-lag, poor eating habits, working at non-optimal hours, etc)?

-sleep disorders -fatigue -impaired performance/alertness -affective disorders (depression, etc) -gastrointestinal and cardiovascular problems, cancer -metabolic disorders -accidents -medical costs

Smooth muscle cells and arteries? Relation to precapillary sphincters? What are these smooth muscles regulated by? What do these autoregulatory actions influence?

-smooth muscle cells in arteries and arterioles contract and relax, varying the vessels' diameter, which changes the resistance to flow and allows blood to be distributed to different tissues -also, there are precapillary sphincters made of smooth muscles at the entrance to capillary beds that regulate blood flow into capillaries -these smooth muscles are under hormonal and neural control, eg, endothelium for vasoconstriction and NO for vasodilation -the collective autoregulatory actions of all the capillary beds influence the pressure throughout the body. For example, if many capillary beds dilate all at once, blood pressure drops

Synapses: spatial and temporal summation?

-spatial and temporal summation adds up the simultaneous influences of synapses at different sites/times on the postsynaptic cell

Stem cells relation to platelets?

-stem cells in marrow also produce megakaryocytes, which break off cell fragments called platelets. Platelets contain enzymes and chemicals necessary for blood clotting

Functions of glia cells?

-structural support -nutrient support (eg glucose, lactate) -blood-brain barrier -neurotransmitter reuptake -ion homeostasis (eg potassium)

What poison acts on the nervous system that is concentrated in the liver and other organs of the pufferfish fugu?

-tetrodotoxin is a poison that is concentrated in the liver and other internal organs of the pufferfish fugu -it is a very potent inhibitor of the voltage gated Na+ channel -after ingesting just a small amount of tetrodotoxin, action potentials stop

Plants and "solar-power"?

-the "solar-power" comes from photosynthesis, which occurs in chloroplasts

How is the AV node stimulated? The effects?

-the atrioventricular node (AV) is stimulated by depolarization of the atria; after a 0.1 sec delay the AV generates action potentials that are conducted to the ventricles via specialized bundle of muscle fibers called the Bundle of His and thence to the left and right Bundle branches -the Bundle branches spread throughout the ventricular muscle mass as Purkinje Fibers -Purkinje fibers evenly distribute the action potential throughout the ventricular muscle -the delay in the spread of action potentials ensures that the ventricles contract after the atria do

How does changing the ion permeabilities change the Vm?

-the basis for almost all electrical signals in the nervous system is that Vm can change from its resting value when the membrane's permeability to particular ions change. -opening and closing of ion channels, which results in changes in ion permeability, are the basic mechanisms by which neurons respond to stimuli

Best approach to reduce heart attacks and strokes? Risk factors? What does "good cholesterol" mean vs bad?

-the best approach to reducing heart disease and strokes is prevention -risk factors include high fat diets, smoking, a sedentary lifestyle, diabetes, and obesity -"good cholesterol" is high-density lipoproteins (HDLs) that reduces the deposition of cholesterol in arterial plaques, whereas "bad cholesterol" is low-density lipoproteins (LDLs) that increase deposition in plaques

What is an open circulatory system? What type of species has it?

-the blood or circulating fluid is not kept separate from the tissue fluid -often a pump ("heart") helps to propel the fluid, and vessels direct it, but the fluid leaves the vessels to trickle through tissues -arthropods, mollusks, and other invertebrates use this type of circulatory system

-Thermoredulation: conserving heat. Endotherms adaptations for reducing heat loss in cold environments?

-the coldest environments are almost devoid of ectothermic reptiles or amphibians -Endotherms have many adaptations for reducing heat loss in cold environments: 1) reduction of surface-to-volume ratios of the body by short appendages and round body shapes 2) thermal insulation by thick layers of fur, feathers, and fat 3) decreasing blood flow to the skin by constricting blood vessels, especially in appendages

Evolutionary footnote for rhodopsin (Chlamydomonas)?

-the coupling of rhodopsin excitation and membrane potential changes is even true for single-celled plants (algae) such as Chlamydomonas and has led to the development of new "optogenetic" tools for stimulating neurons ("channelrhodopsins") -Moreover, the origin of the vertebrate eye was an early criticism of Darwin's theory, but the progression of photoreceptor complexity in mollusks now makes the evolution of the eye an excellent example in support of the theory of evolution

Basis of the resting Vm: equilibrium potentials? What can it be calculated by?

-the equilibrium potential (E) is the Vm (in millivolts) where the electrical gradient is "strong enough" to attract ions back across the membrane, thereby stopping the net flow of ions driven by the concentration gradient of that ion. -It can be calculated by the Nernst equation

Memory and the brain: plasticity? STM? LTM? Early evidence of memories having a location?

-the formation of memories is an example of neural plasticity -short term memory is assessed via the hippocampus -the hippocampus also plays a role in forming long term memory, which is stored in the cerebral cortex, including the temporal lobes of the cortex -early evidence that memories have "anatomical locations" in the brain came from studies of people with epilepsy, who reported vivid memories when some regions of the temporal lobe cortex were stimulated (studies of Wilder Penfield, 1935-1950)

The immune system: recognizing self vs non-self? The four groups of proteins that play key roles in defending against disease?

-the immune system is acquired/adaptive immunity -recognition of self vs non-self is mostly based on cell-surface proteins (usually glycoproteins; a molecular fingerprint) (MHC) -Four groups of proteins play key roles in defending against disease: 1) antibodies: secreted by B cells, bind specifically to certain substances (not the same as antibiotics) 2) T cell receptors: are cell surface receptors that bind non-self substances on the surface of other cells 3) Major histocompatibility complex (MHC) proteins are exposed on outside surface of mammalian cells. These proteins help to distinguish self from non-self 4) Cytokines: are soluble signal proteins released by T cells and macrophages. They bind and alter the behavior of their target cells (as well as signaling the brain to produce a fever)

Non-specific defenses: the inflammation response? Macrophages and neutrophils? What do they produce? Pus?

-the inflammation response is used in dealing with infection or tissue damage locally -the macrophages and neutrophils engulf invaders and debris and are responsible for most of the healing. They produce several cytokines, which may signal the brain to produce a fever. -Pus, composed of dead cells and leaked fluid, may accumulate

Anatomy of the human heart? Purposes of pumps and valves? Why is the left ventricle more muscular?

-the left and right sides of the human heart may be thought of as separate pumps -left pump -- systemic circuit -right pump -- pulmonary circuit -pulmonary valve and aortic valves prevent backflow into the ventricles -atrioventricular valves between the atria and ventricles prevent backflow into the atria when the ventricles contract -the left ventricle is more muscular because the resistance of the systemic circuit is much greater

How does the lens make adjustments and why? What is the most sensitive area (for resolution) of the retina? Difference with raptors?

-the lens makes fine adjustments in the focus of images on the photosensitive retina at the back of the eye. Mammals and birds alter the shape of the lens to focus -the most sensitive area (for resolution) of the retina is the fovea -Raptors such as falcons, eagles, and hawks have two fovea, and the density of the photoreceptors within these two fovea are 10X more dense than in the human fovea

What is near and far-sightedness due to? What are the technical terms for near and far-sightedness? How do lenses change with age?

-the most common types of near-sightedness and far-sightedness are due to changes in the shape of the eyeball that put the focal length outside of the range in which the lens is able to focus -lenses become less elastic with age and we lose the ability to focus on objects close at hand (presbyopia)

Skeletal muscle and strength and aerobic exercises?

-the proportion of slow to fast twitch fibers in your muscle is largely determined by inheritance, but exercise also influences muscle size, endurance, and activity: -strength exercises: like weight-lifting increase the number of new actin and myosin filaments, hence, bigger muscles -aerobic exercises: enhances the oxidative capacity of muscles by increasing the density of capillaries in the muscles as well as by increasing the myoglobin content and number of mitochondria in fast twitch fibers (this converts some fast-twitch glycolytic Type 2b to fast-twitch oxidative Type 2a fibers)

How is thermogenesis increased? How else can thermogenesis occur?

-thermogenesis is increased by muscle activity such as moving or shivering -thermogenesis can also occur by metabolism within "brown fat" (non-shivering thermogenesis). Brown fat is especially abundant in newborn human infants and in animals that hibernate -the tissue looks brown because of its abundant mitochondria and rich blood supply. Brown fat cells have the protein thermogenin that uncouples protein movement in the mitochondria from ATP production, so that heat is produced instead of ATP

What are daily biological clocks? What are their properties?

-they are circadian rhythms -Properties: a) they continue to oscillate in "constant conditions with a period of approximately 24 hours (therefore, there is an endogenous biological clock inside of us) b) these internal clocks run at about the same speed at different temperatures, even in cold blooded animals and plants c) normally, these internal clocks are synchronized to the daily light/dark cycle of exactly 24 hours

Heart attack and ischemic stroke process?

-they are often the end result of atherosclerosis (hardening of the arteries) -if smooth internal lining of arteries become damaged, deposits of lipids and cholesterols (called plaque) can form at damaged sites -the plaque becomes infiltrated with fibrous connective tissue and calcium deposits, which make the artery wall less elastic (hardening). -the plaque narrows the lumen of the artery -a blood clot (thrombus) made of platelets and pieces of plaque broken off from another site can lodge at the plaque, further blocking the artery -if the coronary arteries are affected, blood supply to the heart decreases -a thrombus here (coronary thrombosis) can block an artery, causing a heart attack (myocardial infarction, MI)

Human Freerun under isolation conditions?

-this human subject was isolated from any outside influences (including other humans) for 128 days and self-selected his/her timing of sleep and wakefulness

Why are large artery walls elastic? Anatomy of artery and vein?

-to withstand high pressures and to squeeze blood along by elastic rebound

What is torpor? What is it regulated by?

-torpor is best defined as entry of the whole animal into a state of hypothermia which is accompanied by behavioral inactivity and decreased activity and metabolism that enables animals to save energy. -It is regulated by a combination of external and internal signals. Torpor is more common in smaller animals, and is most often accompanied by a significant drop in body temperature

Examples of stimuli and receptors?

-touch and/or stretch via mechanoreceptors -pressure via mechanoreceptors -sound via specialized mechanoreceptors -light via photoreceptors -heat via thermoreceptors -odors via chemoreceptors -taste via chemoreceptors -pain via pain receptors (= nociceptors) -magnetic field via electromagnetic receptors (?)

Making transgenic plants?

-transgenes are inserted into plasmids that can be transferred to the plant by infection with the bacterium Agrobacterium -usually an antibiotic resistance (kanacyin or gentamycin) is linked to the transgene of interest to select for transformed -transformation is done on shoot or leaf tissue that forms a callus when grown on agar medium

How do varicose veins develop? What do the valves look like?

-varicose veins develop if veins become stretched, and the valves no longer do their job

Sensory system: vision (eyes) vertebrates?

-vertebrate eyes have rods and cones -a rod cell is a modified neuron that has an outer segment, an inner segment, and a synaptic terminal -the inner segment has a nucleus and many mitochondria -the outer segment has a stack of membrane-bound discs that are densely packed with rhodopsin. The discs function to capture photons -light causes the rod cell to hyperpolarize

What two types of species has highly evolved eyes?

-vertebrates and cephalopod mollusks (ex red octopus)

Vertebrates have what in regards to what? Valves prevent what when heart contracts? Circuits of blood in vertebrate evolution? What does the circuit look like in fish, amphibians, and reptiles?

-vertebrates have closed circulatory systems and hearts with 2 or more chambers. -valves prevent blood backflow when the heart contracts -a theme in vertebrate evolution is a progressive separation of the blood that goes to the lungs from the blood that goes to the rest of the body, culminating in two circuits: a pulmonary (lung) circuit and a systemic (body) circuit

Skeletal muscle? How does it move? What are connecting tissues?

-voluntary movements are controlled by skeletal muscle, ie they are under our conscious control -skeletal muscle is also called "striated muscle" because of its striped appearance (due to the regular arrangements of their actin and myosin filaments) -skeletal muscle cells are called muscle fibers. They are large and have many nuclei -skeletal muscle moves the body by contraction (muscle can't actively extend). Movement around joints is accomplished by antagonistic muscle pairs- one contracting, the other relaxing -Connecting tissue: a) ligaments hold bones together at a joint b) tendons attach muscles to bones

What is the thermoneutral zone? What does it have to do with metabolic rates? What happens when the environmental temperatures drop below the lower critical temperature (mammals, bird)?

-within a narrow range of temperatures, the thermoneutral zone, the metabolic rate of endotherms is low and independent of temperature. The thermoneutral zone is bounded by a lower critical and upper critical temperature -when environmental temperatures drop below the lower critical temperature, mammals thermoregulate by generating heat (thermogenesis) through shivering and nonshivering heat production. Birds only use the shivering mechanism. -in shivering, skeletal muscles use ATP to release only heat. Active body movement also generates heat

What does an open circulatory system work well for? What has it been separated from?

-work well for circulation of nutrients and waste, but usually are not rapid and efficient for O2 and Co2 exchange if the metabolic rate is high -insects have separated their circulatory system from their gas exchange system, which is a completely separate and intricate network of tubes (trachea) that bring gas directly to the tissues

Dependency of brain and neuron survival? Ischemic and hemorrhagic stroke?

-your brain is very dependent upon oxygen and glucose. Neurons cannot survive for long without proper gas and nutrient exchange -if part of the thrombus breaks away (an embolism), lodging in the brain and blocking blood flow, ischemic stroke may occur. A stroke may also occur by the rupture of a blood vessel in the brain (hemorrhagic stroke) -frequently the part of the brain that is affected will die, resulting in irreversible brain damage or death

Ligand-gated channels- the ACh receptor. 3 step process?

1) ACh opens an Na+ channel on the postsynaptic membrane 2) Vm across the postsynaptic membrane depolarizes 3) ACh in the cleft is degraded by acetylcholinesterase, stopping the signal

Types of synapses? And important neurotransmitters?

1) Electrical synapses mediated by gap junctions (can't be easily modulated, can't be inhibitory, can't be summated temporally) 2) Chemical synapses: chemical neurotransmitter (NT) released from presynaptic cell and diffuses across the synaptic cleft (20-40nm) to the postsynaptic cell. Important NTs: a) acetylcholine (ACh): synapses between motor neurons and muscle cells (aka neuromuscular junction), excitatory b) serotonin- generally inhibitory c) dopamine- generally excitatory d) glutamate- excitatory e) norepinephrine- excitatory or inhibitory f) glycine- inhibitory (open Cl- channels) g) GABA- inhibitory (open Cl- channels) h) neuropeptides (eg, Substance P) i) nitric oxide (NO)

How are the synaptic signals stopped?

1) NT is released from presynaptic termini as very brief bursts, so channels in the postsynaptic membranes are open for very brief intervals. When the channels close, the Vm rapidly returns to the resting Vm that is largely determined by the K+ electrochemical gradient 2) NT is rapidly removed from the synaptic cleft by one or more of the following mechanisms: a) NT is degraded in the synaptic cleft (eg, ACh is degraded by acetylcholinesterase) b) NT diffuses out of the synaptic cleft c) NT is taken up by transporters in the membranes of the presynaptic cell and repackaged/recycled OR taken up by adjacent glial cells --the action of many drugs and anesthetics is at synapses

Ventricular muscle cell action potentials?

1) first phase is initiated by voltage-gated Na+ channels 2) second phase: voltage gated Ca++ channels open, and they don't close quickly -as long as the Ca++ channels remain open, the ventricular muscle cells continue to contract (for about 300 msec)

What are the four characteristics of the immune system?

1) specificity 2) diversity 3) distinguishing self from non-self 4) immunological memory

Warning signs: the symptoms of strokes (distinct because they happen quickly)?

1) sudden numbness or weakness of the face, arm, or leg (especially on one side of the body) 2) sudden confusion, trouble speaking or understanding speech 3) sudden trouble seeing in one or both eyes 4) sudden trouble walking, dizziness, loss of balance or coordination 5) sudden severe headache with no known cause

The contraction cycle regarding Ca++, troponin, and tropomyosin?

1) when the muscle is at rest, two proteins, tropomyosin and troponin, block the myosin binding sites on the actin filament 2) if troponin binds Ca++, troponin and tropomyosin change shape, unmasking the myosin binding sites on actin -with the binding sites exposed, the actin-myosin bonds are made, and the filaments are pulled past each other, resulting in muscle fiber contraction -Troponin binds Ca++ and undergoes a conformational change (structure of troponin is very similar to that of calmodulin)

Defenders against disease, the immune system: The enemies? The non-specific defenses? Specific and adaptive response?

The enemies: -pathogenic bacteria (and their toxins) -pathogenic viruses -pathogenic fungi and protozoa -virus-infected cells -cancerous cells Non-specific defenses: -barriers -complement proteins -phagocytes et al -inflammatory response Specific and adaptive response: -the immune system

What is the symbol for membrane potential?

Vm

What does the trachea, gills, and lungs do and for what?

maximize surface area for gas exchange

Non-specific defenses, complement proteins? Types of defenses?

~30 antimicrobial complement proteins in vertebrates. Complement proteins provide three types of defenses: 1) they attache to microbes, helping phagocytes recognize and destroy them 2) they activate the inflammation response and attract phagocytes to the site of infection 3) they lyse invading cells